JP2012174438A - Packaging material for electrochemical cell and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a packaging material for an electrochemical cell, which prevents the occurrence of an internal short circuit while reducing a producing cost.SOLUTION: The packaging material for the electrochemical cell comprises at least: a substrate layer 111; a metal foil layer 112; and a thermally adhesive resin layer 113 which are sequentially stacked, and seals an electrochemical cell body 122 in an inner part of a housing part that is formed by making the thermally adhesive resin layers 113 face each other and heat-sealing circumferences of the layers. A heat-resistant film 140 which includes a heat-resistant resin layer 142 and has electrolyte resistance is provided at a part of an inner side of the thermally adhesive resin layer 113.

Description

  The present invention relates to a packaging material for an electrochemical cell that exhibits stable heat resistance while suppressing production cost, and a method for producing the same.

  FIG. 8 is a schematic cross-sectional view showing the layer structure of the packaging material for electrochemical cells. The packaging material 210 for an electrochemical cell includes a base material layer 211, a metal foil layer 212, and a heat-adhesive resin layer 213 that are sequentially laminated, and heat-sealing the peripheral portion with the heat-adhesive resin layers 213 facing each other. An exterior body of the electrochemical cell is formed.

  In a lithium ion battery including such an exterior body, the lithium ion battery itself may generate heat due to overcharging or the like, and a part of the heat-adhesive resin layer 213 may be melted. At this time, there has been a problem that a cell or a current collector housed in the exterior body and the metal foil layer 212 come into contact with each other to cause an internal short circuit.

  Patent Document 1 discloses an exterior body in which a heat-adhesive resin layer is composed of three layers of an acid-modified polyolefin layer, a high melting point polypropylene layer, and an ethylene / propylene random copolymer layer (thermoadhesive resin layer). Since the high melting point polypropylene layer is difficult to melt, an internal short circuit between the battery tab and the metal foil layer 212 is prevented. Patent Document 2 discloses a lithium ion battery having a current collector covered with an insulating resin. Even if a part of the heat-adhesive resin layer is melted, the insulating resin is not melted, and contact between the current collector and the metal foil layer is prevented.

JP 2007-273398 A JP 2009-181899 A

  However, according to the exterior body of Patent Document 1, the high melting point polypropylene layer is laminated by melt extrusion. The melt-extruded polypropylene resin generally has a melting point of around 140 ° C., and even a high-melting type is around 160 ° C. For this reason, the internal short circuit resulting from heat_generation | fever cannot fully be suppressed. Moreover, according to the exterior body of Patent Document 2, the process of covering the current collector with an insulating resin is complicated, and the manufacturing cost of the lithium ion battery increases.

  An object of this invention is to provide the packaging material for electrochemical cells which prevents generation | occurrence | production of an internal short circuit, and its manufacturing method, reducing manufacturing cost in view of the said problem.

  In order to achieve the above object, the present invention comprises at least a base material layer, a metal foil layer, and an innermost heat-adhesive resin layer laminated in sequence, and heats the periphery by facing the heat-adhesive resin layer. In a container formed by sealing, a positive electrode made of a positive electrode active material and a positive electrode current collector, a negative electrode made of a negative electrode active material and a negative electrode current collector, and an electrolyte filled between the positive electrode and the negative electrode, A packaging material for an electrochemical cell for sealing an electrochemical cell body including a heat-resistant film having an electrolytic solution resistance and including a heat-resistant resin layer on a part of the inside of the heat-adhesive resin layer. It is a feature.

  Further, in the packaging material for an electrochemical cell having the above-described configuration, the present invention provides a plurality of the positive electrode current collectors or the negative electrode current collectors, which are joined to the positive electrode tab or the negative electrode tab in an overlapping state, respectively. A packaging material for an electrochemical cell in which a tip is extended to the outside while sandwiching the electrode, wherein the heat-resistant film is provided in a region facing the positive electrode current collector and the negative electrode final current collector.

  Further, the present invention provides the electrochemical cell packaging material having the above-described structure, wherein the electrochemical cell packaging material is embossed, and the heat resistance is applied to a region including a boundary portion between a side wall and a bottom surface formed by embossing. A film is provided.

