JP6379631B2 - Power storage device exterior material and power storage device - Google Patents

Description

  The present invention relates to an exterior material for a power storage device and a power storage device.

  As power storage devices, for example, secondary batteries such as lithium ion batteries, nickel metal hydride, and lead storage batteries, and electrochemical capacitors such as electric double layer capacitors are known. There is a demand for further miniaturization of power storage devices due to miniaturization of portable devices or limitations on installation space, and lithium ion batteries with high energy density are attracting attention. Conventionally, metal cans have been used as exterior materials used in lithium ion batteries, but multilayer films that are lightweight, have high heat dissipation properties, and can be handled at low cost are being used.

  In a lithium ion battery using the multilayer film as an exterior material, the battery contents (positive electrode, separator, negative electrode, electrolyte, etc.) are covered with an exterior material including an aluminum foil layer in order to prevent moisture from entering the interior. It has been adopted. A lithium ion battery employing such a configuration is called an aluminum laminate type lithium ion battery.

  An aluminum laminate type lithium ion battery, for example, forms a recess in a part of the exterior material by cold molding, accommodates the battery contents in the recess, folds the remaining part of the exterior material, and heats the edge portion. An embossed type lithium ion battery sealed with a seal is known (hereinafter also referred to as “one-side molded battery”). In recent years, for the purpose of increasing energy density, a lithium-ion battery (hereinafter referred to as “both-side molded battery”) in which recesses are formed on both sides of an exterior material to be bonded to accommodate more battery contents. Is also manufactured. The double-sided molded battery has a problem that it is difficult to align the exterior materials together. However, in order to obtain an energy density equivalent to that of the both-side molded battery in the one-side molded battery, it is necessary to form a deeper recess.

The energy density of a lithium ion battery increases as the recesses formed by cold forming become deeper. However, the deeper the concave portion to be formed, the easier the pinhole or breakage occurs in the outer packaging material during molding, and the moldability is degraded. Therefore, as an example of improvement in moldability, the base material layer has a tensile strength of 150 N / mm ² until breakage in four directions of 0 °, 45 °, 90 °, and 135 °, and elongation in the four directions. It has been proposed to use a film having a thickness of 80% or more (Patent Document 1).

  Moreover, in order to improve moldability, the metal foil is protected by using a biaxially stretched polyamide film for the base material layer of the exterior material. However, the biaxially stretched polyamide film has low resistance to the electrolyte solution that is the content of the lithium ion battery, and the electrolyte solution adheres to the biaxially stretched polyamide film during the injection of the electrolyte solution in the manufacturing process of the lithium ion battery. In this case, the biaxially stretched polyamide film is dissolved, resulting in poor appearance.

  Therefore, as an exterior material having an electrolyte solution resistance on the surface of the base material layer, a biaxially stretched nylon film (hereinafter sometimes referred to as “biaxially stretched Ny film”) and a biaxially stretched polyethylene laminated further on the outside. An exterior material using a terephthalate film (hereinafter sometimes referred to as “biaxially stretched PET film”) as a base material layer has been proposed (Patent Document 2).

Japanese Patent No. 3567230 Japanese Patent No. 4559547

  However, when deep drawing molding is performed in which a recess is formed in such an exterior material, the exterior material after molding may be greatly warped toward the base material layer side. Such a tendency is particularly remarkable when a one-side molded battery is manufactured. The warping of the exterior material is considered to occur when the stretched base material layer tries to return to the original state when the exterior material is molded while being stretched, and the exterior material obtained in Patent Documents 1 and 2 It was difficult to solve the above-mentioned warp problem with the material. The inventor believes that the reason is as follows. That is, in the exterior materials of Patent Documents 1 and 2, a metal foil layer is sandwiched, and a base material layer using a polyester film or a polyamide film or the like is disposed on one side thereof, and a heat adhesive property such as an acid-modified polyolefin resin or the like is disposed on the other side. Although the resin layer is arranged, the base material layer has a tensile strength in the elastic region (region that recovers to the original length when the load is removed) in the tensile test compared to the heat-adhesive resin layer. This is remarkably large, and it is considered that the force to return to the original with respect to stretching by the molding process is larger on the base material layer side.

  The warping after the molding process causes a suction error when the exterior material is sucked and conveyed to the next process or the like, or causes a heat seal failure at the time of heat sealing that is the next process.

  The present invention has been made in view of the above circumstances, and provides a power storage device exterior material capable of reducing warpage after molding while maintaining excellent moldability, and a power storage device using the same. The purpose is to do.

  In order to achieve the above object, the present invention comprises a first base material layer, a second base material layer formed on one surface of the first base material layer via a first adhesive layer, A metal foil layer formed on a surface opposite to the first base material layer of the two base material layers via a second adhesive layer, and a surface of the metal foil layer opposite to the second base material layer An aliphatic group obtained by reacting an aliphatic polymer having two or more hydroxyl groups or two or more acid anhydride groups with an aliphatic polyisocyanate. An exterior material for a power storage device including a polyurethane resin is provided.

  Thus, the first adhesive layer contains the aliphatic polyurethane resin obtained by reacting the aliphatic polymer and the aliphatic polyisocyanate, thereby reducing the tensile strength on the base material layer side with the metal foil layer interposed therebetween. Thus, the tensile strength on the sealant layer side can be brought close to the metal foil layer, and as a result, the warpage after molding can be suppressed while maintaining excellent moldability. This is because the aliphatic polymer is mainly composed of a single bond between carbon and carbon, and thus is excellent in flexibility and flexibility compared to the aromatic polymer. Furthermore, yellowing can be suppressed and weather resistance can be improved by using an aliphatic polyisocyanate.

  In the said exterior material, it is preferable that said 2nd contact bonding layer contains an aromatic polyurethane resin from a moldable viewpoint.

  In the exterior material, the first base material layer is preferably a stretched polyester film, and the second base material layer is preferably a stretched polyamide film. When the first base material layer and the second base material layer have the above configuration, both excellent moldability and electrolyte solution resistance can be achieved.

  In the exterior material, the thickness of the first base material layer is preferably 4 μm or more and 20 μm or less, and the thickness of the second base material layer is preferably 5 μm or more and 30 μm or less. When the first base material layer and the second base material layer have the above-described configuration, it is possible to manufacture a power storage device that has both excellent moldability and high energy density.

  The present invention also provides a base material layer, a metal foil layer formed on one surface of the base material layer via a first adhesive layer, and a surface of the metal foil layer opposite to the base material layer. An aliphatic group obtained by reacting an aliphatic polymer having two or more hydroxyl groups or two or more acid anhydride groups with an aliphatic polyisocyanate. An exterior material for a power storage device including a polyurethane resin is provided.

  Thus, the first adhesive layer contains the aliphatic polyurethane resin obtained by reacting the aliphatic polymer and the aliphatic polyisocyanate, thereby reducing the tensile strength on the base material layer side with the metal foil layer interposed therebetween. Thus, the tensile strength on the sealant layer side can be brought close to the metal foil layer, and as a result, the warpage after molding can be suppressed while maintaining excellent moldability. This is because the aliphatic polymer is mainly composed of a single bond between carbon and carbon, and thus is excellent in flexibility and flexibility compared to the aromatic polymer. Furthermore, yellowing can be suppressed and weather resistance can be improved by using an aliphatic polyisocyanate.

