JP2001057182A - Electrochemical device and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve cycle life and storage stability at high temperatures, by interposing an adhesive layer between a metal and a resin, which is sealed to the jacket bag of a laminated film having a metal layer and a resin layer and is laminated directly by a lead-through terminal for the outside, and a polyolefin resin layer to coat the layer between the lead-through terminal of a sealing part and the jacket bag. SOLUTION: In this electrochemical device 1, an electrochemical element is sealed by first and second sealing parts which are thermally bonded to the jacket bag of a laminated film 30, having a metal layer and a thermally adhesive resin layer. Lead-through terminals 13, 14, running outside through the second sealing part of the electrochemical element, directly laminate an adhesive layer 41 between the metal and the resin. The read-through terminals 13, 14 causes interpose an intermediate layer 40 comprising a polyolefin resin layer 42 for coating the adhesive layer 41 to interpose between the metal and the resin between the lead-through terminal and the jacket bags. Thereby, the electrochemical device sealed is given sufficient adherence between the jacket bag and the lead-through terminal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrochemical device such as a polymer lithium secondary battery and an electric double layer capacitor, and a method of manufacturing the same. It relates to a manufacturing method.

[0002]

2. Description of the Related Art In recent years, carbon materials, tin oxide, silicon oxide and the like have been used as negative electrode active materials called lithium secondary batteries.
Secondary batteries are used or considered for various electronic products and electric vehicles. These lithium secondary batteries are
A so-called electrolyte solution in which an electrolyte salt is dissolved in a liquid solvent is used. Batteries using an electrolytic solution have the advantage of low internal resistance, but, on the other hand, have the problem of liability to leak and ignition. To solve such problems, studies on electrolytes containing no solvent, that is, solid electrolytes, have been made for many years. For example, a gel polymer solid electrolyte composed of a polymer, an electrolyte salt, and a solvent has recently been spotlighted.

[0003] Such a gel-like polymer solid electrolyte is
In some cases, the conductivity is close to that of a liquid and shows a value on the order of 10 ⁻³ S · cm ⁻¹ .

A battery using a solid polymer electrolyte does not leak easily because it does not use a liquid electrolyte. Therefore,
Unlike a conventional battery using a liquid electrolyte, it is not necessary to mechanically caulk with a metal container and a polymer packing in question. In a battery using a polymer solid electrolyte, liquid leakage can be prevented only by using a laminated film composed of a polymer film and a metal foil as an outer bag (container).

However, the adhesion between the lead terminal (metal foil) extending from the inside of the battery to the outside and the polymer film (thermally adhesive resin layer) on the innermost surface of the laminate film is insufficient, and the sealing property of the battery is poor. However, this is not sufficient, and this has been a problem in terms of the cycle life of the battery.

In order to improve the above-mentioned drawbacks, Japanese Patent Application Laid-Open
Japanese Patent No. 289698 discloses a thin sealed battery in which a power generation element containing both positive and negative electrodes and an electrolyte is housed in an outer bag made of a laminate sheet in which a heat-fusible resin layer is fixed to both surfaces of a metal layer. A current collecting tab made of metal is provided on each of the positive and negative electrodes, and each of the current collecting tabs is led out of the battery from a current collecting tab lead-out portion of the outer bag,
And the current collection tab lead-out portion is sealed by heat sealing with a heat-fusible modified resin layer interposed between the current collection tab and the inner surface of the outer package. Is disclosed.

[0007]

However, the above-mentioned modified resin layer having a heat-sealing property has a disadvantage that the sealing property is still insufficient. Analysis of the cause revealed that the denatured resin layer was very weak to the lithium salt-containing organic electrolyte.However, it was very difficult to make a battery so that the electrolyte did not touch the terminal seal during injection. Was difficult.

An object of the present invention is to provide an electrochemical device using a polymer solid electrolyte impregnated with an organic electrolytic solution containing a lithium salt, and to derive a heat-adhesive resin layer of an outer bag into an outer bag (container). An electrochemical device that is thermally bonded with terminals in between and encapsulates the battery can solve the problem that the adhesion between the outer bag and the lead-out terminal is insufficient, and the cycle life and high-temperature storage characteristics of the battery are not good. It is to provide a manufacturing method.

