CN1929187A - Battery with a battery cell - Google Patents

Abstract

Provided is a battery in which the relative positions of a positive electrode, a negative electrode, and a separator are maintained with high accuracy. The positive electrode and the negative electrode are opposed to each other with a polymer electrolyte including a polymer and a separator in between. In each of the positive electrode and the negative electrode, an active material layer is disposed on a current collector. The exposed region where the active material layer is not disposed on the current collector and the separator are adhered to each other with the polymer electrolyte in between. Thus, even under a high-temperature environment, thermal shrinkage of the separator can be prevented, and heat generation due to generation of a short-circuit current can be prevented.

Description

Battery

Cross References to Related Applications

The present invention contains subject matter related to Japanese Patent Application JP2005-262494 filed in the Japan Patent Office on September 9, 2005 and JP2006-149242 filed in the Japan Patent Office on May 30, 2006, the entire contents of which are hereby incorporated by reference as refer to.

technical field

The present invention relates to batteries using polymer electrolytes including polymers.

Background technique

In recent years, a large number of portable electronic devices such as camcorders, cellular phones and portable computers have appeared, and attempts have been made to reduce their size and weight. Therefore, the development of batteries, particularly secondary batteries, as portable power sources for electronic equipment has been actively promoted. Among them, lithium ion secondary batteries have attracted attention as batteries capable of obtaining high energy density.

In such a lithium ion secondary battery, a battery case made of a metal such as aluminum (Al) or iron (Fe) is used as a packaging member. Recently, a laminated film is used instead of a battery case made of metal as a packaging member, resulting in a further reduction in size, weight, and appearance of the battery (for example, see Japanese Unexamined Patent Application Publication Nos. 2003-217674 and H6-150900).

Contents of the invention

However, the laminated film has lower rigidity than a packaging member made of metal such as aluminum or iron, and thus the laminated film has a small force pressing on the battery elements in the battery. The battery element is a laminate including a positive electrode and a negative electrode with a separator in between. Therefore, in a battery in which the packaging member is a laminated film, application of an external force may cause relative displacement between the positive electrode, the negative electrode, and the separator in the battery element, whereby the positive electrode and the negative electrode may be short-circuited. When the area of the separator is sufficiently larger than that of the electrodes, contact between the positive and negative electrodes can be prevented even if relative displacement occurs; however, in this case, since the additional separator is included, the active material in the battery can be filled The amount decreases, thereby reducing the energy density.

In view of the above, it is desirable to provide a battery in which the relative positions of the positive electrode, the negative electrode, and the separator are maintained with high precision.

According to an embodiment of the present invention, there is provided a battery including: a positive electrode and a negative electrode in a film-like packaging member, the positive electrode and the negative electrode are opposed to each other with a polymer electrolyte and a separator in between, the polymer electrolyte comprising a polymer , wherein the active material layer is arranged on a current collector in at least one of the positive electrode and the negative electrode, and the exposed area on the current collector where the active material layer is not arranged and the separator are at least partially adhered to each other through the polymer electrolyte in between attached.

In the battery according to this embodiment of the present invention, part of the separator is adhered to the exposed area of the current collector in at least one of the positive electrode and the negative electrode through the polymer electrolyte, whereby the opposite of the separator to at least one of the positive electrode and the negative electrode The position is fixed.

In the battery according to this embodiment of the present invention, the exposed area of the current collector and the separator are adhered to each other with the polymer electrolyte including the polymer in between, whereby the relative positions of the positive electrode, the negative electrode, and the separator can be maintained with high precision . Thereby, contact between the positive electrode and the negative electrode can be prevented, and heat generation due to generation of short-circuit current can be prevented.

In particular, when the peel strength when the exposed area and the separator are peeled off from each other is 5 mN/mm or more, the adhesive force becomes higher, and thus a higher effect can be obtained.

Also, when the polymer includes a polymer containing vinylidene fluoride as a component, a higher effect can be obtained.

In addition, when the thickness of the polymer electrolyte is 1 μm or more, a higher effect can be obtained.

Other and further objects, features and advantages of the invention will appear more fully from the following description.

Description of drawings

1 is an exploded perspective view of the structure of a secondary battery according to a first embodiment of the present invention;

Figure 2 is a cross-sectional view of the battery element along the line I-I of Figure 1;

3 is a diagram describing a method of measuring peel strength in Examples;

4 is an exploded perspective view of the structure of a secondary battery according to a second embodiment of the present invention;

Figure 5 is a top view of the battery element shown in Figure 4;

6 is a cross-sectional view of the battery element along the line VI-VI of FIG. 5;

7 is a plan view of a positive electrode included in the battery element shown in FIG. 4;

8 is a plan view of a negative electrode included in the battery element shown in FIG. 4; and

9A, 9B and 9C are diagrams showing steps in a method of manufacturing the secondary battery shown in FIG. 5 .

Detailed ways

Preferred embodiments will be described in detail below with reference to the accompanying drawings.

[first embodiment]

FIG. 1 shows the structure of a secondary battery 1 according to a first embodiment of the present invention. The secondary battery 1 is particularly a so-called laminated film-type wound type, and in the secondary battery 1, the wound type battery element 20 to which the positive terminal 11 and the negative terminal 12 are attached is contained in a film-like packaging member 30 middle.

The positive terminal 11 and the negative terminal 12 are drawn from the inside to the outside of the packaging member 30, for example, in the same direction. The positive terminal 11 and the negative terminal 12 are made of, for example, a sheet-shaped or mesh-shaped metal material such as aluminum, copper (Cu), nickel (Ni), or stainless steel.

The packing member 30 is made of, for example, a rectangular aluminum laminated film including a nylon film, an aluminum foil, and a polyethylene film, bonded in this order. The packaging members 30 are arranged such that the polyethylene film of each packaging member 30 faces the battery element 20 and edge portions of the packaging members 30 are adhered to each other by welding or an adhesive. An adhesive film 31 is interposed between the packaging member 30 and the positive terminal 11 and the negative terminal 12 to prevent entry of external air. Adhesive film 31 is made of, for example, a material having adhesion to positive terminal 11 and negative terminal 12 , for example, polyolefin resin such as polyethylene, polypropylene, modified polyethylene, or modified polypropylene.

In addition, the packaging member 30 may be made of a laminated film having any other structure, a high molecular weight film such as polypropylene, or a metal film instead of the above-mentioned aluminum laminated film.