  Moreover, the present invention provides the electrochemical cell packaging material having the above-described configuration, wherein the heat-resistant film includes an acid-modified polyolefin layer on one surface of the heat-resistant resin layer, and the acid-modified polyolefin layer and the heat-adhesive resin layer include It is characterized by joining.

  In the electrochemical cell packaging material having the above-described structure, the present invention is characterized in that the heat-resistant resin layer has a melting point of 200 ° C. or higher.

  The electrochemical cell of the present invention is characterized by using the electrochemical cell packaging material having the above-described configuration.

  In addition, the method for producing a packaging material for an electrochemical cell according to the present invention includes a heat-resistant resin in a part of the packaging material for an electrochemical cell in which at least a base material layer, a metal foil layer, and an innermost thermal adhesive resin layer are sequentially laminated. A temporary attachment step of temporarily attaching a heat-resistant film having an acid-modified polyolefin layer having adhesiveness on one surface of the layer and having an electrolytic solution resistance; and a post-step of the temporary attachment step, for the electrochemical cell And a heat fusion step of heat-sealing the heat-adhesive resin layer and the acid-modified polyolefin layer having adhesiveness by heating the packaging material for a predetermined time in an environment of a predetermined temperature.

  The method for producing an electrochemical cell packaging material of the present invention is a pre-process of the temporary attachment step, and includes a molding step of embossing the electrochemical cell packaging material to form a side wall. Yes.

  According to the first configuration of the present invention, even when the electrochemical cell main body generates heat and a part of the heat-adhesive resin layer is melted, the electrochemical cell main body and the electrochemical cell main body are interposed through the heat-resistant film including the heat-resistant resin layer. The metal foil layer does not contact. Thereby, generation | occurrence | production of an internal short circuit can be prevented.

  According to the second configuration of the present invention, even when the positive electrode current collector or the negative electrode current collector generates heat, the positive electrode current collector is interposed via the heat resistant film provided in the region facing the positive electrode current collector and the negative electrode current collector. It can prevent that an electrical power collector or a negative electrode electrical power collector and a metal foil layer contact.

  According to the 3rd structure of this invention, a side wall and a bottom face are formed by embossing the packaging material for electrochemical cells, and an electrochemical cell main body can be accommodated in the space formed by a side wall and a bottom face. At this time, by providing the heat resistant film in the region including the boundary portion between the side wall and the bottom surface, the region adjacent to the positive electrode current collector and the negative electrode current collector is protected by the heat resistant film. Therefore, it can prevent that a positive electrode collector or a negative electrode collector, and a metal foil layer contact via a heat resistant film.

  According to the fourth configuration of the present invention, the heat-resistant film includes the acid-modified polyolefin layer on one surface of the heat-resistant resin layer, so that the heat-adhesive resin layer and the acid-modified polyolefin layer are melt-bonded and heated. A heat-resistant film can be easily provided inside the adhesive resin layer.

  According to the fifth configuration of the present invention, since the melting point of the heat-resistant resin layer is 200 ° C. or higher, the heat-resistant film is not easily melted even if the electrochemical cell body generates heat. Thereby, it can prevent stably that an electrochemical cell main body and a metal foil layer contact.

  According to the 6th structure of this invention, the electrochemical cell which prevents generation | occurrence | production of an internal short circuit can be provided by using the packaging material for electrochemical cells.

  According to the seventh configuration of the present invention, the heat-resistant film is temporarily attached to a part of the packaging material for an electrochemical cell in which at least the base material layer, the metal foil layer, and the innermost heat-adhesive resin layer are sequentially laminated. This facilitates positioning when bonding the heat resistant film.

  According to the 8th structure of this invention, before the temporary attachment process of temporarily attaching a heat resistant film, the packaging material for electrochemical cells is emboss-molded and a recessed part is formed, and it adheres to the internal shape of a recessed part. And heat-resistant film can be adhered.