[0009]

This and other objects are attained by the present invention described below. (1) An electrochemical device having an outer bag and an electrochemical element sealed in the outer bag, wherein the outer bag is a laminate film having a metal layer and a heat-adhesive resin layer. The chemical device has a lead-out terminal that is sealed and sealed by a heat-sealed seal portion between the heat-adhesive resin layers of the outer package, and leads to the outside through the seal portion, and the lead-out of the seal portion. An electrochemical device having a metal-resin adhesive layer directly laminated on the lead-out terminal and an olefin resin layer covering the metal-resin adhesive layer between the terminal and the outer bag. . (2) The electrochemical device according to (1), wherein the electrochemical device has both positive and negative electrodes and a solid polymer electrolyte. (3) The electrochemical device according to the above (1) or (2), which is a lithium secondary battery. (4) The electrochemical device according to the above (1) or (2), which is an electric double layer capacitor. (5) The electrochemical element is housed in an outer bag that is a laminate film having a metal layer and a thermoadhesive resin layer, and the lead terminals connected to the positive and negative electrodes of the electrochemical element are connected to the thermoadhesive resin of the outer bag. A method for manufacturing an electrochemical device in which a seal portion is formed by thermal bonding sandwiching between layers and sealing is performed, wherein a metal-resin adhesive layer from the lead terminal side to a portion corresponding to the seal portion of the lead terminal, A lead terminal coating step of thermally bonding with an intermediate layer laminated in the order of the polyolefin resin layer, and a polymer film between the positive and negative electrodes of the electrochemical device after the lead terminal coating step is impregnated with an electrolytic solution to form a polymer. A method for manufacturing an electrochemical device, comprising: a pouring step of obtaining a solid electrolyte; and a sealing step of sealing the electrochemical element after the pouring step into the outer bag with the seal portion. (6) The lead-out terminal covering step includes applying a metal-resin adhesive to a portion corresponding to the seal portion of the lead-out terminal to form the metal-resin adhesive layer. The method for producing an electrochemical device according to the above (5), wherein the polyolefin resin film is thermally bonded on the agent layer. (7) The lead-out terminal covering step includes: attaching a fusion-bonded sheet having a metal-resin adhesive layer and a polyolefin resin layer to a portion corresponding to the seal portion of the lead-out terminal;
The method for producing an electrochemical device according to the above (5), wherein the inter-resin adhesive layer is disposed on the lead terminal side and thermally bonded.

[0010]

As a result of repeated studies, the present inventor has found that the modified resin layer applied on the lead-out terminal made of metal is covered with a polypropylene (PP) layer, and then laminated with an outer bag to form a seal. It was found that the resistance of the part to the electrolytic solution was dramatically improved.

That is, when the inner surface of the outer bag is a heat-adhesive resin layer and a metal-resin adhesive layer is arranged between the heat-adhesive resin layer and the lead-out terminal, the inner surface of the outer bag has a thermal adhesive property. The adhesion between the resin layer and the lead terminals (metals such as aluminum and nickel) is improved. However, since the metal-resin adhesive comes into contact with the electrolyte during the electrolyte injection and the adhesive strength is deteriorated as it is, by providing the polyolefin resin layer on the metal-resin adhesive in advance, Metal
The contact of the electrolyte with the resin-to-resin adhesive can be avoided. Since the strength at the time of fusion does not decrease between the polyolefin resin layer and the heat-adhesive resin of the outer package even if the electrolytic solution is present, the sealing property can be maintained. Further, if the sealing property is good, it is possible to prevent the moisture in the atmosphere from entering the inside, so that an electrochemical device having good cycle life and high-temperature storage characteristics can be obtained. Further, since the metal-resin adhesive can be protected, there is an advantage that the kind of the adhesive is not so limited.

