Used to be, I am out of touch, that less than 100°F and 100% SOC was a recipe for significant battery degradation. Not say they haven't solved this, but 5 year old cells would not be very good in this respect.
On Wed, Jul 8, 2020 at 8:06 PM Bill Dube via EV <[email protected]> wrote: > I don't think that LiFePO4 has made any remarkable gains in specific > energy. > > What LiFePO4 does have is spectacular cycle life. If manufactured with > some degree of care, you get 15,000+, 100% SOC, 1C cycles @ 25 Celsius > from LiFePO4 without going below 50% of the original capacity. They just > keep going and going.... You have to seal the case well enough to keep > air and water out, and use paste, separators, etc. that are also > reasonably free of water and air on the inside. > > Thus, a "million mile" battery has always be possible to make with > LiFePO4 cells. You just have to be motivated to use quality cells, and > to actually build it. You also need to be motivated to drive the car > that many miles. :-) > > 200 miles per charge, times 15,000 charge cycles = 3,000,000 miles. Even > at 5000 cycles, that run-of-the-mill LiFePO4 cells achieve, this gets > you a million miles. > > Bill D. > > > On 7/7/2020 7:43 PM, EVDL Administrator via EV wrote: > > While I was looking for other information a couple of days ago, I ran > across > > something on the web that surprised me. I didn't follow up at the time > and > > now I've lost track of where it was, but maybe someone else here knows > > something about it. > > > > The post or article I saw claimed that Tesla's supposedly-upcoming much- > > discussed "million mile battery" is lithium iron phosphate chemistry. > > > > LiFePO4 was something of an EV holy grail 15-20 years ago. Valence was > > offering their Saphion phosphate-based lithium modules around 2002. A123 > > was also an early LiFePO4 booster. Both claimed long cycle life and > > improved safety, and A123s were also known for ferocious specific power. > > > > When the cheap and cheerful Chinese low-power versions from Thundersky, > > CALB, and others started to appear in the States, a lot of them went > into EV > > conversions. You can find discussions about this in the EVDL archive > around > > 2006-2009. > > > > If memory serves, the main downside to LiFePO4 was specific energy. It > just > > wasn't as good as what cobalt and manganese based chemistries offered. > > > > I also seem to recall some kind of patent-related LiFePO4 problem. This > may > > have been the reason that hobbyists jumped on the cheap and cheerful > Chinese > > LiFePO4 cells from Thundersky, CALB, and the like. Again dredging up > from > > memory, I think that hose companies somehow (allegedly) made an end run > > around the patent and licensing concerns. > > > > Now, if I'm not mistaken, Tesla's development partner in the "million > mile > > battery" is a Chinese firm. That's ... uh ... interesting. > > > > So has the EV world rehabilitated lithium iron phosphate's reputation? > Has > > its specific energy problem been solved? What about licensing and > patents? > > > > David Roden, EVDL moderator & general lackey > > > > To reach me, don't reply to this message; I won't get it. Use my > > offlist address here : http://evdl.org/help/index.html#supt > > > > = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = > > A developed country is not a place where the poor have cars. > > It's where the rich use public transportation. > > > > -- Gustavo Petro > > = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = > > > > _______________________________________________ > > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > > ARCHIVE: http://www.evdl.org/archive/index.html > > INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org > > Please discuss EV drag racing at NEDRA ( > http://groups.yahoo.com/group/NEDRA) > > > > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > ARCHIVE: http://www.evdl.org/archive/index.html > INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org > Please discuss EV drag racing at NEDRA ( > http://groups.yahoo.com/group/NEDRA) > > -- Michael E. Ross (919) 585-6737 Land (919) 901-2805 Cell and Text (919) 576-0824 <https://www.google.com/voice/b/0?pli=1#phones> Tablet, Google Phone and Text -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20200708/7f0ab120/attachment.html> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub ARCHIVE: http://www.evdl.org/archive/index.html INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