FIG. 2 shows a cross-sectional view of the battery element 20 along line I-I of FIG. 1 . The battery element 20 is a spirally wound element in which a positive electrode 21 and a negative electrode 22 face each other with a polymer electrolyte 23 and a separator 24 in between, and the outermost portion of the battery element 20 is protected with a protective tape 25 .

The positive electrode 21 has a structure in which an active material layer 21B is arranged on one or both faces of a current collector 21A having a pair of opposing faces. Collector 21A has exposed region 21C in which active material layer 21B is not arranged at the end portion in the longitudinal direction. The positive terminal 11 is attached to the exposed region 21C. Current collector 21A is made of, for example, metal foil such as aluminum foil, nickel foil, or stainless foil.

The active material layer 21B includes, for example, one or two or more positive electrode materials capable of inserting and extracting lithium (Li) as an electrode reactant as a positive electrode active material, and if necessary, the active material layer 21B includes an electric conductor and a binder .

As a positive electrode material capable of inserting and extracting lithium, for example, chalcogenides not including lithium such as titanium sulfide (TiS ₂ ), molybdenum sulfide (MoS ₂ ), niobium selenide (NbSe ₂ ) or vanadium oxide (V ₂ O ₅ ), or lithium-containing compounds, or polymers such as polyacetylene or polypyrrole.

Among them, lithium-containing compounds are preferable because lithium-containing compounds can obtain high voltage and high energy density. As such a lithium-containing compound, for example, a composite oxide containing lithium and a transition metal element, or a phosphate compound containing lithium and a transition metal element is cited, and in particular, preferably contains a compound selected from cobalt (Co), nickel, manganese ( A lithium-containing compound of at least one of Mn) and iron because higher voltages can be obtained. The chemical formula of the lithium-containing compound is represented by, for example, Li _x MIO ₂ or Li _y MIIPO ₄ . In the formula, MI and MII represent one or more transition metal elements. In the formula, the values of x and y depend on the charge-discharge state of the battery, and are generally in the ranges of 0.05≤x≤1.10 and 0.05≤y≤1.10, respectively.

Specific examples of composite oxides containing lithium and a transition metal element include lithium-cobalt composite oxide (Li _x CoO ₂ ), lithium-nickel composite oxide (Li _x NiO ₂ ), lithium-nickel-cobalt composite oxide (Li _{x Niz} Co _1-z O ₂ (0<z<1)), lithium-manganese composite oxide (LiMn ₂ O ₄ ) having a spinel structure, and the like. Specific examples of phosphate compounds containing lithium and transition metal elements include lithium-iron phosphate compounds (LiFePO ₄ ) and lithium-iron-manganese phosphate compounds (LiFe _1-v Mn _v PO ₄ (V<1)).

As in the case of the positive electrode 21 , the negative electrode 22 has a structure in which an active material layer 22B is arranged on one or both faces of a current collector 22A having a pair of opposing faces. The current collector 22A has an exposed region 22C in which the active material layer 22B is not arranged at the end in the longitudinal direction, and the negative electrode terminal 12 is attached to the exposed region 22C. Current collector 22A is made of, for example, metal foil such as copper foil, nickel foil, or stainless foil.

The active material layer 22B includes, as an anode active material, one or two or more anode materials capable of inserting and extracting lithium as an electrode reactant, for example, and if necessary, the active material layer 22B includes an electric conductor and a binder.

As the negative electrode material capable of inserting and extracting lithium, for example, carbon materials, metal oxides, and polymers are cited. As the carbon material, non-graphitizable carbon materials, graphite materials, etc. are listed, and more specifically, pyrolytic carbons, cokes, graphites, glassy carbons, calcined high-molecular-weight organic compound bodies, carbon fibers, Activated carbon, etc. Among them, the cokes include pitch coke, needle coke, petroleum coke, etc., and the calcined high-molecular-weight organic compound body is a polymer such as phenolic resin and furan resin that is carbonized by calcining at an appropriate temperature. Also, metal oxides include iron oxide, ruthenium oxide, molybdenum oxide, and the like, and polymers include polyacetylene, polypyrrole, and the like.

As the negative electrode material capable of inserting and extracting lithium, a material including at least one selected from a metal element and a metalloid element capable of forming an alloy with lithium is exemplified. The negative electrode material may be a single substance, an alloy or a compound of a metal element or a metalloid element, or a material including at least part of a phase containing one or two or more thereof. In the present invention, an alloy refers to an alloy including two or more metal elements and an alloy including one or more metal elements and one or more metalloid elements. Also, alloys may include non-metallic elements. As the texture of the alloy, a solid solution, a eutectic (eutectic mixture), an intermetallic compound, or a coexistence of two or more selected from them is cited.

Such metal elements and metalloid elements include, for example, tin (Sn), lead (Pb), aluminum, indium (In), silicon (Si), zinc (Zn), antimony (Sb), bismuth (Bi), gallium (Ga ), germanium (Ge), arsenic (As), silver (Ag), hafnium (Hf), zirconium (Zr), and yttrium (Y). Among them, Group 14 metal elements or Group 14 metalloid elements in the long-period periodic table are preferable, and in particular, silicon or tin are preferable because silicon and tin have a high ability to intercalate and deintercalate lithium and obtain high energy density.

As a tin alloy, for example, include at least one selected from the group consisting of silicon, nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium (Ti), germanium, bismuth, antimony, and chromium (Cr). Tin alloys with the second constituent element outside. As a silicon alloy, for example, there are listed, as a second constituent element other than silicon, at least one selected from the group consisting of tin, nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium, germanium, bismuth, antimony, and chromium. silicon alloy.

As the compound of tin or silicon, for example, a compound including oxygen (O) or carbon (C) is cited, and the compound may include the above-mentioned second constituent element in addition to tin or silicon.

The polymer electrolyte 23 includes an electrolytic solution and a polymer holding the electrolytic solution, and is a so-called gel electrolyte. The electrolytic solution includes, for example, a solvent and an electrolytic salt dissolved in the solvent. The polymer electrolyte 23 may not hold the entire electrolyte solution. For example, the cathode 21, the anode 22, and the separator 24 may be impregnated with some electrolyte solution.