[0012]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic structure of the electrochemical device of the present invention. FIG. 2 shows FIG.
FIG. 3C is a cross-sectional view taken along the line AA in FIG. 3C, showing a cross-sectional structure of a seal portion including a lead terminal.

The electrochemical device 1 shown in FIG.
The lead-out terminals 13 and 14 of the electrochemical element 10 shown in FIG. 1A are placed in an outer bag 20 formed in a bag shape by the first seal portion 21 shown in FIG. It is stored in a state of protruding to the outside, and the open end surface of the outer bag 20 is sealed by heat fusion with the lead-out terminals 13 and 14 interposed therebetween to form a second seal portion 22. Electrochemical device 1
Has a structure in which the electrochemical element 10 is sealed in the outer bag 20 and the lead-out terminals 13 and 14 project from the second seal portion 22 to the outside.

The electrochemical element 10 has positive and negative electrodes 11, 12 made of metal foil such as aluminum foil or copper foil.
And a solid polymer electrolyte (not shown). As shown in FIG. 1A, lead terminals 13 and 14 are connected to the positive and negative electrodes 11 and 12, respectively. Outgoing terminal 13, 1
Reference numeral 4 is made of metal foil such as aluminum, copper, nickel, and stainless steel. The lead terminals 13 and 14 are conceptually provided with the seal portions 13 in the regions covered by the second seal portions 22, respectively.
a and 14a.

The outer bag 20 has a laminated film 3 in which a polyolefin resin layer such as polypropylene or polyethylene or a heat-resistant polyester resin layer as a heat-adhesive resin layer is laminated on both sides of a metal layer such as aluminum.
0. As shown in FIG. 1 (b), the outer bag 20 heat-bonds the two laminated films 30 to each other at the heat-adhesive resin layers on the three end surfaces thereof to form a first seal portion 21. It is formed in a bag shape with one side opened. Alternatively, a single laminated film may be folded back and the both end faces may be thermally bonded to form a seal portion to form a bag.

In the second seal portion 22 of the electrochemical device 1 of the present invention, as shown in FIG. 2, the lead-out terminals 13 and 14 are sandwiched between the laminate films 30 constituting the outer bag 20. 14 and laminated film 30
Between the metal-resin adhesive layer 41 and the olefin resin layer 42 covering the metal-resin adhesive layer directly laminated on the lead-out terminal. It has an intermediate layer 40.

Heretofore, the adhesion between the lead terminal formed of such a metal foil and the heat-adhesive resin layer forming the outer package has been insufficient. In the electrochemical device 1 of the present invention, the metal-resin adhesive layer 41 is directly laminated so as to cover the sealing portions 13a and 14a of the lead-out terminals 13 and 14, and is connected to a metal (aluminum, copper, nickel, stainless steel, etc.). It maintains adhesion to polyolefin and the like, and is an essential material for pulling out the lead-out terminal from the laminate bag and maintaining the sealing.

Examples of the metal-resin adhesive layer 41 include acid-modified polyethylene such as carboxylic acid, acid-modified polypropylene, epoxy resin, and modified isocyanate. Since the metal-resin adhesive layer 41 is provided between the metal and the polyolefin resin to improve the adhesion between the metal and the polyolefin resin, the metal-resin adhesive layer 41 covers the sealing portions 13a and 14a of the lead-out terminals 13 and 14. The size of is sufficient. The thickness of the metal-resin adhesive layer 41 is preferably about 1 to 100 μm.

In the present invention, the metal-resin adhesive layer 41 is further covered with an olefin resin layer 42 in order to protect the metal-resin adhesive layer 41 from an electrolytic solution.

The polyolefin resin layer 42 functions as a heat-adhesive resin layer because it has excellent mutual adhesion with the polyolefin resin layer as the heat-adhesive resin layer of the laminate film 30. The thickness of the polyolefin resin layer 42 is 1
It is preferably about 0 to 200 μm. Examples of the polyolefin resin include polyethylene, polypropylene, and acid-modified products thereof. Due to compatibility, when the heat-adhesive resin layer of the laminate film 30 is made of polyethylene, the polyolefin resin layer 42 of the intermediate layer 40 is also made of polyethylene. When the heat-adhesive resin layer of the laminate film 30 is made of polypropylene, the intermediate layer 40 is made of polyethylene. It is preferable that the polyolefin resin layer 42 is also made of polypropylene from the viewpoint of adhesiveness.

