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)
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