The product offers cost-effective insulation through extrusion and, in case of fire, forms an electrically insulating ceramic layer to prevent short circuits, enhancing passenger and fire safety.
In a significant development for the electric vehicle (EV) industry, WACKER, a global chemical company, has announced a new silicone rubber designed to improve the safety and efficiency of high-voltage batteries. The product, named ELASTOSIL® R 531/60, is a flame-resistant material specifically engineered to insulate busbars—the conductive rails that distribute current within a battery pack. This innovation addresses the growing demands for robust insulation as battery voltages in EVs continue to rise.
As the EV market pushes for greater power, faster charging times, and extended ranges, battery voltages are trending upwards, with systems now operating in the range of 300 V to 900 V. This increase in voltage necessitates more reliable and durable insulation for critical components like busbars, which are typically made of aluminium or copper. ELASTOSIL® R 531/60 is designed to meet this challenge by providing a dependable barrier that prevents leakage currents and energy losses, even at operating temperatures as high as 205 °C.
One of the most crucial features of ELASTOSIL® R 531/60 is its ability to ceramify in the event of a fire. When exposed to extreme heat, the cured silicone rubber transforms into a solid, electrically insulating ceramic shell. This protective layer effectively sheathes the busbar, maintaining its insulation and preventing short circuits. This ceramifying property is vital for passenger and first responder safety, as it keeps the high-voltage system contained and minimizes the risk of electrocution during an accident or vehicle fire. The ceramic layer remains intact even at temperatures between 800 °C and 1000 °C, offering a new level of fire protection for electric vehicles.
Beyond its superior safety features, ELASTOSIL® R 531/60 also offers significant manufacturing advantages. The product can be processed via extrusion, a highly cost-effective method for applying insulation to busbars. This process allows for efficient, high-volume production, which is essential for the rapidly expanding EV market. The material's physical properties are also a key benefit for battery manufacturers. With a hardness of 60 Shore A, the silicone rubber is highly flexible and durable. It can withstand bending and molding to conform to the complex architectures of battery packs without cracking. Its high tear strength and notch impact resistance ensure that the insulation remains intact even after impacts or exposure to temperature fluctuations down to -40 °C. This flexibility also helps protect the battery from vehicle body vibrations and other mechanical stresses.