The lead terminal covering step of covering the lead terminal seal portions 13a and 14a with the intermediate layer 40 composed of such a metal-resin adhesive layer / polyolefin resin layer is as follows.
For example, a metal-resin adhesive is applied to the terminal seal portion 13.
a, 14a, and then a polyolefin film may be thermally welded onto the metal-resin adhesive layer. Alternatively, a method in which a fusion film composed of a metal-resin adhesive layer / polyolefin resin layer is thermally welded to the sealing portions 13a and 14a of the lead-out terminals can be adopted. During this lead-out terminal coating process,
The lead-out terminal may be welded or bonded to the battery or the electric double layer capacitor before the electrolyte injection, or may be a single terminal. In any case, the intermediate layer 40 of the present invention
Must be attached to the lead-out terminals 13 and 14 before the electrolyte is injected.

The fusion film may be in the form of a tube. In the case of a tubular shape, the tube cut to the length of the seal portions 13a and 14a is inserted into the lead-out terminal, and the seal portion 1
3a and 14a are heat-sealed.

After the lead-out terminal coating step, the battery positive electrode and the battery negative electrode having the above-described treated lead-out terminal and the element having the polymer film are immersed in a lithium salt-containing organic electrolytic solution to be impregnated with the electrolytic solution. A liquid injection step is performed in which the polymer film is converted into a polymer solid electrolyte to produce an electrochemical device.

Thereafter, the electrochemical device is inserted into a laminate bag made of metal and resin, and the opening is heat-sealed.
An electrochemical device is obtained by a sealing process.

In order to ensure insulation between the metal foil forming the laminate film and the lead-out terminal, the laminated film constituting the outer package is formed from the inner layer side with a heat-adhesive resin layer / polyester resin layer / metal foil / polyester. It is preferable to use a laminate film having a laminated structure of resin layers. By using such a laminated film, the high melting point polyester resin layer remains without melting at the time of thermal bonding, so that a separation distance between the lead terminal and the metal foil of the outer package can be ensured, and insulation can be ensured. . Therefore, the thickness of the polyester resin layer of the laminate film is preferably about 5 to 100 μm.

The electrochemical device of the present invention can be used as a lithium secondary battery or an electric double layer capacitor as described below.

<Lithium rechargeable battery> Lithium 2 of the present invention
Although the structure of the secondary battery is not particularly limited, it is generally composed of a positive electrode, a negative electrode, and a solid polymer electrolyte, and is applied to a stacked battery, a cylindrical battery, and the like.

The electrode to be combined with the solid polymer electrolyte may be appropriately selected from those known as electrodes for a lithium secondary battery, and is preferably used as an electrode active material and a gel electrolyte. Is used.

For the negative electrode, a negative electrode active material such as a carbon material, lithium metal, lithium alloy or oxide material is used. For the positive electrode, an oxide or carbon material capable of intercalating / deintercalating lithium ions is used. It is preferable to use such a positive electrode active material as described above. By using such an electrode, a lithium secondary battery having excellent characteristics can be obtained.

The carbon material used as the electrode active material may be appropriately selected from, for example, mesocarbon microbeads (MCMB), natural or artificial graphite, resin fired carbon material, carbon black, carbon fiber and the like. These are used as powders. Above all, graphite is preferred, and its average particle size is preferably 1 to 30 μm, particularly preferably 5 to 25 μm. If the average particle size is too small, the charge / discharge cycle life tends to be short and the variation in capacity (individual difference) tends to be large. If the average particle size is too large, the dispersion of the capacity becomes extremely large, and the average capacity becomes small. It is considered that the capacity variation occurs when the average particle size is large because the contact between the graphite and the current collector and the contact between the graphites vary.

