JP2014007149A - Alkali storage battery, and alkali storage battery system therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: an alkali storage battery which is improved in its initial output characteristic while keeping the high-temperature charging efficiency at least equal to a conventional one, and which allows the suppression of the reduction in output characteristic after having worn; and an alkali storage battery system with such an alkali storage battery used therein.SOLUTION: The alkali storage battery has, in its exterior can, an electrode group and an alkaline electrolyte. The electrode group includes: a sintered nickel positive electrode including nickel hydroxide as a primary positive electrode active material; a negative electrode; and a separator. The sintered positive electrode contains at least one element selected from rare earth elements including yttrium. Representing in a form of the ratio to nickel in the positive electrode active material, the content of the at least one element is 0.1 mass% or lower. The sintered positive electrode includes 0.15-0.65 mass% of at least one element selected from tungsten, molybdenum and niobium in a form of the ratio to nickel in the positive electrode active material.

Description

  The present invention relates to an alkaline storage battery suitable for high-power applications such as a hybrid vehicle (HEV), and in particular, an electrode comprising a sintered nickel positive electrode and a negative electrode, and a separator separating these sintered nickel positive electrode and negative electrode. The present invention relates to an alkaline storage battery having a group together with an alkaline electrolyte in an outer can.

  In recent years, the use of secondary batteries has expanded, and has come to be used over a wide range such as mobile phones, personal computers, electric tools, hybrid vehicles (HEV), and electric vehicles (EV). Among these, in particular, alkaline storage batteries have been used in high output applications such as hybrid vehicles (HEV), and many technical developments related to high output have been made.

  By the way, in applications such as a hybrid vehicle (HEV), not only high output but also high durability performance is required. Therefore, nickel salts such as nickel nitrate are impregnated in the pores of the porous sintered substrate. After that, a sintered nickel positive electrode is generally used, which is treated with an alkaline aqueous solution and filled with nickel hydroxide as an active material. Further, this positive electrode active material has yttrium and ytterbium to improve high-temperature charging efficiency. Rare earth elements such as lutetium and erbium are added. (Patent Document 1).

  However, when a rare earth element containing yttrium is added to the positive electrode, there is a problem in that the output decreases due to an increase in resistance, and after repeated partial charge / discharge cycles at a high rate, the yttrium compound or rare earth element compound is on the surface of the active material. Elution and uneven distribution in the battery cause a decrease in battery capacity and a further decrease in output (decrease in durability).

Moreover, in the alkaline storage battery used for vehicle use like a hybrid vehicle (HEV), the partial charge / discharge control system which sets an upper limit voltage and a minimum voltage and performs partial charge / discharge within the upper and lower limit voltage is generally used. However, when partial charge / discharge control is used for an alkaline storage battery, there is a problem that a memory effect appears as the cycle progresses, and the amount of available energy (partial charge / discharge capacity) decreases significantly. As a result of intensive studies by the inventors, it has been found that the memory effect can be reduced by adding an element such as tungsten to the electrolytic solution, but this alone is not sufficient for reducing the memory effect.

JP 2004-71304 A

  The present invention solves the above problems, and provides an alkaline storage battery that is excellent in output and durability while maintaining high temperature charging efficiency equal to or higher than that of the prior art, and less affected by the memory effect during partial charge / discharge. Objective.

In order to solve the above problems, the present invention provides an alkaline storage battery comprising an electrode group consisting of a sintered nickel positive electrode having nickel hydroxide as a main positive electrode active material, a negative electrode, and a separator together with an alkaline electrolyte in an outer can. The sintered positive electrode contains at least one element selected from rare earth elements containing yttrium in a mass ratio of 0.1 mass% or less in the positive electrode active material, and the sintered positive electrode It is characterized by containing at least one element selected from tungsten, molybdenum and niobium in a nickel ratio of 0.15 mass% to 0.65 mass% in the positive electrode active material.

