JP3093801B2 - Battery manufacturing method and battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery separator material.
The present invention relates to a battery manufacturing method and a battery including:

[0002]

2. Description of the Related Art Materials such as felt made of glass fiber, cellulose-based paper, and nonwoven fabric made of polypropylene are used for battery separators. These materials are originally porous and have properties unique to a separator, such as liquid permeability, gas permeability, and liquid retention, and are cut to fit the shape of the battery and used as a battery separator.

For example, in a sealed lead-acid battery, a mat-shaped separator having an improved separator strength is used, which is effective in liberating the installation direction of the battery, ensuring liquid retention, and maintaining the strength of the separator. Has been demonstrated. This has a structure in which particles of an inorganic substance such as alumina are carried inside a glass fiber felt.

Further, when a battery is manufactured by a spiral electrode winding method using a sheet-shaped separator material, compression deformation and tearing of the separator when winding the electrode, generation of the electrode, In order to prevent the occurrence of compression deformation or tearing of the separator due to expansion due to charge and discharge of the separator, and to prevent an increase in internal resistance and an occurrence of an internal short circuit due to a decrease in the amount of retained liquid accompanying the separator, for example, a method described in JP-A-2-213047 is disclosed. It has been considered to use a separator material having a high electrolytic solution holding capacity in which a titanium oxide having a specific primary particle diameter, crystal form and specific surface area is contained in a separator base made of a nonwoven fabric or the like as described above.

On the other hand, in a secondary battery in which a hydrogen storage alloy is used for a negative electrode, the hydrogen storage alloy is pulverized due to a change in volume of the negative electrode hydrogen storage alloy during a charge / discharge cycle. From the battery and poor current collection, leading to deterioration of battery characteristics. As a method of solving this problem, a method of forming a battery by heat-sealing a negative electrode made of a hydrogen storage alloy to a heat-fusible resin sheet and facing the hydrogen storage alloy side of the two-layer structure negative electrode to the separator. Alternatively, a hydrogen storage alloy and a heat-fusible resin are mixed to form a negative electrode,
There is a method for forming a battery using the separator.

[0006]

Some conventional separator materials have poor electrophilicity. Especially when a felt made of glass fiber or a nonwoven fabric made of polypropylene is used, these materials are hardly compatible with the electrolyte. In order to make the battery operate well, it is necessary to give the lyophilic property by a treatment such as boiling in the electrolyte or a treatment with a surfactant.
Had to be used as a separator. For this reason, an extra step for imparting electrolyte affinity is required,
Furthermore, since this step needs to be performed, the electrodes and the separator must be assembled in a state where the electrolytic solution is interposed, and there is a disadvantage that each process line of the assembly is wet and exposed to the electrolytic solution. In addition, a battery using the separator has a problem in that the effect of the treatment for imparting electrolyte affinity is weakened during repeated charging and discharging, thereby reducing the battery capacity.

Further, in the case of a conventional battery using a hydrogen storage alloy, it is difficult to make electrical contact between the container and the electrode in a negative electrode using a heat-fusible sheet. The negative electrode manufactured by the method has a problem that the capacity density per volume is reduced, and a new structure for preventing the characteristic deterioration due to the pulverization of the hydrogen storage alloy has been desired.

[0008]

The present invention also aims to provide a cell with a less deformation separator material in the thickness direction with respect to compressive stresses.

It is a further object of the present invention to provide a battery which does not cause a decrease in battery capacity due to a decrease in electrolyte affinity of the separator even after repeated charging and discharging.

Another object of the present invention is to provide a battery using a hydrogen storage alloy for a negative electrode, which has a large capacity density without deterioration in characteristics due to pulverization of the hydrogen storage alloy.

[0012]

A method for manufacturing a battery according to the present invention solves the above-mentioned problems, and comprises a polymer material which is insoluble in a predetermined electrolytic solution and a polymer material which is insoluble in the electrolytic solution. to a mixture of soluble material having, in the electrolyte
In a separator material obtained by dispersing an inorganic powder that does not dissolve , in a battery container, a positive electrode, a negative electrode, and in a state where the separator material is provided, by supplying the electrolytic solution,
A method for producing a battery, characterized in that the soluble material is eluted from the separator material into the electrolytic solution in the battery container. Further, the inorganic powder has a particle diameter of 10 to 100 μm.

[0013] In the above method for producing a battery,
The polymer material has a polar group.

Further , in the above method for producing a battery,
The negative electrode is made of a hydrogen storage alloy, and
With the alloy and the separator material bonded together,
It is characterized by supplying a lysate.

A battery according to the present invention is a battery manufactured by
It is manufactured by a manufacturing method.

The separator material of the present invention is formed, for example, by mixing a non-soluble polymer material, a soluble material, and an inorganic powder at a predetermined ratio to form a molded body using the non-soluble polymer material as a skeleton. It is manufactured by To make a molded body,
High frequency heat fusion, laser heat fusion, ultrasonic fusion,
A pressure welding method or the like, a spin casting method, a spray casting method, or the like can be used. For example, a powder of a heat-fusible non-soluble polymer material and a powder of a soluble material are mixed, and molded while applying heat thereto. 3 of soluble polymer material powder
A separator material having the dimensional combination as a skeleton is formed.