  In the exterior material, the base material layer is preferably a stretched polyamide film. When the base material layer has the above-described configuration, excellent electrolyte resistance can be obtained.

  In the said exterior material, it is preferable that the thickness of the said base material layer is 5 micrometers or more and 30 micrometers or less. When the base material layer has the above-described configuration, it is possible to manufacture a power storage device having excellent moldability and high energy density.

  In any of the above exterior materials, the aliphatic polyurethane resin is preferably obtained by reacting an aliphatic polymer having two or more hydroxyl groups with an aliphatic polyisocyanate. In any of the above exterior materials, the aliphatic polyurethane resin is obtained by reacting an aliphatic polyester having two or more hydroxyl groups or two or more acid anhydride groups with an aliphatic polyisocyanate. Is preferred. In the first adhesive layer, when the aliphatic polyurethane resin has the above-described configuration, warpage after molding can be further reduced.

  The present invention also relates to a power storage device as another aspect. The power storage device includes a battery element including an electrode, a lead extending from the electrode, and a container that accommodates the battery element, and the container has the sealant layer inside from the power storage device exterior material. It is formed as follows. In this case as well, the warpage after the molding process can be reduced while maintaining excellent moldability as in the case of the exterior material for a power storage device.

  ADVANTAGE OF THE INVENTION According to this invention, the exterior material for electrical storage apparatuses which can reduce the curvature after a shaping | molding process, maintaining the outstanding moldability, and an electrical storage apparatus using the same can be provided.

It is a schematic sectional drawing of the exterior material for electrical storage apparatuses which concerns on one Embodiment of this invention. It is a schematic sectional drawing of the exterior material for electrical storage apparatuses which concerns on another embodiment of this invention. It is a figure which shows the embossing type exterior material obtained using the exterior material for electrical storage devices which concerns on one Embodiment of this invention, (a) is the perspective view, (b) is the embossing shown to (a). It is a longitudinal cross-sectional view along the bb line of the type exterior material. It is a perspective view which shows the process of manufacturing a secondary battery using the exterior material for electrical storage devices which concerns on one Embodiment of this invention, (a) shows the state which prepared the exterior material for electrical storage devices, (b) Is a state in which an exterior material for a power storage device processed into an embossed type and a battery element are prepared, and (c) is a state in which a part of the exterior material for a power storage device is folded and an end is melted. ) Shows a state where both sides of the folded portion are folded upward.

  Hereinafter, embodiments of the present invention will be described in detail. In addition, this invention is not limited to the following embodiment.

[Exterior Material 10 for Power Storage Device]
First, a power storage device exterior material 10 (hereinafter also simply referred to as “exterior material 10”) according to an embodiment of the present invention will be described. The exterior material 10 covers battery elements such as a positive electrode, a separator, a negative electrode, and an electrolytic solution, and prevents moisture from entering the battery, or a substance generated inside (for example, hydrofluoric acid generated by moisture penetration) ) Is a packaging material for preventing leakage to the outside. As shown in FIG. 1, such an exterior material 10 includes a first base material layer 11 and a second base material formed on one surface of the first base material layer 11 via a first adhesive layer 12. A layer 13, a metal foil layer 15 formed on the surface of the second substrate layer 13 opposite to the first substrate layer 11 via a second adhesive layer 14, and a second substrate of the metal foil layer 15 A sealant layer 18 disposed on a surface opposite to the layer 13 is provided as a basic configuration. In the exterior material 10, the corrosion prevention treatment layer 16 formed on the surface of the metal foil layer 15 opposite to the second base material layer 13 between the metal foil layer 15 and the sealant layer 18, and the corrosion prevention treatment. A sealant adhesive layer 17 formed on the surface of the layer 16 opposite to the metal foil layer 15 may be provided. In this case, the exterior material 10 includes a first base material layer 11, a first adhesive layer 12, a second base material layer 13, a second adhesive layer 14, a metal foil layer 15, a corrosion prevention treatment layer 16, a sealant adhesive layer 17, and This is a laminate in which the sealant layers 18 are sequentially laminated.

(First base material layer 11)
The first base material layer 11 imparts heat resistance to the exterior material 10 in a pressurization thermal fusion process, which will be described later when manufacturing the power storage device, to suppress the occurrence of pinholes that may occur during processing or distribution. Layer. The first base material layer 11 includes, for example, a polyester resin, a polyamide resin, a polyolefin resin, a polyimide resin, and a polycarbonate resin, and preferably includes a polyester resin.

  The first base material layer 11 may further include a polyester elastomer or an amorphous polyester. When the first base material layer 11 includes the polyester elastomer or the amorphous polyester, the elastic region with respect to the tensile stress during the molding process is reduced, the shrinkage rate of the stretched part by the molding process is reduced, and the warp after molding The amount can be reduced.

  The polyester elastomer is composed of a hard segment and a soft segment. Examples of the hard segment include crystalline polyesters such as polybutylene terephthalate, polybutylene naphthalate, and polyethylene terephthalate, and the hard segment is preferably polybutylene terephthalate. Examples of the soft segment include polyoxyalkylene glycols such as polytetramethylene glycol, and polyesters such as polycaprolactone and polybutylene adipate. The soft segment is preferably polytetramethylene glycol. The amorphous polyester can be obtained, for example, by changing a part of ethylene glycol when producing the polyester to cyclohexanedimethanol.

  The first base material layer 11 configured to contain a polyester resin is more preferably a stretched polyester film, and more preferably a biaxially stretched polyethylene terephthalate (PET) film from the viewpoint of excellent puncture strength or impact strength. preferable.

  The thickness of the first base material layer 11 is preferably 4 μm to 20 μm, and more preferably 10 μm to 15 μm. When the thickness of the 1st base material layer 11 is 20 micrometers or less, the increase in the contraction rate of the 1st base material layer 11 of the location extended | stretched by the shaping | molding process can be suppressed, and the curvature after a shaping | molding process can be reduced. Moreover, the protective effect of a metal foil layer improves because the thickness of the 1st base material layer 11 is 4 micrometers or more.

(First adhesive layer 12)
The first adhesive layer 12 is a layer that bonds the first base material layer 11 and the second base material layer 13 together. The adhesive used for the first adhesive layer 12 includes a main component of an aliphatic polymer having two or more hydroxyl groups or two or more acid anhydride groups, and a curing agent for an aliphatic polyisocyanate having two or more isocyanate groups. The first adhesive layer 12 contains an aliphatic polyurethane resin obtained by reacting the aliphatic polymer with the aliphatic polyisocyanate. The aliphatic urethane adhesive is mainly composed of an aliphatic compound and does not contain an aromatic compound. The aliphatic polymer preferably has two or more hydroxyl groups. The aliphatic polymer is preferably an aliphatic polyester having two or more hydroxyl groups or two or more acid anhydride groups from the viewpoint of improving moldability by contributing to network formation between adhesives. In the first adhesive layer, when the polyurethane resin is obtained from an aliphatic polymer having the above configuration, warpage after molding can be further reduced. Further, if the entire system of the adhesive layer is limited to the aliphatic compound, the glass transition temperature (Tg) of the entire system can be lowered, and the low temperature characteristics of the adhesive layer can be maintained at a high level. The above aliphatic urethane-based adhesive is subjected to aging at, for example, 40 ° C. for 4 days or more after coating, so that the reaction between the hydroxyl group or acid anhydride group of the main agent and the isocyanate group of the curing agent proceeds. Strong adhesion between the material layer 11 and the second base material layer 13 becomes possible.