  By reducing at least one element selected from rare earth elements including yttrium to 0.1 mass% or less with respect to nickel in the positive electrode active material, the resistance is reduced in the sintered positive electrode as described above. The output is greatly reduced and the output can be improved. Furthermore, even after repeated partial charge and discharge at a high rate, the elution and uneven distribution of yttrium compounds and rare earth element compounds on the active material surface can be improved.

  In addition, the sintered positive electrode contains at least one element selected from tungsten, molybdenum, and niobium in an amount of 0.15 mass% or more based on nickel in the positive electrode active material, so that yttrium and rare earth elements are contained. It is possible to suppress a decrease in high-temperature charging efficiency, which is a concern due to the reduction of the battery.

  At this time, if tungsten, molybdenum, or niobium is contained excessively in the positive electrode, the output decreases due to an increase in resistance. Therefore, the content of these elements in the positive electrode is preferably set to a nickel ratio of 0.65 mass% or less. .

  In addition, by reducing at least one element selected from rare earth elements including yttrium to 0.1 mass% or less with respect to nickel in the positive electrode active material, the crystal correlation expansion and contraction of the positive electrode active material during charge and discharge can be reduced. Tungsten, molybdenum, and niobium, which are prominent and effective in reducing the memory effect, are more easily incorporated into the positive electrode, and the effects of reduced partial charge / discharge capacity and output due to the memory effect after partial charge / discharge are reduced. Is possible.

  In addition, inclusion of tungsten, molybdenum, or niobium in the pores of the positive electrode active material increases the effect of improving the high-temperature charging efficiency. Therefore, these elements are preferably contained in the pores of the positive electrode active material.

  Moreover, it is known that the charging efficiency is improved by increasing the amount of sodium in the alkaline electrolyte, while the output characteristics are deteriorated. However, the content of rare earth elements including yttrium in the above sintered positive electrode In an alkaline storage battery using a sintered nickel positive electrode containing one or more of tungsten, molybdenum and niobium, good charging efficiency and output can be achieved by setting the sodium concentration to 0.6 mol / L to 4 mol / L. It becomes possible to realize the characteristics.

  Moreover, by reducing the zinc content of the sintered nickel positive electrode active material to 1 mass% or less, the crystal expansion and contraction of the positive electrode active material during charge and discharge is further expanded, and any element of tungsten, molybdenum, or niobium is positive electrode. It becomes easier to be taken into the active material, and it becomes possible to further reduce the influence of a decrease in partial charge / discharge capacity and a decrease in output due to the memory effect.

Further, the negative electrode used in the alkaline storage battery of the present invention is not limited to a cadmium negative electrode or a hydrogen storage alloy negative electrode, but is a hydrogen storage alloy, particularly a general formula of Ln _1-x Mg _x Ni _y-a-b Al. _a M _b (where, Ln is at least one element selected from rare earth elements including Y, Zr and Ti, and M is V, Nb, Ta, Cr, Mo, Fe, Ga, Zn) , Sn, In, Cu, Si, P, B, at least one element selected from 0.05 ≦ x ≦ 0.30, 0.05 ≦ a ≦ 0.30, 0 ≦ b ≦ 0. 50, 2.8 ≦ y ≦ 3.9) is preferred.

  As described above, the present invention can provide an alkaline storage battery that is excellent in output and durability while maintaining high temperature charging efficiency equal to or higher than that of the prior art.

It is sectional drawing which shows typically the nickel-hydrogen storage battery of this invention. It is the schematic which shows the structure of the alkaline storage battery system of this invention.

  Next, embodiments of the present invention will be described in detail below. However, the present invention is not limited to these embodiments, and can be appropriately modified and implemented without departing from the scope of the present invention.

1. Sintered nickel positive electrode A slurry obtained by kneading nickel powder with a thickener (for example, methylcellulose), polymer hollow microspheres (pore diameter 60 μm) and water is applied to the punched metal, and then 1000 ° C. in a reducing atmosphere. The resin was dissolved and disappeared by heating to a nickel sintered substrate. When the obtained porous nickel substrate was measured with a mercury intrusion porosimeter (Pascal 140 manufactured by Faisons Instruments), the porosity was 85%.

