From a certain temperature, cells start to self-heat, e. g. at the rate of 0.02 °C/min. The onset temperature can be 100 °C for new cells but only 30 °C for cycled cells [1].
However, this assumes the cell cannot dissipate heat. An active cooling system in a battery can more than compensate for the self-heating of cells.
Lithium plating is responsible for the lower onset temperature because Lithium reacts with the electrolyte exothermically. Especially Lithium deposited in dendrites because they have large surface area [2]. Furthermore, Lithium plating increases the self-heat rate [1].
Part of Battery safety.
[1] Interaction of cyclic ageing at high-rate and low temperatures and safety in lithium-ion batteries (2015)
[2] Li plating as unwanted side reaction in commercial Li-ion cells – A review (2018)