Foam can provide excellent heat insulation, cushioning, flame retardancy, sealing, support, shock absorption and other functions in the power battery pack, so foam can be used in different areas of the battery pack.

Between the battery cells, when the cells are expanded and contracted, the foam can play a role in heat insulation buffer; When the cell is thermally runaway, the foam can prevent the heat transfer and has flame retardant performance; In the battery pack, located under the liquid cold plate or next to the upper and lower box covers, the foam can play a supporting and shock absorption role; It can also be used as a battery seal.

There are many types of foam, including PU, EVA, PE, CR, ECR, silicone foam and so on. In the actual application process of the battery system, the foam suitable for the cells is generally PE, PU and other materials; The foam that plays a role in support, shock absorption and other functions in the battery box is generally EVA, PE, ECR, EVA+CR, silicone foam and other materials. The foam used as a battery seal is generally a material such as silicone foam.
Application of foam between power battery cells

The battery cell is the source of energy for electric vehicles, the safety of the battery directly affects the safety of the whole vehicle, the battery cell will produce a certain amount of heat when working, a certain thermal expansion and contraction will occur at different temperatures, the cell will swell to a certain extent, and the long-term contact friction between the cells may lead to cell damage causing battery failure or even loss of control.

The performance requirements of new energy power batteries for inter-cell foam products are as follows:
1. Low hardness and high rebound, which can absorb the stress caused by thermal expansion and contraction and play a buffering role;
2. Low thermal conductivity, when thermal runaway occurs, it can insulate heat, inhibit heat diffusion and delay the occurrence of accidents;
3. Flame retardant performance, when the battery cell fires, the flame retardant effect can delay the spread of the fire;
4. Excellent resilience, wide proportion of compressibility, as positioning;
5. Small thickness, less space occupation, long life.

Application of foam in battery box support
Thermal management plays a pivotal role in the power battery, directly related to the safety of the battery pack and the whole vehicle, the cooling system inside the battery pack has been converted from traditional air cooling to liquid cooling device, the battery pack and the liquid cold plate through thermal conductive silicone to conduct heat, but due to the poor elasticity of thermal conductive silicone, long-term use has thickness loss, resulting in insufficient contact between the liquid cold plate and the battery pack, affecting the thermal conduction effect.

The solution can be set under the liquid cold plate spring or foam as a support material to ensure good contact between the liquid cold plate, thermal conductive silicone, and module.

The performance requirements of the battery box support foam are as follows:
1. Stable support and good shock absorption effect;
2. Excellent temperature resistance and durability;
3. Small compression set and stress relaxation loss;
4. It has excellent flame retardant performance to ensure the safety of combustion.

Application of foam in power battery seals
Battery pack is the core energy source of new energy vehicles, providing driving power for the whole vehicle, in order to protect the internal components of the battery pack from dust, rain and other erosion, the shell seal of the battery pack must reach a certain dustproof and waterproof level. At present, the industry requires battery packs to be protected against dust and water, and the protection level generally reaches IP67 or IP68. There are three main categories of battery pack shell sealing materials on the market: rubber sealing rings, sealants and foam, of which foam materials generally use silicone foam.

Silicone foam material has excellent resistance to compression set, creep resistance can resist material collapse caused by compressive stress and temperature changes after long-term use, and extend the life of the battery by continuous sealing and shock absorption.

For silicone foam, please check the details:
https://www.siliconefoam.net/product-medium-firm-silicone-foam-iota-ht-800-.html