JPH11191400A - Nonaqueous electrolyte battery vessel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the reduction of rechargeability by generation of distortion accompanying the expansion and contraction of an electrode in charge and discharge by forming a vessel by use of a multiple structure having has interrupting property and rigidity, and making it hold hydruscesility and gas absorbability. SOLUTION: A vessel for a battery 1 is formed of a multiple structure having gas interrupting property and rigidity. The multiple structure is formed of a facing can 3 consisting of a rigid material having sealing property, and an inner plastic vessel to be arranged within the facing can 2. The facing can 2 can be made by use of steel or a lightweight metal such as aluminum or titanium which has necessary strength and sealing property as battery vessel. The inner plastic vessel is formed of a box or packing bag 3 consisting of a single-layer or multilayer plastic material. A bygroscopic agent and a gas absorbent are preferably kneaded to the material of the inner plastic vessel to make the inner plastic vessel bygroscopic and gas absorbable. By setting the inner plastic vessel into a bellows structure, the movement of an electrode plate by charge and discharge of a battery can be absorbed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a container for a non-aqueous electrolyte battery capable of obtaining a high voltage and a large capacity which is suitably used for electric power storage, electric vehicles, and the like.

[0002]

2. Description of the Related Art In recent years, as a battery capable of obtaining a high voltage and a high energy density, a material capable of doping and undoping lithium ions such as lithium, a lithium alloy or a carbon material is used as a negative electrode, and a lithium electrode is used as a positive electrode. Research on lithium ion secondary batteries, which are non-aqueous electrolyte batteries using lithium composite oxides such as cobalt composite oxides,
Development is taking place.

The structure of this battery is a cylindrical battery in which a spiral electrode laminate formed by winding flat electrodes is accommodated in a cylindrical metal deep drawing case, or a flat battery in which flat electrodes are laminated. In most cases, the flat electrode type battery in which the electrode stack was housed in a horn-shaped metal deep drawing case was small, and had a small capacity that was small, portable and convenient.

[0004] In a lithium ion secondary battery, if a small amount of water is present, the negative electrode reacts with water to generate hydrogen,
There is a disadvantage of generating heat. Further, when the battery is used, the electrolytic solution may be decomposed to generate corrosive gas such as hydrogen fluoride gas. Furthermore, since the electrodes expand and contract during discharging and charging, distortion occurs in the container that stores the battery,
There is a problem that it is difficult to manufacture a large-sized and large-capacity battery.

[0005]

SUMMARY OF THE INVENTION Accordingly, the present invention solves these problems of the prior art, can absorb a small amount of water and generated gas in a battery, and can expand electrodes during discharging and charging. It is an object of the present invention to provide a battery container that prevents a decrease in rechargeability due to the generation of distortion due to shrinkage and enables the manufacture of a nonaqueous electrolyte battery such as a large-sized and large-capacity lithium ion secondary battery. Is what you do.

[0006]

In order to solve the above-mentioned problems, the present invention has the following arrangement. 1. A container for a non-aqueous electrolyte battery comprising a multiple structure having gas barrier properties and rigidity. 2. 2. The container for a non-aqueous electrolyte battery according to 1, wherein the container has a moisture absorbing property and / or a gas absorbing property. 3. 3. The container for a non-aqueous electrolyte battery according to 1 or 2, wherein the multiple structure comprises an outer can made of a rigid material having a sealing property, and an inner plastic container disposed inside the outer can. 4. 4. The non-aqueous electrolyte battery container according to 3, wherein the interior plastic container comprises a box, a packaging bag, or a combination thereof. 5. 5. The nonaqueous electrolyte battery container according to 3 or 4, wherein the interior plastic container has a multilayer structure. 6. 6. The container for a non-aqueous electrolyte battery according to 5, wherein the multilayer structure includes at least one gas barrier resin layer. 7. The nonaqueous electrolyte battery container according to any one of claims 3 to 6, wherein the interior plastic container is a packaging bag made of a plastic laminated film. 8. 8. The container for a non-aqueous electrolyte battery according to 7, wherein the plastic laminate film is formed by laminating at least one plastic film on both sides of a metal foil as an intermediate layer. 9. The nonaqueous electrolyte battery container according to any one of claims 3 to 8, wherein the interior plastic container has a plastic layer containing a moisture absorbent and / or a gas absorbent. 10. 3-9, wherein the interior plastic container has a heat-sealable plastic layer.
The container for a nonaqueous electrolyte battery according to any one of the above. 11. The nonaqueous electrolyte battery container according to any one of items 3 to 10, wherein the interior plastic container has a bellows structure. 12. 3. A moisture absorbent and / or gas absorbent storage section is provided between the outer can and the inner plastic container.
The container for a non-aqueous electrolyte battery according to any one of claims 11 to 11. 13. The nonaqueous electrolyte battery container according to any one of claims 3 to 12, wherein a pressing member that presses the inner plastic container inward is provided between the outer can and the inner plastic container. 14． 14. The non-aqueous electrolyte battery container according to any one of 3 to 13, wherein the outer can is made of a lightweight metal such as aluminum, titanium, or an alloy thereof. 15. 14. The nonaqueous electrolyte battery container according to any one of 3 to 13, wherein the outer can is made of a plastic material. 16. 3. The container for a non-aqueous electrolyte battery according to 1 or 2, wherein the multilayer structure comprises a laminate including at least an outer layer made of a rigid material and a plastic layer containing a moisture absorbent and / or a gas absorbent. 17． The spouts for fixing the electrode terminals, the spouts for fixing the safety valve, and the caps and the like attached thereto, which are heat-sealed to the multilayer structure, are made of a plastic containing a moisture absorbent and / or a gas absorbent. 16
The container for a nonaqueous electrolyte battery according to any one of the above.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a container for a non-aqueous electrolyte battery is constituted by a multiple structure having gas barrier properties and rigidity. As shown in FIG. 1, the multi-layer structure can be constituted by an outer can made of a rigid material having a sealing property, and an inner plastic container disposed inside the outer can. In addition, as shown in FIG. 8, the multi-layer structure may be constituted by a laminate including at least an outer layer made of a rigid material and a plastic layer containing a moisture absorbent and / or a gas absorbent.

