>18650 batteries (which are the cells typically used in these battery packs)

Absolutely not. Pouch cells are what most powerbanks have.

"Power bank cells are mainly divided into 18650 cells and polymer cells. The most common one on the market is 18650 lithium-ion batteries, with a market share of 70%."

https://www.benzoenergy.com/blog/post/type-of-cells-used-for...

	▲	saidinesh5 3 days ago \| parent [-]
		Looks like the article you've shared is from 2019 (at the bottom of their page?). Things changed a lot since then. Most power banks these days use just lipo pouches.