Please briefly describe the working principle of fuel cell.

The working principle of fuel cell is to directly convert the chemical energy of fuel and oxidant into electrical energy through electrochemical reaction.

Fuel cell is a chemical device that directly converts the chemical energy of fuel into electrical energy, also known as electrochemical generator. It is the fourth power generation technology after hydropower generation, thermal power generation and atomic power generation.

Because the fuel cell partially converts Gibbs free energy in fuel chemical energy into electric energy through electrochemical reaction, it is not limited by Carnot cycle effect, so it has high efficiency. In addition, the fuel cell uses fuel and oxygen as raw materials, and has no mechanical transmission parts, so it has less harmful gas emission and long service life. Therefore, from the point of view of energy saving and ecological environment protection, fuel cell is the most promising power generation technology.

Basic introduction

Fuel cell is a kind of power generation device that directly converts the chemical energy of fuel and oxidant into electrical energy through electrochemical reaction. Theoretically, the fuel cell can operate at a thermal efficiency close to 100%, which is very economical. At present, due to the limitation of various technical factors, considering the energy consumption of the whole plant system, the total conversion efficiency is mostly in the range of 45% ~ 60%, and it can reach more than 80% if the heat removal utilization is considered.

In addition, the fuel cell device contains no or few moving parts, which is reliable, requires less maintenance, and is quieter than the traditional generator set. In addition, chemical energy is directly converted into electrical energy by electrochemical method at isothermal temperature without going through the thermal engine process and being limited by Carnot cycle. The energy conversion efficiency is high, the reaction is clean and complete, and less harmful substances are produced. It is becoming an ideal energy utilization mode.

At the same time, with the continuous maturity of fuel cell technology and the abundant natural gas source provided by the West-to-East Gas Transmission Project, fuel cell is regarded as a promising energy power device, and its commercial application has broad development prospects.

Principle and composition structure

Fuel cell is an energy conversion device, and its composition is the same as that of ordinary battery. It directly converts the chemical energy stored in fuel and oxidant into electric energy according to the electrochemical principle, that is, the working principle of primary battery, so the actual process is redox reaction. Taking hydrogen-oxygen fuel cell as an example, the reaction principle of fuel cell and hydrogen-oxygen fuel cell is explained. This reaction is the reverse process of electrolyzing water. Electrodes shall be:

Negative electrode: H2+2OH -→ 2H2O+2E-; Positive electrode:1/2o2+H2O+2e-→ 2oh-; Battery reaction: H2+ 1/2O2==H2O.

Fuel cell is mainly composed of three parts, namely, electrode, electrolyte membrane and external circuit (current collector).