What could go wrong?
Not much. All modern solar batteries that I'm aware of (mine included) have built-in fire extinguishing systems. They are required by law. And, before long, lithium ion solar batteries will be a thing of the past. The next battery technology on the horizon is aluminum ion technology. Elon Musk is due to start using them in Teslas in 2026. They are virtually fireproof on their own. This article is little more than clickbait.
Right!?
Stache D has some interesting coverage on car battery fires. He probably addresses the utility scale ones in California.
https://www.youtube.com/@stachedtraining