Lets start with the cells.

BYD prismatic cells seem to be the preferred ones. They advertise -

The cell has a larger surface area than regular prismatic cells, allowing for better heat dissipation. The cells also allow for slow heat release, lower heat generation, high starting temperature for exothermic reactions, and do not release oxygen during thermal runaway.


It looks like I will be spending the next few weeks doing research into lithium batteries.