Sanyo Electric Co., Ltd.

Shuhei Yoshida

Yoshinobu Katayama

Makoto Ochi

Kazuhiro Kitaoka

Kazuaki Tamura

Teruhito Nagae

Masao Takee

Yasuyuki Harada

Hiromasa Sugii

Atsutoshi Ako

Yoshihiro Masuda

A hydrogen-absorbing alloy for an alkaline storage battery with high power characteristics and excellent output power stability and a method for manufacturing the same are provided. The hydrogen-absorbing alloy for an alkaline storage battery of the invention is represented by AB(A: LaReMg, B: NiT, Re: at least one element selected from rare earth elements including Y (other than La), T: at least one element selected from Co, Mn, Zn, and Al, and z&#x3e;0) and has a stoichiometric ratio n of 3.5 to 3.8, a ratio of La to Re (x/y) of 3.5 or less, at least an ABtype structure, and an average C axis length &#x3b1; of crystal lattice of 30 to 41 &#x212b;.

Hydrogen-absorbing alloy for alkaline storage battery and method for manufacturing the same

An alkaline storage battery in which an actual reaction area is not reduced after increasing a reaction area is provided. A hydrogen storage alloy negative electrodeof an alkaline storage batteryof the present invention is formed in a strip form including a long axis and a short axis, in which the 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&#x2266;A/B&#x2266;30), and the ratio (X/Y) of an electrolyte volume X (g) retained in the hydrogen storage alloy negative electrodeto an electrolyte volume Y (g) retained in a separatoris 0.8 or more and 1.1 or less (0.8&#x2266;X/Y&#x2266;1.1). With this arrangement, an alkaline storage battery with high output characteristics and long-term durability performance is obtained.

Alkaline storage battery

Disclosed is an alkaline storage battery comprising a negative electrode, a positive electrode, a separator and an alkaline electrolyte solution in a package can. The negative electrode contains a hydrogen storage alloy represented by the following general formula: LnMg(NiT)(wherein Ln represents at least one element selected from lanthanoid elements, Ca, Sr, Sc, Y, Ti, Zr and Hf; T represents at least one element selected from V, Nb, Ta, Cr, Mo, Mn, Fe, Co, Al, Ga, Zn, Sn, In, Cu, Si, P and B; and 0&#x3c;x&#x2266;1, 0&#x2266;y&#x2266;0.5 and 2.5&#x2266;z&#x2266;4.5) as a negative electrode active material. In this alkaline storage battery, the hydrogen equilibrium pressure (P) is regulated to satisfy 0.02 MPa&#x2266;P&#x2266;0.11 MPa when the hydrogen amount stored in the hydrogen storage alloy (H/M (atomic ratio)) at 40&#xb0; C. is 0.5.

A hydrogen storage alloy used in a hydrogen storage alloy electrodehas a crystalline structure having a mixed phase made up of at least an ABtype structure and an ABtype structure, and a surface layer of hydrogen storage alloy particles is so formed as to have a nickel content ratio greater than that of a bulk. The ratio (X/Y) of the nickel content ratio X (% by mass) of the surface layer to the nickel content ratio Y (% by mass) of the bulk is greater than 1.0 but no more than 1.2 (1.0&#x3c;X/Y&#x2266;1.2). The gradient between the content ratio of the nickel in the surface layer of the hydrogen storage alloy particles and the content ratio of the nickel in the bulk is alleviated and a hydrogen storage alloy electrode with high output characteristics is obtained.

Hydrogen storage alloy electrode and alkaline storage battery using the same

To provide a hydrogen storage alloy for an alkaline battery capable of having high performance of power characteristics much more beyond the related-art range, and a production method thereof, as well as an alkaline battery by investigating the constituent ratios of the AB-type structure and the AB-type structure. The hydrogen storage alloy for an alkaline battery of the present invention includes: an element R selected from the Group IV and the rare earth elements including Y and excluding La; and an element M consisting of at least one of Co, Mn, and Zn. The hydrogen storage alloy is represented by general formula: LaRMgNiAlM(wherein &#x3b1;, &#x3b2;, &#x3b3;, &#x3b7;, &#x3b5; satisfy numerical formulae: 0&#x2266;&#x3b1;&#x2266;0.5, 0.1&#x2266;&#x3b2;&#x2266;0.2, 3.7&#x2266;&#x3b3;&#x2266;3.9, 0.1&#x2266;&#x3b7;&#x2266;0.3, 0&#x2266;&#x3b5;&#x2266;0.2); and the constituent ratio of the AB-type structure is 40% or more in the crystal structure thereof.

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Moriguchi, Japan

Shuhei Yoshida