In the present invention, as a material constituting the outer can of the container for a non-aqueous electrolyte battery, a rigid material having strength and sealing properties required for a battery container is used. Examples of such rigid materials include various metal materials, for example, steel, alloys such as chromium and nickel of steel; lightweight metals such as aluminum, titanium and alloys thereof; various surface-treated materials or various resin-coated materials of these metals. Is mentioned.

Also, various plastic materials such as polyethylene resins such as high-density polyethylene, low-density polyethylene, linear low-density polyethylene, polypropylene resins, cyclic polyolefins, nylon, polyester, crystalline polyester and the like; A composite material such as a fiber-reinforced plastic obtained by combining the above plastic material with glass fiber, carbon fiber or the like can also be used as a rigid material constituting the outer can. Among these rigid materials, when a lightweight metal such as aluminum, titanium or an alloy thereof is used, the necessary strength and sealing properties are obtained and the heat dissipation of the battery is improved,
In addition, it is preferable because the weight of the battery can be reduced. In addition, when a plastic material is used for an outer can, it is possible to release a small amount of gas such as hydrogen generated by repetition of charge and discharge in addition to weight reduction, which is advantageous in terms of ensuring safety.

The interior plastic container placed inside the outer can made of a rigid material can be constituted by a box or a packaging bag made of a single-layer or multi-layer plastic material, or a combination thereof. The box used as the interior plastic container can be manufactured by a normal molding method such as vacuum molding, vacuum / pressure molding, injection molding, blow molding, or a combination thereof, and the molding method is not limited. There is no particular limitation on the plastic material to be used, and any thermoplastics usually used for manufacturing plastic containers can be used.Preferred plastic materials include, for example, high-density polyethylene, polyolefins such as polypropylene, polycarbonate, Polyesters such as polyvinyl chloride, polyvinylidene chloride, polyamide, polyacrylonitrile, saponified ethylene vinyl acetate copolymer, and polyethylene terephthalate are exemplified.

The box to be used as the interior plastic container may have a single-layer structure made of these plastic materials. However, in order to improve gas barrier properties, organic solvent barrier properties, moisture barrier properties, etc. Main material layer made of plastic material, saponified ethylene-vinyl acetate copolymer, polyamides such as nylon 6, nylon 66, polyacrylonitrile and its copolymer, polyvinylidene chloride and its copolymer, cyclic polyolefin, etc. It is preferable to constitute the structure having a multilayer structure including at least one gas barrier resin layer made of Further, by using a heat-sealing resin for the inner layer and / or the outer layer, the interior plastic container can be provided with a heat-sealing property.

Further, in order to impart moisture absorption and / or gas absorption to the interior plastic container, a moisture absorbent and / or a gas absorbent may be kneaded into a plastic material constituting the container. Examples of these moisture absorbents and / or gas absorbents include silica gel, molecular sieves such as natural or synthetic zeolites, activated carbon, metal salts of stearic acid, natural or synthetic hydrotalcites, nickel having a hydrogen absorbing function, Examples include metals such as palladium and sintered bodies containing them.

As the lid of the interior plastic container, the same plastic material as that of the container body is used.
Spouts for connecting a safety valve and the like are integrally formed by, for example, injection molding. After the electrodes are housed in the interior plastic container, the lid is heat-sealed or ultra-sealed to the flange portion of the interior plastic container body. It is preferable to configure so as to seal with a sound wave seal or the like. When such a lid is used, the sealing performance of the battery container can be further improved.

In the present invention, the interior plastic container disposed inside the outer can can be constituted by a plastic laminated film packaging bag. Materials suitable for the plastic base film constituting the plastic laminate film serving as the packaging bag include, for example, crystalline polypropylene, crystalline propylene-ethylene copolymer, crystalline polybutene-1, crystalline poly4-methylpentene- 1, polyolefins such as low-, medium- or high-density polyethylene, ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA), ion-crosslinked olefin copolymer (ionomer); Aromatic vinyl copolymers such as polystyrene and styrene-butadiene copolymer; vinyl halide polymers such as polyvinyl chloride and vinylidene chloride resin; acrylonitrile-styrene copolymer, acrylonitrile-styrene-
Nitrile polymers such as butadiene copolymer; polyamides such as nylon 6, nylon 66, para- or meta-xylylene adipamide; polyethylene terephthalate;
Polyesters such as polytetramethylene terephthalate; various polycarbonates; and thermoplastic resins such as polyacetals such as polyoxymethylene. Plastic substrate films made of these materials are used as unstretched or uniaxially or biaxially stretched films.

The plastic base film is laminated on another film via an anchor coat layer if necessary, and becomes a laminated film constituting a packaging bag. As the material for forming the anchor coat layer, an adhesive resin selected from polyethyleneimine resin, alkyl titanate resin, polyester-isocyanate resin, urethane resin, epoxy resin and the like is used. There is no particular limitation on the method of manufacturing the plastic laminated film used in the present invention, and a laminated film is formed at the same time as the formation of the film by co-extrusion, bonding a previously formed film, forming a resin layer by coating on the surface of a metal foil or the like. And can be produced by an ordinary method.

