magudaman
10 kW
LifePo4 is lithium and doesn't suffer from the same problems at high SOC as other lithium chemistries
Working on LiFePO4 36 volt pack
- Thread starter erdurbin
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xyster
10 MW
magudaman said:
There's no solid evidence yet I'm aware of one way or the other. Since it's still lithium ions shuttling about, I assume the same rules apply, and LiFePO4 just degrades slower at all states-of-charge compared to other lithium chemistries -- but still degrades faster when fully charged or fully discharged compared to when used and stored somewhere in the middle.
magudaman
10 kW
This maybe getting your information from direct from the propaganda presses but what I was thinking of was the internal resistance increase of normal cell that I believe results in capacity and efficiency losses are show to remain the same with a123's cells. You can check it out here:
http://www.a123systems.com/newsite/index.php#/technology/power/pchart4/
http://www.a123systems.com/newsite/index.php#/technology/power/pchart4/
xyster
10 MW
magudaman said:
Interesting. Their capacity versus cycle chart now claims 7,000 cycles to 80% capacity at 100% DoD.
http://www.a123systems.com/newsite/index.php#/technology/life/lchart1/
They used to claim 2000 cycles.
They also claim 1000 cycles at 60 celsius:
http://www.a123systems.com/newsite/index.php#/technology/life/lchart3/
There's little doubt these cells are a breakthrough in secondary cell longevity. But it's still an open question if the cells degrade slower when operated and stored between the extremes of charge and discharge. Also unknown is how time effects capacity. I didn't see any charts about that. And of course none of this has been corroborated yet by the obligatory mess of independent tests.
If the pampered A123 cell is good for 100,000 cycles and 100 years, then some of us might be bequeathing our packs to our children, who won't want them or know what to do with them because dilithium crystal powered hoverboards are all the rage.
