Re: [EVDL] Zero self-discharge (was: Bicycle battery)
Very short on important details like what chemistry cell did they use. If LiFePO4 they were doomed when they used 4.0V and 4.2V as their charge voltages. If some other chemistry then maybe not. They also don't show any reversible capacity loss data. Why? A very poorly done paper without enough information to know if the results are even worth anything. On Fri, Jun 19, 2015 at 5:58 PM, Cor van de Water via EV ev@lists.evdl.org wrote: David, Here is a paper describing the chemical and physical mechanisms inside a Li-Ion cell that cause self-discharge. Happy reading! http://www.che.sc.edu/faculty/popov/drbnp/WebSite/MSA-calendar.pdf Regards, Cor van de Water Chief Scientist Proxim Wireless office +1 408 383 7626 Skype: cor_van_de_water XoIP +31 87 784 1130 private: cvandewater.info www.proxim.com This email message (including any attachments) contains confidential and proprietary information of Proxim Wireless Corporation. If you received this message in error, please delete it and notify the sender. Any unauthorized use, disclosure, distribution, or copying of any part of this message is prohibited. -Original Message- From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of David Nelson via EV Sent: Friday, June 19, 2015 4:37 PM To: Bill Dube; Electric Vehicle Discussion List Subject: Re: [EVDL] Zero self-discharge (was: Bicycle battery) Bill, I have dug through many scientific papers on Li batteries and how they work and I haven't been able to find anything about a theoretical self-discharge mechanism. I have found some explicitly talking about the lack of a charge shuttle mechanism like in lead-acid batteries, however. One paper I read has a section devoted to figuring out a charge shuttle mechanism to add to a Li cell. It isn't a paper for the faint of heart, however. It is Nonaqueous Liquid Electrolytes for Lithium-Based Rechargeable Batteries by Kang Xu published in the Chemical Review, 2004, Vol. 104, No. 10, pp. 4303-4417 and published on the web 09/16/2004. While I'm sure I don't get it 100% of the time I try to make sure I say, LiFePO4 cells have no theoretical self discharge mechanism. This, according to all I have been able to find on the cells, is true. Also, the most ardent anti-BMS people I have found have in fact done a lot of searching of the scientific literature and came to the same conclusion. It was not just something they made up to support their anti-BMS position. If you have other literature showing what the self-discharge mechanism is please share it. On Fri, Jun 19, 2015 at 11:46 AM, Bill Dube via EV ev@lists.evdl.org wrote: This zero self-discharge myth seems to be a common thread with the anti-BMS crowd. I don't know where this misinformation comes from. All cells have self-discharge. It is just a matter of degree. Also, the self-discharge varies from cell to cell. That's why you need a BMS. These are well-documented facts for all those that care to investigate, either through the scientific literature or by simply systematically testing cells for themselves (as Lee Hart has done.) I strongly suspect the zero self-discharge myth comes from the same unscientific source that the anti-BMS myth has sprung from. Bill D. ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) -- David D. Nelson http://evalbum.com/1328 http://www.levforum.com ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) -- David D. Nelson http://evalbum.com/1328 http://www.levforum.com ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Zero self-discharge (was: Bicycle battery)
Sounds possible. My thoughts: Unfortunately, voltage is not a great way to evaluate cells, but that sounds good FWIW. Is your meter really reliable, and accurate to measure ±0.001 volts? under conditions of different temperature? Is the accuracy reall somewhat less good than ±0.001V? Recently calibrated? It is such a small amount that noise may be what you have read. The first time you read them was that 3.3V? Or 3.300V? Different meters used? To me 3.3V possibly means ±0.1V. One of the last things Dahn says in his lecture is essentially - want your cells to last a long time? Put them in the refrigerator very chance you get. Hard to do h an EV pack. Temperature is the enemy, and especially with LFP. Where were they stored for 16 months? It really becomes and important question when people are claiming a cell lasted or degraded of such and such a period of time. Also the SOC% which is hard to know without a full cycle and Ah measurement. That is really the topic change in amount of stored charge, not voltage changes. LFP particularly sees a lot of change in charge for little change in voltage. On Thu, Jun 25, 2015 at 6:24 PM, Paul Dove via EV ev@lists.evdl.org wrote: Here's my observation I received my cells and new the measured 3.3 volts. 16 months later when I put then in the vehicle they measured 3.298 and 3.297. Sent from my iPad On Jun 20, 2015, at 12:39 PM, Cor van de Water via EV ev@lists.evdl.org wrote: One last question and then I prefer not to extend this subject any longer since it appears beaten to death: Paul and Michael, Did you guys actually *measure* Li-Ion cells over extended period to verify if they show self-discharge or not? Because the interesting thing is that self-discharge is not only well defined (so it must be an issue) but it appears that everyone who measured Li-Ion cells over extended time periods (and not just a quick voltage check that they still had juice) is convinced that they do show self-discharge. To me, it seems to be the classical case of “in theory, there should be no difference between practice and theory. In practice, however…”. Regards, Cor van de Water Chief Scientist Proxim Wireless office +1 408 383 7626Skype: cor_van_de_water XoIP +31 87 784 1130private: cvandewater.info http://www.cvandewater.info www.proxim.com http://www.proxim.com/ This email message (including any attachments) contains confidential and proprietary information of Proxim Wireless Corporation. If you received this message in error, please delete it and notify the sender. Any unauthorized use, disclosure, distribution, or copying of any part of this message is prohibited. From: Michael Ross [mailto:michael.e.r...@gmail.com] Sent: Saturday, June 20, 2015 6:30 AM To: Cor van de Water; Electric Vehicle Discussion List Subject: Re: [EVDL] Zero self-discharge (was: Bicycle battery) I think this is going to come down to semantics and word definition. I bet Popov never looks into self discharge because it is a basic non existent occurrence in lithium ion batteries. Which is what Paul Dove and I have been saying. I saw in the paper linked by Cor that he used self discharge referring to capacity loss. Here is Dr. Popov's website: http://sc.edu/study/colleges_schools/engineering_and_computing/faculty-staff/popovbranko.php http://sc.edu/study/colleges_schools/engineering_and_computing/faculty-staff/popovbranko.php I went through the occurrences of lithium in the list and copied them for your edification below. I will pull out the ones that seem pertinent to self discharge and capacity loss in a separate posting. Mostly that is not what Popov is concerned with. *snip* -- next part -- An HTML attachment was scrubbed... URL: http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150620/977f30e9/attachment.htm -- next part -- A non-text attachment was scrubbed... Name: not available Type: image/png Size: 10048 bytes Desc: image001.png URL: http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150620/977f30e9/attachment.png ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA ( http://groups.yahoo.com/group/NEDRA) ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA ( http://groups.yahoo.com/group/NEDRA) -- To invent, you need a good imagination and a pile of junk. Thomas A. Edison http://www.brainyquote.com/quotes/quotes/t/thomasaed125362.html A public-opinion poll
Re: [EVDL] Zero self-discharge (was: Bicycle battery)
Here's my observation I received my cells and new the measured 3.3 volts. 16 months later when I put then in the vehicle they measured 3.298 and 3.297. Sent from my iPad On Jun 20, 2015, at 12:39 PM, Cor van de Water via EV ev@lists.evdl.org wrote: One last question and then I prefer not to extend this subject any longer since it appears beaten to death: Paul and Michael, Did you guys actually *measure* Li-Ion cells over extended period to verify if they show self-discharge or not? Because the interesting thing is that self-discharge is not only well defined (so it must be an issue) but it appears that everyone who measured Li-Ion cells over extended time periods (and not just a quick voltage check that they still had juice) is convinced that they do show self-discharge. To me, it seems to be the classical case of “in theory, there should be no difference between practice and theory. In practice, however…”. Regards, Cor van de Water Chief Scientist Proxim Wireless office +1 408 383 7626Skype: cor_van_de_water XoIP +31 87 784 1130private: cvandewater.info http://www.cvandewater.info www.proxim.com http://www.proxim.com/ This email message (including any attachments) contains confidential and proprietary information of Proxim Wireless Corporation. If you received this message in error, please delete it and notify the sender. Any unauthorized use, disclosure, distribution, or copying of any part of this message is prohibited. From: Michael Ross [mailto:michael.e.r...@gmail.com] Sent: Saturday, June 20, 2015 6:30 AM To: Cor van de Water; Electric Vehicle Discussion List Subject: Re: [EVDL] Zero self-discharge (was: Bicycle battery) I think this is going to come down to semantics and word definition. I bet Popov never looks into self discharge because it is a basic non existent occurrence in lithium ion batteries. Which is what Paul Dove and I have been saying. I saw in the paper linked by Cor that he used self discharge referring to capacity loss. Here is Dr. Popov's website: http://sc.edu/study/colleges_schools/engineering_and_computing/faculty-staff/popovbranko.php http://sc.edu/study/colleges_schools/engineering_and_computing/faculty-staff/popovbranko.php I went through the occurrences of lithium in the list and copied them for your edification below. I will pull out the ones that seem pertinent to self discharge and capacity loss in a separate posting. Mostly that is not what Popov is concerned with. *snip* -- next part -- An HTML attachment was scrubbed... URL: http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150620/977f30e9/attachment.htm -- next part -- A non-text attachment was scrubbed... Name: not available Type: image/png Size: 10048 bytes Desc: image001.png URL: http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150620/977f30e9/attachment.png ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Zero self-discharge
