JP3209071B2 - Alkaline storage battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an electrode plate and a spiral electrode group of an alkaline storage battery.

[0002]

2. Description of the Related Art A typical example of an alkaline storage battery is a nickel-cadmium storage battery (hereinafter referred to as a nickel-cadmium battery). When comparing Ni-Cd batteries and lead-acid batteries as power sources for portable equipment, Ni-Cd batteries have a higher energy density per unit weight and unit volume, and are superior in reliability such as cycle life. It is widely used as a power source.

[0003] However, a storage battery having the same reliability as that of a nickel-cadmium battery and having a high energy density has been desired as a power source for portable equipment. In recent years, high-capacity NiCd batteries with 1.3 times or more the capacity of conventional NiCad batteries, and electrochemically large amounts of hydrogen storage / release reactions (charge / discharge reactions) have become possible in place of the cadmium negative electrode of NiCad batteries. A nickel-hydrogen storage battery using a suitable hydrogen storage alloy or a nickel-zinc storage battery using zinc has attracted attention.

[0004] Among these alkaline storage batteries, high-capacity type batteries mainly use a paste-type electrode as a nickel positive electrode. Among them, a paste-like active material mainly composed of nickel oxide is used for a sponge-like nickel porous body. In a paste-type positive electrode uniformly filled with a substance, the capacity density of the electrode plate reaches 600 mAh / cc or more.

As the negative electrode, a material in which cadmium, a hydrogen storage alloy, zinc, or the like, which is an active material, is paste-formed and uniformly applied to both the front and rear surfaces of a porous steel plate or a metal net and rolled is used.

[0006]

In order to further increase the capacity of the alkaline storage battery and improve the energy density per unit volume, it is necessary to increase the amount of the positive electrode active material (occupied volume) that regulates the battery capacity. However, in order to increase the amount of the positive electrode active material in the limited internal volume of the battery container, the volume occupied by other constituent materials such as the negative electrode active material, the positive / negative electrode support, the separator, and the like are increased by the increased amount of the positive electrode active material. It must be relatively reduced.

In consideration of this point, when the capacity of a battery is increased by a conventional method for producing a battery using positive and negative plates filled or coated with an active material to a uniform thickness, the following problems occur. It is concerned.

That is, when the amount of the negative electrode active material is reduced, the capacity ratio between the positive electrode active material and the negative electrode active material becomes unbalanced, and it becomes difficult to smoothly proceed the electrode reaction, which causes a problem in the discharge characteristics. This tendency becomes more remarkable when the discharge current value is large. In addition, when the amount of the negative electrode active material is reduced, the battery characteristics such as the rapid charging characteristics due to the reduction of the gas absorption capacity of the negative electrode at the time of overcharging and the resulting life characteristics are caused.
In addition, if the amount of the positive and negative electrodes is reduced, the positive and negative
The current collecting ability of each of the negative electrodes decreases, leading to a decrease in high-rate discharge characteristics, low-temperature discharge characteristics, and the like. Furthermore, the volume occupied by the separator can be reduced by reducing the thickness of the separator.However, when the battery is formed in a spiral shape, the internal short circuit of the battery due to burrs caused by cutting and breaking of the positive and negative electrodes increases, resulting in increased production. Is reduced. Further, a mere reduction in thickness of the separator leads to a decrease in the ability to retain the electrolytic solution, resulting in a decrease in battery characteristics such as discharge characteristics and life characteristics.

[0009] The present invention provides a discharge characteristic,
It solves productivity issues when creating batteries.
Even if the volume occupied by the positive electrode active material is increased to further increase the capacity and improve the energy density per unit volume, it has discharge characteristics equal to or better than that of conventional batteries, and the occurrence of internal short-circuit failure during battery construction The main object of the present invention is to provide a highly productive alkaline storage battery that suppresses as much as possible.

