WIllie2 and I were having a back channel about this topic. Willie was thinking that LFP had a voltage simnilar to other chemistries. I thought others might want to see this too.
Here is what the Handbook of Batteries 4th Ed. says. From Table 26.3 Characteristics of Some Positive Electrode Materials: Order of entries: Material, Specific Capacity (mAh/g), MIdpoint Voltage vs. Li at C/20, Comments *LiCoO(2) (LCO) 155, 3.9 * Most common, Co expensive =>$ *LiNi(1-x-y)Mn(x)Co(y)O(2) (NMC), 140 -180, ~3.8 * Safer, =<$, capacity depends on upper cutoff V *LiNi(0.8)Co(0.15)Al(0.05)O(2), 200, 3.75 * Safe as LCO, high capacity (Tesla?) *LiMn(2)O(4), 100 - 120, 4.05 * =<$, Safer than LCO, poor temp stability *LiFePO(4) (LFP), 160, 3.45 * Very safe, low volumetric energy, processed in inert gas =>$ process *Li[Li(1/9)Ni(1/3)Mn(5/9)]O(2), 275 3.8* High specific capacity, low rate capability, R&D scale only *LiNi(0.5)Mn(1.5)O(4), 130, 4.6* Requires electrolyte that is stable at high voltage This raises some questions for me. They are trying to be very careful how they describe and compare voltages. I am not clear on how they do it - versus LI? What is that exactly. I do understand that it is tricky because each chemistry has a different look to its curve; so what is a valid way to do it? I think he must have chosen the particular anode materials to show a range of properties rather than to be comprehensive. He made careful distinctions between the anode formulations. Not being an electrochemist I can't say I understand the meaning of the various x and y, decimal and fractional proportions. I read so much stuff casually...I am pretty sure Tesla uses the LiNiCoAlO (I call it NCA) the high capacity on by weight, and that makes sense as they were trying to answer the range anxiety business as best they could. I will link again to this paper that is nice overview of various chemistries, it is getting a litttle long in the tooth though. https://www.bcg.com/documents/file36615.pdf On Fri, Mar 27, 2015 at 9:49 AM, Michael Ross <michael.e.r...@gmail.com> wrote: > I don't think that is correct about the the voltage. I will look around. > LFP to my recollection is notably lower than the other chemistries as it is > not a Li metal oxide. It is a Li metal phosphate. Let my get out the > handbook. > > On Fri, Mar 27, 2015 at 9:35 AM, Willie2 <wmckem...@gmail.com> wrote: > >> On 03/27/2015 08:04 AM, Michael Ross wrote: >> >> *"I was expecting similar or better performance on the Leaf battery."* >> >> As far as I can tell that was an unwarranted assumption. >> >> If anything is true, it is certain that LFP are an outlier in behavior >> to the other chemistries that have Li metal oxide positive electrodes. I >> heard Jack Rickard claim he knows what the chemistry of t a Leaf cells are, >> but it wasn't from a spec sheet. Does anyone know for certain? I heard a >> professor working on cell design claim Tesla was using LFP, but is clearly >> no long correct, if it ever was. Misinformation abounds. >> >> Early on, I read that Leafs were using LiMn, about the same voltage as >> LFP, ~3.2. Tesla's laptop cells are clearly LiCo, ~3.7v. Granted, there >> are vast and significant differences within all chemistries. It was their >> LiCo cells that gave ThunderSky such a bad reputation before about 2007. >> >> ThunderSky used to offer LiMn prismatic cells as well as LFP. The LiMn >> were rated at ~800 cycles while the LFPs were 2000-4000. This is from the >> era when I was shopping for very early lithium cells for a conversion, >> about 2007. I recall being very wary of Leafs when I first heard they were >> LiMn. I finally accepted that "Nissan must know what they are doing". >> Wrong, I was. >> >> On the other hand, I was very wary of Tesla's cells because of the known >> fire hazard. Wrong again. At least, so far. >> >> I wonder what became of Jukka? He should be commenting here. >> >> >> >> > > > -- > 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/20150327/78b298f4/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)