  Then, the sintered nickel positive electrode 12 filled with the positive electrode active material is obtained by repeating the impregnation treatment for impregnating the obtained nickel sintered substrate in the following impregnation liquid and the alkali treatment with the alkali treatment liquid a predetermined number of times. Produced.

  The nickel sintered substrate is immersed in an impregnation liquid α composed of nickel nitrate, cobalt nitrate, and zinc nitrate, and then immersed and reacted in an alkali treatment liquid (for example, an aqueous sodium hydroxide solution). It was converted to cobalt hydroxide and zinc hydroxide, then washed with water and dried. This cycle was repeated 6 times. Then, it was immersed in an impregnation liquid β composed of nickel nitrate and yttrium nitrate, and immersed and reacted in an alkali treatment liquid to convert into nickel hydroxide / yttrium hydroxide in the pores, and then washed and dried. By performing the above steps, a sintered nickel positive electrode 12 filled with an active material mainly composed of a prescribed amount of nickel hydroxide was obtained.

  At this time, by adjusting the amount of zinc nitrate in the impregnating liquid α and the amount of yttrium nitrate in the impregnating liquid β, the amounts of zinc (Zn) and yttrium (Y) (the mass ratio of nickel in the active material) are different. Sintered nickel positive electrode A (Y6%, Zn14%), sintered nickel positive electrode B (Y0.1%, Zn14%), and sintered nickel positive electrode C (Y0.1%, Zn1%) were obtained.

2. Hydrogen storage alloy negative electrode Ln (elements selected from rare earth elements including Y and Zr and Ti, this time being neodymium [Nd]), magnesium (Mg), nickel ( Ni) and aluminum (Al) are mixed at a predetermined molar ratio, the mixture is dissolved in an argon gas atmosphere, and the mixture is rapidly cooled to obtain Nd _0.9 Mg _0.1 Ni _3.3 Al _0. An ingot of a hydrogen storage alloy expressed as _.2 was produced.

Subsequently, the obtained hydrogen storage alloy ingot was subjected to heat treatment (homogenization) in an argon atmosphere to obtain a hydrogen storage alloy identified as an A ₂ B ₇ type structure.

Thereafter, this hydrogen storage alloy was mechanically pulverized in an inert atmosphere to obtain a hydrogen storage alloy powder of Nd _0.9 Mg _0.1 Ni _3.3 Al _0.2 . When the particle size distribution was measured with a laser diffraction / scattering type particle size distribution measuring device, the average particle size corresponding to 50% of the mass integral was 25 μm. Thereafter, 0.5 parts by mass of SBR (styrene butadiene latex) as a water-insoluble polymer binder and CMC (carboxymethyl cellulose) as a thickener are added to 100 parts by mass of the obtained hydrogen storage alloy particles. 0.03 part by mass, 0.5 part by mass of carbon black as an additive, and an appropriate amount of water (or pure water) were added and kneaded to prepare a hydrogen storage alloy slurry.

  The obtained hydrogen storage alloy slurry was applied to both sides of a negative electrode core made of punched metal (made of nickel-plated steel plate), dried at 100 ° C., and rolled to a predetermined packing density. Then, the hydrogen storage alloy negative electrode 11 filled with the hydrogen storage alloy active material was produced by cutting into a predetermined dimension.

3. Nickel-hydrogen storage battery (alkaline storage battery)
Subsequently, the sintered nickel positive electrode 12 (A, B, or C) and the hydrogen storage alloy negative electrode 11 produced as described above were used, and a separator 13 made of a polyolefin nonwoven fabric was interposed between them to form a spiral shape. A spiral electrode group was produced by winding the electrode assembly in a spiral shape. In addition, the core exposed part 12c of the nickel positive electrode 12 is exposed at the upper part of the spiral electrode group thus manufactured, and the core exposed part 11c of the hydrogen storage alloy electrode 11 is exposed at the lower part. ing. Next, the positive electrode current collector 15 is welded onto the core exposed portion 12c of the nickel electrode 12 exposed at the upper end surface of the obtained spiral electrode group, and the core body exposed at the lower end surface of the spiral electrode group. The negative electrode current collector 14 was welded to the part 11c to obtain an electrode body.