For molding, a molding die device shown in the schematic configuration diagram of FIG. 14 or a roll molding device shown in a schematic configuration diagram of FIG. 15 can be used. The molding die apparatus of FIG. 14 includes a molding die 11, an upper punch 13, and a lower punch 14, and a heater 12 is charged in the molding die 11. It should be noted that instead of the heating by the charged heater 12, heating by a hot plate or the like may be performed. The roll forming apparatus shown in FIG. 15 includes two rolls 17 and 18.
The mixed material 16 is introduced into the slight gap between the 18 and
It is formed into a film by rolling. At this time, roll 1
By heating at least one of 7 and 18, the heat-fusible insoluble polymer material powder is fused. If the powder of the insoluble polymer material is press-bondable, it can be molded without heating.

[0018] In addition, it is possible to similarly form by fusion using an ultrasonic fusion device shown in the schematic configuration diagram of FIG. The present apparatus utilizes a phenomenon in which particles of powder are thermally fused to each other due to friction between the particles of the powder due to vibration by ultrasonic waves. The ultrasonic welding apparatus shown in FIG. 16 includes a vibrator 19, a booster horn 20, a horn 21, and a pedestal 22, and the ultrasonic vibration by the horn 21 is amplified by the booster horn 20. This ultrasonic vibration is transmitted from above to the mixture on the pedestal 22 pressed by the vibrator 19, and the powder of the insoluble polymer material having heat-fusibility is fused to form a separator material.

Further, at least one of the insoluble polymer material and the soluble material is dissolved in a specific solvent to disperse the inorganic powder, and the spin casting method shown in FIG. 17 and the spin casting method shown in FIG. It can be formed into a film using the spray casting method shown below. In this case, it is preferable to dissolve at least the insoluble polymer material. In this method, the solvent is evaporated to form a film-like molded body composed of a film-like insoluble polymer material skeleton. Note that FIG.
In the spin casting method of the above, 24 is a spin coater, 23
Is a liquid supply device in which a solution 27 in which an inorganic powder is dispersed in a mixed solution or a dispersion solution of a non-soluble polymer material and a soluble material is filled. In the spray casting method of FIG. 18, 25 is a tank in which the same solution 27 is put, 26 is a stirring rod, 28 is a liquid supply pump, 29 is a nozzle,
Reference numeral 31 denotes a developing table, and reference numeral 30 denotes a molded film obtained by the present apparatus.

Examples of materials used for the separator material of the present invention include the following. Insoluble polymer materials include heat-fusible polyethylene, polypropylene,
Polytetrafluoroethylene and various substituted products thereof are used. Of these, modified polyolefins such as polyethylene, polypropylene, ethylene-propylene copolymers and ionomers having polar groups introduced, and polytetrafluoroethylene and the like have high insolubility. Preferably with good adhesion between molecular materials and with inorganic powder, especially,
Modified polyolefins having maleic anhydride as a substituent are preferred because of their high adhesive strength. On the other hand, examples of insoluble polymer materials that can be dissolved into a solution or a paste form include nitrocellulose, acrylonitrile, and styrene-based resins that dissolve in a non-aqueous solvent and do not dissolve in an aqueous solution when used in an aqueous electrolyte solution. When used in a non-aqueous electrolyte, there are polyethylene glycol, polyvinyl alcohol, cellulose derivatives, and the like in reverse.

Examples of the soluble material include polymers such as carboxymethylcellulose, sodium carboxymethylcellulose, and cellulose derivatives such as methylcellulose, agar, starch, and polyvinyl alcohol. Other organic substances include adipic acid, stearic acid, and glutamic acid. And its salts. As the inorganic substance, in the case of an aqueous electrolyte, a basic oxide such as Li ₂ O, Na ₂ O, or K ₂ O or a basic hydroxide such as LiOH, NaOH, or KOH is used. In the case of a non-aqueous electrolyte, Is LiClO ₄ , Li
BF ₄ And so on.

The mixing ratio between the insoluble polymer material and the soluble material can be changed within the range of 10 to 90% for the former and 90 to 10% for the latter, but is preferably 20 to 60%, respectively.
%, And 80 to 40%. This ratio greatly affects the properties of the separator to be formed, and the appropriate value greatly changes depending on the material used for each, particularly the former.

Examples of the inorganic powder include inorganic beads such as glass beads, alumina beads, and silica beads, and white alumina and carborundum used for abrasives. In the use of these inorganic powders, a base polymer composed of a mixture of a non-soluble polymer material and a soluble material to be dispersed and supported is generally formed into a thin sheet. In particular, it is preferable to use one having a particle size of 10 to 100 μm. Also,
When mixing, it is preferable to use a material having a particle size distribution within the range of the particle size rather than using the same particle size for maintaining the adhesive strength of the base polymer, and to use a larger amount of inorganic powder. It is possible to mix them, thereby increasing the resistance of the separator made of the base polymer to the compressive stress, and ensuring the liquid retention amount by maintaining the porosity. The amount of the inorganic powder mixed is 10 to 4 with respect to 100 parts by weight of the insoluble polymer material in the base polymer.
0 parts by weight is preferred. This is because if the mixing amount is less than the above range, the resistance to the compressive stress of the separator is significantly reduced, and if the mixing amount is more than the above range, the soluble material is dissolved by the electrolytic solution, and the remaining separator made of the insoluble polymer material is left. This is because the mechanical strength of the rubber composition decreases.

