JP5782889B2 - Battery container and lithium ion battery including the same - Google Patents

Description

  The present invention relates to a battery container composed of a laminate having a sealant layer and a lithium ion battery including the same.

  Conventionally, lead-acid batteries and nickel-metal hydride batteries have been widely used as secondary batteries. However, with the miniaturization of portable devices such as mobile phones and notebook computers, lithium that can be made lighter with higher energy density. Many ion secondary batteries are used. In recent years, in particular, laminated lithium-ion batteries, which have advantages in freedom of shape, thickness reduction, weight reduction, and heat dissipation, are different from the can type that has been used as a conventional packaging material for batteries. It is actively developed as a secondary battery.

  Laminate type lithium ion battery container has a three-side seal, four-side seal, pillow pouch type, and battery case material, in which a battery case is made to open on one side and a lithium ion battery is stored inside There is an embossed type in which a recess is formed by press molding and a lithium ion battery is accommodated in the recess. In any container, the container edge is sealed by thermal bonding of the sealant layer.

By the way, lithium salt such as LiPF ₆ and LiBF ₄ is used as the electrolyte for the contents of the lithium ion battery, but these salts are hydrolyzed by reacting with moisture to generate hydrofluoric acid. Therefore, when water permeates into the lithium ion battery, hydrofluoric acid is generated in the battery, and there are problems such as corrosion of the metal surface in the exterior material and a decrease in laminate strength between the layers of the multilayer film.

  Therefore, the exterior material used for the laminate-type lithium ion battery container uses, for example, an aluminum foil for a part of a multilayer film in which a base material layer, an adhesive layer, an aluminum foil layer, an adhesive resin layer, and a sealant layer are sequentially laminated. Thus, moisture intrusion from the surface of the multilayer film is blocked. However, since the end surfaces of the adhesive resin layer and the sealant layer are present on the seal end surface of the battery container edge, it is difficult to completely block the ingress of moisture into the battery container.

  In addition, since a tab lead composed of an electrode tab and a tab sealant for taking out current from the electrode is inserted between the laminates, there is a concern that the end surface of the sealant layer is particularly large at the portion where the tab lead is provided and moisture permeation is increased. was there. Further, when the sealing conditions are inappropriate, there is a concern about leakage of the electrolyte from between the tab lead and the sealant layer.

  In view of this, studies have been made to suppress the intrusion of moisture from the end face of the heat seal portion. For example, Patent Document 1 describes a battery container in which moisture permeability is suppressed by thinning a sealant layer in the heat seal portion. However, thinning of the heat seal portion by compression promotes the formation of poly balls (resin leakage) outside the seal edge and causes bag breakage. In addition, there is a problem that the seal strength is reduced by making the sealant layer thin.

  Further, Patent Document 2 discloses a heat sealing method that secures the infiltration of moisture from the outside and the sealing strength against the internal pressure of the container by changing the thickness of the sealant layer at the center of the seal width, and the manufacturing method thereby. A battery container is described. However, in this method, the seal strength of the outer portion where the sealant layer is thin is lowered, and there is a concern that when some external force is applied to the outside of the seal, the seal peeling from the outside tends to occur.

JP 2001-176466 A JP 2001-199413 A

  Therefore, in view of the problems of the prior art, the present invention has excellent reliability such as suppression of cracks due to external impact, prevention of bag breakage due to increase in internal pressure, suppression of moisture permeation, and improvement of seal strength. It aims at providing the container for batteries by a laminated body.

According to the first aspect of the present invention, the sealant layer side of a laminate formed by sequentially laminating at least an aluminum foil layer, an adhesive resin layer, and a sealant layer on one side of the substrate is opposed, and the periphery of the edge is heat-sealed. The heat seal shape includes a knurled structure (network structure) having a thin seal portion and a thick seal portion, and the thin seal portion The total thickness of the adhesive resin layer and sealant layer occupying is 70% or less of the total thickness of the adhesive resin layer and sealant layer occupying the thick seal portion, and the unit width of the thin seal portion is thick. and 60% or less than 20% of the unit width of the sealing portion, the heat sealed area knurled structure is the cell container, characterized in that 80% or less than 20% of the total heat seal width

According to a second aspect of the invention, a lithium ion battery, characterized by comprising a battery container according to claim 1.

