JP2003086170A - Lead parts - Google Patents

Abstract

(57) [Summary] (Problem corrected) [PROBLEMS] A lead component and a lead component capable of using a sealing material without increasing the number of battery assembly steps and preventing displacement of the sealing material during battery assembly. Provision of manufacturing method. SOLUTION: A pair of a lead for a positive electrode, a lead for a negative electrode, and a sealing material 106, and a sealing material is provided on both surfaces of the positive electrode lead and the negative electrode lead so as to straddle the positive electrode lead and the negative electrode lead. A lead component provided with a positive electrode lead, a negative electrode lead, and a sealing material. In the battery of the present invention, the battery element 1 is accommodated in the accommodating portion 3b of the exterior material 3, and the exterior material 2 is covered. 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 four peripheral edges 2a, 3a of the outer packaging materials 2, 3 are hermetically joined to each other in a reduced pressure atmosphere by a method such as thermocompression bonding or ultrasonic welding, and the battery element 1 is attached to the outer packaging materials 2, 3
Enclosed in

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead component, and more particularly to a lead component including a positive electrode lead, a negative electrode lead and a sealing material, and a battery using the lead component and a lead component. It relates to a manufacturing method.

[0002]

2. Description of the Related Art In recent years, due to demands for thinner batteries, lighter batteries, etc., a battery element (for example, a power generating element composed of a laminated body of a positive electrode, a separator and a negative electrode) as described in JP-A-8-83596 is provided. Batteries coated with a laminate film have been developed. In such a battery, displacement is prevented by bringing the laminate into close contact and applying external pressure. In the battery, it is necessary to pass metal leads, which are electrically coupled to the positive electrode and the negative electrode, independently of each other, through the sealing portion of the outer packaging material to be exposed to the outside of the outer packaging material. The outer material sealing portion was not sufficiently sealed, and there was a possibility that the battery performance might be deteriorated due to the intrusion of water. Therefore, it is considered that the encapsulating material is sandwiched between the lead and the outer packaging material, but enclosing the encapsulating material has a problem that the number of battery assembly steps is increased and the manufacturing process is complicated. In addition, the position of the sealing material may be displaced during battery assembly, resulting in insufficient sealing.

[0003]

Therefore, there has been a demand for a means capable of using the sealing material without increasing the number of steps for assembling the battery and preventing the displacement of the sealing material during the battery assembly. .

[0004]

Means for Solving the Problems The inventors of the present invention have made extensive studies to solve the above-mentioned problems, and as a result, have found that the above-mentioned problems can be solved by integrating a lead with a sealing material in advance, and the present invention is completed. Came to do. That is, the gist of the present invention lies in the following (1) to (9). (1) A positive electrode lead, a negative electrode lead, and a sealing material. A sealing material is provided on both surfaces of the positive electrode lead and the negative electrode lead so as to straddle the positive electrode lead and the negative electrode lead. A lead component in which the negative electrode lead and the sealing material are integrated.

(2) For the positive electrode lead and the negative electrode lead,
The lead component according to (1) above, wherein the sealing material is joined by heat fusion or ultrasonic fusion. (3) The lead component according to the above (1) or (2), wherein a primer is applied to the sealing material joints of the positive electrode lead and the negative electrode lead. (4) The lead component according to any one of (1) to (3) above, wherein the positive electrode lead is made of aluminum and the negative electrode lead is made of copper.

(5) The lead component according to any one of (1) to (4) above, wherein the ends of the sides of the lead in the longitudinal direction are curved surfaces. (6) The lead component according to any one of (1) to (5) above, wherein the encapsulating material is made of a polyolefin resin having a polar group. (7) The thickness a of the lead and the thickness b of the sealing material are

[0007]

The lead component according to any one of the above (1) to (6), wherein b> a / 2 is satisfied. (8) A battery in which a battery element is interposed between exterior materials, and peripheral portions of the exterior material are sealed to each other to seal the battery element, the exterior material having resin layers on both sides of a gas barrier layer. A battery having a metal lead that is electrically coupled to each of the positive electrode and the negative electrode independently of each other, and the lead penetrates the sealing portion of the outer package to the outside of the outer package. A battery using the lead component according to any one of (1) to (7) above.

(9) A strip-shaped positive electrode lead and a strip-shaped negative electrode lead are arranged in parallel, and sealed on both sides of the positive electrode lead and the negative electrode lead so as to straddle the polar lead and the negative electrode lead at regular intervals. Place the material, then heat or ultrasonic fusion,
A method of manufacturing a lead component, which comprises cutting the lead at regular intervals.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The lead component of the present invention comprises a positive electrode lead, a negative electrode lead and a sealing material. As shown in FIGS. 12 and 13, a positive electrode lead 21 and a negative electrode lead 2 are provided.
A sealing material 106 is provided on both surfaces of No. 1 so as to straddle the positive electrode lead and the negative electrode lead, and the positive electrode lead, the negative electrode lead, and the sealing material are integrated (in FIGS. 12 and 13, the leads are shown. 21 is a positive electrode lead and the other is a negative electrode lead). By integrating the positive electrode lead, the negative electrode lead, and the encapsulant in advance, it is possible to use the encapsulant without increasing the number of steps for assembling the battery, and the displacement of the encapsulant during the battery assembly. Can be prevented.