An example of a preferred laminated film is one having an aluminum foil as an intermediate layer and having at least one layer of plastic film on both sides thereof. As such a laminated film, for example, a three-layer film composed of polyethylene terephthalate (PET) / aluminum foil / polypropylene (PP), PE
T / aluminum foil / PET / PP, 4-layer film composed of PET / aluminum foil / modified PP / PP, PET
/ Aluminum foil / modified PP / ethylene propylene random copolymer / ethylene propylene block copolymer. In these films, a PP film having good heat-sealing properties is used as an inner surface, spouts for connecting an electrode terminal, a safety valve, etc. are arranged after the battery is housed, and the PP film portion is heat-sealed and hermetically sealed. When a polyethylene resin is used as the innermost surface of the packaging bag, a polyethylene resin is used as the spout material. The thickness of each film constituting the laminated film can be appropriately selected, but is usually 5 to 200 μm for a plastic film layer, 5 to 50 μm for a metal foil layer of aluminum or the like, preferably 9 μm to avoid pinholes. Above.

In the present invention, the interior plastic container can be constituted by combining the above-mentioned box and a packaging bag made of a plastic laminated film. In order to form an interior plastic container by such a combination, for example, a plastic-laminated packaging bag may be stored inside the box. As shown in FIG. 7, an opening may be partially provided in a box serving as an interior plastic container, and the opening may be covered with a plastic laminate film.

In the present invention, when the container for a non-aqueous electrolyte battery is composed of an outer can made of a hermetically sealed rigid material and an inner plastic container arranged inside the outer can as described above, In addition to improving water and gas barrier properties, a moisture absorbent and / or
Alternatively, it is possible to provide a storage portion for the gas absorbent, and it is possible to completely remove moisture and to remove corrosive gas such as hydrogen fluoride gas generated. As the moisture absorbent and the gas absorbent, those described above can be used. These moisture absorbents and gas absorbents can be used as they are in powder or granular form in the intermediate space between the outer can and the inner plastic container, or in a nonwoven bag or the like, or by using a carrier. It may be formed into a sheet and inserted between the outer can and the inner plastic container. In addition, these moisture absorbents and gas absorbents are used as boxes for interior plastic containers or packaging bags made of plastic laminate film, for example, outer layers, spouts for fixing electrode terminals, spouts for fixing safety valves which are heat-sealed to interior plastic containers, and By kneading it into a member such as a cap attached thereto, the container can have water and gas barrier properties.

Further, in a lithium ion secondary battery in which a large number of positive and negative electrode plates are alternately stacked via a separator, the electrode plates expand and contract with discharge and charge, and distortion occurs between the electrode plates. Although the rechargeability occurs and the rechargeability deteriorates, in the present invention, it is possible to provide a pressing spring for pressing the inner plastic container inward between the outer can and the inner plastic container by forming the battery container into a double structure. Thus, the distortion generated between the electrode plates can be eliminated. Various elastic materials can be used as such a pressing spring. For example, a plate spring formed in a dish shape, an elastic resin material such as rubber or an elastomer resin, or the like can be used. This pressing spring is usually fixed to the outer can by bonding or mechanical fixing in the direction of compressing the interval between the electrode plates housed in the inner plastic container in the battery container, but only on one side of the container. May be provided on both sides of the container.

Furthermore, in order to absorb the movement of the pressing spring corresponding to the expansion and contraction of the electrode plate due to the discharging and charging of the battery,
The interior plastic container can be provided with a bellows structure. The bellows structure can be formed on the entire interior plastic container (in the case of a plastic laminated film packaging bag), or may be partially formed on the interior plastic container. (See FIG. 6) Also, an opening is partially provided in a box serving as an interior plastic container, and the opening is covered with a plastic laminate film to provide flexibility, and a pressing spring is provided to cope with expansion and contraction of the electrode plate. May be absorbed. (See Fig. 7)

As another embodiment of the container for a non-aqueous electrolyte battery of the present invention, as shown in FIG. 8, a multi-layered structure to be a container for a battery is formed by forming at least an outer layer made of a rigid material, a moisture absorbent and / or a gas. It can be constituted by a laminate including a plastic layer containing an absorbent. FIG. 8 is a schematic cross-sectional view showing a battery container main body. In FIG. 8, reference numeral 31 denotes a battery container main body, reference numeral 32 denotes an outer layer made of a rigid material, and reference numeral 33 denotes a moisture absorbent and / or a gas absorbent. Represents a plastic layer.

Examples of the rigid material constituting the outer layer 32 include various metal materials, for example, steel, alloys such as chromium and nickel of steel; lightweight metals such as aluminum, titanium and alloys thereof; A resin coating material may be used. In addition, various plastic materials such as polyethylene resins such as high-density polyethylene, low-density polyethylene, and linear low-density polyethylene, polypropylene resins, cyclic polyolefins, and various plastic materials such as nylon, polyester, and crystalline polyester, and these plastic materials A composite material such as fiber reinforced plastic, which is a combination of glass fiber, carbon fiber, and the like, can also be used as a rigid material constituting the outer can.

There is no particular limitation on the plastic material constituting the inner layer 33, and any thermoplastics usually used for manufacturing plastic containers can be used. Preferred plastic materials are, for example, high-density polyethylene, polypropylene and the like. Polyolefins, polycarbonate, polyvinyl chloride, polyethylene terephthalate and the like. The above-mentioned moisture absorbent and / or gas absorbent is mixed into the plastic material constituting the inner layer 33 by kneading or the like.

