JP2001256933A - Battery and battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery that is small in volume and, when a plurality of batteries are laminated, that does not produce a plurality of small dead spaces along side faces of the battery laminated body. SOLUTION: Battery elements 1 are interposed between an armored material 2, 3, whose peripheral portions 2a, 3a are mutually joined to form joined pieces 4A, 4F. The battery is formed by folding the joined pieces 4A, 4F and sticking to sides of cover portion 4B that covers the battery elements 4 with an adhesive 5. Leads 21 are drawn out through a joint face of the armored material 2, 3 at the joined piece 4F.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery in which a battery element is wrapped with an exterior material and a battery pack using the battery, and more particularly to a battery and a battery pack suitable for a non-aqueous secondary battery such as a lithium secondary battery. About.

[0002]

2. Description of the Related Art As a thin battery, a thin battery in which a thin battery element (for example, a power generation element composed of a laminate of a positive electrode, a separator and a negative electrode) is covered with a laminate film is known as disclosed in Japanese Patent Application Laid-Open No. 8-83596. After the battery element is inserted into the laminate exterior material, the inside of the laminate exterior material is decompressed, and a pressing force in the stacking direction is applied to the battery element to increase the adhesion between the layers.

In recent years, as shown in FIG. 6, there has been used a battery in which the periphery of an exterior material is bent to reduce the bulk.

In the battery shown in FIG. 6, the battery element 1 is sandwiched between two exterior members 2 and 3 and the outer edges of the exterior members 2 and 3 are pressed or welded to each other. Battery element 1 is rectangular. Joint pieces 4A, 4 formed by joining the peripheral edges of the exterior materials 2, 3
F and 4G extend outward from four sides of the enclosing portion 4B of the battery element 1. The joining pieces 4A, 4A extending from the pair of parallel sides of the battery element 1 are bent so as to overlap the side surfaces of the enclosing part 4B.

[0005] A pair of leads 21 are connected to the battery element 1, and the leads 21 are drawn out through the mating surfaces of the exterior members 2 and 3 in the joint piece portion 4F. The joining piece 4F is not bent along the envelope 4B but protrudes outward from the envelope 4B in a flange shape.

[0006]

SUMMARY OF THE INVENTION Japanese Patent Application Laid-Open No. 8-83596
In the battery disclosed in Japanese Patent Application Laid-Open Publication No. H10-209, the joint pieces of the laminated films are extended outward from the encapsulation part enclosing the battery element, and only the joint pieces protrude. Batteries are bulky.

[0007] In the battery shown in FIG.
Only overhangs, and the two-sided joint pieces 4A, 4A
B is folded so as to overlap the side surface of B, and has a smaller bulk than the battery of JP-A-8-83596.

[0008] In the battery shown in FIG.
And a corner portion 4H at the end of the joining piece portion 4A and a covering portion 4B.
Usually, a control circuit board (not shown) for controlling charging and discharging of the battery is installed in the recess surrounded by the side surface of the battery.

However, recently, the size of the control circuit board has been reduced, and a space has been left in the joint piece 4F. In order to increase the battery capacity, the batteries may be stacked. In this case, a plurality of small spaces defined by the joint pieces 4F are formed on the side surfaces of the battery stack, and the space is effectively used. It is difficult to plan.

[0010] The present invention solves the various problems described above,
An object of the present invention is to provide a battery and a battery pack in which the bulk of the battery is small and the extra space is easily used.

[0011]

In the battery according to the present invention (claim 1), a battery element is interposed between two exterior materials, and the outer edges of the exterior materials are joined to each other to seal the battery element. A battery, comprising: an encapsulating portion enclosing the battery element; and a joining piece portion formed by joining peripheral portions of the exterior material, and a terminal portion connected to the battery element is provided. In a battery that is drawn out through the mating surfaces of the outer packaging materials in the joint pieces along one side of the envelope, the joints along the one side are bent along the envelope. It is characterized by the following.

In the battery according to the present invention (claim 2), one package is folded back into two pieces, the battery element is interposed between these two pieces, and the periphery other than the folded side of the two pieces is provided. A battery in which the battery elements are hermetically sealed by joining the parts together, and has a covering part that covers the battery element, and a joining piece part in which peripheral parts of the exterior material are joined together. In a battery in which the terminal portion connected to the battery element is drawn out through the mating surface of the outer packaging materials in the joining piece portion along one side of the enclosing portion, the joining piece portion along the one side, preferably Is characterized in that all the joining pieces are bent along the envelope.

In the battery according to the present invention (claims 1 and 2), the joint piece from which the terminal portion is drawn out is bent so as to be along the envelope portion, and has a small bulk. Further, there is no small dead space which is difficult to use on the side surface of the enclosing portion.

According to the present invention, the battery can be made more compact and the housing itself can be made easier by forming a concave portion for housing the battery element in the exterior material.

