Knowledge analysis: the working principle of lithium batteries

Knowledge analysis: analysis of the working principle of lithium batteries In our daily life, lithium batteries are often considered right and wrong. For example, we use mobile phones, laptops, tablets and other devices to rely on it to operate, but you know it Does it work? If you don’t understand, hurry up and follow the author to learn about the working principle of lithium batteries. 1. The working principle of lithium battery. Brief analysis Lithium battery is a kind of secondary battery, which consists of two kinds of reversible intercalation and non-intercalation lithium ion compounds as positive and negative electrodes. When the battery is charged, the lithium atoms of the positive electrode ionize into lithium ions and electrons, and the lithium ions move to the positive electrode to form lithium atoms with the electrons. During the discharge process, lithium atoms ionize from the anode surface of the graphite crystal into lithium ions and electrons, forming lithium atoms at the cathode. Therefore, lithium is usually in the form of lithium ion, not metal lithium, so this is called a lithium battery. 2. Working principle-structure of lithium battery Lithium battery is a replacement product for lithium battery that appeared a few years ago. The battery is mainly composed of positive electrode and negative electrode, electrolyte, separator and shell. Positive electrode-Choose a carbon electrode that can absorb and store lithium ions. When lithium is discharged, lithium becomes lithium ions, leaving the positive electrode of the battery and reaching the negative electrode of the lithium battery. The choice of the negative electrode material is as close as possible to the potential of lithium, which can be inserted into lithium compounds, such as various carbon materials, including natural graphite, composition graphite, carbon fiber, central phase carbon and metal oxides. Electrolyte-a mixed solvent system composed of LiPF6 ethylene carbonate, propylene carbonate, low-viscosity diethyl carbonate and other alkyl carbonates. The membrane is made of polyethylene microporous membrane, such as PE, PP or its composite membrane, especially PP/PE/PP three-layer membrane, which not only has a low melting point, but also has high wear resistance, which can be used for thermal safety. The shell is made of steel or aluminum, and the shell assembly has an explosion-proof power-off function. 3. The working principle of lithium battery The working principle of lithium battery is the principle of charge and discharge. When the battery is charged, lithium ions are formed at the positive electrode of the battery, and the lithium ions reach the negative electrode through the electrolyte. Carbon, that is, the negative electrode, has a layered structure with many micropores, and the lithium ions reaching the negative electrode are embedded in the micropores of the carbon layer. The more lithium ions are inserted, the greater the charging capacity. The chemical reaction at the positive electrode at this time is the same: when the battery is discharged (the process we use the battery), the lithium ions embedded in the negative electrode carbon will come out and return to the positive electrode. The more lithium ions return to the positive electrode, the greater the discharge capacity. When we talk about battery capacity, we are referring to discharge capacity. The chemical reaction that occurs on the negative electrode at this time is: It is not difficult to see that during the charging and discharging process of a lithium battery, lithium ions move from the positive electrode to the negative electrode, and then to the positive electrode. Let us think of the lithium battery as a rocking chair. The two ends of the rocking chair are the north and south poles of the battery. Lithium ion, like an excellent athlete, moves back and forth on both ends of the rocking chair. Therefore, the experts gave the lithium battery their favorite name: rocking chair battery. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: Solutions to the bottleneck of lithium battery applications