US Patent 7435511 Nickel-metal hydride storage battery

A nickel-metal hydride storage battery having a spirally wound electrode group including: (a) a positive electrode including an active material layer containing nickel hydroxide and a positive electrode core material; (b) a negative electrode including an active material layer containing a hydrogen storage alloy and a negative electrode core material; and (c) a separator interposed between the positive and negative electrodes, wherein the separator includes a hydrophilicity-imparted non-woven fabric including polyolefin or polyamide and has a thickness of 0.04 to 0.09 mm, and the percentage occupied by the cross section “SS” of the separator in the transverse cross section “S” of the electrode group is not greater than 25%.