In the present invention, the bent joint piece may be adhered to the encapsulating part by an adhesive. If you do this,
High strength and rigidity on the side of the battery. Of course, it is also prevented by this adhesion that the bent joint piece part separates from the encased part.

Further, when the joining piece is adhered to the encapsulating portion with an adhesive, the strength and rigidity of the side surface of the battery are high, so that even when the side surface is impacted, the active material may peel off. Is prevented. This adhesive is preferably a hot-melt adhesive.

In the present invention, the exterior material is preferably formed of a laminate of a synthetic resin layer and a metal layer. As a result, the exterior material can be made lighter.

A battery pack according to the present invention is characterized in that a plurality of the above batteries are stacked. As a result, the battery pack can be made smaller, or the space in the vicinity of the terminal can be used more effectively.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A battery according to an embodiment will be described below with reference to the drawings. 1 (a), 2 and 3 are perspective views showing a procedure for bending a joint piece of a battery according to an embodiment, and FIGS. 1 (b) and 1 (c) are BB in FIG. 1 (a). FIG. 8 is a cross-sectional view taken along line CC and line CC, and FIG.

In this battery, the battery element 1 is encapsulated by bending a series of integral exterior members 2 and 3 at one side 8 and joining the peripheral edges 2a and 3a of the exterior members 2 and 3 to form a joint piece 4A. ,
4F is bent, and the joining pieces 4A and 4F are adhered to the side surface of the enclosing part 4B with an adhesive 5. Joint pieces 4A, 4
F indicates a single piece in which the peripheral portions 2a and 3a are joined to each other. The enclosing portion 4B is a flat plate-shaped portion enclosing the battery element 1.

As shown in FIG. 7, the exterior material 2 is flat and
It has a lid shape that can be bent with respect to the exterior material 3.
The exterior material 3 is a shallow, open box-like shape having a housing portion 3b formed of a rectangular box-shaped recess and a peripheral portion 3a projecting outward in a flange shape from four peripheral edges of the housing portion 3b. The exterior materials 2 and 3 are integrally and continuously connected on one side 8,
Since the housing portion 3b starts from one side, no joining piece is formed on the side 8.

The battery element 1 is accommodated in the housing 3b of the exterior material 3.
Is accommodated, and the exterior material 2 is covered thereon. A pair of leads 21 extending from the battery element 1 are drawn out through the mating surfaces of the peripheral edges 2a, 3a on one side of the exterior materials 2, 3, respectively. Thereafter, the outer peripheral portions 2a, 3 of the four peripheral edges of the exterior materials 2, 3 are placed under a reduced pressure (preferably, vacuum) atmosphere.
a are hermetically joined by a method such as thermocompression bonding or ultrasonic welding, and the battery element 1 is sealed in the exterior materials 2 and 3.

The joining pieces 4A and 4F are formed by joining the peripheral edges 2a and 3a to each other. The joint pieces 4A and 4F project outward from the enclosing part 4B enclosing the battery element 1. Therefore, this joining piece portion 4A,
4F is entirely bent along the envelope portion 4B, and is adhered to the side surface of the envelope portion 4B with the adhesive 5.

When bending the joint piece, first, as shown in FIG.
The joint piece 4A is bent as shown in FIG. Next, the joining piece portion 4F is bent as shown in FIG. In this state, since the lead 21 extends in the surface direction of the joint piece 4F, the lead 21 is bent along the outer surface of the joint piece 4F as shown in FIG. Bend away from you.
In addition, as shown by a two-dot chain line 21 ′ in FIG.

Since the corner portion 4H protrudes in a triangular shape,
It may be bent so as to overlap the joining piece 4F, or may be cut and removed. However, when cut, moisture or air easily penetrates into the inside, so that it is preferably bent so as to overlap with the joining piece portion 4F.

In FIGS. 2 and 3, the corner portion 4H formed by bending the joining piece portion 4F extends outward, but as shown in the perspective views of FIGS.
This may be folded inside. That is, as shown in FIGS. 4 and 5, when the joining piece 4F is bent, the corner 4
H is made to exist between the encased portion 4B and the bent joint piece 4F, and then the lead 21 is bent along the outer surface of the joint piece 4F. Can be bent away. In this case, the lead 21
May be bent so as to overlap the enclosing portion 4B as shown by a two-dot chain line 21 'in FIG.

In general, adhesives are classified into thermosetting resin adhesives, thermoplastic resin adhesives, rubber-based adhesives (elastomers), and composite adhesives based on their thermodynamic properties. The present invention is classified into adhesives, emulsion adhesives, pressure-sensitive adhesives, rewetting adhesives (water-soluble adhesives), polycondensation-type solventless adhesives, film adhesives, and hot melt adhesives. Then, any of them may be used.
However, in the present invention, a hot melt adhesive is suitable as the adhesive.