  According to the present invention, the formation of poly beads in the battery container during heat sealing and the occurrence of cracks are not only high in impact resistance, but also excellent in suppression of moisture permeation, insulation and electrolyte solution. It is possible to provide a battery container that is resistant to leakage and excellent in long-term reliability.

It is sectional drawing which showed an example of embodiment of the laminated body which concerns on the battery container of this invention. It is the schematic diagram which showed an example of the laminated body sealing method which concerns on the battery container of this invention. It is sectional drawing which showed an example of the laminated body sealing method which concerns on the battery container of this invention.

  Hereinafter, an embodiment of the method for forming a battery container and the production of the battery according to the present invention will be described in detail using a lithium ion battery as an example.

  As shown in FIG. 1, the laminate 1 according to the battery container of the present embodiment has an adhesive layer 10, an aluminum foil layer 15, an adhesive resin layer 25, and a sealant layer 30 sequentially on one surface of the substrate 3. Are stacked.

  A positive electrode, a separator, and a negative electrode are accommodated in an embossed interior of the laminate 1, a tab lead is led out from the inside of the container, and then the laminate 1 is overlapped so that the sealant layer 30 faces. Heat seal to leave Thereafter, an electrolytic solution is injected from the opened one side, and after completion of the injection, the opening is heat-sealed in a vacuum environment, and the inside is sealed to produce a lithium ion battery.

<Heat sealing process>
The sealant layers 30 of the laminate 1 are stacked so as to face each other, and the seal portion is heat-sealed in a knurled shape (network structure). At this time, as shown in FIG. 2, by heat-sealing in a knurled shape, a thick portion and a thin portion of the adhesive resin layer 25 and the sealant layer 30 can be formed. The presence of a portion where the total thickness of the adhesive resin layer and the sealant layer is thin (thin seal portion 40) makes it possible to suppress moisture permeation. However, when the thin seal portion 40 is provided, the sealant resin in that portion moves to the outside of the thin seal portion, and when this amount increases, poly balls are formed and the bag is broken. Therefore, the thick seal portion 50 is provided as a place for receiving the excess sealant resin coming out of the thin seal portion. Further, since the thick seal portion 50 has a sufficiently large total thickness of the adhesive resin layer 25 and the sealant layer 30, a strong heat seal strength can be exhibited. That is, by forming a thin seal portion and a thick seal portion in a knurl shape, a thin seal portion 40 that can suppress moisture permeation and a thick seal portion 50 that can absorb excess resin and maintain strong heat seal strength. It is possible to provide a battery container with high reliability that is the object of the present invention. At this time, the total thickness of the adhesive resin layer 25 and the sealant layer 30 in the thin seal part is preferably 70% or less of the total thickness of the adhesive resin layer 25 and the sealant layer 30 in the thick seal part. If the total thickness of the thin seal portion exceeds 70% of the total thickness of the thick seal portion, the effect of each seal portion even when heat-sealed in a knurl shape, that is, suppression of moisture permeation and improvement of heat seal strength Can't get.

  The thickness of the thin seal portion in the region heat-sealed in a knurl shape is preferably 30 μm or more and 100 μm. This is because when the total thickness of the adhesive resin layer and the sealant layer in the thin seal portion is less than 30 μm, the effect of suppressing moisture permeation increases, but on the other hand, the seal strength tends to be weak, and the aluminum foils are closer together. This is because the insulating property is lowered. In particular, care must be taken so that the distance between the electrode tab and the aluminum foil does not become thinner than 30 μm. Further, when the total thickness of the adhesive resin layer and the sealant layer in the thin seal portion is thicker than 100 μm, the moisture permeation suppressing effect becomes insufficient, which is not preferable.

