Product Focus: Asahi Kasei Showcases Flame-Retardant Nonwoven Fabric - Tech Briefs

Battery & Electrification INSIDER

The Japanese technology company Asahi Kasei exhibited its new material solution for enhanced EV battery safety at the Battery Show. A flame-retardant and highly flexible nonwoven fabric, LASTAN™ is an alternative to conventional materials for thermal runaway protection. It can be utilized in top covers, busbar protection sleeves, and other applications within the EV battery pack.

Although electric vehicles are becoming more common worldwide, battery safety is still a major concern for many car users. According to the latest “Asahi Kasei Automotive Consumer Survey,” 34 percent of non-EV owners in China see improved safety as a primary consideration in buying an electric vehicle. Against this background, global OEMs seek to further raise the safety of EV batteries, and the market for materials to prevent thermal runaway is expected to grow by some 15 percent annually from 2024 onward, with even further expansion of demand in the future.

In this context, there is increasing demand for materials in EV battery cover applications having excellent resistance against flames and particle blasts, as well as good electrical insulation properties. While mineral-based materials are generally used as protection against thermal runaway at present, such materials tend to be heavy and brittle. Being stiff, these materials are difficult to adapt to complex shapes, making processability an issue for automotive OEMs.

LASTAN™ is a non-mineral flame-resistant fabric made by air baking a special acrylic fiber at 200–300℃. It is characterized by high flame resistance and good electrical insulation, which are further 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. With these exceptional characteristics, LASTAN™ has been used for many years as an optimal material for failure prevention and safety in various industries.

Even when a 1,300 ℃ flame is applied, the temperature on the opposite side of LASTAN™ remains below 400 ℃. While a “limiting oxygen index” (LOI) value of 27 or higher is generally considered to indicate flame retardance, this material has an LOI value of 50 or higher. In UL94 flame retardance testing, LASTAN™ has obtained the highest rating of 5VA. No holes are formed in LASTAN™ even when it is exposed to a flame of 1,300 ℃ for one minute.

In addition to its high flame resistance, LASTAN™ 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™ also features outstanding processability, being highly flexible while maintaining its performance characteristics in sheets as thin as 0.8 mm. This makes it easily processed with ordinary tools, contributing to a simplified manufacturing process. The Battery Show Booth 3807

For more information, visit www.asahi-kasei.com .