The basic structure and principle of lithium battery

1. Overview of lithium battery (1) Basic structure and principle of lithium battery Lithium battery is a rechargeable battery, which mainly relies on lithium ions to move between the positive and negative electrodes. During the charging and discharging process, Li+ intercalates and deintercalates back and forth between the two electrodes. In rechargeable batteries, lithium ions are extracted from the positive electrode and inserted into the negative electrode through the electrolyte. When unloading, the situation is just the opposite. Lithium batteries are generally composed of five parts: positive data, negative data, gap, electrolyte, battery case, etc. The structure diagram of the circular lithium battery is as follows: (2) The basic shape of the lithium battery Lithium batteries are divided into two categories according to the packaging shape: metal casing packaging and flexible packaging. In addition to different shell data, packaging methods are also different. The soft core uses aluminum-plastic packaging film as the packaging information, and the hot packaging method is preferred, while the metal shell core generally uses a steel shell or an aluminum shell, and chooses the packaging method of welding (laser welding). The principle diagram of the aluminum-plastic packaging film is as follows: The metal casing mainly includes two kinds of round lithium batteries and square lithium batteries. According to the specific types, round lithium batteries can be divided into 18650 and 21700. 18650 batteries: 18650 is the originator of lithium batteries, a standardized lithium battery model launched by Sony Japan in order to save costs, where 18 represents a diameter of 18mm and 65 represents a length of 65mm ,0 means cylindrical battery. 21700 battery: jointly developed by Tesla and Panasonic, 21 means diameter 21mm, 70 means length 70mm, and 0 means cylindrical battery. (3) The cost composition of lithium batteries At present, the cost of lithium battery companies is about 1.2 yuan/Wh. Automobile power lithium-ion battery capital structure, information capital ratio is close to 75%, human capital, capital (except for human capital, which is directly related to battery processing, such as workshops, equipment, electricity, etc.), and other capital (importantly including capital capital Fund usage, environmental protection, etc.), accounting for about 25% of the total. The capital structure of lithium batteries is shown in the following figure: In the lithium battery data cost structure, the positive electrode data accounts for about 43% of the cost, and the function and price of the positive electrode data are directly determined The function and price of lithium batteries. From the data point of view, a 1kWh power lithium-ion battery needs to use about 2.3~2.5kg of positive data. The cost of the positive data is mainly composed of lithium carbonate and various corresponding precursor data; a 1kWh battery requires about 1.3~1.4kg of negative data. . The amount of electrolyte varies greatly depending on the data of the positive electrode used. Among the 1kWh power lithium-ion batteries, there are 1.2kg (such as the lithium manganate battery used in Leaf), 1.6kg (such as the lithium manganate + NCM triple battery used in Volt), and 2.16kg (such as the iron phosphate used in PHEV) lithium battery). The amount of gap data of different power lithium-ion battery products is also very different. Take a representative company as an example. Among the 1kWh power lithium-ion batteries, AESC’s lithium manganese battery uses a gap of about 12.5 square meters, while LG Chem’s lithium manganate + ternary battery is close to 19 square meters, while BYD’s phosphoric acid The iron-lithium battery needs 23.5 square meters. 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 article: Why do pure electric vehicle batteries need to be warmed up?