JP2019194952A - Power storage device exterior material and power storage device - Google Patents

Abstract

To provide a power storage device exterior material that has excellent scratch resistance, excellent moldability, and hardly undergoes discoloration due to molding.SOLUTION: A power storage device exterior material includes a heat-resistant resin layer 2 as an outer layer, a heat-fusible resin layer 3 as an inner layer, and a metal foil layer 4 disposed between these two layers, a protective resin layer 7 is laminated on the outer side of the heat-resistant resin layer 2, the protective resin layer 7 includes a resin and a spacer agent that is not compatible with the resin, and a part of the spacer agent protrudes outward from the surface of the protective resin layer 7.SELECTED DRAWING: Figure 1

Description

  The present invention is for batteries and capacitors used for portable devices such as smartphones and tablets, hybrid vehicles, electric vehicles, wind power generation, solar power generation, storage devices such as batteries and capacitors used for storage of night electricity. The present invention relates to an exterior material and an electricity storage device that is exteriorized with the exterior material.

  In recent years, as mobile electrical devices such as smartphones and tablet terminals have become thinner and lighter, power storage devices such as lithium-ion secondary batteries, lithium-polymer secondary batteries, lithium-ion capacitors, and electric double-layer capacitors that are installed in these devices have been reduced. As an exterior material, instead of a conventional metal can, a heat resistant resin layer (base material layer) / outer adhesive layer / metal foil layer / inner adhesive layer / heat-sealable resin layer (inner sealant layer) is used. A laminate is used (see Patent Document 1). In addition, a power source for an electric vehicle, a large-scale power source for power storage, a capacitor, and the like are increasingly covered with a laminate (exterior material) having the above-described configuration. By performing overhang molding or deep drawing molding on the exterior material, the exterior material is molded into a three-dimensional shape such as a substantially rectangular parallelepiped shape. By forming into such a three-dimensional shape, an accommodation space for accommodating the electricity storage device main body can be secured.

  In addition, a configuration in which a mat varnish layer is provided outside the base material layer in order to protect the exterior material and improve the moldability has been proposed (see Patent Document 2). Examples of the mat varnish layer include cellulose-based, polyamide-based, vinyl chloride-based, modified polyolefin-based, rubber-based, acrylic-based, urethane-based olefin-based, alkyd-based synthetic resins, silica-based, kaolin-based, etc. An example is a mat varnish to which an appropriate amount of an inorganic material matting agent is added (see Patent Document 2).

JP 2003-288865 A JP 2011-54563 A

  By the way, when the exterior case is obtained by performing overmolding or the like on the conventional exterior material, there is a problem that discoloration occurs on the surface of the exterior case.

  In addition, the conventional exterior material has a problem in that appearance defects such as scratches are likely to occur due to abrasion during transportation.

  The present invention has been made in view of such a technical background, and has an exterior material for an electricity storage device and an exterior material that are excellent in scratch resistance, excellent in moldability, and hardly discolored by molding. An object is to provide a packaged electricity storage device.

  In order to achieve the above object, the present invention provides the following means.

[1] A power storage device exterior material including a heat-resistant resin layer as an outer layer, a heat-fusible resin layer as an inner layer, and a metal foil layer disposed between both layers,
A protective resin layer is laminated on the outer side of the heat resistant resin layer,
The protective resin layer contains a resin and a spacer agent that is not compatible with the resin,
A part of the spacer agent protrudes outward from the surface of the protective resin layer.

  [2] The electricity storage device exterior material according to item 1, wherein the spacer agent is contained in the protective resin layer in the form of an aggregate of a plurality of spacer agents.

  [3] The packaging material for an electricity storage device according to item 2 above, wherein each spacer agent constituting the aggregate has an average particle diameter of 1 μm to 20 μm.

  [4] The exterior packaging material for an electricity storage device according to the above item 2 or 3, wherein an average major axis in a plan view of the spacer agent aggregate in the protective resin layer is in the range of 10 μm to 120 μm.

  [5] The exterior material for an electricity storage device according to any one of the above items 2 to 4, wherein the protruding height of the spacer agent aggregate protruding outward from the surface of the protective resin layer is 1 μm or more.

  [6] The planar view area of the protruding portion having a protruding height of 1 μm or more from which the spacer agent aggregate protrudes outward from the surface of the protective resin layer is 4 of the entire planar view area of the protective resin layer. 6. The exterior device for an electricity storage device according to any one of 2 to 5 above, which is% to 20%.

  [7] The protrusion height at which the spacer agent aggregate protrudes outward from the surface of the protective resin layer is 0.5 μm to 10 μm, and the spacer agent aggregate in the protective resin layer in plan view 5. The exterior packaging material for an electricity storage device according to any one of items 2 to 4, wherein the average major axis is in the range of 10 μm to 120 μm.

  [8] The exterior material for an electricity storage device according to any one of items 1 to 7, wherein the spacer agent is one or more spacer agents selected from the group consisting of waxes and polymer powders.

  [9] The exterior material for an electricity storage device according to any one of 1 to 8 above, wherein the spacer agent has a melting point of 90 ° C to 350 ° C.

