JP2021152993A - Exterior material for power storage device and power storage device using the same - Google Patents

Abstract

To provide an exterior material for power storage devices, which is capable of securing an excellent heat-seal strength under a high-temperature environment and also capable of securing an excellent heat-seal strength under a room-temperature environment after exposed to a high-temperature environment.SOLUTION: An exterior material for power storage devices includes at least a base material layer, a barrier layer and a sealant layer in this order. The sealant layer includes: polyolefin as a first resin; and a resin, as a second resin, of at least one selected from the group consisting of polyester, polyamide, polycarbonate, and polyphenylene ether.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to an exterior material for a power storage device and a power storage device using the same.

As the power storage device, for example, a secondary battery such as a lithium ion battery, a nickel hydrogen battery, and a lead storage battery, and an electrochemical capacitor such as an electric double layer capacitor are known. Further miniaturization of power storage devices is required due to miniaturization of mobile devices or restrictions on installation space, and lithium ion batteries having 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, and can be manufactured at low cost are now being used.

A lithium ion battery using the multilayer film as an exterior material is called a laminated lithium ion battery. The exterior material covers the battery contents (positive electrode, separator, negative electrode, electrolyte, etc.) to prevent the ingress of moisture into the battery. In a laminated lithium-ion battery, for example, a recess is formed in a part of the exterior material by cold molding, the battery contents are housed in the recess, the remaining part of the exterior material is folded back, and the edge portion is heat-sealed. Manufactured by sealing with (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2013-101765

By the way, as a next-generation battery of a lithium-ion battery, research and development of a power storage device called an all-solid-state battery is being carried out. The all-solid-state battery has a feature that it does not use an organic electrolytic solution as an electrolytic substance but uses a solid electrolyte. Lithium-ion batteries cannot be used under temperature conditions higher than the boiling point temperature of the electrolytic solution (about 80 ° C.), whereas all-solid-state batteries can be used under temperature conditions exceeding 100 ° C. Lithium ion conductivity can be increased by operating under high temperature conditions (eg 100-150 ° C.).

However, when a laminated all-solid-state battery is manufactured using the above-mentioned multilayer film as the exterior material, if the heat resistance of the exterior material is insufficient, the interlayer adhesion in a high temperature environment after heat sealing (Adhesion between layers fused by heat sealing) cannot be ensured, and the heat sealing strength may decrease, resulting in a decrease in the sealing property of the all-solid-state battery package.

Therefore, from the viewpoint of ensuring the heat seal strength in a high temperature environment, the present inventors are studying a method of using a resin having high heat resistance for the sealant layer to be fused by the heat seal. However, when an all-solid-state battery is manufactured using an exterior material using a highly heat-resistant resin for the sealant layer, operated in a high temperature environment, and then returned to room temperature, the heat seal strength in the room temperature environment is obtained. The present inventors have found that the problem of a decrease in the amount of water is generated.

The present disclosure has been made in view of the above problems, and is capable of ensuring excellent heat-sealing strength in a high-temperature environment and storage capacity capable of ensuring excellent heat-sealing strength in a room temperature environment after being exposed to a high-temperature environment. It is an object of the present invention to provide an exterior material for an apparatus and a power storage device using the same.

In order to achieve the above object, the present disclosure is an exterior material for a power storage device including at least a base material layer, a barrier layer, and a sealant layer in this order, wherein the sealant layer is a polyolefin as a first resin. Provided is an exterior material for a power storage device, which comprises at least one resin selected from the group consisting of polyester, polyamide, polycarbonate and polyphenylene ether as a second resin.

By using the second resin, the heat seal strength of the exterior material in a high temperature environment can be improved. However, when the second resin is used alone, when the exterior material is exposed to a high temperature environment and then returned to room temperature, the heat seal strength in the room temperature environment is higher than that before the exposure to the high temperature environment. The present inventors have found that it is lowered and it becomes difficult to secure excellent heat seal strength. The second resin is a resin having high heat resistance, and although its performance when used in a high temperature environment has been investigated, the heat seal strength in a room temperature environment is before and after exposure to a high temperature environment. Until now, sufficient consideration has not been given to changes. Since the all-solid-state battery is repeatedly placed in a high temperature environment when it is used and in a room temperature environment when it is not used, it is necessary that the heat seal strength of the exterior material does not deteriorate even in such a use environment. Therefore, as a result of diligent studies, the present inventors have reduced the heat seal strength in a room temperature environment after being exposed to a high temperature environment by using the first resin in combination with the second resin. It was found that it can be suppressed. That is, according to the exterior material for a power storage device, excellent heat seal strength can be ensured in a high temperature environment by using a specific first resin and a specific second resin in combination as the material of the sealant layer. It is possible to secure excellent heat seal strength in a room temperature environment after being exposed to a high temperature environment.

In the exterior material for a power storage device, the first resin may contain a modified polyolefin having a polar group capable of reacting with the second resin. Further, the modified polyolefin may be a polyolefin modified with maleic anhydride. The compatibility between the first resin and the second resin is not always good, and the dispersibility may be insufficient, so that the above-mentioned combined effect may not be sufficiently obtained. On the other hand, when the first resin contains a modified polyolefin having a polar group capable of reacting with the second resin, the compatibility between the first resin and the second resin is enhanced and the dispersibility is improved. Can be done. As a result, the synergistic effect of the combined use of the first resin and the second resin can be more sufficiently obtained, more excellent heat seal strength can be ensured in a high temperature environment, and after exposure to a high temperature environment. It is possible to secure better heat seal strength in a room temperature environment. Further, when the modified polyolefin is a polyolefin modified with maleic anhydride, the above effect can be more sufficiently obtained.

Here, the first resin may contain the above-mentioned modified polyolefin and a polyolefin having no polar group capable of reacting with the second resin (unmodified polyolefin). Since modified polyolefins tend to decrease in melting point and molecular weight due to modification, the decrease in heat seal strength in a high temperature environment can be suppressed by using a combination of ordinary polyolefins (unmodified polyolefins). .. When the modified polyolefin and the unmodified polyolefin are used in combination, the modified polyolefin plays a role as a compatibilizer, and the dispersibility between the unmodified polyolefin and the second resin can be improved.

In the exterior material for a power storage device, the sealant layer contains the polyester and / or the polyamide, and the sealant layer is heat-sealed under the conditions of 260 ° C., 0.5 MPa for 3 seconds, and cooled to 25 ° C. The crystallinity of the polyester and / or the polyamide may be 10% or more and less than 70%. When the crystallinity of the polyester and / or polyamide measured by the above method is within the above range, the heat seal strength in a high temperature environment can be further improved, and the flexibility of the exterior material can be further improved.

In the exterior material for a power storage device, a corrosion prevention treatment layer may be provided on one or both surfaces of the barrier layer. By providing the corrosion prevention treatment layer, corrosion of the barrier layer can be prevented, and by interposing the corrosion prevention treatment layer, the adhesion between the barrier layer and the adjacent layer can be enhanced. Further, the all-solid battery, it is possible to sulfide-based material is used as the electrolyte, when water has penetrated inside the exterior material, hydrogen sulfide reacts with water sulfide compound (H 2 _S) Occurs. This H ₂ S may reduce the adhesion between the barrier layer and the layer adjacent to it. However, in the case of using the exterior material for the electric storage device as an exterior material of the all-solid-state battery, by providing the corrosion prevention treatment layer on the barrier layer surface, it is possible to impart resistance to H _{2 S} resistance to the barrier layer, the barrier layer It is possible to prevent a decrease in the adhesion between the and the layer adjacent thereto. Therefore, according to the exterior material for the power storage device, excellent heat seal strength can be ensured in a high temperature environment even when exposed to hydrogen sulfide, and in a room temperature environment after being exposed to a high temperature environment. It is possible to secure the excellent heat seal strength of.

In the exterior material for a power storage device, when the base material layer side of the exterior material for a power storage device is on the outside and the sealant layer side is on the inside, at least one of the layers arranged inside the barrier layer. However, it may contain a hydrogen sulfide adsorbent. As described above, although the all-solid battery which may hydrogen sulfide (H 2 _S) is generated by containing at least one layer of hydrogen sulfide sorbent material of the layers disposed inside the barrier layer, A layer containing a hydrogen sulfide adsorbent _{can adsorb H 2} S generated inside the exterior material and detoxify it, and the H ₂ S contains a barrier layer, a current collector (particularly copper foil), and Ni. The positive electrode can be protected at a higher level. Therefore, according to the exterior material for the power storage device, excellent heat seal strength can be ensured in a high temperature environment even when exposed to hydrogen sulfide, and in a room temperature environment after being exposed to a high temperature environment. It is possible to secure the excellent heat seal strength of.

The exterior material for the power storage device may be for an all-solid-state battery.

The present disclosure also includes a power storage device main body, a current take-out terminal extending from the power storage device main body, and an exterior material for a power storage device of the present disclosure that sandwiches the current take-out terminal and accommodates the power storage device main body. Provide a power storage device including. The power storage device may be an all-solid-state battery.

According to the present disclosure, an exterior material for a power storage device that can secure excellent heat-sealing strength in a high-temperature environment and also can secure excellent heat-sealing strength in a room temperature environment after being exposed to a high-temperature environment, and the use thereof. It is possible to provide a power storage device that has been used.

