Next Generation of Separator Coatings Beyond Ceramics for Fast Charging

High rates of charge or discharge generates extensive heat, which gets trapped inside the battery, creating hot spots and leading to premature failure when the battery is used for long periods of time. Today’s solutions to this problem involve coating the separator with an aluminum oxide, or alumina coating – which increases melting temperature and improves safety. This has been one of the major breakthroughs in the battery industry over the past several decades. However, ceramic-coated separators do not provide enough thermal performance needed for fast charging and high power applications specially in large cell where the heat dissipation is challenging. To address that problem, stating 2012, we have been developing a new class of separators coating, carbon-based coating, that is comparable in cost to ceramic coated separator but has 10 times the thermal conductivity and is safer – increasing the separator melting temperature by 100 deg C. This enhanced thermal conductivity will remove more heat during cycling, reduces hot spots and results in cell temperatures as much as 11 deg C lower during operation. PCS’s ability to remove heat will result in longer cycle life for EV batteries. The increased thermal performance means that PCS TM is safer than ceramic-coated separators, but the more important difference is the x10 thermal conductivity, which means that PCS TM facilitates heat removal from the center of the cell substantially more than other separators. The benefit is likely to be increased cycle life and higher rate capability. Figure 1