A fuel cell is an electrochemical device that converts the chemical energy of a fuel, typically hydrogen, into electricity through a chemical reaction with an oxidant, usually oxygen. Unlike a battery, which stores energy and eventually runs down, a fuel cell produces electricity continuously as long as fuel and oxidant are supplied.
How a Fuel Cell Works
A fuel cell consists of two electrodes – an anode (negative electrode) and a cathode (positive electrode) – separated by an electrolyte. The fuel, such as hydrogen, is fed to the anode, where it undergoes oxidation, releasing electrons. These electrons flow through an external circuit, generating electricity. At the cathode, the oxidant (oxygen) reacts with the electrons and hydrogen ions (protons) that have passed through the electrolyte, producing water and heat.
- Continuous Power Generation: Unlike batteries, fuel cells don't need recharging; they produce electricity as long as fuel is supplied.
- Electrochemical Reaction: The process is electrochemical, not combustion, meaning it is cleaner and more efficient.
- Key Components: Anode, cathode, and electrolyte are the essential components.
- Fuel Types: While hydrogen is the most common fuel, others are being explored.
- Byproducts: The primary byproduct is typically water and heat.
Fuel Cells vs. Batteries
The key difference between a fuel cell and a battery lies in their energy storage and usage:
- Batteries: Store chemical energy and release it as electricity until depleted; require recharging.
- Fuel Cells: Continuously convert chemical energy from fuel into electricity as long as fuel is supplied; do not require recharging.
Applications of Fuel Cells
Fuel cells find applications in various sectors, including:
- Transportation: Fuel cell electric vehicles (FCEVs) offer a cleaner alternative to gasoline-powered cars.
- Power Generation: Stationary fuel cells can provide backup power or electricity for buildings and remote areas.
- Portable Power: Smaller fuel cells power electronic devices.
Panasonic Energy Co., Ltd. describes a fuel battery (or fuel cell) as generating electricity "by creating and harnessing energy from a chemical reaction between oxygen and hydrogen (or other fuel types)." This aligns with the Department of Energy's description of fuel cells producing "electricity and heat as long as fuel is supplied."
