>>51092576Part of the point of the battery is to smooth out the power.
Think of power flow as water.
You need to get a steady constant flow of water, but the incoming is instead, gushing and trickling some.
So you put a reservoir (the battery) in the flow.
The reservoir can have a nozzle in the bottom and will output a constant stead flow. The input will fill the reservoir, so regardless of any spikes in flow in, you see a nice smooth continuous flow.