Abstract: An electrode for the alkaline storage battery includes a binding agent containing thermoplastic xylene-formaldehyde resin. Since the thermoplastic xylene-formaldehyde resin is non-aqueous, it is not dissolved into moisture in the air or the alkaline electrolyte within the battery. The electrode is prepared by immersing an active-material-applied or -filled electrode substrate in a solution in which the thermoplastic xylene-formaldehyde resin is dissolved; immersing it in an emulsion of the thermoplastic xylene-formaldehyde resin with an emulsifier; or applying or filling a slurry of the active material with an emulsion of the thermoplastic xylene-formaldehyde resin to or in the electrode substrate. The electrode retains the active material using a binding agent which has excellent adhesion to the active material and imparts high binding capacity of the active materials with one another.

Abstract: A nickel-hydrogen storage battery having improved charge and discharge cycle characteristics even in high temperature, which has a negative electrode comprising a hydrogen absorbing alloy capable of electrochemically storing and releasing hydrogen, a positive electrode comprising nickel hydroxide as a main active material, and an alkaline electrolytic solution mainly comprising an aqueous potassium hydroxide solution, wherein the positive electrode contains a cobalt compound, a yttrium compound, and 100 ppm or more of lithium based on the total weight of the nickel hydroxide, the cobalt compound, and the yttrium compound.

Abstract: An alkaline storage battery including a group of spiral electrodes composed of positive and negative electrode plates spirally wound with a separator interposed therebetween and contained in a metallic cell casing used as an external terminal, wherein the group of spiral electrodes is formed at its central portion with a space defined by a winding core during the winding process of the electrode plates and is provided with a first current-collector welded to an upper end of one of the electrode plates and a second current-collector welded to a lower end of the other electrode plate, wherein the second current-collector is welded to an internal surface of the bottom of the cell casing without being welded to an end portion of the other plate located at the outermost periphery of the group of spiral electrodes, and wherein the other electrode plate at the outermost periphery of the group of spiral electrodes is pressed into contact with an internal peripheral wall of the cell casing.

Abstract: An alkaline storage battery including a group of spiral electrodes composed of positive and negative electrode plates spirally wound with a separator interposed therebetween and contained in a metallic cell casing used as an external terminal wherein the group of spiral electrodes is formed at its central portion with a space defined by a winding core during the winding process of the electrode plates and is provided with a first current-collector welded to an upper end of one of the electrode plates and a second current-collector welded to a lower end of the other electrode plate, wherein the second current-collector is welded to an internal surface of the bottom of the cell casing without being welded to an end portion of the other plate located at the outermost periphery of the group of spiral electrodes, and wherein the other electrode plate at the outermost periphery of the group of spiral electrodes is pressed into contact with an internal peripheral wall of the cell casing.

Abstract: A nickel-hydrogen storage battery having improved charge and discharge cycle characteristics even in high temperature, which has a negative electrode comprising a hydrogen absorbing alloy capable of electrochemically storing and releasing hydrogen, a positive electrode comprising nickel hydroxide as a main active material, and an alkaline electrolytic solution mainly comprising an aqueous potassium hydroxide solution, wherein the positive electrode contains a cobalt compound, a yttrium compound, and 100 ppm or more of lithium based on the total weight of the nickel hydroxide, the cobalt compound, and the yttrium compound.

Abstract: The method of manufacturing a hydrogen-absorbing alloy electrode according to this invention comprises the steps of: dissolving a particle surface of said hydrogen-absorbing alloy by a surface-treatment solution; and washing the hydrogen-absorbing alloy with the particle surface dissolved using an alkaline solution at a temperature of 30° C.˜40° C. The metal ions dissolved by the surface-treatment solution can be completely washed away by the alkaline solution so that they will not be precipitated onto the surface of the hydrogen-absorbing alloy again as the hydroxide.

