JP5278521B2 - Packaging materials for electrochemical cells - Google Patents

Description

  The present invention relates to a packaging material for an electrochemical cell that forms a packaging body for an electrochemical cell.

  A conventional packaging material for electrochemical cells is disclosed in Patent Document 1. This packaging material is a laminate in which a base material layer, a barrier layer, and an innermost thermal adhesive layer are sequentially laminated. The thermal adhesive layer of the electrochemical cell is heat-sealed with the thermal adhesive layers facing each other. A package is formed. The packaging body is provided with a space for accommodating the electrochemical cell body such as an electrolyte and a separator, and the electrode tab connected to the electrochemical cell body extends to the outside while being sandwiched by the packaging body at the thermal bonding portion. .

  In addition, a chemical conversion treatment layer is applied to at least the surface of the metal foil constituting the barrier layer on the side of the thermal adhesive layer, thereby imparting corrosion resistance to the electrolytic solution to the metal foil and increasing the laminate strength. The chemical conversion treatment layer is formed by applying a treatment liquid containing an aminated phenol polymer, a trivalent chromium compound and phosphoric acid to the surface of the metal foil.

JP 2007-273398 A

  However, according to the packaging material described above, if there is a burr on the edge of the electrode tab, or if carbon in the electrode active material or fine metallic foreign matter adheres to the surface of the thermal adhesive layer on the inner surface of the packaging material, heat sealing Due to the heat and pressure of the heat, the thermal adhesive layer melts, and burrs, carbon, or minute metal foreign matter bite into the thermal adhesive layer, causing a short circuit between the electrode tab and the barrier layer.

  An object of this invention is to provide the packaging material for electrochemical cells which prevents generation | occurrence | production of a short circuit in view of the said problem.

  In order to achieve the above object, the present invention provides a base layer composed of at least a resin film, a thermal adhesive layer composed of a thermoadhesive resin disposed in the innermost layer, and between the base layer and the thermal adhesive layer. And a barrier layer made of a metal foil, the packaging material for an electrochemical cell, wherein at least the surface of the barrier layer on the side of the thermal adhesive layer has alumina particles and a modified epoxy resin. The chemical conversion treatment layer containing is formed.

  According to this configuration, the alumina particles and the modified epoxy resin contained in the chemical conversion treatment layer have insulating properties, and are not easily melted or crushed by heat and pressure during heat sealing. Therefore, even when burrs, carbon, or minute metal foreign matter bites into the thermal adhesive layer during heat sealing, the burrs, carbon, or minute metal foreign matter are blocked by the chemical conversion treatment layer and do not reach the metal foil of the barrier layer. Thereby, it is possible to prevent a short circuit from occurring between the electrode tab and the barrier layer. In addition, the chemical conversion treatment layer improves the surface adhesion (wetting property) of the barrier layer and provides corrosion resistance to the electrolytic solution.

  Further, the present invention is characterized in that, in the packaging material for an electrochemical cell having the above-described configuration, an insulating layer containing a modified epoxy resin is laminated on the chemical conversion treatment layer formed on the thermal adhesive layer side. According to this structure, the insulation as a packaging material for electrochemical cells is further improved by laminating the insulating layer on the chemical conversion treatment layer.

  Moreover, the present invention is characterized in that, in the electrochemical cell packaging material having the above-described configuration, the insulating layer has a thickness of 0.5 μm or more and 5 μm or less. According to this configuration, the laminate strength between the barrier layer and the heat bonding layer can be stably maintained while ensuring sufficient insulation.

  Moreover, the present invention is characterized in that, in the electrochemical cell packaging material having the above structure, the thickness of the insulating layer is larger than the particle diameter of the alumina particles.

  According to the present invention, the alumina particles and the modified epoxy resin contained in the chemical conversion treatment layer have insulating properties, and are not easily melted or crushed by heat and pressure during heat sealing. Therefore, even when burrs, carbon, or minute metal foreign matter bites into the thermal adhesive layer during heat sealing, the burrs, carbon, or minute metal foreign matter are blocked by the chemical conversion treatment layer and do not reach the metal foil of the barrier layer. As a result, even when heat sealing is performed with an electrode tab having burrs, or when heat sealing is performed with an electrode active material or a minute foreign metal bite, the metal foil of the barrier layer is protected by the chemical conversion treatment layer. It is possible to prevent a short circuit from occurring with the barrier layer.