[0010]

SUMMARY OF THE INVENTION In order to solve these problems, the present invention relates to a method of manufacturing a magnetic recording medium, comprising:
A positive electrode plate having a structure in which one surface is arranged 1.1 times or more larger than the other surface in the active material weight, and one in the thickness of the active material in the thickness direction of the electrode plate with respect to the plate-shaped conductive core material A negative electrode plate having a structure in which the surfaces are arranged 1.1 times or more larger than the other surface is spirally wound with the surfaces having a large active material weight and the surfaces having a low active material weight opposed to each other via a separator. Turned and stored in the battery case. Then, preferably, the negative electrode is spirally wound so that the surface with the lower active material weight is on the outer peripheral surface side, and the electrolyte retaining amount of the separator portion between the surfaces with the higher active material weight is reduced with the lower active material weight. The present invention provides an alkaline storage battery characterized in that the amount of electrolyte retained in a separator portion between the surfaces is 1.1 times or more.

As a result, even when the volume occupied by the positive electrode active material is increased to further increase the capacity and improve the energy density per unit volume, the battery has a discharge characteristic equal to or higher than that of a conventional battery, It is possible to provide an alkaline storage battery with high productivity in which occurrence of internal short circuit failure is suppressed as much as possible.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION According to the first aspect of the present invention, one side of the active material is 1.1 times or more the weight of the active material at the center of the electrode plate in the thickness direction. A positive electrode plate having a structure in which many are arranged, and a structure in which one surface is arranged to be 1.1 times or more larger than the other surface in an active material weight in a thickness direction of the electrode plate with a plate-shaped conductive core as a boundary. A negative electrode plate having a surface with a high active material weight and a surface with a low active material weight facing each other via a separator and spirally wound and housed in a battery case. And the discharge reaction can be efficiently advanced by opposing them uniformly. In addition, since the surface of the positive and negative electrodes with a large active material weight has a relatively higher packing density than the surface of a small active material weight, a discharge reaction such as contact resistance between active material powders in an electrode is alienated. Since the resistance of the discharge reaction can be eliminated, the discharge reaction can proceed efficiently.

According to a second aspect of the present invention, when the length of the electrode plate is constant, the negative electrode is spirally wound and housed in the battery case such that the surface of the negative electrode having a large active material weight is on the outer peripheral surface side. Since the weight of the positive electrode and the negative electrode active material opposed to the counter electrode can be increased as compared with the case of the above, the discharge reaction characteristics are improved.

According to the third aspect of the present invention, since the amount of the electrolyte on the opposite surface between the surfaces having a large active material weight, which are the main reaction sites, can be increased, the discharge reaction characteristics can be improved.

According to the fourth aspect of the present invention, it is possible to prevent the most internal short-circuit of the battery when the battery is formed in a spiral shape, which is caused by burrs or the like due to the most bent outer peripheral surface of the positive electrode.

According to the fifth aspect of the present invention, as in the third aspect of the present invention, since the amount of the electrolyte between the opposing surfaces having a large weight of the active material, which is the main reaction field, can be increased, the discharge can be increased. The reaction characteristics can be improved.

According to a sixth aspect of the present invention, the conductivity and the current collecting property of the core can be improved more than a punching metal or the like obtained by plating nickel on iron, which has been conventionally used as a conductive core of the negative electrode. As a result, the discharge reaction characteristics can be improved and the cost can be reduced.

In the invention according to claim 7, the weight of the active material per unit volume of the positive electrode can be increased and the capacity can be increased by using the foamed metal porous body. Further, by using the nickel-coated foamed iron, cost reduction can be achieved.

