| US 7,501,207 B2 | ||
| Hydrogen absorbing alloy and secondary battery | ||
| Isao Sakai, Yokohama (Japan); Tatsuoki Kohno, Tokyo (Japan); Shirou Takeno, Yokohama (Japan); Takamichi Inaba, Yokohama (Japan); Hideki Yoshida, Yokohama (Japan); Masaaki Yamamoto, Inzai (Japan); Hirotaka Hayashida, Fujisawa (Japan); Shusuke Inada, Yokohama (Japan); Hiroshi Kitayama, Fujisawa (Japan); Motoya Kanda, Yokohama (Japan); Fumiyuki Kawashima, Matsudo (Japan); and Takao Sawa, Yokohama (Japan) | ||
| Assigned to Kabushiki Kaisha Toshiba, Tokyo (Japan) | ||
| Filed on Apr. 25, 2007, as Appl. No. 11/740,044. | ||
| Application 11/740044 is a division of application No. 11/290590, filed on Dec. 01, 2005, granted, now 7,300,720. | ||
| Application 11/290590 is a division of application No. 10/180522, filed on Jun. 27, 2002, granted, now 7,005,212. | ||
| Application 10/180522 is a continuation of application No. PCT/JP99/07318, filed on Dec. 27, 1999. | ||
| Prior Publication US 2007/0190417 A1, Aug. 16, 2007 | ||
| Int. Cl. H01M 4/38 (2006.01); C22C 19/00 (2006.01) | ||
| U.S. Cl. 429—218.2 [420/900] | 16 Claims |
| 2. A hydrogen absorbing alloy comprising a composition represented by general formula (3) given below,
wherein a parallel growth region precipitates in at least one crystal grain of a principal phase, the parallel growth region
having a crystal structure differing from a crystal structure of the principal phase, and an intensity ratio calculated by
formula (2) given below is lower than 0.15 including 0:
I1/I2 (2)
where I2 is an intensity of a highest peak in a X-ray diffraction pattern using a CuKα ray, and I1 is an intensity of a highest peak appearing at a value of 2θ falling within a range of from 8° to 13° in the X-ray diffraction
pattern, θ being a Bragg angle;
R1-a-bMgaTbNiZ-XM3X (3)
where R is at least one element selected from rare earth elements, said rare earth elements including Y, T is at least one
element selected from the group consisting of Ca, Ti, Zr and Hf, M3 is at least one element selected from the group consisting
of Co, Mn, Fe, Al, Ga, Zn, Sn, Cu, Si, B, Nb, W, Mo, V, Cr, Ta, Li, P and S, the atomic ratios of a, b, X and z are respectively
satisfy conditions of: 0.15≤a≤0.37, 0≤b≤0.1, 0.53≤(1−a−b) ≤0.85, 0≤X≤2 and 3≤Z≤4.2.
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