  Examples of the aliphatic polymer include aliphatic polyester polyols, aliphatic polyether polyols, aliphatic polymers having two or more hydroxyl groups such as aliphatic polyols whose main chain is composed of carbon-carbon bonds, or aliphatic polyolefins. It is preferably an aliphatic polymer having two or more acid anhydride groups such as an acid anhydride-modified polyolefin resin obtained by graft-modifying a resin with an acid anhydride such as maleic anhydride.

  The aliphatic polyester polyol is a reaction product of a fatty acid and a polyol. Examples of the fatty acid include ricinoleic acid, oxycaproic acid, oxycapric acid, oxyundecanoic acid, oxylinoleic acid, oxystearic acid, and oxyhexanedecene. Examples include acid-containing hydroxyl group-containing long chain fatty acids. The fatty acid preferably has 5 to 20 carbon atoms. Moreover, although the said fatty acid may be either linear or branched, it is preferable that it is linear from a viewpoint which is excellent in a softness | flexibility. Examples of polyols that react with fatty acids include glycols such as ethylene glycol, propylene glycol, butylene glycol, hexamethylene glycol and diethylene glycol, trifunctional polyols such as glycerin, trimethylolpropane and triethanolamine, and tetrafunctionals such as diglycerin and pentaerythritol. Examples thereof include hexafunctional polyols such as polyol and sorbitol, and octafunctional polyols such as sugar.

  Examples of the aliphatic polyether polyol include addition polymers of polyol and alkylene oxide. Examples of the polyol include bifunctional polyols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, and 1,4-butanediol, and glycerin, 1,1,1-trimethylolpropane, Examples include trivalent or higher polyols such as 1,2,5-hexanetriol and pentaerythritol. Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, and α-olefin oxide.

  Examples of the aliphatic polyol whose main chain is composed of carbon-carbon bonds include polybutadiene polyol, polyisoprene polyol, hydrogenated polybutadiene polyol, and polyol obtained by graft polymerization of AN (acrylonitrile). Examples of other aliphatic polyols include acrylic polyol, polycarbonate polyol, and PTMG (polytetramethylene glycol).

  Examples of the aliphatic polyolefin resin used in the acid anhydride-modified aliphatic polyolefin resin include ethylene, propylene, butene, pentene, hexene, heptene, octene, and 4-methyl-1-pentene. It is a polymer of 2 or more and 6 or less olefin.

  The lower limit of the number average molecular weight of the aliphatic polymer is preferably 500, more preferably 1000. When the number average molecular weight of the aliphatic polymer is 500 or more, residual unreacted substances in the adhesive can be further reduced. Moreover, the upper limit of the number average molecular weight of the aliphatic polymer is preferably 30000, more preferably 10,000. When the number average molecular weight of the aliphatic polymer is 30000 or less, flexibility as an adhesive can be obtained. In addition, the said number average molecular weight is a measured value by GPC (gel permeation chromatography), and made the eluent tetrahydrofuran and measured on the polystyrene basis.

  The aliphatic polyisocyanate is a compound having two or more isocyanate groups, and the molecular weight of the aliphatic polyisocyanate is preferably 100 to 5,000. Examples of the aliphatic polyisocyanate include hexamethylene diisocyanate (HDI).

  The aliphatic polyurethane resin is obtained by aging (curing) the aliphatic urethane-based adhesive containing the aliphatic polymer and the aliphatic polyisocyanate at a temperature of 40 ° C. or higher and 100 ° C. or lower for 4 days or longer.

  The aliphatic polyurethane resin is preferably obtained by reacting 1 to 50 parts by mass of the aliphatic polyisocyanate with respect to 100 parts by mass of the aliphatic polymer, and more preferably 2 to 30 parts by mass. . By causing the aliphatic polyisocyanate to react with the above lower limit or more, it is possible to obtain strong adhesiveness. Further, by causing the aliphatic polyisocyanate to react below the upper limit, it is possible to minimize side reactions between the unreacted curing agent and moisture in the atmosphere.

  The aliphatic polyurethane resin has a glass transition point (Tg) measured by differential scanning calorimetry (DSC) of preferably 0 to 45 ° C, more preferably 5 to 40 ° C. When the glass transition point is 0 ° C. or higher, tackiness of the adhesive can be reduced and adhesion of foreign matters can be suppressed. On the other hand, when the glass transition point is 45 ° C. or lower, more excellent adhesive force can be obtained.

  The thickness of the first adhesive layer 12 is preferably 1 to 5 μm. When the thickness of the first adhesive layer is 1 μm or more, sufficient adhesive strength between the first base material layer 11 and the second base material layer 13 is easily obtained, and when the thickness is 5 μm or less, the first adhesive layer The occurrence of 12 cracks can be suppressed.

(Second base material layer 13)
The 2nd base material layer 13 is a layer for preventing the outflow of the substance (for example, hydrofluoric acid etc. which generate | occur | produces by penetration | invasion of a water | moisture content) generated inside a battery outside. The second base material layer 13 is preferably configured to include a polyamide resin (nylon) or a polyester resin that is thin, has a high strength, has a large elongation, and is soft in order to perform molding with a thin shape. .

  The second base material layer 13 including the polyamide resin is preferably a stretched polyamide film, and more preferably a biaxially stretched nylon (ONy) film from the viewpoint of excellent puncture strength or impact strength.

  The thickness of the second base material layer 13 is preferably 5 μm to 30 μm, and more preferably 15 μm to 25 μm. When the thickness of the second base material layer 13 is 5 μm or more, excellent moldability is obtained, and when it is 30 μm or less, the energy density of the power storage device can be increased.

(Second adhesive layer 14)
The second adhesive layer 14 is a layer that bonds the second base material layer 13 and the metal foil layer 15 together. The adhesive constituting the second adhesive layer 14 may be either an aliphatic urethane adhesive or an aromatic urethane adhesive, but is preferably an aromatic urethane adhesive. The aromatic urethane-based adhesive contains an aromatic compound in at least one of the main agent and the curing agent, for example, a main agent such as polyester polyol, polyether polyol, and acrylic polyol, and a curing agent for a bifunctional or higher-functional aromatic polyisocyanate. including. It is preferable that the 2nd contact bonding layer 14 contains the aromatic polyurethane resin obtained by making a polyol and aromatic polyisocyanate react from a moldable viewpoint. After applying the urethane adhesive, for example, by performing aging for 4 days or more at 40 ° C. or more and 100 ° C. or less, the reaction between the hydroxyl group of the main agent and the isocyanate group of the curing agent proceeds and strong adhesion is possible. Become.

  The thickness of the second adhesive layer 14 is preferably 1 to 10 μm and more preferably 3 to 7 μm from the viewpoints of adhesive strength, followability, workability, and the like.

(Metal foil layer 15)
Examples of the metal foil layer 15 include various metal foils such as aluminum and stainless steel, and the metal foil layer 15 is preferably an aluminum foil from the viewpoint of workability such as moisture resistance and spreadability, and cost. The aluminum foil may be a general soft aluminum foil, and is preferably an aluminum foil containing iron from the viewpoint of excellent pinhole resistance and extensibility during molding.