Schematic sectional view showing the layer structure of the packaging material for electrochemical cells of the present invention The perspective view of the lithium ion battery which used the packaging material for electrochemical cells of this invention for the exterior body A-A 'line sectional view of the lithium ion battery in FIG. The perspective view of the lithium ion battery main body which the packaging material for electrochemical cells of this invention accommodates Sectional drawing of the lithium ion battery main body which the packaging material for electrochemical cells of this invention accommodates Sectional drawing which shows the modification of the exterior body which concerns on the packaging material for electrochemical cells of this invention The exploded sectional view showing the modification of the lithium ion battery which used the packaging material for electrochemical cells of the present invention for the exterior body Schematic sectional view showing the layer structure of a conventional packaging material for electrochemical cells

  Hereinafter, the packaging material for an electrochemical cell of the present invention will be described with reference to the drawings. FIG. 1 is a schematic sectional view showing the layer structure of the packaging material for electrochemical cells of the present invention, FIG. 2 is a perspective view of a lithium ion battery using the packaging material for electrochemical cells of the present invention, and FIG. It is the sectional view on the AA 'line of the lithium ion battery in FIG.

  The electrochemical cell packaging material 110, which is a multilayer film, is formed by sequentially laminating a base material layer 111, a metal foil layer 112, an acid-modified polyolefin layer 115, and a heat-adhesive resin layer 113. A heat resistant film 140 is provided in part. The heat resistant film 140 is configured by laminating an acid-modified polyolefin layer 141 on a heat resistant resin layer 142. Although not shown, the surface of the heat resistant resin layer 142 is subjected to an anchor coat process. In addition, a chemical conversion treatment layer is applied to both surfaces of the metal foil layer 112 to increase the interlayer adhesion strength between the metal foil layer 112, the acid-modified polyolefin layer 115, and the adhesive layer 114. An adhesive layer 114 is provided between the metal foil layer 112 and the base material layer 111.

  In addition, the packaging material 110 for electrochemical cells according to the present invention may include the above-described layers and may have different layers interposed between the layers. Specific examples of the respective layers constituting the electrochemical cell packaging material 110 will be described later in detail.

  The lithium ion battery 121 is configured by sealingly housing a lithium ion battery main body 122 inside an exterior body 120 made of the electrochemical cell packaging material 110. The exterior body 120 includes a concave portion 120a having a storage portion and a sheet portion 120b covering the storage portion. The recess 120a is produced by press-molding a rectangular electrochemical cell packaging material 110. The recess 120a includes a bottom surface 120c, a side wall 120d that rises upward from the outer periphery of the bottom surface 120c, and a peripheral surface 120e that extends outward from the upper edge of the side wall 120d in the horizontal direction.

  The vicinity of the boundary 120f between the side wall 120d and the bottom surface 120c is a position closest to the lithium ion battery main body 122 in a state where the lithium ion battery main body 122 is accommodated. The heat resistant film 140 is provided in a region including at least the boundary portion 120f. Further, a region extending from the slope of the side wall 120d to a part of the bottom surface 120c is a region adjacent to the current collectors 125a and 125b that are densely packed. For this reason, the heat resistant film 140 is provided across the slope of the side wall 120d and part of the bottom surface 120c. Moreover, the heat resistant film 140 is provided also in a part of the sheet portion 120b.

  The lithium ion battery main body 122 is stored in a storage space surrounded by the bottom surface 120c and the side wall 120d of the recess 120a. The positive electrode tab 123a and the negative electrode tab 123 connected to the lithium ion battery main body 122 extend to the outside while being sandwiched by the concave portion 120a and the sheet portion 120b with the tab film 130 interposed on the peripheral surface 120e. The positive electrode tab 123a and the negative electrode tab 123b are partially bent along the horizontal surface of the peripheral surface 120e from the slope of the side wall 120d.

  FIG. 4 is a perspective view of a lithium ion battery main body accommodated in the electrochemical cell packaging material of the present invention, and FIG. 5 is a cross-sectional view of the lithium ion battery main body accommodated in the electrochemical cell packaging material of the present invention. The lithium ion battery main body 122 includes a positive electrode composed of a positive electrode active material and a positive electrode current collector 125a, a negative electrode composed of a negative electrode active material and a negative electrode current collector 125b, and an electrolyte (not shown) filled between the positive electrode and the negative electrode. Cell (power storage unit) 126 including The cell 126 is formed by laminating a plurality of positive electrode plates from which the positive electrode current collector 125a extends and negative electrode plates from which the negative electrode current collector 125b extends. A plurality of positive plates and negative plates are alternately stacked via separators (not shown). The plurality of stacked positive electrode current collectors 125a and negative electrode current collectors 125b are overlapped and connected to one positive electrode tab 123a and one negative electrode tab 123b, respectively.