The lead parts in the present invention are as shown in FIG.
It means a component including a positive electrode lead, a negative electrode lead and a sealing material as shown in Nos. 2 and 13. In the present invention,
It is preferable to use an annealed metal as at least one of the lead 21 for the positive electrode and the lead 21 for the negative electrode, and preferably for both of the leads 21. As a result, not only the strength but also the bending durability can be made excellent.

Generally, aluminum, copper, nickel, SUS or the like can be used as the kind of metal used for the leads. The preferred material for the positive electrode lead is aluminum. The preferred material for the negative electrode lead is copper or nickel, and particularly preferred is copper. The thickness of the lead 21 is usually 1 μm or more, preferably 10 μm
Or more, more preferably 20 μm or more, and most preferably 4 μm or more.
It is 0 μm or more. If it is too thin, 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, more preferably 100 μm or less. If it is too thick, the bending durability tends to deteriorate, and sealing of the battery element by the case tends to become difficult. The advantage of using the annealed metal described below for the lead is more remarkable as the lead is thicker.

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 exposed length of the lead to the outside (the outside of the exterior material during battery assembly) is usually 1
It is about mm to 50 mm. From the viewpoint of increasing the adhesive strength between the lead and the sealing material, it is preferable that the end portion of the side of the lead in the longitudinal direction is a curved surface, as shown in FIG. The side in the longitudinal direction of the lead is C in FIG.
Means

As the material of the sealing material in the present invention, a film made of synthetic resin can be mentioned. Examples of the material include those obtained by modifying a synthetic resin with an acid. Particularly, from the viewpoint of adhesiveness with the outer casing, the same synthetic resin as the synthetic resin forming the inner protective layer of the outer casing of the battery is treated with an acid. The modified one is preferable. The acid modified product of the synthetic resin is a synthetic resin having a polar group introduced by acid treatment. Specifically, a polyolefin-based resin acid-modified product having a polar group may be mentioned.

Examples of the polar group in the present invention include a carboxyl group, an acid anhydride group, a hydroxyl group, a phosphoric acid group, a phosphorous acid group, a sulfuric acid group, a sulfite group, an amino group, a cyano group and a nitro group, and preferably a carboxyl group. And an acid anhydride group.
The method for producing an acid-modified synthetic resin can be obtained, for example, by graft-polymerizing an α, β-unsaturated carboxylic acid or an anhydride thereof with a polyolefin resin as a raw material in the presence of a radical initiator.

As the graft polymerization method, a method of melt-kneading a polyolefin resin, an α, β unsaturated carboxylic acid or an anhydride thereof, and a radical initiator by using an extruder to perform radical polymerization, or a radical polymerization initiation with a polyolefin resin The agent is dissolved in an aromatic hydrocarbon solvent such as toluene, xylene, chlorobenzene or benzene, and α, β-
A method in which an unsaturated carboxylic acid or an anhydride thereof is added and radical polymerization is performed under heating is included.

As the α, β-unsaturated carboxylic acid or its anhydride, acrylic acid, methacrylic acid, maleic acid, itaconic acid, citraconic acid, crotonic acid, fumaric acid, maleic anhydride or the like is usually used. Further, in a polybasic acid such as maleic acid or fumaric acid, its half alkyl ester may be used. These α, β-unsaturated carboxylic acids or their anhydrides may be used in combination with other vinyl-based monomers such as acrylonitrile, acrylamide, vinyl chloride and 2-hydroxyacrylate.

The polyolefin resin having a polar group, which is a graft polymer obtained by such radical polymerization, contains unreacted α, β-unsaturated carboxylic acid or its anhydride, so that it is added to acetone or the like. It is preferable to remove it by repeating reprecipitation and washing. After washing, the residual solvent is usually removed by vacuum drying or the like.
The radical polymerization initiator may be any of those generally known,
Examples thereof include organic peroxides such as alkyl peroxides, aryl peroxides, acyl peroxides, aroyl peroxides, ketone peroxides, peroxycarbonates and peroxycarboxylates, and azonitriles. Alkyl peroxides include diisopropyl peroxide, di-tert-butyl peroxide, tert-butyl hydroperoxide, etc., aryl peroxides such as dicumyl peroxide, cumyl hydroperoxide, etc., and acyl peroxides such as dilauroyl. Examples thereof include dibenzoyl peroxide and the like as aroyl peroxide, methyl ethyl ketone peroxide and cyclohexane peroxide and the like as ketone peroxide, and azobisisobutyronitrile, azobisisopropionitrile and the like as azonitrile.

The number average molecular weight of the polyolefin resin having a polar group thus obtained is usually 5,000 to 5,000.
500000, preferably 10,000-200000,
More preferably, it is 20,000 to 100,000. Further, the polyolefin resin having a polar group is α, β-
The unsaturated carboxylic acid or its anhydride is usually added in an amount of 0.1 to 5
The content is 0% by weight, preferably 0.5 to 30% by weight, more preferably 1 to 10% by weight.

From the viewpoint of sealing strength, the sealing material is arranged on both sides of the lead. Positive electrode lead and negative electrode lead,
Examples of the method of joining with the sealing material include the use of an adhesive, joining by fusion, and the like, but from the viewpoint of adhesive strength, joining by heat fusion or ultrasonic fusion is preferable. In addition,
From the viewpoint of the adhesive strength between the lead and the sealing material, the lead thickness a
And the thickness b of the sealing material are

[0020]

It is preferable that b> a / 2 is satisfied. The thickness of the lead is as described above, and the thickness of the sealing material may be determined within the above range according to the thickness of any lead. The thickness of the encapsulant is more preferably 10 to 1000 μm, more preferably 10
˜100 μm.

