I said "battery assembly" for a reason. Take the real battery, put the charge on the one side, add a layer of packaging to make that entire unit look like a slightly larger battery.
Now it's in the device, but the odds of someone disassembling "the battery" are miniscule. They might remove it and replace it with a legitimate battery during regular use, but they're not going to dissect the tampered one.
If you build the explosive into the battery assembly, no one is disassembling it because no one is going to cut open a lithium cell.
Would it be built into the battery, or into the phone?
I said "battery assembly" for a reason. Take the real battery, put the charge on the one side, add a layer of packaging to make that entire unit look like a slightly larger battery.
Now it's in the device, but the odds of someone disassembling "the battery" are miniscule. They might remove it and replace it with a legitimate battery during regular use, but they're not going to dissect the tampered one.