  [10] The exterior material for an electricity storage device according to any one of items 1 to 9, wherein the content of the spacer agent in the protective resin layer is 2% by mass to 20% by mass.

  [11] The exterior material for an electricity storage device according to any one of 1 to 10 above, wherein the resin is a reaction product resin of a polyol and a polyisocyanate.

  [12] The aforementioned protective resin layer further contains a matting agent composed of fine particles, and the average major axis of the matting agent in the protective resin layer in a plan view of the protective resin layer is in the range of 0.3 μm to 7 μm. The exterior material for electrical storage devices of any one of 1-11.

  [13] An exterior case for an electricity storage device comprising a molded body of the exterior material for an electricity storage device according to any one of 1 to 12 above.

[14] An electricity storage device body,
The exterior member for an electricity storage device according to any one of items 1 to 12 and / or the exterior member comprising the exterior case for an energy storage device according to item 13 above,
The electricity storage device, wherein the electricity storage device body is covered with the exterior member.

  In the invention of [1], the protective resin layer provided on the outer side of the heat-resistant resin layer contains a resin and a spacer agent that is not compatible with the resin. Part) protrudes outward from the surface of the protective resin layer, so that the exterior material for an electricity storage device of the present invention is excellent in scratch resistance. Further, when molding the exterior material for an electricity storage device of the present invention, a part of the spacer agent (including aggregates) protrudes outward from the surface of the protective resin layer, so that the molding surface of the molding die Since direct contact with the protective resin layer is prevented, the moldability is excellent and discoloration hardly occurs in the molded exterior material.

  In the invention of [2], since the spacer agent is contained in the protective resin layer in the form of an aggregate of a plurality of spacer agents, the molding surface of the mold and the spacer agent aggregate (protruding portion of the aggregate) When they come into contact with each other, the agglomerates are liable to collapse and the slipperiness is good, and the moldability can be further improved.

  In the invention of [3], since the average particle diameter of each spacer agent constituting the aggregate is 5 μm to 10 μm, when the molding surface of the mold comes into contact with the aggregate, the aggregate is more easily broken and slippery. It can be improved.

  In the invention of [4], since the average major axis in the plan view of the spacer agent aggregate in the protective resin layer is in the range of 30 μm to 120 μm, the molding surface of the mold and the protective resin layer are in direct contact with each other. It can be sufficiently prevented.

  In the invention of [5], since the protrusion height of the spacer agent aggregate protruding outward from the surface of the protective resin layer is 1 μm or more, the scratch resistance of the exterior material can be further improved, Discoloration due to molding in the molded exterior material can be further prevented.

  In the invention of [6], direct contact between the molding surface of the mold and the protective resin layer can be more sufficiently prevented.

  In the invention of [7], direct contact between the molding surface of the mold and the protective resin layer can be more sufficiently prevented.

  In the invention of [8], since the specific spacer agent is used, the dispersibility of the spacer agent (including spacer agent aggregates) in the protective resin layer is good, and it is uniformly removed from the surface of the protective resin layer. A side protrusion can be formed, and excellent scratch resistance and excellent moldability can be stably secured.

  In the invention of [9], since the melting point of the spacer agent is 90 ° C. to 180 ° C., the protective resin layer can be formed without melting the spacer agent during drying during the formation of the protective resin layer, and the battery element is The shape of the spacer agent can be maintained when heat sealing with the exterior material.

  In the invention of [10], the content of the spacer agent in the protective resin layer is 2% by mass to 20% by mass, and when it is 2% by mass or more, excellent scratch resistance and excellent moldability can be sufficiently secured. At the same time, the protective function of the protective resin layer can be sufficiently exhibited by being 20% by mass or less.

  In the invention of [11], the chemical resistance (solvent resistance, acid resistance, etc.) of the exterior material can be further improved.

  In the invention of [12], the protective resin layer further contains a matting agent composed of fine particles, and the average major axis of the matting agent in the protective resin layer in a plan view of the protective resin layer is in the range of 0.3 μm to 7 μm. Therefore, the mat-like appearance can be easily adjusted, and the desired appearance can be surely expressed.

  According to the invention of [13], it is possible to provide an outer case for an electricity storage device that has excellent scratch resistance and is well-formed and has no discoloration.

  In the invention of [14], an electricity storage device covered with an exterior member having excellent scratch resistance can be provided.

It is sectional drawing which shows one Embodiment of the exterior material for electrical storage devices which concerns on this invention. It is sectional drawing which expands and schematically shows a part of outer layer and protective layer. It is sectional drawing which shows one Embodiment of the electrical storage device which concerns on this invention.

  One embodiment of an exterior material 1 for an electricity storage device according to the present invention is shown in FIG. The power storage device exterior material 1 includes a heat-resistant resin layer (outer layer) 2 laminated and integrated on one surface (upper surface) of a metal foil layer 4 with a first adhesive layer 5 interposed therebetween. A heat-fusible resin layer (inner layer) 3 is laminated and integrated on the other surface (lower surface) of the layer 4 via a second adhesive layer 6, and on the outer side of the heat-resistant resin layer 2 (the heat-resistant resin). The protective resin layer 7 is laminated on the side of the layer 2 opposite to the metal foil layer 4 side. In the present embodiment, the protective resin layer 7 is directly laminated on the outer surface of the heat resistant resin layer 2 (on the surface opposite to the metal foil layer 4 side of the heat resistant resin layer 2) (FIG. 1). In the present embodiment, the protective resin layer 7 is laminated by applying a resin composition directly to the outer surface of the heat resistant resin layer 2 by a gravure coating method.