Examples of the hot-melt adhesive include polyvinyl acetate, polymethyl methacrylate, polystyrene, polyvinyl alcohol, polyvinyl butyral, methyl cyanoacrylate, polysulfone, polyimide, polybenzimidazole, nylon, polyparaphenyl oxide, and the like. Polycarbonate, polyacetal,
Preferred are polyethylene, polypropylene, other ethylene-vinyl acetate copolymers, butadiene, copolymerized plastic polymers (ABS, high impact polystyrene), and the like. In addition, terpene resins, alfalt, rosin and derivatives thereof, ethyl cellulose, petroleum resins, and the like can also be used.

In FIG. 8, the exterior materials 2 and 3 are integrated in a series, but in the present invention, the exterior materials 2 and 3 may be separate as shown in FIG. In FIG. 7, the flat-plate-like exterior material 2 is covered on the open-box-shaped exterior material 3, and four peripheral edges 2 a and 3.
a.

In FIGS. 1 to 3, the joining pieces 4A and 4F are bent only once along the roots thereof. However, in the present invention, as shown in FIG. 1
It may be diffracted, and the tip of the joint piece 4A may be interposed between the joint piece 4A and the side surface of the enclosing part 4B. In this manner, intrusion of moisture or the like from the mating surfaces of the exterior materials 2 and 3 and the side surfaces of the exterior material from the tip of the joining piece portion 4A is more reliably prevented.

FIGS. 7 and 8 show the exterior material 3 having the accommodation portion 3b and the flat exterior material 2, but in the present invention, as shown in FIG. , 7b,
Peripheral portions 6a, 6a, which protrude from four peripheral edges of the housing portions 6b, 7b
The battery element 1 may be enveloped by the outer packaging materials 6 and 7 having the outer member 7a. In FIG. 9, the exterior materials 6 and 7 are integrated in a series, but they may be separate bodies as in FIG. 7.

FIG. 10 is a cross-sectional view of a battery in which the battery element 1 is wrapped by using the exterior members 6 and 7, and the peripheral portions 6a and 7
The joining piece portion 4C formed by joining the “a” is bent at the base thereof and is adhered to the side surface of the enclosing portion 4D enclosing the battery element 1 with the adhesive 5. In FIG. 10, the joining piece portion 4C is bent only at the base thereof, but may be bent twice as shown in FIG.

In the present invention, as shown in FIG. 12, one flat sheet-like exterior material 8 is folded in two along the central side 8a to form two pieces, a first piece 8A and a second piece 8B. Forming
The battery element 1 is interposed between the first piece 8A and the second piece 8B, and as shown in FIG. 13, the peripheral parts 8b of the first piece 8A and the second piece 8B are joined together to encapsulate the battery element 1. You may.

Also in this case, the leads 21 drawn outward from the mating surface of the exterior material are drawn outward from the side parallel to the central side 8a among the sides of the rectangular envelope. Although not shown, after that, the remaining one of the rectangular
In the parallel sides of the pair, a joint piece formed by joining the peripheral portions 8b is bent and adhered to the side surface of the enclosing portion with an adhesive.

In the battery of the present invention thus configured, the joining piece is bent along the envelope, and
Low bulk. Then, in a stacked body in which a plurality of the batteries are stacked, a small dead space does not occur along the stacked body.

In this embodiment, since the bent joint piece is adhered to the enclosing part by an adhesive, the strength and rigidity of the side surface of the battery are high. Of course, it is also prevented by this adhesion that the bent joint piece part separates from the encased part. In addition, the battery in which the bonding piece is bonded to the enclosing portion by this adhesive has high strength and rigidity on the side surface, so that even when a shock is applied to the side surface, peeling of the active material is prevented. .

Since the present invention is suitable as a thin-film battery, and particularly suitable for a lithium secondary battery, a preferred configuration when the above-mentioned battery element is a lithium secondary battery element will be described below. I do.

This lithium secondary battery is, as shown in FIG.
It has a positive electrode 11, a negative electrode 12, and an electrolyte layer 13 interposed therebetween.

As shown in FIG. 15, the positive electrode 11 or the negative electrode 12 usually has a current collector 15 as a core material and the positive electrode active material 11a or the negative electrode active material 12a
Are laminated.

As the current collector for the positive electrode, a metal foil such as aluminum, stainless steel, nickel or the like can be used. Particularly, aluminum is suitable. As the current collector for the negative electrode, a metal foil such as copper, stainless steel, nickel or the like can be used. Particularly, copper is preferred. The thickness of the current collector is preferably about 1 to 30 μm.

