Battery Pack Seals

Chemical resistance: The electrolyte in the battery pack is corrosive, and the seals must withstand the electrolyte. For example, in lithium-ion battery packs, the electrolyte is mainly a mixed solution of organic carbonate solvents and lithium salts, and the sealing material should be able to contact it for a long time without chemical reaction, dissolution, or expansion, etc., to ensure the long-term stability of sealing performance.

Temperature resistance: The battery generates heat during charging and discharging, increasing the internal temperature of the battery pack. Seals must maintain good elasticity and sealing properties over a wide temperature range. In general, it is necessary to accommodate a wide temperature range of -40°C to 80°C or even more. It will not become brittle and crack in a low-temperature environment. It will not soften and deform in a high-temperature environment so the battery pack is always effectively sealed.

Good elasticity and compression recovery: The seals are subjected to some degree of compression during installation to fill the gaps between the battery pack housings. It needs to have good elasticity to provide sufficient sealing force after compression. In addition, when exposed to changes in external pressure or slight deformation of the battery housing, the seal must quickly return to its original state and maintain the sealing effect.

Ethylene propylene diene monomer (EPDM): This rubber has excellent weather resistance, chemical resistance, and good elasticity. It is resistant to many chemicals, including battery electrolytes, and is stable at different temperatures, making it one of the most commonly used materials for battery pack seals. For example, in some outdoor energy storage battery packs, EPDM seals are effective against UV rays, rain, and chemicals inside the battery.

Fluoroelastomer (FKM): Fluoroelastomer has excellent chemical resistance and high temperature resistance. It can withstand more corrosive electrolytes and higher operating temperatures, making it suitable for high-performance battery packs. For example, in some high-energy-density power battery packs, the operating temperature may be higher, and FKM seals can better ensure the sealing and safety of the battery pack.

Flat Seal Construction: This is the most common one, and the seal is usually a flat rubber gasket placed between the bonding planes of the battery pack housing. When the shell is tightened by bolting, etc., the seal is compressed, resulting in a seal. This structure is simple and effective and is suitable for the sealing of the housing of most battery packs.

Trough sealing structure: A sealing groove is designed at the edge of the battery pack shell, and the seal is embedded in the groove. This structure allows for better retention of the seal and prevents it from shifting during assembly. In addition, the sealing groove can play a certain role in protecting the seal and improving the reliability of the seal. This construction may be used in some battery packs that require extreme sealing requirements, such as those used in the aerospace sector.