  Next, after the obtained electrode body is housed in a bottomed cylindrical outer can 16 in which iron is nickel-plated (the outer surface of the bottom surface becomes a negative electrode external terminal) 16, the negative electrode current collector 14 is attached to the outer can 16. Welded to the inner bottom. On the other hand, the current collector lead portion 15a extending from the positive electrode current collector 15 is also used as a positive electrode terminal, and welded to the bottom of the sealing body 17 having the outer periphery provided with the insulating gasket 18. The sealing body 17 is provided with a positive electrode cap 17a, and a pressure valve composed of a valve body 17b and a spring 17c which are deformed when a predetermined pressure is reached is disposed in the positive electrode cap 17a.

  Next, after forming the annular groove portion 16 a on the upper outer peripheral portion of the outer can 16, an alkaline electrolyte is injected, and the outer peripheral portion of the sealing body 17 is mounted on the annular groove portion 16 a formed on the upper portion of the outer can 16. An insulating gasket 18 was placed. Thereafter, the opening edge 16b of the outer can 16 is caulked, and the cycle of 9.6 Ah charging → aging → discharging (end voltage 0.9 V) is repeated twice, thereby producing the nickel-hydrogen storage battery 10 having a nominal capacity of 6 Ah. did.

  In this case, as shown in Table 1, the alkaline electrolyte is a mixed aqueous solution of sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium tungstate and having a concentration of 7.0 mol / L, and includes potassium (K), Sodium (Na) and lithium (Li) concentrations (mol / L) are K6.2, Na0.6, and Li0.2, and an electrolyte solution a that does not contain tungsten, and the electrolyte solution a has a tungsten content. Electrolytic solution b in which sodium tungstate is added to 0.4 mass% with respect to nickel of the positive electrode active material, and tungsten so that the amount of tungsten in electrolytic solution a is 1.7 mass% with respect to nickel in the positive electrode active material. The electrolyte solution c to which sodium acid was added and the concentrations (mol / L) of K, Na, and Li were K2.8, Na4, and Li0.2, Ten amount using an electrolytic solution d was added sodium tungstate so that 0.4 mass% of nickel contained in the positive electrode active material.

  At this time, when a battery is fabricated using the electrolytic solution b or the electrolytic solution d, 0.15 mass% (nickel ratio in the active material) of tungsten is contained in the pores of the positive electrode active material. When a battery is produced by using the positive electrode active material pores, tungsten is contained in 0.65 mass% (the nickel ratio in the active material) (about 40% of the tungsten in the electrolytic solution is active in the positive electrode). (Provided in the substance pores).

  Here, the battery using the sintered nickel positive electrode A and the electrolytic solution a is Comparative Example 1, the battery using the sintered nickel positive electrode B and the electrolytic solution a is Comparative Example 2, the sintered nickel positive electrode A and the electrolytic solution The battery using b is comparative example 3, the battery using the sintered nickel positive electrode B and the electrolytic solution b is example 1, the battery using the sintered nickel positive electrode B and the electrolytic solution c is example 2, and the battery is sintered. A battery using the nickel positive electrode B and the electrolytic solution d was designated as Example 3, and a battery using the sintered nickel positive electrode C and the electrolytic solution b was designated as Example 4.

4). Battery Test Next, the following performance evaluation tests were performed using the batteries of Examples and Comparative Examples produced as described above.
(1) Output characteristic evaluation It charged to SOC (charge depth) 50% with the charging current of 1C in the temperature atmosphere of 25 degreeC. Thereafter, the charge / discharge current was increased in the order of 20A charge → 40A discharge → 40A charge → 80A discharge → 60A charge → 120A discharge → 80A charge → 160A discharge → 100A charge → 200A discharge. At this time, a pause period of 30 minutes was provided between each step, and charging / discharging was performed in the order of charging for 20 seconds → pause for 30 minutes → discharge for 10 seconds → pause for 30 minutes. The battery voltage at the time when 10 seconds had elapsed from this discharge was plotted against the charging current, and the current value when the straight line obtained by the least square method reached 0.9 V was calculated as the output (A).