Further, in the present invention, from the viewpoint of increasing the adhesive strength between the lead and the encapsulant, it is preferable that a primer is applied to the encapsulant joint between the positive electrode lead and the negative electrode lead. When the lead is coated with a primer, a synthetic resin is generally suspended or dissolved in an organic solvent before use. The organic solvent used is usually an aromatic hydrocarbon such as toluene, xylene or chlorobenzene, tetralin,
Aliphatic hydrocarbons such as mineral spirits and acetone,
Methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, diisobutyl ketone, ketones such as isophorone, ethyl acetate, butyl acetate, esters such as cellosolve acetate, other methylene chloride, tetrahydrofuran,
A mixed solvent with dimethylformamide or the like is used.

The amount of the organic solvent added is determined by the ease with which the solution is applied to the leads, but the content of the synthetic resin in the mixed solvent of the organic solvent and the synthetic resin is usually 0.5-50.
The amount is such that the weight percentage is preferably 2 to 30 wt%. The synthetic resin used as the primer is required to have both adhesiveness to the lead and adhesiveness to the encapsulant, and a synthetic resin having a polar group is preferable. Examples of the synthetic resin having a polar group include the same as those mentioned for the encapsulating material, preferably an acid modified product of a synthetic resin constituting the inner protective layer of the exterior material, more preferably a polyolefin resin. It was treated with an acid having a polar group. Examples of the acid having a polar group are the same as those listed for the encapsulating material, and preferably a carboxyl group and an acid anhydride group. The synthetic resin used as the primer (hereinafter referred to as “primer resin”) may be the same synthetic resin as the sealing material. Even if the encapsulating material and the coating resin are the same, higher adhesion between the lead and the primer resin can be maintained by applying synthetic resin (primer) to the lead in advance.

The polar group-containing synthetic resin can be obtained in the same manner as in the method for producing the acid-modified synthetic resin described in the section of the sealing material. The lead component of the present invention is shown in FIG.
As shown in, the strip-shaped positive electrode lead and the strip-shaped negative electrode lead are arranged in parallel, and the sealing material is provided on both sides of the positive electrode lead and the negative electrode lead so as to straddle the positive electrode lead and the negative electrode lead at regular intervals. Can be manufactured by arranging the above, then bonding the encapsulant to the positive electrode lead and the negative electrode lead, and cutting the leads at regular intervals. The method of joining the positive electrode lead, the negative electrode lead, the encapsulant, the positive electrode lead and the negative electrode lead with the encapsulant is the same as described in the description of the lead component.

Further, from the viewpoint of increasing the adhesive strength between the lead and the encapsulant, before joining the encapsulant to the positive electrode lead and the negative electrode lead, the encapsulant joint portion of the positive electrode lead and the negative electrode lead is joined. It is preferable to apply a primer. The same applies to the primer as described in the description of the lead component. The present invention also includes a battery using the above lead component. Specifically, the battery element is interposed between the exterior materials, the peripheral edges of the exterior material are sealed to seal the battery element, and the exterior material has a resin layer on both sides of the gas barrier layer. The exterior material is provided, and has metal leads that are electrically coupled to the positive electrode and the negative electrode independently of each other, and the leads penetrate the sealing portion of the exterior material and are exposed to the outside of the exterior material. In the present battery, the lead component of the present invention described above is used.

The battery of the present invention will be described in detail below with reference to the drawings. The present invention, as shown in FIGS.
Is interposed between the exterior materials 2 and 3, and the peripheral portion 2a of the exterior material,
3a is a battery in which battery elements are hermetically sealed and the battery element is hermetically sealed, and the exterior material is an exterior material in which a resin layer is provided on both surfaces of a gas barrier layer, and the electricity is provided independently of each of the positive electrode and the negative electrode. The present invention relates to a battery having a metallic lead 21 that is electrically coupled and that the lead penetrates a sealed portion of the exterior material and is exposed to the outside of the exterior material.

In the present invention, the exterior material has an inner protective layer made of synthetic resin, and the sealing material 106 made of synthetic resin is interposed in the sealing portion of the exterior material through which the lead penetrates.
It is essential that the encapsulating material is arranged on both sides of the lead 21. It is preferable that the portion of the lead penetrating the sealing portion of the exterior material is coated with a synthetic resin having a polar group (101 in FIG. 2).

A preferred embodiment of the battery of the present invention will be described below with reference to FIGS. Note that FIG.
2 is an exploded perspective view of this battery unit, FIG. 2 is a cross-sectional view of a main part of this battery unit, and FIG. 4 is a schematic perspective view of a battery element. In this battery unit, the battery element 1 is provided with the recess 2a of the exterior material 2.
Then, the outer packaging material 3 is covered with the outer packaging material 2, and the peripheral portions 2a and 3a of the outer packaging materials 2 and 3 are joined by vacuum sealing.

In the present invention, the material of the exterior material having resin layers on both sides of the gas barrier layer is plastic,
Examples thereof include a polymer film, a metal film, rubber, a thin metal plate, and a laminate film having a gas barrier layer and a resin layer. As the material of the exterior material, particularly preferable is
It is a laminated film in which a resin layer is provided on both sides of a gas barrier layer made of metal or metal oxide. If the laminate film is used as the exterior material of the battery element, the weight and size of the electric device can be reduced. The metal layer can be formed using a metal foil, a metal vapor deposition film, a metal sputter, or the like.