  The heat-resistant resin layer (outer layer) 2 is a member mainly responsible for ensuring good moldability as the exterior material 1, that is, plays a role of preventing breakage due to necking of the metal foil during molding. is there.

  As the heat-resistant resin constituting the heat-resistant resin layer (outer layer) 2, a heat-resistant resin that does not melt at the heat sealing temperature when heat-sealing the power storage device exterior material 1 is used. As the heat-resistant resin, it is preferable to use a heat-resistant resin having a melting point higher by 10 ° C. or more than the melting point of the resin constituting the heat-fusible resin layer 3, and the melting point of the resin constituting the heat-fusible resin layer 3 It is particularly preferable to use a heat resistant resin having a melting point higher than 20 ° C.

  The heat-resistant resin layer (outer layer) 2 is not particularly limited, and examples thereof include a stretched polyamide film such as a stretched nylon film and a stretched polyester film. Among them, the heat-resistant resin stretched film layer 2 includes a biaxially stretched polyamide film such as a biaxially stretched nylon film, a biaxially stretched polybutylene terephthalate (PBT) film, a biaxially stretched polyethylene terephthalate (PET) film, or a biaxially stretched film. It is particularly preferable to use a polyethylene naphthalate (PEN) film. Moreover, as the heat resistant resin stretched film layer 2, it is preferable to use a heat resistant resin biaxially stretched film stretched by a simultaneous biaxial stretching method. Although it does not specifically limit as said nylon, For example, 6 nylon, 6, 6 nylon, MXD nylon etc. are mentioned. The heat-resistant resin layer 2 may be formed as a single layer (single stretched film), or a multilayer (stretched PET film / stretched nylon film) made of, for example, a stretched polyester film / stretched polyamide film. Etc.).

  The heat resistant resin layer (outer layer) 2 may be a resin layer formed by applying a heat resistant resin.

  The heat-resistant resin layer 2 preferably has a thickness of 12 μm to 50 μm. When using a polyester resin, the thickness is preferably 12 μm to 50 μm, and when using a nylon resin, the thickness is preferably 15 μm to 50 μm. By setting it above the preferred lower limit value, it is possible to ensure sufficient strength as the exterior material 1, and by setting it below the preferred upper limit value, it is possible to reduce the stress at the time of stretch molding or draw molding and improve the moldability. be able to.

  In the present invention, a protective resin layer 7 needs to be laminated on the outside of the heat resistant resin layer 2 (on the side opposite to the metal foil layer 4 side in the heat resistant resin layer 2). The protective resin layer 7 contains a resin and a spacer agent 8 that is not compatible with the resin, and a part of the spacer agent 8 protrudes outward from the surface of the protective resin layer 7. It has a configuration (see FIG. 2).

  In this embodiment, the spacer agent is dispersed and contained in the protective resin layer 7 in the form of an aggregate 8 of a plurality of spacer agents (see FIG. 2). The average particle diameter of each spacer agent constituting the aggregate is preferably 1 μm to 20 μm, and particularly preferably 5 μm to 10 μm. Therefore, the major axis of the spacer agent aggregate 8 in the protective resin layer 7 is preferably in the range of 10 μm to 120 μm. Among these, the major axis of the spacer agent aggregate 8 in the protective resin layer 7 is more preferably in the range of 40 μm to 70 μm, and particularly preferably in the range of 50 μm to 60 μm.

  The spacer agent 8 or the spacer agent aggregate 8 preferably has a protruding height H of 1 μm or more protruding outward from the surface of the protective resin layer 7 (see FIG. 2). When the protrusion height H is 1 μm or more, the scratch resistance of the exterior material 1 can be further improved. When the exterior material 1 is molded, the molding surface of the molding die and the protective resin layer 7 are provided. Since direct contact is prevented, the moldability is excellent and discoloration hardly occurs in the molded exterior material. Among these, the protrusion height H is more preferably in the range of 1.5 μm to 10.0 μm.

  Furthermore, the planar view area of the protruding portion where the protruding height at which the spacer agent 8 or / and the spacer agent aggregate 8 protrude outward from the surface of the protective resin layer 7 is 1 μm or more is the protective resin layer. It is preferably 4% to 20%, more preferably 6% to 15%, and particularly preferably 5% to 10% of the entire plane view area of 7.

  Although it does not specifically limit as resin which comprises the said protective resin layer 7, It is preferable to use the reaction product resin of a polyol and polyisocyanate. Although it does not specifically limit as said polyol, For example, a polyester polyol, a polyurethane polyol, a polyether polyol etc. are mentioned. The weight average molecular weight (Mw) of the polyol is preferably 3000 to 50000.