It is preferable to use inorganic beads as the powder. The inorganic beads have a shape close to a perfect sphere and are well dispersed in the base polymer.For example, even when formed into a thin film-like separator material having a thickness of about 30 μm, the inorganic beads are uniformly dispersed. This is because the adhesive force between the powders of the insoluble polymer material is less likely to be locally reduced.

[0025]

When the separator material used in the present invention is immersed in a predetermined electrolytic solution, a soluble material is eluted in the electrolytic solution to form a porous body composed of a non-soluble polymer skeleton. Thus, the structure is suitable for a battery separator. The porosity of this porous body is easily controlled by the mixing ratio between the insoluble polymer material and the soluble material. At the same time, by the action of the soluble material, the surface of the obtained porous body is given an electrophilicity. Therefore, if the battery separator material of the present invention is made of a material suitable for the electrolyte solution of the battery to be assembled, the battery can be assembled using this separator material in the same manner as a normal separator, and the electrolyte supply during the process can be performed. In the process, the soluble material elutes and acts as a normal separator. Then, after all the components such as the electrodes and the separator material have been incorporated into the battery container, if the electrolysis night is injected for the first time in the final process, the assembly process can be performed in a dry manner .

The lyophilic property imparted to the porous body obtained from the battery separator material of the present invention is not lost during use as a battery, and the soluble material is replaced with a suitable polymer or inorganic material. By using (for example, LiOH in the case of an alkaline secondary battery), the charge / discharge cycle life of the battery and the utilization rate of the electrode active material can be improved. Further
In addition, a component corresponding to the electrolyte of the electrolytic solution is used for the soluble material.
Is also effective. Therefore, a battery having a separator obtained from the separator material of the present invention has excellent battery characteristics such as cycle characteristics and capacity density.

Further, by dispersing the inorganic powder in the separator material, resistance to deformation in the thickness direction due to compressive stress of the separator can be increased. Therefore, the liquid retention amount can be secured by maintaining the porosity, and an increase in internal resistance can be suppressed. On the other hand, by improving the resistance to compressive stress, internal short circuit due to dielectric breakdown of the separator,
As a result, heat and ignition of the battery due to rapid abnormal discharge can be prevented.

In a battery in which a hydrogen storage alloy serving as a negative electrode active material is bound to a separator obtained from the separator material of the present invention, the separator is bound to the negative electrode active material to prevent pulverization due to charge and discharge. In addition, the internal shortening due to the collapse and falling off of the negative electrode is prevented, and the charge / discharge cycle characteristics are improved. The method for manufacturing a battery according to the present invention is performed by fusing to the separator material,
After the negative electrode is integrated by a method such as pressure bonding, it is assembled in combination with the positive electrode, and the soluble material of the separator material elutes into the electrolytic solution due to the electrolyte supply process during the assembly process, and the negative electrode and the porous body And a battery having a structure integrated with the separator. The integration of the negative electrode and the separator material may be performed at the same time as the molding of the separator material or may be performed after the molding, and the same method as in the molding of the separator material can be used.

[0029]

【Example】

Embodiment 1 An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a view for explaining a process of assembling a battery of the present invention, wherein 1 is an electrolytic solution, 2 is a negative electrode, 3 is a separator material, 3 ′ is a separator, 4 is a positive electrode can, and 5 is a battery for sealing a battery container. A gasket, 6 is a positive electrode, 7A and 7B are current collectors, 8 is a negative electrode cover, and 9 is a hole.

First, 10 parts by weight of heat-fusible polyethylene, which is a material of the separator material of the present invention, and 5 parts by weight of sodium carboxymethylcellulose are mixed. next,
After dispensing 60 mg of the mixed separator material, it is put into the molding die 11 of the molding die apparatus shown in FIG. 14 and pressed at 120 ° C. and 100 kgw / cm ² for about 30 seconds. A separator material according to the invention was prepared.
At this time, a molding die 11 having an inner diameter of 20 mm was used.

Next, TiNi, which is the material of the negative electrode, is charged into a pressure-resistant container (not shown), and the temperature is raised to 300 ° C.
Absorb and release gaseous hydrogen at atmospheric pressure, 0.1 Torr
The mixture was gradually cooled to 25 ° C. while being degassed. Then 2
Store gaseous hydrogen overnight at 5 ° C. and 1 atmosphere,
The TiNi2g a hydrogen-absorbing alloy was placed in mold 11 of Figure 1 4 (inner diameter 18 mm), followed by, 18 mm
A Ni wire net having a wire diameter of 0.1 mm and a mesh of 100 mesh punched into an outer diameter of 100 mm was charged, and press-molded at 700 kgw / cm ² from above to be taken out to prepare a negative electrode. At this time, the negative electrode capacity was 150 mAh. Next, a chemical conversion treatment is performed electrochemically in an alkaline aqueous solution such as an aqueous potassium hydroxide solution to produce a sintered nickel electrode (18 mm in outer diameter) having a capacity of 100 mAh and cut into a predetermined size. To prepare a positive electrode.

