China International Battery Fair 2021:
WACKER Presents Silicone Solutions for EV Battery Modules
Shenzhen, Mar 19, 2021
At the China International Battery Fair (CIBF) 2021, WACKER will present a range of silicone solutions for battery modules of electric vehicles. Of these, the SEMICOSIL® 96XX TC low-density thermally conductive gap filler series is not only conducive to the trend toward lightweight battery modules, but also helps to reduce costs and allows automatic production. The ELASTOSIL® RT 7XX TC series of low-viscosity thermally conductive potting compounds features excellent flow properties and can readily penetrate into small gaps. It is the ideal potting material for the protection of power components in onboard chargers. Silicone foam ELASTOSIL® SC 8XX series provides a reworkable cured-in-place gasket (CIPG) solution for battery module sealing and allows automatic production. CIBF 2021 takes place in Shenzhen, China, from March 19 to 21.
Battery modules usually account for more than 20% of the total weight of the electric vehicle while, in terms of cost, the ratio is even higher, at 30%-60%. WACKER’s low-density thermally conductive gap filler SEMICOSIL® 96XX TC series conforms to the lightweight trend and helps to reduce material costs for battery and vehicle manufacturers. It is especially suitable for thermally conductive gap filling in key components such as the batteries and electric control units of electric vehicles.
SEMICOSIL® 9620 EV TC, for example, has a thermal conductivity of 2.0 W/m·K and a cured density of 1.9g/cm3. Compared with most traditional products with the same thermal conductivity, its density is more than 25% lower, which means it is lighter for the same volume usage or can achieve higher thermal conductivity for the same weight usage.
Compared with traditional thermal pads or thermally conductive gap fillers, SEMICOSIL® 9620 EV TC has a better aging-resistant performance. After a variety of severe long-term aging tests (such as high temperature and high humidity, thermal shock and a temperature of 145°C for 2000 hours), all key properties of the product remain stable. This means it has a longer service life. As a soft thermally conductive gap filler with good adhesion and elasticity, after curing, SEMICOSIL® 9620 EV TC can effectively adhere to the interface between the component and the cold-water board, or to other heat dissipating interfaces, thus ensuring good vibration resistance. The use of a dispensing process, instead of conventional manual gasket fitting after cutting, means that the product flows under pressure before curing and can fill the gap completely. Thus, the product can significantly improve heat transfer and results in reduced assembly stress.
Other WACKER product highlights at 2021 CIBF include:
ELASTOSIL® RT 7XX TC Series
The ELASTOSIL® RT 7XX TC series of low-viscosity thermally conductive potting compounds includes several products with different thermal conductivities (ranging from 1.2W/m.K to 2.0W/m.K), viscosities and hardnesses to meet customer needs or grades tailor-made for customers.
They include ELASTOSIL® RT 7612 F TC, a two-component thermally conductive potting compound with a mixed viscosity as low as 1400 mPa·s and excellent flow properties. It is especially suitable for filling small and complex pores and cavities, such as gaps in inductor coils. After curing, the product demonstrates a low modulus and linear thermal expansion coefficient, as well as very good protection for stress-sensitive electronic components, such as magnetic cores of inductors. In addition, ELASTOSIL® RT 7612 F TC also features a certain degree of adhesion, which ensures reliable adsorption on the surface of the components, maintaining the integrity of the potted components with excellent aging resistance. It is an ideal potting material for the protection of OBC (on-board charger) power components.
ELASTOSIL® SC 8XX Series
The automatic dispensing silicone foam ELASTOSIL® SC 8XX series developed by WACKER provides a reworkable solution for battery module sealing. On one hand, the product can be automatically applied by dispenser, which makes automatic production possible. On the other hand, the glue only adheres to one cover plate. The upper and lower cover plates are fixed and attached by bolts which can be unscrewed for maintenance.
ELASTOSIL® SC 8XX demonstrates many excellent properties. ELASTOSIL® SC 873, for example, is flame retardant and is certified by SGS to UL 94 V0. It also has very good compression resilience. After various severe long-term aging tests (such as high temperature and high humidity, thermal shock and a temperature of 110°C for 1000 hours), its permanent compression set rate is less than 10%, an excellent resilience performance after aging, which is essential for the safety of the sealing. Experiment shows that components sealed with ELASTOSIL® SC 873 can still pass the IP 68 sealing test after long-term aging. Last but not least, it features very good thixotropy. ELASTOSIL® SC 873 can be used to produce narrow, highly adhesive strips, which saves housing space while maintaining sealing performance and reducing material costs.