US 11,916,230 B2
Negative electrode active material, negative electrode, alkaline storage battery, and method of producing negative electrode active material
Masato Hozumi, Mishima (JP); Motoyoshi Okumura, Nagoya (JP); Takeo Okanishi, Kariya (JP); and Atsushi Minagata, Kariya (JP)
Assigned to TOYOTA JIDOSHA KABUSHIKI KAISHA, Toyota (JP); and KABUSHIKI KAISHA TOYOTA JIDOSHOKKI, Kariya (JP)
Filed by TOYOTA JIDOSHA KABUSHIKI KAISHA, Toyota (JP); and KABUSHIKI KAISHA TOYOTA JIDOSHOKKI, Kariya (JP)
Filed on Nov. 19, 2019, as Appl. No. 16/688,241.
Claims priority of application No. 2018-229017 (JP), filed on Dec. 6, 2018.
Prior Publication US 2020/0185710 A1, Jun. 11, 2020
Int. Cl. C22C 19/03 (2006.01); H01M 4/38 (2006.01); H01M 10/24 (2006.01); H01M 4/02 (2006.01)
CPC H01M 4/383 (2013.01) [C22C 19/03 (2013.01); H01M 10/24 (2013.01); C22C 2202/02 (2013.01); H01M 2004/027 (2013.01)] 2 Claims
OG exemplary drawing
 
1. A method of producing an alkaline storage battery, comprising:
preparing a hydrogen storage alloy;
producing a negative electrode active material by heating the hydrogen storage alloy in an NaOH aqueous solution having a concentration of 44 mass % at a temperature of 105° C. or higher and 110° C. or less for an hour, and
preparing a negative electrode with the negative electrode active material,
wherein the hydrogen storage alloy has a chemical composition represented by the following
Formula (II): A2B7 (II)
where A includes La and Mg; and B includes Ni,
wherein the hydrogen storage alloy includes cobalt and 55 mass % or more and 65 mass % or less of nickel,
wherein a saturation magnetization per unit mass of the negative electrode active material is 5.3 emu·g−1 to 5.8 emu·g−1, and
wherein a direct current internal resistance of the alkaline storage battery is less than 40 with respect to a direct current internal resistance of a second alkaline storage battery including a negative electrode active material having a saturation magnetization per unit mass is 0.1 emu g−1 when a state of charge (SOC) of the first and second alkaline storage batteries is 50%.