(2) Evaluation of high-temperature charging efficiency Charging to SOC 80% with a charging current of 0.5C in a temperature atmosphere of 55 ° C, and immediately after discharging to a final voltage of 0.9V with a discharging current of 1C at 1.0V The discharge capacity of was determined. The ratio of the discharge capacity to the charge capacity at this time was calculated as the charge efficiency (%).

(3) Durability Performance Evaluation After charging at a charging current of 10 C to a voltage at which the SOC with respect to the initial battery capacity measured above is 80% in a temperature atmosphere of 50 ° C., the SOC is 20% at a discharging current of 10 C. A partial charge / discharge cycle test was repeated, in which a cycle of discharging to a voltage as follows was repeated. Such a partial charge / discharge cycle was repeated until the initial output ratio reached 60%, and the total amount of discharge electricity until the initial output ratio reached 60% was evaluated as durability.

(4) Memory effect influence evaluation After charging to a voltage at which the SOC with respect to the initial battery capacity measured above is 80% in a temperature atmosphere of 50 ° C. at a charging current of 10 C, the SOC is 20 at a discharging current of 10 C. A partial charge / discharge cycle test was repeated in which the cycle of discharging to a voltage of% was repeated, and the initial ratio of the partial charge / discharge capacity after the repetition until the total discharge electricity amount was 25 kAh was evaluated as the partial charge / discharge capacity maintenance rate.

5. Test results (Comparative Example 1)
A sintered nickel positive electrode in which the yttrium (Y) content in the positive electrode is 6 mass% with respect to nickel (Ni) in the active material and the positive electrode active material does not contain tungsten (W), potassium hydroxide, In Comparative Example 1, which is an alkaline storage battery that is a mixed aqueous solution of sodium hydroxide and lithium hydroxide and produced using an alkaline electrolyte having a sodium (Na) concentration of 0.6 mol / L in the electrolyte, The high temperature charging efficiency was not sufficient, and the durability had to be improved.

(Comparative Example 2)
In Comparative Example 2 in which the yttrium content in the positive electrode is reduced to 0.1 mass% with respect to nickel in the active material as compared with Comparative Example 1, resistance is reduced with respect to Comparative Example 1 by reducing yttrium. Initial output is improved.
In addition, durability is improved because there is no elution or uneven distribution of the yttrium compound on the surface of the positive electrode active material even after repeated high-rate partial charge / discharge.
However, there is a problem that the high-temperature charging efficiency is greatly reduced due to the reduction of yttrium.

(Comparative Example 3)
In Comparative Example 3 in which tungsten was contained in the positive electrode active material pores in the positive electrode active material pores in an amount of 0.15 mass% with respect to nickel in the active material, the positive electrode active material pores were contained in the positive electrode active material pores during charging of the positive electrode. Therefore, high temperature charging efficiency is improved.
In addition, oxygen generated at the positive electrode is reduced at the negative electrode, and it is known that the battery rapidly generates heat by this reduction reaction. Therefore, by improving the high-temperature charging efficiency, the amount of heat generated by the battery during charging is reduced, deterioration of the positive electrode material is suppressed, and durability is improved.
However, since tungsten is a slight resistance component, there is a problem that the output is slightly reduced.
In addition, there is a problem that the partial charge / discharge capacity is significantly reduced after the cycle due to the influence of the memory effect.

