I'm the one that originally posted that video and he doesn't make any such claim in it.
________________________________ From: Michael Ross via EV <ev@lists.evdl.org> To: Bill Dube <billd...@killacycle.com>; Electric Vehicle Discussion List <ev@lists.evdl.org> Sent: Wednesday, April 1, 2015 2:23 PM Subject: Re: [EVDL] Temperature rating (Was: ENERDEL Battery Experiences) "The 104 F (40 C) limit applies somewhat equally to all Li-ion chemistries. The temperature is limited because the electrolyte boils just slightly above that temperature. Same type of electrolyte in all Li-ion chemistries thus the same limit." Hi Bill, With all due respect this is not the failure I have been alluding to. It is the reaction that occurs when a fully delithiated anode at elevated temperature starts tearing up the electrolyte. According to the fellows at Dalhousie this what kills cells that otherwise are capable of decent life. In other words disregarding deficiencies in design that cause failure, concentrating on what happens to the basic constituents of the cells. A good place to start: https://www.youtube.com/watch?v=pxP0Cu00sZs This will also elaborate on the very great variety of electrolytes that are used. The same type of electrolytes are NOT used in all Li ion chemistries. They ARE mostly organic carbonates, so what you said is true in a very basic sense, but there is a lot of blending and additive use that is important, particularly for cycle life. This is relatively new information that is only realized with HPC testing. Mike On Wed, Apr 1, 2015 at 2:13 PM, Bill Dube via EV <ev@lists.evdl.org> wrote: > The 104 F (40 C) limit applies somewhat equally to all Li-ion chemistries. > The temperature is limited because the electrolyte boils just slightly > above that temperature. Same type of electrolyte in all Li-ion chemistries > thus the same limit. > > The cell containment vessel can make a big difference in this > temperature limit, however. Cylindrical cells can often hold significant > pressure while prismatic and pouch cells can withstand less or perhaps no > pressure. Life a pressure cooker, the higher the pressure of the > electrolyte, the higher temperature you can withstand. The A123 26650M1 > cells (LiFePO4) would withstand up to 100 Celsius (yes that is correct) > without damage. They weren't "rated" that high, but they could withstand > that temperature. They were rated for 60 Celsius (140 F). > > Keep in mind that the cells will age much more rapidly at that > elevated temperature. They perform better, however, and you don't hold them > that hot for very long. You must choose the compromise between total > life-span and performance for the specific application, which is typical > for most things in life. > > I'm not sure where you are getting your information. Better check > more than one source. > > Bill D. > > At 10:42 AM 4/1/2015, you wrote: > >> Jeff, I am not sure why performance at ambient temperatures should make >> anyone feel confident about a cell. LFP for instance, starts to have >> serious difficulties at 104°F if it is fully charged. That is certainly >> ambient here in North Carolina; and that is free air, not boxed up with >> significant amperage scooting about. I must tell you, I don't have an axe >> to grind here. I simply want to point out a better way to go. That is to >> get better information for all. And better testing with in the industry. >> ENERDEL just popped up on my radar is all. They have an website that is >> light on good information and I waded in. I am happy to see that behind >> the curtain they may have more on the ball. I have been scanning the course >> work you provided to me, and it is very nice. When ENERDEL discusses cycle >> life (around page 279) I can see they clearly understand the reactivity of >> the positive electrode at very high SOC and how temperature makes that much >> worse for the electrolyte. They clearly have good information to work with >> and probably are engaged with Dalhousie University or the spin off Novonix >> to get good testing done. I am duly impressed. I still have not figured >> out what chemistry they have chosen. From what I have seen so far, they >> speak assiduously, only in general terms regarding their own cells. If >> they are using some inferior chemistry and electrolyte package it is >> clearly not because they don't know better, so I bet they are OK. >> Provisional blessing on them until I am better educated. Thanks for taking >> the time to address this with me. Mike On Wed, Apr 1, 2015 at 10:19 AM, >> Jeff Major via EV <ev@lists.evdl.org> wrote: > I doubt that EnerDel and >> its customers have overlooked anything as basic > as performance and life >> at ambient temperatures. It appears to me that > Hoegberg is comparing to >> some float stand-by application and then > misinterpreting the presented >> data. But whatever. They have millions of > cells in the field and no >> complaints of which I am aware. > > -------------- next part -------------- >> > An HTML attachment was scrubbed... > URL: < > >> http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/ >> 20150401/e6911ad9/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) > >> > -- 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... 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