Lithium ion is intercalated day
Intercalatable oxides include lithium
Composite oxides are preferred, for example, LiCoO_Two, LiM
n_TwoO _Four, LiNiO_Two, LiV_TwoO_FourAnd the like.
The average particle size of these oxide powders is about 1 to 40 μm.
It is preferred that

If necessary, a conductive additive is added to the electrode. Preferred examples of the conductive auxiliary agent include metals such as graphite, carbon black, carbon fiber, nickel, aluminum, copper, and silver. Particularly, graphite and carbon black are preferable.

The electrode composition of the positive electrode is as follows: active material: conductive auxiliary agent: gel electrolyte = 30 to 90: 3 to 10: 1 by weight.
The range of 0 to 70 is preferable. In the negative electrode, active material: conductive auxiliary agent: gel electrolyte = 30 to 90: 0 to 10: 1 by weight ratio.
A range from 0 to 70 is preferred. The gel electrolyte is not particularly limited, and a commonly used gel electrolyte may be used. Also,
An electrode containing no gel electrolyte is also preferably used. In this case, a fluorine resin, a fluorine rubber, or the like can be used as the binder, and the amount of the binder is about 3 to 30 wt%.

In the production of the electrode, first, an active material and, if necessary, a conductive auxiliary are dispersed in a gel electrolyte solution or a binder solution to prepare a coating solution.

Then, this electrode coating solution is applied to a current collector. The means for applying is not particularly limited, and may be determined as appropriate according to the material and shape of the current collector. Generally, a metal mask printing method, an electrostatic coating method, a dip coating method, a spray coating method, a roll coating method, a doctor blade method, a gravure coating method, a screen printing method, and the like are used.
Thereafter, if necessary, a rolling treatment is performed by a flat plate press, a calender roll, or the like.

The current collector may be appropriately selected from ordinary current collectors according to the shape of the device used by the battery and the method of arranging the current collector in the case. Generally, aluminum or the like is used for the positive electrode, and copper, nickel, or the like is used for the negative electrode.
Note that a metal foil, a metal mesh, or the like is generally used as the current collector. Although the metal mesh has lower contact resistance with the electrode than the metal foil, a sufficiently low contact resistance can be obtained even with the metal foil.

Then, the solvent is evaporated to produce an electrode. The coating thickness is preferably about 50 to 400 μm.

The polymer film is, for example, PEO (polyethylene oxide), PAN (polyacrylonitrile)
And a polymer microporous membrane such as PVDF (polyvinylidene fluoride).

Such a positive electrode, a polymer film, and a negative electrode are laminated in this order and pressed to form a battery body.

The electrolyte for impregnating the polymer membrane generally comprises an electrolyte salt and a solvent. As the electrolyte salt, for example, Li
BF ₄ , LiPF ₆ , LiAsF ₆ , LiSO ₃ C
Lithium salts such as F ₃ , LiClO ₄ , and LiN (SO ₂ CF ₃ ) ₂ can be used.

The solvent of the electrolytic solution is not particularly limited as long as it has good compatibility with the above-mentioned solid polymer electrolyte and electrolyte salt, but in a lithium battery or the like, a polar organic solvent which does not decompose even at a high operating voltage. Solvents, for example, carbonates such as ethylene carbonate (abbreviation EC), propylene carbonate (abbreviation PC), butylene carbonate, dimethyl carbonate (abbreviation DMC), diethyl carbonate, ethyl methyl carbonate, etc., tetrahydrofuran (THF), 2-methyltetrahydrofuran and the like A cyclic ether, a cyclic ether such as 1,3-dioxolan, 4-methyldioxolan, a lactone such as γ-butyrolactone, a sulfolane, and the like are preferably used. 3-Methylsulfolane, dimethoxyethane, diethoxyethane, ethoxymethoxyethane, ethyldiglyme and the like may be used.

When it is considered that the electrolyte is composed of the solvent and the electrolyte salt, the concentration of the electrolyte salt is preferably 0.3 to 5 mol.
l / l. Usually, it exhibits the highest ionic conductivity at around 1 mol / l.