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

As the resin layer, thermoplastic resin,
Thermoplastic elastomers, thermosetting resins and plastic alloys are used. These resins include those in which a filler such as a filler is mixed. In addition, the exterior material is provided with a synthetic resin layer on the outer side of the gas barrier layer to function as an outer protective layer, and on the inner side, prevents corrosion by the electrolyte and contact between the metal layer and the battery element, and protects the metal layer. It is possible to form a three-layer structure in which synthetic resin layers functioning as inner protective layers are laminated. The exterior material of the present invention preferably has an inner protective layer made of synthetic resin.

The resin used for the outer protective layer is preferably a resin having excellent chemical resistance and mechanical strength, such as polyethylene, polypropylene, modified polyolefin, ionomer, amorphous polyolefin, polyethylene terephthalate, and polyamide. As the inner protective layer, a chemically resistant synthetic resin is used, and from the viewpoint of ease of heat sealing, polyethylene, polypropylene, modified polyolefin, ionomer, ethylene-vinyl acetate copolymer is preferable, and most preferably polyolefin-based. It is a resin.

A case is formed by 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. It can also be molded by injection molding a synthetic resin. In the case of injection molding, the metal layer is usually formed by sputtering or the like.

Providing the accommodating portion formed of the concave portion in the exterior material can be performed by drawing. As shown in FIG. 3, the exterior material 2 has a flat plate shape. The exterior material 3 is a shallow lidless box shape having a housing portion 3b formed of a rectangular box-shaped recess and a peripheral edge portion 3a protruding outward in a flange shape from four peripheral edges of the housing portion 3b.

As shown in FIGS. 2 and 4, the battery element 1 is formed by stacking a plurality of unit battery elements. The tab 4a or 4b is pulled out from this unit battery element. The tabs 4a from the positive electrode are bundled (that is, superposed on each other), and the positive electrode lead 21 is joined. The tabs 4b from the negative electrode are also bundled, and the negative electrode lead 21 is joined.

As shown in FIG. 2, in the present invention, the sealing material 106 made of synthetic resin is used for the sealing portion of the exterior material through which the leads penetrate, and the sealing material is preliminarily bonded to both surfaces of the lead 21. ing. In addition, from the viewpoint of providing an insulating effect between the lead and the exterior material, the encapsulation material has a portion of the exterior material of 0.1 to 2.0 mm, preferably 0.5 to the outside of the exterior material.
It is preferable to arrange so as to project 1.5 mm (see FIGS. 1 and 2).

In the battery of the present invention, the battery element 1 is accommodated in the accommodating portion 3b of the exterior material 3, and the exterior material 2 is covered. The pair of leads 21 extending from the battery element 1 are drawn out to the outside through the mating surfaces of the peripheral portions 2a, 3a on one side of the exterior materials 2, 3, respectively. After that, under the reduced pressure (preferably vacuum) atmosphere, the peripheral portion 2 of the four peripheral edges of the exterior materials 2 and 3
a and 3a are airtightly joined to each other by a method such as thermocompression bonding or ultrasonic welding, and the battery element 1 is enclosed in the exterior materials 2 and 3.

By joining the peripheral edge portions 2a, 3a to each other, joining piece portions (flaps) 4A, 4F are formed.
The flaps 4A and 4F project outward from the encapsulation portion 4B encapsulating the battery element 1. Therefore, the joining piece portion 4A is bent along the covered portion 4B, and is fastened to the side surface of the covered portion 4B with an adhesive or an adhesive tape (not shown).

In FIG. 3, the exterior materials 2 and 3 are separate bodies, but in the present invention, the exterior materials 2 and 3 may be integrally formed as shown in FIG. In FIG. 6, one side of the exterior material 3 and one side of the exterior material 2 are connected to each other, and the exterior material 2 has a lid shape that is connected to the exterior material 3 in a bendable manner. The concave portion of the housing portion 3b is formed from one side where the exterior materials 2 and 3 are continuous,
This side has the same configuration as that of FIG. 3 except that a flap (joint piece portion) is not formed.

3 and 5, the exterior material 3 having the accommodation portion 3b and the flat exterior material 2 are shown, but in the present invention, as shown in FIG. 6, each of the shallow box-shaped accommodation portions 6b is shown. , 7b,
A peripheral edge portion 6a protruding from the four peripheral edges of the accommodating portions 6b and 7b,
The battery element 1 may be encapsulated by the exterior materials 6 and 7 having 7a. In FIG. 6, the exterior materials 6 and 7 are integrally formed, but they may be separate bodies as in the case of FIG.

In the present invention, as shown in FIG. 7, one flat sheet-like exterior material 8 is folded back along the central piece 8a into two folds, and the first piece 8A and the second side 8B are separated into two pieces. The battery element 1 is formed between the first piece 8A and the second piece 8B, and the peripheral portion 8 of the first piece 8A and the second piece 8B is formed as shown in FIG.
The battery element 1 may be enclosed by joining b. In addition,
In this embodiment, since the bent flap (joint piece portion 4A) is arranged along the envelope portion 4B and fixed with an adhesive or an adhesive tape, the side surface of the battery has high strength and rigidity. .

However, in the present invention, the flap 4A may be left laterally protruding from the envelope 4B. The battery element 1 is a flat plate type battery element formed by stacking a plurality of flat plate-shaped unit battery elements having a positive electrode and a negative electrode in the thickness direction. Since the present invention is particularly suitable for application to a lithium secondary battery, a suitable configuration when the above battery element is a lithium secondary battery element will be described below.