Examples of the solvent include lactone-based solvents such as γ-butyrolactone, γ-valerolactone, δ-valerolactone, or ε-caprolactone, carbonate-based solvents such as ethylene carbonate, propylene carbonate, Butylene carbonate, dimethyl carbonate, ethyl methyl carbonate or diethyl carbonate, ether-based solvents such as 1,2-dimethoxyethane, 1-ethoxy-2-methoxyethane, 1 , 2-diethoxyethane, tetrahydrofuran or 2-methyltetrahydrofuran, nitrile-based solvents such as acetonitrile, sulfolane-based solvents, phosphoric acid, phosphate ester solvents, and nonaqueous solvents such as pyrrolidone. As the solvent, one kind or a mixture of two or more kinds selected from them can be used.

As the electrolyte salt, any salt that dissolves in a solvent and generates ions can be used, and one or a mixture of two or more selected from these salts can be used. Examples of lithium salts include lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), lithium hexafluoroarsenate (LiAsF ₆ ), lithium perchlorate (LiClO ₄ ), lithium trifluoromethanesulfonate (LiCF ₃ SO ₃ ), lithium bis(trifluoromethanesulfonyl)imide (LiN(SO ₂ CF ₃ ) ₂ ), tris(trifluoromethanesulfonyl)methyllithium (LiC(SO ₂ CF ₃ ) ₃ ), tetrachloroaluminum Lithium oxide (LiAlCl ₄ ), lithium hexafluorosilicate (LiSiF ₆ ), etc. Among them, lithium hexafluorophosphate or lithium tetrafluoroborate is preferable in terms of oxidation stability.

The concentration of the electrolyte salt in the electrolyte solution is preferably in the range of 0.1 mol to 3.0 mol per liter (l) of solvent, and more preferably in the range of 0.5 mol to 2.0 mol, because in this range, good ion conductivity can be obtained .

As the polymer, for example, a polymer including vinylidene fluoride as a component is cited. More specifically, a copolymer including polyvinylidene fluoride or vinylidene fluoride as a component is cited. Specific examples of copolymers include vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-chlorotrifluoroethylene copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer, Vinyl fluoride copolymer, vinylidene fluoride-hexafluoropropylene-chlorotrifluoroethylene copolymer, or any of the above-mentioned copolymers copolymerized with other ethylenically unsaturated monomers.

Examples of polymers include polyacrylonitrile, polyethylene oxide, polymethyl methacrylate, polyvinyl chloride, and derivatives thereof. As the polymer, one kind or a mixture of two or more kinds selected from them can be used.

The separator 24 is made of, for example, an insulating film having a high ion permeability and a predetermined mechanical strength such as a porous film based on a polyolefin material such as polypropylene or polyethylene, or a porous film of an inorganic material such as a ceramic non-woven fabric. , and the separator 24 may have a structure in which two or more porous films are laminated.

The separator 24 adheres to the active material layers 21B and 22B with the polymer electrolyte 23 in between. Also, at least part of the separator 24 adheres to the exposed region 21C of the current collector 21A and the exposed region 22C of the current collector 22A with the polymer electrolyte 23 in between. Thereby, the relative positions of the cathode 21 , the anode 22 , and the separator 24 can be maintained even if some external force is applied from the outside of the packaging member 31 . Also, thermal shrinkage of the diaphragm 24 can be prevented even under a high-temperature environment. Therefore, heat generation caused by a short-circuit current generated by the contact of the current collector 21A and the current collector 22A can be prevented. In particular, in a region where the positive electrode 21 and the negative electrode 22 face each other with the separator 24 in between, the entire surfaces of the positive electrode 21 and the negative electrode 22 are preferably adhered to the separator 24 through the polymer electrolyte 23 because higher Effect. Also, as the polymer of the polymer electrolyte 23, a copolymer including vinylidene fluoride as a component is preferably used because a higher effect can be obtained. In addition, the thickness of the polymer electrolyte 23 is preferably 1 μm or more because when the thickness is too small, the adhesive force decreases.

The peel strength when the exposed regions 21C and 22C and the separator 24 adhered together via the polymer electrolyte 23 in between are peeled off from each other is preferably 5 mN/mm or more because the adhesive force between them is high, and Heat generation due to generation of short-circuit current can be further prevented. Also, the peel strength when the positive electrode active material layer 21B or the negative electrode active material layer 22B and the separator 24 are peeled off from each other is preferably in the same range because an increase in resistance in the interface according to charge and discharge can be prevented.

For example, secondary battery 1 can be manufactured through the following steps.

First, the active material layer 21B is formed on the current collector 21A, thereby forming the positive electrode 21 . The active material layer 21B is formed through the following steps. Powder of a positive electrode active material, an electrical conductor, and a binder are mixed to form a positive electrode mixture, which is then dispersed in a solvent such as N-methyl-2-pyrrolidone to form a paste positive electrode mixture slurry. The positive electrode mixture slurry was coated on the current collector 21A, and the positive electrode mixture slurry was dried and compression molded, thereby forming the active material layer 21B. Also, as in the case of the positive electrode 21 , the negative electrode 22 is formed by forming the active material layer 22B on the current collector 22A.

Next, the positive terminal 11 is attached to the exposed region 21C of the current collector 21A, and the negative terminal 12 is attached to the exposed region 22C of the current collector 22A. The positive electrode 21 and the negative electrode 22 are laminated with the separator 24 in between to form a laminate, and the laminate is spirally wound in the longitudinal direction, and the protective tape 25 is adhered to the outermost part of the laminate, thereby forming the spiral wound Around the electrode body. At this time, a high-molecular-weight solution formed by dissolving a polymer in a solvent such as N-methyl-2-pyrrolidone is coated on the separator 24, and the high-molecular-weight solution is dried to remove the solvent, thereby forming a polymer on the separator 24. Precursor layer of electrolyte 23 . The high molecular weight solution may be coated on the positive electrode 21 or the negative electrode 22 without being coated on the separator 24 . Next, the spirally wound electrode body is sandwiched between the package members 30, and the edge portion of the package member 30 except one side is adhered by heat welding, the electrolytic solution is injected into the package member 30, and then the remaining Edge portions on the sides are adhered by heat welding to seal the electrolytic solution in the packaging member 30 . After that, if necessary, the electrolytic solution is held by the polymer by applying heat to form the polymer electrolyte 23, thereby completing the secondary battery 1 shown in FIGS. 1 and 2 . At this time, the adhesion strength between the exposed region 21C or the exposed region 22C and the separator 24 can be controlled by appropriately changing heating conditions or the like or applying pressure.