  The polyisocyanate is not particularly limited, and examples thereof include tolylene diisocyanate (TDI), hexamethylene diisocyanate (HMDI), TDI trimethylolpropane adduct, HMDI trimethylolpropane adduct, and the like. . Among these, as the polyisocyanate, it is preferable to use a trimethylolpropane adduct of TDI, a trimethylolpropane adduct of HMDI, or a “mixture of a trimethylolpropane adduct of TDI and a trimethylolpropane adduct of HMDI”.

  The spacer agent 8 is not particularly limited, but it is preferable to use one or more spacer agents selected from the group consisting of waxes and polymer powders. The waxes are not particularly limited, and examples thereof include paraffin wax, microcrystalline wax, hydrocarbon wax, and low molecular weight polyethylene wax. The polymer powder is not particularly limited, and examples thereof include ultra high molecular weight polyethylene powder, polyethylene powder, low molecular weight polyethylene powder, polypropylene powder, and low molecular weight polypropylene powder.

  The weight average molecular weight of the spacer agent 8 (when there is no molecular weight distribution, simply “molecular weight”) is preferably 100 to 6,000,000, more preferably 1000 to 8000, A range of ˜6000 is particularly preferred.

  The melting point of the spacer agent 8 is preferably 50 ° C to 350 ° C, more preferably 50 ° C to 180 ° C, and particularly preferably 90 ° C to 160 ° C.

Density of the spacer material 8 is preferably a ^{0.85g / cm 3 ~3.0g / cm 3} , and more preferably ^{0.88g / cm 3 ~2.3g / cm 3} .

  The content of the spacer agent in the protective resin layer 7 is preferably 2% by mass to 20% by mass. When it is 2% by mass or more, excellent scratch resistance and excellent moldability can be sufficiently ensured, and when it is 20% by mass or less, the protective function of the protective resin layer can be sufficiently exhibited. Especially, it is preferable that the content rate of the spacer agent in the said protective resin layer 7 is 5 mass%-15 mass%. Moreover, it is preferable that the content rate of the said resin in the said protective resin layer 7 is 60 mass%-98 mass%.

  The protective resin layer 7 may further contain a matting agent made of fine particles. In this case, it is preferable that the average value of the major axis of the matting agent in the protective resin layer 7 in a plan view of the protective resin layer 7 is in a range of 0.3 μm to 7 μm. The matting agent has an irregular shape on the surface of the protective resin layer 7 and diffuses light, thereby reducing the glossiness of the surface of the protective resin layer 7 and forming finely textured appearance. It is. The matting agent is not particularly limited, and examples thereof include inorganic fine particles (eg, barium sulfate fine particles, silica fine particles), resin beads (eg, acrylic resin beads, styrene resin beads). The average particle size of the matting agent is particularly preferably in the range of 0.5 μm to 5 μm. When barium sulfate fine particles are used as the matting agent, it is preferable to use barium sulfate fine particles having an average particle diameter of 0.3 μm to 3 μm. When acrylic resin beads are used as the matting agent, it is preferable to use acrylic resin beads having an average particle diameter of 3 μm to 5 μm.

  The thickness of the protective resin layer 7 (thickness after drying; excluding the protruding portion of the spacer agent) is preferably 0.5 μm to 10 μm.

  The method for forming the protective resin layer 7 is not particularly limited. For example, an aqueous emulsion (water-based emulsion) containing the resin and the spacer agent 8 is applied to the surface of the heat resistant resin layer 2 and dried. By doing so, the protective resin layer 7 can be formed. The coating method is not particularly limited, and examples thereof include a spray coating method, a gravure roll coating method, a reverse roll coating method, and a lip coating method.

  The heat-fusible resin layer (inner layer) 3 has excellent chemical resistance against highly corrosive electrolytes used in lithium ion secondary batteries and the like, and heat sealability on the exterior material. It plays the role of granting.

  The heat-fusible resin layer 3 is not particularly limited, but is preferably a thermoplastic resin unstretched film layer. The thermoplastic resin unstretched film layer 3 is not particularly limited, but is at least one thermoplastic selected from the group consisting of polyethylene, polypropylene, olefin copolymers, acid-modified products thereof, and ionomers. It is preferably composed of an unstretched film made of a resin.

  The thickness of the heat-fusible resin layer 3 is preferably set to 20 μm to 80 μm. When the thickness is 20 μm or more, pinholes can be sufficiently prevented from being generated, and by setting the thickness to 80 μm or less, the amount of resin used can be reduced, and the cost can be reduced. Especially, it is especially preferable that the thickness of the heat-fusible resin layer 3 is set to 30 μm to 50 μm. The heat-fusible resin layer 3 may be a single layer or a multilayer.

  A lubricant is usually added to the heat-fusible resin layer 3. The moldability at the time of molding can be improved by adding the lubricant. The content of the lubricant in the heat-fusible resin layer 3 is preferably set in the range of 200 ppm to 5000 ppm.

  The lubricant is not particularly limited, and examples thereof include saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, and aromatic bisamides. Can be mentioned.

