Energy Storage and Energy Conversion devices are both used to fill the need for portable as well as renewable power. Specific technologies are batteries, capacitors, fuel cells and solar cells. In commercial devices, these are often used in combination as part of a power system.
The evolving need requires the improvement in capability to provide pulse-power, long run-time and cycle life. Often power sources also have engineering constraints of volume and weight. New materials and advancements of engineering play a key role in meeting the market demand. The power available from a device is defined by the product of its voltage and current. The voltage of a single device is defined by its specific chemistry. The current of a single device is defined by its size (electrode area).