As the positive electrode active material, lithium ions are absorbed.
Use either inorganic or organic compounds if they can be stored and released.
Can be used. As inorganic compounds, transition metal oxides, lithium
Complex oxide of transition metal and transition metal, transition metal sulfide, specific
Contains MnO, V₂O₅, V ₆O1₁₃, TiO₂Etc.
Transition metal oxide, lithium nickelate, lithium cobaltate
And transition metals such as lithium and lithium manganate
Composite oxide, TiS ₂, FeS, MoS₂Transitions such as
Metal sulfide and the like. These compounds have properties
Which is partially elementally substituted to improve
Is also good. Examples of the organic compound include polyaniline and polyaniline.
Lipyrrole, polyacene, disulfide compound, poly
And sulfide compounds. The positive electrode active material
These inorganic compounds and organic compounds may be used as a mixture.
Particularly preferred are cobalt, nickel and manganese.
At least one transition metal selected from the group consisting of
It is a composite oxide with titanium.

The particle size of the positive electrode active material may be appropriately selected in accordance with the other components of the battery.
0 μm, especially 1 to 10 μm is preferable because battery characteristics such as initial efficiency and cycle characteristics are improved.

As the negative electrode active material, a carbon-based material such as graphite or coke is usually used. This carbon-based material may be used as a mixture with a metal, a metal salt, an oxide, or the like, or in the form of a coating. As the negative electrode active material, silicon, tin, zinc, manganese, iron, nickel and other oxides and sulfates, lithium metal, Li-Al, Li-Bi-Cd,
A lithium alloy such as Li-Sn-Cd, a lithium transition metal nitride, silicon and the like can also be used. Preferably, it is graphite or coke in terms of capacity. The average particle size of the negative electrode active material is usually 12 μm or less, preferably 10 μm or less, from the viewpoint of improving battery characteristics such as initial efficiency, late characteristics, and cycle characteristics. If the particle size is too large, the electron conductivity deteriorates. Also, usually 0.5 μm or more,
Preferably it is 7 μm or more.

It is preferable to use a binder for binding the positive electrode active material and the negative electrode active material on the current collector. As the binder, inorganic compounds such as silicate and glass, and various resins mainly composed of polymers can be used. Examples of the resin include alkane-based polymers such as polyethylene, polypropylene, and poly-1,1-dimethylethylene; unsaturated polymers such as polybutadiene and polyisoprene; polystyrene, polymethylstyrene, polyvinylpyridine, and poly-N-vinylpyrrolidone. Acrylic polymers such as polymethyl methacrylate, polyethyl methacrylate, polybutyl methacrylate, polymethyl acrylate, polyethyl acrylate, polyacrylic acid, polymethacrylic acid, polyacrylamide; polyfluorinated vinyl,
Fluorinated resins such as polyvinylidene fluoride and polytetrafluoroethylene; CN group-containing polymers such as polyacrylonitrile and polyvinylidene cyanide; polyvinyl alcohol-based polymers such as polyvinyl acetate and polyvinyl alcohol; polyvinyl chloride and polyvinylidene chloride Halogen-containing polymers; conductive polymers such as polyaniline can be used. Further, a mixture of the above-mentioned polymers and the like, a modified product, a derivative, a random copolymer, an alternating copolymer, a graft copolymer, a block copolymer and the like can be used.

The amount of the binder is preferably 0.1 to 30 parts by weight, more preferably 1 to 15 parts by weight, based on 100 parts by weight of the active material. If the amount of the resin is too small, the strength of the electrode may decrease. If the amount of the resin is too small, the capacity may decrease, or the late characteristics may decrease.

The positive electrode active material and the negative electrode active material may contain additives, such as conductive materials and reinforcing materials, exhibiting various functions, powders, fillers, and the like, if necessary.

The conductive material is not particularly limited as long as it can impart conductivity by mixing an appropriate amount with the above-mentioned active material. Usually, carbon powder such as acetylene black, carbon black and graphite, and various metals are used. Fibers, foils and the like can be mentioned. Additives include trifluoropropylene carbonate, vinylene carbonate, 1,6-Di
oxaspiro [4,4] nonane-2,7-d
ion, 12-crown-4-ether and the like can be used to increase the stability and life of the battery. As the reinforcing material, various inorganic and organic spherical and fibrous fillers can be used.

As a method of forming an electrode on a current collector,
For example, a method of mixing a powdered active material with a solvent together with a binder, dispersing the active material with a ball mill, a sand mill, a twin-screw kneader, or the like, coating the resultant on a current collector, and drying the resultant is preferably performed. In this case, the kind of the solvent used is not particularly limited as long as it is inert to the electrode material and can dissolve the binder. For example, any of commonly used inorganic and organic solvents such as N-methylpyrrolidone and the like can be used. Can also be used.

Further, the electrode material layer may be formed by a method of pressing or spraying the active material on a current collector in a state of being softened by mixing and heating the active material with a binder. Furthermore, it can be formed by firing the active material alone on the current collector.

An ion mobile phase is usually formed in the positive electrode and the negative electrode. The proportion of the ion mobile phase in the electrode is
The higher the value, the easier the ion migration becomes. The preferable is the rate characteristic, while the lower the value, the higher the capacitance. Preferably 1
0 to 50% by volume. As materials for the ion mobile phase,
The same material as the electrolyte phase material described later can be used.

