Porous Power Technologies, LLC (PPT) has launched the SYMMETRIX NC2020, a ceramic battery separator designed to significantly improve thermal stability and safety of large-format lithium-ion batteries. Applications include batteries for electric vehicles, flat-cell consumer electronics, utility-grade energy storage, and other high-power or high-energy applications.
The battery separator is a vital component in the safety/cycle life/performance equation. SYMMETRIX NC2020, developed by PPT in partnership with Ahlstrom, delivers sizable improvements in all three areas, particularly safety.
“SYMMETRIX NC2020 is non-flammable and more resistant to shrinkage than conventional separators. This makes cells more stable when damaged or abused and can prevent or delay thermal runaway events,” says Michael Pender, PPT’s managing director.
“Use of ceramics in separators is not new,” explains John Shelburne, PPT’s director of Research and Development. “However, most manufacturers apply a ceramic coating on conventional polyolefin separators. A coating can impede ion flow through the separator, reducing battery cycle life and performance.” Further, it can crack or flake off, potentially contaminating the cell.
In contrast, SYMMETRIX NC2020’s ceramic particles are blended with PVDF polymer to form a flexible, ceramic-rich microporous membrane. Ions flow freely though the open pore structure, enabling cells with good power over broad temperature ranges. The sponge-like membrane conforms to the electrode surface to prevent dead spots and ensure reliable performance, even as electrodes expand and contract over many cycles.