At some point, the 3.6 V of a single lithium ion battery just won’t do, and you’ll absolutely want to stack LiIon cells in series. When you need high power, you’ve either got to increase voltage or current, and currents above say 10 A require significantly beefed up components. This is how you’re able to charge your laptop from your USB-C powerbank, for instance.
This is a companion discussion topic for the original entry at https://hackaday.com/2024/04/04/ultimate-power-lithium-ion-batteries-in-series/