Folks, I hate to say it, but maybe it's time to tie a knot in this thread. Plenty of good information has come to light, but I don't see any of the major players budging an inch. If you really think it's worth arguing more about this, by all means carry on -- but please do it via private (off-list) email. Thanks, David Roden - Akron, Ohio, USA EVDL Administrator = = = = = = = = = = = = = = = = = = = = = = = = = = = = = EVDL Information: http://www.evdl.org/help/ = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Note: mail sent to evpost and etpost addresses will not reach me. To send a private message, please obtain my email address from the webpage http://www.evdl.org/help/ . = = = = = = = = = = = = = = = = = = = = = = = = = = = = = ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Zero self-discharge
I am not talking about LFP, I have no literature that is current about LFP. I have been talking more generally about LiMO2. All I have seen is contradictory, anecdotal info on LFP. Jack Richard doesn't think they have spontaneous loss of charge - and onl;y a small loss of SOC from sitting - 1% a year. I am sure with all chemistries there are poorly built and formed cells that are inferior. I am willing to bet, since the negative electrode is the same, and functions by intercalating li ions (which are agnostic once loosed from the positive electrode that there is no difference. WHether or not the negative electrode incorporates graphene or not, that only reflects on the number of intercalation sites. Does someone think that the negative electrode in LFP cells operates without intercalation? On Wed, Jun 24, 2015 at 12:52 AM, Roger Stockton via EV ev@lists.evdl.org wrote: Michael Ross wrote: It is like a bunch of people simply don't want to understand that things are not uniform across the field, that there is old tech that is being surpassed, and that some things are turning out very well. I would restate, I think it is possible that people don't recognise that some old and inferior cell designs do not represent what is possible, demonstrable and manufacturable. It seems you are ready to conveniently ignore the literature that you are happy to quote to others. There may or may not be something new about LiFePO4 chemistry that renders it immune to self-discharge, however, if there is, it is *not* the simple fact that lithium intercalation is involved, and this is something that you have been stating/purporting. Again, I refer you to your copy of Linden's Handbook of Batteries, which clearly states and quantifies self-discharge amounts for various lithium chemistries that *all* also rely upon lithium intercalation. If your claim is that something about LiFePO4 (in general, in theory, or some specific example?) that makes it immune to self-discharge, please make this clear in your posts, and accept that whatever this property is, it is not simply that LiFePO4 (like those other 'old and inferior [lithium] cell designs') relies upon lithium intercalation. Cheers, Roger. ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA ( http://groups.yahoo.com/group/NEDRA) -- To invent, you need a good imagination and a pile of junk. Thomas A. Edison http://www.brainyquote.com/quotes/quotes/t/thomasaed125362.html A public-opinion poll is no substitute for thought. *Warren Buffet* Michael E. Ross (919) 585-6737 Land (919) 576-0824 https://www.google.com/voice/b/0?pli=1#phones Google Phone (919) 631-1451 Cell michael.e.r...@gmail.com michael.e.r...@gmail.com -- next part -- An HTML attachment was scrubbed... URL: http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150624/6949ca9e/attachment.htm ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Zero self-discharge
Why would you stop it? This is certainly not like the H2 fuel discussions - not currently related to EVs. I liked those too from a philosophical POV This is a semi technical list - I don't get why a difference of opinions cannot involve a long running topic. I delete emails all the time that I do not care about, or have time for. I have no sympathy for the urge to get other people to stop talking about a subject that interests them. Not interested? Then don't read it. This topic is pertinent, it is being carried on with civility (not that that seems pertinent), it is interesting and ideas are being presented and the answers important. You know the conversation will not survive off list; you would just be killing it whether you admit it or not. I still want to hear how intercalation id not working - in LFP cells I guess, but I want to understand that. I am trying to follow up on the provided information from contrary sources (to my own); it takes time when no specific literature is presented. If there is a problem it is that there is rehashing because long conversations have newcomers that may not have been present or paying close attention at the start. On Wed, Jun 24, 2015 at 5:58 AM, Michael Ross michael.e.r...@gmail.com wrote: I am not talking about LFP, I have no literature that is current about LFP. I have been talking more generally about LiMO2. All I have seen is contradictory, anecdotal info on LFP. Jack Richard doesn't think they have spontaneous loss of charge - and onl;y a small loss of SOC from sitting - 1% a year. I am sure with all chemistries there are poorly built and formed cells that are inferior. I am willing to bet, since the negative electrode is the same, and functions by intercalating li ions (which are agnostic once loosed from the positive electrode that there is no difference. WHether or not the negative electrode incorporates graphene or not, that only reflects on the number of intercalation sites. Does someone think that the negative electrode in LFP cells operates without intercalation? On Wed, Jun 24, 2015 at 12:52 AM, Roger Stockton via EV ev@lists.evdl.org wrote: Michael Ross wrote: It is like a bunch of people simply don't want to understand that things are not uniform across the field, that there is old tech that is being surpassed, and that some things are turning out very well. I would restate, I think it is possible that people don't recognise that some old and inferior cell designs do not represent what is possible, demonstrable and manufacturable. It seems you are ready to conveniently ignore the literature that you are happy to quote to others. There may or may not be something new about LiFePO4 chemistry that renders it immune to self-discharge, however, if there is, it is *not* the simple fact that lithium intercalation is involved, and this is something that you have been stating/purporting. Again, I refer you to your copy of Linden's Handbook of Batteries, which clearly states and quantifies self-discharge amounts for various lithium chemistries that *all* also rely upon lithium intercalation. If your claim is that something about LiFePO4 (in general, in theory, or some specific example?) that makes it immune to self-discharge, please make this clear in your posts, and accept that whatever this property is, it is not simply that LiFePO4 (like those other 'old and inferior [lithium] cell designs') relies upon lithium intercalation. Cheers, Roger. ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA ( http://groups.yahoo.com/group/NEDRA) -- To invent, you need a good imagination and a pile of junk. Thomas A. Edison http://www.brainyquote.com/quotes/quotes/t/thomasaed125362.html A public-opinion poll is no substitute for thought. *Warren Buffet* Michael E. Ross (919) 585-6737 Land (919) 576-0824 https://www.google.com/voice/b/0?pli=1#phones Google Phone (919) 631-1451 Cell michael.e.r...@gmail.com michael.e.r...@gmail.com -- To invent, you need a good imagination and a pile of junk. Thomas A. Edison http://www.brainyquote.com/quotes/quotes/t/thomasaed125362.html A public-opinion poll is no substitute for thought. *Warren Buffet* Michael E. Ross (919) 585-6737 Land (919) 576-0824 https://www.google.com/voice/b/0?pli=1#phones Google Phone (919) 631-1451 Cell michael.e.r...@gmail.com michael.e.r...@gmail.com -- next part -- An HTML attachment was scrubbed... URL: http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150624/659b7c65/attachment.htm ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Zero self-discharge