  The content of iron in the aluminum foil containing iron (100% by mass) is preferably 0.1 to 9.0% by mass, and more preferably 0.5 to 2.0% by mass. When the iron content is 0.1% by mass or more, it is possible to obtain the exterior material 10 having more excellent pinhole resistance and spreadability. When the iron content is 9.0% by mass or less, it is possible to obtain the exterior material 10 having more flexibility.

  The thickness of the metal foil layer 15 is preferably 9 to 200 μm and more preferably 15 to 100 μm from the viewpoint of barrier properties, pinhole resistance and workability. When the thickness of the metal foil layer 15 is 9 μm or more, the metal foil layer 15 is not easily broken even when stress is applied by molding. When the thickness of the metal foil layer 15 is 200 μm or less, an increase in mass of the exterior material can be reduced, and a decrease in weight energy density of the power storage device can be suppressed.

(Corrosion prevention treatment layer 16)
The corrosion prevention treatment layer 16 serves to suppress the corrosion of the metal foil layer 15 due to the electrolytic solution or hydrofluoric acid generated by the reaction between the electrolytic solution and moisture. Further, it plays a role of increasing the adhesion between the metal foil layer 15 and the sealant adhesive layer 17.

  The corrosion prevention treatment layer 16 is preferably a coating film formed by a coating type or immersion type acid resistant corrosion prevention treatment agent. This coating film is excellent in the effect of preventing corrosion of the metal foil layer 15 against acid. Moreover, since the adhesive force between the metal foil layer 15 and the sealant adhesive layer 17 is further strengthened by the anchor effect, excellent resistance to power storage device elements such as an electrolytic solution can be obtained. Further, the corrosion prevention treatment layer 16 may be added between the first adhesive layer 12 and the metal foil layer 15 according to a required function.

  The coating film of the corrosion inhibitor is, for example, ceriazol treatment with a corrosion inhibitor consisting of cerium oxide, phosphate and various thermosetting resins, and chromate, phosphate, fluoride and various thermosets. Formed by a chromate treatment with a corrosion prevention treatment agent composed of a conductive resin. The corrosion prevention treatment layer 16 is not limited to the above-described coating film as long as the corrosion resistance of the metal foil layer 15 is sufficiently obtained. The corrosion prevention treatment layer 16 may be a coating film formed by, for example, a phosphate treatment and a boehmite treatment.

  The corrosion prevention treatment layer 16 may be a single layer or a plurality of layers. In addition, an additive such as a silane coupling agent may be added to the corrosion prevention treatment layer 16. The thickness of the corrosion prevention treatment layer 16 is, for example, preferably from 10 nm to 5 μm, and more preferably from 20 to 500 nm, from the viewpoint of the corrosion prevention function and the function as an anchor.

(Sealant adhesive layer 17)
The sealant adhesive layer 17 is a layer for bonding the metal foil layer 15 on which the corrosion prevention treatment layer 16 is formed and the sealant layer 18. The exterior material 10 is roughly divided into a thermal laminate configuration and a dry laminate configuration depending on the adhesive component that forms the sealant adhesive layer 17.

  The adhesive component forming the sealant adhesive layer 17 in the heat laminate configuration is preferably an acid-modified polyolefin resin obtained by graft-modifying a polyolefin resin with an acid. Since the acid-modified polyolefin-based resin has a polar group introduced into a part of the non-polar polyolefin-based resin, the acid-modified polyolefin-based resin has a polarity with the sealant layer 18 formed of a non-polar polyolefin-based resin film or the like. In many cases, it can be firmly adhered to both of the corrosion prevention treatment layers 16. In addition, by using an acid-modified polyolefin-based resin, the resistance of the exterior material 10 to the contents such as the electrolyte solution is improved, and even if hydrofluoric acid is generated inside the battery, the adhesion is reduced due to deterioration of the sealant adhesive layer 17. It is easy to prevent.

  Examples of the polyolefin resin of the acid-modified polyolefin resin include low density, medium density and high density polyethylene; ethylene-α olefin copolymer; polypropylene; and propylene-α olefin copolymer. The polyolefin resin in the case of a copolymer may be a block copolymer or a random copolymer. Further, as the polyolefin resin, a copolymer obtained by copolymerizing a polar molecule such as acrylic acid or methacrylic acid with the above-described one, or a polymer such as a crosslinked polyolefin can be used. Examples of the acid that modifies the polyolefin resin include carboxylic acid, epoxy compound, and acid anhydride, and maleic anhydride is preferable. The acid-modified polyolefin resin used for the sealant adhesive layer 17 may be one type or two or more types.

  The heat-bonded sealant adhesive layer 17 can be formed by extruding the adhesive component with an extrusion device. The thickness of the heat-bonded sealant adhesive layer 17 is preferably 2 to 50 μm.

  As an adhesive component for forming the sealant adhesive layer 17 having a dry laminate structure, for example, a two-component curable polyurethane adhesive similar to that described for the first adhesive layer 12 or the second adhesive layer 14 may be used.

  Since the sealant adhesive layer 17 having a dry laminate structure has a highly hydrolyzable bonding portion such as an ester group and a urethane group, a heat laminate structure is used as the sealant adhesive layer 17 for applications requiring higher reliability. It is preferable to use the adhesive component.

  In the case of a heat laminate configuration, the thickness of the sealant adhesive layer 17 is preferably 8 μm or more and 30 μm or less, and more preferably 10 μm or more and 20 μm or less. When the thickness of the sealant adhesive layer 17 is 8 μm or more, sufficient adhesive strength between the metal foil layer 15 and the sealant layer 18 can be easily obtained. It is possible to easily reduce the amount of moisture that enters. The thickness of the sealant adhesive layer 17 is preferably 1 μm or more and 5 μm or less in the case of a dry laminate configuration. When the thickness of the sealant adhesive layer 17 is 1 μm or more, sufficient adhesion strength between the metal foil layer 15 and the sealant layer 18 is easily obtained, and when the thickness is 5 μm or less, the sealant adhesive layer 17 is not cracked. Can be suppressed.

(Sealant layer 18)
The sealant layer 18 is a layer that imparts sealing properties to the exterior material 10 by heat sealing. Examples of the sealant layer 18 include a polyolefin resin or a resin film made of an acid-modified polyolefin resin obtained by graft-modifying an acid such as maleic anhydride to a polyolefin resin.

  Examples of the polyolefin-based resin include low density, medium density and high density polyethylene; ethylene-α olefin copolymer; polypropylene; and propylene-α olefin copolymer. The polyolefin resin in the case of a copolymer may be a block copolymer or a random copolymer. These polyolefin resin may be used individually by 1 type, and may use 2 or more types together.

  Examples of the acid-modified polyolefin-based resin include those similar to those exemplified in the sealant adhesive layer 17.

  The sealant layer 18 may be a single layer film or a multilayer film, and may be selected according to a required function. For example, in terms of imparting moisture resistance, a multilayer film in which a resin such as an ethylene-cyclic olefin copolymer and polymethylpentene is interposed can be used.

  The sealant layer 18 may contain various additives such as a flame retardant, a slip agent, an antiblocking agent, an antioxidant, a light stabilizer, and a tackifier.

