Hydrogen storage alloy for use in alkaline storage batteries and method for production thereof
US6576367B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 26, 2000 |
| Grant date | Jun 10, 2003 |
| Priority date | — |
| Expiry date | Dec 26, 2020 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S420/90
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A hydrogen storage alloy, for use in alkaline storage batteries, having a CaCu5-type crystal structure and represented by the compositional formula MmNixCoyMnzMl-z (wherein M represents at least one element selected from the group consisting of aluminum (Al) and copper (Cu); x is a nickel (Ni) stoichiometry and satisfies 3.0≦x≦5.2; y is a cobalt (Co) stoichiometry and satisfies 0≦y≦1.2; z is a manganese (Mn) stoichiometry and satisfies 0.1≦z≦0.9; and the sum of x, y and z satisfies 4.4≦x+y+z≦5.4). The hydrogen storage alloy includes a bulk region having a CaCu5-type crystal structure and a substantially uniform composition and a surface region surrounding said bulk region and having a graded composition. When the sum in percentage of numbers of cobalt (Co) atoms and copper (Cu) atoms present in the surface region is given by a and that in the bulk region by b, the relationship a/b≧1.3 is satisfied.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.