The inner layer 33 may have a single-layer structure. However, in order to improve the gas barrier property, organic solvent barrier property, moisture barrier property, etc. -At least one layer of gas barrier resin comprising saponified vinyl acetate copolymer, polyamide such as nylon 6, nylon 66, polyacrylonitrile and its copolymer, polyvinylidene chloride and its copolymer, cyclic polyolefin and the like. You may comprise as what has a multilayer structure containing a layer. Inner layer 3
When 3 has a multilayer structure, the moisture absorbent and / or the gas absorbent can be blended in one or more resin layers constituting the inner layer. Further, as shown in FIG. 9, a heat sealing resin layer 34 is provided inside the inner layer 33, and a lid (not shown) made of the same material as the battery container main body 31.
May be improved in heat sealing properties. These multiple structures are blow-molded, vacuum-formed, vacuum / pressure-formed, injection-molded, insert-injected-molded, drawn and ironed using a metal plate by pressing,
Alternatively, it can be produced by a usual molding method such as a combination thereof, and the molding method is not particularly limited.

[0025]

The present invention will be described in more detail with reference to the following examples, which do not limit the present invention. (Preparation of Plastic Laminated Film) As a layer structure, biaxially stretched PET (thickness 16 μm) / aluminum foil (thickness 15 μm) / maleic anhydride-modified PP (thickness 5 μm)
m) / ethylene propylene random copolymer (thickness 10
μm) / ethylene propylene block copolymer (thickness 9
0 μm) was produced by the following procedure. Between an aluminum foil layer of a two-layer film obtained by dry laminating biaxially stretched PET and aluminum foil using a urethane-based adhesive, and an ethylene propylene block copolymer film serving as an inner surface layer of an interior plastic container (packaging bag). , Maleic anhydride-modified PP and ethylene propylene random copolymer having a layer thickness of 5 μm and 10 μm, respectively.
m and sandwich lamination, and then a melt heat treatment at a temperature of 180 ° C. in order to achieve sufficient adhesion between the aluminum foil and the modified polypropylene, and finally curing of the urethane adhesive. Was carried out at 55 ° C. for 4 days to obtain an original film for producing a packaging bag as an interior plastic container.

(Preparation of a packaging bag to be used as an interior plastic container) The raw film prepared above is unwound from a pair of rolls slit to a width of 48 cm, and the two sheets are opposed to each other while being folded 5.5 cm on each side, and both ends are set in the vertical direction. Heat-sealed with a hot plate, and then heat-sealed at a pitch of 48 cm at the bottom in the lateral direction and cut into pieces. The approximate inner dimensions are 21 cm in the width direction of the raw fabric, 21 cm in the perpendicular direction, and 22 cm in height. A gusset-type packaging bag was prepared. As the sealing conditions, the seal width of each seal portion was 22 mm,
Heat plate set temperature 220 ± 10 ° C, seal pressure 4.2 ±
At 0.5 kg / cm ² , the ^two films were pressed against the hot plate twice and the cooling plate twice in the longitudinal direction, and the horizontal direction with the four films was pressed three times against the hot plate and the cooling plate twice, and sealed.

(Assembly of electrode) LiC as a positive electrode current collector
Current collectors were prepared using oO ₂ and natural graphite as a negative electrode current collector, respectively, using vinylidene fluoride resin as a binder. A 20 cm × 20 cm plate-like material was used, and a 50 μm thick PP microporous film of 21 cm × 21 cm larger than the current collector for preventing short circuit was used as a separator. An electrode plate side-by-side electrode unit having an approximate outer dimension of 20 cm × 20 cm × 20 cm, in which 700 sets of the electrode plates were stacked alternately in the order of the negative electrode current collector, was assembled.

Next, the sealing of the electrodes and the assembly of the battery in a packaging bag serving as an interior plastic container will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view of one example of a nonaqueous electrolyte battery using a battery container (double structure container) having a multi-structure body of the present invention, and FIG. 2 is an interior plastic of a battery container of the present invention. (A) shows a state before the stacked electrode unit is inserted, and (B) shows a state after the stacked electrode unit is inserted. FIG. 3 is a view showing each member of a non-aqueous electrolyte battery using the battery container of the present invention before assembly.

In these figures, reference numeral 1 denotes a battery, reference numeral 2 denotes an outer can, reference numeral 3 denotes a packaging bag made of a plastic laminated film, reference numeral 4 denotes an outer can lid, and reference numeral 5 denotes an outer can main body 2.
And an O-ring for fixing the lid 4. Reference numeral 6 denotes a dish-shaped pressing spring for pressing the packaging bag 3 containing the laminated electrode plate,
Reference numeral 7 denotes a positive electrode plate, reference numeral 8 denotes a negative electrode plate, and reference numeral 9 denotes a separator. Reference numeral 11 denotes an electrode terminal fixing spout, reference numeral 12 denotes a safety valve fixing spout, and reference numeral 13.
Denotes an O-ring, and reference numeral 14 denotes an O-ring fixing cap.