  Further, in the thin seal portion 40 and the thick seal portion 50 that are alternately present in the heat-sealed portions (network structure portion) in the knurled shape, the unit width of the thin seal portion 40 is 20% to the unit width of the thick seal portion 50. 60% is preferable. When the unit width of the thin seal portion 40 is less than 20% of the unit width of the thick seal portion 50, the effect of suppressing moisture permeation is insufficient. If the unit width of the thin seal portion 40 exceeds 60% of the unit width of the thick seal portion 50, the sealant resin flowing out from the thin seal portion cannot be sufficiently absorbed by the thick seal portion, and the seal thickness becomes non-uniform. In addition, there is a problem that the sealant resin is extruded to the seal end portion and leads to the formation of poly balls. The unit width means the width of each of the thin seal portion and the thick seal portion in the cross section on the diagonal line of the mesh structure portion.

Moreover, the outermost part and the innermost part of the heat seal region are preferably not normal knurled (network structure) heat seal but normal heat seal. This is to prevent the sealant resin from being pushed out from the thin seal portion to the seal end portion to form poly balls. In addition, the absence of a thin seal portion at the end portion can provide a stronger heat seal strength. For this reason, it is preferable that the knurled (network structure) heat seal width is 20% to 80% symmetrically with respect to the total heat seal width. When the knurled heat seal width is less than 20% of the total heat seal width, it becomes insufficient to suppress moisture permeation. On the other hand, if it exceeds 80%, there is a problem that the heat seal strength is not stable due to the presence of a thin seal portion at the seal end. In addition, the normal heat seal referred to in the present invention is a heat seal in which the sealing surface is formed as a flat surface unlike the knurled shape.

  Further, as described above, when the knurled heat seal region is not provided in the innermost and outermost portions of the heat seal portion in the present invention, the total thickness of the adhesive resin layer and the sealant layer after the heat seal in the normal seal region Is preferably in the range of 60% to 90% of the total thickness before heat sealing. If this is too thick, sufficient seal strength will not be obtained. If it is too thin, it will be effective in suppressing moisture permeation, but it will promote the formation of poly balls (resin leakage) outside the seal end and cause bag breakage. It is because it becomes. Moreover, it is because there exists a problem that seal strength falls by making a sealant layer thin film extremely. In particular, the innermost part and the outermost part are easily affected by internal pressure and external force, and therefore management of the seal thickness is important for obtaining a stable seal strength. This provides a battery container capable of suppressing the formation of poly beads in the battery container during heat sealing, the generation of cracks, the suppression of moisture permeation from the outside, and the sealing strength against the internal pressure of the container. Is possible.

  For example, by providing a knurled portion on the upper or lower or both seal bars in a heat sealing device, a thick portion and a thin portion of the adhesive resin layer and the sealant layer can be formed in a knurled shape. Is possible. Note that when the knurled shape is provided on the upper and lower seal bars, care should be taken because it is preferable that the positions of the thin seal portion and the thick seal portion are not shifted.

  The form of the battery container produced by such a heat sealing method is not limited to a specific shape. For example, a three-sided seal, a four-sided seal, a pillow pouch type bag-like container, and a battery exterior material are used. It may be a concave container such as an embossed type in which a recess is formed by press molding and a battery is accommodated in the recess.

<Base material>
The base material 3 according to the present invention is provided for the purpose of imparting heat resistance in a sealing process during the production of a lithium ion battery, and for preventing pinholes that may occur during processing and distribution, and uses an insulating polymer material. be able to. As such a polymer material, for example, a stretched or unstretched film such as a polyester film, a polyamide film, or a polypropylene film, or a single layer or a laminated film of two or more layers can be used. A stretched polyamide film and a stretched polyester film are preferable in terms of improving pinhole resistance and insulation. Moreover, the thickness of the base material 3 is preferably 6 to 40 μm, more preferably 10 to 25 μm in consideration of pinhole resistance and workability. Furthermore, the base material 3 may mix | blend or apply | coat additives, such as a slip agent and an antiblocking agent, for example.