It is preferable that the positive electrode active material and the negative electrode active material be thicker in terms of capacity and thinner on the rate. The film thickness is usually at least 20 μm, preferably at least 30 μm, more preferably at least 50 μm, most preferably at least 80 μm. The thickness of the positive electrode and the negative electrode is usually 200 μm or less, preferably 150 μm or less.

As shown in FIG. 14, the positive electrode 11 and the negative electrode 12
An electrolyte layer 13 is formed between them. Electrolyte layer 13
Usually includes various electrolytes such as an electrolyte having fluidity and a non-fluid electrolyte such as a gel electrolyte and a completely solid electrolyte. An electrolyte or a gel electrolyte is preferable in terms of battery characteristics, and a non-fluid electrolyte is preferable in terms of safety. In particular,
When a non-fluid electrolyte is used, liquid leakage can be more effectively prevented with respect to a battery using a conventional electrolyte, so that the advantage of using a case having a shape changeability such as a laminate film described later is maximized. You can make use of it.

The electrolyte used for the electrolyte layer is usually a solution obtained by dissolving a supporting electrolyte in a non-aqueous solvent.

As a supporting electrolyte, a non-aqueous substance which is stable as an electrolyte with respect to the positive electrode active material and the negative electrode active material, and which can undergo a lithium ion to undergo an electrochemical reaction with the positive electrode active material or the negative electrode active material. Any of them can be used. Specifically, LiPF
_{6, LiAsF 6, LiSbF 6,} LiBF 4, LiC
10 ₄ , LiI, LiBr, LiCl, LiAlCl,
Lithium salts such as LiHF ₂ , LiSCN, and LiSO ₃ CF ₂ are mentioned. Of these, LiPF ₆ ,
LiClO ₄ is preferred.

When these supporting electrolytes are used in the state of being dissolved in a non-aqueous solvent, the concentration is 0.5 to 2.5 mol / L.
Is preferred. The nonaqueous solvent in which these supporting electrolytes are dissolved is not particularly limited, but a solvent having a relatively high dielectric constant is preferably used. Specifically, acyclic carbonates such as ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate; glymes such as tetrahydrofuran, 2-methyltetrahydrofuran, and dimethoxyethane;
One or more of lactones such as -butyllactone, sulfur compounds such as sulfolane, and nitriles such as acetonitrile are exemplified.

Among these, one or more solvents selected from cyclic carbonates such as ethylene carbonate and propylene carbonate, and acyclic carbonates such as dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate are particularly preferred. is there. Further, additives and the like may be added to these solvents. Examples of the additive include trifluoropropylene carbonate, vinylene carbonate, 1,6-dioxaspi
ro [4,4] nonane-2,7-dione, 1
2-crown-4-ether and the like can be used for the purpose of increasing the stability and life of the battery.

The gel electrolyte which can be used for the electrolyte layer is usually obtained by holding the above-mentioned electrolyte solution with a polymer. That is,
The gel electrolyte is one in which the electrolyte is generally held in a polymer network, and the fluidity as a whole is significantly reduced. Such a gel electrolyte exhibits properties such as ionic conductivity that are close to those of a normal electrolyte solution, but fluidity, volatility and the like are significantly suppressed, and safety is enhanced. The ratio of the polymer in the gel electrolyte is preferably 1 to 50% by weight. If the temperature is too low, the electrolyte cannot be held, and a liquid leak may occur. If it is too high, the ionic conductivity tends to decrease and battery characteristics tend to deteriorate.

As the polymer used for the gel electrolyte,
There is no particular limitation as long as it is a polymer that can form a gel together with the electrolyte, and polyester, polyamide, polycarbonate, those produced by polycondensation such as polyimide,
Polyurethane, polyurea, etc. produced by polyaddition, acrylic derivative polymers such as polymethyl methacrylate, and polyadditions produced by polyvinyl polymerization such as polyvinyl acetate, polyvinyl chloride, polyvinylidene fluoride, etc. and so on. Preferred polymers include polyacrylonitrile and polyvinylidene fluoride. Here, the polyvinylidene fluoride includes not only a homopolymer of vinylidene fluoride but also a copolymer with another monomer component such as hexafluoropropylene. Also, acrylic acid, methyl acrylate,
Ethyl acrylate, ethoxyethyl acrylate, methoxyethyl acrylate, ethoxyethoxyethyl acrylate, polyethylene glycol monoacrylate,
Ethoxyethyl methacrylate, methoxyethyl methacrylate, ethoxyethoxyethyl methacrylate, polyethylene glycol monomethacrylate, N, N-diethylaminoethyl acrylate, N, N-dimethylaminoethyl acrylate, glycidyl acrylate, allyl acrylate, acrylonitrile, N-vinylpyrrolidone, diethylene glycol di Acrylic obtained by polymerizing acrylic monomers such as acrylate, triethylene glycol diacrylate, tetraethylene glycol acrylate, polyethylene glycol diacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, and polyethylene glycol dimethacrylate. Can be used polymers are also preferred.