  The thickness of the sealant layer 18 is preferably 10 to 100 μm, and more preferably 20 to 60 μm. When the thickness of the sealant layer 18 is 20 μm or more, sufficient heat seal strength can be obtained, and when it is 90 μm or less, the amount of water vapor entering from the edge of the exterior material can be reduced.

[Exterior Material 20 for Power Storage Device]
Next, a power storage device exterior material 20 (hereinafter also simply referred to as “exterior material 20”) according to another embodiment of the present invention will be described. The packaging material 20 covers battery elements such as a positive electrode, a separator, a negative electrode, and an electrolytic solution to prevent moisture from entering the battery, or a substance generated inside (for example, hydrofluoric acid generated by moisture penetration) ) Is a packaging material for preventing leakage to the outside. As shown in FIG. 2, such an exterior material 20 includes a base material layer 21, a metal foil layer 23 formed on one surface of the base material layer 21 via a first adhesive layer 22, and a metal foil. The sealant layer 26 disposed on the surface of the layer 23 opposite to the base material layer 21 is provided as a basic configuration. In the exterior material 20, a corrosion prevention treatment layer 24 and a corrosion prevention treatment layer 24 formed between the metal foil layer 23 and the sealant layer 26 on the surface opposite to the base material layer 21 of the metal foil layer 23. A sealant adhesive layer 25 formed on the surface opposite to the metal foil layer 23 may be provided. In this case, the exterior material 20 is a laminate in which a base material layer 21, a first adhesive layer 22, a metal foil layer 23, a corrosion prevention treatment layer 24, a sealant adhesive layer 25, and a sealant layer 26 are sequentially laminated.

  The base material layer 21 imparts heat resistance to the exterior material 20 in a pressurization thermal fusion process, which will be described later when manufacturing the power storage device, and plays a role of suppressing the generation of pinholes that may occur during processing or distribution. It is a layer for. The first adhesive layer 22 is a layer that bonds the base material layer 21 and the metal foil layer 23 together. The corrosion prevention treatment layer 24 plays a role of suppressing the corrosion of the metal foil layer 23 due to the electrolytic solution or hydrofluoric acid generated by the reaction between the electrolytic solution and moisture. The sealant adhesive layer 25 is a layer that bonds the metal foil layer 23 on which the corrosion prevention treatment layer 24 is formed and the sealant layer 26.

  The base material layer 21, the first adhesive layer 22, the metal foil layer 23, the corrosion prevention treatment layer 24, the sealant adhesive layer 25 and the sealant layer 26 of the exterior material 20 are respectively the second base material layer 13 and the first base material layer 13 of the exterior material 10. The adhesive layer 12, the metal foil layer 15, the corrosion prevention treatment layer 16, the sealant adhesive layer 17, and the sealant layer 18 can be configured similarly.

[Method of manufacturing exterior material]
Next, the manufacturing method of the exterior material 10 is demonstrated. In addition, the manufacturing method of the exterior material 10 is not limited to the following method.

As a manufacturing method of the exterior material 10, the method which has following process S11-S14 is mentioned, for example.
Step S <b> 11: A step of forming the corrosion prevention treatment layer 16 on one surface of the metal foil layer 15.
Process S12: The process of bonding the 1st base material layer 11 and the 2nd base material layer 13 through the 1st contact bonding layer 12, and obtaining a laminated body.
Step S13: The other surface of the metal foil layer 15 (the surface opposite to the side on which the corrosion prevention treatment layer 16 is formed) and the second adhesive layer 14 are interposed between the second base material layer 13 side of the laminate. The process of bonding the surface.
Step S14: A step of forming a sealant layer 18 on the corrosion prevention treatment layer 16 via a sealant adhesive layer 17.

(Process S11)
In step S <b> 11, the corrosion prevention treatment layer 16 is formed on one surface of the metal foil layer 15 by, for example, applying a corrosion prevention treatment agent on one surface of the metal foil layer 15 and drying. Examples of the anti-corrosion treatment agent include the above-described anti-corrosion treatment agent for ceriazole treatment and the anti-corrosion treatment agent for chromate treatment. The coating method of the corrosion inhibitor is not particularly limited, and various methods such as gravure coating, reverse coating, roll coating, and bar coating can be adopted.

(Process S12)
In step S12, the second base material layer 13 is bonded to the first base material layer 11 by a technique such as dry lamination using an adhesive that forms the first adhesive layer 12. A laminate in which the one adhesive layer 12 and the second base material layer are laminated in this order is obtained. In the step (2-2), aging (curing) may be performed in the range of 40 ° C to 100 ° C in order to promote adhesion. The aging time is, for example, 3 to 10 days.

(Process S13)
In step S13, the other surface of the metal foil layer 15 (the surface opposite to the side on which the corrosion prevention treatment layer 16 is formed) and the adhesive for forming the second adhesive layer 14 are used by a technique such as dry lamination. The surface on the second base material layer 13 side of the laminate is bonded. In step S13, an aging (curing) treatment may be performed in the range of room temperature to 100 ° C. to promote adhesion. The aging time is, for example, 3 to 10 days.

(Step S14)
After step S13, corrosion of the laminated body in which the first base material layer 11, the first adhesive layer 12, the second base material layer 13, the second adhesive layer 14, the metal foil layer 15, and the corrosion prevention treatment layer 16 are laminated in this order. A sealant layer 18 is formed on the prevention treatment layer 16 via a sealant adhesive layer 17. The sealant layer 18 may be laminated by dry lamination, sandwich lamination, or the like, or may be laminated together with the sealant adhesive layer 17 by a coextrusion method. From the viewpoint of improving adhesiveness, the sealant layer 18 is preferably laminated by sandwich lamination, for example, or is preferably laminated together with the sealant adhesive layer 17 by a coextrusion method, and more preferably laminated by sandwich lamination.

  Furthermore, the manufacturing method of the exterior material 20 is demonstrated. In addition, the manufacturing method of the exterior material 20 is not limited to the following method.

As a manufacturing method of the exterior material 20, the method which has following process S11'-S13 'is mentioned, for example.
Step S11 ′: a step of forming a corrosion prevention treatment layer 24 on one surface of the metal foil layer 23.
Step S12 ′: a step of forming the base material layer 21 on the other surface of the metal foil layer 23 via the first adhesive layer 22.
Step S13 ′: a step of forming a sealant layer 26 on the corrosion prevention treatment layer 24 via a sealant adhesive layer 25.

  In step S <b> 11 ′, the corrosion prevention treatment layer 24 is formed on one surface of the metal foil layer 23 in the same manner as the metal foil layer 15 and the corrosion prevention treatment layer 16 in step S <b> 11. In step S <b> 12 ′, the base material layer 21 is formed on the other surface of the metal foil layer 23 via the first adhesive layer 22, similarly to the metal foil layer 15 in step S <b> 13 and the laminate. In step S <b> 13 ′, the sealant layer 26 is formed on the corrosion prevention treatment layer 24 in the same manner as the corrosion prevention treatment layer 16 and the sealant layer 18 in step S <b> 14.