It is the schematic sectional drawing of the exterior material for a power storage device which concerns on one Embodiment of this disclosure. It is the schematic sectional drawing of the exterior material for a power storage device which concerns on one Embodiment of this disclosure. It is a perspective view of the power storage device which concerns on one Embodiment of this disclosure. It is a schematic diagram explaining the method of making the sample for heat seal strength measurement in an Example.

Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the drawings as appropriate. In the drawings, the same or corresponding parts are designated by the same reference numerals, and duplicate description will be omitted. Further, the dimensional ratio in the drawing is not limited to the ratio shown in the drawing.

[Exterior material for power storage device]
FIG. 1 is a cross-sectional view schematically showing an embodiment of the exterior material for a power storage device of the present disclosure. As shown in FIG. 1, the exterior material (exterior material for power storage device) 10 of the present embodiment includes a base material layer 11 and a first adhesive layer 12a provided on one surface side of the base material layer 11. The barrier layer 13 having the first and second corrosion prevention treatment layers 14a and 14b on both sides provided on the side opposite to the base material layer 11 of the first adhesive layer 12a, and the barrier layer 13 A second adhesive layer 12b provided on the side opposite to the first adhesive layer 12a, and a sealant layer 16 provided on the side opposite to the barrier layer 13 of the second adhesive layer 12b. Is a laminated body in which is laminated. Here, the first corrosion prevention treatment layer 14a is provided on the surface of the barrier layer 13 on the base material layer 11 side, and the second corrosion prevention treatment layer 14b is provided on the surface of the barrier layer 13 on the sealant layer 16 side. There is. In the exterior material 10, the base material layer 11 is the outermost layer and the sealant layer 16 is the innermost layer. That is, the exterior material 10 is used with the base material layer 11 facing the outside of the power storage device and the sealant layer 16 facing the inside of the power storage device.

In the exterior material 10 of the present embodiment, the sealant layer 16 comprises polyolefin as a first resin and at least one resin selected from the group consisting of polyester, polyamide, polycarbonate and polyphenylene ether as a second resin. include. Hereinafter, each layer constituting the exterior material 10 will be specifically described.

<Base material layer 11>
The base material layer 11 imparts heat resistance in the sealing process when manufacturing the power storage device, and plays a role of suppressing the generation of pinholes that may occur during molding processing and distribution. In particular, in the case of an exterior material of a power storage device for large-scale applications, scratch resistance, chemical resistance, insulation and the like can be imparted.

The base material layer 11 is preferably a layer formed of an insulating resin. Resins include polyester resin, polyamide resin, polyimide resin, polyamideimide resin, polyether ketone resin, polyphenylene sulfide resin, polyetherimide resin, polysulphon resin, fluororesin, phenol resin, melamine resin, urethane resin, allyl resin, etc. Silicon resin, epoxy resin, furan resin, acetyl cellulose resin and the like can be used.

When applied to the base material layer 11, these resins may be in either a stretched or unstretched film form or a coating film form. Also. The base material layer 11 may be a single layer or a multi-layer, and in the case of a multi-layer, different resins can be used in combination. If it is a film, it can be extruded together or laminated with an adhesive. In the case of a coating film, one coated for the number of times of lamination can be used, and the film and the coating film can be combined to form a multilayer.

Among these resins, polyester resin and polyamide resin are preferable as the base material layer 11 because they are excellent in moldability. Examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. Examples of the polyamide resin constituting the polyamide film include nylon 6, nylon 6, 6, a copolymer of nylon 6 and nylon 6, 6, nylon 6, nylon 9T, nylon 10, and polymethoxylylen adipamide (MXD6). ), Nylon 11, nylon 12, and the like.

When these resins are used in the form of a film, it is preferably a biaxially stretched film. Examples of the stretching method in the biaxially stretched film include a sequential biaxial stretching method, a tubular biaxial stretching method, and a simultaneous biaxial stretching method. The biaxially stretched film is preferably stretched by the tubular biaxial stretching method from the viewpoint of obtaining more excellent deep drawing moldability.

The thickness of the base material layer 11 is preferably 6 to 40 μm, more preferably 10 to 30 μm. When the thickness of the base material layer 11 is 6 μm or more, the pinhole resistance and the insulating property of the exterior material 10 tend to be improved. When the thickness of the base material layer 11 exceeds 40 μm, the total thickness of the exterior material 10 tends to increase.

The melting point peak temperature of the base material layer 11 is higher than the melting point peak temperature of the sealant layer 16 and further higher than the melting point peak temperature of the sealant layer 16 by 30 ° C. or more in order to suppress the deformation of the base material layer 11 at the time of sealing. Is preferable.

<First adhesive layer 12a>
The first adhesive layer 12a is a layer that adheres the base material layer 11 and the barrier layer 13. Specific examples of the material constituting the first adhesive layer 12a include bifunctional or higher functional isocyanate compounds (polyfunctional isocyanate compounds) with respect to main agents such as polyester polyols, polyether polyols, acrylic polyols, and carbonate polyols. ), And the like. The various polyols described above can be used alone or in combination of two or more, depending on the function and performance required for the exterior material 10. In addition to the above, it is also possible to use an epoxy resin as a main agent and a curing agent, but the present invention is not limited to this. Further, various other additives and stabilizers may be added to the above-mentioned adhesive depending on the performance required for the adhesive.

The thickness of the first adhesive layer 12a is not particularly limited, but is preferably 1 to 10 μm, preferably 2 to 7 μm, from the viewpoint of obtaining desired adhesive strength, followability, processability, and the like. More preferred.

<Barrier layer 13>
The barrier layer 13 has a water vapor barrier property that prevents moisture from entering the inside of the power storage device. Further, the barrier layer 13 may have ductility for deep drawing molding. The barrier layer 13 includes, for example, various metal foils such as aluminum, stainless steel, and copper, a metal vapor deposition film, an inorganic oxide vapor deposition film, a carbon-containing inorganic oxide vapor deposition film, and a film provided with these vapor deposition films. Can be used. As the film provided with the vapor-deposited film, for example, an aluminum-deposited film or an inorganic oxide-deposited film can be used. These can be used alone or in combination of two or more. As the barrier layer 13, a metal foil is preferable, and an aluminum foil is more preferable, from the viewpoints of mass (specific gravity), moisture resistance, processability, and cost.

As the aluminum foil, a soft aluminum foil that has been subjected to a quenching treatment can be particularly preferably used from the viewpoint of imparting a desired ductility during molding, but further pinhole resistance and ductility during molding are imparted. For the purpose, it is more preferable to use an aluminum foil containing iron. The iron content in the aluminum foil is preferably 0.1 to 9.0% by mass, more preferably 0.5 to 2.0% by mass, based on 100% by mass of the aluminum foil. When the iron content is 0.1% by mass or more, the exterior material 10 having more excellent pinhole resistance and ductility can be obtained. When the iron content is 9.0% by mass or less, the exterior material 10 having more excellent flexibility can be obtained. As the aluminum foil, an untreated aluminum foil may be used, but it is preferable to use a degreased aluminum foil from the viewpoint of imparting corrosion resistance. When the aluminum foil is degreased, only one side of the aluminum foil may be degreased, or both sides may be degreased.

The thickness of the barrier layer 13 is not particularly limited, but is preferably 9 to 200 μm in consideration of barrier properties, pinhole resistance, and workability, and more preferably 15 to 100 μm.

<First and second corrosion prevention treatment layers 14a, 14b>
The first and second corrosion prevention treatment layers 14a and 14b are layers provided to prevent corrosion of the metal foil (metal foil layer) and the like constituting the barrier layer 13. Further, the first corrosion prevention treatment layer 14a plays a role of enhancing the adhesion between the barrier layer 13 and the first adhesive layer 12a. Further, the second corrosion prevention treatment layer 14b plays a role of enhancing the adhesion between the barrier layer 13 and the second adhesive layer 12b. The first corrosion prevention treatment layer 14a and the second corrosion prevention treatment layer 14b may have the same structure or may have different structures. Examples of the first and second corrosion prevention treatment layers 14a and 14b (hereinafter, also simply referred to as “corrosion prevention treatment layers 14a and 14b”) include degreasing treatment, hydrothermal transformation treatment, anodization treatment, chemical conversion treatment, or the like. It is formed by a combination of these processes.

Examples of the degreasing treatment include acid degreasing and alkaline degreasing. Examples of the acid degreasing include a method in which an inorganic acid such as sulfuric acid, nitric acid, hydrochloric acid, or hydrofluoric acid is used alone, or a mixed solution thereof is used. Further, as the acid degreasing, by using an acid degreasing agent in which a fluorine-containing compound such as monosodium difluoride is dissolved in the above-mentioned inorganic acid, the degreasing effect of aluminum is particularly effective when an aluminum foil is used for the barrier layer 13. It is effective in terms of corrosion resistance because it can form an immobile aluminum fluoride. Examples of the alkaline degreasing include a method using sodium hydroxide and the like.

Examples of the hot water transformation treatment include a boehmite treatment in which an aluminum foil is immersed in boiling water to which triethanolamine is added. Examples of the anodizing treatment include alumite treatment.