FIG. 9 shows a preferred example of the unit battery element of this lithium secondary battery element. This unit cell element is formed by stacking a positive electrode current collector 22, a positive electrode active material 23, a spacer (electrolyte layer) 24, a negative electrode active material 25, and a negative electrode current collector 26. Usually, the positive electrode active material 23 is bound on one surface of the positive electrode current collector 22, and the negative electrode active material 25 is bound on one surface of the negative electrode current collector 26.

A plurality of the unit battery elements are laminated to form a battery element. At the time of this lamination, the unit battery element in the normal posture (FIG. 9) with the positive electrode on the upper side and the negative electrode on the lower side, and On the contrary, the unit cell elements of the reverse orientation (not shown) with the positive electrode on the lower side and the negative electrode on the upper side are alternately laminated. That is, the unit battery elements adjacent in the stacking direction are stacked so that the same poles (that is, positive electrodes and negative electrodes) face each other.

A positive electrode tab 4a extends from the positive electrode collector 22 of the unit battery element, and a negative electrode tab 4b extends from the negative electrode collector 26. Instead of the unit battery element in which the positive electrode active material, the spacer and the negative electrode active material are laminated between the positive electrode current collector and the negative electrode current collector as shown in FIG. 9, as shown in FIG. 10, the positive electrode current collector 15a or A negative electrode current collector 15b is used as a core material, and a positive electrode 11 and a negative electrode 12 each having a positive electrode active material 11a or a negative electrode active material 12a laminated on both surfaces thereof are prepared.
1 and the negative electrode 12 with a spacer (electrolyte layer) 1 as shown in FIG.
3 may be alternately laminated to form a unit battery element.
In this case, the combination of the pair of the positive electrode 11 and the negative electrode 12 (strictly speaking, from the center in the thickness direction of the current collector 15a of the positive electrode 11 to the center of the current collector 15b in the negative electrode 12 in the thickness direction) is a unit cell element. Equivalent to.

As the positive electrode current collectors 15a and 22, a metal foil of aluminum, stainless steel, nickel or the like can be used, and aluminum is particularly preferable, and the negative electrode current collectors 15b and 26 are preferable.
For this, a metal foil of copper, stainless steel, nickel or the like can be used, and copper is particularly preferable. The thickness of the current collector is 1 to 30
About μm is preferable. As the positive electrode active material, an inorganic compound or an organic compound can be used as long as it can store and release lithium ions. As the inorganic compound, a transition metal oxide, a composite oxide of lithium and a transition metal, a transition metal sulfide, specifically, a transition metal oxide such as MnO, V ₂ O ₅ , V ₆ O ₁₃ or TiO ₂ , Examples thereof include composite oxides of lithium and a transition metal such as lithium nickel oxide, lithium cobalt oxide and lithium manganate, and transition metal sulfides such as TiS ₂ , FeS and MoS ₂ . These compounds may be partially element-substituted to improve their properties. Examples of organic compounds include polyaniline, polypyrrole, polyacene, disulfide compounds, and polysulfide compounds. The positive electrode active material may be a mixture of these inorganic compounds and organic compounds.
Particularly preferred is a composite oxide of at least one transition metal selected from the group consisting of cobalt, nickel and manganese and lithium.

The particle size of the positive electrode active material may be appropriately selected in consideration of the other constituent elements of the battery, but is usually 1 to 3.
0 μm, particularly 1 to 10 μm is preferable because the battery characteristics such as initial efficiency and cycle characteristics are improved. Examples of the negative electrode active material generally include carbon-based materials such as graphite and coke. This carbon-based substance is a metal, a metal salt,
It may be used in the form of a mixture with an oxide or the like, or a coating. As the negative electrode active material, oxides or sulfates of silicon, tin, zinc, manganese, iron, nickel and the like, metallic lithium,
Li-Al, Li-Bi-Cd, Li-Sn-Cd, and other lithium alloys, lithium transition metal nitrides, silicon, and the like can also be used. From the viewpoint of capacity, graphite or coke is preferable. 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, rate characteristics, and cycle characteristics. If this particle size is too large, the electron conductivity deteriorates. Further, it is usually 0.5 μm or more, preferably 7 μm or more.

A binder is preferably used to bind these positive electrode active material and negative electrode active material onto 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 polyethylene,
Alkane-based polymers such as polypropylene and poly-1,1-dimethylethylene; unsaturated polymers such as polybutadiene and polyisoprene; polymers having rings such as polystyrene, polymethylstyrene, polyvinylpyridine and poly-N-vinylpyrrolidone; poly Acrylic polymers such as methyl methacrylate, polyethyl methacrylate, polybutyl methacrylate, polymethyl acrylate, ethyl polyacrylate, polyacrylic acid, polymethacrylic acid, polyacrylamide; polyvinyl fluoride, polyvinylidene fluoride, polytetra Fluorine-based resins such as fluoroethylene; CN group-containing polymers such as polyacrylonitrile and polyvinylidene cyanide; polyvinyl alcohol-based polymers such as polyvinyl acetate and polyvinyl alcohol; polyvinyl chloride Halogen-containing polymers such as polyvinylidene chloride; and conductive polymers such as polyaniline can be used. Also, a mixture of the above polymers,
Even modified products, derivatives, random copolymers, alternating copolymers, graft copolymers, block copolymers and the like can be used.

