1. Material to Battery
The production of lithium batteries is a complex and intricate process involving multiple key steps, and is an artistic product from powder materials to complete devices. According to the standardized preparation process of commercial battery cells, the production of materials to battery cells can be roughly divided into the following three processes: electrode preparation (front stage), battery cell assembly (middle stage), and chemical testing (back stage).
Polar film preparation includes: powder drying, batching, homogenization, coating, drying, rolling, cutting
Cell assembly includes: [positive electrode separator negative electrode] lamination/winding, electrode ear welding, bagging/shell insertion, baking, liquid injection, packaging, and coding
Chemical testing includes: chemical formation, vacuum packaging, OCV testing, resistance testing, and capacitance division
According to the shape of the battery cell, it can be divided into button type, cylindrical type, and square type. The application scenarios of different battery cells are slightly different, and button cells are mostly used in remote controls, toys, and other fields. Cylindrical battery cells are commonly used in power banks, toys, 3C digital and other fields. Square batteries are mainly used in high-energy demand scenarios such as 3C digital, power vehicles, and energy storage.
According to the material of the shell, battery cells can be divided into hard shell cells and soft pack cells. Hard shell cells use materials such as aluminum and steel to make the battery shell, while soft pack cells use aluminum-plastic shell stamping to prepare the battery shell. The common 18650 and 4680 battery cells are cylindrical steel shell batteries, while 71274, blade batteries, and short blade batteries are square aluminum shell batteries. As for soft pack battery cells, they are mostly square structures, especially widely used in battery products such as mobile phones.
2. Module&Pack
The whole composed of multiple battery cells connected in series and parallel is called a battery module, and the battery cells are the smallest unit that works independently. A general battery module includes several parts such as battery cells, connectors, plastic frames, casings, cooling plates, protective circuit boards, and BMS. The connectors ensure good series parallel connection of the battery cells, the material frame and shell are used to fix, support and protect the battery cells, the cooling plate is used for battery cooling, and the protection circuit and BMS are responsible for monitoring and managing the battery status, including voltage, current, temperature and other parameters, to ensure that the battery operates in a safe and efficient state.
The combination of multiple modules has become a battery pack. It is not difficult to find that the battery pack is a three-level assembly structure of Cell Module Pack. This connection form has great flexibility. When the battery pack malfunctions, only the damaged battery cells need to be replaced to repair the entire battery pack. In the early days of electric vehicles, most of them were "oil to electricity", which basically unchanged the original electrical structure of the car, changed the engine to an electric motor, and powered by a battery module attached to the bottom of the vehicle chassis. In order to reduce research and development production costs, this method is often used to manufacture power battery packs. However, in order to accommodate larger capacity batteries in limited space, the electrical structure and chassis of current electric vehicles have been redesigned, and this Cell Module Pack structure is rarely used in the electric vehicle field. However, in the fields of outdoor energy storage, industrial and commercial energy storage, emergency power supply, etc., the Cell Module Pack structure is still the mainstream choice due to its high flexibility and ease of maintenance.
3. New era battery pack technology (CTP, CTB, CTC)
The previous text has been improved. In order to fit more batteries into the limited space of the car and improve the overall range, various car companies and battery factories have put a lot of effort into the design of the battery chassis structure. New battery packaging technologies such as CTP, CTB, and CTC have emerged.
ATL represented Cell To Pack
CTP, The full name is Cell to Pack. As the name suggests, integrating the battery cells directly into the battery pack eliminates the intermediate module architecture and simplifies the structure of the entire battery pack. This scheme effectively improves space utilization, reduces the usage of components such as connectors, end plates, and partitions, lowers costs, and increases capacity. In addition, CTP continues the advantages of CTM, as the CTP battery and vehicle body are independent structures, making battery replacement simple and direct.
