Project Lithium NiMH to LiFePO4 conversion for Toyotas
 

This looks interesting. They claim it helps efficiency, longevity, reliability, etc. etc. etc., and that it has been tested in all sorts of extreme conditions.

https://projectlithium.com/

https://www.youtube.com/watch?v=8luIvtTGG6A

I can believe most of it

But on priuschat the Prius battery repair/swap guys are ****ting bricks because he isn’t answering their questions.

My main worry living in a climate that can drop to -40F is that the battery might become rapidly damaged in the cold

If he would offer a pack for a Gen 1 PRIUS or Insight I would buy one with a charger to evade this state’s excessive hybrid and plug in taxes

I have worked with LiFePO4 enough to know that when you cold start the car below a certain temperature the car is going to have to be gas only below 0F, then the battery can put out power but it will be extremely weak and no charging till the battery can warm up above +20F.

5 LiFePO4 cells fall within the voltage limits of one block of 12 cells for the NiMH Toyota BMS system, so voltage shouldn't be a problem. And as long as the cells are rated for the amperage that shouldn't be a problem either.

Thermals, mainly the cold, are what could be a major problem. It can hit -40°F(-40°C) here where I live too. Not that making a battery heater isn't impossible.

I wonder if it's possible to make an ultracapacitor pack that's small enough to be cost effective yet big enough to start the car and run in a pretty much gas-only mode. I do believe that in cold weather that's pretty much what my Toyota Hybrids do anyway since the NiMH seem to have very high resistance characteristics.

Balancing is also a question I'd have.

But ya, they guy seems to exagerate a bit.

On a somewhat similar topic, anyone know how Winston LiFePO4 cells do in the cold? They supposedly have added yttrium to help with the cold and are rated to -40°F (-40°C). I've thought about filling the back of my Prius up with 40AH Winston cells hooked up in blocks of 5 and directly replacing the NiMH cells. They are only rated at 120 amps which would be just on the limit of what the Prius will do.

Back 10 years over on DIYELECTRICCARS, Pete did a freeze test on some cells but I don't think they were Winstons. The results were impressive on how far the cells were throttled down. Below 0 they wouldn't even charge, and some were damaged just by being frozen.

I suppose it will be like Diesels @Minot ND, where if you want to run them that cold, they'd better be heated to start

On the other end is heat. Gen3 cooling system is complete and total garbage. When these things are routinely operating at 120-130°F with uneven/ineffective cooling, they're likely not going to last long.

I just watched the first 7:50 of that video. Already enough misinformation for me to never consider this; furthermore, any credibility that "The Hybrid Guy" might have had is completely gone.

What misinformation are you referring to?

1. Describe as "training" - it's clearly marketing.
2. 4X the power - maybe true. The vehicle will not utilize any more power than has been established by the NiMH power curves. SoC calculations are based on NiMH current, voltage and temperature and are not meaningful when applied to LFP.
3. 400A vs. 100A. Quoting burst discharge for high drain LFP (61C) vs. sustained NiMH currents (15C).
4. NiMH 70% efficiency - true when looking at 0 to 100% SoC. In the 40-80% SoC normal operating range of the Toyota hybrids, they have near 100% Coulombic efficiency.
5. 3X EV range. Might be true. Important to know that this is accomplished by consuming more of the capacity of the LFP battery resulting in a greater DoD and higher cycle wear.
6. Lower voltage drop is related to the prior item. Yes, it's a performance advantage, but it comes at a cycle life cost.
7. "Real results from real people" - who? Just a bunch of text on a screen.
8. "No toxic fumes" - While arguably the safest Lithium chemistry, claiming it is safer than NiMH is a stretch. The electrolyte and vapors emitted from failing/malfunctioning LFP are extremely dangerous. Vapors will mix with the moisture in your airways and produce hydrofluoric acid. Electrolyte in NiMH is NaOH and KOH blend. NONflammable, NONexplosive but HIGHLY caustic (very strong base), but not inherently poisonous. Gases produced from NiMH are hydrogen and/or oxygen. Conveniently fails to mention that NiMH packs haven't had vent tubes on them for 10 years.

https://www.youtube.com/watch?v=07BS6QY3wI8

Ya, some of those points I already knew. I also learned some too, so thanks!

From what I can tell the guy is quite the amateur who exaggerates a lot in an attempt to convince everyone. It does seem like he might be hiding something and trying to cover it over with exaggerations. Or he's just exaggerating to try to convince everyone.

But in the end, I don't see any real advantage of his product unless it had more capacity. If the lithium battery has less of an internal resistance it may soak up and let out more of it's capacity than the NiMH. But he doesn't explain how he knows that for sure.