Abstract: A hydrogen-absorbing alloy electrode is prepared by reducing an oxide or hydroxide residing on the surface of a hydrogen-absorbing alloy particle while the alloy particle is held in an atmosphere of a hydrogen gas maintained at a temperature where absorbing of a hydrogen gas does not substantially occur; cooling the atmosphere from a temperature where absorbing of the hydrogen gas does not substantially occur to a temperature where the equilibrium hydrogen pressure of the hyrogen-absorbing alloy is equal to the hydrogen pressure in the atmosphere of the hydrogen gas and thereafter vacuum-evacuating and removing the hydrogen gas so that the hydrogen-absorbing alloy particle is cooled to room temperature while the hydrogen gas is exhausted; and thereafter introducing argon, nitrogen or carbon dioxide gas into the atmosphere, thereby returning the atmosphere to normal atmospheric pressure; and immersing the hydrogen-absorbing alloy particle so prepared in a solution containing an oxidation inhibiting agent.

Abstract: The invention provides a method of producing hydrogen-absorbing alloy that can remarkably improve a high-rate discharge characteristic of a nickel-hydrogen alkaline storage cell at low temperature. This is achieved by a method of producing hydrogen-absorbing alloy for use in a nickel-hydrogen alkaline storage cell including the following steps of (a) immersing a hydrogen-absorbing alloy in an alkali treatment solution having a temperature of 60° C. or higher to subject a surface of the hydrogen-absorbing alloy to an alkali treatment; (b) after the step (a), adding a pH-adjusting agent and a reducing agent to the alkali treatment solution to treat the surface of the hydrogen-absorbing alloy using the alkali treatment solution; and (c) washing the hydrogen-absorbing alloy treated by the step (b).

Abstract: The present invention certainly provides a metal hydride storage cell having excellent cycle characteristic and a method of producing such a cell. In order to realize the objectives, the cell is produced under a condition which makes the particle size distribution y/x of the activated hydrogen absorbing alloy electrode below 0.90.

Abstract: A nickel-metal hydride storage cell is composed of a non-sintered positive electrode which is filled with a nickel active material whose particles are coated with cobalt compound layers of divalent or greater and a metal hydride electrode which is filled with a surface-treated hydrogen-absorbing alloy. In the cell, the positive electrode non-reactive capacity rate (represented by the Equation 1) and the negative electrode charge depth (represented by the Equation 2) after the initial charge/discharge are 16% or lower, and 80% or lower, respectively. This construction makes it possible to take larger actual cell capacity by setting the value of the negative electrode charge depth to the degree which causes no rise in the cell internal pressure, thereby expanding the capacity of the cell. positive electrode non-reactive capacity rate %=(positive electrode theoretical capacity−actual cell capacity)/positive electrode theoretical capacity×100  Eq.

Abstract: An electrode for the alkaline storage battery according to this invention includes a binding agent containing thermoplastic xylene-formaldehyde resin. Since the thermoplastic xylene-formaldehyde resin is non-aqueous, it will be not dissolved into water in the air or the alkaline electrolyte within the battery. In this case, the removal of the active material during the process of manufacturing the electrode or within the battery can be prevented by any of the techniques of immersing the active-material-applied or -filled electrode substrate in the solution of the thermoplastic xylene-formaldehyde resin dissolved; immersing it in the emulsion of the thermoplastic xylene-formaldehyde resin with an emulsifier; and applying or filling the active material slurry with the emulsion of the thermoplastic xylene-formaldehyde resin to or in the electrode substrate.