  The metal foil layer 4 plays a role of imparting a gas barrier property to the exterior material 1 to prevent entry of oxygen and moisture. Although it does not specifically limit as said metal foil layer 4, For example, aluminum foil, copper foil, etc. are mentioned, Aluminum foil is generally used. The thickness of the metal foil layer 4 is preferably 20 μm to 100 μm. When it is 20 μm or more, it can prevent the occurrence of pinholes during rolling when manufacturing a metal foil, and when it is 100 μm or less, it can reduce the stress at the time of stretch forming or draw forming and improve the formability. it can.

The metal foil layer 4 is preferably subjected to a chemical conversion treatment on at least the inner surface 4a (surface on the second adhesive layer 6 side). By such chemical conversion treatment, corrosion of the surface of the metal foil due to the contents (battery electrolyte, food, medicine, etc.) can be sufficiently prevented. For example, the metal foil is subjected to chemical conversion treatment by the following treatment. That is, for example, on the surface of the metal foil that has been degreased,
1) Aqueous solution comprising a mixture of phosphoric acid, chromic acid and fluoride metal salt 2) Aqueous solution comprising a mixture of phosphoric acid, chromic acid, fluoride metal salt and non-metal salt 3) Acrylic resin and / or phenolic resin Then, a chemical conversion treatment is performed by applying one of an aqueous solution composed of a mixture of phosphoric acid, chromic acid, and a fluoride metal salt and then drying.

  Although it does not specifically limit as said 1st adhesive bond layer (outer adhesive layer) 5, For example, the adhesive bond layer etc. which were formed with the 2 liquid reaction type adhesive agent are mentioned. Examples of the two-component reactive adhesive include a first liquid composed of one or more polyols selected from the group consisting of polyurethane-based polyols, polyester-based polyols, and polyether-based polyols, and a polyisocyanate-containing first liquid. Examples thereof include a two-component reactive adhesive composed of two components (curing agent). For example, the first adhesive layer 5 has an adhesive such as the two-component reactive adhesive on the “upper surface of the metal foil layer 4” and / or “lower surface of the heat-resistant resin layer 2”. It is formed by applying by a technique such as gravure coating.

  The second adhesive layer (inner adhesive layer) 6 is not particularly limited, and examples thereof include polyurethane adhesives, acrylic adhesives, epoxy adhesives, polyolefin adhesives, and elastomer adhesives. And an adhesive layer formed of an adhesive, a fluorine-based adhesive, and the like. Among them, a two-component reactive adhesive composed of a first liquid composed of an acid-modified olefin resin (maleic anhydride-modified polypropylene, maleic anhydride-modified polyethylene, etc.) and a second liquid (curing agent) composed of polyisocyanate. In this case, it is possible to further improve the electrolytic solution resistance and the water vapor barrier property of the outer packaging material 1.

  In addition, in the said embodiment, although the structure which provided the 1st adhesive bond layer 5 and the 2nd adhesive bond layer 6 is employ | adopted, these both layers 5 and 6 are not an indispensable structural layer, These are not included. It is also possible to adopt a configuration that is not provided.

  Thus, by forming the power storage device exterior material 1 according to the present invention (deep drawing molding, stretch molding, etc.), a power storage device exterior case 1A as shown in FIG. 3 can be obtained. The shape of the electricity storage device exterior case 1A is not particularly limited, and examples thereof include a substantially rectangular parallelepiped shape having one surface (upper surface) opened as shown in FIG.

  Next, an embodiment of the electricity storage device 30 according to the present invention is shown in FIG. As shown in FIG. 3, a power storage device main body 31 having a substantially rectangular parallelepiped shape is accommodated in a housing recess of an outer case 1 </ b> A obtained by molding the power storage device exterior material 1 of the present invention. 31 is disposed with the inner layer 3 side thereof inward (lower side), the peripheral portion of the inner layer 3 of the planar outer member 1, and the outer case. The power storage device 30 of the present invention is configured by sealing and sealing the inner layer 3 of the flange portion (sealing peripheral portion) 29 of 1A by heat sealing.

  In FIG. 4, 39 is a heat seal part where the peripheral part of the exterior material 1 and the flange part (sealing peripheral part) 29 of the external case 1A are joined (welded).

  The power storage device main body 31 is not particularly limited, and examples thereof include a battery main body, a capacitor main body, and a capacitor main body.

  Next, specific examples of the present invention will be described, but the present invention is not particularly limited to these examples.

<Spacer used>
(Polyethylene wax A)
Polyethylene wax (waxes) having an average particle size of 9 μm, a weight average molecular weight (Mw) of 3000, a melting point of 120 ° C., and a density of 0.96 g / cm ³
(Polyethylene wax B)
Polyethylene wax (waxes) having an average particle size of 12 μm, a weight average molecular weight (Mw) of 4000, a melting point of 128 ° C., and a density of 0.98 g / cm ³
(Polyethylene wax C)
Polyethylene wax (waxes) having an average particle size of 5 μm, a weight average molecular weight (Mw) of 6000, a melting point of 116 ° C., and a density of 0.95 g / cm ³
(PTFE wax D)
Polytetrafluoroethylene (PTFE) wax (waxes) having an average particle diameter of 2 μm, a weight average molecular weight (Mw) of 5000, a melting point of 320 ° C., and a density of 2.10 g / cm ³
(Low molecular weight polyethylene powder)
Low molecular weight polyethylene (PE) powder (low molecular weight polypropylene powder) having an average particle size of 20 μm, a weight average molecular weight (Mw) of 8500, a melting point of 121 ° C., and a density of 0.94 g / cm ³
Low molecular weight polypropylene (PP) powder having an average particle size of 15 μm, a weight average molecular weight (Mw) of 7000, a melting point of 145 ° C., and a density of 0.89 g / cm ³ .