The negative electrode 2 and the positive electrode 6 manufactured as described above are combined with each other in such a manner that the separator material 3 is sandwiched, placed in the positive electrode can 4 covered with the current collector 7A, and supplied with the electrolytic solution 1. 1 (a)). The electrolytic solution used was 300 μl of a 30 wt% aqueous solution of potassium hydroxide. After this, the current collector 7B,
The negative electrode lid 8 is placed, swaged and sealed (FIG. 1B).
The current collectors 7A and 7B may be welded to the positive electrode can 4 and the negative electrode lid 8, respectively, or either one of them may be welded. Further, the positive and negative electrodes may be directly welded to the container without using the current collectors 7A and 7B.

In the battery thus assembled, sodium carboxymethylcellulose in the separator material 3 swells inside, and a part thereof is dissolved in the electrolytic solution to form pores 9, and the separator material 3 becomes heat-sealing. It becomes a separator 3 'consisting mainly of polyethylene and consisting of a three-dimensional porous body,
A battery having a separator having excellent electrolyte permeability and excellent ion conductivity is obtained (FIG. 1C). FIG. 2 shows a discharge curve associated with the cycle of the battery obtained in this example.

Example 2 As a material for a separator material, heat-fusible polyethylene 10
Parts by weight, 5 parts by weight of sodium carboxymethylcellulose, and an inorganic powder component white alumina (WA- # 50)
0, an average particle diameter of 34.0 μm), 2 parts by weight of the material for the separator, 60 mg of the material was mixed and placed in the molding die 11 of the molding die apparatus shown in FIG. A battery was fabricated in the same manner as in Example 1 except that a separator material was fabricated by charging, pressing and molding at 120 ° C. and 100 kgw / cm ² for about 30 seconds.

In the battery thus assembled, sodium carboxymethylcellulose in the separator material swells inside, and a part of the battery is dissolved in the electrolytic solution, and the separator material is made of heat-fusible polyethylene in which white alumina is dispersed. The separator is mainly composed of a three-dimensional porous body, and is a battery having a separator having excellent electrolyte permeability and excellent ion conductivity. In addition, by dispersing the white alumina, the liquid retaining property due to the decrease in the thickness of the separator material due to the compressive stress in the caulking step and the deterioration of the battery characteristics due to the decrease in the porosity are less likely to occur.

FIG. 3 shows a discharge curve accompanying the cycle of the battery of this embodiment. Compared with the battery of this example and the battery of Example 1, it can be seen that the battery of this example has a larger discharge capacity for each cycle and a higher electrode utilization.

Comparative Example 1 Same as Examples 1 and 2 except that a polypropylene nonwoven fabric punched into a circular shape so as to have an outer diameter of 20 mm was subjected to an alkaline boiling treatment and used as a separator provided with electrophilicity. To produce a battery. That is, the battery manufactured in the present embodiment is the same as that in the first embodiment except for the separator.
It has the same structure as. FIG. 4 shows a discharge curve associated with the cycle of the battery of this comparative example. Comparing the batteries of Example 1 and Example 2 with the battery of this comparative example, the batteries of Example 1 and Example 2 have a larger discharge capacity for each cycle and a higher electrode utilization rate. You can see that.

Example 3 10 parts by weight of heat-fusible polyethylene, which is a material of the separator of the present invention, and 5 parts by weight of sodium carboxymethylcellulose are mixed. Next, after 60 mg of the mixed separator material was dispensed, it was put into the molding die 11 of the molding die apparatus shown in FIG.
Temporary molding is performed by pressing at 30 kgs / cm ² for 30 seconds. At this time, a molding die 11 having an inner diameter of 20 mm was used.

Next, TiNi, which is the material of the negative electrode, was charged into a pressure-resistant container (not shown), and the temperature was raised to 300 ° C.
Absorb and release gaseous hydrogen at atmospheric pressure, 0.1 Torr
The mixture was gradually cooled to 25 ° C. while being degassed. Then 2
It was stored overnight at 5 ° C. and 1 atm to produce a hydrogen storage alloy. 2 g of this TiNi as the hydrogen storage alloy was put into the molding die 11 containing the temporarily molded separator material according to the present invention, press-molded from above at 700 kgw / cm ² , taken out and cooled. Thus, a separator material was prepared in which the separator material and the negative electrode were bonded and integrated. The capacity of this negative electrode was 150 mAh.

Further, this integrated separator material is
A battery was fabricated in the same manner as in Example 1 by combining the same positive electrode as that used in Example 1. This battery is different from the battery of Example 1 in that the negative electrode and the separator material are bonded and that the negative electrode does not include a Ni wire mesh.

FIG. 5 shows a discharge curve accompanying the cycle of the battery of this embodiment.