Abstract: The method of manufacturing a hydrogen-absorbing alloy electrode comprises: a step of reducing an oxide or hydroxide residing on the surface of a hydrogen-absorbing alloy particle while the alloy particle is held in an atmosphere of a hydrogen gas maintained at a temperature where absorbing of the hydrogen gas does not substantially occur; a step of naturally cooling atmosphere from the temperature where absorbing of the hydrogen gas does not substantially occur to the temperature where the equilibrium hydrogen pressure of the hydrogen-absorbing alloy is equal to the hydrogen pressure in the atmosphere of the hydrogen gas and thereafter vacuum-evacuating the atmosphere of the hydrogen gas so that the hydrogen-absorbing alloy particle is cooled to room temperature while the hydrogen gas is exhausted; a step of exhausting the hydrogen gas and cooling the atmosphere to room temperature and thereafter introducing at least one kind of gas selected from the group consisting of argon, nitrogen and carbon dioxide int

Abstract: The method of manufacturing a hydrogen-absorbing alloy electrode according to this invention comprises the steps of: dissolving a particle surface of said hydrogen-absorbing alloy by a surface-treatment solution; and washing the hydrogen-absorbing alloy with the particle surface dissolved using an alkaline solution at a temperature of 30° C.˜40° C. The metal ions dissolved by the surface-treatment solution can be completely washed away by the alkaline solution so that they will not be precipitated onto the surface of the hydrogen-absorbing alloy again as the hydroxide. In this case, the washing using the alkaline solution of which the temperature exceeds 40° C. dissolves an alloy component as well as the hydroxide. Therefore, the temperature of the alkaline solution used must be controlled at 40° C. or lower. On the other hand, if the temperature of the alkaline solution is lower than 30° C.

Abstract: An object of the present invention is to provide an effective hydrogen-absorbing alloy activation process which can enhance the electrochemical activity of a hydrogen-absorbing alloy and to provide a hydrogen-absorbing alloy electrode which, when used in a battery, ensures an excellent initial inner pressure characteristic, low-temperature discharge characteristic, high-rate discharge characteristic and cycle characteristic. In accordance with the present invention, a hydrogen-absorbing alloy electrode production process is provided which comprises an alloy activation treatment step of immersing a hydrogen-absorbing alloy in a strong acid treatment solution containing metal ions and, in the course of the pH rise of the acid treatment solution, adding an alkali to the acid treatment solution to promote the pH rise of the acid treatment solution.

Abstract: A rectangular battery having an electrode group which is inserted in a battery case having an airtight structure. The electrode group is formed by alternately stacking positive electrodes and negative electrodes via separators. The battery case is rectangular had has a closed bottom and an open part that is airtightly sealed by a cover. The outermost electrodes, which are located on both faces of the electrode group, are coated with an active material on a surface of a core. Furthermore, the outermost electrodes have the same polarity and the cores thereof directly contact an inside surface of the outer battery case. In one embodiment, the capacity of the outermost electrodes is smaller than the capacity of the inwardly disposed electrodes of the same polarity.

Abstract: An object of the present invention is to provide a method for producing a hydrogen-absorbing alloy electrode for an alkaline storage battery which is efficient and effective enough to improve the performance of the battery. The method according to the present invention comprises the steps of: preparing a powdery hydrogen-absorbing alloy; and washing the powdery hydrogen-absorbing alloy with a strong acid solution and then with a weak acid solution having a higher pH value than the strong acid solution for a two-stage acid treatment.

Abstract: The object of the present invention is to provide an acid treatment for enhancing the high-rate discharge characteristic, cycle characteristic, and other characteristics of a hydrogen-absorbing alloy electrode to a large extent. The object can be achieved by subjecting a hydrogen-absorbing alloy as a negative electrode active material to an acid treatment comprising the steps of acid-treating the surface of the hydrogen-absorbing alloy by using a metallic ion-containing treatment solution which contains metallic ions and whose initial pH is in the range of 0.5 to 3.0; and heat-treating the hydrogen-absorbing alloy in an atmosphere with the presence of hydrogen.

Abstract: A metal-hydrogen alkaline storage cell comprising a rare earth hydrogen absorbing alloy and positive and negative electrodes, wherein the rare earth hydrogen absorbing alloy contains praseodymium in a weight ratio of no more than about 3 weight percent based on the total weight of rare earth elements.