taraf The battery pack does perform best within a certain temperature range and does have a temperature management system for that purpose, but you can overcome a lot of its limitations by conditioning the battery before departure - something you can do while it’s plugged into a wall.
This can’t be overstated - temperature is absolutely key with Lithium battery chemistries, and in a weird way, they have some bizzare quirks that makes them, ornerous, while useful.
Lithium Ion (and LiFePO4) batteries can not and should not be charged when their internals are below 0C. They can form ice crystals and cause internal punctures in the membranes severely degrading if not destroying them. All automotive Lithium batteries, in Hybrids, PHEV, and EV vehicles have some sort of heating system to deal with this. In normal hybrid cars the battery will only charge when engine coolant or electricity from the hybrid drive train has managed to heat the cells above 0C. In PHEV’s, when you plug in to charge the cells will be heated by the wall energy before they begin to charge (this is why its best to plug the car in to charge immediately after driving if possible, as the cells will already be up to temperature). In EVs - the batteries can heat themselves “pre conditioning” if necessary before being ready to take a charge.
Next up - Lithium Ion and LiFePO4 cells should not be discharged below -4F/-20C , this too can damage the cells and shorten their life. If you live somewhere very cold don’t leave your cordless electric snowblower batteries out in the shed at -30C and expect it to work in the morning. Most Hybrid and PHEV vehicles will disable the electric drivetrain below -20C until the cells have warmed up either with engine waste heat, electricity from the hybrid drive system, or if you’ve had it plugged in charging it will be maintaining a usable temperature in preparation for your driving. Pure EVs need to use their internal battery heating systems, which diminishes range pretty significantly, to keep the batteries at a good usable temperature. Generally battery capacity itself is diminished by about 10% at temperatures between 0 and -20C, add in the need to heat the cells, and you’re easily down 25%.
Now whats really weird is the cells themselves perform extremely well in “high” temperatures - what you and I would think of as “hot” but isn’t really “hot” for the cells - that is 30 to 45C is a sweet spot for Lithium chemistry batteries, they can charge and discharge rapidly when at those temperatures with little to no ill effects. They love being “warm”. The problem is they ABHOR getting hotter than 60C - the best way to shorten the life of any LiIon battery - your cell phone, cordless tools, EV, PHEV, etc - every minute they spend over 60C is something like 4 hours off their life – 1 hour at 60C is like 250 hours of normal operation. Don’t leave your cell phone in the sun in the car on a hot day. But you can see the “problem” here - the cells love being between 30-45C, and work really well there, but as soon as they are over 60C (and especially closer to 70C) they tear themselves apart inside (especially LiIon, LiFePO4 are a little more tolerant to heat but are still sensitive to very high temps). This means there’s very little room to play around with if your cells are running in their “sweet spot” around 45C, it doesn’t take much high ampere draw or charge rate to drive them up around 60-65, and that’s bad. This is why most EVs have pretty stout battery cooling systems on top of their battery heating systems - they’ve got to walk that line to get the best performance but avoid damage.