The battery of the present embodiment has the same initial discharge capacity as the battery of Embodiment 1, but has a smaller decrease in capacity with cycling. This fall off or from the electrode of the hydrogen storage alloy due to volume variation of the negative electrode hydrogen absorbing alloy caused by charging and discharging cycles, the occurrence of the current collector failure due micronization, Se
This is because the parator material and the negative electrode are pressed by binding . Furthermore, the battery of Example 3 does not require a Ni wire mesh for holding the hydrogen storage alloy of the negative electrode as compared with the battery of Example 1, so that the volume capacity density of the negative electrode can be increased.

Example 4 As materials for a separator, 10 parts by weight of heat-fusible polyethylene, 5 parts by weight of sodium carboxymethylcellulose, and white alumina (WA- # 500, average particle size 3)
4.0 μm), 2 parts by weight of the separator material, 60 mg of the material for the separator were mixed, and the mixture was put into the molding die 11 of the molding die apparatus shown in FIG. ,
A battery was fabricated in the same manner as in Example 3, except that the separator material was temporarily molded by pressing at ²⁰ kgw / cm ² for about 30 seconds and molding.

FIG. 6 shows a discharge curve associated with the cycle of the battery of this embodiment.

Comparing the battery of Example 3 with the battery of this example, it can be seen that the battery of this example has a larger discharge capacity in each cycle and a higher electrode utilization.
In addition, compared to the battery of Example 3, the battery of this example is
The battery has a large capacity and a small decrease in capacity due to cycling.

The battery of this embodiment is different from the battery of Embodiment 2 in that the negative electrode and the separator material are settled and that the negative electrode does not include a Ni wire mesh. The battery of this example has the same initial discharge capacity as the battery of Example 2, but has a smaller decrease in capacity due to cycling. Further, since the battery of the present example does not require a Ni wire mesh for holding the hydrogen storage alloy of the negative electrode, the capacity density of the negative electrode can be increased.

Example 5 10 parts by weight of heat-fusible polytetrafluoroethylene and 4 parts by weight of polyvinyl alcohol, which are materials of a separator material, are mixed. Next, the mixed separator material is put between the hot-rolling forming rolls 17 and 18 heated to 260 ° C. in the roll forming apparatus in FIG. 15 to produce a sheet-like separator material. In the present example, a separator material having a maximum width of 20 cm was continuously produced using a hot-rolled forming roll having a width of 20 cm.

Next, TiNi, which is the material of the negative electrode, is charged into a pressure-resistant container (not shown), and the temperature is raised to 300 ° C.
Absorbs and releases gaseous hydrogen at 0 atm, at the same temperature, 0.
Under a condition of 1 Torr, a degassing treatment was performed overnight to prepare a hydrogen storage alloy. The TiNi, which is a hydrogen storage alloy, was rolled by a roll forming apparatus shown in FIG.
A negative electrode is prepared by processing into a sheet shape integrated with a 00 mesh Ni wire mesh.

Further, as a positive electrode, a sheet-form sintered nickel electrode which is electrochemically subjected to a chemical conversion treatment in an alkaline aqueous solution such as a potassium hydroxide aqueous solution to be discharged is prepared. The capacity of the positive electrode was 500 mAh, and the capacity of the negative electrode was 800 mAh.

The above-described negative electrode, separator material and positive electrode are stacked in this order, spirally wound and mounted in a battery container, and a 30 wt% aqueous solution of potassium hydroxide as an electrolytic solution is supplied.
The container was sealed and an AA nickel-metal hydride battery was assembled.

In the battery of this embodiment, the polyvinyl alcohol in the separator material swells, and a part of the polyvinyl alcohol dissolves and elutes in the electrolytic solution (aqueous potassium hydroxide solution) to remove the heat-fusible polytetrafluoroethylene. The separator is mainly composed of a three-dimensional porous body. Ordinarily, polytetrafluoroethylene is poorly compatible with an electrolytic solution or the like, but the tendency was small in the case of the separator material of the present invention, and was not recognized. Further, this separator was a battery having a separator excellent in electrolyte permeability and excellent ion conductivity.

FIG. 7 shows a discharge curve of this embodiment.

An extra 100 batteries were manufactured in this example, and the occurrence rate of cycle failure was tested. The column of Example 5 in Table 1 shows the number of defective occurrences of the battery of this example every 100 cycles. Here failure The mentioned, open-circuit photoelectric 圧異 normal,
Abnormal discharge voltage, abnormal charge voltage, and a case where the discharge capacity is reduced to 50% or less of the initial capacity.

Example 6 As a material for a separator material, 10 parts by weight of heat-fusible polytetrafluoroethylene, 4 parts by weight of polyvinyl alcohol, and glass beads (average particle size 24 μm, particle size range 15 to
After mixing the material of this separator material using 2 parts by weight of 40 μm), the mixture was put between hot-rolling forming rolls 17 and 18 of 20 cm width heated to 260 ° C. in the roll forming apparatus of FIG. A battery was manufactured in the same manner as in Example 5, except that the sheet-shaped separator material was manufactured.