Roger Stockton via EV wrote: I think that it is possible that people are confusing *theoretical* cell chemistry with that of *practical* cells. I think that is exactly the case. In theory, theory and practice are the same. In practice, they are not. -- Albert Einstein Of course there is an electric field inside a battery. Without an electric field, there would be no voltage, and you wouldn't have a battery. By definition, an electric field exists whenever there is a voltage difference between two points. The electric field provides the force that moves electrons and ions (polarized molecules) between plus and minus sides of the cell. These charges *will* find a way to leak. An analogy: The designers may *think* their wonderful new concrete dam doesn't leak a drop. But the tourist notices that the walls of the canyon below it are wet, and the farmer notices the change in ground water at his wells. The pressure is there, and the water *will* find ways around the dam, whether you like it or not. The important *practical* consideration is whether this leakage matters, or not. In a pacemaker, an ultra-low self-discharge rate is important (so they don't have to cut you open every few years to replace the battery)! In an EV that you can plug in any time you like, it's not very important. So, can we go back to discussing the practical aspects of EVs now? -- The greatest pleasure in life is to create something that wasn't there before. -- Roy Spence -- Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Zero self-discharge
Oh, yea, sorry I don't know why I was thinking magneticfield. At any rate the rest of what I said is accurate I believe.There is no electric field in a battery. A battery is a chemical reactor. The reaction is called red-ox reactions. In the battery is electrolyte which can conduct ions but not electrons. Electrons must move external to the battery. The potential in the battery is a chemical potential or the chemical energy. -- next part -- An HTML attachment was scrubbed... URL: http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150623/35499394/attachment.htm ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Zero self-discharge
So, let me try to paraphrase this. Are you saying that - the electrolyte can only conduct ions, - with an open circuit (nothing connected to the terminals), no electrons can move from one side to the other, - therefore, with an open circuit, there can be no loss of charge over time? In theory, that sounds solid. However, what if there is some internal leakage of electrons? What if the electrolyte is not a perfect insulator? Is it possible for some electrons to travel (and ions in the opposite direction) and some discharge to happen? Peri -- Original Message -- From: paul dove via EV ev@lists.evdl.org To: Electric Vehicle Discussion List ev@lists.evdl.org Sent: 23-Jun-15 1:21:20 PM Subject: Re: [EVDL] Zero self-discharge Oh, yea, sorry I don't know why I was thinking magneticfield. At any rate the rest of what I said is accurate I believe.There is no electric field in a battery. A battery is a chemical reactor. The reaction is called red-ox reactions. In the battery is electrolyte which can conduct ions but not electrons. Electrons must move external to the battery. The potential in the battery is a chemical potential or the chemical energy. -- next part -- An HTML attachment was scrubbed... URL: http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150623/35499394/attachment.htm ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Zero self-discharge
Just so you know you are getting over my head but this is the way I understand it. Inside a battery plain electrons can't travel around because it takes too much energy to put a plain electron in solution. Electrons can only travel inside the battery via charged chemicals, ions, which can dissolve off the electrodes. The chemical reaction is what pushes the electrons inside toward the negative end, because the electrodes at the two ends are made of different materials, which have different chemical stability. From: Peri Hartman pe...@kotatko.com To: paul dove dov...@bellsouth.net; Electric Vehicle Discussion List ev@lists.evdl.org Sent: Tuesday, June 23, 2015 3:34 PM Subject: Re[2]: [EVDL] Zero self-discharge So, let me try to paraphrase this. Are you saying that - the electrolyte can only conduct ions, - with an open circuit (nothing connected to the terminals), no electrons can move from one side to the other, - therefore, with an open circuit, there can be no loss of charge over time? In theory, that sounds solid. However, what if there is some internal leakage of electrons? What if the electrolyte is not a perfect insulator? Is it possible for some electrons to travel (and ions in the opposite direction) and some discharge to happen? Peri -- Original Message -- From: paul dove via EV ev@lists.evdl.org To: Electric Vehicle Discussion List ev@lists.evdl.org Sent: 23-Jun-15 1:21:20 PM Subject: Re: [EVDL] Zero self-discharge Oh, yea, sorry I don't know why I was thinking magneticfield. At any rate the rest of what I said is accurate I believe.There is no electric field in a battery. A battery is a chemical reactor. The reaction is called red-ox reactions. In the battery is electrolyte which can conduct ions but not electrons. Electrons must move external to the battery. The potential in the battery is a chemical potential or the chemical energy. -- next part -- An HTML attachment was scrubbed... URL: http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150623/35499394/attachment.htm ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) -- next part -- An HTML attachment was scrubbed... URL: http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150623/adbc1a29/attachment.htm ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Zero self-discharge
There is not an electric field inside a battery. The electrolyte cause the field to be in equilibrium otherwise it would immediately discharge. The field is present when the terminals are connected and that is why you get ion movement. Sent from my iPad On Jun 22, 2015, at 10:33 PM, Lee Hart via EV ev@lists.evdl.org wrote: Michael Ross via EV wrote: I am comparing to the lead acid chemistry where the charged state has a competing lower thermodynamic state, so a charge lead acid cell always runs down even in the absence of any short circuit or load. One of the neat things about Li ion cells that this condition does not exist. This is the self discharge that I am talking about. Well, Dahn says very clearly in his lecture there is no redox shuttle back to the positive electrode. Lack of any redox reactions doesn't mean there aren't any other sources of leakage and self-discharge. For example, capacitors have no redox shuttle, either... and yet they self-discharge. When you have a voltage difference, you also have an electric field. The strength of this field is usually measured in volts per meter. When the oppositely charged particles are very close together (micrometers), even a small voltage difference (like 3v) creates an enormous electric field strength (3 million volts per meter). Such a field strength can easily propel electrons from one side to the other; i.e. discharge the battery. -- The greatest pleasure in life is to create something that wasn't there before. -- Roy Spence -- Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Zero self-discharge
Michael Ross wrote: It is like a bunch of people simply don't want to understand that things are not uniform across the field, that there is old tech that is being surpassed, and that some things are turning out very well. I would restate, I think it is possible that people don't recognise that some old and inferior cell designs do not represent what is possible, demonstrable and manufacturable. It seems you are ready to conveniently ignore the literature that you are happy to quote to others. There may or may not be something new about LiFePO4 chemistry that renders it immune to self-discharge, however, if there is, it is *not* the simple fact that lithium intercalation is involved, and this is something that you have been stating/purporting. Again, I refer you to your copy of Linden's Handbook of Batteries, which clearly states and quantifies self-discharge amounts for various lithium chemistries that *all* also rely upon lithium intercalation. If your claim is that something about LiFePO4 (in general, in theory, or some specific example?) that makes it immune to self-discharge, please make this clear in your posts, and accept that whatever this property is, it is not simply that LiFePO4 (like those other 'old and inferior [lithium] cell designs') relies upon lithium intercalation. Cheers, Roger. ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Zero self-discharge
