Matsushita Electric Industrial Co., Ltd.

Toyota Jidosha Kabushiki Kaisha

Panasonic Corporation

Other

Matushita Electric Industrial Co., Ltd.

Hajime Seri

Yoichiro Tsuji

Tsutomu Iwaki

Yasuharu Yamamura

Yoshio Moriwaki

Shinichiro Ito

Yoshinori Toyoguchi

Nobuyasu Morishita

Shinichi Yuasa

Kojiro Ito

Naoko Owada

Osamu Yamamoto

Kenichi Takeyama

Akemi Shintani

Yoshinori Yamada

Munehisa Ikoma

Teruhisa Kanbara

Toshihiro Yamada

A method of manufacturing a hydrogen-absorption alloy electrode which comprises particles of a hydrogen-absorption alloy that comprises a rare earth element, Ni, Co and Al. The method comprises subjecting the hydrogen-absorption alloy particles to an alkaline treatment in a 10 to 50 weight % NaOH solution at 60 to 140&#xb0; C. for 0.5 to 5 hours such that on the surface of the particles (amount of Al on surface/amount of Al in alloy)&#x3c;(amount of Co on surface/amount of Co in alloy).

Hydrogen-absorption alloy electrode

In a nickel-metal hydride rechargeable battery comprising a positive electrode of nickel hydroxide and a negative electrode of hydrogen-absorption alloy, prolonged battery life is achieved by limiting the charge and discharge operations to be performed in the range of 20-60% of the hydrogen-absorption capacity of the hydrogen-absorption alloy.

Nickel-metal hydride rechargeable battery

A negative electrode of a battery, chiefly includes hydrogen absorption alloy particles each having a surface layer. The alloy particles satisfy R/R&#x2267;0.004 and 5 &#x3bc;m&#x2266;R&#x2266;20 &#x3bc;m, or preferably 5 &#x3bc;m&#x2266;R&#x2266;12.5 &#x3bc;m, where Ris a half of a median diameter of the particles and Ris thickness of the surface layers.

Hydrogen absorption alloy electrode

A negative electrode of a battery, chiefly includes hydrogen absorption alloy particles each having a surface layer. The alloy particles satisfy R /R &gE;0.004 and 5 &mgr;m&lE;R &lE;20 &mgr;m, or preferably 5 &mgr;m&lE;R &lE;12.5 &mgr;m, where R is a half of a median diameter of the particles and R is thickness of the surface layers.

A method for charging a secondary battery is disclosed. The method comprises the steps of detecting an impedance of the battery; charging the battery with a substantially constant first current having a value smaller than a predetermined current value if the detected impedance of the battery is equal to or greater than a predetermined impedance value; charging the battery with a substantially constant second current having a value equal to or greater than the predetermined current value if the detected impedance is less than the predetermined impedance value; and terminating charging the battery with the first and second constant currents when the closed circuit voltage of the battery reaches a predetermined voltage value.

Method for charging lithium secondary battery

The present invention provides methods for detecting a working condition of a non-aqueous electrolyte secondary battery which allow easy and accurate determination of the degree of degradation and remaining capacity of the non-aqueous electrolyte secondary battery by a simple test irrespective of the past charging and discharging history of the battery. In the methods of the present invention, the degree of degradation of battery is quantitatively determined on the basis of the voltage value in charging or discharging at a constant current, or from an equation with that voltage value as variable.