When a microporous polymer film is immersed in such an electrolytic solution, the polymer film absorbs the electrolytic solution and gels to form a solid polymer electrolyte.

When the composition of the solid polymer electrolyte is represented by a copolymer / electrolyte solution, the ratio of the electrolyte solution is preferably from 40 to 90% by weight in view of the strength of the membrane and the ionic conductivity.

<Electric Double Layer Capacitor> Electric 2 of the present invention
Although the structure of the multilayer capacitor is not particularly limited, usually, a pair of polarizable electrodes are arranged via a polymer solid electrolyte, and an insulating gasket is arranged around the polarizable electrode and the polymer solid electrolyte. I have. Such electricity 2
The multilayer capacitor may be any type called a coin type, a paper type, a laminated type, or the like.

As the polarizable electrode, activated carbon, activated carbon fiber, or the like is used as a conductive active material, and a fluororesin, fluororubber, or the like is added as a binder. Then, it is preferable to use the mixture formed on a sheet-like electrode. The amount of the binder is about 5 to 15 wt%. Further, a gel electrolyte may be used as the binder.

The current collector used for the polarizable electrode is platinum,
It may be a conductive rubber such as a conductive butyl rubber or the like, may be formed by spraying a metal such as aluminum or nickel, or may be provided with a metal mesh on one surface of the electrode layer.

The electric double layer capacitor is formed by combining the above-mentioned polarizable electrode and the solid polymer electrolyte.

The polymer film is made of, for example, PEO (polyethylene oxide), PAN (polyacrylonitrile)
And a polymer microporous membrane such as PVDF (polyvinylidene fluoride).

As the electrolyte salt, (C ₂ H ₅ ) ₄ NB
F ₄ , (C ₂ H ₅ ) ₃ CH ₃ NBF ₄ , (C ₂ H ₅ ) ₄ PB
F _4, and the like.

The non-aqueous solvent used for the electrolytic solution may be various known ones, and propylene carbonate, ethylene carbonate, γ-
Butyrolactone, acetonitrile, dimethylformamide, 1,2-dimethoxyethane, sulfolane alone or a mixed solvent is preferred.

The concentration of the electrolyte in such a non-aqueous solvent-based electrolyte solution may be 0.1 to 3 mol / l.

When a microporous polymer film is immersed in such an electrolytic solution, the polymer film absorbs the electrolytic solution and gels to form a solid polymer electrolyte.

When the composition of the solid polymer electrolyte is represented by a copolymer / electrolyte solution, the ratio of the electrolyte solution is preferably from 40 to 90% by weight in view of the strength of the membrane and the ionic conductivity.

As the insulating gasket, an insulator such as polypropylene or butyl rubber may be used.

[0056]

[Example 1] (Production of battery) Aluminum foil and nickel foil having a width of 4 mm, a length of 50 mm and a thickness of 0.1 mm were prepared as terminal materials. An acid-modified polypropylene (Unistol R-200 of Mitsui Chemicals, Inc.) was sprayed as a metal-resin adhesive onto the sealing portion, and then a 5 mm × 5 mm square 80 mm thick film was formed.
A lead terminal was obtained by placing a μm PP sheet above and below the sealing portion and performing heat pressing.

The electrodes were LiCoO ₂ , carbon black (HS-100, manufactured by Denki Kagaku Kogyo), PVDF
(Polyvinylidene fluoride) was applied to an aluminum foil by a doctor blade method to prepare. The negative electrode is mesocarbon microbeads (MCMB), HS-10
0, made of PVDF was applied to copper foil by a doctor blade method. A microporous PVDF membrane was used as a polymer solid electrolyte. Positive and negative electrodes are 31 mm wide and 41 mm long
Cut into pieces. The separator was cut into a width of 33 mm and a length of 43 mm.

The production of the battery element was performed as follows. First, the positive electrode and the separator were laminated and laminated by hot pressing.
The laminating conditions were 150 ° C. and a pressure of 5 kgcm ⁻² for 2 minutes. A negative electrode was laminated thereon and laminated similarly.

