Back when I was looking into rechargeable batteries at work, it was the lithium-cobalt chemistries that were having the spontaneous combustion problem. Lithium-iron-phospate did not. There were many other varieties in between, most with varying degrees of cobalt in the mix. While LiFePO was safe, it didn't rank as well on cost and energy density, so it wasn't suitable for all Li-ion uses. My 'inside' information is now seriously outdated.
The oxygen atoms in a LiFePO4 cathod are tightly bound compared to other chemistries. With a run of the mill LiCoO2 battery you start to liberate oxygen at 252C. Add a flamible electrolyte and you've got fire. The biggest problem with LiFePO4 is patent encumbrance. There are three groups claiming this technology.
How does the new Li-ion battery cope with cold? I see many reports of EV, not allowing to regen, when battery is at freezing temperatures, but with EV you can precondition the battery while charging. Even with old Ni-Mh in Gen3 I experience lower power from the battery when it's sub 0 °C, from my observation with help of OBDII and android app, battery is not capable of giving out more than 8 kW when cold, it could be that 7 years did put a little degradation on the battery. So, any experience, I know that Li-ion cells can be very different, I I'm just asking what did Toyota cook
I know there were some press tests in snowy New York last year with no issues. The lower trim US Prius and all Canadian ones have the NiMH battery. I believe Toyota stated the newer battery could have issues below 0F.
I work with batteries and lithium ones as well. We weld packs together for use in Airplanes. The main problem with fires and what happened when all the Fiskers were catching fire is poor manufacturing. The Hoover board is a prime example. When they short out is when you see fires. You would be amazed how hot just a few AA cells can get when they short out let alone a battery pack in a car or plane. There is serious quality control in automotive battery packs. Cheap Hooverboards and toys are considered class 1 products and are not made to last. Can't compare them to quality built battery packs.
Think thermal management. Hoover boards have none. Most laptops do, they have thermal sensors in the pack, so even microsoft can't make them break. The prius has very good thermal management, Based on pack temperature, it regulates the fan speed. If the pack temperature reaches a certain set point, the prius disconnects the battery and runs on ICE, until the batteries return to operating temperature.
Actually yes. Toys are class 1 something like a laptop is considered a class 2 product such as extended life performance that isn't critical. Class 3 is lifesaving devices such as medical equipment that performance is critical.
I think the lion batteries are a good step forward. The overheating, fires, etc, in my opinion has been inefficient control circuitry. Cutting the costs, etc lead to these types of problems. I have confidence in Toyota to build in the kind of safety control this battery needs under load working in various conditions.
The LiIon battery is in the touring and technology package in Canada. At least according to the spec. sheet. Originally only the base model was available unless you purchased in Vancouver, Toronto, or Monteal. I don't think that's the case anymore. The caveat has been removed from the Toyota Canada website.