In the battery of this embodiment, similarly to the battery of Embodiment 5, the polyvinyl alcohol in the separator swells inside the battery, and a part of the polyvinyl alcohol is dissolved and eluted in an electrolytic solution (aqueous potassium hydroxide solution). Then, a separator composed of a three-dimensional porous body mainly composed of heat-fusible polytetrafluoroethylene in which glass beads are dispersed is obtained. Further, the separator material of the battery of this example was a battery having a separator excellent in electrolyte affinity, electrolyte permeability, and ion conductivity, similarly to the battery of Example 5.

FIG. 8 shows a discharge curve associated with the cycle of the battery of this embodiment.

As in the case of the fifth embodiment, an extra 10
Zero devices were manufactured and the occurrence rate of cycle failure was tested. The results are shown in the column of Example 6 in Table 1.

According to the discharge curves, comparing the battery of Example 5 with the battery of this example, the battery of this example has a larger discharge capacity in each cycle and a higher electrode utilization. I understand. Also, from Table 1, it can be seen that the occurrence rate of defects is lower in the battery of the present embodiment than in the battery of Example 5. This is because the battery of the present embodiment has a larger separator thickness than the battery of the fifth embodiment due to the compressive stress during the electrode winding process and the change in the electrode thickness due to the charge / discharge reaction.
This is because there is little deterioration in the liquid retention ability due to the decrease and little deterioration in battery characteristics due to the decrease in the porosity.

Comparative Example 2 Instead of the separator of Example 5, an AA nickel-hydrogen battery was produced using a nonwoven fabric made of polypropylene with a width of 40 mm to which an electrophilic property was imparted by performing an alkali boiling treatment as a separator. . This battery has the same structure as that of the fifth embodiment except for the separator.

FIG. 9 shows a discharge curve of the battery of Comparative Example 2.

Further, 100 extra batteries of this comparative example were manufactured, and the occurrence rate of cycle failure was tested in the same manner as in Example 5. The results are shown in the column of Comparative Example 2 in Table 1.

From the discharge curves, comparing the batteries of Examples 5 and 6 with the battery of this comparative example, the batteries of Examples 5 and 6 have a larger discharge capacity for each cycle, and It can be seen that the usage rate is high. Table 1
Thus, it can be seen that the batteries of Example 5 and Example 6 had a lower failure rate than the battery of this comparative example.

Example 7 A hot roll forming roll 1 was prepared by heating the separator material used in Example 5 to 260 ° C. in a roll forming apparatus shown in FIG.
7 and 18 passed through the same treatment as in Example 5
Ni is evenly spread on a separator material molded into a sheet shape, and further poured into another hot-rolling molding roll heated to 260 ° C. to form a sheet material composed of the separator material and TiNi. A separator material sheet to which the negative electrode was bound was produced. Using this, an AA nickel-metal hydride battery similar to that of Example 5 was produced. The battery of this example is different from the battery of Example 5 in that the negative electrode and the separator are bonded and that the negative electrode does not include a Ni wire mesh.

FIG. 10 shows a discharge curve of the battery of this example.

Further, the battery of this embodiment has an extra 1
00 pieces were manufactured, and the occurrence rate of cycle failure was tested in the same manner as in Example 5. The results are shown in the column of Example 7 in Table 1. Comparing the battery of the present example with the battery of Example 5 based on the discharge curve, the initial discharge capacity is the same, but the capacity of the battery of the present example decreases with cycling less.
Table 1 also shows that the battery of the present example has a lower failure rate than the battery of Example 5.

In this embodiment, the volume capacity density of the negative electrode can be increased since a Ni wire mesh for holding the hydrogen storage alloy of the negative electrode is not required.

Example 8 A hot roll forming roll 1 was prepared by heating the separator material used in Example 6 to 260 ° C. in a roll forming apparatus shown in FIG.
7 and 18 passed through the same treatment as in Example 6
Ni is evenly spread on a separator material molded into a sheet shape, and further poured into another hot-rolling molding roll heated to 260 ° C. to form a sheet material composed of the separator material and TiNi. A separator material sheet to which the negative electrode was bound was produced. Using this, an AA nickel-metal hydride battery similar to that of Example 6 was produced. FIG. 11 shows a discharge curve of the battery of this example.

Further, an extra 100 batteries J of this embodiment were manufactured, and the number of occurrences of defects in each cycle was tested in the same manner as in the fifth embodiment. The results are shown in the column of Example 8 in Table 1.

According to the discharge curves, comparing the battery of Example 7 with the battery of this example, the battery of this example has a larger discharge capacity for each cycle and a higher electrode utilization. I understand. Table 1 also shows that the battery of this example and the battery of Example 8 have a lower failure rate than the battery of Example 8.

Further, the battery of this embodiment is different from the battery of Embodiment 6 in that the negative electrode and the separator are bonded and that the negative electrode does not include a Ni wire mesh. Then, although the initial discharge capacity is the same, the decrease in the capacity due to the cycle is smaller in the present embodiment. Further, since the battery of the present embodiment does not require a Ni wire mesh for holding the hydrogen storage alloy of the negative electrode, the volume capacity density of the negative electrode can be increased.