(Electrode Encapsulation in Packaging Bag) The previously assembled electrode unit is inserted after the gusset-type packaging bag 3 prepared previously is spread out in a cubic shape (see FIG. 2), and comes out from the current collector. Each of the terminals is bundled and further screwed to a copper cylindrical electrode terminal. This electrode terminal is a positive electrode, a negative electrode terminal, a spout 11 for fixing a safety valve by injection molding, which is produced for heat sealing with the resin on the inner surface of the packaging bag.
12, an O-ring made of fluororesin (trade name: Viton)
Fixed through. Next, after the open end of the gusset-type packaging bag 3 is folded into a predetermined shape, the spouts 11 and 12 are heat-sealed at two end portions of the film with a heat seal bar adapted to the spout shape. . Film 4
Sufficient heat sealing was performed separately on the sheet portions. Next, the laminated electrode unit is pushed back vertically from the laminated surface so as to restore the original gap when the distance between the electrodes is expanded during repeated charging and discharging so as to face the side surface of the packaging bag 3 against the side wall of the outer can 2. A plate-shaped pressing spring 6 is attached.
Further, the positive electrode, the negative electrode terminal, and the safety valve fixing spouts 11 and 12 protruding from the packaging bag 3 are each made of fluororesin O.
Cap-shaped component 1 formed with a threaded portion via ring 13
4 and hermetically sealed to the outer can lid 4. Furthermore, outer can lid 4
Is sealed and fixed at the flange portion of the outer can through a fluororesin O-ring 5. These assembly operations are performed at a relative humidity of 1
Conduct in a dustproof and dry room of less than 0%.

(Injection of electrolytic solution)
Further, after repeating the operation of purging with absolute dry nitrogen three times, as an electrolytic solution, an organic solvent of ethyl carbonate (EC) / diethyl carbonate (DEC) having a water content of less than 20 ppm and a mixing ratio of 7/3 was used. An organic electrolyte in which LiPF ₆ was dissolved at a concentration of 1 mol / liter was used as an electrolyte, and this was injected from the safety valve 12 and sealed with a cap.

Next, battery containers having various structures were prepared, and the container structure was tested to determine whether the battery performance, particularly, stable charge / discharge characteristics after repeated charging / discharging for a long period of time, was examined. We sought to determine whether or not is sufficient. (Example 1) Multi-stage deep drawing of aluminum material, thickness 3 mm, inner dimensions 22 cm long, 22 cm wide, depth 22 c
At m, the battery case of FIG. 1 was constructed by combining the outer can of the corner portion 10R and the packaging bag made of the plastic laminate film prepared above. A pressing spring 6 for pressing the packaging bag from one side is provided between the outer can 2 and the packaging bag 3.

(Example 2) The minimum thickness of injection-molded polypropylene was 6 mm, the inner dimension was 22 cm in length,
The battery container shown in FIG. 1 was constructed by combining an outer can having a width of 22 cm and a depth of 22 cm with a corner portion 10R and the plastic laminate film packaging bag prepared above. A pressing spring 6 for pressing the packaging bag from one side is provided between the outer can 2 and the packaging bag 3.

(Comparative Examples 1 to 4) For comparison, a steel material was subjected to multi-stage deep drawing to a thickness of 5 mm and an inner dimension of 21 c in length.
m, width 21 cm, depth 21 cm, and the container and the lid material at the corner 10R are used alone (Comparative Example 1), the minimum thickness of polypropylene injection molded is 6 mm, the inner dimensions are 21 cm long, 21 cm wide, 21 cm deep , Using the container and lid material of the corner portion 10R alone (Comparative Example 2), using the previously produced plastic laminated film packaging bag alone (Comparative Example 3), and using the previously produced plastic laminated film packaging A battery container was constituted by using a 2 mm-thick aluminum panel outside the bag as a protective material for the packaging bag on the side, bottom, and lid (Comparative Example 4). In the container of Comparative Example 4, the packaging bag communicates with the outside air, and has a configuration different from that of the container using the hermetically sealed outer can of the present invention.

(Practical charge / discharge test) In the containers of these examples, the electrode unit was sealed as described above, and a continuous operation test in which charge and discharge were repeated at room temperature was performed. It is shown in Table 1. In Table 1, the efficiency maintenance rate represents the maintenance rate (%) with respect to the initial value of the electromotive force after repeated operation and charging / discharging for 200 days.
Electromotive force per unit weight of battery (V / k) after continuous operation for 00 days
g).

[0036]

[Table 1]

According to the results, the one using the conventionally proposed metal material such as steel alone (Comparative Example 1) was:
Although the efficiency maintenance rate is somewhat good, the electromotive force per unit weight of the battery is low because the weight is heavy. In addition, since the metal material comes into direct contact with the electrolyte, corrosion of the metal surface and deterioration of the electrolyte occur.To guarantee stable use for several years, expensive alloys and surface treatments are required. It is also disadvantageous in terms of reuse. The one using the plastic material alone (Comparative Example 2) is excellent in terms of weight reduction and strength of the battery, but has limited gas barrier properties of the plastic itself, and particularly promotes the decomposition and deterioration of the electrolyte. Because of the high water permeability, the charging performance is significantly reduced due to the decomposition and deterioration of the electrolyte.

[0038] Further, in the case of using the aluminum laminate film alone (Comparative Example 3), no matter how much the laminate structure having excellent strength is used, it is possible to avoid the occurrence of pinholes when assembling the battery container. In addition, there is a problem in the safety of the container such that the container may be damaged when it is pierced with a needle-shaped object from the outside, and the battery may be fired, which is a fatal defect of this type of battery. In this case, it is theoretically impossible to provide a pressing spring or the like in order to recover the gap between the electrodes. Also, in the case of Comparative Example 4 which is used in this type of battery for conventional mobile communication and the like, the penetration of moisture from the seal edge of the aluminum laminate cannot be ignored, and the corrosiveness due to the deterioration of the electrolyte solution Due to the generation of gas, corrosion occurs on the aluminum panel surface, and it is difficult to use it stably for a long period of time.

