Lithium-ion Pouch Cell Battery Production Process

Pouch cell lithium-ion battery refers to a battery with aluminum laminated film as the outer packaging.Compared with square aluminum shell batteries and cylindrical batteries, pouch cell batteries generally swell first when there is a safety hazard, or release energy from the place where the seal is broken, which is less likely to explode, so the safety performance is higher;

At the same time, the pouch battery of the same capacity is lighter than the square aluminum shell and has higher energy density. In addition, the shape of the pouch battery can be customized according to customer needs, and the design is more flexible.

The composition of the pouch cell lithium-ion battery is a positive electrode, a negative electrode, and a separator. In addition, the pouch battery also needs electrolyte as a channel for ion transport.

Homogenization: Homogenization refers to the preparation process of the slurry coated on the lithium ion positive and negative electrode sheets. The preparation of the slurry needs to mix the positive and negative electrode materials, the conductive agent and the binder. The prepared slurry needs to be uniform, Stablize.

Coating: The prepared positive and negative electrode slurries need to be coated on Aluminum Foil or copper foil and dried. This process is called coating.

Rolling: The coated pole piece needs to be rolled. Rolling is to pull the pole piece between the rotating rolls through the frictional force between the roller and the pole piece, and the battery pole piece is deformed and densified under pressure.

Slitting and punching: Due to the production capacity and efficiency requirements, the pole rolls in production are relatively large, and the rolled pole rolls need to be cut to the required pole piece size. This process is the process of slitting and punching.

Lamination: The pole pieces after slitting need to be stacked in the order of negative pole, separator, positive pole, separator, negative pole, separator, positive pole... positive pole, separator, negative pole. This process is called lamination, and the pole piece after stacking is called for the battery.

Packaging: The stacked cells also need to be welded by tabs. The welded cells are placed in the aluminum-plastic film after punching, and the top and side sealing processes are performed, that is, packaging.

Liquid injection: Liquid injection is the process of injecting electrolyte into the encapsulated cell. The role of the electrolyte is to provide a carrier for the transport of ions in the battery. Adding specific additives to the electrolyte can improve the performance of lithium-ion batteries in terms of safety or high and low temperature.

Formation: The battery after injection needs to be charged at a small current, which is equivalent to the activation process of a lithium-ion battery. During the first charging process, an SEI film is formed on the surface of the negative electrode. The performance of the SEI film directly determines the rate and self-discharge performance of the lithium-ion battery, so the quality of the formation process directly determines the quality of the battery.