This is because batteries are, of course, magical devices produced by chemE’s and only begrudgingly handed over to the EE’s, along with instructions like “do not puncture the pouch, or the magic spirits will get free and erupt into a vile flame which burns water.”

I am quite certain they are just doing alchemy and have tricked us all (it is of course well known that chemE’s are actually the cleverest type of engineer).