<Example 1>
100 parts by mass of a polyester polyol having a weight average molecular weight (Mw) of 9800, 15 parts by mass of a trimethylolpropane adduct (HMMP TMP adduct) of hexamethylene diisocyanate as a polyisocyanate, and the above polyethylene wax A (waxes) as a spacer agent 5 parts by mass, 12 parts by mass of acrylic resin beads having an average particle diameter of 2 μm as the first matting agent, 3 parts by mass of barium sulfate having an average particle diameter of 0.8 μm as the second matting agent, a mixed solvent of toluene and methyl ethyl ketone (toluene 100 200 parts by mass) (mass part + 100 parts by mass of methyl ethyl ketone) were mixed to obtain a resin composition A for forming a protective resin layer.

  In this protective resin layer forming resin composition A, the ratio of NCO of the polyisocyanate to OH of the polyester polyol (NCO / OH) was 1.8.

Next, the resin composition A for forming the protective resin layer is gravure roll coated on one surface of a biaxially stretched nylon (6 nylon) film 2 having a thickness of 15 μm obtained by stretching by the simultaneous biaxial stretching method. After applying and drying by the method, the curing reaction was advanced by leaving it in an environment of 60 ° C. for 3 days to form a protective resin layer 7 having a formation amount of 2.5 g / m ² .

On the other hand, a chemical conversion treatment solution composed of polyacrylic acid, chromic acid metal salt, phosphoric acid, water, isopropyl alcohol (IPA) is applied to both surfaces of an aluminum foil (O material defined in JIS A8021) 4 having a thickness of 35 μm. And it dried at 180 degreeC so that chromium adhesion amount might be 10 mg / m < ² >.

  Next, a two-component curable polyester-based polyurethane outer adhesive 5 containing a trimethylolpropane adduct of polyester polyol and tolylene diisocyanate (TMP adduct of TDI) is applied to one surface of the chemical-treated aluminum foil 4. The other surface of the biaxially stretched nylon film 2 (the surface opposite to the side on which the protective resin layer 7 is formed) is bonded, and then the other surface 4a of the aluminum foil 4 is coated with maleic anhydride-modified polypropylene. And an unstretched polypropylene film (heat-fusible resin layer) 3 having a thickness of 30 μm through a two-part curable inner adhesive 6 containing hexamethylene diisocyanate (HMDI), and 5 in an environment of 40 ° C. By leaving it for a day, the exterior | packing material 1 for electrical storage devices shown in FIG. 1 was obtained.

As the unstretched polypropylene film 3, a 4 μm random polypropylene layer (erucic acid amide content 1000 ppm, silica fine particle content 5000 ppm) / 22 μm block polypropylene layer (erucic acid amide content 2000 ppm) / 4 μm random polypropylene layer ( A film having a three-layer structure having an erucic acid amide content of 1000 ppm and a silica fine particle content of 5000 ppm was used. The coating amount of the outer adhesive 5 was set to 3 g / m ² , and the coating amount of the inner adhesive 6 was set to 3 g / m ² .

<Example 2>
1 was obtained in the same manner as in Example 1 except that the blending amount of polyethylene wax A (waxes) in the resin composition for forming a protective resin layer was changed to 10 parts by mass. .

<Example 3>
1 was obtained in the same manner as in Example 1 except that the blending amount of polyethylene wax A (waxes) in the resin composition for forming the protective resin layer was changed to 15 parts by mass. .

<Example 4>
As polyisocyanate, instead of 15 parts by mass of hexamethylene diisocyanate trimethylolpropane adduct (HMDI TMP adduct), 8 parts by mass of hexamethylene diisocyanate trimethylolpropane adduct (HMDI TMP adduct) and tolylene diene 1 was obtained in the same manner as in Example 2, except that 7 parts by mass of an isocyanate trimethylolpropane adduct (TMI adduct of TDI) was used.

<Example 5>
In place of 100 parts by mass of the polyester polyol having an Mw of 9800, 100 parts by mass of the polyurethane polyol having a weight average molecular weight (Mw) of 14500 is used, and in addition to 10 parts by mass of the “polyethylene wax A”, the polyethylene wax B ( Waxes) Except that 10 parts by mass was used, the electricity storage device exterior material 1 shown in FIG. 1 was obtained in the same manner as in Example 4.

<Example 6>
1 was obtained in the same manner as in Example 4 except that 5 parts by mass of the PTFE wax D (wax) was used instead of 10 parts by mass of “polyethylene wax A”. .

<Example 7>
1 was obtained in the same manner as in Example 5 except that 5 parts by mass of the PTFE wax D (wax) was used instead of 10 parts by mass of “polyethylene wax B”. .

