Toray Develops a Resin Film for Anode Current Collectors to Cut Battery Weight
The film is 50% to 60% lighter than conventional copper foil and could extend EV range by up to 10%.
Toray Industries has developed what it says is the first resin-film substrate for anode current collectors in lithium-ion batteries that meets all four key material requirements at once, potentially enabling a significant reduction in battery cell weight.
What Happened
The Japanese materials company built the new substrate using its polymer alloy technology to blend two or more polymers, achieving properties a single resin cannot. The film resists oxidation and reduction, bonds strongly to the copper layer, matches copper foil in mechanical strength and shows low thermal shrinkage. Toray says the film lets battery makers swap the copper foil that anodes conventionally use for a lighter film current collector coated with a thin copper layer. Battery cells using it performed comparably to conventional copper-foil collectors during testing.
Why It Matters
Current collectors are inactive mass, meaning they add weight without contributing to energy storage. Replacing copper foil with Toray's new resin film reduces the current collector weight by 50% to 60%, which the company says should cut overall battery cell weight by about 10%. That weight reduction can raise a cell's specific energy, extending run times for mobile devices and range for drones and vehicles. If the savings go toward more active material while keeping the negative-to-positive capacity ratio constant, Toray estimates the film could extend electric vehicle range by up to 10%.
The Bottom Line
Toray has produced a standard grade of the film at 4.5 microns thick on mass-production equipment and has begun sending samples to customers. The company plans to commercialize it in small and medium batteries for mobile devices, drones and eVTOL aircraft while studying use in larger batteries for EVs and energy storage.
