They say it's "lithium ion ferrous phosphate" in this Fortune article reproduced on their site:
http://www.byd.com/buzz/media-reproduced/warren-buffett-takes-charge/ BYD LiPO4 batteries equip OLPC (one laptop per child) laptops, see: http://wiki.laptop.org/go/Laptop_Batteries#BYD_LiFePO4 so they must be reasonably inexpensive. I was surprised to see on that page that they work on a wider temperature range than NiMH! Michel 2009/9/15 <mix...@bigpond.com>: > In reply to Michel Jullian's message of Mon, 14 Sep 2009 12:19:30 +0200: > Hi Michel, > [snip] >>Hi Robin, see here: >> >>http://en.wikipedia.org/wiki/Rechargeable_battery#Table_of_rechargeable_battery_technologies >> > > Thanks, that's very useful. :) However how do you know that the Fe ion > technology mentioned is in fact referring to LiFePO4? > >>Energy density of LiFePO4 is not as good as Li ion (0.1 kWh/Kg vs 0.16 >>kWh/Kg), which means their 72 kWh battery must weigh 720Kg --which may >>not be much of a problem since EVs have regenerative braking--, but >>cycle life is better (2000 cycles vs 1200 cycles). >> >>I also gather cost per kWh of capacity is lower. I seem to recall >>reading USD 300 per kWh, which would account for about half of the >>USD 40000 projected price of the car (300*72 = 21600). This would be >>about USD 100 per cycle, i.e. USD 100 for 400km, i.e. USD 0.25 per km >>or USD 0.40 per mile of battery wear out, this seems reasonable, >>what's the wear out cost for an ICE of equivalent output power anyone >>knows? >> >>Michel > [snip] > Regards, > > Robin van Spaandonk > > http://rvanspaa.freehostia.com/Project.html > >