Examples of the chemical conversion treatment include a dipping type and a coating type. Examples of the immersion type chemical treatment include chromate treatment, zirconium treatment, titanium treatment, vanadium treatment, molybdenum treatment, calcium phosphate treatment, strontium hydroxide treatment, cerium treatment, ruthenium treatment, and various chemical treatments consisting of a mixed phase thereof. Be done. On the other hand, as a coating type chemical conversion treatment, a method of coating a coating agent having corrosion prevention performance on the barrier layer 13 can be mentioned.

Of these corrosion prevention treatments, when at least a part of the corrosion prevention treatment layer is formed by any of the hydrothermal transformation treatment, the anodizing treatment, and the chemical conversion treatment, it is preferable to perform the above-mentioned degreasing treatment in advance. When a metal foil that has been degreased, such as a metal foil that has undergone an annealing step, is used as the barrier layer 13, it is necessary to perform degreasing treatment again in the formation of the corrosion prevention treatment layers 14a and 14b.

The coating agent used for the coating type chemical conversion treatment preferably contains trivalent chromium. Further, the coating agent may contain at least one polymer selected from the group consisting of the cationic polymer and the anionic polymer described later.

Further, among the above treatments, particularly in the hydrothermal transformation treatment and the anodizing treatment, the aluminum foil surface is dissolved by the treatment agent to form aluminum compounds (boehmite, alumite) having excellent corrosion resistance. Therefore, the barrier layer 13 using the aluminum foil to the corrosion prevention treatment layers 14a and 14b form a co-continuous structure, and the above treatment is included in the definition of the chemical conversion treatment. On the other hand, as will be described later, it is also possible to form the corrosion prevention treatment layers 14a and 14b only by a pure coating method which is not included in the definition of chemical conversion treatment. As this method, for example, a sol of a rare earth element oxide such as cerium oxide having an average particle size of 100 nm or less is used as a material having an anticorrosion effect (inhibitor effect) of aluminum and also being environmentally suitable. The method to be used can be mentioned. By using this method, it is possible to impart a corrosion prevention effect to a metal foil such as an aluminum foil even with a general coating method.

Examples of the rare earth element oxide sol include sol using various solvents such as water-based, alcohol-based, hydrocarbon-based, ketone-based, ester-based, and ether-based solvents. Of these, aqueous sol is preferable.

In the sol of the rare earth element oxide, inorganic acids such as nitric acid, hydrochloric acid and phosphoric acid or salts thereof, and organic acids such as acetic acid, apple acid, ascorbic acid and lactic acid are usually dispersed and stabilized in order to stabilize the dispersion. Used as an agent. Among these dispersion stabilizers, phosphoric acid, in particular, is used in the exterior material 10 to (1) stabilize the dispersion of the sol, and (2) improve the adhesion to the barrier layer 13 by utilizing the aluminum chelating ability of phosphoric acid. (3) Conferring corrosion resistance by capturing (immobilizing) aluminum ions eluted by the influence of acid and corrosive gas, (4) Corrosion prevention treatment layer by easily causing dehydration condensation of phosphoric acid even at low temperature (4) It is expected that the cohesive force of the oxide layer) 14a and 14b will be improved.

Since the corrosion prevention treatment layers 14a and 14b formed by the rare earth element oxide sol are aggregates of inorganic particles, the cohesive force of the layers themselves may decrease even after the drying cure step. Therefore, the corrosion prevention treatment layers 14a and 14b in this case are preferably composited with an anionic polymer or a cationic polymer in order to supplement the cohesive force.

The corrosion prevention treatment layers 14a and 14b are not limited to the above-mentioned layers. For example, it may be formed by using a treatment agent in which a phosphoric acid and a chromium compound are mixed in a resin binder (aminophenol or the like), such as coating type chromate which is a known technique. By using this treatment agent, it is possible to obtain a layer having both a corrosion prevention function and adhesion. In addition, although it is necessary to consider the stability of the coating liquid, a coating agent in which a rare earth element oxide sol and a polycationic polymer or a polyanionic polymer are preliminarily liquefied is used for both corrosion prevention function and adhesion. It can be a layer that combines.

Corrosion treatment layer 14a, per unit area of the 14b mass, multilayer structure, be either single-layer structure, preferably ^{0.005~0.200g / m 2, 0.010~0.100g / m} 2 Is more preferable. When the mass per unit area is 0.005 g / m ² or more, it is easy to impart the corrosion prevention function to the barrier layer 13. Further, even if the mass per unit area ^{exceeds 0.200 g / m 2} , the corrosion prevention function does not change much. On the other hand, when a rare earth element oxide sol is used, if the coating film is thick, curing due to heat during drying may be insufficient, and the cohesive force may be lowered. The thickness of the corrosion prevention treatment layers 14a and 14b can be converted from their specific gravities.

From the viewpoint of facilitating the adhesion between the sealant layer and the barrier layer, the corrosion prevention treatment layers 14a and 14b are, for example, cerium oxide and 1 to 100 parts by mass of phosphoric acid with respect to 100 parts by mass of the cerium oxide. It may be an embodiment containing a phosphate and a cationic polymer, or it may be formed by subjecting the barrier layer 13 to a chemical conversion treatment, or it may be formed by subjecting the barrier layer 13 to a chemical conversion treatment. And may be an embodiment containing a cationic polymer.

<Second adhesive layer 12b>
The second adhesive layer 12b is a layer that adheres the barrier layer 13 and the sealant layer 16. For the second adhesive layer 12b, a general adhesive for adhering the barrier layer 13 and the sealant layer 16 can be used.

A corrosion prevention treatment layer 14b is provided on the barrier layer 13, and the second corrosion prevention treatment layer 14b contains at least one polymer selected from the group consisting of the above-mentioned cationic polymer and anionic polymer. When having a layer, the second adhesive layer 12b is a layer containing a compound (hereinafter, also referred to as “reactive compound”) that is reactive with the polymer contained in the second corrosion prevention treatment layer 14b. Is preferable.

For example, when the second corrosion protection treatment layer 14b contains a cationic polymer, the second adhesive layer 12b contains a compound that is reactive with the cationic polymer. When the second corrosion protection treatment layer 14b contains an anionic polymer, the second adhesive layer 12b contains a compound that is reactive with the anionic polymer. When the second corrosion prevention treatment layer 14b contains a cationic polymer and an anionic polymer, the second adhesive layer 12b contains a compound that is reactive with the cationic polymer and a compound that is reactive with the anionic polymer. And include. However, the second adhesive layer 12b does not necessarily have to contain the above two kinds of compounds, and may contain a compound having reactivity with both a cationic polymer and an anionic polymer. Here, "reactive" means forming a covalent bond with a cationic polymer or an anionic polymer. Further, the second adhesive layer 12b may further contain an acid-modified polyolefin resin.

Examples of the compound having reactivity with the cationic polymer include at least one compound selected from the group consisting of a polyfunctional isocyanate compound, a glycidyl compound, a compound having a carboxy group, and a compound having an oxazoline group.

Examples of these polyfunctional isocyanate compounds, glycidyl compounds, compounds having a carboxy group, and compounds having an oxazoline group include polyfunctional isocyanate compounds, glycidyl compounds, and carboxy groups exemplified above as cross-linking agents for forming a cationic polymer into a cross-linking structure. Examples thereof include a compound having a oxazoline group and a compound having an oxazoline group. Among these, a polyfunctional isocyanate compound is preferable because it has high reactivity with a cationic polymer and easily forms a crosslinked structure.

Examples of the compound having reactivity with the anionic polymer include at least one compound selected from the group consisting of a glycidyl compound and a compound having an oxazoline group. Examples of these glycidyl compounds and compounds having an oxazoline group include glycidyl compounds exemplified above as a cross-linking agent for forming a cationic polymer into a cross-linked structure, and compounds having an oxazoline group. Among these, the glycidyl compound is preferable because it has high reactivity with the anionic polymer.

When the second adhesive layer 12b contains an acid-modified polyolefin resin, it is preferable that the reactive compound is also reactive with the acidic group in the acid-modified polyolefin resin (that is, forms a covalent bond with the acidic group). As a result, the adhesiveness with the second corrosion prevention treatment layer 14b is further enhanced. In addition, the acid-modified polyolefin resin has a crosslinked structure, and the solvent resistance of the exterior material 10 is further improved.

The content of the reactive compound is preferably equal to 10 times the equivalent amount of the acidic group in the acid-modified polyolefin resin. When the amount is equal to or more than the equal amount, the reactive compound sufficiently reacts with the acidic group in the acid-modified polyolefin resin. On the other hand, if the amount exceeds 10 times the equivalent amount, the cross-linking reaction with the acid-modified polyolefin resin has reached sufficient saturation, so that unreacted substances are present and there is a concern that various performances may be deteriorated. Therefore, for example, the content of the reactive compound is preferably 5 to 20 parts by mass (solid content ratio) with respect to 100 parts by mass of the acid-modified polyolefin resin.