The weight average molecular weight of the above polymer is usually 10
000 to 5,000,000. If the molecular weight is low, it is difficult to form a gel. If the molecular weight is high, the viscosity becomes too high and handling becomes difficult. The concentration of the polymer with respect to the electrolytic solution may be appropriately selected according to the molecular weight, but is preferably 0.1 to 30% by weight. If the concentration is too low, it is difficult to form a gel, the retention of the electrolytic solution is reduced, and problems of flow and liquid leakage may occur. If the concentration is too high, the viscosity becomes too high, which causes difficulties in the process, and the proportion of the electrolytic solution is reduced, the ionic conductivity is reduced, and the battery characteristics such as late characteristics may be deteriorated.

A completely solid electrolyte layer can be used as the electrolyte layer. As such a solid electrolyte, various solid electrolytes known so far can be used. For example, it can be formed by mixing the polymer used in the gel electrolyte and the supporting electrolyte salt at an appropriate ratio. In this case, in order to increase the conductivity, it is preferable to use a polymer having a high polarity and to have a skeleton having many side chains.

As the electrolyte layer, a material obtained by impregnating a porous sheet such as a porous membrane with the above electrolyte may be used.

The thickness of the electrolyte layer is usually 1 to 200 μm,
Preferably, it is 5 to 100 μm.

As the porous sheet, specifically, the thickness is usually 1 μm or more, preferably 5 μm or more, and usually 200 μm or more.
μm or less, preferably 100 μm or less is used. The porosity is usually 10 to 95%, preferably 30 to 8%.
It is about 5%. As a material of the porous sheet, a polyolefin or a polyolefin in which part or all of hydrogen atoms have been substituted with fluorine can be used. Specifically, a microporous film, a nonwoven fabric, a woven fabric, or the like formed using a synthetic resin such as polyolefin can be used.

A battery element is obtained by laminating a positive electrode and a negative electrode via an electrolyte layer. The battery element may have a flat plate shape by laminating a positive electrode, a negative electrode, and an electrolyte layer in a thickness direction, or may have a substantially cylindrical shape or a flat cylindrical shape by laminating it after lamination.

For example, as shown in FIG.
The positive electrode composition is laminated on both surfaces of the positive electrode 11 to obtain a plate-shaped positive electrode 11.
The negative electrode material 12 is formed in a plate shape by the same method, and the positive electrode 11 and the negative electrode 12 formed in the plate shape are, as shown in FIG.
The layers are alternately stacked via the electrolyte layer 13. FIG.
Can be stacked in the direction in which the positive electrode 11 side or the negative electrode 12 side is in contact with each other, such as the battery element shown in FIG. Such a configuration is particularly effective when a positive electrode or a negative electrode is formed on one surface of the current collector.

In both cases of FIGS. 14 and 17, the battery has a structure in which a plurality of flat battery elements are stacked in the thickness direction.

The planar shape of the electrode is arbitrary, and may be square, circular, polygonal, or the like.

As shown in FIGS. 14 to 18, the current collector 15 is usually provided with tabs 4a and 4b for lead connection. When the electrode is rectangular, a tab 4a projecting from the current collector 5 of the positive electrode 1 is usually formed near one side of one side of the electrode as shown in FIG. A tab 4b is formed near the side.

It is effective to stack a plurality of battery elements in order to increase the capacity of the battery. At this time, however, the tabs 4a and 4b from each of the battery elements usually have a structure shown in FIG.
The positive and negative electrode lead connection terminals are formed by being joined in the thickness direction as shown in FIG. As a result, a large-capacity battery element 1 can be obtained.

As shown in FIG. 18, a lead 21 made of a flaky metal is connected to the tabs 4a and 4b. As a result, the lead 21 and the positive electrode 11 and the negative electrode 12 are electrically coupled. Connection between tabs 4a, 4b and tab 4
The connection between the leads a and 4b and the lead 21 can be performed by resistance welding such as spot welding, ultrasonic welding or laser welding.

In the present invention, it is preferable to use an annealed metal as at least one of the positive electrode lead and the negative electrode lead 21 and preferably both of the leads. As a result, a battery having excellent bending durability as well as strength can be obtained.

As the kind of metal used for the lead, aluminum, copper, nickel, SUS or the like can be generally used. The preferred material for the positive electrode lead is aluminum. A preferable material for the lead of the negative electrode is copper.

The thickness of the lead 21 is usually at least 1 μm, preferably at least 10 μm, more preferably at least 20 μm.
Most preferably, it is 40 μm or more. If the thickness is too small, the mechanical strength of the lead such as tensile strength tends to be insufficient. The thickness of the lead is usually 1000 μm or less, preferably 500 μm or less, and more preferably 100 μm or less. If the thickness is too large, the bending durability tends to deteriorate, and the case tends to be difficult to seal the battery element. The advantage of using the later-described annealed metal for the lead is more remarkable as the thickness of the lead is larger.