The perspective view of the lithium ion battery which concerns on 1st Embodiment of this invention. AA line sectional view in FIG. Schematic sectional view showing the layer structure of the packaging material according to the first embodiment of the present invention Schematic sectional view showing the layer structure of the packaging material according to the second embodiment of the present invention

[First Embodiment]
Hereinafter, the packaging material 110 for an electrochemical cell according to the first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a lithium ion battery 121 according to the first embodiment, and FIG. 2 is a cross-sectional view taken along line AA in FIG.

  The lithium ion battery 121 is configured by housing a lithium ion battery main body 122 containing an electrolytic solution in the package 120. The package 120 includes a storage portion 120a that stores the lithium ion battery main body 122 and a sheet portion 120b that covers the storage portion 120a.

  The package 120 has a thermal bonding portion 120c at the periphery where the storage portion 120a and the sheet portion 120b overlap, and the inside is sealed. At this time, the positive electrode tab 123a and the negative electrode tab 123b connected to the lithium ion battery main body 122 extend outside while being sandwiched by the storage portion 120a and the sheet portion 120b with a tab film (not shown) interposed in the thermal bonding portion 120. ing.

  The lithium ion battery main body 122 is configured by a cell including 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. The The cell is formed by laminating a plurality of positive electrode plates from which a positive electrode current collector extends and negative electrode plates from which a negative electrode current collector extends. A plurality of positive plates and negative plates are alternately stacked via separators. The plurality of stacked positive electrode current collectors and negative electrode current collectors are overlapped and connected to a single positive electrode tab 123a and negative electrode tab 123b, respectively.

  FIG. 3 is a schematic cross-sectional view showing the layer structure of the packaging material 110 that forms the storage portion 120a and the sheet portion 120b. The packaging material 110 is formed by sequentially laminating a base material layer 112, a barrier layer 114, and a thermal bonding layer 116. Composed. The base material layer 112 and the barrier layer 114 are bonded via an adhesive layer 113, and the barrier layer 114 and the thermal adhesive layer 116 are bonded via an acid-modified polyolefin layer 115. Chemical conversion treatment layers 114 a are provided on both surfaces of the barrier layer 114, and the laminate strength of the barrier layer 114 and the acid-modified polyolefin layer 115, and the barrier layer 114 and the adhesive layer 113 is increased.

  As shown in FIG. 2, the storage portion 120a is manufactured by press-molding a packaging material 110 cut into a rectangular shape. In the molding process, the packaging material 110 is placed toward the concave female mold, and then cold-molded to a predetermined molding depth from the thermal adhesive layer 116 side with a male mold. The storage unit 120 and the sheet unit 120b are thermally bonded at the opposing thermal bonding layer 116.

  The base material layer 112 is made of a resin film and imparts high puncture resistance (pinhole resistance), insulation, workability, and the like to the package 120. Moreover, it is necessary to have the extensibility which can endure the press at the time of embossing.

  As the base material layer 112, a resin film such as a stretched polyester resin or a stretched nylon resin can be arbitrarily selected and used. Examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, copolymerized polyester, and polycarbonate. Examples of the nylon resin 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. .

  The barrier layer 114 is made of a metal foil, and a chemical conversion treatment layer 114a is formed on both surfaces. The barrier layer 114 prevents water vapor from entering the lithium ion battery 121 from the outside. In addition, aluminum having a thickness of 15 μm or more is used in order to stabilize pinholes of the barrier layer 114 and processability (pouching, embossing formability) and to have pinhole resistance.

  When the package 120 is an embossed type, the material of aluminum used as the barrier layer 114 is such that the iron content is 0.3 to 9.0% by weight, preferably 0.7 to 2.0% by weight. desirable.

  Thereby, compared with the aluminum which does not contain iron, the extensibility of aluminum is good, and the generation | occurrence | production of the pinhole by bending as the packaging body 120 decreases. In addition, the side wall can be easily formed when the packaging material 110 is embossed. In addition, when the iron content of aluminum is less than 0.3% by weight, effects such as prevention of generation of pinholes and improvement of embossing formability are not recognized. Moreover, when the iron content of aluminum exceeds 9.0% by weight, the flexibility as aluminum is hindered, and the bag-making property as a packaging material is deteriorated.

  Moreover, the flexibility, the strength of the waist, and the hardness of aluminum manufactured by cold rolling of the barrier layer 114 change under annealing (so-called annealing treatment) conditions. The aluminum of the barrier layer 114 is preferably aluminum that has been annealed and tends to be softer than a hard-treated product that has not been annealed.