The acid-modified polyolefin resin is one in which an acidic group is introduced into the polyolefin resin. Examples of the acidic group include a carboxy group, a sulfonic acid group, an acid anhydride group and the like, and a maleic anhydride group and a (meth) acrylic acid group are particularly preferable. As the acid-modified polyolefin resin, for example, the same modified polyolefin resin used for the sealant layer 16 can be used.

Various additives such as a flame retardant, a slip agent, an anti-blocking agent, an antioxidant, a light stabilizer, and a tackifier may be blended in the second adhesive layer 12b.

The second adhesive layer 12b is, for example, an acid-modified polyolefin from the viewpoint of suppressing a decrease in laminate strength when a corrosive gas such as hydrogen sulfide or an electrolytic solution is involved and further suppressing a decrease in insulating property. , A polyfunctional isocyanate compound, a glycidyl compound, a compound having a carboxy group, a compound having an oxazoline group, and at least one curing agent selected from the group consisting of a carbodiimide compound. Examples of the carbodiimide compound include N, N'-di-o-toluyl carbodiimide, N, N'-diphenylcarbodiimide, N, N'-di-2,6-dimethylphenylcarbodiimide, N, N'-bis. (2,6-diisopropylphenyl) Carbodiimide, N, N'-dioctyldecylcarbodiimide, N-triyl-N'-cyclohexylcarbodiimide, N, N'-di-2,2-di-t-butylphenylcarbodiimide, N- Triyl-N'-phenylcarbodiimide, N, N'-di-p-nitrophenylcarbodiimide, N, N'-di-p-aminophenylcarbodiimide, N, N'-di-p-hydroxyphenylcarbodiimide, N, N '-Di-cyclohexylcarbodiimide, N, N'-di-p-toluyl carbodiimide and the like can be mentioned.

Further, as the adhesive forming the second adhesive layer 12b, for example, a polyurethane-based adhesive in which a polyester polyol composed of a hydrogenated dimer fatty acid and a diol and a polyisocyanate are mixed can be used. As an adhesive, a polyurethane resin in which a bifunctional or higher-functional isocyanate compound is allowed to act on a main agent such as a polyester polyol, a polyether polyol, an acrylic polyol, or a carbonate polyol, or an epoxy resin in which an amine compound or the like is allowed to act on a main agent having an epoxy group. Etc., which are preferable from the viewpoint of heat resistance.

The thickness of the second adhesive layer 12b is not particularly limited, but is preferably 1 to 10 μm, more preferably 2 to 7 μm, from the viewpoint of obtaining desired adhesive strength, processability, and the like.

<Sealant layer 16>
The sealant layer 16 is a layer that imparts sealing properties to the exterior material 10 by heat sealing, and is a layer that is arranged inside when the power storage device is assembled and is heat-sealed (heat-sealed).

The sealant layer 16 contains a polyolefin as a first resin and at least one resin selected from the group consisting of polyester, polyamide, polycarbonate and polyphenylene ether as a second resin.

Examples of the polyolefin include polyethylenes such as low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene (MDPE) and high density polyethylene (HDPE); ethylene-α olefin copolymer; polypropylene; Examples thereof include block or random copolymers containing propylene as a copolymerization component; propylene-α-olefin copolymer; and polybutene. Among these, polypropylene is preferably used from the viewpoint of heat resistance and flexibility, and particularly block polypropylene (block PP) is more preferably used. As the above-mentioned polyolefin, one type may be used alone, or two or more types may be mixed and used.

The polyolefin preferably contains a modified polyolefin having a polar group capable of reacting with the second resin. Here, examples of the functional group contained in the second resin include the following functional groups. When the second resin is polyester, examples of its functional group include a terminal hydroxyl group, a terminal carboxyl group, and an ester bond. When the second resin is polyamide, examples of its functional group include a terminal amino group and an amide bond. When the second resin is polycarbonate, the functional group thereof is, for example, a terminal hydroxyl group. And an ester bond. When the second resin is a polyphenylene ether, examples of the functional group thereof include a terminal hydroxyl group.

Examples of the polar group capable of reacting with the functional group of the second resin include a hydroxyl group, an acid-modified (ester) group, an aldehyde group, an oxazoline group, and a glycidyl group when the second resin is polyester or polycarbonate. Examples thereof include an amide group and an imino group. When the second resin is a polyamide, examples of the polar group include a hydroxyl group, an acid-modified (ester) group, an aldehyde group, and a glycidyl group. When the second resin is a polyphenylene ether, examples of the polar group include an acid-modified (ester) group, an oxazoline group, a glycidyl group, an amide group, and an imino group.

As the modified polyolefin having a hydroxyl group as a polar group, "Poval" manufactured by Kuraray Co., Ltd., "Mersen H" manufactured by Tosoh Co., Ltd. and the like are commercially available. As the modified polyolefin having a glycidyl group as a polar group, "Modiper" manufactured by NOF Corporation, "LOTADER" and "BONDINE" manufactured by Arkema, etc. are commercially available. As the modified polyolefin having an amide group as a polar group, "APOLHYA" manufactured by Arkema Co., Ltd. and the like are commercially available. As a modified polyolefin having an imino group as a polar group, "Admer IP" manufactured by Mitsui Chemicals, Inc. and the like are commercially available. As a modified polyolefin having an oxazoline group as a polar group, "Epocross" manufactured by Nippon Shokubai Co., Ltd. is commercially available.

Examples of the acid-modified modified polyolefin include an acid-modified poreolefin modified with any one of an unsaturated carboxylic acid, an acid anhydride of the unsaturated carboxylic acid, and an ester of the unsaturated carboxylic acid.

Specifically, as unsaturated carboxylic acids, for example, acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, tetrahydrophthalic acid, bicyclo [2,2,1] hept-2-ene-5, 6-Dicarboxylic acid and the like can be mentioned.

Examples of the acid anhydride of the unsaturated carboxylic acid include maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, and bicyclo [2,2,1] hept-2-ene-5,6-dicarboxylic acid anhydride. Examples thereof include acid anhydrides of unsaturated carboxylic acids such as substances.

Examples of the ester of unsaturated carboxylic acid include methyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dimethyl maleate, monomethyl maleate, diethyl fumarate, dimethyl itacone, diethyl citraconate, and tetrahydrophthalic anhydride. Examples thereof include esters of unsaturated carboxylic acids such as dimethyl and dimethyl bicyclo [2,2,1] hept-2-ene-5,6-dicarboxylic acid.

Specific products of the acid-modified polyolefin include, for example, the following. Examples of those modified with maleic anhydride include "Admer" manufactured by Mitsui Chemicals, "Modic" manufactured by Mitsubishi Chemical, "Toyo Tuck" manufactured by Toyobo, and "Sun Stack" manufactured by Sanyo Chemicals. Can be mentioned. Examples of the acid-modified polyolefin having a carboxyl group as a polar group include "Nucrel" and "Hymilan" manufactured by Mitsui-DuPont Polychemical Co., Ltd. (ionomer type can also be used). Examples of the acid-modified polyolefin having an ester group as a polar group include "Evaflex" manufactured by Mitsui-DuPont Polychemical Co., Ltd., "LOTADER", "BONDINE" and "EVATANE" manufactured by Arkema.

As the acid-modified polyolefin, a polyolefin modified with maleic anhydride is preferable. The above-mentioned modified polyolefin may be used alone or in combination of two or more.

Examples of the polyester as the second resin include those obtained by reacting an acid component with a glycol component. Examples of the acid component include phthalic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, cyclohexanedicarboxylic acid, adipic acid, sebacic acid and the like. Examples of the glycol component include ethylene glycol, butanediol, pentanediol, hexanediol, neopentyl glycol, diethylene glycol, polytetramethylene glycol, cyclohexanedimethanol, and propanediol. Specific examples of the polyester include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polycyclohexanedimethylene terephthalate (PCT) and the like.

Examples of the polyamide as the second resin include nylon-based polyamides such as nylon 6, nylon 11, nylon 12, nylon 6, and 6, and aramid-based polyamides having an aromatic character.

When polyester and / or polyamide is used as the second resin, the sealant layer 16 containing polyester and / or polyamide is heat-sealed at 260 ° C., 0.5 MPa for 3 seconds, cooled to 25 ° C., and then polyester. And / or the degree of crystallinity of the polyamide is preferably 10% or more and less than 70%. If the crystallinity of the polyester and / or polyamide measured by the above method is too low, the heat seal strength in a high temperature environment tends to decrease, and if it is too high, the flexibility tends to decrease. From the viewpoint of achieving both heat seal strength and flexibility in a high temperature environment, the crystallinity is more preferably 15% or more and less than 50%. Since polycarbonate and polyphenylene ether are amorphous, there is no preferable range of crystallinity.

As the second resin, one type may be used alone, or two or more types may be mixed and used.

The content of the first resin in the sealant layer 16 is preferably 10 to 80% by mass, preferably 20 to 70% by mass, based on the total amount of the first resin and the second resin in the sealant layer 16. More preferably, it is more preferably 40 to 60% by mass. When the content of the first resin is 10% by mass or more, it is easier to sufficiently secure excellent heat seal strength in a room temperature environment after being exposed to a high temperature environment, and it is 80% by mass or less. Therefore, it is easy to secure better heat seal strength in a high temperature environment. The first resin and the second resin may be melt-kneaded in advance using a kneader or the like.