On the other hand, the first and second embodiments of the present invention using a double-sealed container having an outer can and an aluminum laminate packaging bag.
In each case, practical battery characteristics were obtained. When the outer can is made of plastic, there is a slight decrease in charging efficiency during continuous operation, and a metal outer can is preferred for longer-term stable use. Since the proportion of the weight of the electrode unit and electrolyte in the weight of the entire battery is large, it is possible to reduce the total weight by using aluminum and titanium materials that are relatively thin and have a minimum thickness sufficient to protect the packaging bag. This is advantageous from the point of reuse of the outer can and the like.

In the following examples, in addition to the specifications for the battery container of Example 1, various types of hygroscopic agents and / or gas absorbents were used, and their effects on battery function were evaluated. (Example 3) Two bags of nonwoven fabric (50 in FIG. 4) in which 50 g of silica gel as a moisture absorbent and 50 g of synthetic zeolite as a gas absorbent were mixed and filled in the space between the outer can of the battery container of Example 1 and the packaging bag. Was placed.

(Example 4) In the battery container of Example 1, 1% by weight of a gas absorbent occupying 70% of the layer thickness was used as an ethylene propylene block copolymer film as an inner layer constituting a packaging bag. A packaging bag was constructed using a two-layer film composed of a copolymer film into which kneaded synthetic hydrotalcite was incorporated and an additive-free copolymer film, and the additive-free layer serving as a heat-sealing surface.

(Example 5) In the battery container of Example 1, as a spout for fixing an electrode terminal and a spout for fixing a safety valve, those obtained by kneading 3% by weight of synthetic zeolite into a PP resin and injection molding were used. .

(Example 6) The packaging bag of the battery container of Example 1 was made of PET (thickness 15 μm) / LLDPE (thickness 50).
μm) / aluminum foil (thickness 20 μm) / PET (thickness 25 μm) / PP (thickness 70 μm). As the LLDPE film, a film prepared by previously kneading 1% by weight of synthetic hydrotalcite and 1% by weight of synthetic zeolite was used.

(Example 7) In the space between the outer can of the battery container of Example 1 and the packaging bag, 50 g of silica gel as a moisture absorbent was added.
Two nonwoven fabric bags mixed and filled with 50 g of synthetic zeolite as a gas absorbent, and a plate-like nickel-based hydrogen absorbing sintered body weighing about 100 g were arranged.

A continuous operation test in which the electrode units were sealed in the battery containers obtained in Examples 3 to 7 in the same manner as in Examples 1 and 2 and charging and discharging were repeated at room temperature for one year. The efficiency maintenance rate was evaluated, and the generation of gas accompanying the decomposition and deterioration of the current collector and the electrolyte due to continuous use was evaluated. In the gas analysis of the inner space of the outer can, gas in the space was collected by a microsyringe, and the gas composition was analyzed by gas chromatography. The water content of the electrolytic solution was evaluated by the Karl Fischer method, and the amount of hydrofluoric acid was evaluated by a titration method. The results are summarized in Table 2. In Table 2, the efficiency maintenance rate indicates the maintenance rate (%) with respect to the initial value of the electromotive force after repeated operation and charging and discharging for one year.

[0046]

[Table 2]

According to these results, in the present invention, in addition to the double sealed structure of the outer can and the packaging bag, various forms of the hygroscopic agent and / or the gas absorbent are used to remove moisture and remove gas. It can be seen that the exclusion function can be provided and the battery life can be further stably extended. The water content in the electrolytic solution is an index for predicting long-term battery life, and it is generally desirable to maintain the content at 20 ppm or less, and by providing a water absorbing function to the battery container by any of the above methods, It can be kept much lower than this limit level (particularly, Example 3).

Further, by using hydrotalcite or the like, it becomes possible to trap hydrofluoric acid which is generated by decomposition of the electrolytic solution and corrodes the container member (especially, Example 4). And
By using molecular sieves, etc., in addition to removing water, it can also remove the decomposition gas components (carbon monoxide, ethylene, acetylene, etc.) of the electrolytic solution that are generated in trace amounts due to long-term charge / discharge, and are safe in addition to battery functions. (Examples 3, 5, and 6). Further, by employing a double structure, hydrogen generated in a small amount by charge / discharge can be completely trapped (especially, Example 7). As shown in these examples, it can be understood that improvement in battery performance, safety, and the like, which cannot be achieved by a single sealed structure, can be achieved only by adopting the double structure of the outer can and the packaging bag.

FIG. 5 is a view showing another example of the container for a non-aqueous electrolyte battery according to the present invention, and is a schematic view showing each member constituting the battery container before assembly. In FIG. 5, reference numeral 23 indicates a plastic box, reference numeral 24 indicates an outer can lid, and reference numeral 2
Reference numeral 5 denotes a frame, and other reference numerals denote the same members as in FIGS. In this example, a plastic box 23 is used as an interior plastic container for housing an electrode plate module constituting a non-aqueous electrolyte battery. The plastic box 23 containing the electrode plate module is made of an outer can 2 made of a rigid material.
Is placed within. On the box 23, a plastic outer can lid 24 integrally formed with an electrode terminal fixing spout 11, a safety valve fixing spout 12, a fluororesin O-ring 5, and a frame 25 are sequentially placed. O-ring 13 and O-ring fixing cap 14 are integrally fixed.