Method for detecting working condition of non-aqueous electrolyte

Addition of Mo to a Zr--Mn--V--Cr--Co--Ni, a Zr--Mn--Cr--Co--Ni hydrogen storage alloy, or those including Ti as substitution for Zr improves high-rate discharge characteristics of the hydrogen storage alloy at low temperatures. The hydrogen storage alloy is of the general formula ZrMn.sub.a V.sub.b Mo.sub.c Cr.sub.d Co.sub.e Ni.sub.f, wherein 0.4.ltoreq.a.ltoreq.0.8, 0.ltoreq.b&lt;0.3, 0&lt;c.ltoreq.0.3, 0&lt;d.ltoreq.0.3, 0&lt;e.ltoreq.0.1, 1.0.ltoreq.f.ltoreq.1.5, 0.1.ltoreq.b+c.ltoreq.0.3, and 2.0.ltoreq.a+b+c+d+e+f.ltoreq.2.4, or Zr.sub.1-x Ti.sub.x Mn.sub.a V.sub.b Mo.sub.c Cr.sub.d Co.sub.e Ni.sub.f, wherein 0&lt;x.ltoreq.0.5, 0.4.ltoreq.a.ltoreq.0.8, 0.ltoreq.b&lt;0.3, 0&lt;c.ltoreq.0.3, 0&lt;d.ltoreq.0.3, 0&lt;e.ltoreq.0.1, 1.0.ltoreq.f.ltoreq.1.5, 0.1.ltoreq.b+c.ltoreq.0.3, x.ltoreq.b+c+d+e, and 1.7.ltoreq.a+b+c+d+e+f.ltoreq.2.2 or Zr.sub.1- Ti.sub.x Mn.sub.a Mo.sub.c M.sub.y Cr.sub.d Ni.sub.f, wherein M is at least one selected from the group consisting of Fe, Cu, and Zn, and wherein 0&lt;x.ltoreq.0.5, 0.4.ltoreq.a.ltoreq.0.8, 0&lt;c.ltoreq.0.3, 0.ltoreq.y.ltoreq.0.2, 0&lt;d.ltoreq.0.3, 1.0.ltoreq.f.ltoreq.1.5, and 1.7.ltoreq.(a+c+y+d+f).ltoreq.2.2. The alloy has a C15(MgCu.sub.2)-type Laves phase as a main alloy phase.

Hydrogen storage alloy and electrode therefrom

The present invention provides an improved hydrogen storage alloy of Ti--V--Ni system having a body-centered cubic structure. The alloy is of the general formula Ti.sub.x (V.sub.a Cr.sub.1-a).sub.1-x M.sub.b Ni.sub.c, wherein M represents at least one element of La and Ce or a mischmetal, and wherein 0.5.ltoreq.a.ltoreq.0.95, 0.01.ltoreq.b.ltoreq.0.1, 0.1.ltoreq.c.ltoreq.0.6, and 0.2.ltoreq.x.ltoreq.0.4; or Ti.sub.x V.sub.y M.sub.z Ni.sub.1-x-y-z, wherein M represents at least one element selected from the group consisting of Co, Fe, Cu, and Ag, and wherein 0.2.ltoreq.x.ltoreq.0.4, 0.3.ltoreq.y.ltoreq.0.7, 0.1.ltoreq.z.ltoreq.0.3, and 0.6.ltoreq.x+y+z.ltoreq.0.95.

In a method for producing a multi-component hydrogen storage alloy including metals of zirconium or vanadium, oxides of these metals is used to produce an alloy having characteristics equivalent to that produced with pure metals. It comprises steps of calcining the raw material, wherein at least one selected from the group consisting of zirconium and vanadium is included in its oxide form, at a temperature ranging from 900.degree. C. to 1300.degree. C., mixing metal calcium with said calcined raw material, and treating the mixture with heat at a temperature ranging from the melting point of metal calcium to 1300.degree. C., under inert gas atmosphere.

Method for producing hydrogen storage alloy

The present invention provides a hydrogen storing alloy electrode having a large discharging capacity and a long lifetime at a high temperature. The electrode is also excellent in discharging characteristics in the early charging and discharging cycles. In one aspect of the present invention, the hydrogen storing alloy electrode is made of a hydrogen storing alloy represented by the general formula ZrMn.sub.m V.sub.x X.sub.y Ni.sub.z or a hydride thereof, wherein X is Al, Zn or W; m, x, y, and z are respectively mole ratio of Mn, V, X, and Ni to Zr: 0.4.ltoreq.m.ltoreq.0.8, 0.1.ltoreq.x.ltoreq.0.3, 1.0.ltoreq.z.ltoreq.1.5, and 2.0.ltoreq.m+x+y+z.ltoreq.2.4; when X is Al or Zn, 0&lt;y.ltoreq.0.2; and when X is W, 0&lt;y.ltoreq.0.1. The alloy has mainly C15-type Laves phases with a crystal structure of MgCu.sub.2 type face center cubix. The alloy has a crystal lattice constant .alpha. 7.03 angstroms or more and 7.10 angstroms or less.