[Power storage device]
Next, a power storage device including the exterior material 10 or the exterior material 20 as a container will be described. The power storage device includes a battery element 1 including an electrode, a lead 2 extending from the electrode, and a container that houses the battery element 1, and the container is formed from the power storage device exterior material 10 or the power storage device exterior material 20. The sealant layer 18 or the sealant layer 26 is formed inside. The container may be obtained by stacking two exterior materials with the sealant layer 18 or the sealant layer 26 facing each other, and heat-sealing the peripheral portions of the overlaid exterior material 10 or the exterior material 20, It may be obtained by folding and stacking one exterior material and similarly heat-sealing the periphery of the exterior material 10 or the exterior material 20. Examples of the power storage device include secondary batteries such as lithium ion batteries, nickel metal hydride batteries, and lead storage batteries, and electrochemical capacitors such as electric double layer capacitors.

  The lead 2 is sandwiched and sealed by the exterior material 10 or the exterior material 20 that forms a container with the sealant layer 18 or the sealant layer 26 inside. The lead 2 may be sandwiched between the exterior material 10 or the exterior material 20 via a tab sealant.

[Method for Manufacturing Power Storage Device]
Next, a method for manufacturing a power storage device using the exterior material 10 or the exterior material 20 described above will be described. Here, a case where the secondary battery 40 is manufactured using the embossed type exterior material 30 will be described as an example. FIG. 3 is a view showing the embossed type exterior member 30. 4A to 4D are perspective views illustrating a manufacturing process of a one-side molded battery using the exterior material 10 or the exterior material 20. The secondary battery 40 is a double-sided molded battery that is manufactured by bonding two exterior materials such as the embossed type exterior material 30 and bonding the exterior materials together while adjusting the alignment. Also good.

The secondary battery 40 that is a one-side molded battery can be manufactured, for example, by the following steps S21 to S25.
Step S21: a step of preparing the exterior material 10 or the exterior material 20, the battery element 1 including an electrode, and the lead 2 extending from the electrode.
Process S22: The process of forming the recessed part 32 for arrange | positioning the battery element 1 in the single side | surface of the exterior material 10 or the exterior material 20 (refer Fig.4 (a) and FIG.4 (b)).
Step S23: The battery element 1 is arranged in the molding processing area (recessed portion 32) of the embossed-type exterior member 30, and the embossed-type exterior member 30 is folded and overlapped so that the lid portion 34 covers the recessed portion 32, and extends from the battery element 1. A step of pressurizing and heat-bonding one side of the embossed type exterior member 30 so as to sandwich the lead 2 to be held (see FIGS. 4B and 4C).
Step S24: Leave one side other than the side sandwiching the lead 2 and pressurize and melt the other side, then inject the electrolyte from the remaining side and pressurize and heat-bond the remaining side in a vacuum state Step (see FIG. 4C).
Step S25: A step of cutting the end portion of the heat-bonded side other than the side sandwiching the lead 2 and bending it to the side of the molding area (recess 32) (see FIG. 4D).

(Process S21)
In step S21, the exterior member 10 or the exterior member 20, the battery element 1 including an electrode, and the lead 2 extending from the electrode are prepared. The exterior material 10 or the exterior material 20 is prepared based on the embodiment described above. There is no restriction | limiting in particular as the battery element 1 and the lead 2, The well-known battery element 1 and the lead 2 can be used.

(Step S22)
In step S <b> 22, a recess 32 for arranging the battery element 1 on the sealant layer 18 or sealant layer 26 side of the exterior material 10 or the exterior material 20 is formed. As a method for forming the concave portion 32, a molding process using a mold (deep drawing molding) may be mentioned. As a molding method, a female mold and a male mold arranged so as to have a gap larger than the thickness of the exterior material 10 or the exterior material 20 are used, and the male mold is used together with the exterior material 10 or the exterior material 20. There is a method of pushing into a female mold. By adjusting the pushing amount of the male mold, the depth (deep drawing amount) of the recess 32 can be adjusted to a desired amount. By forming the recess 32 in the exterior material 10 or the exterior material 20, an embossed-type exterior material 30 is obtained.

(Step S23)
In step S <b> 23, the battery element 1 including the positive electrode, the separator, the negative electrode, and the like is disposed in the molding processing area (recess 32) of the embossed type exterior material 30. Further, the lead 2 extending from the battery element 1 and bonded to the positive electrode and the negative electrode, respectively, is drawn out from the molding area (recess 32). Thereafter, the embossed type exterior member 30 is folded back at the approximate center in the longitudinal direction, and the sealant layer 18 or the sealant layer 26 is overlapped with each other so that one side sandwiching the lead 2 of the embossed type exterior member 30 is pressurized. Heat-sealed. The pressure heat fusion is controlled by three conditions of temperature, pressure, and time, and is appropriately set. The temperature of the pressure heat fusion is preferably equal to or higher than the temperature at which the sealant layer 18 or the sealant layer 26 is melted.

  The thickness of the sealant layer 18 or the sealant layer 26 before heat sealing is preferably 40% or more and 80% or less with respect to the thickness of the lead 2. When the thickness of the sealant layer 18 or the sealant layer 26 is equal to or greater than the lower limit value, the heat-sealing resin tends to sufficiently fill the end of the lead 2, and when the thickness is equal to or less than the upper limit value, the secondary battery 40. Thus, the thickness of the end portion of the exterior material 10 or the exterior material 20 can be moderately suppressed, and the amount of moisture entering from the end portion of the exterior material 10 or the exterior material 20 can be reduced.

(Process S24)
In step S24, one side other than the side sandwiching the lead 2 is left and the other side is subjected to pressure heat fusion. Thereafter, an electrolytic solution is injected from the remaining side, and the remaining side is pressurized and heat-sealed in a vacuum state. The conditions for the pressure heat fusion are the same as in step S23.

(Step S25)
The edge portion of the peripheral pressure heat fusion side other than the side sandwiching the lead 2 is cut, and the sealant layer 18 or the sealant layer 26 protruding from the end portion is removed. Then, the secondary battery 40 is obtained by folding the peripheral pressure heat-sealed portion toward the molding area 32 and forming the folded portion 42.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the scope of the present invention is not limited to these examples.

[Evaluation method]
(Warpage after molding)
The exterior materials obtained in the examples and comparative examples were cut into a shape of 120 mm × 260 mm, and placed in the molding apparatus so that the sealant layer faced upward. The molding depth of the molding apparatus was set to 3 mm, and cold molding was performed in an environment of room temperature 23 ° C. dew point temperature −35 ° C. Use a punch die that has a rectangular cross section of 70 mm x 80 mm, a punch radius (RP) of 0.75 mm on the bottom, and a punch corner radius (RCP) of 1.5 mm on the side did. Further, a die having a 0.75 mm diradius (RD) on the upper surface of the opening was used. The clearance between the punch mold and the die mold was 0.20 mm. The molding area was the approximate center of the half surface divided by the approximate center in the longitudinal direction of the cut exterior material. That is, the molding area was arranged so that both ends of the molding area were positioned at 25 mm from both ends in the short direction of the cut exterior material.

  The exterior material after molding is left on a horizontal table for 60 minutes in an environment with a room temperature of 23 ° C and a dew point of -35 ° C so that the base material layer side faces upward, and the short direction of the unmolded area side The maximum value of the distance from the center of the side of the side was measured, and the measured value was taken as the amount of warpage. However, when warping at an angle of 90 degrees or more, the amount of warpage cannot be measured, and thus measurement is not possible.