In the following embodiment, an aluminum outer can having the same structure as that of the first embodiment is used as the outer can 2 in FIG. 5, and a plastic box 23 is manufactured by various molding methods. Was assembled and its performance was evaluated. (Example 8) As an interior plastic container, an average wall thickness of 0.8 m comprising two layers of high density polyethylene (HDPE) / linear low density polyethylene (LLDPE) from the outer layer.
m, and an opening for inserting the electrode plate module is provided on the upper part of the blow molded body. Then, a flange for sealing the lid is heated so that LLDPE of the inner layer serves as a sealing surface with the lid. Molded, inner dimensions 21cm x 21cm,
A 21 cm deep plastic box was made. Using a high-density polyethylene as a lid, a lid having two electrode terminal fixing spouts and a safety valve fixing spout having a minimum wall thickness of 2 mm was produced by injection molding to form a battery container shown in FIG. In this example, the electrode module was vertically held down by a metal spring from the outside of the interior plastic container.

(Embodiment 9) In the container of Embodiment 8, 50 g of hydrotalcite and molecular sieve 13X are sealed in a small bag made of a microporous air-permeable film in the intermediate space between the outer can and the inner plastic container. did. In this example, the electrode module was vertically held down by a metal spring from the outside of the interior plastic container.

Example 10 As an interior plastic container, a high-density polyethylene / linear polyethylene-based maleic anhydride-modified resin / cyclic polyolefin containing 5000 ppm of hydrotalcite from the outside (glass transition temperature of 85)
C) / linear polyethylene-based maleic anhydride-modified resin / blow-molded body having an average wall thickness of 0.8 mm consisting of five layers of three types of high-density polyethylene containing 5000 ppm of hydrotalcite, and an electrode plate module on the top. An opening for insertion is provided, and then a flange for sealing the lid is thermoformed to have an inner size of 21 cm × 21 cm and a depth of 21 cm.
cm plastic box was made. Hydrotalcite 5000 having two spouts for fixing electrode terminals with a minimum thickness of 2 mm and one spout for fixing a safety valve as a lid.
A lid made of high-density polyethylene containing ppm was manufactured by injection molding, and the battery container of FIG. 5 was configured.

(Example 11) As an interior plastic container, molecular sieve 13X, 3000 pp
m-containing block polypropylene with ethylene content of 4 mol% / maleic anhydride-modified polypropylene / ethylene-vinyl acetate copolymer saponified with ethylene content of 32 mol% / maleic anhydride-modified polypropylene / molecular sieve 13X, ethylene content of 3000 ppm The inner size is 21cm × 21c by vacuum / pressure molding from a sheet consisting of 3 layers and 5 layers of 4% by mole of block polypropylene.
A 21-cm deep cup-shaped container with a flange was prepared. As a lid, a polypropylene lid containing 5000 ppm of hydrotalcite having two spouts for fixing electrode terminals and a spout for fixing a safety valve having a minimum thickness of 2 mm was prepared by injection molding, and the battery container of FIG. 5 was prepared. Configured.

(Example 12) As interior plastic containers, molecular sieve 13X, block polypropylene / maleic anhydride-modified polypropylene / nylon 6 / absolute maleic acid-modified polypropylene / hydrotalcite containing 3000 ppm of ethylene content of 4 mol% were used.
A flanged cup-shaped container having an inner size of 21 cm × 21 cm and a depth of 21 cm composed of five layers of three kinds was prepared by multilayer injection molding so as to form a random polypropylene having an ethylene content of 7 mol% containing 000 ppm. As a lid, a polypropylene lid containing 5000 ppm of hydrotalcite having two spouts for fixing electrode terminals and a spout for fixing a safety valve having a minimum thickness of 2 mm was prepared by injection molding, and the battery container of FIG. 5 was prepared. Configured.

(Example 13) In the same manner as in Example 11, a cup-shaped container obtained by vacuum / pressure molding from a multilayer sheet was produced. As shown in FIG. 6, the electrode module is vertically moved by a metal spring from the outside of the interior plastic container 23 in which bellows-like processed portions 26 are formed by thermoforming at portions corresponding to both side surfaces of the electrode module of this container. A battery container was produced in the same manner as in Example 11, except that the container was pressable.

(Example 14) In the multilayer injection molding of Example 12, a mold was modified so that a square opening of 15 cm x 15 cm was provided at portions corresponding to both side surfaces of the electrode module of the container to produce a cup-shaped container. did.
PET (25 μm) / aluminum foil (30 μm) / PET, as shown in FIG.
(17 μm × 17 cm) laminated film 2 composed of (25 μm) / block PP film (90 μm)
8 are heat-sealed, and the interior plastic container 2
3 was produced. In other respects, a battery container was manufactured in the same manner as in Example 12.

Using the battery containers obtained in Examples 8 to 14, the previously assembled electrode unit is sealed, filled with an electrolyte, and sealed to assemble the battery. Similarly, the battery performance after one year of continuous operation was evaluated.
Table 3 shows the results.

[0058]

[Table 3]

In Table 3, in the column of weight, the upper row shows the total weight of the battery container member, and the lower row () shows the total weight of the battery. Further, the efficiency maintenance rate indicates a maintenance rate with respect to an initial value of the electromotive force after the battery has been continuously operated for one year and repeated charging and discharging, and the electromotive force indicates an electromotive force per unit weight of the battery after the continuous operation for one year. In these batteries, since the entire container is lightened, the electromotive force per unit weight of the battery after one year of continuous operation increases, and the efficiency maintenance rate hardly decreases. In addition, compounding a gas absorbent in the container constituent material,
By arranging the gas absorbent in the battery container, the stability of the electrolytic solution is maintained, and the performance of the battery can be maintained for a long time. Furthermore, by providing a metal spring outside the interior container, a higher voltage can be obtained more stably.