  The chemical conversion treatment layer 114a is formed with a predetermined thickness by applying a treatment liquid containing alumina and a modified epoxy resin. At this time, the alumina particles and the modified epoxy resin contained in the chemical conversion layer 114a have insulating properties, and are not easily melted or crushed by heat and pressure during heat sealing. As a result, even when burrs, carbon, or minute metal foreign matter bites into the thermal adhesive layer 116 during heat sealing, the burrs, carbon, or minute metal foreign matter are blocked by the chemical conversion treatment layer 114a and the metal foil of the barrier layer 116 Not reach. Therefore, it is possible to prevent a short circuit from occurring between the positive electrode tab 123a, the negative electrode tab 123b, and the barrier layer 114.

  Moreover, the chemical conversion treatment layer 114a can improve the adhesiveness (wetting property) of the aluminum surface. Moreover, the chemical conversion treatment layer 114a imparts corrosion resistance to the aluminum surface. Thereby, it is possible to prevent the aluminum surface from being dissolved and corroded by hydrogen fluoride generated by the reaction between the electrolytic solution and moisture. In particular, it is possible to prevent aluminum oxide existing on the surface of aluminum from being dissolved and corroded. Therefore, delamination between the barrier layer 114 and the thermal bonding layer 116 and delamination between the barrier layer 114 and the base material layer 112 can be prevented.

  The chemical conversion treatment layer 114a is formed in a film form by applying a treatment liquid containing alumina particles and a modified epoxy resin to the aluminum surface and then baking it. As a forming method for the chemical conversion treatment, a known coating method such as a bar coating method, a roll coating method, a gravure coating method, or a dipping method may be selected and molded from the processing solution. By performing the coating type chemical conversion treatment, continuous treatment is possible and a water washing step is unnecessary, and the processing cost can be reduced.

  Further, it is desirable that the surface of the barrier layer 114 is preliminarily treated by a known degreasing method such as an alkali dipping method, an electrolytic cleaning method, an acid cleaning method, and an acid activation method before the chemical conversion treatment. Thereby, the function of chemical conversion treatment can be expressed to the maximum and maintained for a long time.

  Moreover, although the modified | denatured epoxy resin turns into a binder solution of an alumina particle for the process liquid of a chemical conversion treatment, you may mix phosphoric acid with a binder solution. The same effect can be obtained by using a mixed solution in which the modified epoxy resin and the aminated phenol polymer are mixed in a 1: 1 ratio instead of the modified epoxy resin alone.

  The alumina particles can enhance the insulation of the chemical conversion treatment layer 114a, and nano-sized particles are preferably used as the alumina particles. The alumina particles are preferably particles having an average particle diameter of 0.03 μm to 3.0 μm, and more preferably particles of 0.10 μm to 1.0 μm. When the average particle size exceeds 3.0 μm, the alumina particles are not uniformly dispersed, and the chemical conversion treatment layer 114a may be formed unevenly. When the average particle size is smaller than 0.03 μm, it is necessary to increase the amount of alumina particles added to the binder solution, and the laminate between the barrier layer 114 and the acid-modified polyolefin layer 115 and between the barrier layer 114 and the adhesive layer 113 is required. This leads to a decrease in strength and an increase in manufacturing costs.

  In addition to the alumina particles, the insulating property can be imparted to the chemical conversion treatment layer 114a by using ceramic material or metal oxide particles. Examples of the ceramic material particles include first aluminum phosphate and aluminum nitride. Examples of the metal oxide material include zircon oxide and titanium oxide.

  As the modified epoxy resin used in the treatment liquid of the chemical conversion treatment layer 114a, a modified epoxy resin having bisphenol A or bisphenol F as a unit in the skeleton is used. Examples of the modified epoxy resin include a silane-modified product in which part or all of the glycidyl group of the epoxy resin is silane-modified, and a phosphoric acid-modified product in which part or all of the glycidyl group of the epoxy resin is modified with phosphoric acids. The chemical conversion treatment layer 114a formed using these modified epoxy resins is excellent in insulation.

  Examples of the epoxy resin having bisphenol A or bisphenol F as a unit in the skeleton include those obtained by repeated dehydrochlorination reaction and addition reaction of epichlorohydrin and bisphenol A or bisphenol F. Moreover, what is obtained by repeating the addition reaction between the epoxy compound which has 2 or more, preferably 2 glycidyl groups and bisphenol A or bisphenol F is also mentioned.

