Alkaline storage cell and hydrogen storage alloy for negative electrode of alkaline storage cell
AssigneeSanyo Electric Co., Ltd.
InventorsMasaru Kihara, Takahiro Endo, Tatsuya Aizawa
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Abstract
An alkaline storage cell has a positive electrode, a negative electrode containing a hydrogen storage alloy, and an alkaline electrolyte. The hydrogen storage alloy has a composition expressed by a general expression: Ln1-αMgαNiβ-γ-δTγAlδ, where Ln represents at least one element chosen from a group consisting of La, Ce, etc., T represents at least one element chosen from a group consisting of V, Nb, etc., and subscripts α, β, γ and δ represent numerical values which satisfy 0.05<α<0.12, 3.40≦β≦3.70, 0.01≦γ≦0.15 and 0.15≦δ≦0.35.
Claims14
An alkaline storage cell comprising:
- a positive electrode;
- an alkaline electrolyte;
- and
- a negative electrode containing a hydrogen storage alloy, the hydrogen storage alloy having a composition expressed by a general expression:
- Ln1-αMgαNiβ-γ-δTγAlδ
- (where Ln represents at least one element chosen from a group consisting of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Ca, Sr, Sc, Y, Ti, Zr and Hf, T represents at least one element chosen from a group consisting of V, Nb, Ta, Cr, Mo, Mn, Fe, Co, Zn, Ga, Sn, In, Cu, Si, P and B, and subscripts α, β, γ and δ represent numerical values which satisfy
- 0.05<α<0.12,
- 3.40≦β≦3.70,
- 0.01≦γ≦0.15 and
- 0.15≦δ≦0.35);
- wherein the hydrogen storage alloy includes
- a parent phase, in the parent phase a ratio (Cmin/Cave) of a minimum concentration (Cmin) of Mg to an average concentration (Cave) of Mg being greater than or equal to 0.4, and
- segregation phases, an area ratio of the segregation phases in a cross section of the hydrogen storage alloy being less or equal to 30%.
A hydrogen storage alloy for a negative electrode of an alkaline storage cell, having composition expressed by a general expression:
- Ln1-αMgαNiβ-γ-δTγAlδ
- (where Ln represents at least one element chosen from a group consisting of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Ca, Sr, Sc, Y, Ti, Zr and Hf, T represents at least one element chosen from a group consisting of V, Nb, Ta, Cr, Mo, Mn, Fe, Co, Zn, Ga, Sn, In, Cu, Si, P and B, and subscripts α, β, γ and δ represent numerical values which satisfy 0.05<α<0.12, 3.40≦β≦3.70, 0.01≦γ≦0.15 and 0.15≦δ≦0.35);
- wherein the hydrogen storage alloy includes
- a parent phase, in the parent phase a ratio (Cmin/Cave) of a minimum concentration (Cmin) of Mg to an average concentration (Cave) of Mg being greater than or equal to 0.4, and
- segregation phases, an area ratio of the segregation phases in a cross section of the hydrogen storage alloy being less than or equal to 30%.
Dependencies are inferred from the claim text.