New Epoxy Prepreg Delivers Superior Flame Retardancy in Battery Enclosures

Solvay has launched SolvaLite 716 FR, a fast-curing epoxy prepreg system designed for a range of structural parts and reinforcements in premium battery electric vehicles (BEVs).

"The automotive industry sees a need for new material solutions for battery components with superior flame retardancy compared to conventional thermoset prepregs and aluminum, and which allow passengers sufficient escape time in the event of a thermal runaway," explains Stefano Montani, transportation marketing manager at Solvay. "Structural battery housing solutions must also ensure reliable [electromagnetic interference] shielding performance and enable efficient processing of large volumes at high production rates. Our new SolvaLite prepreg combines all these properties with a significant lightweighting potential compared to incumbent solutions."

SolvaLite 716 FR is primarily targeted at flame-retardant battery enclosure applications for premium and super-premium BEVs. It has a dry glass transition temperature (T_g) of 145°C (293°F) and has been shown to outperform aluminum and discontinuous-fiber composites in practical UL 2596 flammability tests by providing protection at a wall thickness of just 2 mm. Beyond the automotive industry, the new material also opens up potential for other components where fire safety is key to meeting general UL94 V-0 specifications.

This system is designed for rapid curing, offering a press cure time of eight minutes at 150°C (302°F). Higher temperature and shorter cycle time capability help converters achieve more efficient production routes, such as with Solvay’s proprietary double-diaphragm forming (DDF) technology. SolvaLite 716 FR is available in a highly customized range of formats and continuous-fiber types aimed at meeting demanding mechanical requirements, under worst-case loading conditions, minimizing component thicknesses and optimizing enclosure volume for increased volumetric energy density or vehicle z-height.

SolvaLite 716 FR will be commercially available by the end of 2023.