The width of the lead is usually 1 mm or more and 20 mm or less, particularly about 1 mm or more and 10 mm or less, and the length of the lead exposed to the outside is usually about 1 mm or more and 50 mm or less.

It is preferable that the exterior members 2, 3, 6, and 7 have shape variability. As a result, it is possible to easily change the shape of the battery in various ways. Further, after the interior of the exterior material is evacuated, by sealing the peripheral portion of the exterior material, a pressing force can be applied to the battery element 1, and as a result, battery characteristics such as cycle characteristics are improved. be able to.

As a material of the exterior material, a metal such as aluminum or nickel-plated iron or copper, a synthetic resin, or the like can be used. Preferably, a laminated composite material in which a metal and a synthetic resin are laminated is used. Can be By using this laminated composite material, the thickness and weight of the case member can be reduced, and the capacity of the battery as a whole can be improved.

FIG. 19 shows a laminated composite material.
As shown in (A), a laminate in which a metal layer 40 and a synthetic resin layer 41 are laminated can be used. This metal layer 40
Is for preventing infiltration of water or maintaining shape retention, and may be a simple metal such as aluminum, iron, copper, nickel, titanium, molybdenum, gold, or an alloy such as stainless steel, Hastelloy, or a metal oxide such as aluminum oxide. . Particularly, aluminum having excellent workability is preferable.

The formation of the metal layer 40 can be performed using a metal foil, a metal deposition film, a metal sputter, or the like.

The synthetic resin layer 41 is used to protect the case member, prevent invasion by the electrolyte, prevent contact between the metal layer and the battery element, or protect the metal layer. In the present invention, the elastic modulus and the tensile elongation of the synthetic resin are not limited. Therefore, the synthetic resin in the present invention includes what is generally called an elastomer.

As the synthetic resin, thermoplastics, thermoplastic elastomers, thermosetting resins, and plastic alloys are used. These resins include those in which a filler such as a filler is mixed.

The laminated composite material is shown in FIG.
As shown in (B), a synthetic resin layer 41 for functioning as an outer protective layer is provided on the outer surface of the metal layer 40, and corrosion on the inner surface and contact between the metal layer and the battery element are prevented on the inner surface. A three-layer structure in which the synthetic resin layers 42 functioning as inner protective layers for protecting the layers can be formed.

In this case, the resin used for the outer protective layer is
Preferably, resins excellent in chemical resistance and mechanical strength, such as polyethylene, polypropylene, modified polyolefin, ionomer, amorphous polyolefin, polyethylene terephthalate, and polyamide are desirable.

As the inner protective layer, a synthetic resin having chemical resistance is used. For example, polyethylene, polypropylene, modified polyolefin, ionomer, ethylene-vinyl acetate copolymer and the like can be used.

Further, as shown in FIG. 20, the composite material may be provided with an adhesive layer 43 between the metal layer 40, the synthetic resin layer 41 for forming the protective layer, and the synthetic resin layer 42 for forming the corrosion-resistant layer. Furthermore, in order to adhere the case members to each other,
An adhesive layer made of a resin such as polyethylene or polypropylene that can be welded can be provided on the innermost surface of the composite material. A case is formed using these metals, synthetic resins or composite materials. The case may be formed by fusing the periphery of the film-like body, or the sheet-like body may be drawn by vacuum forming, pressure forming, press forming or the like. Also,
It can also be molded by injection molding a synthetic resin. When injection molding is used, the metal layer is usually formed by sputtering or the like.

In order to provide a housing portion formed of a concave portion on the exterior material, drawing can be performed.

In the case where a battery is formed by using such an exterior material made of a composite material, it is preferable that the surface in contact with the adhesive 5 be a synthetic resin layer. By doing so, the adhesive strength between the adhesive and the exterior material can be increased. In addition, it adheres easily even in a dry room when a non-aqueous battery is manufactured.

The battery pack of the present invention, as shown in FIG.
A plurality of such batteries 211 are stacked. FIG.
In this battery pack, four batteries 211 are laminated in the thickness direction (the direction of lamination of two or two pieces of the exterior material), and the leads 21 of each battery are aligned in the same direction. The battery 211 is housed in a rigid resin case 212. Although a part of the case 212 (in the vicinity of the lead 21) is cut away for convenience of description, in an actual example, the entire battery 211 is housed.

As shown in FIG. 21, the battery pack of the present invention
Since the joining piece portion 4F is bent along the envelope portion of the exterior material, a large space 213 can be formed in the vicinity of the terminal portion of the battery when these are laminated. It can be used effectively. For example, FIG.
As in 1, the printed wiring board 214 can be provided in the space 213. Further, since the joining piece portion 4F is bent along the encased portion of the exterior material, the pack can be made more compact when these are stacked and stored in a case.

