Lithium ion batteries in devices are sandwiched layers enclosed in a kind of 'pouch', right? So what if you manufactured one of these that looked identical to t

Lithium ion batteries in devices are sandwiched layers enclosed in a kind of 'pouch', right? So what if you manufactured one of these that looked identical to the normal battery, but only had half a battery inside, and the rest of it was plastic explosive. Maybe put a tiny chip in there that, when a particular pattern of current draw happens, fires a detonator. Then, some firmware hack in the device proper that responds to some event and actuates that current draw pattern. It wouldn't even look suspicious if you opened it up.