  When the lithium ion battery main body 122 is stored in the storage space of the recess 120a, the positive electrode current collector 125a, the negative electrode current collector 125b, and the heat resistant film 140 are opposed to each other and close to each other. Thereby, even when a part of the heat-adhesive resin layer 113 is melted, the heat-resistant film 140 prevents the positive electrode current collector 125a or the negative electrode current collector 125b from contacting the metal foil layer 112. Therefore, occurrence of an internal short circuit of the lithium ion battery 121 can be prevented.

  FIG. 6 is a cross-sectional view showing a modification of the outer package according to the packaging material for electrochemical cells of the present invention. Also in the pouch-type outer package 120, the positive electrode current collector 125a or the negative electrode current collector 125b and the metal foil layer are provided by disposing the heat resistant film 140 in a region facing the positive electrode current collector 125a and the negative electrode current collector 125b. Contact with 112 can be prevented.

  FIG. 7 is an exploded cross-sectional view showing a modified example of a lithium ion battery using the packaging material for an electrochemical cell of the present invention as an outer package. The heat resistant film 140 may be provided in a region facing the other part of the lithium ion battery main body 122. For example, by providing the heat resistant film 140 so as to cover the entire bottom surface 120c, the cell 126 and the metal foil layer 112 can be prevented from contacting each other.

  Next, the manufacturing method of the packaging material for electrochemical cells is demonstrated. In the molding process, a laminated film in which the base material layer 112, the metal foil layer 112, and the innermost heat-adhesive resin layer 113 are sequentially laminated is cut into a rectangular shape, and then pressed to form a recess 120a having a storage portion. To do. The storage part of the recess 120a is constituted by a bottom surface 120c and a side wall 120d.

  In the temporary attachment step, the heat resistant film 140 including the weakly adhesive acid-modified polyolefin layer 141 is temporarily attached to a predetermined region including the boundary portion 120f between the bottom surface 120c and the side wall 120d. The acid-modified polyolefin layer 141 is added with a tackifier resin and has adhesiveness or pressure sensitivity.

  In the heat sealing step, the laminated film temporarily attached with the heat resistant film 140 is heated for a predetermined time in an environment at a predetermined temperature. As a result, the low-melting point acid-modified polyolefin layer 141 is thermally fused to the heat-adhesive resin layer 113 to complete the electrochemical cell packaging material 110. The acid-modified polyolefin layer 141 is made of a resin having a melting point lower than that of the heat-adhesive resin layer 113, so that the acid-modified polyolefin layer 141 is heated to the heat-adhesive resin layer 113 without modifying the heat-adhesive resin layer 113. Can be fused.

  By providing the temporary attachment step before the heat fusion step, positioning when the heat resistant film 140 is bonded can be easily performed. Further, by providing a molding step before the temporary attachment step, it is possible to prevent the heat resistant film 140a from being peeled off from the thermal adhesive resin layer 113 during press molding. Thereby, the heat resistant film 140 can be adhered to the inner shape of the recess 120a.

  Next, each layer which comprises the packaging material 110 for electrochemical cells is demonstrated in detail. Stretched polyester or stretched nylon film can be used for the base material layer 111, and examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, copolymerized polyester, and polycarbonate. Examples of nylon include polyamide resin, that is, nylon 6, nylon 6,6, a copolymer of nylon 6 and nylon 6,6, nylon 6,10, polymetaxylylene adipamide (MXD6), and the like.

  In addition, the base material layer 111 can be laminated with films of different materials in addition to a polyester film or a nylon film in order to improve pinhole resistance and insulation when used as a battery outer package.

  The metal foil layer 112 is a layer for preventing water vapor from entering the inside of the lithium ion battery 121 from the outside, and stabilizes pinholes and processability (pouching, embossing formability) of the metal foil layer alone. In order to have pinhole resistance, aluminum having a thickness of 15 μm or more is used.

  In addition, when the generation of pinholes is improved and the type of the outer package of the lithium ion battery is an embossed type, the material of aluminum used as the metal foil layer 112 is selected in order to prevent the occurrence of cracks in the embossing molding. It is desirable that the iron content is 0.3 to 9.0% by weight, preferably 0.7 to 2.0% by weight.

