Identifying this battery configuration

[janpom]

This thread has the context:

Firesafe board storage container

My board caught on fire today. It came out of nowhere. I just pulled the board as a trolley for a bit and when I laid it down, it started hissing and burning. Something inside the battery pack must have shorted out. I assume some mechanical damage caused by carrying the board in the vertical position. Anyway, I’m glad it didn’t happen in my apartment. It easily could have since I always carry my board home in the same way. I feel like I have severely underestimated the safety measures wrt stor…

TL;DR: I don’t know. It’s a bit of a mystery.