The content of the modified polyolefin in the first resin is preferably 0.1 to 100% by mass, more preferably 0.5 to 40% by mass, based on the total amount of the first resin. When the content of the modified polyolefin is 0.1% by mass or more, the polar group of the modified polyolefin and the functional group of the second resin easily react with each other, and the compatibility between the first resin and the second resin becomes compatible. Easy to improve. The content of the modified polyolefin in the first resin may be 100% by mass, but if the melting point of the modified polyolefin is low, the heat seal strength in a high temperature environment may decrease, so 40% by mass. The following is more preferable.

The sealant layer 16 may contain components other than the first resin and the second resin. For example, the sealant layer 16 may contain a component such as an elastomer from the viewpoint of imparting impact resistance. Further, the sealant layer 16 is provided with an antioxidant, a slip agent, a flame retardant, an antiblocking agent, a light stabilizer, a dehydrating agent, a tackifier, and a crystal nucleating agent in order to impart sealing properties, heat resistance and other functionality. It may contain additives such as.

The sealant layer 16 may be a single-layer film or a multilayer film, and may be selected according to a required function. When the sealant layer 16 has a multi-layer structure, each layer may be laminated by coextrusion or may be laminated by dry lamination. When the sealant layer 16 has a multi-layer structure, at least one layer may contain the first resin and the second resin, but from the viewpoint of more sufficiently obtaining the effects of the present disclosure, all the layers are the first resin. And a second resin may be included.

The thickness of the sealant layer 16 (total thickness in the case of multiple layers) is preferably 10 to 150 μm, more preferably 20 to 100 μm. When the thickness of the sealant layer 16 is 10 μm or more, sufficient heat seal strength can be obtained, and when it is 150 μm or less, the amount of water vapor infiltrated from the end portion of the exterior material can be reduced.

The melting peak temperature of the sealant layer varies depending on the application, but in the case of an exterior material for an all-solid-state battery, it is preferably 160 to 280 ° C. because heat resistance is improved.

Although the preferred embodiment of the exterior material for the power storage device of the present embodiment has been described in detail above, the present disclosure is not limited to such a specific embodiment, and the present disclosure described within the scope of the claims. Various modifications and changes are possible within the scope of the gist of.

For example, FIG. 1 shows a case where the corrosion prevention treatment layers 14a and 14b are provided on both sides of the barrier layer 13, but only one of the corrosion prevention treatment layers 14a and 14b may be provided. The corrosion prevention treatment layer may not be provided.

FIG. 1 shows a case where the barrier layer 13 and the sealant layer 16 are laminated by using the second adhesive layer 12b, but as in the case where the exterior material 20 for a power storage device shown in FIG. 2 is used, the second The sealant layer 16 and the barrier layer 13 may be directly laminated without interposing the adhesive layer 12b. Even in this case, since the sealant layer 16 contains the first resin and the second resin, good adhesion between the sealant layer 16 and the barrier layer 13 can be obtained. This is because the second resin, polyester, polyamide, etc., has adhesiveness to the barrier layer. Further, when the first resin has a polar group, the adhesion between the sealant layer 16 and the barrier layer 13 can be further improved.

<Hydrogen sulfide adsorbent>
When the exterior materials 10 and 20 of the present embodiment are applied to all-solid-state battery applications, hydrogen sulfide may be generated by reaction with water depending on the type of all-solid-state electrolyte. Therefore, a material (hydrogen sulfide adsorbent) that decomposes or adsorbs hydrogen sulfide may be added to the exterior materials 10 and 20. The hydrogen sulfide adsorbent can be added to at least one of the first adhesive layer 12a, the second adhesive layer 12b, and the sealant layer 16, for example. The hydrogen sulfide adsorbent is added to at least one of the layers arranged inside the barrier layer 13 when the base material layer 11 side of the exterior materials 10 and 20 is the outside and the sealant layer 16 side is the inside. This is preferable because hydrogen sulfide generated inside the exterior materials 10 and 20 is easily adsorbed, and it is particularly preferable to add hydrogen sulfide to the sealant layer 16 because the effect is greater.

As hydrogen sulfide adsorbents, zinc oxide, amorphous metal silicate (mainly metal is copper and zinc), hydrate of zirconium and tantanoid element, tetravalent metal phosphate (especially metal is copper). , A mixture of zeolite and zinc ions, a mixture of zeolite, zinc oxide and copper (II) oxide, potassium permanganate, sodium permanganate, silver sulfate, silver acetate, aluminum oxide, iron hydroxide, isocyanate Examples thereof include compounds, aluminum silicate, potassium aluminum sulfate, zeolites, activated carbons, amine compounds, ionomers and the like. Among these, zinc oxide is preferable from the viewpoint of detoxifying hydrogen sulfide more easily and from the viewpoint of cost and handleability. The hydrogen sulfide adsorbent may be used alone or in combination of two or more.

The layer to which the hydrogen sulfide adsorbent is added may be a single layer or a plurality of layers. When adding a hydrogen sulfide adsorbent to the sealant layer 16, a high-concentration compounded product may be prepared in advance as a masterbatch, and then the masterbatch may be compounded with the resin of the sealant layer 16 so as to have an appropriate concentration. good. When blended in the first adhesive layer 12a or the second adhesive layer 12b, they may be blended directly in the coating liquid when they are formed by coating the adhesive, or they may be blended directly in the coating liquid, or when they are formed by extrusion or the like. A masterbatch may be prepared and blended in the same manner as in the sealant layer 16. As the resin for producing the master batch, thermoplastic resins such as polyolefin, polyamide, polyester, polycarbonate, polyphenylene ether, polyacetal, polystyrene, polyvinyl chloride, and polyvinyl acetate can be used.

In order to impart dispersibility, sealing property, heat resistance and other functions when adding a hydrogen sulfide adsorbent, for example, dispersants, antioxidants, slip agents, flame retardants, antiblocking agents, light stabilizers, dehydrators, etc. A tackifier, a crystal nucleating agent, a plasticizer and the like may be added.

The content of the hydrogen sulfide adsorbent is preferably 0.01 to 30% by mass, more preferably 0.1 to 20% by mass, based on the total solid content of the layer to be added. This is because if the content of the hydrogen sulfide adsorbent is less than 0.01% by mass, the effect of detoxifying hydrogen sulfide is small, and if it exceeds 30% by mass, the physical properties of the layer to be added tend to deteriorate.

[Manufacturing method of exterior materials]
Next, an example of a method for manufacturing the exterior material 10 shown in FIG. 1 will be described. The method for manufacturing the exterior material 10 is not limited to the following methods.

The method for manufacturing the exterior material 10 of the present embodiment includes a step of providing the corrosion prevention treatment layers 14a and 14b on the barrier layer 13 and a bonding of the base material layer 11 and the barrier layer 13 using the first adhesive layer 12a. A schematic configuration including a step, a step of further laminating the sealant layer 16 via the second adhesive layer 12b to prepare a laminate, and, if necessary, a step of aging the obtained laminate. Has been done.

(Step of laminating corrosion prevention treatment layers 14a and 14b on the barrier layer 13)
This step is a step of forming the corrosion prevention treatment layers 14a and 14b on the barrier layer 13. Examples of the method include a method of subjecting the barrier layer 13 to a degreasing treatment, a hydrothermal modification treatment, an anodization treatment, a chemical conversion treatment, and a method of applying a coating agent having corrosion prevention performance to the barrier layer 13.

When the corrosion prevention treatment layers 14a and 14b are multi-layered, for example, a coating liquid (coating agent) constituting the corrosion prevention treatment layer on the lower layer side (barrier layer 13 side) is applied to the barrier layer 13 and baked. After forming one layer, a coating liquid (coating agent) constituting the corrosion prevention treatment layer on the upper layer side may be applied to the first layer and baked to form the second layer.

The degreasing treatment may be performed by a spray method or a dipping method. The hydrothermal transformation treatment and the anodizing treatment may be carried out by the dipping method. As for the chemical conversion treatment, a dipping method, a spray method, a coating method and the like may be appropriately selected according to the type of chemical conversion treatment.

As a coating method for a coating agent having corrosion prevention performance, various methods such as gravure coating, reverse coating, roll coating, and bar coating can be used.

As described above, various treatments may be performed on either the double-sided surface or the single-sided surface of the metal foil, but in the case of the single-sided treatment, the treated surface is preferably applied to the side where the sealant layer 16 is laminated. If required, the surface of the base material layer 11 may also be subjected to the above treatment.

Moreover, neither the coating amount of the coating agent for forming the first layer and the second layer is preferably ^{0.005~0.200g / m 2, 0.010~0.100g / m} 2 is more preferable.

When drying cure is required, it can be carried out in the range of 60 to 300 ° C. as the base material temperature depending on the drying conditions of the corrosion prevention treatment layers 14a and 14b to be used.