  As a result, compared to aluminum that does not contain iron, aluminum has better spreadability, less pinholes are generated by bending as an exterior body, and side walls can be easily formed when embossing packaging material. Can do. In addition, when the iron content is less than 0.3% by weight, effects such as prevention of pinholes and improvement of embossing formability are not observed, and the iron content of aluminum exceeds 9.0% by weight. In this case, the flexibility as aluminum is hindered, and the bag-making property as a packaging material is deteriorated.

  In addition, aluminum produced by cold rolling changes its flexibility, waist strength and hardness under annealing (so-called annealing treatment) conditions, but the aluminum used in the present invention is harder than the non-annealed hard-treated product. Aluminum which tends to be soft with some or complete annealing is preferred.

  In addition, the chemical conversion treatment is performed by chromium-based chemical conversion treatment such as chromate chromate treatment, phosphoric acid chromate treatment, and coating-type chromate treatment, or non-chromium (coating-type) chemical conversion treatment such as zirconium, titanium, and zinc phosphate. Although it is formed on the surface of the foil layer 112, a coating-type chemical conversion treatment, particularly an aminated phenol polymer, in that a continuous treatment is possible and a water washing step is unnecessary and the treatment cost can be reduced. Most preferably, the treatment is performed with a treatment solution containing a trivalent chromium compound and a phosphorus compound.

  In addition, the chemical conversion treatment may be formed by selecting a known coating method such as a bar coating method, a roll coating method, a gravure coating method, or a dipping method for the treatment liquid. In addition, before the chemical conversion treatment, the surface of the metal foil layer 112 is preferably subjected to chemical treatment using a known degreasing treatment method such as an alkali dipping method, an electrolytic cleaning method, an acid cleaning method, or an acid activation method. It is preferable from the viewpoint that the function of the treatment can be maximized and can be maintained for a long time.

  The resin type of the heat-adhesive resin layer 113 differs depending on whether or not the tab film 130 is interposed between the heat-adhesive resin layer 113 and the positive electrode tab 123a or the negative electrode tab 123b. When the tab film 130 is interposed, a film made of a propylene-based resin alone or a mixture may be used. When the tab film 130 is not interposed, a film made of an acid-modified olefin resin graft-modified with an unsaturated carboxylic acid is used. Use it.

  Polypropylene is preferably used as the heat-adhesive resin layer 113, but a single layer or multilayer of linear low density polyethylene or medium density polyethylene, or a single resin composed of a blend resin of linear low density polyethylene and medium density polyethylene. It can also be used as a film composed of layers or multilayers.

  For each type of polypropylene, that is, random propylene, homopropylene, block propylene, and linear low density polyethylene, medium density polyethylene, low crystalline ethylene-butene copolymer, low crystalline propylene-butene copolymer, A terpolymer composed of a three-component copolymer of ethylene, butene, and propylene, silica, zeolite, an antiblocking agent (AB agent) such as acrylic resin beads, a fatty acid amide slip agent, and the like may be added.

  The acid-modified polyolefin layer 115 is preferably made of acid-modified polypropylene in order to stably bond the metal foil layer 112 and the heat-adhesive resin layer 113. The acid-modified polyolefin layers 115 and 141 need to be appropriately selected depending on the resin type used for the heat-adhesive resin layer 113, and when an acid-modified polyolefin resin other than acid-modified polypropylene is used, a polyolefin graft-modified with an unsaturated carboxylic acid. Resins, copolymers of ethylene or propylene and acrylic acid or methacrylic acid, or metal-crosslinked polyolefin resins, butene component, ethylene-propylene-butene copolymer, amorphous ethylene as required -You may add 5% or more of propylene copolymers, a propylene-alpha-olefin copolymer, etc.

When using acid-modified polypropylene,
(1) A homotype having a bigat softening point of 115 ° C or higher and a melting point of 150 ° C or higher,
(2) A copolymer of ethylene-propylene having a bigat softening point of 105 ° C or higher and a melting point of 130 ° C or higher (random copolymer type)
(3) A simple substance or a blended product obtained by acid-modified polymerization using an unsaturated carboxylic acid having a melting point of 110 ° C. or higher can be used.

  The acid-modified polyolefin layer 141 can contain a tackifying resin to impart tackiness or pressure sensitivity. Thereby, the acid-modified polyolefin layer 141 can be temporarily attached to the heat resistant resin layer 113. Examples of the tackifier resin used include rosins (polymerized rosin, hydrogenated rosin, rosin ester, etc.), terpene resins, terpene phenol resins, coumarone indene resins, petroleum resins, and the like.