(Molding depth)
The exterior materials obtained in the examples and comparative examples were cut into a 150 mm × 190 mm shape and placed in the molding apparatus so that the sealant layer faced upward. The molding depth of the molding apparatus was set to 1 to 10 mm every 1 mm, and cold molding was performed in an environment of room temperature 23 ° C. dew point temperature −35 ° C., and the moldability at each molding depth was evaluated according to the following criteria. The punch mold has a rectangular cross section of 100 mm × 150 mm, has a punch radius (RP) of 0.75 mm on the bottom surface, and a punch corner radius (RCP) of 1.5 mm on the side surface. It was used. Further, a die having a 0.75 mm diradius (RD) on the upper surface of the opening was used. Evaluation criteria were performed according to the following.
A: Deep drawing with a molding depth of 6 mm or more is possible without breaking or cracking.
B: Deep drawing with a molding depth of 4 mm or more and less than 6 mm is possible without causing breakage or cracks.
C: Breaking or cracking occurs in deep drawing with a molding depth of less than 4 mm.

[Material used for exterior material 10]
The first base material layer 11, the first adhesive layer 12, the second base material layer 13, the second adhesive layer 14, the metal foil layer 15, the corrosion prevention treatment layer 16, and the sealant of the exterior material 10 of the examples and comparative examples. The materials used to form the adhesive layer 17 and the sealant layer 18 are shown below.

(First base material layer 11)
Base material A-1: Sequential biaxially stretched PET film (thickness: 12 μm)

(First adhesive layer 12, second adhesive layer 14)
Adhesive B-1: Aliphatic polyester polyol (main agent, Takelac A-505 (manufactured by Mitsui Chemicals)) 92 parts by mass, hexamethylene diisocyanate (curing agent, Duranate TPA-100, manufactured by Asahi Kasei Chemicals) 8 parts by mass Adhesive B -2: 90 parts by mass of maleic anhydride-modified polyolefin resin (main agent, Sumifit CK1D (manufactured by Sumika Chemtex)), 10 parts by mass of adhesive B for hexamethylene diisocyanate (curing agent, Duranate TPA-100, manufactured by Asahi Kasei Chemicals) -3: 87 parts by mass of aromatic polyester polyol (main agent, Takelac A-977 (manufactured by Mitsui Chemicals)), 13 parts by mass of tolylene diisocyanate (curing agent, coronate L-55E (manufactured by Nippon Polyurethane Industry))

(Second base material layer 13)
Substrate C-1: Sequential biaxially stretched Ny film (thickness: 15 μm)

(Metal foil layer 15)
Metal foil D-1: Soft aluminum foil 8079 material (manufactured by Toyo Aluminum Co., Ltd., thickness: 40 μm)

(Corrosion prevention treatment layer 16)
Treatment agent E-1: Treatment agent for coating type ceriazole treatment mainly composed of cerium oxide, phosphoric acid, and acrylic resin.

(Sealant adhesive layer 17)
Adhesive resin F-1: Polypropylene resin graft-modified with maleic anhydride (trade name “Admer”, manufactured by Mitsui Chemicals)

(Sealant layer 18)
Film G-1: A film obtained by corona-treating the surface to be the inner surface of an unstretched polypropylene film (thickness: 60 μm).

[Preparation of exterior material 10]
Example 1
The treatment agent E-1 was applied to one surface of the metal foil D-1 and dried to form a corrosion prevention treatment layer 16 on the metal foil layer 15. Next, the base material C-1 is bonded to the base material A-1 through the adhesive B-1 by the dry laminating method, and the second base material is bonded to the first base material layer 11 through the first adhesive layer 12. The laminated body in which the base material layer 13 was formed was obtained. Next, the base material C-1 side of the laminate is bonded to the opposite surface of the metal foil layer 15 to the anticorrosion treatment layer 16 via the adhesive B-3 by the dry laminating method. A laminated body in which the layer 11, the first adhesive layer 12, the second base material layer 13, the second adhesive layer 14, the metal foil layer 15, and the corrosion prevention treatment layer 16 were laminated in this order was obtained. Thereafter, the obtained laminate was aged at 60 ° C. for 6 days. Next, by extruding the adhesive resin F-1 to the corrosion prevention treatment layer 16 side of the laminate after aging with an extrusion device, and further laminating the film G-1 on the adhesive resin F-1, A sealant layer 18 was formed via a sealant adhesive layer 17 on the anti-corrosion treatment layer 16 of the laminate after aging. Then, the exterior material 10 was produced by heat-pressing the obtained laminated body at 190 degreeC. The thickness of the first adhesive layer 12 after lamination was 5 μm, the thickness of the second adhesive layer 14 after lamination was 5 μm, and the thickness of the sealant adhesive layer 17 after lamination was 25 μm.

(Examples 2-3 and Comparative Example 1)
The materials used to form the first base material layer 11, the first adhesive layer 12, the second base material layer 13 and the second adhesive layer 14 of the exterior material 10 have been changed to the materials shown in Table 1. Except for the above, in the same manner as Example 1, the exterior materials 10 of Examples 2 to 3 and Comparative Example 1 were obtained. Table 1 shows the evaluation results of warpage and molding depth after molding of the exterior material 10 obtained in Examples 1 to 3 and Comparative Example 1.

[Material used for exterior material 20]
Next, in order to form the base material layer 21, the first adhesive layer 22, the metal foil layer 23, the corrosion prevention treatment layer 24, the sealant adhesive layer 25, and the sealant layer 26 of the exterior material 20 of the example and the comparative example. The materials used for are shown below.

(Base material layer 21)
Substrate C-2: Sequential biaxially stretched Ny film (thickness: 25 μm)

(First adhesive layer 22)
Adhesive B-1: Aliphatic polyester polyol (main agent, Takelac A505 (manufactured by Mitsui Chemicals)) 92 parts by mass, hexamethylene diisocyanate (curing agent, Duranate TPA-100 (manufactured by Asahi Kasei Chemicals)) 8 parts by mass adhesive B-2 : Maleic anhydride-modified polyolefin resin (main agent, Sumifit CK1D, (manufactured by Sumika Chemtex)) 92 parts by mass, hexamethylene diisocyanate (curing agent, Duranate TPA-100 (manufactured by Asahi Kasei Chemicals)) 8 parts by mass Adhesive B- 3: 87 parts by mass of aromatic polyester polyol (main agent, Takelac A505 (manufactured by Mitsui Chemicals)), 13 parts by mass of tolylene diisocyanate (curing agent, Coronate L-55E (manufactured by Nippon Polyurethane Industry)) Adhesive B-4: anhydrous Maleic acid-modified styrene-polyolefin resin (mainly , Alastor 700S (manufactured by Arakawa Chemical Industries)) 90 parts by mass, hexamethylene diisocyanate (curing agent, Duranate TPA-100 (manufactured by Asahi Kasei Chemicals)) 10 parts by mass Adhesive B-5: Aliphatic polyester polyol (main agent, Takelac A505 ( (Mitsui Chemicals)) 85 parts by mass, tolylene diisocyanate (curing agent, Coronate L-55E (manufactured by Nippon Polyurethane Industry)) 15 parts by mass Adhesive B-6: Aliphatic polyester polyol (main agent, Takelac A505 (made by Mitsui Chemicals)) ) 83 parts by mass, 17 parts by mass of diphenylmethane diisocyanate (curing agent) Adhesive B-7: 87 parts by mass of aromatic polyether polyol (main agent, Takelac A950 (manufactured by Mitsui Chemicals)), hexamethylene diisocyanate (curing agent, Duranate TPA) -100 (Asahi Kasei Chemi Luz Ltd.)) 13 parts by weight

(Metal foil layer 23)
Metal foil D-1: Soft aluminum foil 8079 material (manufactured by Toyo Aluminum Co., Ltd., thickness: 40 μm)

(Corrosion prevention treatment layer 24)
Treatment agent E-1: Treatment agent for coating type ceriazole treatment mainly composed of cerium oxide, phosphoric acid, and acrylic resin.

