Patent ID: 8409753

Claim:
An alkaline storage battery comprising: an electrode group fabricated by rolling a positive electrode using nickel hydroxide as a main positive electrode active material and a hydrogen storage alloy negative electrode using a hydrogen storage alloy as a negative electrode active material into a spiral form with a separator keeping the two electrodes apart interposed therebetween; an alkaline electrolyte; and an outer can containing the electrode group and the alkaline electrolyte inside thereof; the hydrogen storage alloy negative electrode being formed in a strip form including a long axis and a short axis, in which a ratio (A/B) of a length A (cm) of the long axis to a length B (cm) of the short axis is 20 or more and 30 or less (20≦A/B≦30), a ratio (X/Y) of an electrolyte mass X (g) retained in the hydrogen storage alloy negative electrode to an electrolyte mass Y (g) retained in the separator being 0.8 or more and 1.1 or less (0.8≦X/Y≦1.1); the hydrogen storage alloy negative electrode including a hydrogen storage alloy used as a negative electrode active material, an adhesive paste made of a thermoplastic elastomer, and a carbon conductor; a ratio Z (m 2 /cm 3 ) of a surface area of the negative electrode (m 2 ) to a unit volume (1 cm 3 ) of a negative electrode active material is 31 m 2 /cm 3 or more and 117 m 2 /cm 3 or less (31 m 2 /cm 3 ≦Z≦117 m 2 /cm 3 ); the hydrogen storage alloy includes a component A composed of elements including at least a rare earth element and magnesium, and a component B composed of element(s) including at least nickel but excluding manganese and cobalt; and the hydrogen storage alloy has A 5 B 19 , A 2 B 7 and AB 5 type structures, and has a primary alloy phase of an A 5 B 19 type structure; wherein surface area Z (m 2 /cm 3 ) of a negative electrode per unit volume of an active material as calculated based on the following equation (1) using specific surface areas S 1 , S 2 , and S 3 (m 2 /g) determined by BET method in each component (hydrogen storage alloy, carbon conductor, thermoplastic elastomer) of an active material, additive amounts G 1 , G 2 , and G 3 (g) of each component, volume V (cm 3 ) of active material after rolling: Z (m 2 /cm 3 )=( S 1× G 1+ S 2× G 2+ S 3× G 3)/ V (1).