When the secondary battery 1 is charged, lithium ions are extracted from the positive electrode 21 and inserted into the negative electrode 22 through the electrolytic solution. On the other hand, when the secondary battery 1 is discharged, for example, lithium ions are extracted from the negative electrode 22 and inserted into the positive electrode 21 through the electrolytic solution. In this case, the exposed region 21C of the current collector 21A or the exposed region 22C of the current collector 22A and the separator 24 are firmly adhered together with the polymer electrolyte 23 in between, so even when some external force is applied It is also difficult to move the relative positions of the positive electrode 21, the negative electrode 22, and the separator 24, and thermal shrinkage of the separator 24 can be prevented even in a high-temperature environment.

Therefore, in the present embodiment, the exposed region 21C of the collector 21A or the exposed region 22C of the collector 22A and the separator 24 are adhered together by the polymer electrolyte 23 including a polymer in the middle, so that the separator 24 can be reduced. 24 on the external force or thermal load, and can prevent heat caused by short-circuit current. At this time, the size of the separator 24 occupying the inside of the battery can be minimized, so that it is not necessary to reduce the total amount of active materials, and it is advantageous to ensure high energy density.

In particular, when the peel strength when the exposed regions 21C and 22C and the separator 24 are peeled off from each other is 5 mN/mm or more, the adhesive force becomes larger, and thus a higher effect can be obtained.

Also, when the polymer includes a polymer containing vinylidene fluoride as a component, the adhesive force becomes greater, and thus a higher effect can be obtained.

In addition, when the thickness of the polymer electrolyte 23 is 1 μm or more, the adhesive force becomes larger, so a higher effect can be obtained.

[Second Embodiment]

FIG. 4 shows the structure of a secondary battery 2 according to a second embodiment of the present invention. The secondary battery 2 is particularly a so-called laminated film type, and in the secondary battery 2 , the laminated battery element 50 to which the positive terminal 41 and the negative terminal 42 are attached is contained in a film-like packaging member 61 .

The positive terminal 41 and the negative terminal 42 take out the electromotive force generated in the laminated battery element 50 to the outside, and each of the positive terminal 41 and the negative terminal 42 has a strip shape. They lead from the inside to the outside of the packaging member 61, for example, in the same direction. The positive terminal 41 and the negative terminal 42 have the same structures as the positive terminal 11 and the negative terminal 12 in the secondary battery 1 shown in FIG. 1 , respectively. The adhesive film 62 is interposed between the packaging member 61 and the positive terminal 41 and the negative terminal 42 to prevent entry of external air. The packaging member 61 and the adhesive film 62 have the same structures as the packaging member 30 and the adhesive film 31 in the secondary battery 1, respectively.

FIG. 5 shows a top view of the appearance of the battery element 50 shown in FIG. 4 , and FIG. 6 shows a cross-sectional view along line VI-VI of FIG. 5 . A laminated battery element 50 is formed by alternately stacking positive electrodes 51 and negative electrodes 52 with a separator 54 in between.

FIG. 7 shows the structure of a positive electrode 51 viewed from the lamination direction. The positive electrode 51 has a rectangular coating region 51D in which active material layers 51B are arranged on both faces of a collector 51A. An exposed area 51C (which will be a strap terminal attachment portion) protrudes from one corner of the coated area 51D. In exposed region 51C, active material layer 51B is not arranged, current collector 51A is exposed, and positive terminal 41 (refer to FIG. 4 ) is bonded to exposed region 51C. In FIGS. 5 and 6 , the state before the positive terminal 41 is bonded is shown.

FIG. 8 shows the structure of one negative electrode 52 viewed from the lamination direction. As in the case of the positive electrode 51, the negative electrode 52 has an area in which an exposed region 52C (which will be a tape-shaped terminal attachment portion) protrudes from one corner of a rectangular coating region 52D in which an active material layer 52B is arranged on both faces of a current collector 52A. structure. In the exposed region 52C, the active material layer 52B is not arranged, the current collector 52A is exposed, and the negative electrode terminal 42 (refer to FIG. 4 ) is bonded to the exposed region 52C. In FIGS. 5 and 6 , the state before the negative terminal 42 is joined is shown.

As shown in FIGS. 4 and 5 , the exposed region 51C and the exposed region 52C are arranged so as not to overlap each other in the lamination direction A of the battery element 50 (direction perpendicular to the sheet of FIG. 5 ). Also, the negative electrode 52 is formed to be larger than the positive electrode 51, and the relative positions of the positive electrode 51 and the negative electrode 52 are adjusted so that the coating region 51D fits inside the coating region 52D when viewed from the stacking direction A. In the case where the coating area 51D is not fitted inside the coating area 52D, a portion not facing the coating area 51D (a portion protruding from the coating area 51D) is formed at the end of the coating area 52D. Therefore, at the time of charging, it is considered that the area of the negative electrode 52 for receiving lithium ions extracted from the positive electrode 51 is not large enough (ie, the current density at the end of the negative electrode 52 increases), whereby metal lithium dendrites may be deposited. Such deposition of metallic lithium dendrites can lead to capacity loss, or internal short circuit due to destruction of the separator 54 , so in order to prevent deposition of metallic lithium dendrites, the above-described structure is used in the present embodiment. The lithium insertion capacity per unit area of the active material layer 52B is set so as not to exceed the lithium extraction capacity per unit area of the active material layer 51B.

With the polymer electrolyte 53 in between, the separator 54 is adhered to the active material layers 51B and 52B occupying the coating regions 51D and 52D (refer to FIG. 6 ). In overlapping portion 51E of exposed region 51C and overlapping portion 52E of exposed region 52C, separator 54 is further adhered to collectors 51A and 52A with polymer electrolyte 53 in between (refer to FIGS. 5 and 6 ). In other words, the overlapping portions 51E and 52E are adhesion regions. Thereby, the relative positions of the cathode 51 , the anode 52 , and the separator 54 can be maintained even if some external force is applied from the outside of the packaging member 61 .

Also, the separator 54 has a larger area than the regions in which the active material layers 52A and 52B are formed in the positive electrode 51 and the negative electrode 52 (ie, the coating regions 51D and 52D), and the edge portion 54B of the separator 54 passes through the polymer electrolyte in the middle. 53 are adhered together to enclose coated areas 51D and 52D. Accordingly, the separator 54 is formed into a bag shape to wrap each of the positive electrode 51 and the negative electrode 52 . Thereby, even in the case of a high-temperature environment, heat shrinkage of the separator 54 can be prevented, and heat generation caused by a short-circuit current generated by contact between the current collector 51A and the current collector 52A can be prevented.

