edit: after 20 comments, i’m adding a post description here, since most of the commenters so far appear not to be reading the article:
This is about how surprisingly cheap it is (eg $15,000) to buy a complete production line to be able to manufacture batteries with a layer of nearly-undetectable explosives inside of them, which can be triggered by off-the-shelf devices with only their firmware modified.
They don’t necessarily require a starter explosive, certain types do of course. It’s more about overcoming the initial energy required, for example the arc from an electric arc lighter could probably overcome that requirement in a lot of scenarios.
The type of explosive used in this is not a high explosive. If put in a fire it would have exploded