What is Battery Thermal Management?

The battery is similar to a human being in that it cannot stand too much heat nor does it like too much cold, and its optimum operating temperature is between 10-30°C. And cars work in a very wide range of environments, -20-50°C is common, so what to do? Then equip the battery with an air conditioner to fulfil 3 functions of thermal management:
Heat dissipation: when the temperature is too high, the battery will lose its life (capacity decay) and the risk of violent death (thermal runaway) increases. Therefore, when the temperature is too high, heat dissipation is required.
Heating: When the temperature is too low, the battery will lose its life (capacity decay), weaken (performance decay), and if it is charged at this time, it will also lay the risk of violent death (internal short circuit caused by lithium precipitation has the risk of thermal runaway, which may be the cause of Tesla's spontaneous combustion in Shanghai). Therefore, when the temperature is too low, it needs to be heated (or kept warm).
Temperature consistency: I remember the early air conditioners of the 90s, which started up with a blast of cold air and took a break afterwards. Today's air conditioners, on the other hand, are mostly equipped with inverter and wrap-around blowing functions, in order to keep the temperature consistent in both time and space dimensions. Similarly, power cells need to minimise spatial variability in temperature.