Fumed silica makes new energy vehicles safer and lighter.

Fumed silica makes new energy vehicles safer and lighter

Compared with traditional fossil-fuelled vehicles, the biggest difference of new energy electric vehicles are in the replacement of traditional driving devices such as fuel engines and gearboxes by batteries, motors and energy conversion systems. It has the advantages of zero emissions, High efficiency of kinetic energy conversion (oil and electricity), low noise, etc.

And there is a high demand for thermal management of batteries, chargers and drive motors that generate a lot of heat during normal operation.

When a new energy electric vehicle is running at high speed, the electronic components of the charger and drive motor system will generate a large amount of heat, which will greatly affect the reliability and stability of the parts if temperature control is not performed. At the same time, for the battery system, chemical reactions occur during operation, accompanied by a large amount of heat release, while the battery pack is in a relatively closed environment, which is not conducive to heat dissipation,what’s more, the internal composition of the battery is mostly flammable chemicals, which will cause excessive heat or the battery encounter extrusion vibration. And it will have the potential risk of fire and explosion.

For the thermal management of battery systems, it’s usually used thermally conductive potting adhesives to achieve sealing, thermal conductivity, vibration damping, etc.

Using thermally conductive potting adhesives solutions must be able to meet the following requirements:

Low specific gravity

With the development trend of electric vehicles is lightweight, lower specific gravity can improve the range and efficiency of electric vehicles;

Explosion-proof and flame retardant

The explosion of a single battery cannot cause the explosion and combustion of the whole battery pack, helping to improve the safety performance of the whole vehicle.

High thermal conductivity and superior heat dissipation performance.

The heat emitted from the battery can be conducted out as soon as possible to reduce safety hazards and improve battery life.

Waterproof and anti-vibration

To reduce the damage for the battery from the stress brought by bumps,and to improve the practicality and safety of the whole vehicle.

Thermally conductive potting adhesives for electric vehicles

Potting adhesive materials used for electronic components and power battery modules in electric vehicles can be divided into:

Epoxy resin potting adhesive: single-component epoxy resin potting adhesive, two-component epoxy resin potting adhesive.

Silicone rubber potting adhesive (Silicone potting adhesive): room temperature vulcanization silicone rubber, two-component plus forming silicone rubber potting adhesive, two-component condensation type silicone rubber potting adhesive.

Polyurethane potting adhesive: two-component polyurethane potting adhesive.

The best choice for the current electric vehicle thermal conductivity potting adhesive is silicone potting adhesive has gradually become the best choice for the current electric vehicle thermal conductivity potting adhesive, which has excellent resistance to high and low temperatures, stable physical and chemical properties. It can maintain long-term stable work in the -60 ~ 200 ℃ environment. With the property of soft texture, it has a good damping effect and easy to maintain. With the property of good insulation properties, it has a protective effect on electronic devices.

Silicone potting adhesive used for battery pack encapsulation has excellent flame retardancy, moderate thermal conductivity and low density, which can not only provide waterproof and shock absorption protection for the battery pack, but also help to balance the temperature field, prevent local overheating, and even provide isolation protection to prevent the expansion of the accident in case of local deflagration.

Therefore, using silicone potting adhesive for battery monomer encapsulation has become an important way to improve the safety of lithium battery pack.

Fumed silica property

Fumed silica is made by halosilane in hydrogen and oxygen flame with high temperature hydrolysis condensation , which is a fluffy white ultra-fine powder with a "smoky" appearance, It has a special three-branched structure and high porosity due to its unique preparation process.

Compared with other silica, it has small particle size ( original particle size is between 7-40nm), large specific surface area (100-400m2/g), high surface activity (The surface contains highly reactive Si-OH groups), good dispersion, strong surface adsorption, with excellent reinforcement, high and low temperature resistance, thickening thixotropic, anti-settlement, insulation, stability and other characteristics.

Fumed silica as a functional filler in the application of silicone potting adhesive plays a huge role. It can ensure that has excellent thermal conductivity in new energy vehicles and a large number of applications, not only significantly improving the safety of electric vehicles, but also more beneficial to the realization of light weight.

According to figures, the weight of the battery module in a new energy vehicle of a family car is about 150~400kg, the use of silicone thermally conductive potting adhesive is about 20~50kg. Under the same volume filling, the specific gravity of the adhesive is to reduced and the performance of the potting adhesive is enhanced, then it can reduce the weight of the electric vehicle to a certain extent. And it promotes the development of new energy vehicles.


Post time: Nov-18-2021