  Examples of the epoxy compound include sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, trimethylolpropylene polyglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and the like. Is mentioned.

  The silane-modified product of epoxy resin having bisphenol A or bisphenol F as a unit in the skeleton may be silane-modified using a silane coupling agent at the stage of synthesis. There is no restriction | limiting in particular about the kind of silane coupling agent at the time of carrying out silane modification | denaturation of an epoxy resin, and the modification amount. Further, by modifying the epoxy resin with silane, the adhesion between the barrier layer 114 and the thermal bonding layer 116 is increased, and the corrosion resistance of the barrier layer 114 to the electrolytic solution is improved.

  As the silane coupling agent, vinyltrichlorosilane, vinyltris (2-methoxyethoxy) silane, vinyltriethoxysilane, vinyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyl Trimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxy Silane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3- Le mercaptopropyl trimethoxysilane, 3-chloropropyl trimethoxy silane, and the like ureidopropyltriethoxysilane.

  Moreover, the phosphoric acid modification | denaturation of the epoxy resin which has bisphenol A or bisphenol F as a unit in frame | skeleton is performed by making an epoxy resin react with phosphoric acids or ester of phosphoric acids. As phosphoric acids, metaphosphoric acid, phosphonic acid, orthophosphoric acid, pyrophosphoric acid and the like can be used. Moreover, as ester of phosphoric acid, monoesters, such as metaphosphoric acid, phosphonic acid, orthophosphoric acid, and pyrophosphoric acid, can be used, for example, monomethyl phosphoric acid, monooctyl phosphoric acid, monophenyl phosphoric acid etc. are mentioned.

  Moreover, since the phosphoric acid modified substance of an epoxy resin produces | generates a more stable water-dispersible resin composition by neutralizing with an amine compound, it is preferable to neutralize. Examples of the amine compound include ammonia; alkanolamines such as dimethanolamine and triethanolamine; alkylamines such as diethylamine and triethylamine; alkylalkanolamines such as dimethylethanolamine.

  The degree of silane modification and phosphoric acid modification is not particularly limited as long as the effect of these modifications is recognized, but usually, the Si-OH equivalent or P-OH group equivalent is in the range of 150 to 1,000. It is preferable to be modified. Moreover, it is more preferable to modify | denature so that it may become the range of 300-800.

  The epoxy equivalent of the epoxy resin (the chemical formula amount of the epoxy resin per epoxy group, in other words, the value obtained by dividing the molecular weight of the epoxy resin by the number of epoxy groups contained in the epoxy resin) is not particularly limited. It is preferably in the range of 100 to 3,000.

  The thermal adhesive layer 116 is disposed on the innermost layer of the packaging material 110 and is made of a thermal adhesive resin that melts by heat and fuses the opposing packaging materials 110 to each other. The resin type differs depending on whether or not a tab film is interposed between the thermal adhesive layer 116 and the positive electrode tab 123a or the negative electrode tab 123b. When a tab film is interposed, a film made of a simple substance or a mixture of olefinic resins may be used. When no tab film is interposed, a film made of acid-modified polyolefin graft-modified with unsaturated carboxylic acid may be used.

  Also, polypropylene is preferably used as the thermal bonding layer 116. In addition, a film composed of a single layer or a multilayer of linear low density polyethylene and medium density polyethylene can be used. Moreover, the film which consists of a single layer or a multilayer which consists of a blend resin of linear low density polyethylene and medium density polyethylene can also be used.

  Moreover, each type of polypropylene can be used. For example, there are random propylene, homopropylene, block propylene and the like. Linear low-density polyethylene and medium-density polyethylene include a low-crystalline ethylene-butene copolymer, a low-crystalline propylene-butene copolymer, and a terpolymer composed of a three-component copolymer of ethylene, butene, and propylene. It may be added. Moreover, you may add antiblocking agents (AB agent), such as a silica, a zeolite, and an acrylic resin bead, and a fatty acid amide type slip agent to these resin.

  The acid-modified polyolefin layer 115 is a resin layer that stably bonds the barrier layer 114 and the thermal adhesive layer 116, and acid-modified polypropylene is preferably used. In addition, the acid-modified polyolefin layer 115 needs to be appropriately selected and used depending on the resin type used for the thermal bonding layer 116.

