Hi Roshee! Thank you for playing the game :)
The Battery stores energy when touched or jumped on. When full, the energy is released to the next Roboto that bounces on it, adding a multiplier to the scrap metal collected. It's cumulative for some robots. ;)
Try a settup with these four blocks on a line : Start-Battery-Basic-End, and you'll see what happens everytime the block is full, and what happens when the arrow is down.