(A process of bonding the base material layer 11 and the barrier layer 13)
This step is a step of bonding the barrier layer 13 provided with the corrosion prevention treatment layers 14a and 14b and the base material layer 11 via the first adhesive layer 12a. As a method of bonding, methods such as dry lamination, non-solvent lamination, and wet lamination are used, and both are bonded with the material constituting the first adhesive layer 12a described above. The first adhesive layer 12a is provided in a dry coating amount in ^{the range of 1 to 10 g / m 2} , more preferably in the range of ^{2 to 7 g / m 2.}

(Laminating step of the second adhesive layer 12b and the sealant layer 16)
This step is a step of adhering the sealant layer 16 to the second corrosion prevention treatment layer 14b side of the barrier layer 13 via the second adhesive layer 12b. Examples of the bonding method include a wet process and dry lamination.

In the case of a wet process, a solution or dispersion of the adhesive constituting the second adhesive layer 12b is applied onto the second corrosion prevention treatment layer 14b, and the solvent is blown off at a predetermined temperature to form a dry film. Alternatively, after drying the film, a baking process is performed as necessary. After that, the sealant layer 16 is laminated to manufacture the exterior material 10. Examples of the coating method include various coating methods exemplified above. The preferable dry coating amount of the second adhesive layer 12b is the same as that of the first adhesive layer 12a.

In this case, the sealant layer 16 can be manufactured by a melt extrusion molding machine using, for example, a resin composition for forming a sealant layer containing the above-mentioned constituent components of the sealant layer 16. In the melt extrusion molding machine, the processing speed can be set to 80 m / min or more from the viewpoint of productivity.

(Aging process)
This step is a step of aging (curing) the laminated body. By aging the laminate, adhesion between the barrier layer 13 / the second corrosion prevention treatment layer 14b / the second adhesive layer 12b / the sealant layer 16 can be promoted. The aging treatment can be carried out in the range of room temperature to 100 ° C. The aging time is, for example, 1 to 10 days.

In this way, the exterior material 10 of the present embodiment as shown in FIG. 1 can be manufactured.

Next, an example of the manufacturing method of the exterior material 20 shown in FIG. 2 will be described. The manufacturing method of the exterior material 20 is not limited to the following method.

The method for manufacturing the exterior material 20 of the present embodiment includes a step of providing the corrosion prevention treatment layers 14a and 14b on the barrier layer 13 and a bonding of the base material layer 11 and the barrier layer 13 using the first adhesive layer 12a. It is roughly configured including a step, a step of further laminating the sealant layer 16 to prepare a laminated body, and, if necessary, a step of heat-treating the obtained laminated body. The steps up to the step of bonding the base material layer 11 and the barrier layer 13 can be performed in the same manner as the above-described method for manufacturing the exterior material 10.

(Laminating process of sealant layer 16)
This step is a step of forming the sealant layer 16 on the second corrosion prevention treatment layer 14b formed in the previous step. Examples of the method include a method of laminating the sealant layer 16 using an extrusion laminating machine. In the formation of the sealant layer 16, for example, each component is blended so as to satisfy the constitution of the sealant layer 16 described above. The above-mentioned resin composition for forming a sealant layer is used for forming the sealant layer 16.

By this step, as shown in FIG. 2, the base material layer 11 / first adhesive layer 12a / first corrosion prevention treatment layer 14a / barrier layer 13 / second corrosion prevention treatment layer 14b / sealant layer 16 A laminated body in which each layer is laminated in order is obtained.

The sealant layer 16 may be laminated by directly extruding a material that has been dry-blended so as to have the above-mentioned material composition as a constituent component of the resin composition for forming the sealant layer by an extrusion laminating machine. Alternatively, the sealant layer 16 is extruded by an extrusion laminating machine using a granulated product that has been melt-blended using a melt-kneading device such as a single-screw extruder, a twin-screw extruder, or a brabender mixer in advance. It may be laminated with. The formation speed (processing speed) of the sealant layer 16 can be, for example, 80 m / min or more from the viewpoint of productivity.

(Heat treatment process)
This step is a step of heat-treating the laminated body. By heat-treating the laminate, the adhesion between the barrier layer 13 / the second corrosion prevention treatment layer 14b / the sealant layer 16 can be improved. As a method of heat treatment, it is preferable to treat at least at a temperature equal to or higher than the melting point of the sealant layer 16.

In this way, the exterior material 20 of the present embodiment as shown in FIG. 2 can be manufactured.

Although the preferred embodiments of the exterior material for the power storage device of the present disclosure have been described in detail above, the present disclosure is not limited to such specific embodiments, and the present disclosure described within the scope of the claims. Various modifications and changes are possible within the scope of the abstract.

The exterior material for a power storage device of the present disclosure is suitable as an exterior material for a power storage device such as a secondary battery such as a lithium ion battery, a nickel hydrogen battery, and a lead storage battery, and an electrochemical capacitor such as an electric double layer capacitor. Can be used. Above all, the exterior material for a power storage device of the present disclosure can maintain excellent heat-sealing properties even when used in a high-temperature environment after heat-sealing, and therefore, a solid electrolyte that is expected to be used in such an environment. It is suitable as an exterior material for an all-solid-state battery using.

[Power storage device]
FIG. 3 is a perspective view showing an embodiment of a power storage device manufactured by using the above-mentioned exterior material. As shown in FIG. 3, the power storage device 50 includes a battery element (power storage device main body) 52 including an electrode, and two metal terminals (leads) extending from the electrode and extracting a current from the battery element 52 to the outside. , Current take-out terminal) 53, and an exterior material 10 that includes the battery element 52 in an airtight state. The exterior material 10 is the exterior material 10 according to the present embodiment described above, and is used as a container for accommodating the battery element 52. In the exterior material 10, the base material layer 11 is the outermost layer, and the sealant layer 16 is the innermost layer. That is, in the exterior material 10, one laminated film is folded in half and the peripheral edge portion is heat-sealed so that the base material layer 11 is on the outer side of the power storage device 50 and the sealant layer 16 is on the inner side of the power storage device 50. By doing so, or by stacking two laminated films and heat-sealing the peripheral edge portion, the battery element 52 is included inside. The metal terminal 53 is sandwiched and sealed by an exterior material 10 that forms a container with the sealant layer 16 inside. The metal terminal 53 may be sandwiched by the exterior material 10 via the tab sealant. In the power storage device 50, the exterior material 20 may be used instead of the exterior material 10.

The battery element 52 is formed by interposing an electrolyte between the positive electrode and the negative electrode. The metal terminal 53 is a part of the current collector taken out from the exterior material 10, and is made of a metal foil such as a copper foil or an aluminum foil.

The power storage device 50 of the present embodiment may be an all-solid-state battery. In this case, a solid electrolyte such as a sulfide-based solid electrolyte is used as the electrolyte of the battery element 52. Since the power storage device 50 of the present embodiment uses the exterior material 10 of the present embodiment, excellent heat seal strength can be ensured in a high temperature environment (for example, 150 ° C.), and the room temperature after being exposed to the high temperature environment. Excellent heat seal strength in the environment can be ensured.

Hereinafter, the present disclosure will be described in more detail based on Examples, but the present disclosure is not limited to the following Examples.

[Material used]
The materials used in Examples and Comparative Examples are shown below.

<Base layer (thickness 25 μm)>
A polyethylene terephthalate film having a corona treatment on one surface was used.

<First adhesive layer (thickness 4 μm)>
A polyurethane-based adhesive (manufactured by Toyo Ink Co., Ltd.) containing an adduct-based curing agent for tolylene diisocyanate was used as a polyester polyol-based main agent.

<First corrosion prevention treatment layer (base material layer side) and second corrosion prevention treatment layer (sealant layer side)>
(CL-1): Distilled water was used as a solvent, and "sodium polyphosphate stabilized cerium oxide sol" adjusted to a solid content concentration of 10% by mass was used. The sodium polyphosphate stabilized cerium oxide sol was obtained by blending 10 parts by mass of Na salt of phosphoric acid with 100 parts by mass of cerium oxide.
(CL-2): 90% by mass of "polyallylamine (manufactured by Nitto Boseki)" adjusted to a solid content concentration of 5% by mass using distilled water as a solvent, and "polyglycerol polyglycidyl ether (manufactured by Nagase ChemteX)". A composition consisting of 10% by mass was used.
(CL-3): Chromium fluoride (CrF3) was finally dried with respect to a water-soluble phenol resin (manufactured by Sumitomo Bakelite Co., Ltd.) adjusted to have a solid content concentration of 1% by mass using an aqueous phosphoric acid solution having a concentration of 1% by mass as a solvent. The concentration was adjusted so that the amount of Cr present in the film was 10 mg / m ^2, and a chemical treatment agent was used.

<Barrier layer (thickness: 40 μm)>
A soft aluminum foil (manufactured by Toyo Aluminum Co., Ltd., “8079 material”) that had been annealed and degreased was used.

<Second adhesive layer (thickness 3 μm)>
Epoxy-based mixture of 100 parts by mass of epoxy resin (manufactured by Adeka Corporation, trade name: EP4100) and 25 parts by mass of polyamide amine-based curing agent (manufactured by Adeka Corporation, trade name: EH4602) diluted with ethyl acetate to a solid content of 30% by mass. An adhesive was used.