  For this reason, when using an acid-modified polyolefin other than acid-modified polypropylene, a polyolefin graft-modified with an unsaturated carboxylic acid, a copolymer of ethylene and acrylic acid graft-modified with an unsaturated carboxylic acid, or a graft modification with an unsaturated carboxylic acid Copolymer of propylene and acrylic acid, copolymer of ethylene and methacrylic acid graft-modified with unsaturated carboxylic acid, copolymer of propylene and methacrylic acid graft-modified with unsaturated carboxylic acid, unsaturated carboxylic acid There are metal cross-linked polyolefins grafted with acid.

  Further, 5% or more of a butene component, an ethylene-propylene-butene copolymer, an amorphous ethylene-propylene copolymer, a propylene-α-olefin copolymer, etc. may be added to these resins as necessary. Good.

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 adhesive layer 113 is a resin layer that firmly bonds the base material layer 112 and the barrier layer 114. 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 bonding by 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.

  According to this embodiment, the alumina particles and the modified epoxy resin contained in the chemical conversion treatment layer 114a have insulating properties, and are not easily melted or crushed by heat and pressure during heat sealing. As a result, even when burrs, carbon, or minute metal foreign matter bites into the thermal adhesive layer 116 during heat sealing, the burrs, carbon, or minute metal foreign matter are blocked by the chemical conversion treatment layer 114a and the metal foil of the barrier layer 116 Not reach. Thereby, it is possible to prevent a short circuit from occurring between the positive electrode tab 123a, the negative electrode tab 123b, and the barrier layer 114.

  In the present embodiment, different layers may be interposed between the layers. Moreover, although the lithium ion battery 121 is described, an electrochemical cell body other than the lithium ion battery body 122 may be packaged with a package 120 made of the packaging material 110 to produce an electric cell other than the lithium ion battery 121. .

  For example, the electrochemical cell includes a nickel metal hydride battery, a nickel cadmium battery, a lithium metal primary battery or secondary battery, a chemical battery such as a lithium polymer battery, an electric double layer capacitor, a capacitor, and an electrolytic capacitor in addition to a lithium ion battery. Here, the electrochemical cell body is 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. And all electric device elements that generate electric energy, such as a cell (power storage unit) including electrode terminals connected to a positive electrode and a negative electrode in the cell.

[Second Embodiment]
FIG. 4 is a cross-sectional view showing a packaging material 110 according to the second embodiment. For convenience of explanation, the same reference numerals are given to the same descriptions as those of the first embodiment shown in FIGS. In the packaging material 110 of this embodiment, an insulating layer 114b containing a modified epoxy resin is laminated on the chemical conversion treatment layer 114a on the thermal adhesive layer 116 side. As the modified epoxy resin used for the insulating layer 114b, the modified epoxy resin contained in the chemical conversion treatment layer 114a of the first embodiment can be used.

  According to this embodiment, the insulating property as a packaging material for an electrochemical cell is further improved by laminating the insulating layer 114b containing the modified epoxy resin on the chemical conversion treatment layer 114a formed on the thermal bonding layer 116 side. As a result, even if burrs, carbon, or minute metal foreign objects are caught between the aluminum of the barrier layer 114 and the positive electrode tab 123a and the negative electrode tab 123b, the burrs, carbon, or minute metal foreign objects are removed from the insulating layer 114b and the chemical conversion treatment. It is blocked by the layer 114a and does not reach the metal foil of the barrier layer 116. Thereby, it is possible to further prevent a short circuit from occurring between the positive electrode tab 123a, the negative electrode tab 123b, and the barrier layer 114.

  Note that the two-layer structure of the chemical conversion treatment layer 114a and the insulating layer 114b allows the laminate strength of the barrier layer 114 and the acid-modified polyolefin layer 115 to be higher than that when the chemical conversion treatment layer 114a is provided with a substantially equal thickness. The decrease can be suppressed.

  The insulating layer 114b preferably has a thickness of 0.5 μm to 5 μm. When the thickness of the insulating layer 114b is smaller than 0.5 μm, sufficient insulation cannot be obtained. On the other hand, when the thickness is larger than 5 μm, the laminate strength between the barrier layer 114 and the acid-modified polyolefin layer 115 is lowered. The thickness of the insulating layer 114b is more preferably larger than the particle size of the alumina particles contained in the chemical conversion treatment layer 114a.

