Hydrogen absorbing alloy, negative electrode comprising same and nickel-metal hydride secondary battery comprising same

Patent metadata

Field	Value
Publication number	US-11817573-B2
Application number	US-202117446285-A
Country	US
Kind code	B2
Filing date	Aug 27, 2021
Priority date	Aug 31, 2020
Publication date	Nov 14, 2023
Grant date	Nov 14, 2023

Abstract

A nickel-metal hydride secondary battery includes an outer can and a group of electrodes housed in the outer can together with an alkaline electrolytic solution. The group of electrodes includes a positive electrode and a negative electrode that are superposed with a separator interposed therebetween, and the negative electrode includes a hydrogen absorbing alloy for nickel-metal hydride secondary batteries, the hydrogen absorbing alloy having a single composition and composed of a plurality of crystal phases.

First claim

What is claimed is:

1. A negative electrode for nickel-metal hydride secondary batteries, the negative electrode comprising a hydrogen absorbing alloy, wherein the hydrogen absorbing alloy consists of a single chemical composition and is composed of a plurality of crystal phases, wherein the single composition is represented by a general formula: Ln 1-x Mg x Ni y-z Al z wherein Ln represents at least one element selected from Zr and rare earth elements, and the subscripts x, y, and z satisfy x≤0.30, 3.3≤y≤3.6, and z≤0.25, respectively.

2. The negative electrode according to claim 1 , wherein:
when an X-ray diffraction pattern for the plurality of crystal phases is measured by using Cu—Kα rays as an X-ray source, an intensity ratio A represented by I1/I2 is in a range of 0.02≤A<0.14 and an intensity ratio B represented by I3/I2 is in a range of 0.02<B<0.31, wherein I1 represents an intensity of a diffraction peak at 2θ=30.3°, I2 represents an intensity of a diffraction peak at 2θ=32.8°, and I3 represents an intensity of a diffraction peak at 2θ=31.5°.

3. The negative electrode according to claim 1 , wherein the Ln is La.

4. A nickel-metal hydride secondary battery comprising a container and a group of electrodes housed together with an alkaline electrolytic solution in the container, wherein the group of electrodes comprises a positive electrode and a negative electrode that are superposed on each other with a separator interposed therebetween, and the negative electrode is the negative electrode according to claim 1 .

Assignees

• Fdk Corp

Inventors

• OHATA Shota
• Ishida Jun
• Ehara Yuki
• Kihara Masaru

Classifications

• H01M4/134 Primary

  Electrodes based on metals, Si or alloys · CPC title

• C22C19/03

  based on nickel · CPC title

• H01M10/054

  Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium · CPC title

• C22C2202/04

  Hydrogen absorbing · CPC title

• H01M2004/027

  Negative electrodes · CPC title