>>1371673300W motor is less powerful than human, which can provide 250W in long term, and 1,5+kW in burst, while 250W can only output 500W in short bursts.
Batteries, on the other hand, are dangerous. They contain fuck ton of energy in them, and poorly designed pack will catch fire in case of failure. Hell, even good designed battery packs, like in Tesla can catch on fire.
From my experience, low current batteries (i.e. ones that are used in laptops and such) are really safe, since chemistry doesn't allow them to output their entire stored energy in short period of time (short circuit current is no more than 20A, and will drop quick with heat), and you can safely poke them through with nail, it will just vent some smoke and heat maybe to 150 C.
Batteries used in EVs are much more powerful, they store same amount of energy, but they can release it quickly (20A continuous) , and they tend to increase output current with temperature, which means they will get cherry hot if you poke them, or maybe even explode.
In order to be safe, you must reduce charging voltage to 4.1 (90-ish % charge) or lower, since for some reason, at full charge it tends to explode if punctured.