For those interested in how a high-end lithium polymer pack is constructed, I ran across this video disassembly of a Kong Power Lithium Polymer battery pack.
Yeah, I know, not really interesting to a lot of us, but the useful thing is that it dispels rumors about the pack that it had cardboard to disguise puffing batteries, among other issues. I prefer packs that use PCBs rather than just soldering the poles together, as it’s easier to repair or modify the pack if necessary. I also think that I prefer packs with spacers inside, because the few batteries I’ve run to over 300 cycles all had spacers, while among those which didn’t last as long, none did.