The blending amount of the binder with respect to 100 parts by weight of the active material is preferably 0.1 to 30 parts by weight, more preferably 1 to 15 parts by weight. If the amount of resin is too small, the strength of the electrode may decrease. If the amount of the resin is too small, the capacity may be lowered or the rate characteristics may be lowered. If necessary, the positive electrode active material and the negative electrode active material may contain additives such as a conductive material and a reinforcing material that exhibit various functions, powders, fillers, and the like.

The conductive material is not particularly limited as long as it can be mixed with the above active material in an appropriate amount to impart conductivity, but usually, carbon powder such as acetylene black, carbon black and graphite, and various metals. Fiber, foil, etc. may be mentioned. As additives, trifluoropropylene carbonate, vinylene carbonate, 1,6-Di
oxaspiro [4,4] nonane-2,7-d
Ione, 12-crown-4-ether and the like can be used to improve the stability and life of the battery. As the reinforcing material, various inorganic or organic spherical or fibrous fillers can be used.

As a method for forming the electrodes on the current collector,
For example, a method in which a powdery active material is mixed with a binder together with a solvent, and dispersed into a coating material by a ball mill, a sand mill, a twin-screw kneader, or the like, which is applied onto a current collector and dried, is preferably performed. In this case, the type of solvent used is not particularly limited as long as it is inert to the electrode material and can dissolve the binder, and for example, commonly used inorganic or organic solvents such as N-methylpyrrolidone. Can also be used.

Further, the electrode material layer can be formed by a method in which the active material is mixed with a binder and heated to be softened and then pressure-bonded or sprayed on the current collector. Further, it may 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 higher the ratio of the ion mobile phase in the electrode, the easier the ion transfer, and the more preferable the ratio is, while the lower the ratio, the higher the capacity. It is preferably 10 to 50% by volume. As the material of the ion mobile phase, the same material as the material of the electrolyte phase described later can be used.

It is preferable that the positive electrode active material and the negative electrode active material have a large film thickness in terms of capacitance and a thin film in terms of rate. The film thickness is usually 20 μm or more, preferably 30 μm or more, more preferably 50 μm or more, and most preferably 80 μm or more. The thickness of the positive electrode and the negative electrode is usually 200 μm or less, preferably 150 μm or less. Spacer (electrolyte layer) 1
3 and 24 usually include various electrolytes such as an electrolyte solution having fluidity and a non-fluidic electrolyte such as a gel electrolyte or a completely solid electrolyte. From the viewpoint of battery characteristics, an electrolytic solution or gel electrolyte is preferable, and from the viewpoint of safety, a non-fluidic electrolyte is preferable. In particular, when a non-fluidic electrolyte is used, liquid leakage can be more effectively prevented for a battery using a conventional electrolytic solution, so the advantage of using a case having shape variability such as a laminate film described below is advantageous. You can make the most of it.

The electrolytic solution used for the electrolyte layer is usually a supporting electrolyte dissolved in a non-aqueous solvent. The supporting electrolyte is a non-aqueous substance that is stable to the positive electrode active material and the negative electrode active material as an electrolyte, and that lithium ions can move to cause an electrochemical reaction with the positive electrode active material or the negative electrode active material. Any one can be used. Specifically, LiPF ₆ , LiAsF ₆ , LiS
bF ₆ , LiBF ₄ , LiClO ₄ , LiI, LiBr,
LiCl, LiAlCl, LiHF ₂ , LiSCN, L
Examples thereof include lithium salts such as iSO ₃ CF ₂ . Of these, LiPF ₆ and LiClO ₄ are particularly preferable.

When these supporting electrolytes are used in a state of being dissolved in a non-aqueous solvent, the concentration is 0.5 to 2.5 mol / L.
Is preferred. The non-aqueous solvent that dissolves these supporting electrolytes 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 ethylmethyl carbonate, glymes such as tetrahydrofuran, 2-methyltetrahydrofuran and dimethoxyethane, γ
One or more of lactones such as -butyl lactone, sulfur compounds such as sulfolane, and nitriles such as acetonitrile are exemplified.

Of 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 ethylmethyl carbonate are particularly preferable. is there. Moreover, you may add additives etc. to these solvents. Examples of the additive include trifluoropropylene carbonate, vinylene carbonate, and 1,6-dioxaspi.
ro [4,4] nonane-2,7-dione, 1
2-crown-4-ether or the like can be used for the purpose of improving the stability and life of the battery.

The gel electrolyte that can be used in the electrolyte layer is usually prepared by holding the above electrolytic solution with a polymer. That is,
The gel electrolyte is one in which the electrolytic solution is usually retained in the polymer network and the fluidity as a whole is significantly reduced. Such a gel electrolyte has properties such as ionic conductivity similar to those of a normal electrolytic solution, but its fluidity and volatility are remarkably suppressed, and its safety is enhanced. The ratio of the polymer in the gel electrolyte is preferably 1 to 50% by weight. If it is too low, the electrolyte cannot be retained, and liquid leakage may occur. If it is too high, the ionic conductivity tends to decrease and the battery characteristics tend to deteriorate.

The polymer used for the gel electrolyte is
There is no particular limitation as long as it is a polymer that can form a gel together with an electrolytic solution, polyester, polyamide, polycarbonate, those produced by polycondensation of polyimide,
Polyurethanes, polyureas, etc. that are produced by polyaddition, polymethylmethacrylate, etc., acrylic derivative polymers, 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 vinylidene fluoride homopolymer but also a copolymer with another monomer component such as hexafluoropropylene. In addition, 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, polyethylene glycol dimethacrylate Can be used polymers are also preferred.

