Toray develops resin-film substrate for anode current collectors
- Toray developed the first film for anode current collectors that meets four requirements: resistance to reduction, metal-layer adhesion, mechanical strength and thermal stability.
- Anode film current collectors using the new resin substrate delivered battery performance comparable to conventional copper-foil collectors in cell evaluations.
- The standard-grade film is 4.5 µm thick, is 50–60% lighter than copper-foil collectors and can reduce battery cell weight by about 10%.
- Toray has produced the film on mass-production equipment, started customer sampling, and targets commercialization for small- and medium-sized batteries for mobile devices, drones and eVTOLs, with consideration for large EV and energy storage batteries.
Development
Toray developed a resin-film substrate for use in anode film current collectors that, it says, is the first to meet four key requirements simultaneously: resistance to reduction in the anode environment, strong adhesion to a metal layer, mechanical strength comparable to copper foil, and thermal stability. The material was created by structural control using polymer design and Toray’s polymer alloy film-formation technologies. The company notes PET is unsuitable on the anode side because it degrades under strongly reducing conditions.
Performance
Current collectors using the new film show excellent resistance to reduction, strong copper-layer adhesion, low thermal shrinkage and mechanical strength comparable to copper foil. In battery cell evaluations with single-layer laminate cells (30 mAh example), these collectors demonstrated performance comparable to conventional copper-foil anode collectors.
Manufacturing and specifications
Toray produced a standard-grade film at 4.5 microns using mass-production equipment, has begun providing samples to customers, and is exploring thinner gauges. The film is designed as a resin-film substrate for ultrathin metal-layer current collectors.
Impact and applications
The film reduces current-collector weight by 50–60%, which Toray estimates lowers battery cell weight by about 10%. Using the saved weight to increase active material (while keeping the N/P ratio constant) could increase EV range by up to 10% under certain conditions. Reduced copper usage may also help stabilise material costs. Toray plans to commercialise the film for small- and medium-sized batteries for mobile devices, drones and eVTOL aircraft and is considering applications for large EV and energy-storage batteries.
Source: Toray