<Sealant layer (thickness: 80 μm)>
The first resin and the second resin shown in Table 1 were prepared. As the first resin and the second resin, a resin composition for forming a sealant layer was used by melt-blending them with a twin-screw kneader in advance. Tables 2 to 6 show the composition of the resin composition for forming the sealant layer (the resin used and the blending amount thereof). The unit "%" of the blending amount in the table means the unit "mass%" based on the mass when the total amount of the first resin and the second resin is used as a reference (100% by mass). Further, the modified polyolefin is one modified with an acid anhydride shown in the column of the description name, or one having a polar group shown in the same column.

<Hydrogen sulfide adsorbent>
In some examples and comparative examples, zinc oxide (manufactured by Sakai Chemical Industry Co., Ltd.) as a hydrogen sulfide adsorbent was added to the sealant layer or the second adhesive layer. The presence or absence of addition is shown in Tables 2 to 6. When added to the sealant layer, the amount added was 3 parts by mass with respect to 100 parts by mass of the total amount of the first resin and the second resin. When the sealant layer was made into multiple layers, it was added to both layers in the above-mentioned addition amount. When added to the second adhesive layer, the amount added was 3 parts by mass with respect to 100 parts by mass of the total amount of the epoxy resin and the curing agent. The hydrogen sulfide adsorbent was used by mixing with the materials constituting each layer.

[Making exterior materials]
(Examples 1 to 3)
The barrier layer was attached to the base material layer by a dry laminating method using a polyurethane-based adhesive (first adhesive layer). To laminate the barrier layer and the base material layer, a polyurethane adhesive is applied on one surface of the barrier layer so that the thickness after curing is 4 μm, dried at 80 ° C. for 1 minute, and then the base material is used. This was done by laminating with a layer and aging at 60 ° C. for 5 days.

Next, the side of the barrier layer opposite to the base material layer was attached to the sealant layer by a dry laminating method using an epoxy adhesive (second adhesive layer). To laminate the barrier layer and the sealant layer, apply an epoxy adhesive on the surface of the barrier layer opposite to the base material layer so that the thickness after curing is 3 μm, and dry at 80 ° C. for 1 minute. After that, it was laminated with a sealant layer and aged at 120 ° C. for 3 hours. As the sealant layer, the resin composition for forming the sealant layer shown in Table 2 was previously formed as a cast film. By the above method, an exterior material (a laminate of a base material layer / a first adhesive layer / a barrier layer / a second adhesive layer / a sealant layer) was produced.

(Examples 4 to 14)
First, the first and second corrosion prevention treatment layers were provided on the barrier layer by the following procedure. That is, (CL-1) was applied to both surfaces of the barrier layer by a ^{microgravure coat so that the dry application amount was 70 mg / m 2,} and the drying unit was baked at 200 ° C. Next, (CL-2) was applied onto the obtained layer by a ^{microgravure coat so as to have a dry coating amount of 20 mg / m 2} , whereby a composite composed of (CL-1) and (CL-2) was applied. The layers were formed as first and second corrosion protection treatment layers. This composite layer exhibits corrosion prevention performance by combining two types of (CL-1) and (CL-2).

Next, the first corrosion prevention treatment layer side of the barrier layer provided with the first and second corrosion prevention treatment layers is subjected to a dry laminating method, and a base material is used with a polyurethane adhesive (first adhesive layer). I stuck it on the layer. To laminate the barrier layer and the base material layer, a polyurethane adhesive is applied on the surface of the barrier layer on the side of the first corrosion prevention treatment layer so that the thickness after curing is 4 μm, and the thickness is 1 at 80 ° C. After drying for a minute, it was laminated with a substrate layer and aged at 60 ° C. for 5 days.

Next, the sealant layer is provided on the second corrosion prevention treatment layer side of the barrier layer provided with the first and second corrosion prevention treatment layers by a dry laminating method using an epoxy adhesive (second adhesive layer). I pasted it on. To laminate the barrier layer and the sealant layer, apply an epoxy adhesive on the surface of the barrier layer opposite to the base material layer so that the thickness after curing is 3 μm, and dry at 80 ° C. for 1 minute. After that, it was laminated with a sealant layer and aged at 120 ° C. for 3 hours. As the sealant layer, the resin composition for forming the sealant layer shown in Table 2 was previously formed as a cast film. By the above method, a laminate of exterior materials (base material layer / first adhesive layer / first corrosion prevention treatment layer / barrier layer / second corrosion prevention treatment layer / second adhesive layer / sealant layer). ) Was prepared. The hydrogen sulfide adsorbent was added to the second adhesive layer in Example 12 and to the sealant layer in the other examples.

(Example 15)
The exterior material (base material layer / first adhesive layer / barrier layer / second adhesive layer / sealant layer laminate) is provided in the same manner as in Example 11 except that the corrosion prevention treatment layer is not provided. Made.

(Example 16)
The exterior material (base material layer / first adhesive layer / first corrosion prevention treatment layer / barrier layer / second) was the same as in Example 11 except that the hydrogen sulfide adsorbent was not added to the sealant layer. (Corrosion prevention treatment layer / second adhesive layer / sealant layer laminate) was prepared.

(Examples 17 to 23)
The exterior material (base material layer / first adhesive layer / first corrosion prevention treatment layer) is the same as in Example 11 except that the composition of the resin composition for forming the sealant layer is changed as shown in Table 3. / Barrier layer / Second corrosion prevention treatment layer / Second adhesive layer / Sealant layer laminate) was prepared.

(Example 24)
The first and second corrosion prevention treatment layers were provided by the following procedure. That is, (CL-3) was applied to both surfaces of the barrier layer by a ^{microgravure coat so that the dry application amount was 30 mg / m 2,} and the drying unit was baked at 200 ° C. Next, (CL-2) was applied onto the obtained layer by a ^{microgravure coat so as to have a dry coating amount of 20 mg / m 2} , whereby a composite composed of (CL-3) and (CL-2) was applied. The layers were formed as first and second corrosion protection treatment layers. This composite layer exhibits corrosion prevention performance by combining two types of (CL-3) and (CL-2). The exterior material (base material layer / first adhesive layer / first Corrosion prevention treatment layer / barrier layer / second corrosion prevention treatment layer / second adhesive layer / sealant layer laminate) was prepared.

(Examples 25 to 27)
In the same manner as in Example 11, the barrier layer provided with the first and second corrosion prevention treatment layers and the base material layer were laminated with a polyurethane adhesive (first adhesive layer). Next, this was set in the unwinding portion of the extrusion laminating machine, and the sealant layer (thickness 80 μm) was extruded and laminated on the second corrosion prevention treatment layer under the processing conditions of 270 ° C. and 100 m / min. The sealant layer was prepared in advance using a twin-screw extruder to prepare a compound of various materials, and was used for the extrusion lamination after undergoing a water cooling and pelletizing process. For the formation of the sealant layer, the resin composition for forming the sealant layer shown in Table 4 was used.

The laminate thus obtained is heat-treated so that the maximum temperature of the laminate reaches 220 ° C., and the exterior material (base material layer / first adhesive layer / first corrosion prevention) is subjected to heat treatment. A laminated body of a treated layer / a barrier layer / a second corrosion prevention treated layer / a sealant layer) was prepared.

(Examples 28 to 30 and 33)
The exterior material (base material layer / first adhesive layer / first corrosion prevention treatment layer) is the same as in Example 11 except that the composition of the resin composition for forming the sealant layer is changed as shown in Table 4. / Barrier layer / Second corrosion prevention treatment layer / Second adhesive layer / Sealant layer laminate) was prepared.

(Examples 31 to 32 and 34)
The exterior material (base material layer / first adhesive layer / first corrosion prevention treatment layer) is the same as in Example 26 except that the composition of the resin composition for forming the sealant layer is changed as shown in Table 4. / Barrier layer / Second corrosion prevention treatment layer / Sealant layer laminate) was prepared.

(Examples 35 and 38-39)
In the same manner as in Example 11, the barrier layer provided with the first and second corrosion prevention treatment layers and the base material layer were laminated with a polyurethane adhesive (first adhesive layer). Next, the sealant layer is provided on the second corrosion prevention treatment layer side of the barrier layer provided with the first and second corrosion prevention treatment layers by a dry laminating method using an epoxy adhesive (second adhesive layer). I pasted it on. To laminate the barrier layer and the sealant layer, apply an epoxy adhesive on the surface of the barrier layer opposite to the base material layer so that the thickness after curing is 3 μm, and dry at 80 ° C. for 1 minute. After that, it was laminated with a sealant layer and aged at 120 ° C. for 3 hours. As the sealant layer, the resin composition for forming the sealant layer for the barrier layer side and the resin composition for forming the sealant layer for the innermost layer side shown in Table 5 are used in advance to form a multilayer cast film (thickness of each layer). : 40 μm) was used as a film. By the above method, the exterior material (base material layer / first adhesive layer / first corrosion prevention treatment layer / barrier layer / second corrosion prevention treatment layer / second adhesive layer / sealant layer (barrier layer) A laminated body of the side sealant layer and the innermost layer side sealant layer) was prepared. The hydrogen sulfide adsorbent was added to both of the two sealant layers.

