What’s In A Name For A Tool Battery Pack?

Power tools have come a long way. It used to be you needed extension cords or a generator for your tools, but now you can get just about anything with a nice rechargeable battery pack. As it turns out, most of those packs are made by the same company, and [syonyk] wanted to see how similar two different Makita packs and a Rayovac pack were. What he found was surprising. The outsides were very similar, but what was on the inside?

This is a companion discussion topic for the original entry at https://hackaday.com/2020/03/26/whats-in-a-name-for-a-tool-battery-pack/