For example, secondary battery 2 can be manufactured through the following steps.

First, for example, a positive electrode active material, an electrical conductor, and a binder are mixed to form a positive electrode mixture, and the positive electrode mixture is dispersed in a solvent such as N-methyl-2-pyrrolidone to form a positive electrode mixture slurry. Next, as shown in FIG. 9A , the positive electrode mixture slurry is coated on both sides of a strip-shaped metal foil 51AZ made of, for example, aluminum foil or the like, and the positive electrode mixture slurry is dried and compression molded to form an active material film 51BZ. At this time, active material film 51BZ is formed only on coating portion 51DZ which will become coating region 51D in metal foil 51AZ, and active material film 51BZ is not formed on exposed portion 51CZ which will become exposed region 51C. Also, the position of the coating portion 51DZ is substantially the same on both sides of the metal foil 51AZ.

Next, as shown in FIG. 9A , the metal foil 51AZ on which the active material film 51BZ is formed is cut along dotted lines X1 and X2 and dotted lines Y1 to Y3 to form four rectangular electrode plates 51Z. The number of electrode plates 51Z formed at one time is not limited to 4, and may be appropriately selected.

Further, as shown in FIG. 9B , the electrode plate 51Z is cut along a dotted line 51L to form four positive electrodes 51 having a predetermined shape as shown in FIG. 9C .

As in the case of the positive electrode 21, the negative electrode 52 is formed. More specifically, first, a negative electrode active material and a binder are mixed to form a negative electrode mixture, and the negative electrode mixture is dispersed in a solvent such as N-methyl-2-pyrrolidone to form a negative electrode mixture slurry. Then, the negative electrode mixture slurry is coated on both sides of a strip-shaped metal foil 52AZ made of copper foil or the like, and the negative electrode mixture slurry is dried and compression molded to form an active material film 52BZ. At this time, as in the case of the positive electrode 51, the active material film 52BZ is formed only on the coated portion 52DZ which will become the coated region 52D in the metal foil 52AZ, and the active material film 52BZ is not formed on the exposed area which will become the exposed region 52C. Part 52CZ on. Also, the position where the coating portion 52DZ is formed is substantially the same on both sides of the metal foil 52AZ. In other words, the coating ends of the coating zone 52DZ are positioned on substantially the same line on both sides.

Next, as shown in FIG. 9A , metal foil 52AZ on which active material film 52BZ is formed is cut along dotted lines X1 and X2 and dotted lines Y1 to Y3 , and as shown in FIG. 9B , metal foil 52AZ is further cut along dotted line 52L. Thereby, as shown in FIG. 9C , four negative electrodes 52 having a predetermined shape are completed.

When the active material layer 51B and the active material layer 52B are formed, the capacity of intercalating lithium per weight of the negative electrode mixture and the capacity of extracting lithium per weight of the positive electrode mixture are measured in advance, and the capacity of intercalating lithium per unit area of the active material layer 52B is set so that no The capacity to extract lithium per unit area of the negative electrode material layer 51B is exceeded.

After forming the cathode 51 and the anode 52 , the separator 54 was prepared, which was cut into a rectangular shape so as to have a larger area than the coating regions 51D and 52D in the cathode 51 and the anode 52 . After that, three positive electrodes 51, four negative electrodes 52, and six separators 54 are used to form a laminated battery element 50, wherein the negative electrode 52, separator 54, positive electrode 51, separator 54, negative electrode 52, separator 54, positive electrode 51, separator 54, Negative electrode 52 , separator 54 , positive electrode 51 , separator 54 and negative electrode 52 are in sequence, as shown in FIG. 6 . At this time, the relative positions of the positive electrode 51 and the negative electrode 52 are adjusted so that the exposed area 51C and the exposed area 52C do not overlap each other while the coated area 51D fits inside the coated area 52D when viewed from the stacking direction A. The precursor layer of polymer electrolyte 53 may be formed in advance by applying a high molecular weight solution formed by dissolving a polymer in a solvent such as N-methyl-2-pyrrolidone to separator 54 and drying the high molecular weight solution to remove the solvent. Alternatively, the above-mentioned high molecular weight solution may be coated on the positive electrode 51 or the negative electrode 52 in advance, but not on the separator 54 .

Thus, stacked battery element 50 using active material layer 51B, separator 54 , and active material layer 52B as a standard stacked unit is formed, and active material layer 52B is arranged on both ends of stacked battery element 50 in stacking direction A.

After the battery element 50 is formed, the exposed regions 51C of the three positive electrodes 51 are attached to the positive terminal 41 at a time (refer to FIG. 4 ). Likewise, exposed regions 52C of four negative electrodes 52 are attached to the negative electrode terminal 42 at a time. They are attached by, for example, ultrasonic welding.

After attaching the positive terminal 41 and the negative terminal 42, the laminated battery element 50 is impregnated with an electrolytic solution, and the laminated battery element 50 is sandwiched between the packaging members 61, and then the edge portion of the packaging member 61 is bonded by heat welding or the like. Attached to seal the battery element 50. At this time, the adhesive film 62 is inserted between the positive terminal 41 and the negative terminal 42 and the packaging member 61 . After that, if necessary, heat is applied to keep the polymer in the electrolytic solution, thereby forming the polymer electrolyte 53 . At this time, the adhesion strength of the polymer electrolyte 53 can be controlled by changing heating conditions or applying pressure as necessary. Thus, secondary battery 2 shown in FIG. 4 is completed.

In the secondary battery 2, the exposed region 51C of the collector 51A or the exposed region 52C of the collector 52A and the separator 54 are firmly adhered to each other through the polymer electrolyte 53 in between, so even when some external force is applied Also, it is difficult to move the relative positions of the positive electrode 51, the negative electrode 52, and the separator 54. Also, the area of the diaphragm 54 is larger than that of the coating regions 51D and 52D, and the edge portions 54B are adhered to each other, so thermal shrinkage of the diaphragm 54 can be prevented even in a high temperature environment. Thus, in the secondary battery 2, the influence of external force on the separator 54 or the influence of heat load can be reduced, and heat generation caused by generation of short-circuit current can be prevented.

[Example]

Specific embodiments of the present invention will be described in detail below

(Examples 1-1 to 1-3)

The secondary battery 1 shown in FIGS. 1 and 2 was formed.

