Introduction of silicone foam
Silica gel foam material (also known as silica gel foam / foamed silica gel) is a kind of porous, low density and compressible polymer elastomer, which is made from raw rubber, filler, vulcanization accelerator, foam rubber and other raw materials, mixed evenly, and then made by special process under high pressure and high temperature. Because of the high elasticity of silicone rubber and the sound insulation and shockproof properties of foam materials, it is widely used in life, and is widely used as damping pad, sealing gasket, sound absorbing material, insulating material and aeronautical thermal insulation material. According to the cell structure, silicone foam can be divided into three types: closed cell, open cell and mixed cell.

Closed cell foam silicone foam material has better shockproof cushioning, sound insulation, heat insulation and flame retardant and explosion-proof characteristics. It is mainly used in automotive field for automotive air-conditioned insulation foam tube, automobile shock absorption, new energy vehicle battery foam silicone gasket. Nowadays, many automotive interior materials, such as floor, ceiling, steering wheel and car seat, are polyurethane foam materials. On the one hand, the technology of polyurethane foam materials is relatively mature, and the performance meets the use standards; on the other hand, the price of polyurethane foam materials is low. However, polyurethane foam has poor weatherability and flammability and releases a lot of toxic gases harmful to human body during combustion. Therefore, with the promotion of organic silicone foam materials and the improvement of people's understanding, organic silicone foam materials are expected to replace traditional polyurethane foam materials in the future.

Characteristics of silicone foam

Density of silicone foam　

The density of silicone foam is 1.17g/cm3. However, through foaming treatment, the density of the organosilicon foam material prepared in the current mature process can be 0.16-0.20 g/cm3, which can be used for car seat and headrest. The conventional silicone rubber foam material (density of 0.45 g/cm3) is widely used for gap filling in sealing and shock reducing parts.

Flame retardant properties of silica gel foam

According to the scientific experimental data, the silica gel foam with flame retardant has good flame retardant performance, and the flame retardant grade can reach ul94-v0. It can be used in electric vehicles, which can reduce the problems caused by combustion.

Electrical insulation properties of silicone foam

With the increase of the amount of physical filler, the volume resistivity and surface resistivity of silicone rubber decreased, while the dielectric constant and dielectric loss factor increased. It can be seen that the electrical insulation properties of silicone rubber are damaged to a certain extent by adding physical fillers.

Application of silicone foam in electric vehicle industry

Battery cell is the source of kinetic energy of pure electric vehicle. The potential safety hazard of battery cell seriously endangers the safety of the whole vehicle. When the battery cell is working, it will produce a certain amount of heat. At different temperatures, it can produce a certain effect of thermal expansion and cold contraction, resulting in a certain expansion of the battery cell. The long-term capacitive grid friction between the battery cells is likely to cause the damage of the battery cell, resulting in invalid rechargeable battery, or even even worse beyond control. In addition, when the output voltage of the battery pack reaches above 200V, it is stipulated that the shell of the rechargeable battery must be sealed and waterproof to avoid short circuit caused by water seepage. The waterproof grade of the shell of the rechargeable battery is IP67.

Silica gel foam has the characteristics of high reduction, which can avoid the deformation caused by the thermal expansion and cold contraction of the rechargeable battery cell during the whole process of battery charging and discharging. It has excellent durability, low reduction, impact digestion and absorption and flame retardancy (UL 94 V0 grade). At the same time, silica gel also has good waterproof performance, as well as the following properties, so it is widely used in the cache, thermal insulation and frame sealing of new energy cell.

1. At different temperatures, silica gel foam performance is stable, commodity sealing ring performance is stable. 2. Excellent waterproof sealing, no water seepage when the commodity goes out for use. 3. Long term shrinkage damage is small, has a certain ability to contain shrinkage deformation. 4. Excellent flame retardant performance, can effectively prevent the risk of battery work due to thermal effect. 5. Thickness and strength can be adjusted according to different standards Quasi design, the sealing ring must be well matched with the housing and the internal stress is low, which can effectively avoid the bending of the sealing ring and arching the silicone foam gasket. The application of silicone foam gasket in the sealing of new energy lithium battery frame.