(Sealant adhesive layer 25)
Adhesive resin F-1: Polypropylene resin graft-modified with maleic anhydride (trade name “Admer”, manufactured by Mitsui Chemicals)

(Sealant layer 26)
Film G-1: A film obtained by corona-treating the surface to be the inner surface of an unstretched polypropylene film (thickness: 60 μm).

[Preparation of exterior material 20]
Example 4
The treatment agent E-1 was applied to one surface of the metal foil D-1 and dried to form a corrosion prevention treatment layer 24 on the metal foil layer 23. Next, the base material layer 21 is bonded to the opposite surface of the corrosion prevention treatment layer 24 in the metal foil layer 23 by the dry laminating method through the adhesive B-1, and the first adhesive layer is formed on the base material layer 21. The laminated body in which the metal foil layer 23 was formed through 22 and the corrosion prevention treatment layer 24 was formed on the metal foil layer 23 was obtained. Thereafter, the obtained laminate was aged at 60 ° C. for 6 days. Next, by extruding the adhesive resin F-1 to the corrosion prevention treatment layer 24 side of the laminate after aging with an extrusion device, and further laminating the film G-1 on the adhesive resin F-1, A sealant layer 26 was formed on the corrosion prevention layer 24 of the laminated body after aging via a sealant adhesive layer 25. Then, the exterior material 20 was produced by heat-pressing the obtained laminated body at 190 degreeC. In addition, the thickness of the 1st contact bonding layer 22 after lamination | stacking was 5 micrometers, and the thickness of the sealant contact bonding layer 25 after lamination | stacking was 25 micrometers.

(Example 5 and Comparative Examples 2 to 6)
Example 5 and Example 5 except that the materials used to form the base material layer 21 and the first adhesive layer 22 of the exterior material 20 were changed to the materials shown in Table 2. The exterior material 20 of Comparative Examples 2-6 was obtained. Table 2 shows the evaluation results of warpage and molding depth after molding of the packaging material 10 obtained in Examples 4 to 5 and Comparative Examples 2 to 6.

  As shown in Tables 1 and 2, in the exterior materials of Examples 1 to 5 using an aliphatic polyurethane resin for the first adhesive layer, the warpage amount after molding showed a small value of 20 mm or less, and was excellent. The molding depth is shown. Moreover, in Examples 1-2 which used the aromatic polyurethane resin for the 2nd contact bonding layer in the cladding | exterior_material 10, the further outstanding shaping | molding depth was shown, reducing the curvature amount after shaping | molding.

  On the other hand, in Comparative Examples 1 to 6 using an aromatic polyurethane resin for the first adhesive layer, the elastic deformation part at the time of molding cannot be reduced, the amount of warping after the molding becomes large, and an angle of 90 degrees or more The amount of warpage could not be measured because warpage occurred.

DESCRIPTION OF SYMBOLS 1 ... Battery element, 2 ... Lead | read | reed 10,20 ... Exterior material (exterior material for electrical storage devices), 11 ... 1st base material layer, 12 ... 1st adhesive layer, 13 ... 2nd base material layer, 14 ... 2nd Adhesive layer, 15 ... metal foil layer, 16 ... corrosion prevention treatment layer, 17 ... sealant adhesive layer, 18 ... sealant layer, 21 ... base material layer, 22 ... first adhesive layer, 23 ... metal foil layer, 24 ... corrosion prevention Treatment layer, 25 ... Sealant adhesive layer, 26 ... Sealant layer, 30 ... Embossed type exterior material, 32 ... Molding process area (recess), 34 ... Lid, 40 ... Secondary battery.

Claims (9)

A first base material layer, a second base material layer formed on one surface of the first base material layer via a first adhesive layer, and the first base material layer of the second base material layer, Comprises a metal foil layer formed on the opposite surface via a second adhesive layer, and a sealant layer disposed on the surface of the metal foil layer opposite to the second base material layer,
The outer packaging material for a power storage device, wherein the first adhesive layer includes an aliphatic polyurethane resin obtained by reacting an aliphatic polymer having two or more hydroxyl groups or two or more acid anhydride groups with an aliphatic polyisocyanate. .   The power storage device exterior material according to claim 1, wherein the second adhesive layer includes an aromatic polyurethane resin.   The power storage device exterior material according to claim 1 or 2, wherein the first base material layer is a stretched polyester film and the second base material layer is a stretched polyamide film.   The thickness of said 1st base material layer is 4 micrometers or more and 20 micrometers or less, For the electrical storage apparatus as described in any one of Claims 1-3 whose thickness of said 2nd base material layer is 5 micrometers or more and 30 micrometers or less. Exterior material. A base material layer, a metal foil layer formed on one surface of the base material layer via a first adhesive layer, and a sealant disposed on the surface of the metal foil layer opposite to the base material layer With layers,
The base material layer is a stretched polyamide film;
It said first adhesive layer, seen contains two or more hydroxyl groups or aliphatic polyurethane resin obtained by reacting an aliphatic polymer and aliphatic polyisocyanate having two or more acid anhydride groups,
An exterior material for a power storage device, wherein the aliphatic polymer is an aliphatic polyester having two or more hydroxyl groups or two or more acid anhydride groups . A base material layer, a metal foil layer formed on one surface of the base material layer via a first adhesive layer, and a sealant disposed on the surface of the metal foil layer opposite to the base material layer With layers,
The base material layer is a stretched polyamide film;
The first adhesive layer includes an aliphatic polyurethane resin obtained by reacting an aliphatic polymer having two or more hydroxyl groups or two or more acid anhydride groups with an aliphatic polyisocyanate,
The aliphatic polymer is an aliphatic polymer having two or more hydroxyl groups selected from an aliphatic polyester polyol, an aliphatic polyether polyol, and an aliphatic polyol whose main chain is composed of a carbon-carbon bond, or two A packaging material for a power storage device, which is an aliphatic polymer having the above acid anhydride group.   The power storage device exterior material according to claim 5 or 6, wherein a thickness of the base material layer is 5 µm or more and 30 µm or less.   The exterior material for a power storage device according to any one of claims 1 to 7, wherein the aliphatic polyurethane resin is obtained by reacting an aliphatic polymer having two or more hydroxyl groups with an aliphatic polyisocyanate. . A battery element including an electrode, a lead extending from the electrode, and a container containing the battery element,
The said container is an electrical storage apparatus formed from the exterior material for electrical storage apparatuses as described in any one of Claims 1-8 so that the said sealant layer may become an inner side.

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