The above aluminum lead terminal of the battery element was resistance welded to the above aluminum lead terminal, and the above copper lead terminal was also resistance welded to the copper current collector. This battery element is EC
(Ethylene carbonate) and DMC (dimethyl carbonate) were immersed for 30 minutes in 330 ml of an electrolyte obtained by dissolving 1 M of LiPF _{6 in} a mixed solvent of 1: 2 by volume. After taking out the battery body from the electrolyte, the electrolyte adhering to the electrode surface was wiped off. This battery element absorbed the electrolytic solution and became a gel state. PET (12 μm) / aluminum (20 μm) / PET (12 μm) / PP (80 μm)
The battery element was inserted into a laminate bag (with the innermost layer being PP) made of, and the opening was heat-sealed to produce a sheet-type polymer lithium secondary battery.

FIG. 3 shows the relationship between the number of cycles and the discharge capacity. Table 1 shows the weight loss ratio when another battery was stored at 110 ° C. Table 1 shows the weight loss rates of the five samples. The weight reduction rate was determined by the following equation.

Weight reduction rate (%) = ((battery weight after storage at 110 ° C.) − (Battery weight before storage)) / (weight of electrolyte contained in battery) × 100 The number of short-circuited products generated when the sample was prepared was shown.

[Example 2] (Preparation of battery) Acid-modified polypropylene was not sprayed on aluminum foil and nickel foil as terminal materials, and acid-modified polypropylene (Enistor R-20 manufactured by Mitsui Chemicals, Inc.) was used.
0) An experiment was performed in the same manner as in Example 1 except that a sheet having a structure of 20 μm / 80 μm PP was prepared, and this was fused to a terminal with the acid-modified polypropylene side down.

Comparative Example 1 (Preparation of Battery) Acid-Modified Polypropylene (Mitsui Chemicals, Inc.)
Ennistor R-200) was sprayed onto the terminals and used, but no propylene sheet was used.
A sheet-type lithium secondary battery was produced in the same manner as in Example 1.

[0064]

[Table 1]

FIG. 3 shows that the present invention improved the hermeticity of the battery and, as a result, improved the charge / discharge cycle life. Further, from the weight reduction rates in Table 1, it can be seen that the electrolyte in the conventional battery was largely evaporated, and the present invention has the effect of preventing the leakage of the internal electrolyte.

Example 3 (Preparation of Capacitor) Active Material: LiCoO ₂ , Conductive Aid: Acetylene Black, Polymer Material: PVDF [KynarFlex 2801 (manufactured by Elf Atochem Co.)], (Polyvinylidene fluoride and 6 F Copolymer with propylene chloride), solvent: acetone by weight ratio, active material: conductive auxiliary agent: polymer substance: solvent =
A polymer solution was prepared by mixing at a ratio of 8: 1: 1: 15 and formed into a film to obtain a molded product. This compact was thermocompression-bonded to a current collector to form a positive electrode.

A negative electrode was fabricated in the same manner as the positive electrode except that the active material was graphite and the active material: conductive auxiliary agent: polymer substance: solvent was 8.5: 0.5: 1: 15. did.

A microporous PVDF membrane was used as a polymer solid electrolyte.

Next, the positive electrode and the negative electrode were laminated with a polymer solid electrolyte interposed therebetween, and sandwiched on both sides by a titanium plate having a lead-out terminal, impregnated with an electrolytic solution, and sealed as in Example 1. In the electrolyte, a mixed solvent of ethylene carbonate: dimethyl carbonate = 1: 2 (volume ratio) was mixed with L.
The iPF ₆ was used at a concentration of 1M.

Otherwise, the procedure of Example 1 was followed to obtain a capacitor 1. Further, capacitors 2 and comparative capacitors 1 were produced in the same manner as in Example 2 and Comparative Example 1.

The obtained capacitors 1 and 2 and the comparative capacitor 1 were evaluated in the same manner as in Example 1 except that the charging and discharging operations for the capacitors were performed. FIG. 4 shows the results. FIG.
As is clear from the graph, as a result of the improvement in the hermeticity according to the present invention, the charge / discharge cycle life of the capacitor was significantly improved.

