Patent ID: 7790306
Filing Date: 2010-09-07
Classification: H01M,Y02E

Abstract:
1. A nickel hydrogen storage battery, comprising: a spiral electrode assembly contained in a container with an alkaline electrolyte, the electrode assembly including a negative electrode plate containing hydrogen storage alloy particles and a nonaqueous polymer binder for binding the hydrogen storage alloy particles and having an effective surface area per unit capacity of 70 cm a positive electrode plate that is wound with the negative electrode plate in a spiral configuration and includes nickel hydroxide as positive active material, a first separator disposed between an outer surface of the positive electrode plate and an inner surface of the negative electrode plate, and a second separator disposed between an inner surface of the positive electrode plate and an outer surface of the negative electrode plate, wherein the first and second separators between the positive and negative electrode plates have a density in an inclusive range of from 450 kg/m each of the first and second separators is formed by subjecting a nonwoven fabric to hydrophilizing treatment, the nonwoven fabric of the first and second separators having a virtually circular cross-section and being formed by combining compound fibers and microfibers through a melting portion of the compound fibers, the compound fibers being constituted by polyolefin-based resin and having a diameter in an inclusive range of from 5 μm to 15 μm and an outer circumferential surface provided at least in a part thereof with the melting portion having a lower melting point than other portion, the microfibers being constituted by polyolefin-based resin and having a virtually circular cross-section and a diameter in a range of from 1 μm to less than 5 μm, wherein proportion of the microfibers to a blend of the microfibers and the compound fibers falls in a range of from 10 percent by mass to 20 percent by mass, and wherein at least one of the nonwoven fabrics of the first and second separators is subjected to sulfonation treatment as the hydrophilizing treatment.