Do you have a reference JRP3? Would be nice to know what they use for certain, so I can stop prefacing with "I think."I think both the Volt and LEAF use LiMn chemistry of some form.
http://spectrum.ieee.org/green-tech...-allelectric-leaf-doesnt-stint-on-performanceNissan’s new batteries consist instead of sheets of lithium manganese and graphite, stacked in waferlike cells, each about the size of a manila envelope. Four of these cells get packed into a box the size of a textbook. Nissan managed to fit 48 such boxes beneath the seat and under the floor. Simple airflow is enough to cool them. The battery can deliver 90 kW of power and has an energy capacity of 24 kWh, about twice that of Nissan’s previous lithium-ion batteries of the same size. And Nissan’s already working on a version with a lithium nickel manganese cobalt oxide cathode, which might double again the battery’s capacity.
Search Youtube for 'Chevy Volt Battery Deep Dive' and they talk about LG Chem and their Lithium Manganese cells. They show pictures of the cell balancers installed and the pack itself outside of the car, it's capacity, how the capacity is used, stuff like that. Ford and Hyundai have both discussed their LG Chem battery packs as well, different configuration but seem to be using the same thermal coolant jacket sandwiched between every 2 cells(so one side of every cell is in contact with heat exchange) that I presume was designed by LG Chem.Do you have a reference JRP3? Would be nice to know what they use for certain, so I can stop prefacing with "I think."
I attended a presentation by the then head of technology at Altairnano in early 2008. He claimed that the principle advantage of lithium titanate was the lithium ions could move through it without strain. He claimed they had demonstrated over 20,000 cycles, operation over much larger temperature range, and much higher power, though lower energy storage than most other lithium chemistries, and handed out brochures stating the same. They seem to be a strange company though. Never seem to go anywhere, and are very top heavy. He never returned my calls about using their cells in my car. The higher power is only really required by drag racers and the lower energy density is a real drawback. The much wider temperature range and much longer cycle life is appealing though.That's not entirely true, Wayland has tested Kokam's LiPo to 2K cycles I think, Altairnano's Li Titinate even higher, though they are more expensive.
All of the production EVs will be short cycled, the question is, to what extent.Of course GM is shallow cycling their pack so even a 1000 cycle cell will probably last far longer.
Yes their poor density really makes them a poor fit for passenger EV use. They are being used by Proterra in some buses, and they are trying to target grid applications such as frequency regulation where their fast charge/discharge ability and long cycle life are a real benefit and the poor density is not a problem. I think they are on the verge of being taken over by a Chinese company at this point.I attended a presentation by the then head of technology at Altairnano in early 2008. He claimed that the principle advantage of lithium titanate was the lithium ions could move through it without strain. He claimed they had demonstrated over 20,000 cycles, operation over much larger temperature range, and much higher power, though lower energy storage than most other lithium chemistries, and handed out brochures stating the same. They seem to be a strange company though. Never seem to go anywhere, and are very top heavy. He never returned my calls about using their cells in my car. The higher power is only really required by drag racers and the lower energy density is a real drawback. The much wider temperature range and much longer cycle life is appealing though.
The difference is that the Volt is locked in at only 50% pack capacity where the LEAF has the potential to use much more, though I agree that most daily use will shallow cycle the pack. Someone could use all of the LEAF's allowed capacity every day resulting in maybe 80-90% DOD, (don't know true pack size), a Volt owner can never do the same.All of the production EVs will be short cycled, the question is, to what extent.
LiPo cells, are you sure? I didn't think any production vehicles were going that route yet.Ford is apparently using lithium polymer from LG Chem (U.S. subsidiary Compact Power).