The invention according to claim 8 defines an uneven distribution state of the active material filling amounts of the positive electrode and the negative electrode. If the uneven distribution state exceeds twice, the electrode surface side with a large amount of active material filling becomes
As the porosity decreases, the amount of the electrolytic solution decreases, and the discharge reaction does not proceed smoothly, so that the discharge characteristics deteriorate. In the case of a negative electrode, the distance between the active material on the electrode surface and the conductive core material is further increased, and the current collecting ability is further reduced, which further causes a reduction in the discharge characteristics.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. (Embodiment) FIG. 1 is a schematic view of a stacked electrode group before being spirally wound. In the figure, 1 is a positive electrode plate, 2 is a negative electrode plate,
Reference numerals 3 and 4 denote separators. In the positive electrode plate 1, the portion 1a has a larger active material weight than the portion 1b at the center of the thickness direction of the electrode plate indicated by the dotted line as a boundary. With this configuration, the paste viscosity is sufficiently increased when the paste-like active material is filled in a porous metal body that is a support for the positive electrode active material, and
This can be achieved by filling the paste only from the side a and making the electrode plate such that the active material paste does not easily come off to the outer surface of the area 1b. Further, the porosity of the porous metal body may be changed in the thickness direction. In the negative electrode plate 2, the portion 2 a is 2 b with the conductive core material 5 as a boundary.
The active material weight is larger than that of the portion. This configuration can be created by controlling the amount of application on the 2a surface and 2b surface when applying the paste active material to the conductive core material 5. In the positive electrode plate 1 and the negative electrode plate 2, surfaces 1 a and 2 a, which are large in active material weight, are opposed to each other with a separator 3 interposed therebetween. The separators 3 and 4 may be the same, but the separator 4 may be thinner than the separator 3 when increasing the capacity of the battery. Further, in order to improve battery characteristics such as discharge characteristics, the electrolyte retention capacity of the separator 3 may be higher than that of the separator 4. Further, as the material of the separator, an olefin-based microporous film may be used in addition to the olefin-based nonwoven fabric conventionally used. In particular, when the thickness of the separator 4 is reduced to about 50 μm, which is about 1/3 to 1/4 of that of the conventional separator, a film-like polypropylene or polyethylene or the like is subjected to a sulfonation treatment or the like from the viewpoint of uniformity of liquid retention. Those subjected to a hydrophilic treatment are preferred.

FIG. 2A is a sectional view in which the stacked electrode group of FIG. 1 is spirally wound and housed in a battery case 6. In the figure, 7 is a positive electrode terminal cap, 8 is a safety valve, 9 is a sealing plate, 1
0 is an insulating gasket. In this state, the negative electrode plate 2
As shown in an enlarged manner in FIG.
The battery case 6 is housed in such a manner that the surface b is the outermost peripheral surface side and is in contact with the inner wall of the battery case 6.

[0022]

Next, a specific example of the present invention will be described with reference to a nickel-hydrogen storage battery using nickel hydroxide as a positive electrode active material and a hydrogen storage alloy as a negative electrode active material.

(Example 1) A positive electrode was prepared in the following procedure. First, 7 parts by weight of a cobalt hydroxide powder and 3 parts by weight of a cobalt oxide powder were mixed with 100 parts by weight of a spherical nickel hydroxide powder having an average particle diameter of 10 μm as an active material, and water was added thereto. A 20% by weight paste was made. After filling this paste into the sponge-like nickel porous body from the 1a side of FIG. 1, drying, pressing, and cutting,
Length 80mm, height 36.5mm, thickness 1.2mm,
An electrode plate having a theoretical capacity of 2250 mAh was prepared. At this time,
The filling capacity density of the positive electrode was 650 mAh / cc. When the weight of the active material in the thickness direction of the positive electrode plate was measured as shown in FIG. 1, about 4.4 g (730 mAh / c
c) The side 1b was about 3.4 g (560 mAh / cc), and the side 1a had a smaller porosity than the side 1b, and the packing density was 1.3 times higher.

Next, a hydrogen storage alloy for electrochemically storing and releasing hydrogen as an active material and a negative electrode using the same were prepared by the following method.

A misch metal (hereinafter, referred to as Mm) mainly containing about 40% by weight of cerium, about 30% by weight of lanthanum, and about 13% by weight of neodymium, nickel, cobalt, aluminum and manganese in an atomic ratio of 1: 3. 5
5: 0.75: 0.3: 0.4
This was melted in a high-frequency melting furnace to prepare a hydrogen absorbing alloy of MmNi _3.55 Mn _0.4 Al _0.3 Co _0.75 having a CaCu ₅ type crystal structure. This hydrogen storage alloy was heat-treated in vacuum at 1050 ° C. for 6 hours to homogenize the sample, and then mechanically pulverized to 54 μm or less to obtain a fine powder having an average particle diameter of 30 μm. The theoretical capacity of this alloy is 2
It was 90 mAh / g.

