Wacker: Ceramifying Silicone Improves Thermal Barriers for EV Batteries

Wacker has developed a ceramifying silicone designed to enhance heat and flame protection in thermal barriers for electric vehicle batteries. The material, part of the company's "Elastosil" CM product range, is suitable for flexible barrier systems and is intended to protect battery components from heat, flames, and hot gases in the event of a thermal runaway in individual battery cells.

Safety and fire protection are among the key requirements for battery developers and automotive suppliers in the electromobility sector. In the event of a battery failure, battery housings and other protective systems must shield heat and escaping gases long enough to allow occupants to evacuate the vehicle. In Europe, a protection period of five minutes is currently considered a relevant benchmark, while longer evacuation times are being discussed in parts of Asia.

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The silicone cures into a silicone elastomer after application and can be applied both to housing components and to flexible, fabric-like protective systems. At temperatures above 600°C, the material loses its elastic properties and forms a ceramic protective layer. This layer acts as a barrier against heat and hot gases. According to Wacker, thermal runaway tests with battery cells showed that a protective fabric coated with "Elastosil" CM was able to reduce the radiant energy of a 1,300°C flame to below 150°C.

In addition to its flame and heat resistance, the ceramified silicone exhibits intrinsic mechanical strength. As a result, the protective layer is also capable of retaining particles that may be ejected from a defective battery cell during a thermal runaway event.

More information: www.wacker.com

Wacker Chemie AG, München