In the present invention, the “battery pack”
Does not necessarily mean only the state where the battery is further housed in the case as shown in FIG. 21, for example,
Electronic devices such as mobile phones and personal computers on which batteries are directly stacked are also included in the “battery pack”.

[0090]

As described above, in the battery of the present invention, all the joining pieces or the overhanging pieces are bent so as to be along the enclosing part, and the bulk is small. When this battery is stacked,
A plurality of small dead spaces do not occur along the stack, and the size of an electronic device (for example, a mobile phone) incorporating the battery stack can be reduced.

[Brief description of the drawings]

1A is a perspective view showing a procedure for bending a joint piece of a battery according to an embodiment, and FIGS. 1B and 1C are views taken along line BB and CC in FIG. 1A. It is sectional drawing which follows a line.

FIG. 2 is a perspective view showing a procedure for bending a joint piece of the battery according to the embodiment.

FIG. 3 is a perspective view showing a procedure of bending a joint piece of the battery according to the embodiment.

FIG. 4 is a perspective view showing a procedure for bending a joint piece of a battery according to another embodiment.

FIG. 5 is a perspective view showing a procedure of bending a joint piece of the battery according to the embodiment of FIG. 4;

FIG. 6 (a) is a perspective view showing a procedure of bending a joint piece of a battery according to a conventional example, and FIGS. 6 (b) and (c) are views taken along line B- of FIG.
It is sectional drawing which follows the B line and CC line.

FIG. 7 is a perspective view of exterior materials 2 and 3;

FIG. 8 is a perspective view showing another configuration example of the exterior materials 2 and 3.

FIG. 9 is a perspective view showing a configuration example of exterior materials 6 and 7;

FIG. 10 is a cross-sectional view of a battery according to another embodiment.

FIG. 11 is a cross-sectional view of a battery according to another embodiment.

FIG. 12 is a perspective view showing a configuration example of an exterior material 8;

FIG. 13 is a plan view of a battery using the exterior material of FIG. 12 in the process of being manufactured.

FIG. 14 is a schematic sectional view of a battery element.

FIG. 15 is a schematic sectional view of a positive electrode or a negative electrode.

FIG. 16 is a perspective view showing a configuration of a terminal portion of a battery element.

FIG. 17 is a cross-sectional view showing another configuration example of the battery element.

FIG. 18 is a longitudinal sectional view showing a relationship between tabs and leads of a plurality of battery elements.

FIGS. 19A and 19B are longitudinal sectional views each showing an example of a composite material constituting an exterior material.

FIG. 20 is a longitudinal sectional view showing another example of the composite material forming the exterior material.

FIG. 21 is an exploded perspective view showing a configuration of a battery pack.

[Description of Signs] 1 Battery element 2, 3, 6, 7, 8 Exterior material 4a, 4b Tab 4A, 4C Joint 4B, 4D Enclosure 5 Adhesive 11 Positive electrode 11a Positive electrode active material 12 Negative electrode 12b Negative electrode active material 13 Non-fluid electrolyte layer 15 Current collector 21 Lead 40 Metal layer 41, 42 Synthetic resin layer 43 Adhesive layer 211 Battery 214 Printed wiring board

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H011 DD06 DD14 5H028 BB04 BB05 CC02 5H029 AJ00 BJ04 CJ03 CJ05 DJ02 5H040 AA01 AT04 AY06 AY08 JJ02 JJ03

Claims (7)

[Claims] 1. A battery element is interposed between two exterior materials,
A battery in which battery elements are hermetically sealed by joining peripheral parts of the exterior material, and a joining piece formed by joining a surrounding part of the battery element and a peripheral part of the exterior material. Wherein the terminal portion connected to the battery element is drawn out through the mating surface of the exterior materials in the joint piece portion along one side of the enclosing portion, wherein the terminal portion extends along the one side. A battery wherein a joint piece is bent along the envelope. 2. An outer package is folded back into two pieces, a battery element is interposed between these two pieces, and peripheral parts other than the folded sides of the two pieces are joined to seal the battery element. A battery comprising: an encapsulating portion enclosing the battery element; and a joining piece portion formed by joining peripheral portions of the exterior material, and a terminal portion connected to the battery element is provided. In a battery that is drawn out through the mating surfaces of the outer packaging materials in the joint pieces along one side of the envelope, the joints along the one side are bent along the envelope. A battery. 3. The battery according to claim 2, wherein all the joint pieces are bent along the envelope. 4. The battery according to claim 1, wherein a recess for accommodating the battery element is formed in the exterior material in advance. 5. The battery according to claim 1, wherein a portion bent along the envelope portion is adhered to the envelope portion with an adhesive. 6. The battery according to claim 1, wherein the exterior material is formed of a laminate of a synthetic resin layer and a metal layer. 7. A battery pack comprising a plurality of the batteries according to claim 1 stacked.