The hydrogen-absorbing alloy powder obtained as described above is stirred in a KOH solution at 80 ° C., washed with water,
A dispersion of styrene-butadiene rubber, carboxymethylcellulose, carbon and water are mixed to form a paste, which is coated on a punching metal as a conductive core material 5 having a 50% open hole ratio and a 50 μm-thick nickel-plated iron, After drying, pressing and cutting, length 120mm, height 3
An electrode plate having a capacity of 3,400 mAh and a thickness of 6.5 mm, a thickness of 0.50 mm was prepared. At this time, the negative electrode had a porosity of about 15% as an electrode plate, and the filling capacity density was about 1550 mAh / cc. Further, when the weight of the active material in the thickness direction of the negative electrode plate was measured, about 6.6 g (1920 mAh)
Side is about 5.1 g (1480 mAh) and 2a side is 2
It was about 1.3 times the b-side.

Next, as shown in FIG. 1, the electrode surfaces having a large amount of active material are laminated so as to face each other, and the above-mentioned paste-type positive electrode and negative electrode are spirally wound via a separator in the manner shown in FIG. 2A. Turned. In this state, the electrode surface 2b of the negative electrode with a small amount of the active material was in contact with the metal case 6 also serving as a current collector. At this time, a non-woven fabric made of sulfonated polypropylene was used as the separator, and the separator 3 in FIG. 1 had a basis weight of 65 g / m ² , a length of 130 mm, and a height of 3
The separator 4 had a weight of 45 g / m ² , a length of 100 mm, a height of 38 mm, and a thickness of 0.08 mm. This electrode group was inserted into the battery case 6 to form a 4/5 A sealed battery having a capacity of 2250 mAh. As the electrolyte, a solution prepared by dissolving 40 g / l of LiOH.H ₂ O in a KOH aqueous solution having a specific gravity of 1.30 was used, and 2.3 cc was injected per cell to prepare a battery A. The nominal capacity of this battery A is 2200 mAh.

Also, using the electrode of the battery A, contrary to FIG. 1, the electrode surfaces with a small amount of active material filling (1b surface and 2b surface) were used.
The battery was constructed by spirally winding the laminate on the inner peripheral surface side. This was designated as Battery B. In this state, the electrode surface 2a of the negative electrode having a large amount of the active material was in contact with the metal case 6 also serving as a current collector.

Next, as comparative batteries, the following batteries C and D were used.
Was prepared. The positive electrode whose active material weight on both the 1a side and 1b side was about 3.9 g (1125 mAh / cc), the active material weight on both the 2a side and 2b side was about 5.9 g (1700 m
A comparative battery C was prepared in the same manner as the battery A, except that each of the negative electrodes Ah) was used.

Further, the same positive electrode plate 1 and negative electrode plate 2 as the battery A are used.
1 is different from FIG. 1 in that the comparative battery D is the same as the battery A except that the 1a surface of the positive electrode having a large active material weight and the 2b surface of the negative electrode having a small active material weight are opposed to each other via the separator 3. It was created.