Example 1
Compared to Comparative Example 1, the yttrium content in the positive electrode is reduced to 0.1 mass% with respect to nickel in the active material, and tungsten is contained in the positive electrode active material pores at 0.15 mass% with respect to nickel in the active material. In Example 1, the output is improved compared to Comparative Example 1 by reducing yttrium, and in addition, the durability is greatly improved by the effect of yttrium reduction and tungsten.
Further, the decrease in charging efficiency, which is a concern due to yttrium reduction, is suppressed by the effect of tungsten.
In addition, the reduction of yttrium expands the crystal expansion and contraction of the positive electrode active material during charging and discharging, and the amount of tungsten taken into the positive electrode pores after the cycle is increased compared to Comparative Example 3; The discharge capacity maintenance rate is improved.

(Example 2)
In Example 2, in which the amount of tungsten in the positive electrode active material pores was increased to 0.65 mass% with respect to nickel in the active material as compared with Example 1, the effect of increasing the amount of tungsten was higher than that in Example 1. Charging efficiency increases and durability is greatly improved.
Although the output decreases with an increase in the amount of tungsten, if the amount of tungsten in the positive electrode active material pores is 0.65 mass% with respect to nickel in the active material, an output equal to or higher than that of Comparative Example 1 can be obtained due to the effect of reducing yttrium. .

(Example 3)
In Example 3, in which the sodium concentration in the electrolytic solution is increased to 4 mol / L compared to Example 1, the high-temperature charging efficiency is increased compared to Example 1 due to the effect of increasing the amount of sodium, and the durability is also improved.
The output decreases as the amount of sodium increases, but if the sodium concentration in the electrolyte is up to 4 mol / L, an output equivalent to or higher than that of Comparative Example 1 can be obtained due to the effect of reducing yttrium.

Example 4
In Example 4 in which the zinc content in the positive electrode active material was reduced to 1 mass% with respect to nickel in the active material as compared to Example 1, the crystal expansion and contraction of the positive electrode active material during charge / discharge was further increased compared to Example 1. As a result, the amount of tungsten taken into the positive electrode pores after the cycle is further increased as compared with Example 1, and the partial charge / discharge capacity retention ratio after the cycle is improved as compared with Example 1.

  In addition, although the example in which the yttrium content in the positive electrode is reduced and tungsten is contained in the positive electrode active material pore has been described, the case where the rare earth element content in the positive electrode is reduced or in the positive electrode active material pore It has been confirmed that the same effect is exhibited even when molybdenum or niobium is contained in.

  As described above, the content of rare earth elements including yttrium in the sintered positive electrode is reduced to a nickel ratio of 0.1 mass% or less, and any one selected from tungsten, molybdenum, and niobium in the pores of the positive electrode active material. By containing more than seed elements in a nickel ratio of 0.15 mass% to 0.65 mass%, it is possible to improve the output, high-temperature charging efficiency and durability compared to the past, and to suppress the memory effect during partial charge / discharge. I understood.

At this time, in order to maintain a balance between the output, high-temperature charging efficiency, and durability, the sodium concentration in the alkaline electrolyte is preferably 0.6 mol / L to 4 mol / L. In order to further suppress the influence of the memory effect, it has been found preferable to reduce the amount of zinc in the positive electrode active material to a nickel ratio of 1 mass% or less.

6). Alkaline storage battery system Next, an alkaline storage battery system constituted by combining a plurality of the batteries of Example 1 manufactured as described above was manufactured.

  The alkaline storage battery system is controlled so that the alkaline storage battery is charged / discharged only in the range of SOC 20 to 80%, and can effectively prevent the low SOC or high SOC state, and the durability of the alkaline storage battery. There is a merit that improves.

  Further, when the alkaline storage battery of the present invention is used in the alkaline storage battery system having the above configuration, the reaction resistance is low, so the heat generation of the battery accompanying charging / discharging is suppressed, and in addition, the yttrium compound on the active material surface after the charging / discharging cycle is suppressed. Since there is no elution or uneven distribution, the durability can be further improved.

  For this reason, it can be said that the alkaline storage battery of this invention is suitable for the alkaline storage battery system of the said structure.