In each of the above embodiments, an example in which the present invention is applied to a lithium ion secondary battery has been described. However, the present invention is required to have similar container performance such as prevention of deterioration of an electrolytic solution and reduction of generated gas. It goes without saying that the present invention can be applied to other nonaqueous electrolyte batteries such as a sodium-sulfur battery and batteries using various polymer electrolytes. Also, the present invention
The present invention is not limited to the above-described embodiments, and may take various other configurations without departing from the gist of the present invention.
Of course.

[0061]

According to the present invention, it is possible to absorb a small amount of water and generated gas in the battery, and to lower the rechargeability due to the generation of distortion due to the expansion and contraction of the electrode during discharging and charging. And a container for a battery capable of manufacturing a non-aqueous electrolyte battery such as a large-sized and large-capacity lithium ion secondary battery can be obtained. By using the battery container of the present invention, it is possible to manufacture a non-aqueous electrolyte battery such as a lithium ion secondary battery that can be used for about 5 years. In addition, the battery container of the present invention has a double sealed structure composed of an outer can made of a rigid material and an inner plastic container, so that the battery can be lightened and the battery main body can be inserted after the use period has elapsed. By replacing the interior plastic container, the outer can can be reused, which reduces waste and contributes to resource saving, and is of high practical value.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of a non-aqueous electrolyte battery using a battery container of the present invention.

FIGS. 2A and 2B are schematic cross-sectional views of a packaging bag serving as an internal plastic container of a battery container according to the present invention, as viewed from above, wherein FIG. 2A is a state before a laminated electrode unit is inserted, and FIG. Is shown.

FIG. 3 is a schematic diagram showing each member before assembling constituting a nonaqueous electrolyte battery using the battery container of the present invention.

FIG. 4 is a schematic cross-sectional view showing another example of a non-aqueous electrolyte battery using the battery container of the present invention.

FIG. 5 is a view showing another example of the battery container of the present invention;
It is a schematic diagram which shows each member before assembling.

FIG. 6 is a view showing another example of the interior plastic container constituting the battery container of the present invention.

FIG. 7 is a view showing another example of the interior plastic container constituting the battery container of the present invention.

FIG. 8 is a schematic sectional view showing another example of the battery container of the present invention.

FIG. 9 is a schematic sectional view showing another example of the battery container of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Battery 2 Outer can 3 Packaging bag made of plastic laminated film 4, 24 Outer can lid 5, 13 O-ring 6 Press spring 7 Positive electrode plate 8 Negative electrode plate 9 Separator 11 Spout for fixing electrode terminal 12 Spout for fixing safety valve 14 O Ring fixing cap 21 Non-woven fabric bag 23 Plastic box 25 Frame 31 Battery container main body 32 Outer layer made of rigid material 33 Absorbent-containing plastic layer 34 Heat-sealing resin layer

Continued on the front page (72) Inventor Izumi Takahashi 4-28-24 Shimoigusa, Suginami-ku, Tokyo (72) Inventor Kazuo Kobayashi 5-4-23 Higashifushimi, Hoya-shi, Tokyo

Claims (17)

[Claims] 1. A container for a non-aqueous electrolyte battery comprising a multilayer structure having gas barrier properties and rigidity. 2. The non-aqueous electrolyte battery container according to claim 1, wherein the container has a moisture absorbing property and / or a gas absorbing property. 3. The non-aqueous water according to claim 1, wherein the multi-layer structure comprises an outer can made of a rigid material having a hermetic property, and an inner plastic container disposed inside the outer can. Container for electrolyte battery. 4. The non-aqueous electrolyte battery container according to claim 3, wherein the interior plastic container comprises a box, a packaging bag, or a combination thereof. 5. The non-aqueous electrolyte battery container according to claim 3, wherein the interior plastic container has a multilayer structure. 6. The non-aqueous electrolyte battery container according to claim 5, wherein the multilayer structure includes at least one gas barrier resin layer. 7. The container for a non-aqueous electrolyte battery according to claim 3, wherein the interior plastic container is a packaging bag made of a plastic laminated film. 8. The non-aqueous electrolyte battery container according to claim 7, wherein the plastic laminate film is formed by laminating at least one plastic film on both sides of a metal foil as an intermediate layer. 9. The non-aqueous electrolyte battery according to claim 3, wherein the interior plastic container has a plastic layer containing a moisture absorbent and / or a gas absorbent. Container. 10. The nonaqueous electrolyte battery container according to claim 3, wherein the interior plastic container has a heat sealable plastic layer. 11. The nonaqueous electrolyte battery container according to claim 3, wherein the interior plastic container has a bellows structure. 12. The non-aqueous electrolyte according to claim 3, wherein a moisture absorbent and / or a gas absorbent storage section is provided between the outer can and the inner plastic container. Battery case. 13. The non-aqueous electrolysis according to claim 3, wherein a pressing member for pressing the inner plastic container inward is provided between the outer can and the inner plastic container. Container for liquid battery. 14. The non-aqueous electrolyte battery according to claim 3, wherein the outer can is made of a light metal such as aluminum, titanium, or an alloy thereof. container. 15. The non-aqueous electrolyte battery container according to claim 3, wherein the outer can is made of a plastic material. 16. The non-woven fabric according to claim 1, wherein the multilayer structure comprises a laminate including at least an outer layer made of a rigid material and a plastic layer containing a moisture absorbent and / or a gas absorbent. Container for water electrolyte battery. 17. The spout for fixing an electrode terminal, the spout for fixing a safety valve, and a member attached to the spout for fixing a safety valve, which are heat-sealed to the multiple structure, are made of a plastic containing a moisture absorbent and / or a gas absorbent. The container for a nonaqueous electrolyte battery according to claim 1, wherein the container is a nonaqueous electrolyte battery.