Lithium-iron-phosphate batteries from Thunder-Sky …. as they heat up, they can swell and crack the casing if they’re not squeezed together.

Solid casing for the LFP battery packs needed: Lithium-iron-phosphate batteries from Thunder-Sky. They aren’t as sensitive to temperature, but they do need to be kept under pressure. This bracket is part of a vice I’m building for the batteries. As they heat up, they can swell and crack the casing if they’re not squeezed together. (source)