Lightbulbs are measured in watt. Batteries are measured in volt.
A watt is a unit of electrical power, which expresses how much energy gets used or transmitted per second. A volt is a measure of electric potential, which expresses how much energy you get per unit charge.
The relationship of watt and volt is tied to ampere with the formula:
watt = ampere * volt
Whether a lightbulb or battery has more power depends on the size of the lightbulb and the size and type of battery.