First, 0.5 mol of lithium carbonate and 1 mol of cobalt carbonate were mixed to form a mixture, and the mixture was fired at 900° C. for 5 hours in air to synthesize lithium-cobalt composite oxide (LiCoO ₂ ) as a positive electrode active material. Next, 85 parts by weight of lithium-cobalt composite oxide powder, 5 parts by weight of graphite powder as an electrical conductor, and 10 parts by weight of polyvinylidene fluoride as a binder were mixed to form a positive electrode mixture, which was then dispersed in N-methyl-2-pyrrolidone as a solvent to form a positive electrode mixture slurry.

Next, the positive electrode mixture slurry was uniformly coated on both sides of the current collector 21A made of 20 μm thick aluminum foil so that both ends of the current collector 21A were exposed, the positive electrode mixture slurry was dried, and passed through a roller press Compression molding was performed to form the active material layer 21B and the exposed region 21C, thereby forming the belt-shaped positive electrode 21 . After that, the positive terminal 11 is attached to the exposed region 21C.

In addition, powdered graphite powder was used as the negative electrode active material, and 90 parts by weight of graphite powder, 10 parts by weight of polyvinylidene fluoride as a binder were mixed to form a negative electrode mixture, and then the negative electrode mixture was dispersed in N-methyl-2-pyrrolidone to form negative electrode mixture slurry.

Next, the negative electrode mixture slurry was uniformly coated on both surfaces of the current collector 22A made of 15 μm thick copper foil so that both ends of the current collector 22A were exposed, the negative electrode mixture slurry was dried, and compression molded To form the active material layer 22B and the exposed region 22C, thereby forming the belt-shaped negative electrode 22 . After that, the negative terminal 12 is attached to the exposed area 22C.

Next, polyvinylidene fluoride was prepared as a polymer, and polyvinylidene fluoride was dissolved in N-methyl-2-pyrrolidone as a solvent to form a high molecular weight solution. The content of polyvinylidene fluoride in the high molecular weight solution was 15% by weight. Next, after applying the high-molecular-weight solution to the separator 24 made of a microporous polyethylene film with a thickness of 20 μm by using a coating device, the separator 24 coated with the high-molecular-weight solution was impregnated with deionized water, The membrane 24 is then dried. Thus, a precursor layer of the polymer electrolyte 23 is formed. The high molecular weight solution was completely coated on only one side of the membrane 24 in Examples 1-1 and 1-2, and was completely coated on both sides of the membrane 24 in Example 1-3.

After that, the formed cathode 21 and the formed anode 22 were adhered to each other through the intermediate separator 24 on which the precursor layer was formed, and they were spirally wound in the longitudinal direction to form a spirally wound electrode body. At this time, in Example 1-1, the precursor layer and the negative electrode 22 are adhered to face each other, and in Example 1-2, the precursor layer and the positive electrode 21 are adhered to face each other, and in Example 1-2 3, the precursor layer is adhered to the positive electrode 21 and the negative electrode 22 so as to face the positive electrode 21 and the negative electrode 22. Next, the spirally wound electrode body was sandwiched between packaging members 30 made of a moisture-proof aluminum laminate film, and then the edge portion of the packaging member 30 except one side was adhered by heat welding, and the electrolyte solution Injected into the packaging part 30. As the aluminum laminated film, a laminated film in which a nylon film of 25 μm thick, an aluminum foil of 40 μm thick and a polypropylene film of 30 μm thick were bonded together, and the polypropylene film of the aluminum laminated film was opposed to the spirally wound electrode body was used. As the electrolytic solution, an electrolytic solution formed by dissolving 1 mol/l of LiPF ₆ as an electrolytic salt in a mixed solvent formed by mixing ethylene carbonate and diethyl carbonate at a weight ratio of 3:7 was used . After that, the edge portions of the packaging member 30 on the remaining sides were bonded, and the packaging member 30 was sandwiched between iron plates, and heated at 70° C. for 3 minutes so that the polymer held the electrolyte solution to form a polymer electrolyte 23, and through the polymer electrolyte 23 in the middle, the exposed region 22C or/and the exposed region 21C and the separator 24 are adhered to each other to form the secondary battery 1 shown in FIGS. 1 and 2 . The thickness of the polymer electrolyte 23 is 5 μm.

As Comparative Example 1-1 with respect to Examples 1-1 to 1-3, a secondary battery was formed as in Examples 1-1 to 1-3 except that the precursor layer was not formed on the separator 24 .

The following heating tests were performed on the secondary batteries of Examples 1-1 to 1-3 and Comparative Example 1-1. First, the secondary battery was charged at 23° C. for 2 hours at a constant current of 500 mA and a constant voltage until the upper limit voltage of 4.2 V was reached, and then the secondary battery was discharged at a constant current of 500 mA until the cut-off voltage of 2.5 V was reached. Next, the secondary battery was charged at a constant current of 500 mA and a constant voltage at 23° C. until the upper limit voltage of 4.2 V was reached, and then the secondary battery was placed in a constant temperature bath at 23° C. at a rate of 5° C./min. The rate was ramped up until 150°C or 155°C was reached, then this temperature was held for 1 hour. At this time, it is detected whether the packaging member 30 is broken due to gas generation. The results are shown in Table 1.

In addition, the secondary batteries of Examples 1-1 to 1-3 and Comparative Example 1-1 were charged and then discharged at a constant current and a constant voltage under the same conditions as above. The secondary battery was disassembled, and the exposed regions 21C and 22C and the separator 24 were peeled off from each other in the following manner to examine the peel strength. First, a portion where the peeled region 22C (or exposed region 21C) and the separator 24 are opposed to each other was cut into a piece having a width of 25 mm and a length of 50 mm as a sample. The obtained sample was placed on a support table so that the current collector 22A (or the current collector 21A) was on top, and as shown in FIG. , to peel the current collector 22A (or the current collector 21A) from the separator 24 . The speed of pulling the current collector 22A (or the current collector 21A) was 10 cm/minute. The peel strength is the average value of the force necessary to peel the current collector 22A (or the current collector 21A) between 6 seconds and 25 seconds after starting to pull the current collector 22A (or the current collector 21A). The results are shown in Table 1.

