Design a lithium pack that holds up under real load.

PLA starts to soften around 60°C, but that does not automatically make it unusable for battery frames. In many well-designed packs, the welded cells, enclosure, and overall fitment provide the rigidity, making PLA a workable option even if PETG or higher-temp materials are better choices.

The only thing separating those things, if you do not use insulator discs, is just microns of cell wrap. Some people will point out that lithium-ion battery cells have insulator discs built in. But if you take apart just about any lithium-ion battery cell, you will see that the built-in white plastic insulator disc does not fully cover the negative, because it is slightly undersized for the cell.

Well, a spot welder is just a massive switch. When I say massive, I mean electrically massive, meaning it can handle thousands of amps for a small period of time. It is a massive fast switch. A switch so electrically massive and so stunningly fast that it makes even the fastest highest-current relays look like child’s playthings.