Japanese chemical company Asahi Kasei is introducing a new flame-resistant and highly flexible nonwoven fabric, LASTAN, for thermal runaway protection in top covers, busbar protection sleeves and other applications within an EV battery pack.
Mineral-based materials are typically used for thermal runaway protection, but they tend to be heavy and brittle, making them difficult to adapt to complex shapes in vehicles. LASTAN is a flame-retardant, non-mineral fabric made by air-baking a special acrylic fiber at 200-300° C. Its high flame resistance and electrical insulation are improved by a special coating process that also augments abrasion resistance. This allows the material to provide effective protection against particle bombardment from venting gas.
The temperature on the opposite side of LASTAN remains below 400° C even when a 1,300° C flame is applied, and no holes form in the fabric. The material has a limiting oxygen index (LOI) value of 50 or higher, which is above the value of 27 or higher generally considered to indicate flame retardance. In UL94 flame retardance testing, LASTAN obtained the highest rating of 5VA.
The material is resistant to high-pressure impact by particles of 200-500 µm. It also provides electrical insulating capacity of up to 3.5 kV at a thickness of 1 mm. LASTAN is highly flexible while maintaining its performance characteristics in sheets as thin as 0.8 mm, making it easy to process with ordinary tools.
“Having integrated production of LASTAN currently in Japan, Asahi Kasei is considering production in the United States and other countries in the future,” the company said.
Source: Asahi Kasei