The weight average molecular weight of the above polymer is usually 10
It is in the range of 000 to 5,000,000. When the molecular weight is low, it becomes difficult to form a gel. If the molecular weight is high, the viscosity becomes too high, which makes the handling difficult. The concentration of the polymer in the electrolytic solution may be appropriately selected depending on the molecular weight, but is preferably 0.1 to 30% by weight. If the concentration is too low, it becomes difficult to form a gel, and the retention of the electrolytic solution decreases, which may cause problems of fluidity and liquid leakage. If the concentration is too high, the viscosity becomes too high, which causes difficulty in the process, and the ratio of the electrolytic solution may decrease to decrease the ionic conductivity and deteriorate the battery characteristics such as the rate characteristics.

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

As the electrolyte layer, a porous sheet such as a porous membrane impregnated with the above electrolyte may be used. The thickness of the electrolyte layer is usually 1 to 200 μm, preferably 5 to 10 μm.
It is 0 μm. The thickness of the porous sheet is usually 1 μm or more, preferably 5 μm or more, and usually 20 μm or more.
Those having a thickness of 0 μm or less, preferably 100 μm or less are used. The porosity is usually 10 to 95%, preferably 30 to
It is about 85%. As a material for the porous sheet, a polyolefin or a polyolefin in which some or all of hydrogen atoms are fluorine-substituted 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.

The planar shape of the electrode is arbitrary and can be a quadrangle, a circle, a polygon, or the like. As shown in FIGS. 12 to 14, the current collectors 22, 26 or 15a, 15b are usually
Tabs 4a and 4b for lead coupling are arranged in series. When the electrode has a rectangular shape, a tab 4a protruding from the positive electrode current collector is usually formed near one side of one side of the electrode as shown in FIG. 12, and the tab 4b of the negative electrode current collector is near the other side. Form.

The stacking of a plurality of battery elements is effective in increasing the capacity of the battery, but at this time, the tabs 4a and 4b from each battery element are usually arranged in the thickness direction. The positive and negative lead connection terminals are formed by being combined. As a result, a large capacity battery element 1 can be obtained. As shown in FIG. 6, the tabs 4a and 4b are joined with leads 21 made of flaky metal. As a result, the lead 21 and the positive and negative electrodes of the battery element are electrically coupled. Connection between tabs 4a and 4b and tab 4
The a and 4b can be connected to the lead 21 by resistance welding such as spot welding, ultrasonic welding or laser welding.

It is preferable that the above-mentioned exterior materials 2, 3, 6, 7, and 8 have shape variability. As a result, it is possible to easily change the shape of the battery in various ways. Also, 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.

[0064]

EXAMPLES The present invention will now be described in more detail with reference to examples. [Sealing Material] A film (100 μm thick) obtained by molding polypropylene modified with maleic anhydride (trade name “MODIC AP-P513V” manufactured by Mitsubishi Chemical) was used.

[Lead Primer Material] A mixture obtained by suspending a modified polyolefin resin acid in an organic solvent (manufactured by Mitsubishi Kagaku Co., Ltd., trade name “Surflen AP-343”) was used. After coating, the dried coating thickness was 20 μm. [Vacuum heat sealing conditions] The mating surface of the exterior material including the lead penetrating portion was pressed at 195 ° C. for 5 seconds at 0.5 MPa,
Heat fused.

Example 1 The material of the lead was aluminum foil (A1N30-
O), and copper foil (C1100-O) was used for the negative electrode. The thickness is 80 μm, the width is 3 mm, and the edges are deburred. The encapsulant is polypropylene modified with maleic anhydride (trade name "MODIC AP-"
P513V ") to obtain a film (100μ
m thickness) was used. The center line distance of each lead of the positive electrode and the negative electrode was 5 mm, and the encapsulant was placed on the upper and lower sides of the lead so as to straddle the positive and negative leads.
Pressure was applied at MPa to cause fusion. After fusion, pitch 35mm
Then, the lead parts were manufactured by cutting.

Example 2 A mixture (Mitsubishi Chemical, trade name "Surflen AP-343") obtained by suspending a polyolefin resin acid modified product in an organic solvent was sealed in advance (before assembling with a sealing material). A lead component was manufactured in the same manner as in Example 1 except that the coating was applied to the fixing material attaching portion and then dried. The coating thickness of the mixture was 20 μm.

Example 3 A lead component was prepared in the same manner as in Example 1 except that the end portions of the sides of the positive electrode lead and the negative electrode lead in the longitudinal direction were sanded to form curved surfaces in advance (before being assembled with the encapsulating material). Manufactured. Example 4 A positive electrode formed by forming a 60 μm-thick active material layer made of lithium cobalt oxide as an active material, polyvinylidene fluoride and acetylene black on an aluminum current collector having a thickness of 20 μm, and graphite as an active material. A 40 μm-thick active material layer made of polyvinylidene fluoride with a thickness of 1
A negative electrode formed on a 0 μm copper current collector and having a thickness of about 2
Laminated 0 μm microporous polyethylene stretched films were laminated to form a flat unit battery element composed of a lithium secondary battery. As the electrolyte, a gel electrolyte in which an electrolytic solution prepared by dissolving LiPF ₆ in a carbonate solvent was held by an acrylic polymer was used. This gel electrolyte was made to exist in the voids of the stretched film and in the positive electrode and the negative electrode. Further, the peripheral portion of the stretched film constituting the spacer was made larger than the peripheral portions of the positive electrode and the negative electrode.