HI John, I would like to see where you got that idea from. I like reading original material. Other ion paths is not clear to me. My understanding is different. Batteries store chemical potential energy. There is no electric field as far as I know when you create a stable new chemical - in this case a lithiated negative electrode. The electrolyte isn't an insulator though you can measure the dielectric strength and argue about when that is or isn't an insulator. The electrolyte is a place for lithium ions to reside between the electrodes by way ol the lithium salt dissolved in it), but the separator (called such because that is its purpose to put some distance between the electrodes and reduces the chance of shorts) provides a volume for the electrolyte to fill. The ions in the electrolyte don't really flow. It is more like the desk toy of balls on strings and you pull an end and one away and let it go, it strikes then the far ball pops out. Even though the gap is very small and the ions can migrate, Jeff Dahn told me it takes a minute or so for an ion to actually traverse the very thin electrolyte from one electrode to the other. When a cell has lost its capacity it is because the ions in the electrolyte have been depleted by unhealthy chemical reactions at the positive electrode. There are fewer ionic balls in the electrolyte to knock ions from one electrode to the other. When the ions are intercalated in the negative electrode it is a new stable chemical that is created. It is even more reactive with the electrolyte and would tear it up if not for the SEI that forms. The new chemical formed in the positive electrode - the de-lithiated lithium metal oxide (or phosphate) - is also much more reactive than the discharged state chemical. No SEI forms here, and this is where the trouble starts for li ion cells when the temperature and SOC are to high because of the highly reactive nature of the chemical of the discharged positive electrode. When you let an electron pass from the negative electrode to the positive and ion de-intercalates and bangs an ion back into the Positive electrode. Cells, when designed well, don't offer a ready path for any electrons that aren't controlled by external circuitry. This how cells for medical implants can last for 10 or more years. If some poorly designed cells do offer a way to discharge spontaneously, that is a bad thing. It is incorrect to indict all lithium cells with this concept. You can do all you like to a lead acid cell and it will lose its charge internally. It doesn't have an intercalation function. The chemicals formed during charging naturally return to the discharged state over time and with temperature. On Tue, Jun 23, 2015 at 7:35 PM, John Lindsay via EV ev@lists.evdl.org wrote: There are other ion paths from impurities in the electrodes and electrolyte that allow charge to flow in the other direction thus closing the circuit. John Lindsay johnslind...@mac.com +61403577711 -- To invent, you need a good imagination and a pile of junk. Thomas A. Edison http://www.brainyquote.com/quotes/quotes/t/thomasaed125362.html A public-opinion poll is no substitute for thought. *Warren Buffet* Michael E. Ross (919) 585-6737 Land (919) 576-0824 https://www.google.com/voice/b/0?pli=1#phones Google Phone (919) 631-1451 Cell michael.e.r...@gmail.com michael.e.r...@gmail.com -- next part -- An HTML attachment was scrubbed... URL: http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150623/56e56c51/attachment.htm ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Zero self-discharge
There are other ion paths from impurities in the electrodes and electrolyte that allow charge to flow in the other direction thus closing the circuit. John Lindsay johnslind...@mac.com +61403577711 On 24 Jun 2015, at 6:24 am, paul dove via EV ev@lists.evdl.org wrote: Just so you know you are getting over my head but this is the way I understand it. Inside a battery plain electrons can't travel around because it takes too much energy to put a plain electron in solution. Electrons can only travel inside the battery via charged chemicals, ions, which can dissolve off the electrodes. The chemical reaction is what pushes the electrons inside toward the negative end, because the electrodes at the two ends are made of different materials, which have different chemical stability. From: Peri Hartman pe...@kotatko.com To: paul dove dov...@bellsouth.net; Electric Vehicle Discussion List ev@lists.evdl.org Sent: Tuesday, June 23, 2015 3:34 PM Subject: Re[2]: [EVDL] Zero self-discharge So, let me try to paraphrase this. Are you saying that - the electrolyte can only conduct ions, - with an open circuit (nothing connected to the terminals), no electrons can move from one side to the other, - therefore, with an open circuit, there can be no loss of charge over time? In theory, that sounds solid. However, what if there is some internal leakage of electrons? What if the electrolyte is not a perfect insulator? Is it possible for some electrons to travel (and ions in the opposite direction) and some discharge to happen? Peri -- Original Message -- From: paul dove via EV ev@lists.evdl.org To: Electric Vehicle Discussion List ev@lists.evdl.org Sent: 23-Jun-15 1:21:20 PM Subject: Re: [EVDL] Zero self-discharge Oh, yea, sorry I don't know why I was thinking magneticfield. At any rate the rest of what I said is accurate I believe.There is no electric field in a battery. A battery is a chemical reactor. The reaction is called red-ox reactions. In the battery is electrolyte which can conduct ions but not electrons. Electrons must move external to the battery. The potential in the battery is a chemical potential or the chemical energy. -- next part -- An HTML attachment was scrubbed... URL: http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150623/35499394/attachment.htm ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) -- next part -- An HTML attachment was scrubbed... URL: http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150623/adbc1a29/attachment.htm ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Zero self-discharge
Michael Ross via EV wrote: I am comparing to the lead acid chemistry where the charged state has a competing lower thermodynamic state, so a charge lead acid cell always runs down even in the absence of any short circuit or load. One of the neat things about Li ion cells that this condition does not exist. This is the self discharge that I am talking about. Well, Dahn says very clearly in his lecture there is no redox shuttle back to the positive electrode. Lack of any redox reactions doesn't mean there aren't any other sources of leakage and self-discharge. For example, capacitors have no redox shuttle, either... and yet they self-discharge. When you have a voltage difference, you also have an electric field. The strength of this field is usually measured in volts per meter. When the oppositely charged particles are very close together (micrometers), even a small voltage difference (like 3v) creates an enormous electric field strength (3 million volts per meter). Such a field strength can easily propel electrons from one side to the other; i.e. discharge the battery. -- The greatest pleasure in life is to create something that wasn't there before. -- Roy Spence -- Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Zero self-discharge (was: Bicycle battery)
I’m not sure what you mean by this. I am comparing to the lead acid chemistry where the charged state has a competing lower thermodynamic state, so a charge lead acid cell always runs down even in the absence of any short circuit or load. One of the neat things about Li ion cells that this condition does not exist. This is the self discharge that I am talking about. Well, Dahn says very clearly in his lecture there is no redox shuttle back to the positive electrode. It is in answer to a question in the last 10 minutes. He is talking mostly about Li Metal O2, like LiCOO2; not the LFP, usually. But I don't believe the activity at the negative, graphene electrode (as opposed to the LFP positive electrode) is any different in an LFP cell. The secret sauce of intercalation is the bistable nature it imparts to Li ion cells. The ions end up nestled with a circle of carbon atoms above and below that has no motivation for change (thermodynamically stable). In the Linden's Handbook of Batteries, Chapter 26, by Dr. Dahn is a nice discussion of how the negative electrode is manufactured, how and why it works. It is possible to make a negative electrode poorly. If the graphene is misaligned, poorly made, and so on, you can get ions into the electrode, but it would not be stable and the capacity would be low. If a low enough resistance path for electrons to the cathode is provided, lithium will move back to the cathode to combine with electrons there and form LiFePO4 I pretty much said the same thing. However, good cells don't have this. No cells I know of are using graphene for one of the electrodes. People are experimenting with it, but no cells in production. You are incorrect or maybe talking about LFP cells again. It is very hard to know everything that is going on, and lots of information becomes quickly dated. Check out the Linden's Handbook. On Mon, Jun 22, 2015 at 9:57 AM, tomw via EV ev@lists.evdl.org wrote: /“A lithium cell has no thermodynamic forcing function to move the ions back to the positive electrode. Stating this in the terms above - neither of the discharged or charge states are more stable than the other.”/ I’m not sure what you mean by this. Jay Whitacre (Materials Science, Carnegie Mellon): The phase change LiFePO4 to FePO4 occurs at 3.4V, redox reaction. During charging all lithium leaves the cathode, now have 3.4V driving Li back to the cathode when the charger is disconnected. - that's from the video I posted a link to after I posted the link to the video by Dahn. If a low enough resistance path for electrons to the cathode is provided, lithium will move back to the cathode to combine with electrons there and form LiFePO4, driven by the 3.4V chemical potential, with no external potential applied as during charging. Maybe by stable you mean this won't happen unless a low enough resistance path is provided, such as dendrites through the separator, conducting contamination on the cell packaging surface between electrodes, or an external wire connection. /A lot of the effort that goes into forming the negative electrode has to do with physically arranging little plates of graphene so that there is a large percentage of the volume in this fortuitous geometry./ No cells I know of are using graphene for one of the electrodes. People are experimenting with it, but no cells in production. Most use specially formulated graphite. Maybe that's what you meant since the carbon atoms bound in hexagons are arranged in sheets in graphite. Graphene is of course one of those single sheets, famously lifted with tape from a pencil mark when first studied, so I guess that is what you mean rather than an actual graphene electrode which would have quite different properties than graphite. -- View this message in context: http://electric-vehicle-discussion-list.413529.n4.nabble.com/Bicycle-battery-tp4676242p4676429.html Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com. ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA ( http://groups.yahoo.com/group/NEDRA) -- To invent, you need a good imagination and a pile of junk. Thomas A. Edison http://www.brainyquote.com/quotes/quotes/t/thomasaed125362.html A public-opinion poll is no substitute for thought. *Warren Buffet* Michael E. Ross (919) 585-6737 Land (919) 576-0824 https://www.google.com/voice/b/0?pli=1#phones Google Phone (919) 631-1451 Cell michael.e.r...@gmail.com michael.e.r...@gmail.com -- next part -- An HTML attachment was scrubbed... URL: http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150622/f77e09be/attachment.htm ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org