<Adhesive layer>
As the adhesive layer 10, a two-component curable polyurethane adhesive using a polyester polyol, a polyether polyol or an acrylic polyol as a main agent and an aromatic or aliphatic isocyanate as a curing agent is preferable. By performing the aging after coating at 40 ° C. for 4 days or longer, the reaction between the OH group and the NCO group proceeds and the films on both sides are firmly bonded. Generally, the molar ratio [NCO / OH] of the curing agent NCO to OH of the main agent is preferably about 1 to 10, more preferably 2 to 5. In addition, the thickness of the adhesive layer 10 is preferably 1 to 10 μm, more preferably 3 to 7 μm in consideration of adhesive strength, followability, workability, and the like.

<Aluminum foil layer>
As a material of the aluminum foil layer 15, a general soft aluminum foil can be used, but it is desirable to use an aluminum foil containing iron for the purpose of imparting further pinhole resistance and extensibility during molding. 0.1-9.0 mass% is preferable in 100 mass% of aluminum foil, and, as for content of iron, 0.5-2.0 mass% is more preferable. If the lower limit value of the iron content is less than the above value, sufficient pinhole resistance and ductility cannot be imparted. On the other hand, if the upper limit value is more than the above value, flexibility is impaired. The thickness of the aluminum foil layer 15 is preferably 9 to 200 μm and more preferably 15 to 100 μm in view of barrier properties, pinhole resistance and workability.

<Corrosion prevention treatment layer>
The corrosion prevention treatment layer 20 is provided for the purpose of preventing the corrosion of the aluminum foil layer 15. Here, examples of the layer intended to prevent corrosion of aluminum include a degreasing treatment, a hydrothermal alteration treatment, an anodizing treatment, a chemical conversion treatment, or a combination of these treatments. Degreasing treatment includes acid degreasing or alkaline degreasing, and acid degreasing includes a method using an inorganic acid such as sulfuric acid, nitric acid, hydrochloric acid, hydrofluoric acid alone or a mixture thereof. In addition, by using an acid degreasing agent in which a fluorine-containing compound such as ammonium monofluoride is dissolved in the above-mentioned inorganic acid as acid degreasing, not only the degreasing effect of aluminum but also passive aluminum fluoride is formed. This is effective in terms of resistance to hydrofluoric acid. Examples of the alkaline degreasing include sodium hydroxide. Examples of the hydrothermal modification treatment include boehmite treatment obtained by immersing aluminum foil in boiling water to which triethanolamine is added. Anodizing may be anodized. Examples of the chemical conversion 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 conversion treatments composed of these mixed phases. This corrosion prevention treatment layer may be a single layer or a multilayer. These hydrothermal modification treatment, anodizing treatment, and chemical conversion treatment are preferably performed in advance with the above-described degreasing treatment.

  Of the above-mentioned treatments, in particular, the hot water denaturation treatment and the anodizing treatment dissolve the surface of the aluminum foil with a treating agent and further form an aluminum compound (boehmite, anodized) having excellent corrosion resistance. In order to form a co-continuous structure from the corrosion prevention layer to the corrosion prevention layer, there are cases where it is included in the definition of chemical conversion treatment, but only pure coating methods that are not included in the definition of chemical conversion treatment as described later It is also possible to form a corrosion prevention layer.