  The specific configuration of the alkaline storage battery system having the above configuration is as follows. That is, an alkaline storage battery system 100 configured by combining a plurality of nickel-hydrogen storage batteries 10 manufactured as described above will be described below with reference to FIG. Here, as shown in FIG. 2, the alkaline storage battery system 100 of the present invention has a power supply 101 and 30 battery modules in which 8 unit cells made of the nickel-hydrogen storage battery 10 are connected in series. The assembled battery 102 is formed.

  Between the power source 101 and the assembled battery 102, a current and voltage from the power source 101 are converted into a predetermined constant current and constant voltage and supplied to the assembled battery 102, and a current flowing through the assembled battery 102 From the current detection circuit 104 for detecting the battery voltage, the voltage detection circuit 105 for detecting the battery voltage of the assembled battery 102, the discharge control unit 106 for controlling the forced discharge of the assembled battery 102, the current detection circuit 104 and the voltage detection circuit 105. A microcomputer 107 composed of a CPU or the like that controls the operation of the charge control unit 103 and the discharge control unit 106 is connected based on the detected value. The discharge controller 106 is connected to a discharge resistor for discharging the assembled battery 102, and the microcomputer 107 is connected to a timer 108 for measuring a predetermined time. The microcomputer 107 includes a partial charge / discharge control circuit, and is controlled such that the nickel-hydrogen storage battery 10 is partially charged / discharged.

  Further, the partial charge / discharge control in the alkaline storage battery system 100 having the above-described configuration is such that the alkaline storage battery is charged / discharged only when the SOC is in the range of 20 to 80%, so that the nickel-hydrogen storage battery 10 is low. There is a merit that the SOC or high SOC state can be effectively prevented and the durability of the nickel-hydrogen storage battery 10 is improved. Furthermore, when the alkaline storage battery of the present invention is used in the alkaline storage battery system 100 having the above configuration, the charge efficiency is high, so that the voltage change after the charge / discharge cycle hardly occurs and the partial charge / discharge control becomes easy. Furthermore, since the reaction resistance is low, heat generation of the battery due to charging / discharging is suppressed and a long life can be achieved. For this reason, it can be said that the alkaline storage battery of this invention is suitable for the alkaline storage battery system of the said structure.

DESCRIPTION OF SYMBOLS 10 ... Nickel-hydrogen storage battery, 11 ... Hydrogen storage alloy electrode, 11c ... Core body exposed part, 12 ... Nickel electrode, 12c ... Core body exposed part, 13 ... Separator, 14 ... Negative electrode collector, 15 ... Positive electrode collector , 15a ... current collecting lead part, 16 ... outer can, 16a ... annular groove part, 16b ... opening edge, 1
DESCRIPTION OF SYMBOLS 7 ... Sealing body, 17a ... Positive electrode cap, 17b ... Valve plate, 17c ... Spring, 18 ... Insulation gasket, 100 ... Alkaline storage battery system, 101 ... Power supply, 102 ... Assembly battery, 103 ... Charge control part, 104 ... Current detection part , 105 ... voltage detection unit, 106 ... discharge control unit, 107 ... microcomputer, 108 ... timer

Claims (4)

An alkaline storage battery comprising an electrode group composed of a sintered nickel positive electrode having nickel hydroxide as a main positive electrode active material, a negative electrode and a separator together with an alkaline electrolyte in an outer can,
The sintered positive electrode contains at least one element selected from rare earth elements including yttrium in a nickel ratio of 0.1 mass% or less in the positive electrode active material,
An alkali characterized in that the sintered positive electrode contains at least one element selected from tungsten, molybdenum, and niobium in a nickel ratio of 0.15 mass% to 0.65 mass% in the positive electrode active material. Storage battery.   The alkaline storage battery according to claim 1, wherein the alkaline electrolyte has a sodium concentration of 0.6 mol / L to 4 mol / L.   The alkaline storage battery according to claim 1, wherein the content of zinc in the active material of the sintered nickel positive electrode is 1 mass% or less in terms of nickel ratio in the positive electrode active material.   An alkaline storage battery system comprising the alkaline storage battery according to any one of claims 1 to 3, wherein the alkaline storage battery is subjected to partial charge / discharge control.

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