  Next, the corrosion resistance and insulation were evaluated using the electrochemical cell packaging material 110 of Example 1 and Example 2 according to the above embodiment and the electrochemical cell packaging material of Comparative Example 1.

  The electrochemical cell packaging material 110 according to Example 1 is subjected to a chemical conversion treatment on both surfaces of aluminum (thickness 40 μm), and a stretched nylon film (thickness 25 μm) is bonded to one chemical conversion treatment surface with a two-component curable polyurethane adhesive. It bonded together by the dry lamination method through the agent. Next, acid-modified polypropylene (thickness: 23 μm, hereinafter abbreviated as acid-modified PP) and polypropylene (thickness: 23 μm, hereinafter abbreviated as PP) were coextruded and laminated on the other chemical conversion treated surface.

At this time, for the chemical conversion treatment, a treatment liquid composed of a mixed liquid of alumina particles having an average particle diameter of 0.2 μm, phosphoric acid, and a resin component (aminated phenol: modified epoxy resin = 1: 1) was used. Further, the treatment liquid was applied by a roll coating method and baked for 2 minutes under the condition that the film temperature was 190 ° C. Further, the coating amount of the treatment liquid was 1 g / m ² (dry weight), and the thickness of the chemical conversion treatment layer 114a after drying was formed to 1 μm.

  Thereby, a stretched nylon film corresponding to the base material layer 112 / a two-component curable polyurethane adhesive corresponding to the adhesive layer 113 / a chemical conversion treatment layer 114a corresponding to the barrier layer 114 / a chemical conversion treatment layer 114a / acid-modified polyolefin. A packaging material 110 for an electrochemical cell according to Example 1 composed of an acid-modified PP corresponding to the layer 115 and a PP corresponding to the thermal adhesive layer 116 was obtained.

  The electrochemical cell packaging material 110 according to Example 2 is subjected to a chemical conversion treatment on both surfaces of aluminum (thickness 40 μm), and a stretched nylon film (thickness 25 μm) is bonded to one chemical conversion treatment surface with a two-component curable polyurethane adhesive. It bonded together by the dry lamination method through the agent. Next, acid-modified polypropylene (thickness: 23 μm, hereinafter abbreviated as acid-modified PP) and polypropylene (thickness: 23 μm, hereinafter abbreviated as PP) were coextruded and laminated on the other chemical conversion treated surface.

At this time, for the chemical conversion treatment, a treatment liquid composed of a mixed liquid of alumina particles having an average particle diameter of 0.2 μm, phosphoric acid and a resin component (modified epoxy resin) was used. Further, the treatment liquid was applied by a roll coating method and baked for 2 minutes under the condition that the film temperature was 190 ° C. Further, the coating amount of the treatment liquid was 1 g / m ² (dry weight), and the thickness of the chemical conversion treatment layer 114a after drying was formed to 1 μm.

  Thereby, a stretched nylon film corresponding to the base material layer 112 / a two-component curable polyurethane adhesive corresponding to the adhesive layer 113 / a chemical conversion treatment layer 114a corresponding to the barrier layer 114 / a chemical conversion treatment layer 114a / acid-modified polyolefin. A packaging material 110 for an electrochemical cell according to Example 2 composed of an acid-modified PP corresponding to the layer 115 and a PP corresponding to the thermal adhesive layer 116 was obtained.

[Comparative Example 1]
The electrochemical cell packaging material according to Comparative Example 1 is subjected to a chemical conversion treatment on both surfaces of aluminum (thickness 40 μm), and a two-component curable polyurethane adhesive with a stretched nylon film (thickness 25 μm) on one chemical conversion treatment surface. And bonded together by a dry laminating method. Next, acid-modified polypropylene (thickness: 23 μm, hereinafter abbreviated as acid-modified PP) and polypropylene (thickness: 23 μm, hereinafter abbreviated as PP) were coextruded and laminated on the other chemical conversion treated surface.

At this time, for the chemical conversion treatment, a treatment liquid comprising a mixed liquid of alumina particles having an average particle diameter of 0.2 μm, phosphoric acid and a resin component (aminated phenol) was used. Further, the treatment liquid was applied by a roll coating method and baked for 2 minutes under the condition that the film temperature was 190 ° C. Further, the coating amount of the treatment liquid was 1 g / m ² (dry weight), and the thickness of the chemical conversion treatment layer after drying was formed to 1 μm.