  As the heat resistant resin layer 142, a biaxially stretched polyethylene naphthalate film (hereinafter referred to as PEN) or a biaxially stretched polyethylene terephthalate film (hereinafter referred to as PET) can be used. PEN and PET have a higher melting point and glass transition point than the general polyolefin resin forming the heat-adhesive resin layer 113. For this reason, even when a part of the heat-adhesive resin layer 113 is melted, the heat-resistant resin layer 142 remains without being melted. Therefore, it is possible to prevent the metal foil layer 112 and the heated lithium ion battery main body 122 from coming into contact with each other and causing an internal short circuit. In addition, you may give well-known easy-adhesion means, such as an anchor coat process, a corona treatment, an ozone treatment, a plasma treatment, as needed on the surface of PEN or PEN.

  Examples of heat-resistant resins other than PEN and PET include unstretched or stretched films such as polyamide, polyphenylene sulfide (PPS), polymethylpentene (TPX (registered trademark)), polyacetal (POM), cyclic polyolefin, and polyethylene (PP). Can be used.

  The adhesive layer 114 firmly bonds the base material layer 111 and the metal foil layer 112, the heat resistant resin layer 142 and the acid-modified polyolefin layer 141. Such interlayer adhesion can be performed by a dry lamination method, an extrusion lamination method, a coextrusion lamination method, a thermal lamination method, or the like.

  When laminating by the dry laminating method, polyester, polyethyleneimine, polyether, cyanoacrylate, urethane, organic titanium, polyetherurethane, epoxy, polyesterurethane, imide, isocyanate Various adhesives based on polyolefin, polyolefin, and silicone can be used.

  The present invention is not limited to the above-described embodiments, and various modifications are possible. Embodiments obtained by appropriately combining technical means disclosed in different embodiments are also included in the present invention. Included in the technical scope.

  Electrochemical cells include nickel metal hydride batteries, nickel cadmium batteries, lithium metal primary batteries or secondary batteries, lithium polymer batteries, and other chemical batteries, electric double layer capacitors, capacitors, and electrolytic capacitors in addition to lithium ion batteries. The chemical cell body is a cell including a positive electrode composed of a positive electrode active material and a positive electrode current collector before enclosing packaging material, a negative electrode composed of a negative electrode active material and a negative electrode current collector, and an electrolyte filled between the positive electrode and the negative electrode ( It includes all electrical device elements that generate electrical energy, such as a power storage unit and electrode terminals connected to the positive electrode and the negative electrode in the cell. The present invention relates to a packaging material for packaging these electrochemical cells.

  Hereinafter, the operation and effect of the present invention will be specifically described with reference to examples. Example 1 evaluates the insulating property of the packaging material for an electrochemical cell to which a heat resistant film is adhered.

  A chemical conversion treatment was performed on both surfaces of aluminum (thickness 40 μm), and a stretched nylon film (thickness 25 μm) was bonded to one chemical conversion treatment surface by a dry laminating method via a two-component curable polyurethane adhesive. Next, a two-layer coextruded film of an acid-modified polypropylene film (thickness 23 μm, hereinafter abbreviated as acid-modified PP) and a polypropylene film (thickness 23 μm, hereinafter abbreviated as PP film) was laminated on the other chemical conversion treatment surface. Thereby, a laminated film composed of stretched nylon film / aluminum / acid-modified PP / PP film was obtained.

In addition, the chemical conversion treatment layer was applied with a treatment liquid composed of a phenol resin, a chromium fluoride compound, and phosphoric acid by a roll coating method, and baked under a condition that the film temperature was 180 ° C. or higher. Here, the coating amount of chromium was 10 mg / m ² (dry weight).

  Next, heat resistance composed of PEN / acid-modified PP is obtained by melt-extruding an acid-modified polypropylene film (28 μm) having weak adhesion on one side of an anchor coat-treated polyethylene naphthalate film (thickness: 12 μm). A film was obtained.

  The laminated film was cut to 55 mm × 32 mm and then embossed to a depth of 5.5 mm using a straight mold. A heat resistant film was temporarily attached in the vicinity of the boundary between the side wall and the bottom formed by embossing. Next, it heated for 2 minutes in 80 degreeC environment.