  This method uses a sol of a rare earth element-based oxide such as cerium oxide having an average particle size of 100 nm or less as a material that has an anticorrosion effect (inhibitor effect) of aluminum and is also suitable from an environmental viewpoint. Yes, by using this method, it is possible to impart an effect of preventing corrosion of a metal foil such as an aluminum foil even by a general coating method. The sol of rare earth element oxides such as cerium oxide can use various solvents such as aqueous, alcohol-based, hydrocarbon-based, ketone-based, ester-based, and ether-based solvents. It is preferable to use the sol. In order to stabilize the dispersion of such an oxide sol, an inorganic acid such as nitric acid, hydrochloric acid or phosphoric acid, or an organic acid such as acetic acid, malic acid, ascorbic acid or lactic acid is usually used as a dispersion stabilizer. . Among these dispersion stabilizers, phosphoric acid is not only “sol dispersion stabilization” but also a lithium battery packaging material for this application. "Improvement of adhesion", "Providing resistance to electrolyte" by capturing aluminum ions eluted under the influence of hydrofluoric acid, "Aggregation of oxide layer" "Strengthening" is expected. Examples of such phosphoric acid or salts thereof include orthophosphoric acid, pyrophosphoric acid, metaphosphoric acid, and alkali metal salts and ammonium salts thereof. In particular, condensed phosphoric acid such as trimetaphosphoric acid, tetrametaphosphoric acid, hexametaphosphoric acid, and ultrametaphosphoric acid, or alkali metal salts and ammonium salts thereof are also preferable for function expression as a lithium battery packaging material. In particular, an agent that is excellent in reactivity at low temperatures is preferable in consideration of dry film-forming properties (drying ability, heat amount) when a layer made of rare earth oxide is formed by various coating methods using the rare earth oxide sol. For this reason, Na ion salts having excellent dehydration condensation properties at low temperatures are preferably used. The salt forming the phosphate is not particularly limited, but more preferably a water-soluble salt. As for the compounding ratio of cerium oxide and phosphoric acid (or a salt thereof), 1 to 100 parts by weight of phosphoric acid (or a salt thereof) is mixed with 100 parts by weight of cerium oxide. If it is less than this value, the sol is not stabilized and it is difficult to satisfy the function as a packaging material for a lithium battery. More preferably, it is 5 parts by weight or more. It is mentioned that the upper limit of the phosphate content is not accompanied by a decrease in the function of the cerium oxide sol, and it is 100 parts by weight or less. Preferably it is 50 weight part or less, More preferably, it is 20 weight part or less.

  However, since the layer formed from the rare earth oxide sol described above is an aggregate of inorganic particles, the cohesive force of the layer itself is low even after the drying curing step. Therefore, in order to supplement the cohesive strength of this layer, it is preferable to combine with an anionic polymer or a cationic polymer described below. Specific examples of the anionic polymer include a polymer having a carboxyl group, and examples thereof include poly (meth) acrylic acid (or a salt thereof) or a copolymer having poly (meth) acrylic acid as a main component. Components used as a copolymer include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl as alkyl group Alkyl (meth) acrylate monomers that are groups, further (meth) acrylamide, N-alkyl (meth) acrylamide, N, N-dialkyl (meth) acrylamide (alkyl groups include methyl, ethyl, n- Propyl group, i-propyl group, n-butyl group, i-butyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group, etc.), N-alkoxy (meth) acrylamide, N, N-dialkoxy (meth) Acrylamide (alkoxy groups include methoxy, ethoxy, butoxy, isobutoxy, etc.), N Amide group-containing monomers such as methylol (meth) acrylamide and N-phenyl (meth) acrylamide, hydroxyl group-containing monomers such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate, glycidyl (meth) acrylate, allyl Copolymerizing glycidyl group-containing monomers such as glycidyl ether, silane-containing monomers such as (meth) acryloxypropyltrimethoxysilane, (meth) acryloxypropyltriethoxylane, and isocyanate group-containing monomers such as (meth) acryloxypropyl isocyanate Can be mentioned.

  These polymers are materials used to improve the stability of the oxide layer obtained using the rare earth element oxide sol as described above. The effect is to protect the hard and brittle oxide layer with an acrylic resin component, and also to trap phosphate-derived ion contamination (particularly sodium ions) contained in the rare earth oxide sol (cation catcher). ) Effect. The protective layer provided to prevent the corrosion of the aluminum foil by a corrosive compound is not limited to the lithium battery used in the present invention, and ion contamination, particularly alkali metal ions such as sodium and alkaline earth metal ions are included. Then, there is a problem that the protective layer is attacked starting from this ion contamination. That is, anionic polymers such as polyacrylic acid are effective in that ion contamination such as sodium ions contained in the rare earth element oxide sol described later is fixed and the resistance of the film is improved.

As described above, the polyanionic polymer can be used in combination with the rare earth element oxide sol as a corrosion prevention layer in the lithium battery packaging material, thereby providing the same corrosion prevention performance as that of the chromate treatment. More preferably, a structure in which a polyanionic polymer that is essentially water-soluble is cross-linked is preferable, and a compound having an isocyanate group, a glycidyl group, a carboxyl group, or an oxazoline group may be used as such a cross-linking agent. .

