Enhancing Safety in Electric Vehicles: TEGO® Therm-based heat-protective and fire-resistant coatings for battery housings

As the electric vehicle (EV) market continues its rapid expansion, the demand for safer and more efficient battery technologies becomes increasingly important. The goal is to reduce the risk of fires resulting from infrequent but hazardous thermal runaway incidents in EV batteries. Thermal runaway starts in a battery cell and can be triggered by a short circuit, cell malfunction, or external mechanical failure leading to a rapid increase in temperature and potential ignition. Industry faces stringent safety standards to mitigate these risks, necessitating advanced thermal insulation solutions. Evonik addresses this challenge with its cutting-edge TEGO® Therm based heat protective and fire-resistant coatings designed for EV battery housings and covers.

Evonik's TEGO® Therm product line offers a robust response to the industry's safety demands. These coatings provide superior thermal insulation and fire resistance, crucial for preventing thermal runaway in EV batteries. The TEGO® Therm coatings are engineered to meet and exceed the UL 94 V-0 fire safety standards, ensuring a high level of protection for electric vehicle batteries.

The TEGO® Therm coatings are designed for easy spray application, allowing for complete and efficient coverage of complex three-dimensional battery housings. This versatility ensures that every contour of the battery housing is protected, providing a uniform barrier against heat and fire.

The TEGO® Therm toolbox includes a variety of components, each meticulously engineered to enhance the performance of thermal insulation and fire-resistant coatings:

Coatings based on this range of products meet the UL 94 V-0 fire safety standards, providing a new level of protection for EV batteries. The versatility of TEGO® Therm allows for spray application on complex three-dimensional substrates, ensuring complete and efficient fire resistance of the coverage of every contour of the battery housing.

During rigorous testing, coatings formulated with TEGO® Therm demonstrated their ability to minimize heat transfer to the underlying substrate while preserving superior mechanical integrity during direct exposure to flames.

Coatings based on TEGO® Therm L 300 binder combined with TEGO® Therm HPG granules can reach a thermal conductivity (λ value) of less than 40 mW/(m K).

During the test the coating based on TEGO® Therm was subjected to stress by a propylene flame for a period of 25 minutes, which can reach temperatures of over 1000 °C. To be able to assess this accurately, the temperature on the back of the steel substrate was meticulously measured. This experiment was carried out with two different dry film thicknesses of the coating in order to compare their respective fire protection properties. 

When exposed to a direct jet flame with temperatures exceeding 1,000 °C, the temperature increases gradually, and the maximum temperature on the reverse side remains below 250°C with a dry film thickness of just 2.0 mm. Increasing the dried film thickness to 5 mm further lowers the back panel temperature to 110°C.

The tests show that thin coatings with a dry film thickness (DFT) of only a few millimeters, suitable for applications with limited space, enable effective insulation and protection of the substrate.

As electric vehicles become more prevalent, the demand for improved battery safety will only grow. Evonik's TEGO® Therm fire-resistant coatings provide a vital solution to one of the industry's most pressing challenges. By enhancing the safety and reliability of EV batteries, these coatings contribute to the broader goal of sustainable and secure electric mobility. As the market evolves, innovations like TEGO® Therm will play a pivotal role in ensuring that electric vehicles are not only efficient but also safe for consumers worldwide.