Re: [EVDL] Zero self-discharge (was: Bicycle battery)
Yes, but I'm not at home now. When I get back to town I'll share my data Sent from my iPhone On Jun 20, 2015, at 12:39 PM, Cor van de Water via EV ev@lists.evdl.org wrote: One last question and then I prefer not to extend this subject any longer since it appears beaten to death: Paul and Michael, Did you guys actually *measure* Li-Ion cells over extended period to verify if they show self-discharge or not? Because the interesting thing is that self-discharge is not only well defined (so it must be an issue) but it appears that everyone who measured Li-Ion cells over extended time periods (and not just a quick voltage check that they still had juice) is convinced that they do show self-discharge. To me, it seems to be the classical case of “in theory, there should be no difference between practice and theory. In practice, however…”. Regards, Cor van de Water Chief Scientist Proxim Wireless office +1 408 383 7626Skype: cor_van_de_water XoIP +31 87 784 1130private: cvandewater.info http://www.cvandewater.info www.proxim.com http://www.proxim.com/ This email message (including any attachments) contains confidential and proprietary information of Proxim Wireless Corporation. If you received this message in error, please delete it and notify the sender. Any unauthorized use, disclosure, distribution, or copying of any part of this message is prohibited. From: Michael Ross [mailto:michael.e.r...@gmail.com] Sent: Saturday, June 20, 2015 6:30 AM To: Cor van de Water; Electric Vehicle Discussion List Subject: Re: [EVDL] Zero self-discharge (was: Bicycle battery) I think this is going to come down to semantics and word definition. I bet Popov never looks into self discharge because it is a basic non existent occurrence in lithium ion batteries. Which is what Paul Dove and I have been saying. I saw in the paper linked by Cor that he used self discharge referring to capacity loss. Here is Dr. Popov's website: http://sc.edu/study/colleges_schools/engineering_and_computing/faculty-staff/popovbranko.php http://sc.edu/study/colleges_schools/engineering_and_computing/faculty-staff/popovbranko.php I went through the occurrences of lithium in the list and copied them for your edification below. I will pull out the ones that seem pertinent to self discharge and capacity loss in a separate posting. Mostly that is not what Popov is concerned with. *snip* -- next part -- An HTML attachment was scrubbed... URL: http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150620/977f30e9/attachment.htm -- next part -- A non-text attachment was scrubbed... Name: not available Type: image/png Size: 10048 bytes Desc: image001.png URL: http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150620/977f30e9/attachment.png ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Zero self-discharge (was: Bicycle battery)
people like me who monitor Li-Ion batteries over time, see and measure the self-discharge? I understand that you say theoretical the pure Li-Ion cell may not have a self discharge mechanism and thus the actual present self-discharge appears to be a spurious effect, possibly caused by contamination, so the amount of self-discharge is a quality indicator of the (lack of) contamination in the cell... However, saying that the ideal (theoretical) cell does not have any self-discharge is as valuable as saying that the ideal (theoretical) connection does not have any resistance. In practice however you better take that resistance into account when sizing your wiring and connections. Similar to taking self-discharge (and especially the difference in self-discharge between cells) into account when designing a battery pack. Cor van de Water Chief Scientist Proxim Wireless office +1 408 383 7626 Skype: cor_van_de_water XoIP +31 87 784 1130 private: cvandewater.info www.proxim.com This email message (including any attachments) contains confidential and proprietary information of Proxim Wireless Corporation. If you received this message in error, please delete it and notify the sender. Any unauthorized use, disclosure, distribution, or copying of any part of this message is prohibited. -Original Message- From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of David Nelson via EV Sent: Friday, June 19, 2015 4:37 PM To: Bill Dube; Electric Vehicle Discussion List Subject: Re: [EVDL] Zero self-discharge (was: Bicycle battery) Bill, I have dug through many scientific papers on Li batteries and how they work and I haven't been able to find anything about a theoretical self-discharge mechanism. I have found some explicitly talking about the lack of a charge shuttle mechanism like in lead-acid batteries, however. One paper I read has a section devoted to figuring out a charge shuttle mechanism to add to a Li cell. It isn't a paper for the faint of heart, however. It is Nonaqueous Liquid Electrolytes for Lithium-Based Rechargeable Batteries by Kang Xu published in the Chemical Review, 2004, Vol. 104, No. 10, pp. 4303-4417 and published on the web 09/16/2004. While I'm sure I don't get it 100% of the time I try to make sure I say, LiFePO4 cells have no theoretical self discharge mechanism. This, according to all I have been able to find on the cells, is true. Also, the most ardent anti-BMS people I have found have in fact done a lot of searching of the scientific literature and came to the same conclusion. It was not just something they made up to support their anti-BMS position. If you have other literature showing what the self-discharge mechanism is please share it. On Fri, Jun 19, 2015 at 11:46 AM, Bill Dube via EV ev@lists.evdl.org wrote: This zero self-discharge myth seems to be a common thread with the anti-BMS crowd. I don't know where this misinformation comes from. All cells have self-discharge. It is just a matter of degree. Also, the self-discharge varies from cell to cell. That's why you need a BMS. These are well-documented facts for all those that care to investigate, either through the scientific literature or by simply systematically testing cells for themselves (as Lee Hart has done.) I strongly suspect the zero self-discharge myth comes from the same unscientific source that the anti-BMS myth has sprung from. Bill D. ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) -- David D. Nelson http://evalbum.com/1328 http://www.levforum.com ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA ( http://groups.yahoo.com/group/NEDRA) ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA ( http://groups.yahoo.com/group/NEDRA) -- David D. Nelson http://evalbum.com/1328 http://www.levforum.com ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA ( http://groups.yahoo.com/group/NEDRA) -- To invent, you need a good imagination and a pile of junk. Thomas A. Edison http://www.brainyquote.com/quotes/quotes/t/thomasaed125362.html A public-opinion poll is no substitute for thought. *Warren Buffet* Michael E. Ross (919) 585-6737 Land (919) 576-0824 https
Re: [EVDL] Zero self-discharge (was: Bicycle battery)
Cor, Remember that there is a demand from people for some self discharge number. What easier way than just to make up a number? Maybe that is what they did and maybe that isn't. Lets not confuse capacity loss with self discharge. Also, a voltage measurement on a cell left to sit with no load doesn't prove self discharge either. Your analogy of an ideal circuit can't be used to size wiring doesn't apply because the theory does include resistance. I know what you are trying to say, however. It is just that so many people believe that self discharge exists and keep speaking it that many, including those who should know better, ignore things to justify their position. IIRC, you were one who told me that my battery pack would be way out of balance in a short period of time if I took my BMS boards off. Well, 4 years later and it hasn't happened. I say this, not to imply you don't know anything, but to show that we always need to be open to the fact that we might have missed something. Watch https://youtu.be/9qi03QawZEk. From the description: 'Published on Sep 6, 2013 On July 30th, 2013, Professor Jeff Dahn of Dalhousie University delivered a lecture entitled Why do Li-ion batteries die and can they be immortal?.' If you don't want to watch all 1:13:30 of it, which everyone on this list really should, skip to 1:09 where he directly answers the question about a charge shuttle reaction. He clearly said that no Li battery has one built in. Watch to the whole lecture where other things about Li cells are addressed. On Fri, Jun 19, 2015 at 5:11 PM, Cor van de Water via EV ev@lists.evdl.org wrote: David, Why do all manufacturers of Li-Ion batteries specify the amount of self-discharge and why do people like me who monitor Li-Ion batteries over time, see and measure the self-discharge? I understand that you say theoretical