[stevenrace]

To mitigate issues with cold weather, 2nd generation Nissan Leaf battery packs with the 'cold weather package' include a 'battery warmer' between banks. This is controlled via the BMS which was already monitoring temperature with some thermistors. It's a resistive element like that used in heated seats or an electric blanket.

The Tesla battery is a liquid cooled battery and thus can be warmed via coolant that is heated by the inductive heater for the HVAC. Same for the GM Volt/Bolt.

[Gibbon1]

I was also wondering about two things I've heard they have in northern climes called heated garages and engine block warmers[1]. I assume if one were charging a batter one could also divert some power to keep it warm. Lowered range aside one bonus of an electric car in cold climates is they'll probably start.

[1] As a Californian these things frighten and confuse me.

[kalleboo]

> I assume if one were charging a batter one could also divert some power to keep it warm

The Tesla is always diverting power to keep the batteries warm in the winter. In fact, if you park it outdoors in freezing temperatures, and plug it in to an American single-phase 120V outlet using a long extension cord, all the power will go to keeping the batteries from freezing and it won't charge at all.

[Gibbon1]

Kinda conundrum there, you want good thermal coupling to the environment to shed heat when the batteries are charging. When the car is sitting in the cold you want the batteries insulated.

[stuaxo]

Perhaps bits of metal that can physically touch between the outside and inside (or not) as needed could help ?