After charging the above four types of batteries A to D at a current value of 1 A (0.45 C) for 3 hours in an environment of 20 ° C.,
The discharge was performed at various current values of 0 mA (0.2 C) to 10 A (4.5 C) to a final voltage of 1.0 V, and the high rate discharge characteristics were evaluated. FIG. 3 shows a comparison of the ratio of the discharge capacity to the theoretical capacity. As is clear from FIG. 3, the batteries A and B, which are the examples of the present invention, had better discharge characteristics than the batteries C and D of the comparative examples. In particular, the tendency was remarkable as the discharge current value increased. Then, the battery is configured such that the battery C is larger than the battery D, the batteries A and B are larger than the battery C, and the electrode plate surfaces (1a surface and 2a surface) having a larger amount of the active material of the positive electrode and the negative electrode are opposed to each other. It was also found that good discharge characteristics were obtained even when the discharge current value was large. Although various reasons may be considered, it is presumed that the reaction resistance could be considerably reduced by shortening the physical distance between the positive and negative active materials, which are reactive species. Further, the surfaces of the positive and negative electrodes with a large active material weight (1a surface and 2a surface) have a relatively higher packing density than the surfaces with a small active material weight (1b surface and 2b surface). It is presumed that the discharge reaction, such as contact resistance between the active material powders, can be eliminated, so that the discharge reaction could be efficiently advanced.

Although the difference in characteristics between Battery A and Battery B was small, Battery A showed slightly better results. The reason was presumed as follows. In these batteries, the electrode plates are spirally wound substantially three times, and in the case of battery B, the negative electrode surface having the large amount of active material at the outermost periphery of the group does not face the positive electrode. Therefore, it was presumed that the battery B had a smaller amount of active material involved in discharging than the battery A, and had deteriorated characteristics.

(Example 2) Next, it was examined how the uneven distribution state of the active material filling amounts of the positive electrode and the negative electrode and the facing conditions of the respective electrodes affect the discharge characteristics. The test conditions were the same as in Example 1.

FIG. 4 shows discharge characteristics at 5A (corresponding to 2.2C) and 10A (corresponding to 4.5C) when the same positive electrode as in Example 1 is used and negative electrodes having different active material filling amounts are combined. The result was shown. In FIG. 5, 5A (corresponding to 2.2C) and 10A (4.
(Corresponding to 5 C).

From the results shown in FIGS. 4 and 5, the battery C of Comparative Example 2 was obtained.
As can be seen from the results, simply distributing the active material filling amount of the positive electrode or the negative electrode cannot obtain good discharge characteristics, and the two electrodes (1a) having the active material filling amount unevenly distributed cannot be obtained.
It has been clarified that it is important to make the surface and the 2a surface) well opposed. Then, as the uneven distribution state of the active material filling amount, both the positive electrode and the negative electrode may be unevenly distributed 1.1 times or more,
In addition, electrode surfaces with a large amount of active material filling (1a surface and 2
It has been found that it is necessary to make the (a surface) oppose. Furthermore, from the results of Example 1, it is preferable that the electrode surface 2b of the negative electrode having a small amount of active material is spirally wound so that the surface of the electrode surface 2b is in contact with the metal case 6 also serving as a current collector.

However, if the unevenly distributed state of the active material loading of the positive electrode and the negative electrode exceeds twice, the electrode surface side with a large active material loading will decrease in the amount of electrolyte due to the decrease in porosity, and the discharge reaction Does not proceed smoothly, causing a decrease in discharge characteristics. In addition, in the case of a negative electrode, the distance between the active material on the electrode surface and the conductive core material is further increased, and the current collecting ability is further reduced. For this reason, as for the positive electrode and the negative electrode, the uneven distribution state of the active material filling amount is preferably 1.1 to 2 times.

Example 3 Next, the physical properties of the separator were examined. Four types of batteries E to H were prepared using polypropylene nonwoven fabrics having various electrolyte retention properties, thicknesses, and space volumes as separators 3 and 4 of battery A, and a discharge test was performed in the same manner as in Example 1. Was done. The electrolyte retention characteristics of the separator were controlled by changing the basis weight and the treatment ratio of the sulfonation treatment, and the space volume was controlled by changing the thickness and the basis weight. The space volume was calculated on the assumption that the specific gravity of polypropylene was 0.91 g / cc.

Table 1 shows the physical properties of the separators 3 and 4 of the batteries A and E to H, and 5A (2.2C) at that time.
The results of the discharge characteristics at 10 A (equivalent to 4.5 C) were shown.

