button battery cr2032.What is fuel cell technology_Advantages and disadvantages of fuel cell technology

　　A fuel cell is a chemical device that directly converts the chemical energy of fuel into electrical energy, also known as an electrochemical generator. It is the fourth power generation technology after hydropower, thermal power and atomic power. Because the fuel cell converts the Gibbs free energy part of the chemical energy of the fuel into electrical energy through electrochemical reactions, it is not limited by the Carnot cycle effect, so it is highly efficient; in addition, the fuel cell uses fuel and oxygen as fuel without mechanical Transmission components, so there is no noisy material, and very few harmful gases are emitted; sound pollution. It can be seen that from the perspective of energy conservation and ecological environment protection, fuel cells are the most promising power generation technology.

　　Fuel cell principle

　　The principle of a fuel cell is an electrochemical device, and its composition is the same as that of a general battery. Its single cell is composed of two positive and negative electrodes (the negative electrode is the fuel electrode and the positive electrode is the oxidant electrode) and an electrolyte. The difference is that the active materials of general batteries are stored inside the battery, therefore, the battery capacity is limited. The positive and negative electrodes of the fuel cell do not themselves contain active substances, but are just catalytic conversion elements. Therefore, the fuel cell is truly an energy conversion machine that converts chemical energy into electrical energy. When the battery is working, fuel and oxidant are supplied from the outside and react. In principle, as long as the reactants are continuously input and the reaction products are continuously eliminated, the fuel cell can continuously generate electricity.

　　Fuel cell structure

　　The main components of a fuel cell are: electrode (Electrode), electrolyte membrane (ElectrolyteMembrane) and current collector (CurrentCollector), etc.

　　1. Electrode

　　The electrode of the fuel cell is the electrochemical reaction site where the oxidation reaction of the fuel occurs and the reduction reaction of the oxidant occurs. The key to its performance lies in the performance of the catalyst, the material of the electrode, and the manufacturing process of the electrode.

　　The electrode can be mainly divided into two parts, one is the anode (Anode) and the other is the cathode (Cathode). The thickness is generally 200-500mm; its structure is different from the flat electrode of the general battery in that the electrode of the fuel cell is porous. structure, so the main reason for designing a porous structure is that most of the fuels and oxidants used in fuel cells are gases (such as oxygen, hydrogen, etc.), and the solubility of gases in the electrolyte is not high. In order to increase the actual operating current density of the fuel cell In order to reduce polarization, electrodes with porous structures were developed to increase the electrode surface area participating in the reaction. This is also one of the key reasons why fuel cells can move from the theoretical research stage to the practical stage.

　　At present, the electrodes of high-temperature fuel cells are mainly made of catalyst materials, such as Y2O3-stabilized-ZrO2 (YSZ) of solid oxide fuel cells (SOFC) and nickel oxide electrodes of molten carbonate fuel cells (MCFC). , and low-temperature fuel cells are mainly composed of a gas diffusion layer supporting a thin layer of catalyst material, such as the platinum electrodes of phosphoric acid fuel cells (referred to as pAFC) and proton exchange membrane fuel cells (referred to as pEMFC).

　　2. Electrolyte separator

　　The main function of the electrolyte separator is to separate the oxidant and the reducing agent and conduct ions. Therefore, the thinner the electrolyte separator, the better. However, the strength must also be taken into consideration. As far as the current technology is concerned, its general thickness is about tens to hundreds of millimeters. ; As for materials, there are currently two main development directions. One is to first make a porous separator from insulating materials such as asbestos (Asbestos) film, silicon carbide SiC film, lithium aluminate (LiAlO3) film, and then immerse it in molten lithium-potassium carbon. Acid, potassium hydroxide, phosphoric acid, etc. are used to adhere to the membrane pores. The other is to use perfluorosulfonic acid resin (such as pEMFC) and YSZ (such as SOFC).

　　3. Current collector

　　The current collector, also known as a bipolar plate, has the functions of collecting current, separating oxidants and reducing agents, and channeling reaction gases. The performance of the current collector mainly depends on its material properties, flow field design and processing technology.

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