the pure Li-Ion cell may not have a self discharge mechanism and thus the actual present self-discharge appears to be a spurious effect, possibly caused by contamination, so the amount of self-discharge is a quality indicator of the (lack of) contamination in the cell... However, saying that the ideal (theoretical) cell does not have any self-discharge is as valuable as saying that the ideal (theoretical) connection does not have any resistance. In practice however you better take that resistance into account when sizing your wiring and connections. Similar to taking self-discharge (and especially the difference in self-discharge between cells) into account when designing a battery pack. Cor van de Water Chief Scientist Proxim Wireless office +1 408 383 7626 Skype: cor_van_de_water XoIP +31 87 784 1130 private: cvandewater.info www.proxim.com This email message (including any attachments) contains confidential and proprietary information of Proxim Wireless Corporation. If you received this message in error, please delete it and notify the sender. Any unauthorized use, disclosure, distribution, or copying of any part of this message is prohibited. -Original Message- From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of David Nelson via EV Sent: Friday, June 19, 2015 4:37 PM To: Bill Dube; Electric Vehicle Discussion List Subject: Re: [EVDL] Zero self-discharge (was: Bicycle battery) Bill, I have dug through many scientific papers on Li batteries and how they work and I haven't been able to find anything about a theoretical self-discharge mechanism. I have found some explicitly talking about the lack of a charge shuttle mechanism like in lead-acid batteries, however. One paper I read has a section devoted to figuring out a charge shuttle mechanism to add to a Li cell. It isn't a paper for the faint of heart, however. It is Nonaqueous Liquid Electrolytes for Lithium-Based Rechargeable Batteries by Kang Xu published in the Chemical Review, 2004, Vol. 104, No. 10, pp. 4303-4417 and published on the web 09/16/2004. While I'm sure I don't get it 100% of the time I try to make sure I say, LiFePO4 cells have no theoretical self discharge mechanism. This, according to all I have been able to find on the cells, is true. Also, the most ardent anti-BMS people I have found have in fact done a lot of searching of the scientific literature and came to the same conclusion. It was not just something they made up to support their anti-BMS position. If you have other literature showing what the self-discharge mechanism is please share it. On Fri, Jun 19, 2015 at 11:46 AM, Bill Dube via EV ev@lists.evdl.org wrote: This zero self-discharge myth seems to be a common thread with the anti-BMS crowd. I don't know where this misinformation comes from. All cells have self-discharge. It is just a matter of degree. Also, the self-discharge varies from cell to cell. That's why you need a BMS. These are well-documented facts for all those that care to investigate, either
Re: [EVDL] Zero self-discharge (was: Bicycle battery)
Hi Michael, From the link you could have gone to this prof’s website, but here is an easy to use list of all his freely available publications, he has done a lot of work on applications of rechargeable batteries: http://www.che.sc.edu/faculty/popov/drbnp/website/pubbooks.html Hope this helps, Cor van de Water Chief Scientist Proxim Wireless office +1 408 383 7626Skype: cor_van_de_water XoIP +31 87 784 1130private: cvandewater.info http://www.cvandewater.info www.proxim.com http://www.proxim.com/ This email message (including any attachments) contains confidential and proprietary information of Proxim Wireless Corporation. If you received this message in error, please delete it and notify the sender. Any unauthorized use, disclosure, distribution, or copying of any part of this message is prohibited. From: Michael Ross [mailto:michael.e.r...@gmail.com] Sent: Friday, June 19, 2015 8:06 PM To: Cor van de Water; Electric Vehicle Discussion List Subject: Re: [EVDL] Zero self-discharge (was: Bicycle battery) Cor, There is no author, no date, no publisher, no prior art, and no references. Was it in a journal, is the peer review? Has it been repeated? Is there a more complete copy or a place where it can be purchased? On Fri, Jun 19, 2015 at 8:58 PM, Cor van de Water via EV ev@lists.evdl.org wrote: David, Here is a paper describing the chemical and physical mechanisms inside a Li-Ion cell that cause self-discharge. Happy reading! http://www.che.sc.edu/faculty/popov/drbnp/WebSite/MSA-calendar.pdf Regards, Cor van de Water Chief Scientist Proxim Wireless office +1 408 383 7626 tel:%2B1%20408%20383%207626 Skype: cor_van_de_water XoIP +31 87 784 1130 tel:%2B31%2087%20784%201130 private: cvandewater.info www.proxim.com This email message (including any attachments) contains confidential and proprietary information of Proxim Wireless Corporation. If you received this message in error, please delete it and notify the sender. Any unauthorized use, disclosure, distribution, or copying of any part of this message is prohibited. -Original Message- From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of David Nelson via EV Sent: Friday, June 19, 2015 4:37 PM To: Bill Dube; Electric Vehicle Discussion List Subject: Re: [EVDL] Zero self-discharge (was: Bicycle battery) Bill, I have dug through many scientific papers on Li batteries and how they work and I haven't been able to find anything about a theoretical self-discharge mechanism. I have found some explicitly talking about the lack of a charge shuttle mechanism like in lead-acid batteries, however. One paper I read has a section devoted to figuring out a charge shuttle mechanism to add to a Li cell. It isn't a paper for the faint of heart, however. It is Nonaqueous Liquid Electrolytes for Lithium-Based Rechargeable Batteries by Kang Xu published in the Chemical Review, 2004, Vol. 104, No. 10, pp. 4303-4417 and published on the web 09/16/2004. While I'm sure I don't get it 100% of the time I try to make sure I say, LiFePO4 cells have no theoretical self discharge mechanism. This, according to all I have been able to find on the cells, is true. Also, the most ardent anti-BMS people I have found have in fact done a lot of searching of the scientific literature and came to the same conclusion. It was not just something they made up to support their anti-BMS position. If you have other literature showing what the self-discharge mechanism is please share it. On Fri, Jun 19, 2015 at 11:46 AM, Bill Dube via EV ev@lists.evdl.org wrote: This zero self-discharge myth seems to be a common thread with the anti-BMS crowd. I don't know where this misinformation comes from. All cells have self-discharge. It is just a matter of degree. Also, the self-discharge varies from cell to cell. That's why you need a BMS. These are well-documented facts for all those that care to investigate, either through the scientific literature or by simply systematically testing cells for themselves (as Lee Hart has done.) I strongly suspect the zero self-discharge myth comes from the same unscientific source that the anti-BMS myth has sprung from. Bill D. ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) -- David D. Nelson http://evalbum.com/1328 http://www.levforum.com ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html
Re: [EVDL] Zero self-discharge
Michael Ross via EV wrote: I think it is very valuable knowing that a Li ion cell can hold its charge indefinitely. Particularly compared to the incumbent competitor - lead acid cells. There is a least an implication that the the loses may be of no consequence after design and manufacturing improvements. There is no possibility of achieving this ever with lead acid. Surprisingly, that's not entirely the case. The self-discharge rate of a battery is usually traded off with many other parameters; capacity, life, peak current, etc. For most lead-acid batteries, the market considers factors other than self-discharge to be a *lot* more important. But, there are exceptions. I just pulled some Gates Cyclon spiral-wound lead-acid gel cell off the shelf. They were purchased in Nov 1994, and used for 5 years in electric lawn mower. My notes say the last time they were charged was on Nov 14, 2000. At that time, they still had about 1.5ah of capacity (out of their original 2.5ah). Today, 4 out of 13 *still* have charge in them (1.9v or more open circuit). One reason for this is that Gates used *pure* virgin lead; not a lead alloy. Almost all other lead-acid batteries alloy the lead with antimony, calcium, cobalt, or just the random mix of junk left over in scrap lead. Or, someone will have watered the battery with tap water, which adds its own unknown impurities. All this stuff worsens the self-discharge characteristics. But that doesn't matter to most customers; they will be recharging the battery often enough so it never runs dead. If you care, Gates was bought out by GE, who sold out to Hawker, who is now owned by Enersys. So you can still buy these Cyclons today! But they have an insignificant market, because (almost) no one cares about self-discharge. On Fri, Jun 19, 2015 at 8:11 PM, Cor van de Water via EVev@lists.evdl.org wrote: David, Why do all manufacturers of Li-Ion batteries specify the amount of self-discharge and why do people like me who monitor Li-Ion batteries over time, see and measure the self-discharge? I understand that you say theoretical the pure Li-Ion cell may not have a self discharge mechanism and thus the actual present self-discharge appears to be a spurious effect, possibly caused by contamination, so the amount of self-discharge is a quality indicator of the (lack of) contamination in the cell... However, saying that the ideal (theoretical) cell does not have any self-discharge is as valuable as saying that the ideal (theoretical) connection does not have any resistance. In practice however you better take that resistance into account when sizing your wiring and connections. Similar to taking self-discharge (and especially the difference in self-discharge between cells) into account when designing a battery pack. Cor van de Water Chief Scientist Proxim Wireless office +1 408 383 7626 Skype: cor_van_de_water XoIP +31 87 784 1130 private: cvandewater.info www.proxim.com This email message (including any attachments) contains confidential and proprietary information of Proxim Wireless Corporation. If you received this message in error, please delete it and notify the sender. Any unauthorized use, disclosure, distribution, or copying of any part of this message is prohibited. -Original Message- From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of David Nelson via EV Sent: Friday, June 19, 2015 4:37 PM To: Bill Dube; Electric Vehicle Discussion List Subject: Re: [EVDL] Zero self-discharge (was: Bicycle battery) Bill, I have dug through many scientific papers on Li batteries and how they work and I haven't been able to find anything about a theoretical self-discharge mechanism. I have found some explicitly talking about the lack of a charge shuttle mechanism like in lead-acid batteries, however. One paper I read has a section devoted to figuring out a charge shuttle mechanism to add to a Li cell. It isn't a paper for the faint of heart, however. It is Nonaqueous Liquid Electrolytes for Lithium-Based Rechargeable Batteries by Kang Xu published in the Chemical Review, 2004, Vol. 104, No. 10, pp. 4303-4417 and published on the web 09/16/2004. While I'm sure I don't get it 100% of the time I try to make sure I say, LiFePO4 cells have no theoretical self discharge mechanism. This, according to all I have been able to find on the cells, is true. Also, the most ardent anti-BMS people I have found have in fact done a lot of searching of the scientific literature and came to the same conclusion. It was not just something they made up to support their anti-BMS position. If you have other literature showing what the self-discharge mechanism is please share it. On Fri, Jun 19, 2015 at 11:46 AM, Bill Dube via EVev@lists.evdl.org wrote: This zero self-discharge myth seems to be a common thread with the anti-BMS crowd. I don't know where this misinformation comes from. All cells have self-discharge
Re: [EVDL] Zero self-discharge
Thanks Lee, that is neat to know. I freely admit having little understanding of lead acid. On Sat, Jun 20, 2015 at 1:15 PM, Lee Hart via EV ev@lists.evdl.org wrote: Michael Ross via EV wrote: I think it is very valuable knowing that a Li ion cell can hold its charge indefinitely. Particularly compared to the incumbent competitor - lead acid cells. There is a least an implication that the the loses may be of no consequence after design and manufacturing improvements. There is no possibility of achieving this ever with lead acid. Surprisingly, that's not entirely the case. The self-discharge rate of a battery is usually traded off with many other parameters; capacity, life, peak current, etc. For most lead-acid batteries, the market considers factors other than self-discharge to be a *lot* more important. But, there are exceptions. I just pulled some Gates Cyclon spiral-wound lead-acid gel cell off the shelf. They were purchased in Nov 1994, and used for 5 years in electric lawn mower. My notes say the last time they were charged was on Nov 14, 2000. At that time, they still had about 1.5ah of capacity (out of their original 2.5ah). Today, 4 out of 13 *still* have charge in them (1.9v or more open circuit). One reason for this is that Gates used *pure* virgin lead; not a lead alloy. Almost all other lead-acid batteries alloy the lead with antimony, calcium, cobalt, or just the random mix of junk left over in scrap lead. Or, someone will have watered the battery with tap water, which adds its own unknown impurities. All this stuff worsens the self-discharge characteristics. But that doesn't matter to most customers; they will be recharging the battery often enough so it never runs dead. If you care, Gates was bought out by GE, who sold out to Hawker, who is now owned by Enersys. So you can still buy these Cyclons today! But they have an insignificant market, because (almost) no one cares about self-discharge. On Fri, Jun 19, 2015 at 8:11 PM, Cor van de Water via EV ev@lists.evdl.org wrote: David, Why do all manufacturers of Li-Ion batteries specify the amount of self-discharge and why do people like me who monitor Li-Ion batteries over time, see and measure the self-discharge? I understand that you say theoretical the pure Li-Ion cell may not have a self discharge mechanism and thus the actual present self-discharge appears to be a spurious effect, possibly caused by contamination, so the amount of self-discharge is a quality indicator of the (lack of) contamination in the cell... However, saying that the ideal (theoretical) cell does not have any self-discharge is as valuable as saying that the ideal (theoretical) connection does not have any resistance. In practice however you better take that resistance into account when sizing your wiring and connections. Similar to taking self-discharge (and especially the difference in self-discharge between cells) into account when designing a battery pack. Cor van de Water Chief Scientist Proxim Wireless office +1 408 383 7626 Skype: cor_van_de_water XoIP +31 87 784 1130 private: cvandewater.info www.proxim.com This email message (including any attachments) contains confidential and proprietary information of Proxim Wireless Corporation. If you received this message in error, please delete it and notify the sender. Any unauthorized use, disclosure, distribution, or copying of any part of this message is prohibited. -Original Message- From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of David Nelson via EV Sent: Friday, June 19, 2015 4:37 PM To: Bill Dube; Electric Vehicle Discussion List Subject: Re: [EVDL] Zero self-discharge (was: Bicycle battery) Bill, I have dug through many scientific papers on Li batteries and how they work and I haven't been able to find anything about a theoretical self-discharge mechanism. I have found some explicitly talking about the lack of a charge shuttle mechanism like in lead-acid batteries, however. One paper I read has a section devoted to figuring out a charge shuttle mechanism to add to a Li cell. It isn't a paper for the faint of heart, however. It is Nonaqueous Liquid Electrolytes for Lithium-Based Rechargeable Batteries by Kang Xu published in the Chemical Review, 2004, Vol. 104, No. 10, pp. 4303-4417 and published on the web 09/16/2004. While I'm sure I don't get it 100% of the time I try to make sure I say, LiFePO4 cells have no theoretical self discharge mechanism. This, according to all I have been able to find on the cells, is true. Also, the most ardent anti-BMS people I have found have in fact done a lot of searching of the scientific literature and came to the same conclusion. It was not just something they made up to support their anti-BMS position. If you have other literature showing what the self-discharge mechanism is please share it. On Fri
Re: [EVDL] Zero self-discharge (was: Bicycle battery)
Bill, I have dug through many scientific papers on Li batteries and how they work and I haven't been able to find anything about a theoretical self-discharge mechanism. I have found some explicitly talking about the lack of a charge shuttle mechanism like in lead-acid batteries, however. One paper I read has a section devoted to figuring out a charge shuttle mechanism to add to a Li cell. It isn't a paper for the faint of heart, however. It is Nonaqueous Liquid Electrolytes for Lithium-Based Rechargeable Batteries by Kang Xu published in the Chemical Review, 2004, Vol. 104, No. 10, pp. 4303-4417 and published on the web 09/16/2004. While I'm sure I don't get it 100% of the time I try to make sure I say, LiFePO4 cells have no theoretical self discharge mechanism. This, according to all I have been able to find on the cells, is true. Also, the most ardent anti-BMS people I have found have in fact done a lot of searching of the scientific literature and came to the same conclusion. It was not just something they made up to support their anti-BMS position. If you have other literature showing what the self-discharge mechanism is please share it. On Fri, Jun 19, 2015 at 11:46 AM, Bill Dube via EV ev@lists.evdl.org wrote: This zero self-discharge myth seems to be a common thread with the anti-BMS crowd. I don't know where this misinformation comes from. All cells have self-discharge. It is just a matter of degree. Also, the self-discharge varies from cell to cell. That's why you need a BMS. These are well-documented facts for all those that care to investigate, either through the scientific literature or by simply systematically testing cells for themselves (as Lee Hart has done.) I strongly suspect the zero self-discharge myth comes from the same unscientific source that the anti-BMS myth has sprung from. Bill D. ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) -- David D. Nelson http://evalbum.com/1328 http://www.levforum.com ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Zero self-discharge (was: Bicycle battery)