[Table 1] Heating temperature (℃) Peel strength (mN/mm) Breakage of packaged part 30 Exposed Area 22C - Diaphragm 24 Exposed Area 21C - Diaphragm 24 150°C 155°C Example 1-1 70 15.8 - No No Example 1-2 70 - 16.4 No No Example 1-3 70 16.3 15.5 No No Comparative example 1-1 70 - - yes yes

As is apparent from Table 1, in Examples 1-1 to 1-3 in which the exposed region 21C or exposed region 22C and the separator 24 were adhered together through the polymer electrolyte 23, no deterioration of the package member 30 at high temperature was observed. Cracking; however, in Comparative Example 1-1 in which they were not adhered by the polymer electrolyte, cracking of the packaging member 30 at high temperature was observed.

In other words, it was found that when at least one of the exposed region 21C of the current collector 21A and the exposed region 22C of the current collector 22A and the separator 24 adhere to each other with the polymer electrolyte 23 including a polymer in between, even in In high temperature environment, it can also prevent heat generation.

(Example 2-1 to 2-3)

A secondary battery was formed as in Example 1-1, except that the heating temperature at which the exposed region 22C and the separator 24 were adhered to each other with the polymer electrolyte 23 in between was changed. The heating temperature was 75°C in Example 2-1, 65°C in Example 2-2, and 60°C in Example 2-3.

The secondary batteries of Examples 2-1 to 2-3 were subjected to a heating test as in Examples 1-1 to 1-3, and measured when the exposed region 22C and the separator 24 were peeled off from each other. peel strength. The results are shown in Table 2 together with the results of Example 1-1 and Comparative Example 1-1.

[Table 2] Heating temperature (℃) Peel strength between exposed area 22C-separator 24 (mN/mm) Breakage of packaged part 30 150°C 155°C Example 1-1 75 18.7 No No Example 2-1 70 15.8 No No Example 2-2 65 5.1 No No Example 2-3 60 3.9 No yes Comparative example 1-1 70 - yes yes

As is apparent from Table 2, in Examples 1-1, 2-1, and 2-2 in which the peel strength was 5 mN/mm or more, no package parts were observed in the heating tests at 150°C and 155°C 30; however, in Examples 2-3 in which the peel strength was less than 5 mN/mm, rupture of the packaging member 30 was observed in the heating test at 155°C.

In other words, it was found that the peel strength when at least one of the exposed region 21C and the exposed region 22C is peeled from the separator 24 is preferably 5 mN/mm or more.

(Example 3-1, 3-2)

A secondary battery was formed as in Example 1-1, except that as the polymer, a copolymer formed by copolymerizing 91 parts by weight of vinylidene fluoride, 4 parts by weight of hexafluoropropylene, and 5 parts by weight of chlorotrifluoroethylene was used, or poly Other than methyl methacrylate.

The secondary batteries of Examples 3-1 and 3-2 were subjected to a heating test as in Examples 1-1 to 1-3, and were measured by peeling the exposed region 22C and the separator 24 from each other. peel strength. The results are shown in Table 3 together with the results of Example 1-1 and Comparative Example 1-1.

[table 3] high molecular weight compound Peel strength between exposed area 22C-separator 24 (mN/mm) Breakage of packaged part 30 150°C 155°C Example 1-1 polyvinylidene fluoride 15.8 No No Example 3-1 Copolymer of vinylidene fluoride 17.3 No No Example 3-2 Polymethylmethacrylate 6.9 No yes Comparative example 1-1 - - yes yes

As apparent from Table 3, as in Example 1-1, in Examples 3-1 and 3-2 in which a copolymer of vinylidene fluoride or polymethylmethacrylate was used, no to the rupture of the packaging part 30. On the other hand, in the heating test at 155° C., in Example 3-1 in which a copolymer of vinylidene fluoride was used, no rupture of the packaging member 30 was observed; however, in Example 3-1 in which polymethylmethacrylate was used In Example 3-2 of the ester, breakage of the packaging member 30 was observed.

In other words, it was found that even if other polymers were used, when the exposed region 21C of the current collector 21A or the exposed region 22C of the current collector 22A and the separator 24 adhered to each other with the polymer electrolyte 23 including a polymer in between, Prevents heat build-up even in high temperature environments. Furthermore, it was found that a copolymer including vinylidene fluoride as a component is preferably used as the polymer.

(Examples 4-1 to 4-3)

A secondary battery was formed as in Example 1-1, except that the amount of the coated high molecular weight solution was adjusted to change the thickness of the polymer electrolyte 23 . The thickness of the polymer electrolyte 23 is 10 μm, 1 μm or 0.5 μm.

The secondary batteries of Examples 4-1 to 4-3 were subjected to a heating test as in Examples 1-1 to 1-3, and were measured by peeling the exposed region 22C and the separator 24 from each other. peel strength. The results are shown in Table 4 together with the results of Example 1-1 and Comparative Example 1-1.

[Table 4] Thickness of polymer electrolyte 23 (μm) Peel strength between exposed area 22C-separator 24 (mN/mm) Breakage of packaged part 30 150°C 155°C Example 4-1 10 19.1 No No Example 1-1 5 15.8 No No Example 4-2 1 10.2 No No Example 4-3 0.5 5.3 No yes Comparative example 1-1 - - yes yes

As apparent from Table 4, in Examples 1-1, 4-1, and 4-2 in which the thickness of the polymer electrolyte 23 was 1 μm or more, in the heating tests at 150°C and 155°C, no rupture of the packaging member 30; however, in Example 4-3 in which the thickness of the polymer electrolyte 23 was less than 1 μm, in the heating test at 155° C., rupture of the packaging member 30 was observed.

In other words, it was found that the thickness of polymer electrolyte 23 is preferably 1 μm or more.

(Examples 5-1 to 5-3)

Next, secondary battery 2 shown in FIG. 5 is formed through the steps described in the second embodiment.

The same positive electrode mixture slurry and the same negative electrode mixture slurry as in Examples 1-1 to 1-3 were used. In addition, as the current collector 51A, an aluminum foil with a thickness of 20 μm was used, and as the current collector 52A, a copper foil with a thickness of 15 μm was used.

As the high molecular weight solution applied to the separator 54, the same high molecular weight solutions as in Examples 1-1 to 1-3 were used. In this case, after the high-molecular-weight solution was applied to the separator 54 made of a microporous polyethylene film of 20 μm thick by using a coating device, the separator 54 coated with the high-molecular-weight solution was deionized. Water is used for impregnation and then the membrane 54 is dried. Thus, a precursor layer of the polymer electrolyte 53 is formed. At this time, in Example 5-1, the precursor layer is completely formed only on the side of the separator 54 facing the negative electrode 52, and in Example 5-2, the precursor layer is completely formed only on the side of the separator 54. On one side of the positive electrode 51 , and in Example 5-3, the precursor layer was formed on both the side facing the positive electrode 51 and the side facing the negative electrode 52 .

