Portable electronic products use batteries as power supply With the rapid development of various portable batteries, many new batteries are being used. In addition to conventional high-performance alkaline batteries, rechargeable nickel cadmium batteries and nickel hydrogen batteries, lithium batteries have also been developed in recent years. Here, we introduce the basic knowledge of lithium battery. Including its characteristics, main parameters, model, application range, and paying attention to the use of large capacity lithium batteries
Lithium is a metallic element with the chemical symbol Li (its English name is lithium). It is a silvery white, very soft, and chemically active metal. It is the lightest among metals. In addition to being used in the atomic energy industry, it can also be used to make special alloys, special glasses (fluorescent screen glass used in TV sets) and lithium batteries. It is used as the anode of lithium battery
Lithium batteries are also divided into two categories: non rechargeable and rechargeable. Non rechargeable batteries are called disposable batteries, which can only convert chemical energy into electrical energy at one time, and can not restore electrical energy back to chemical energy (or the reduction performance is very poor). Rechargeable batteries are called secondary batteries (also known as batteries). It can convert electric energy into chemical energy for storage, and then convert chemical energy into electric energy when in use. It is reversible, such as the main characteristics of electric energy chemical energy lithium battery
the cathode materials of lithium-ion batteries are usually composed of active compounds of lithium, while the cathode is carbon with special molecular structure. The main component of the common cathode materials is LiCoO2. During charging, the potential added to the battery poles forces the compounds of the cathode to release lithium ions, which are embedded in the carbon with lamellar structure of the cathode molecules. When discharging, lithium ions are separated from the carbon of the lamellar structure and re combined with the positive compound. The movement of lithium ions produces a current high-capacity lithium battery
although the principle of chemical reaction is very simple, there are many more practical problems to be considered in actual industrial production: the positive material needs additives to maintain the activity of multiple charging and discharging, and the negative material needs to be designed at the molecular structure level to accommodate more lithium ions; In addition to maintaining stability, the electrolyte filled between the positive and negative electrodes also needs to have good conductivity and reduce the internal resistance of the battery
although lithium-ion batteries can rarely remember nickel cadmium batteries, the core of memory effect is crystallization, which is very rare in lithium-ion batteries. However, due to the complexity and diversity, the capacity of lithium-ion batteries will decline after multiple charging. This is mainly due to the change of the positive and negative materials themselves. At the molecular level, the hole structure containing lithium ions on the positive and negative electrodes is gradually destroyed and blocked; From a chemical point of view, it is the passivation of the activity of positive and negative materials, the occurrence of side reactions and the formation of other stable compounds. Physically speaking, positive matter will gradually peel off In short, it will eventually reduce the number of lithium ions that can move freely during battery charging