  Thus, stretched nylon film corresponding to the base material layer / two-component curable polyurethane adhesive corresponding to the adhesive layer / chemical conversion treatment layer / aluminum equivalent to the barrier layer / acid corresponding to the acid-modified polyolefin layer A packaging material for an electrochemical cell according to Example 1 composed of PP corresponding to a modified PP / thermal adhesive layer was obtained.

  The corrosion resistance was evaluated by cutting the packaging materials according to Example 1, Example 2 and Comparative Example 1 into strips of 15 mm × 100 mm, and then using an electrolytic solution at 85 ° C. (ethylene carbonate: diethyl carbonate: dimethyl carbonate = 1: 1 mol of lithium hexafluorophosphate was added to the 1: 1 solution) and immersed in the electrolyte for 2 weeks.

  Next, after each portion of the packaging material after pickling, a part of PP which is a thermal adhesive layer is peeled off, and then peeled off using a pulling machine (manufactured by Shimadzu Corporation, AGS-50D (trade name)). PP was further peeled from the packaging material in the longitudinal direction at a speed of 50 mm / min, and the strength at the time of taking was measured. This was performed for five samples, and the average value was used as the laminate strength (N / 15 mm). At this time, when the laminate strength was larger than 5 N / 15 mm, it was judged that the corrosion resistance against the electrolytic solution was excellent (◯). Further, when the laminate strength was smaller than 5 N / 15 mm, it was judged that the corrosion resistance against the electrolytic solution was low (x). The results are shown in Table 1.

  Insulation evaluation is performed by evaluating the moldability of the packaging material according to Example 1, Example 2 and Comparative Example 1 after cutting into 15 mm × 100 mm strips and then covering the surface with nickel particles having an average particle size of 44 μm The tab (4 mm × 30 mm) and PP of the packaging material were brought into contact with each other, and heat sealed while being pressed (0.2 MPa, 190 ° C.) with a heat seal bar (width 30 mm).

  At this time, the carbon particles are bitten into the acid-modified PP and PP by pressing the heat seal bar, and heat sealing is continued until the resistance value between the nickel tab and the aluminum of the packaging material becomes 100Ω or less at a voltage of 25 V. It was measured. This was carried out for 5 samples, and the average value was taken as the time (seconds) until the decrease in insulation, and when the time until the decrease in insulation was 100 seconds or more, it was judged that the insulation was excellent (◯). In addition, when the time until the decrease in insulation was 20 seconds or more and less than 100 seconds, it was determined that the medium had insulation (Δ). In addition, when the time until the decrease in insulation was less than 20 seconds, it was determined that the insulation was low (x). The results are shown in Table 1.

  As shown in Table 1, the packaging materials according to Example 1, Example 2, and Comparative Example 1 were excellent in corrosion resistance against the electrolytic solution (◯). In addition, when the packaging material after pickling was observed visually, the packaging material which concerns on Example 1, Example 2, and a comparative example did not observe the float by the delamination between aluminum and a resin layer. Moreover, the packaging material 110 which concerns on Example 1 and Example 2 was excellent in insulation ((circle)). On the other hand, the packaging material according to Comparative Example 1 had low insulation (x).

  INDUSTRIAL APPLICABILITY The present invention can be used as a 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 Packaging material 111a Filler 112 Base material layer 113 Adhesion layer 114 Barrier layer 114a Chemical conversion treatment layer 114b Insulation layer 115 Acid-modified polyolefin layer 116 Thermal adhesion layer 120 Package 120a Storage part 120b Sheet part 121 Lithium ion battery 122 Lithium ion battery main body 123a Positive electrode tab 123b Negative electrode tab

Claims (3)

A base layer composed of at least a resin film; a thermal adhesive layer composed of a thermoadhesive resin disposed in the innermost layer; a barrier layer composed of a metal foil disposed between the base material layer and the thermal adhesive layer; the a packaging material for electrochemical cell formed by laminating, chemical conversion layer containing alumina particles and a modified epoxy resin on the surface of at least the heat-adhesive layer side of the barrier layer is formed, the heat A packaging material for an electrochemical cell, wherein an insulating layer containing a modified epoxy resin is laminated on the chemical conversion layer formed on the adhesive layer side . The electrochemical cell packaging material according to claim 1, wherein the insulating layer has a thickness of 0.5 µm or more and 5 µm or less . Claim 1 or packaging material for electrochemical cell according to claim 2 the thickness of the insulating layer being greater than the diameter of the alumina particles.

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