Example 9 After mixing 10 parts by weight of a modified polypropylene having maleic anhydride as a substituent and 3 parts by weight of polyvinyl alcohol, which are the materials of the separator material of the present invention, the material of the mixed separator material is shown in FIG. The sheet-like separator material was prepared by putting the material between the hot-rolling forming rolls 17 and 18 heated to 180 ° C. in the roll forming apparatus shown in FIG. In this example, a separator material having a maximum width of 20 cm was continuously produced using a roll having a width of 20 cm.

Next, TiNi, which is the material of the negative electrode, was charged into a pressure-resistant container (not shown), and the temperature was raised to 300 ° C.
Absorb and release gaseous hydrogen at atmospheric pressure, at the same temperature, 0.1
Under a Torr condition, a degassing treatment was performed overnight to produce a hydrogen storage alloy. This hydrogen-absorbing alloy, TiNi, was processed by a rolling roll into a sheet integrated with a Ni mesh having a wire diameter of 0.1 mm and 100 mesh to prepare a negative electrode.

Further, as a positive electrode, a sheet-form sintered nickel electrode which was electrochemically converted in an alkaline aqueous solution such as a potassium hydroxide aqueous solution and discharged was prepared. The capacity of the positive electrode was 500 mAh, and the capacity of the negative electrode was 800 mAh.

The above-described negative electrode, separator material and positive electrode are stacked in this order, spirally wound and mounted in a battery container, and a 30 wt% aqueous potassium hydroxide solution as an electrolytic solution is supplied.
The container was sealed and an AA nickel-metal hydride battery was assembled.

As in Example 5, the polyvinyl alcohol in the separator swells inside the battery, and a part of the polyvinyl alcohol dissolves and elutes in the electrolyte (aqueous potassium hydroxide solution).
The separator is a three-dimensional porous body mainly composed of modified polypropylene. According to the present embodiment, a battery having a separator having high electrolyte affinity, excellent electrolyte permeability, and excellent ion conductivity is obtained.

FIG. 12 shows a discharge curve of the battery of this example.

Further, an extra 100 batteries were manufactured, and the occurrence rate of cycle failure was tested in the same manner as in Example 5. The results are shown in the column of Example 9 in Table 1.

This example is different from Example 5 in that modified polypropylene having maleic anhydride as a substituent was used instead of polytetrafluoroethylene as the insoluble polymer material. Comparing the present embodiment with the sixth embodiment, it can be seen that the present embodiment has a larger capacity in each cycle and a higher electrode utilization. In addition, Table 1 shows that the present embodiment and the fifth embodiment are compared with each other, and that the present embodiment has a lower failure rate.

Example 10 As a material for a separator material, 10 parts by weight of a modified polypropylene having maleic anhydride as a substituent, 3 parts by weight of polyvinyl alcohol, and glass beads (average particle diameter of 24 μm) were used.
m, a particle size range of 15 to 40 μm) and 2 parts by weight, and the mixed separator material was heated to 180 ° C. in a roll forming apparatus shown in FIG. A battery was manufactured in the same manner as in Example 9 except that the separator was put into the gap and a sheet-shaped separator material having a maximum width of 20 cm was manufactured. FIG. 13 shows a discharge curve of the battery of this example.

Further, one hundred extra batteries were manufactured, and the occurrence rate of cycle failure was tested in the same manner as in Example 5. The results are shown in the column of Example 10 in Table 1.

Comparing the battery of Embodiment 9 with the battery of this embodiment based on the discharge curves, the battery of this embodiment has a larger discharge capacity for each cycle and a higher electrode utilization. Recognize. Table 1 also shows that the present invention has a lower occurrence rate of defects when the present invention and Example 9 are compared.

[0082] The separator material of the present embodiment, as compared with the separator material of the batteries of Example 9, the compressive stress of or during the electrode winding up process, due to the thickness variation of the electrode due to the charge and discharge reactions, the separator thickness An excellent battery was produced, in which the liquid retention ability was reduced due to the increase / decrease in the porosity and the characteristics of the battery were not significantly deteriorated due to the reduced porosity.

As described above, in the batteries of the present example and the comparative example, the heat sealing was used for molding the separator material and for bonding the negative electrode and the separator material. However, nitrocellulose, polyethylene oxide and the like were used. It is also possible to combine and integrate with molding by a method such as spin casting or the like.
The solution includes a paste-like solution.

In the batteries of this example and the comparative example, only those using TiNi as the negative electrode active material were shown. However, other hydrogen storage alloys, for example, LaNi ₅ or MmNi ₅ (a kind of rare earth alloy) were used. Mm: Mesh metal
A mixture of several lanthanoids) and their Ni, La,
Mm substituted with various transition elements (for example, L
aNi _3.5 Co _0.7 Al _0.8 or MmNi _2.0 Co _2.2 A
l _0.8 ), a ZrV-based alloy, TiCo or the like can also be used.

