Protective Anode Separators for Rechargeable Lithium Cells

The anode separators in rechargeable lithium-ion electrochemical cells that contain carbon lithium-intercalating anodes with copper current collectors would be modified, according to a proposal, to give some protection against the internal short-circuiting that tends to occur during overdischarge. The carbon anodes offer advantages of greater safety and chemical stability over anodes made of pure lithium, but they also introduce a need to limit discharge, as explained below. The modified anode separators would not obviate the need to limit discharge, but would help to retard or prevent internal short-circuiting when overdischarge occurs despite efforts to prevent it.