(Examples 36 to 37 and 40)
In the same manner as in Example 11, the barrier layer provided with the first and second corrosion prevention treatment layers and the base material layer were laminated with a polyurethane adhesive (first adhesive layer). Next, this is set in the unwinding portion of the extrusion laminating machine and co-extruded onto the second corrosion prevention treatment layer at 270 ° C. and 100 m / min processing conditions to obtain two sealant layers (both layers have a thickness). 40 μm) was laminated. The sealant layer was prepared in advance using a twin-screw extruder to prepare a compound of various materials, and was used for the extrusion lamination after undergoing a water cooling and pelletizing process. For the formation of the sealant layer, the sealant layer forming resin composition for the barrier layer side and the sealant layer forming resin composition for the innermost layer side shown in Table 5 were used.

The laminate thus obtained is heat-treated so that the maximum temperature of the laminate reaches 220 ° C., and the exterior material (base material layer / first adhesive layer / first corrosion prevention) is subjected to heat treatment. A laminated body of a treatment layer / barrier layer / second corrosion prevention treatment layer / sealant layer (barrier layer side sealant layer and innermost layer side sealant layer) was prepared. The hydrogen sulfide adsorbent was added to both of the two sealant layers.

(Examples 41 to 42)
The exterior material (base material layer / first adhesive layer / first corrosion prevention treatment layer) is the same as in Example 11 except that the composition of the resin composition for forming the sealant layer is changed as shown in Table 5. / Barrier layer / Second corrosion prevention treatment layer / Second adhesive layer / Sealant layer laminate) was prepared.

(Comparative Examples 1 to 2, 4 and 6)
The exterior material (base material layer / first adhesive layer / first corrosion prevention treatment layer) is the same as in Example 11 except that the composition of the resin composition for forming the sealant layer is changed as shown in Table 6. / Barrier layer / Second corrosion prevention treatment layer / Second adhesive layer / Sealant layer laminate) was prepared.

(Comparative Examples 3 and 5)
The exterior material (base material layer / first adhesive layer / first corrosion prevention treatment layer) is the same as in Example 26 except that the composition of the resin composition for forming the sealant layer is changed as shown in Table 6. / Barrier layer / Second corrosion prevention treatment layer / Sealant layer laminate) was prepared.

[Measurement of crystallinity after heat sealing]
Two exterior materials using polyester or polyamide as the second resin were prepared, laminated so that the sealant layers faced each other, and heat-sealed under the conditions of 260 ° C., 0.5 MPa, and 3 seconds. Then, after cooling to 25 ° C., the crystallinity of polyester and polyamide in the sealant layer was measured. The crystallinity was calculated from the area ratio of crystal part peak / (amorphous part peak + crystal part peak) using IR.

[Measurement of room temperature heat seal strength]
A sample obtained by cutting the exterior material into 60 mm × 120 mm was folded in two, and one side was heat-sealed with a seal bar having a width of 10 mm at 220 ° C., 0.5 MPa, and 3 seconds. The exterior material after heat sealing was aged for 60 minutes in an environment of 150 ° C., and then cooled to room temperature. The heat-sealed portion was cut to a width of 15 mm (see FIG. 4), and the seal strength (T-shaped peeling strength) was measured using a testing machine (manufactured by INSTRON). The test was carried out according to JIS K6854 at 23 ° C. and a 50% RH atmosphere at a peeling speed of 50 mm / min. Based on the measured seal strength (burst strength) value, evaluation was made based on the following criteria. If the evaluation result is C or higher, it is passed.
A: Seal strength is 40N / 15mm or more B: Seal strength is 30N / 15mm or more and less than 40N / 15mm C: Seal strength is 25N / 15mm or more and less than 30N / 15mm D: Seal strength is less than 25N / 15mm

Further, the reduction rate of the seal strength was calculated based on the following formula from the comparison of the seal strength before and after 150 ° C. aging (hereinafter, sometimes referred to as “150 ° C. AG”).
Rate of decrease (%) = {(seal strength before 150 ° C.AG-seal strength after 150 ° C. AG) / seal strength before 150 ° C. AG} x 100

[Measurement of high temperature heat seal strength]
A sample obtained by cutting the exterior material into 60 mm × 120 mm was folded in two, and one side was heat-sealed with a seal bar having a width of 10 mm at 220 ° C., 0.5 MPa, and 3 seconds. Then, the heat-sealed portion is cut to a width of 15 mm (see FIG. 4), allowed to stand for 5 minutes in an environment of 150 ° C., and then sealed in a peeling speed of 50 mm / min in an environment of 150 ° C. (T). The shape peeling strength) was measured using a testing machine (manufactured by INSTRON). Based on the measured seal strength (burst strength) value, evaluation was made based on the following criteria. If the evaluation result is C or higher, it is passed.
A: Seal strength is 35N / 15mm or more B: Seal strength is 30N / 15mm or more and less than 35N / 15mm C: Seal strength is 20N / 15mm or more and less than 30N / 15mm D: Seal strength is less than 20N / 15mm

[Measurement of room temperature heat-sealing strength after H 2 _S exposure]
A sample obtained by cutting the exterior material into 60 mm × 120 mm was folded in two, and one side was heat-sealed with a seal bar having a width of 10 mm at 220 ° C., 0.5 MPa, and 3 seconds. Then, the heat-sealed portion was cut to a width of 15 mm (see FIG. 4), and allowed to stand at room temperature for 72 hours in an environment with a hydrogen sulfide concentration of 20 mass ppm. Then, after allowing to stand for 5 minutes in a room temperature environment, the sealing strength (T-shaped peeling strength) of the heat-sealed portion was measured using a testing machine (manufactured by INSTRON). The test was carried out according to JIS K6854 at 23 ° C. and a 50% RH atmosphere at a peeling speed of 50 mm / min. Based on the measured seal strength (burst strength) value, evaluation was made based on the following criteria.
A: Seal strength is 50N / 15mm or more B: Seal strength is 40N / 15mm or more and less than 50N / 15mm C: Seal strength is 35N / 15mm or more and less than 50N / 15mm D: Seal strength is less than 35N / 15mm

Measurement of high-temperature heat-sealing strength after H 2 _S exposure]
A sample obtained by cutting the exterior material into 60 mm × 120 mm was folded in two, and one side was heat-sealed with a seal bar having a width of 10 mm at 220 ° C., 0.5 MPa, and 3 seconds. Then, the heat-sealed portion was cut to a width of 15 mm (see FIG. 4), and allowed to stand at room temperature for 72 hours in an environment with a hydrogen sulfide concentration of 20 mass ppm. Then, after allowing to stand for 5 minutes in an environment of 150 ° C., the sealing strength (T-shaped peeling strength) under the condition of a peeling speed of 50 mm / min in an environment of 150 ° C. was measured using a testing machine (manufactured by INSTRON). It was measured. Based on the measured seal strength (burst strength) value, evaluation was made based on the following criteria.
A: Burst strength is 35N / 15mm or more B: Burst strength is 30N / 15mm or more and less than 35N / 15mm C: Burst strength is 20N / 15mm or more and less than 30N / 15mm D: Burst strength is less than 20N / 15mm

According to the present disclosure, excellent heat seal strength can be ensured in a high temperature environment (for example, 150 ° C.), and a decrease in heat seal strength in a room temperature environment after use in a high temperature environment (for example, 150 ° C.) is suppressed. An exterior material for a power storage device that can be used and a power storage device using the same are provided.

10, 20 ... Exterior material for power storage device, 11 ... Base material layer, 12a ... First adhesive layer, 12b ... Second adhesive layer, 13 ... Barrier layer, 14a ... First corrosion prevention treatment layer, 14b ... Second corrosion prevention treatment layer, 16 ... Sealant layer, 50 ... Power storage device, 52 ... Battery element, 53 ... Metal terminal.

Claims (9)

An exterior material for a power storage device including at least a base material layer, a barrier layer, and a sealant layer in this order.
An exterior material for a power storage device, wherein the sealant layer contains a polyolefin as a first resin and at least one resin selected from the group consisting of polyester, polyamide, polycarbonate and polyphenylene ether as a second resin. The exterior material for a power storage device according to claim 1, wherein the first resin contains a modified polyolefin having a polar group capable of reacting with the second resin. The exterior material for a power storage device according to claim 2, wherein the modified polyolefin is a polyolefin modified with maleic anhydride. The sealant layer comprises the polyester and / or the polyamide
The crystallinity of the polyester and / or the polyamide after heat-sealing the sealant layer at 260 ° C., 0.5 MPa for 3 seconds and cooling to 25 ° C. is 10% or more and less than 70%. The exterior material for a power storage device according to any one of claims 1 to 3. The exterior material for a power storage device according to any one of claims 1 to 4, wherein a corrosion prevention treatment layer is provided on one or both surfaces of the barrier layer. When the base material layer side of the exterior material for a power storage device is on the outside and the sealant layer side is on the inside, at least one layer of the layers arranged inside the barrier layer contains a hydrogen sulfide adsorbent. The exterior material for a power storage device according to any one of claims 1 to 5. The exterior material for a power storage device according to any one of claims 1 to 6, which is for an all-solid-state battery. The main body of the power storage device and
The current take-out terminal extending from the power storage device main body and
The exterior material for a power storage device according to any one of claims 1 to 7, which sandwiches the current take-out terminal and accommodates the power storage device main body.
A power storage device equipped with. The power storage device according to claim 8, which is an all-solid-state battery.

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