20 unit battery elements thus obtained were laminated in the thickness direction, positive and negative electrode tabs were assembled, and the leads of each aluminum foil and copper foil were ultrasonically welded. This was housed in an exterior material made of a laminated composite material and vacuum-sealed to obtain a flat plate type battery as shown in FIGS. At this time, the lead used was the lead component manufactured in Example 1.
The vacuum heat sealing conditions are as described above.

Example 5 A battery was manufactured in the same manner as in Example 4 except that the lead component manufactured in Example 2 was used instead of the lead component manufactured in Example 1. Example 6 A battery was manufactured in the same manner as in Example 4 except that the lead component manufactured in Example 3 was used instead of the lead component manufactured in Example 1.

[0071]

According to the present invention, the sealing material can be used without increasing the number of steps for assembling the battery, and the displacement of the sealing material during the battery assembly can be prevented.

[Brief description of drawings]

FIG. 1 is a perspective view of a flat plate type secondary battery.

FIG. 2 is a sectional view of a main part of a flat plate type secondary battery.

FIG. 3 is an exploded perspective view of a flat plate type secondary battery.

FIG. 4 is a perspective view showing a battery element of a flat plate type secondary battery.

FIG. 5 is a perspective view of a flat plate type secondary battery in the process of being manufactured.

FIG. 6 is a perspective view in the process of manufacturing a flat plate type secondary battery.

FIG. 7 is a perspective view of the flat plate secondary battery in the process of being manufactured.

8 is a plan view of the flat plate secondary battery of FIG. 10 in the process of being manufactured.

FIG. 9 is a perspective view of a unit battery element.

FIG. 10 is a schematic cross-sectional view of a positive electrode or a negative electrode.

FIG. 11 is a schematic cross-sectional view of a battery element.

FIG. 12 is a diagram of a lead component of the present invention.

FIG. 13 is a cross-sectional view of the lead component of the present invention.

FIG. 14 is a diagram at the time of manufacturing the lead component of the present invention.

[Explanation of symbols]

101 Coating of Lead with Synthetic Resin Having Polar Group 106 Encapsulating Material 1 Battery Elements 2, 3, 6, 7, 8 Exterior Materials 4a, 4b Tabs 4A, 4F Joining Pieces (Flaps) 4B Encapsulation Section 11 Positive Electrode 11a Positive Electrode Active material 12 Negative electrode 12b Negative electrode active material 13 Non-fluidic electrolyte layer 15a Positive electrode current collector 15b Negative electrode current collector 21 Lead 22 Positive electrode current collector 23 Positive electrode active material 24 Spacer (electrolyte layer) 25 Negative electrode active material 26 Negative electrode current collector 50 Battery unit C Lead longitudinal side

Continued front page    (72) Inventor Noritaka Ibuki             10-10 Shiodotsu, Kurashiki City, Okayama Prefecture Mitsubishi Chemical             Within the corporation F-term (reference) 5H011 AA09 AA10 GG09 HH02 JJ07                       JJ25 KK01                 5H022 AA00 AA09 BB12 BB17 BB21                       CC02 EE01 EE04 EE06 EE08                       EE10 KK08                 5H029 AJ14 AJ15 AK02 AK03 AK05                       AK15 AK16 AK18 AL01 AL02                       AL06 AL07 AL12 AL18 AM02                       AM03 AM04 AM05 AM07 AM16                       BJ04 CJ05 CJ06 CJ22 DJ05                       EJ01 EJ11 HJ04

Claims (9)

[Claims] 1. A positive electrode lead, a negative electrode lead, and a sealing material, wherein a sealing material is provided on both surfaces of the positive electrode lead and the negative electrode lead so as to straddle the positive electrode lead and the negative electrode lead. A lead component in which a lead, a negative electrode lead, and a sealing material are integrated. 2. The lead component according to claim 1, wherein a sealing material is bonded to the positive electrode lead and the negative electrode lead by heat fusion or ultrasonic fusion. 3. The lead component according to claim 1, wherein a primer is applied to a sealing material joint portion of the positive electrode lead and the negative electrode lead. 4. The positive electrode lead is made of aluminum,
The lead component according to claim 1, wherein the negative electrode lead is made of copper. 5. The lead component according to claim 1, wherein the ends of the sides of the lead in the longitudinal direction are curved surfaces. 6. The lead component according to claim 1, wherein the sealing material is made of a polyolefin resin having a polar group. 7. The lead thickness a and the sealing material thickness b are: [Formula 1] b> a / 2 The lead component according to any one of claims 1 to 6, which satisfies the above condition. 8. A battery in which a battery element is interposed between packaging materials, and the battery elements are hermetically sealed by sealing the peripheral portions of the packaging material, the packaging material having resin layers on both sides of a gas barrier layer. The exterior material is provided, and has metal leads that are electrically coupled to the positive electrode and the negative electrode independently of each other, and the leads penetrate the sealing portion of the exterior material and are exposed to the outside of the exterior material. A battery, wherein the lead component according to any one of claims 1 to 7 is used. 9. A band-shaped positive electrode lead and a band-shaped negative electrode lead are arranged in parallel, and a sealing material is provided on both sides of the positive electrode lead and the negative electrode lead so as to straddle the polar lead and the negative electrode lead at regular intervals. Is arranged, and then heat fusion or ultrasonic fusion is performed, and the leads are cut at regular intervals.