Hydrogen storing alloy electrode

A hydrogen storage alloy preferably used for electrodes in alkaline rechargeable battery is of the general formula: Zr.sub.1.2-a Ti.sub.a Mn.sub.v Al.sub.w Ni.sub.x M.sub.y Cr.sub.z wherein M represents at least one element selected from the group consisting of Si, Zn, Sn, Fe, Mo, Cu and Co; and wherein 0.1.ltoreq.a&lt;1.2, 0.4.ltoreq.v.ltoreq.1.2, 0&lt;w.ltoreq.0.3, 0.8.ltoreq.x.ltoreq.1.6, 0.ltoreq.y.ltoreq.0.2, 0.ltoreq.z.ltoreq.0.3, and 1.7.ltoreq.(v+w+x+y+z).ltoreq.2.7. The alloy has at least one of a C14-type Laves phase of a crystal structure similar to that of MgZn.sub.2 and a C15-type Laves phase of a crystal structure similar to that of MgCu.sub.2 as a main alloy phase.

A hydrogen storage alloy preferably used for electrodes in an alkaline storage battery is provided. The alloy is of the general formula ZrMn.sub.w V.sub.x Mo.sub.b M.sub.y Ni.sub.z, wherein M is at least one element selected from the group consisting of Fe and Co and 0.4.ltoreq.w.ltoreq.0.8, 0.ltoreq.x.ltoreq.0.3, 0.05.ltoreq.b.ltoreq.0.2, 0.ltoreq.y.ltoreq.0.2, 1.0.ltoreq.z.ltoreq.1.5, and 2.0.ltoreq.w+x+b+y+z.ltoreq.2.4. The alloy has C15-type Laves phases of a crystal structure similar to that of MgCu.sub.2 as a main alloy phase, and a lattice constant 'a' such that 7.05 .ANG..ltoreq.a.ltoreq.7.13 .ANG..

A hydrogen storage alloy electrode comprising a hydrogen storage alloy having a major phase of C15 (MgCu.sub.2) type Laves phase with a composition expressed as ZrMn.sub.w M.sub.x Cr.sub.y Ni.sub.z (where M is one or more elements selected from V and Mo), or its hydride. In this formula, one composition range is 0.6.ltoreq.w.ltoreq.0.8, 0.1.ltoreq.x.ltoreq.0.3, 0&lt;y.ltoreq.0.2, and 1.2.ltoreq.z.ltoreq.1.5, and the other composition range is 0.6.ltoreq.w.ltoreq.0.8, 0.1.ltoreq.x.ltoreq.0.3, 0&lt;y.ltoreq.0.2, and 0.8.ltoreq.z.ltoreq.1.2.

Hydrogen storage alloy electrodes

A hydrogen storage alloy preferably used for electrodes in an alkaline storage battery is provided. The alloy is of the general formula ZrMn.sub.w V.sub.x M.sub.y Ni.sub.z which comprises C15-type Laves phases having a crystal structure similar to that of MgCu.sub.2 as a main alloy phase, where M is an element selected from the group consisting of Fe and Co; w, x, y, and z are respectively the mole ratios of Mn, V, M and Ni to Zr; the conditions 0.4.ltoreq.w.ltoreq.0.8, 0.1.ltoreq.x.ltoreq.0.3, 0.ltoreq.y.ltoreq.0.2, 1.0.ltoreq.z.ltoreq.1.5 and 2.0.ltoreq.w+x+y+z.ltoreq.2.4 are satisfied.

Hydrogen storage alloy and hydride electrodes having C15 crystal

The present invention provides a hydrogen storage alloy electrode made of a pentanary or higher multi-component hydrogen storage alloy or a hydride thereof where the alloy comprises at least Zr, Mn, Cr, Ni, and M where M is one or more elements selected from V an Mo, and a major component of the alloy phase is C.sub.15 (MgCu.sub.2) type Laves phase. This hydrogen storage alloy electrode may be enhanced in its performance by subjecting the alloy after the production thereof to a homogenizing heat-treatment at a temperature of 900.degree. to 1300.degree. C. in vacuum or in an inert gaseous atmosphere.

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Izumiotsu, Japan

Hajime Seri