[0072]

As described above, according to the electrochemical device of the present invention, cycle life and high-temperature storage characteristics can be improved.

Further, according to the method for manufacturing an electrochemical device of the present invention, such an electrochemical device can be reliably manufactured.

[Brief description of the drawings]

FIG. 1 shows the structure of the electrochemical device of the present invention,
(A) is a plan view showing electrodes and lead-out terminals constituting an electrochemical element, (b) is a plan view showing an outer bag, and (c) is an electrochemical device formed by enclosing the electrochemical element in an outer bag. FIG.

FIG. 2 is a sectional view taken along line AA of FIG. 1 (c).

FIG. 3 is a graph showing the change in the charge / discharge capacity of the lithium ion secondary batteries of Examples and Comparative Examples with respect to the number of times of charge / discharge.

FIG. 4 is a graph showing a change in charge / discharge capacity of an electric double layer capacitor according to an example and a comparative example with respect to the number of times of charge / discharge.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrochemical device 10 Electrochemical element 11, 12 Electrode 13, 14 Lead-out terminal 13a, 14a Seal part 20 Outer bag 21 First seal part 22 Second seal part 30 Laminate film 40 Intermediate layer 41 Metal-resin adhesive layer 42 Polyolefin resin layer

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H011 AA17 CC02 CC06 CC10 DD13 EE04 FF04 GG08 HH02 5H029 AJ04 AJ05 AK03 AK06 AK07 AL06 AL12 AM00 AM02 AM03 AM04 AM05 AM07 AM16 BJ04 CJ05 CJ13 CJ22 DJ02 DJ03 DJ05 DJ09 DJ09

Claims (7)

[Claims] 1. An electrochemical device having an outer bag and an electrochemical element sealed in the outer bag, wherein the outer bag is a laminate film having a metal layer and a heat-adhesive resin layer, The electrochemical device has a lead-out terminal that is sealed and sealed by a heat-sealed seal portion between the heat-adhesive resin layers of the outer bag, and is led out through the seal portion. An electrical device comprising: a metal-resin adhesive layer directly laminated on the lead terminal and an olefin resin layer covering the metal-resin adhesive layer between the lead terminal and the outer bag. Chemical device. 2. The electrochemical device according to claim 1, wherein the electrochemical device has both positive and negative electrodes and a solid polymer electrolyte. 3. The electrochemical device according to claim 1, which is a lithium secondary battery. 4. The electrochemical device according to claim 1, which is an electric double layer capacitor. 5. An electrochemical device is housed in an outer bag, which is a laminate film having a metal layer and a heat-adhesive resin layer, and a lead terminal connected to both positive and negative electrodes of the electrochemical device.
A method for manufacturing an electrochemical device in which a seal portion is formed by thermal bonding between thermal adhesive resin layers of the outer package and sealed, and a portion corresponding to the seal portion of the lead terminal is provided from the lead terminal side. A lead terminal coating step of thermally bonding with an intermediate layer laminated in the order of a metal-resin adhesive layer and a polyolefin resin layer, and a polymer film between the positive and negative electrodes of the electrochemical device after the lead terminal coating step is completed. A process of injecting an electrolyte to obtain a solid polymer electrolyte; and a step of enclosing the electrochemical element after the injecting step in the outer bag with the sealing portion. Method. 6. The metal-resin adhesive layer is formed by applying a metal-resin adhesive to a portion of the lead terminal corresponding to the seal portion, wherein the metal-resin adhesive layer is formed. The method for producing an electrochemical device according to claim 5, wherein a polyolefin resin film is thermally bonded onto the inter-adhesive layer. 7. The lead-out terminal covering step includes: bonding a fusion sheet having a metal-resin adhesive layer and a polyolefin resin layer to a portion corresponding to the seal portion of the lead-out terminal; 6. The method for manufacturing an electrochemical device according to claim 5, wherein a layer is arranged on the side of the lead-out terminal and thermally bonded.