Lithium-ion vs. nickel-metal hydride: Toyota still likes both for its hybrids Well here’s your answer.
Their thinking is sound. They got a supply for NiMH well secured, and the Li-ion one is still growing to meet demand. Toyota's electric AWD systems aren't designed for off road use, but for emergency traction on roads. Rain alone can make a road slippery, but slippery conditions are more likely when it is colder as things freeze. Batteries work the best within a temperature range. Outside that, and performance drops. For an EV, that means less power, slower acceleration, and less regenerative braking. Part off the efficiency loss seen in a hybrid during a hot summer and cold winter is because of the battery not being within its ideal temperature range. Then as with being too hot, being too cold could damage the battery. Plug ins use supplemental heaters to keep their Li-ion from getting too cold for that reason. NiMH can perform better than Li-ion at low temperatures, and operate at temperatures which are damaging to it. In Japan, roads don't get salted, so much of the AWD sales go to areas that see snow and ice. It makes sense to put NiMH in eAWD hybrids then. Especially since Toyota sized the Li-ion packs for easy swapping with NiMH, lighter weight, and not increased EV performance.
then they should put nimh in all the prius sold in the northeast and etc., lots of aid cars around here
