[ButchC]

All those things are true when comparing NiMH to NiCd but definitely not compared to lithium batteries. There's not a single metric for which you can't find a superior suitable lithium chemistry. Except for one: $Cost

Just Toyota doing Toyota things.

Also I would strongly disagree on the Prius comment. A lot of "HV battery fault" cars out there back in the day, refurbing them was a pretty good business for a while. The NiMH pack in the Prius was the basis for so many slack jawed comments "EVs will never work! You're just going to have to replace the battery every 5 years!"

[kube-system]

Cost, as you mentioned, is one reason. However they also fare better at extended temperature ranges and under long periods of self discharge. They are, generally speaking, more forgiving of a battery chemistry.

Your quote about rollout of the Prius is exactly my point. That opinion was widespread when the Prius was introduced. The reliability of the Prius since then has changed public opinion greatly.

[ButchC]

None of that makes any sense. What are you using as the basis for those statements? I feel like I'm hearing doublespeak where down is up.

NiMH infamously has HORRIBLE self discharge performance in comparison to pretty much any lithium chemistry.

Multiple lithium chemistries outperform NiMH in low temperature performance. Even LFP which is generally not recommended for unregulated conditions below about -10 degree will function at reduced capacity at -40c. Nearly all chemistries, except maybe LMO, have superior high temperature performance.

I also don't understand what you mean by more forgiving chemistry?

Production yields? Modern lithium cell plants can easily do 80%+

Tolerance to production variations? Multiple lithium chemistries are just as tolerant.

Fire/puncture resistance? Multiple lithium chemistries areas as safe or safer

Voltaic efficiency/Energy Efficiency/etc? Lithium chemistries are SIGNIFICANTLY better

Memory effect or reduced voltage? NIMH yes while lithium none

Cycle life? Once again nearly every lithium chemistry is superior. Some even still have acceptable performance after an order of magnitude more cycles than a NiMH cell.

At this point there is literally no reason someone would chose NiMH for a ground up design in a consumer vehicle other than cost ....seriously like none.

Also yes Prius reliability is pretty good, but the reliability and performance of the NiMH battery packs were not even in the range for what would be acceptable in a commercially successful EV.

At the time when commercial lithium batteries were $1000-$5000/kwh hour sure they were a fantastic compromise, but it's not even close now.

If Tesla had started with NiMH they would have been dead meat right out of the gate. Gone out of business in a couple years at most.

[kube-system]

I was comparing specifically to Li-Ion in the comment above. As to why major automakers are not using LiFePO4 or other chemistries in their cars, I don’t know, but it’s not anything that makes Toyota unique, which was what I was talking about.

There are, for sure, a tons of great lithium chemistries in existence. But, outside of some very specific markets, they are not used in cars yet.