<Example 8>
As the first matting agent, in the same manner as in Example 7, except that 12 parts by mass of urethane resin beads having an average particle diameter of 3 μm was used instead of 12 parts by mass of acrylic resin beads having an average particle diameter of 2 μm, FIG. The exterior | packing material 1 for electrical storage devices shown in FIG.

<Example 9>
1 was obtained in the same manner as in Example 8 except that 5 parts by mass of “polyethylene wax C” was used instead of 5 parts by mass of “PTFE wax D”.

<Example 10>
1 was obtained in the same manner as in Example 7 except that 3 parts by mass of the low molecular weight PE powder was used instead of 5 parts by mass of “PTFE wax D”.

<Example 11>
1 was obtained in the same manner as in Example 7 except that 5 parts by mass of the low molecular weight PE powder was used instead of 5 parts by mass of “PTFE wax D”.

<Example 12>
1 was obtained in the same manner as in Example 7 except that 3 parts by mass of the low molecular weight PP powder was used instead of 5 parts by mass of “PTFE wax D”.

<Example 13>
1 was obtained in the same manner as in Example 7 except that 5 parts by mass of the low molecular weight PP powder was used instead of 5 parts by mass of “PTFE wax D”.

<Example 14>
Instead of 100 parts by mass of polyester polyol with Mw of 9800, 100 parts by mass of polyurethane polyol with a weight average molecular weight (Mw) of 14500 is used, and in addition to 5 parts by mass of “polyethylene wax A”, the above low molecular weight PE powder Except having used 3 mass parts, it carried out similarly to Example 1, and obtained the exterior | packing material 1 for electrical storage devices shown in FIG.

<Example 15>
In place of 100 parts by mass of polyester polyol with Mw of 9800, 100 parts by mass of polyurethane polyol with weight average molecular weight (Mw) of 14500 is used, and in addition to 5 parts by mass of “polyethylene wax A”, the above low molecular weight PP powder Except having used 3 mass parts, it carried out similarly to Example 1, and obtained the exterior | packing material 1 for electrical storage devices shown in FIG.

<Comparative Example 1>
An exterior material for an electricity storage device was obtained in the same manner as in Example 1 except that the protective resin layer-forming resin composition was a composition not containing (not containing) polyethylene wax A (spacer agent).

  In Tables 1 and 2, the contents (type, average particle diameter, blending amount) of the first matting agent and the second matting agent are omitted (described in the above Example column).

  Each power storage device exterior material obtained as described above was evaluated based on the following evaluation method. The results are shown in Tables 1 and 2.

  The “projection height H (μm)” in Table 1 is determined by observing a cross-section (see FIG. 2) of the exterior member for an electricity storage device with a SEM (scanning electron microscope). The protrusion height protruding outward from the surface is determined for 10 spacer agent aggregates, and is an average value (protrusion height H) obtained by averaging these 10 protrusion heights.

Further, “area ratio (%) in plan view of the protruding portion having a protruding height of 1 μm or more” in Table 1 indicates that the surface on the protective resin layer side of the exterior member for the electricity storage device is vertically aligned with an SEM (scanning electron microscope). A square area (2500 μm ² ) of 50 μm × width 50 μm is observed in a plan view and means an area ratio obtained by the following equation. That is, the “plan view area of the protruding portion where the protrusion height from which the spacer agent aggregate protrudes outward from the surface of the protective resin layer is 1 μm or more” obtained by the planar view observation with the SEM is “S (μm ² ) ”is the area ratio obtained by the following equation.

Area ratio (%) = (S / 2500) × 100
In addition, the “major axis of the aggregate” in Table 1 is obtained by observing a surface of the protective resin layer side of the exterior member for an electricity storage device in a plan view using a SEM (scanning electron microscope), and by using the SEM in a plan view. The major axis (W) in plan view of the ten spacer agent aggregates was obtained and averaged (average major axis of spacer agent aggregates) (see FIG. 2).

<Abrasion resistance evaluation method>
The aluminum jig is reciprocated 10 times on the surface of the exterior material for the electricity storage device (the surface of the protective resin layer 7) using a Gakushin method friction fastness tester (with an aluminum jig with a load of 200 g) manufactured by Tester Sangyo. After contact, the presence or degree of scratches on the surface was visually examined, and scratch resistance was evaluated based on the following criteria.
(Criteria)
“◯”: no scratches on the surface of the protective resin layer “Δ”: slight scratches are observed on the surface of the protective resin layer, but almost inconspicuous “×”: scratches clearly observed on the surface of the protective resin layer It was done.

<Discoloration prevention evaluation method>
By using an overhang molding machine (product number: TP-25C-X2) manufactured by Amada Co., Ltd. and performing an overhang molding with a holding pressure of 0.3 MPa on the exterior material for the electricity storage device, the length 55 mm × width 35 mm × depth 4 mm A rectangular parallelepiped first case for a power storage device (a rectangular parallelepiped shaped body having an open upper surface) 1A is obtained (see FIG. 3). The both sides of the obtained first exterior case were visually examined for the presence or absence of discoloration and the degree thereof, and the discoloration prevention property was evaluated based on the following criteria. The evaluation results are shown in Table 2.