The same electrolytic solutions as in Examples 1-1 to 1-3 were used. The battery element 50 was impregnated with an electrolytic solution and sandwiched between packaging members 61 made of a moisture-proof aluminum laminate film, and then the battery element was sealed by heat welding the opening portion under reduced pressure. At this time, the positive terminal and the negative terminal are drawn outside through the thermally welded portion. As the aluminum laminated film of the packaging member 61, a laminated film formed by laminating and bonding a nylon film with a thickness of 25 μm, an aluminum foil with a thickness of 40 μm, and a polypropylene film with a thickness of 30 μm in this order is used, and the aluminum laminated film has The polypropylene film is opposed to the battery element 50 . After that, the packing member 61 is sandwiched between iron plates and heated at 70° C. for 3 minutes so that the polymer holds the electrolyte solution to form the polymer electrolyte 53 , and through the polymer electrolyte 53 in the middle, the exposed region 52C and diaphragm 54 (embodiment 5-1), exposed region 51C and diaphragm 54 (embodiment 5-2), or exposed region 51C, exposed region 52C and diaphragm 54 (embodiment 5-3) are adhered to each other to form a pattern 4 shows the secondary battery 2 . The thickness of the polymer electrolyte 53 is 5 μm.

As Comparative Example 5-1 with respect to Examples 5-1 to 5-3, a secondary battery 2 was formed as in Examples 5-1 to 5-3 except that the precursor layer was not formed on the separator 54 .

The secondary batteries 2 of Examples 5-1 to 5-3 were subjected to a heating test as in Examples 1-1 to 1-3, and measured by peeling the exposed region 51C and the separator 54 or the exposed region 52C and the separator 54 from each other Peel strength of Examples 5-1 to 5-3. The results are shown in Table 5.

[table 5] Heating temperature (℃) Peel strength (mN/mm) Rupture of packaged part 61 Exposed Area 52C - Diaphragm 54 Exposed Area 51C - Diaphragm 54 150°C 155°C Example 5-1 70 15.4 - No No Example 5-2 70 - 16.1 No No Example 5-3 70 15.7 15.8 No No Comparative example 5-1 70 - - yes yes

It is apparent from Table 5 that in Examples 5-1 to 5-3 in which the exposed region 51C or the exposed region 52C and the separator 54 were adhered through the polymer electrolyte 53, no rupture of the packaging member 61 was observed at a high temperature; However, in Comparative Example 5-1 in which they were not adhered by the polymer electrolyte 53, rupture of the packaging member 61 was observed at high temperature. It is considered that the rupture of the packaging member 61 is caused by heat generation caused by a short circuit between the positive electrode 51 and the negative electrode 52 accompanied by thermal shrinkage of the separator 54 , thereby generating gas in the battery.

From these results, it was found that when at least one of the exposed region 51C and the exposed region 52C is adhered to the separator 54 through the polymer electrolyte 53, and the edge portion 54B of the separator 54 is adhered through the polymer electrolyte 53, even in a high-temperature environment, Thermal shrinkage of the separator 54 can be prevented, and as a result, heat generation caused by a short circuit between the positive electrode and the negative electrode can be prevented.

Although the present invention has been described with reference to the embodiments and examples, the present invention is not limited to these embodiments and examples, and various modifications can be made. For example, in the foregoing embodiments and examples, a battery using lithium as an electrode reactant was described, however, the present invention is applicable to a battery in which any other alkali metal such as sodium (Na) or potassium (K), alkaline earth metal such as magnesium Or in the case of calcium (Ca) or other light metals such as aluminum.

Also, in these embodiments and examples, the case of using an electrolytic solution as an electrolyte and the case of using a gel electrolyte in which a polymer holds an electrolytic solution as an electrolyte are described; however, an electrolytic solution or a gel electrolyte and any other mixture of electrolytes. Examples of other electrolytes include organic solid electrolytes formed by dissolving or dispersing electrolyte salts in polymers having ion conductivity, inorganic solid electrolytes including ion-conductive inorganic compounds such as ion-conductive ceramics, ion-conductive glass, or ion crystals.

Furthermore, in these embodiments and examples, the case where the cathode 21 and the anode 22 are spirally wound and the case where a plurality of cathodes 51 and a plurality of anodes 52 are laminated are described; however, the cathode and the anode are foldable. The present invention is applicable not only to secondary batteries but also to any other batteries such as primary batteries in a similar manner.

It should be understood by those skilled in the art that various modifications, combinations, recombinations and substitutions may be made depending on design requirements and other factors within the scope of the appended claims or the equivalents thereof.

Claims (7)

1. A battery, comprising: A positive electrode and a negative electrode in a film-like packaging member, the positive electrode and the negative electrode are opposed to each other through a polymer electrolyte in between and a separator, the polymer electrolyte comprising a polymer, wherein the active material layer is disposed on a current collector in at least one of the positive and negative electrodes, and With the polymer electrolyte in the middle, exposed regions on the current collector where the active material layer is not arranged and the separator are at least partially adhered to each other. 2. The battery according to claim 1, wherein The peel strength when the exposed region and the separator are peeled off from each other is 5 mN/mm or more. 3. The battery according to claim 1, wherein The polymer includes a polymer comprising vinylidene fluoride as a component. 4. The battery according to claim 1, wherein The polymer electrolyte has a thickness of 1 μm or more. 5. The battery according to claim 1, wherein the positive and negative electrodes are spirally wound with the separator to form a spirally wound body, and In the spirally wound body, the adhesion region between the current collector and the separator is located at the end on the center side and the end on the outside. 6. The battery according to claim 1, wherein With a separator in between, the positive and negative electrodes are alternately laminated to form a laminate, and The adhesion region between the current collector and the separator is located at a connection portion connected to a lead that guides the electromotive force generated in the laminate to the outside. 7. The battery according to claim 6, wherein The separator is larger than an area in which the active material layer of the positive electrode and the active material layer of the negative electrode are formed, and edge portions at the top and bottom are at least partially adhered to each other through the polymer electrolyte in the middle.

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