A fuel cell is a chemical device that directly converts the chemical energy of the fuel into electrical energy, also known as an electrochemical generator.
It is based on the electrochemical principle, that is, the working principle of the galvanic cell, isothermally converting the chemical energy stored in the fuel and oxidant into electrical energy, so the actual process is an oxidation-reduction reaction.
The fuel cell is mainly composed of three parts, the electrode, the electrolyte and the external circuit.
The fuel cell electrode is the electrochemical reaction site where the fuel undergoes oxidation reaction and the oxidant undergoes reduction reaction. It mainly includes an anode and a cathode. The thickness is generally 200-500mm. Its structure is different from ordinary battery flat electrodes. It is a porous structure. The purpose is to improve fuel The actual operating current density of the battery.
The electrolyte plays the role of transferring ions and separating fuel gas and oxidizing gas. In order to prevent the mixing of two gases from causing a short circuit in the battery, the electrolyte is usually a dense structure.
The external circuit is generally composed of bipolar plates. The bipolar plates have the functions of collecting current, separating oxidants and reducing agents, and channeling reaction gases. Its performance mainly depends on its material characteristics, flow field design and processing technology.
Commonly used fuel cells can be divided into proton exchange membrane fuel cells (PEMFC), solid oxide fuel cells (SOFC), molten carbonate fuel cells (MCFC), phosphoric acid fuel cells (PAFC) and alkaline fuels according to their different electrolytes. Battery (AFC).
Proton exchange membrane fuel cell (PEMFC) is currently a relatively mature and widely used fuel cell due to its multiple performance advantages, including low battery operating temperature and fast start-up speed. It accounts for global shipments and megawatts of shipments. leading position.
The fuel of the fuel cell is mainly hydrogen, methanol and other hydrocarbons. The fuel cell in this article mainly takes hydrogen fuel cell as an example for analysis.