  In addition, by carrying out overmolding in the same manner as described above with a pressing pressure of 0.25 MPa on the electricity storage device exterior material, a second electricity storage device exterior case with a rectangular parallelepiped shape having a length of 55 mm × width of 35 mm × depth of 6 mm (the upper surface is open) A rectangular parallelepiped shaped product) 1A is obtained (see FIG. 3). The presence or absence of discoloration and the degree thereof were visually examined on both surfaces of the obtained second exterior case, and the discoloration prevention property was evaluated based on the following criteria. The evaluation results are shown in Table 2.

(Criteria)
“◎”: No discoloration was observed on both sides of the exterior case before and after molding. “○”: Extremely slight discoloration was observed on the protective resin layer side surface of the exterior case before and after molding. “△”, which is a level without any defects, is a level in which slight discoloration is recognized before and after molding on the surface on the protective resin layer side of the outer case, and “×” is a level that can be used as a product. Clear discoloration was observed on the side surface before and after molding.

  As is apparent from the table, the power storage device exterior materials of Examples 1 to 15 according to the present invention were excellent in scratch resistance and hardly discolored by molding, and were excellent in discoloration prevention.

  On the other hand, in Comparative Example 1 in which the spacer agent was not added in the protective resin layer, the scratch resistance was insufficient and the discoloration prevention property of discoloration due to molding was inferior.

As a specific example, an exterior material for an electricity storage device according to the present invention is, for example,
-Electric storage devices such as lithium secondary batteries (lithium ion batteries, lithium polymer batteries, etc.)-Used as exterior materials for various electric storage devices such as lithium ion capacitors and electric double layer capacitors. The power storage device according to the present invention includes an all-solid battery in addition to the power storage device exemplified above.

DESCRIPTION OF SYMBOLS 1 ... Exterior material for electrical storage devices 2 ... Heat-resistant resin layer (outer layer)
3 ... Heat-fusible resin layer (inner layer)
4 ... Metal foil layer 7 ... Protective resin layer 8 ... Spacer agent (spacer agent aggregate)
H: Projection height (partial projection height of the spacer agent from the surface of the protective resin layer)
W: Major axis of spacer agent aggregate in plan view

Claims (14)

A heat storage resin layer as an outer layer, a heat-fusible resin layer as an inner layer, and a metal foil layer disposed between these two layers, an exterior material for an electricity storage device,
A protective resin layer is laminated on the outer side of the heat resistant resin layer,
The protective resin layer contains a resin and a spacer agent that is not compatible with the resin,
A part of the spacer agent protrudes outward from the surface of the protective resin layer.   The said spacer agent is the exterior | packing material for electrical storage devices of Claim 1 contained in the said protective resin layer in the form of the aggregate of several spacer agent.   The exterior material for an electricity storage device according to claim 2, wherein an average particle diameter of each spacer agent constituting the aggregate is 1 μm to 20 μm.   The power storage device exterior material according to claim 2 or 3, wherein an average major axis in a plan view of the spacer agent aggregate in the protective resin layer is in the range of 10 µm to 120 µm.   5. The external packaging material for an electricity storage device according to claim 2, wherein the spacer agent aggregate has a protruding height of 1 μm or more protruding outward from the surface of the protective resin layer.   The planar area of the projecting portion where the spacer agent aggregate projects outward from the surface of the protective resin layer is 1 μm or more is 4% to 20% of the entire planar area of the protective resin layer. It is%, The exterior material for electrical storage devices of any one of Claims 2-5.   The protruding height at which the spacer agent aggregate protrudes outward from the surface of the protective resin layer is 0.5 μm to 10 μm, and the average major axis in plan view of the spacer agent aggregate in the protective resin layer is It is the range of 10 micrometers-120 micrometers, The exterior material for electrical storage devices of any one of Claims 2-4.   The electricity storage device exterior material according to any one of claims 1 to 7, wherein the spacer agent is one or more spacer agents selected from the group consisting of waxes and polymer powders.   The melting | fusing point of the said spacer agent is 90 to 350 degreeC, The exterior material for electrical storage devices of any one of Claims 1-8.   The content rate of the said spacer agent in the said protective resin layer is 2 mass%-20 mass%, The exterior material for electrical storage devices of any one of Claims 1-9.   The power storage device exterior material according to any one of claims 1 to 10, wherein the resin is a reaction product resin of a polyol and a polyisocyanate.   The protective resin layer further contains a matting agent composed of fine particles, and the average major axis of the matting agent in the protective resin layer in a plan view of the protective resin layer is in the range of 0.3 μm to 7 μm. The exterior material for an electrical storage device according to any one of 11.   The exterior case for electrical storage devices which consists of a molded object of the exterior material for electrical storage devices of any one of Claims 1-12. An electricity storage device body,
The exterior member for an electrical storage device according to any one of claims 1 to 12 and / or the exterior member comprising the exterior case for an electrical storage device according to claim 13,
The electricity storage device, wherein the electricity storage device body is covered with the exterior member.

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