[0039]

[Table 1] The electrolyte retention amount ratio in Table 1 is the ratio of the electrolyte retention amount of the separator 3 to the electrolyte retention amount of the separator 4, and the liquid retention amount is the weight before and after the separator is immersed in the electrolyte for 30 minutes or more. Determined by change.

From the results in Table 1, it can be seen that the ratio of the amount of retained liquid, that is, the ratio of the amount of retained electrolyte in the separator 3 to the amount of retained electrolyte in the separator 4 is small, and the distance between the electrode surfaces having a large amount of active material is reduced. When the amount of retained electrolyte of the electrolyte decreases, large current discharge,
In particular, it was found that the high-rate discharge characteristics of 10 A decreased. This is because both electrodes (1a surface and 2a surface) in which the active material filling amount is unevenly distributed in order to allow the electrode reaction to proceed smoothly.
Means that it is necessary to allow a large amount of electrolyte to be present between the two electrodes on which the active material is unevenly distributed. From the above results, it is preferable that the separator 3 is 1.1 times or more larger than the separator 4 as the electrolyte solution holding amount ratio. Further, the space volume of the separator is also closely related to the amount of retained electrolyte. For this reason, if the space volume of the separator 3 is 1.1 times or more larger than that of the separator 4, even if two types of separators are formed under the same basis weight and hydrophilic treatment conditions, a large amount of active material is unevenly distributed between the two electrodes. This is effective because the electrolyte solution can be held. Further, the thickness of the separator does not directly affect the battery characteristics. However, in general, when the battery is spirally wound on the outer peripheral side of the positive electrode, burrs or the like are generated due to breakage of the electrode plate,
Internal short circuit failure easily occurs in battery configuration. for that reason,
When the separator 3 is located on the outer peripheral side of the positive electrode as in the case of the battery A, the thickness of the separator 3 is 1.
It is preferable that the thickness is at least one time.

Example 4 Next, the material of the negative electrode core material was examined.

A battery I was prepared in the same manner as the battery A, except that the same thickness of electrolytic copper foil was used for the negative electrode core material 5, and a discharge test was performed in the same manner as in Example 1 to compare. . As a result, the discharge capacity ratio of 10A was 74%, which was better than that of Battery A. This is presumed to be because the electric resistance of copper is about 1/6 of the electric resistance of iron, which is the main component of the punching metal. In addition, copper foil having a thickness of about 10 to 40 μm is widely used for applications such as printed circuit boards and capacitors, and can be omitted because a process such as drilling a steel plate like a panning metal can be omitted. Inexpensive and preferred.

Regarding the porous metal as the support for the positive electrode, conventionally used foamed nickel is preferable from the viewpoint of increasing the capacity density of the positive electrode and from the versatility. Also,
Iron may be used instead of nickel in order to create a more inexpensive electrode plate. In that case, however, plating is performed on the foamed iron surface because it is stably present during charging and discharging in an alkaline electrolyte. It is preferable to coat with nickel or the like.

As described above, even when the volume occupied by the positive electrode active material is increased to further increase the capacity and improve the energy density per unit volume, the battery has a discharge characteristic equal to or higher than that of a conventional battery. In addition, it is possible to provide an alkaline storage battery with high productivity in which occurrence of internal short-circuit failure in a battery configuration is suppressed as much as possible.

It is needless to say that the same effect can be observed in the present invention in other alkaline storage batteries having different positive and negative electrode active materials, such as nickel-zinc storage batteries and manganese dioxide-hydrogen storage batteries other than nickel-hydrogen storage batteries. .

[0046]

As described above, according to the present invention, one surface is arranged at least 1.1 times as large as the other surface in terms of the weight of the active material from the center in the thickness direction of the electrode plate. Plate having a structure in which one surface is disposed at least 1.1 times as large as the other surface in the thickness of the active material in the thickness direction of the electrode plate with respect to the plate-shaped conductive core material. The cathode active material and the anode active material are evenly distributed by spirally winding the surfaces having a large active material weight and the surfaces having a small active material weight facing each other via a separator and storing them in a battery case. In this case, the charge-discharge reaction can proceed efficiently, and the effect of providing an alkaline storage battery having excellent discharge characteristics can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a stack of electrodes according to an embodiment of the present invention.