In general, the positive electrode mixture which is a main component of the positive electrode contains a positive electrode active material, a conductive agent, and a binder. In some cases, a punching metal or a nickel wire mesh obtained by plating a nickel plate on an iron plate may be included as an internal conductor. As the positive electrode active material, for example, manganese dioxide,
Examples of the oxidizing agent include nickel oxide, tungsten trioxide, lead dioxide, and molybdenum trioxide. Of these, manganese dioxide and nickel oxide used in this example are preferable. The conductive agent is an electronic conductive substance added to ensure electronic conductivity in the mixture. Examples of this include acetylene black, artificial graphite, graphite, carbon black, nickel powder, etc., but graphite and nickel powder are preferred. Further, the above-mentioned binder is a substance added to enhance the binding properties and moldability of the two kinds of powders. Examples of this include carboxymethylcellulose, polytetrafluoroethylene, salts of carboxymethylcellulose, polyvinyl alcohol,
Examples include polyethylene, agar, and methylcellulose. The conductive agent and the binder are mixed in the positive electrode mixture in an amount of 3 to 20% by weight.

[0086]

[Table 1]

[0087]

According to the method for producing a battery of the present invention as described above, it becomes unnecessary to treat the separate material with an electrophilic solution before the assembling step.
Since the process of assembling the negative electrode and the separator material can be performed in a dry manner, the possibility that the electrolyte solution leaks into the process in the assembling process is reduced, and the battery is easily assembled. Further, by supplying the electrolytic solution in a state where the positive electrode, the negative electrode, and the separator material are provided in the battery container, the compressive stress applied to the separator material after the placement of the separator material in the battery reduces the soluble stress of the soluble material from the separator material. Since the absorption can be reduced by the elution, the strength of the separator material after the battery is assembled can be secured. Also,
When inorganic powder is dispersed in the parator material,
Even when the parator material is formed into a sheet,
The resistance to compressive stress is improved and the porosity is maintained.
As a result, the liquid retention amount is secured and the rise in internal resistance is suppressed.
Is done. In addition, improved resistance to compressive stress
Reduced separator thickness, resulting in insulation
Heat generation and ignition due to internal short circuit due to destruction and rapid abnormal discharge
Can be prevented and has excellent mechanical strength.
Thus, a large-area separator can be manufactured. Also,
When the inorganic powder is 10 to 100 μm
In particular, the above effects can be obtained.

Further , the polymer material has a polar group.
Good adhesion between polymer materials and inorganic powders,
Further, the affinity with the electrolyte is also improved.

According to the present invention, the hydrogen storage alloy is finely pulverized.
It is possible to prevent the battery characteristics from
Connection to the anode is easy and the capacity density of the negative electrode is large.
And an excellent battery can be manufactured. Furthermore, large
Electrodes with a large area can be easily manufactured, and large-capacity batteries can be easily manufactured.
It is simply.

According to the present invention, as described above,
The compression stress applied to the separator material.
It is possible to provide batteries that are difficult to use.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an assembly process of a battery according to Example 1.

FIG. 2 is a view showing a discharge curve of the battery according to Example 1.

FIG. 3 is a view showing a discharge curve of a battery according to Example 2.

FIG. 4 is a view showing a discharge curve of the battery according to Comparative Example 1.

FIG. 5 is a view showing a discharge curve of the battery according to Example 3.

FIG. 6 is a view showing a discharge curve of the battery according to Example 4.

FIG. 7 is a view showing a discharge curve of the battery according to Example 5.

FIG. 8 is a view showing a discharge curve of the battery according to Example 6.

FIG. 9 is a diagram showing a discharge curve of a battery according to Comparative Example 2.

FIG. 10 is a view showing a discharge curve of the battery according to Example 7.

FIG. 11 is a view showing a discharge curve of the battery according to Example 8.

FIG. 12 is a view showing a discharge curve of the battery according to Example 9.

FIG. 13 is a view showing a discharge curve of the battery according to Example 10.

FIG. 14 is a schematic configuration diagram of a molding die apparatus for molding a separator material of the present invention.

FIG. 15 is a schematic configuration diagram of a roll forming apparatus for forming a separator material of the present invention.

FIG. 16 is a schematic configuration diagram of an ultrasonic welding device for molding a separator material of the present invention.

FIG. 17 is an explanatory diagram for explaining a spin casting method for molding the separator material of the present invention.

FIG. 18 is an explanatory diagram for explaining a spray casting method for molding the separator material of the present invention.

[Explanation of symbols]

1 electrolytic solution 2 negative electrode 3 separator material 3 'separator 4 positive can 6 positive

Claims (5)

(57) [Claims] And 1. A polymeric material having a non-soluble in the predetermined electrolyte, a mixture of a soluble material having a solubility to the electrolyte solution, dispersing the powder of inorganic which does not dissolve in the electrolyte By supplying the electrolytic solution in a state where the positive electrode, the negative electrode, and the separator material are provided in the battery container, the soluble material is separated from the separator material in the battery container by the electrolytic solution. A method for producing a battery, characterized in that the battery is eluted therein. 2. The inorganic powder having a particle size of 10 to 10
The method for producing a battery according to claim 1, wherein the thickness is 0 μm. 3. The method according to claim 1, wherein the polymer material has a polar group. 4. The method according to claim 1, wherein the negative electrode is made of a hydrogen storage alloy, and the electrolyte is supplied in a state where the hydrogen storage alloy and the separator material are bound. Battery manufacturing method. 5. A battery manufactured by the method for manufacturing a battery according to claim 1.