  The battery element was stored in the laminated film to which the heat-resistant film was bonded so that the tabs protruded to the outside, and the new laminated film was covered. Finally, the peripheral edge portion was heat sealed (sealing temperature 190 ° C., surface pressure 1 MPa, sealing time 3.0 seconds, sealing width 7 mm), and the battery element was hermetically housed inside.

  When overcharging was repeatedly performed on the battery produced by the above process, no short circuit occurred. From the above, it was found that the packaging material for an electrochemical cell to which a heat resistant film was adhered had a certain insulating property.

  INDUSTRIAL APPLICABILITY The present invention can be used as an outer package for packaging chemical batteries such as nickel metal hydride batteries, nickel cadmium batteries, lithium metal primary batteries or secondary batteries, lithium polymer batteries, and electric double layer capacitors, capacitors, and electrolytic capacitors.

DESCRIPTION OF SYMBOLS 110 Electrochemical cell packaging material 111 Base material layer 112 Metal foil layer 113 Thermal adhesive resin layer 114 Adhesive layer 115 Acid-modified polyolefin layer 120 Exterior body 120a Recess 120b Sheet part 120c Bottom face 120d Side wall 120e Peripheral face 120f Boundary part 121 Lithium ion Battery 122 Lithium ion battery main body 123a Positive electrode tab 123b Negative electrode tab 125a Positive electrode current collector 125b Negative electrode current collector 126 Cell 130 Tab film 140 Heat resistant film 141 Acid-modified polyolefin layer 142 Heat resistant resin layer

Claims (8)

At least a base material layer, a metal foil layer, and an innermost thermal adhesive resin layer are sequentially laminated,
Inside the housing part formed by heat sealing the periphery with the thermal adhesive resin layer facing each other, a positive electrode made of a positive electrode active material and a positive electrode current collector, a negative electrode made of a negative electrode active material and a negative electrode current collector, An electrolyte filled between the positive electrode and the negative electrode, and an electrochemical cell packaging material for sealing an electrochemical cell body,
A packaging material for electrochemical cells, wherein a heat-resistant film having a heat-resistant resin layer and having an electrolytic solution resistance is provided on a part of the inside of the heat-adhesive resin layer. A packaging for an electrochemical cell in which a plurality of the positive electrode current collectors or the negative electrode current collectors are overlapped and joined to the positive electrode tab or the negative electrode tab, respectively, and the tip is extended to the outside while sandwiching the positive electrode tab and the negative electrode tab Material,
The packaging material for an electrochemical cell according to claim 1, wherein the heat-resistant film is provided in a region facing the positive electrode current collector and the negative electrode final collector. The packaging material for the electrochemical cell is embossed,
The packaging material for an electrochemical cell according to claim 2, wherein the heat-resistant film is provided in a region including a boundary portion between a side wall and a bottom surface formed by emboss molding.   The heat-resistant film includes an acid-modified polyolefin layer on one surface of the heat-resistant resin layer, and the acid-modified polyolefin layer and the heat-adhesive resin layer are bonded to each other. The packaging material for electrochemical cells according to claim 1.   The packaging material for an electrochemical cell according to claim 4, wherein the heat-resistant resin layer has a melting point of 200 ° C or higher.   An electrochemical cell using the electrochemical cell packaging material according to any one of claims 1 to 5. An acid-modified polyolefin layer having adhesiveness on one surface of the heat-resistant resin layer is formed on a part of the packaging material for an electrochemical cell in which at least a base material layer, a metal foil layer, and an innermost heat-adhesive resin layer are sequentially laminated. A temporary attachment step of temporarily attaching a heat-resistant film having an electrolytic solution resistance;
It is a post-process of the temporary attachment step, and heat-melts the thermoadhesive resin layer and the acid-modified polyolefin layer having adhesiveness by heating the packaging material for electrochemical cells for a predetermined time in an environment of a predetermined temperature. A method for producing a packaging material for an electrochemical cell, comprising: a heat-sealing step of attaching the material.   10. The manufacturing method for a packaging material for an electrochemical cell according to claim 9, comprising a molding step for forming a side wall by embossing the packaging material for an electrochemical cell, which is a pre-process of the temporary attachment step. Method.

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