2A is a cross-sectional view in which the electrode group of FIG. 1 is spirally wound and accommodated in a battery case. FIG. 2B is an enlarged cross-sectional view of the electrode group.

FIG. 3 is a diagram showing a relationship between a discharge current value and a ratio of a discharge capacity to a theoretical capacity.

FIG. 4 is a diagram showing the relationship between the uneven distribution state of a negative electrode active material and discharge characteristics.

FIG. 5 is a diagram showing the relationship between the uneven distribution state of a positive electrode active material and discharge characteristics.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Positive electrode 1a Positive electrode surface 1b Positive electrode surface 2 Negative electrode 2a Negative electrode surface 2b Negative electrode surface 3 Separator 4 Separator 5 Negative conductive core material 6 Battery case 7 Cap 8 Safety valve 9 Sealing plate 10 Insulating gasket

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-52-116839 (JP, A) JP-A-9-27342 (JP, A) JP-A-4-12471 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H01M 10/04 H01M 10/24-10/34 H01M 4/24-4/34

Claims (8)

(57) [Claims] 1. A positive electrode in which a constituent material mainly composed of a metal oxide is held in a porous metal body having a three-dimensionally continuous space, and a constituent material mainly composed of an active material is pressed to a conductive core material. An alkaline storage battery including a negative electrode, a separator, and an alkaline electrolyte, wherein one surface is 1.1 times or more in weight of the active material as compared with the other surface with respect to a center portion in a thickness direction of the electrode plate. A positive electrode plate having a disposed structure, and a structure in which one surface is disposed at least 1.1 times greater than the other surface in the thickness of the active material in the thickness direction of the electrode plate with respect to the plate-shaped conductive core material An alkaline storage battery comprising: a negative electrode plate having a surface with a large active material weight and a surface with a small active material weight opposed to each other with a separator interposed therebetween; 2. A surface having a high active material weight and a surface having a low active material weight are opposed to each other via a separator,
The alkaline storage battery according to claim 1, wherein the negative electrode is spirally wound and housed in a battery case such that a surface of the negative electrode having a small active material weight is on an outer peripheral surface side. 3. The amount of electrolyte retained in a separator portion between surfaces having a large active material weight is 1.1 times or more the amount of electrolyte solution retained in a separator portion between surfaces having a small active material weight. 3. The alkaline storage battery according to claim 1, wherein the amount is large. 4. The separator according to claim 1, wherein the thickness of the separator between the surfaces having a large active material weight is at least 1.1 times greater than the thickness of the separator between the surfaces having a small active material weight. Alkaline storage batteries. 5. The separator according to claim 1, wherein the spatial volume of the separator between the surfaces having a large active material weight is at least 1.1 times larger than the spatial volume of the separator between the surfaces having a small active material weight. 3. The alkaline storage battery according to 1 or 2. 6. The alkaline storage battery according to claim 1, wherein the conductive core material of the negative electrode is a copper foil. 7. The alkaline storage battery according to claim 1, wherein the porous metal body of the positive electrode is foamed nickel or foamed iron coated with nickel. 8. A positive electrode in which a constituent material mainly composed of a metal oxide is held in a porous metal body having a three-dimensionally continuous space, and a constituent material mainly composed of an active material is pressed to a conductive core material. An alkaline storage battery including an electrode group in which a negative electrode is spirally wound with a separator interposed therebetween, and an alkaline electrolyte, wherein one surface is the other in terms of active material weight with respect to the center in the thickness direction of the electrode plate. And a positive electrode plate having a structure arranged 1.1 to 2 times more than the surface, and one surface of the positive electrode plate is 1% smaller than the other surface in the active material weight in the thickness direction of the electrode plate with respect to the plate-shaped conductive core. An alkaline storage battery in which a surface having a large weight of active material is opposed to a negative electrode plate having a structure arranged one to two times more via a separator.