David, Here is a paper describing the chemical and physical mechanisms inside a Li-Ion cell that cause self-discharge. Happy reading! http://www.che.sc.edu/faculty/popov/drbnp/WebSite/MSA-calendar.pdf Regards, Cor van de Water Chief Scientist Proxim Wireless office +1 408 383 7626 Skype: cor_van_de_water XoIP +31 87 784 1130 private: cvandewater.info www.proxim.com This email message (including any attachments) contains confidential and proprietary information of Proxim Wireless Corporation. If you received this message in error, please delete it and notify the sender. Any unauthorized use, disclosure, distribution, or copying of any part of this message is prohibited. -Original Message- From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of David Nelson via EV Sent: Friday, June 19, 2015 4:37 PM To: Bill Dube; Electric Vehicle Discussion List Subject: Re: [EVDL] Zero self-discharge (was: Bicycle battery) Bill, I have dug through many scientific papers on Li batteries and how they work and I haven't been able to find anything about a theoretical self-discharge mechanism. I have found some explicitly talking about the lack of a charge shuttle mechanism like in lead-acid batteries, however. One paper I read has a section devoted to figuring out a charge shuttle mechanism to add to a Li cell. It isn't a paper for the faint of heart, however. It is Nonaqueous Liquid Electrolytes for Lithium-Based Rechargeable Batteries by Kang Xu published in the Chemical Review, 2004, Vol. 104, No. 10, pp. 4303-4417 and published on the web 09/16/2004. While I'm sure I don't get it 100% of the time I try to make sure I say, LiFePO4 cells have no theoretical self discharge mechanism. This, according to all I have been able to find on the cells, is true. Also, the most ardent anti-BMS people I have found have in fact done a lot of searching of the scientific literature and came to the same conclusion. It was not just something they made up to support their anti-BMS position. If you have other literature showing what the self-discharge mechanism is please share it. On Fri, Jun 19, 2015 at 11:46 AM, Bill Dube via EV ev@lists.evdl.org wrote: This zero self-discharge myth seems to be a common thread with the anti-BMS crowd. I don't know where this misinformation comes from. All cells have self-discharge. It is just a matter of degree. Also, the self-discharge varies from cell to cell. That's why you need a BMS. These are well-documented facts for all those that care to investigate, either through the scientific literature or by simply systematically testing cells for themselves (as Lee Hart has done.) I strongly suspect the zero self-discharge myth comes from the same unscientific source that the anti-BMS myth has sprung from. Bill D. ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) -- David D. Nelson http://evalbum.com/1328 http://www.levforum.com ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Zero self-discharge (was: Bicycle battery)
Cor, There is no author, no date, no publisher, no prior art, and no references. Was it in a journal, is the peer review? Has it been repeated? Is there a more complete copy or a place where it can be purchased? On Fri, Jun 19, 2015 at 8:58 PM, Cor van de Water via EV ev@lists.evdl.org wrote: David, Here is a paper describing the chemical and physical mechanisms inside a Li-Ion cell that cause self-discharge. Happy reading! http://www.che.sc.edu/faculty/popov/drbnp/WebSite/MSA-calendar.pdf Regards, Cor van de Water Chief Scientist Proxim Wireless office +1 408 383 7626 Skype: cor_van_de_water XoIP +31 87 784 1130 private: cvandewater.info www.proxim.com This email message (including any attachments) contains confidential and proprietary information of Proxim Wireless Corporation. If you received this message in error, please delete it and notify the sender. Any unauthorized use, disclosure, distribution, or copying of any part of this message is prohibited. -Original Message- From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of David Nelson via EV Sent: Friday, June 19, 2015 4:37 PM To: Bill Dube; Electric Vehicle Discussion List Subject: Re: [EVDL] Zero self-discharge (was: Bicycle battery) Bill, I have dug through many scientific papers on Li batteries and how they work and I haven't been able to find anything about a theoretical self-discharge mechanism. I have found some explicitly talking about the lack of a charge shuttle mechanism like in lead-acid batteries, however. One paper I read has a section devoted to figuring out a charge shuttle mechanism to add to a Li cell. It isn't a paper for the faint of heart, however. It is Nonaqueous Liquid Electrolytes for Lithium-Based Rechargeable Batteries by Kang Xu published in the Chemical Review, 2004, Vol. 104, No. 10, pp. 4303-4417 and published on the web 09/16/2004. While I'm sure I don't get it 100% of the time I try to make sure I say, LiFePO4 cells have no theoretical self discharge mechanism. This, according to all I have been able to find on the cells, is true. Also, the most ardent anti-BMS people I have found have in fact done a lot of searching of the scientific literature and came to the same conclusion. It was not just something they made up to support their anti-BMS position. If you have other literature showing what the self-discharge mechanism is please share it. On Fri, Jun 19, 2015 at 11:46 AM, Bill Dube via EV ev@lists.evdl.org wrote: This zero self-discharge myth seems to be a common thread with the anti-BMS crowd. I don't know where this misinformation comes from. All cells have self-discharge. It is just a matter of degree. Also, the self-discharge varies from cell to cell. That's why you need a BMS. These are well-documented facts for all those that care to investigate, either through the scientific literature or by simply systematically testing cells for themselves (as Lee Hart has done.) I strongly suspect the zero self-discharge myth comes from the same unscientific source that the anti-BMS myth has sprung from. Bill D. ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) -- David D. Nelson http://evalbum.com/1328 http://www.levforum.com ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA ( http://groups.yahoo.com/group/NEDRA) ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA ( http://groups.yahoo.com/group/NEDRA) -- To invent, you need a good imagination and a pile of junk. Thomas A. Edison http://www.brainyquote.com/quotes/quotes/t/thomasaed125362.html A public-opinion poll is no substitute for thought. *Warren Buffet* Michael E. Ross (919) 585-6737 Land (919) 576-0824 https://www.google.com/voice/b/0?pli=1#phones Google Phone (919) 631-1451 Cell michael.e.r...@gmail.com michael.e.r...@gmail.com -- next part -- An HTML attachment was scrubbed... URL: http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150619/32fcebff/attachment.htm ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Zero self-discharge (was: Bicycle battery)
Did actually read it? That paper is about capacity loss not voltage drop over time. Sent from my iPad On Jun 19, 2015, at 7:58 PM, Cor van de Water via EV ev@lists.evdl.org wrote: David, Here is a paper describing the chemical and physical mechanisms inside a Li-Ion cell that cause self-discharge. Happy reading! http://www.che.sc.edu/faculty/popov/drbnp/WebSite/MSA-calendar.pdf Regards, Cor van de Water Chief Scientist Proxim Wireless office +1 408 383 7626Skype: cor_van_de_water XoIP +31 87 784 1130private: cvandewater.info www.proxim.com This email message (including any attachments) contains confidential and proprietary information of Proxim Wireless Corporation. If you received this message in error, please delete it and notify the sender. Any unauthorized use, disclosure, distribution, or copying of any part of this message is prohibited. -Original Message- From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of David Nelson via EV Sent: Friday, June 19, 2015 4:37 PM To: Bill Dube; Electric Vehicle Discussion List Subject: Re: [EVDL] Zero self-discharge (was: Bicycle battery) Bill, I have dug through many scientific papers on Li batteries and how they work and I haven't been able to find anything about a theoretical self-discharge mechanism. I have found some explicitly talking about the lack of a charge shuttle mechanism like in lead-acid batteries, however. One paper I read has a section devoted to figuring out a charge shuttle mechanism to add to a Li cell. It isn't a paper for the faint of heart, however. It is Nonaqueous Liquid Electrolytes for Lithium-Based Rechargeable Batteries by Kang Xu published in the Chemical Review, 2004, Vol. 104, No. 10, pp. 4303-4417 and published on the web 09/16/2004. While I'm sure I don't get it 100% of the time I try to make sure I say, LiFePO4 cells have no theoretical self discharge mechanism. This, according to all I have been able to find on the cells, is true. Also, the most ardent anti-BMS people I have found have in fact done a lot of searching of the scientific literature and came to the same conclusion. It was not just something they made up to support their anti-BMS position. If you have other literature showing what the self-discharge mechanism is please share it. On Fri, Jun 19, 2015 at 11:46 AM, Bill Dube via EV ev@lists.evdl.org wrote: This zero self-discharge myth seems to be a common thread with the anti-BMS crowd. I don't know where this misinformation comes from. All cells have self-discharge. It is just a matter of degree. Also, the self-discharge varies from cell to cell. That's why you need a BMS. These are well-documented facts for all those that care to investigate, either through the scientific literature or by simply systematically testing cells for themselves (as Lee Hart has done.) I strongly suspect the zero self-discharge myth comes from the same unscientific source that the anti-BMS myth has sprung from. Bill D. ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) -- David D. Nelson http://evalbum.com/1328 http://www.levforum.com ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