  Examples of the compound having an isocyanate group include tolylene diisocyanate, xylylene diisocyanate or hydrogenated product thereof, hexamethylene diisocyanate, 4-4 ′ diphenylmethane diisocyanate or hydrogenated product thereof, diisocyanates such as isophorone diisocyanate, or these isocyanates. Polyisocyanates such as adducts obtained by reacting polyhydric alcohols with polyhydric alcohols such as trimethylolpropane, burette obtained by reacting with water, or isocyanurates which are trimers, or polyisocyanates thereof. Examples thereof include blocked polyisocyanates obtained by blocking isocyanates with alcohols, lactams, oximes and the like.

  Examples of the compound having a glycidyl group include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, 1,4-butanediol, 1,6-hexanediol, Epoxy compounds made by reacting glycols such as neopentyl glycol and epichlorohydrin, epoxy compounds made by reacting polychlorinated alcohols such as glycerin, polyglycerin, trimethylolpropane, pentaerythritol, sorbitol and epichlorohydrin, terephthalic acid phthalate, sulphate Examples thereof include an epoxy compound obtained by reacting a dicarboxylic acid such as acid or adipic acid with epichlorohydrin.

  Examples of the compound having a carboxyl group include various aliphatic or aromatic dicarboxylic acids, and it is also possible to use poly (meth) acrylic acid or alkali (earth) metal salts of poly (meth) acrylic acid. is there. The compound having an oxazoline group is an acrylic monomer such as (meth) acrylic acid or (meth) acrylic when a low molecular compound having two or more oxazoline units or a polymerizable monomer such as isopropenyl oxazoline is used. Those obtained by copolymerization with an acid alkyl ester, hydroxyalkyl (meth) acrylate, or the like can be used. Further, like a silane coupling agent, an amine and a functional group can be selectively reacted to form a crosslinking point into a siloxane bond. In this case, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-chloropropylmethoxysilane, vinyltrichlorosilane, γ -Mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β (aminoethyl) -γ-aminopropyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane, particularly cationic polymers or co-polymers thereof. In view of the reactivity with the polymer, epoxy silane, amino silane, and isocyanate silane are preferably used. These crosslinking agents are suitably used in an amount of 1 to 50 parts per 100 parts of the anionic polymer. If it is less than 1 part, the crosslinked structure is insufficient, and if it is more than 50 parts, the coating pot life may be reduced. Preferably, it is 10 to 20 parts. The method for crosslinking the water-soluble polymer is not limited to the above-mentioned crosslinking agent, and a crosslinked structure such as ionic crosslinking using titanium or a zirconium compound may be formed.

On the other hand, examples of the cationic polymer include an amine-containing polymer, polyethyleneimine, an ionic polymer complex composed of a polymer having polyethyleneimine and a carboxylic acid, and a primary amine-grafted acrylic obtained by grafting a primary amine to an acrylic main skeleton. Examples thereof include resins, polyallylamine or derivatives thereof, and aminophenol. In addition, as a polymer having a carboxylic acid that forms an ionic polymer complex with polyethyleneimine, polyacrylic acid (salt) such as polyacrylic acid or an ionic salt thereof, a copolymer in which a comonomer is introduced, carboxymethylcellulose, The polysaccharide which has carboxyl groups, such as the ionic salt, is mentioned. As the polyallylamine, homopolymers or copolymers of allylamine, allylamine amide sulfate, diallylamine, dimethylallylamine and the like can be used. Furthermore, these amines can be free amines or stabilized with acetic acid or hydrochloric acid. It is possible to use. Further, maleic acid, sulfur dioxide or the like can be used as a copolymer component. Furthermore, it is possible to use a type in which a primary amine is partially methoxylated to impart thermal crosslinkability. Aminophenol can also be used. Particularly preferred is allylamine or a derivative thereof. The reason for this is that as a result of sincerity studies using various compounds to provide the electrolyte resistance and hydrofluoric acid resistance required for lithium battery packaging materials, the cationic polymer itself also has electrolyte resistance and hydrofluoric acid resistance. This is because they have been found to be a compound capable of imparting. This is presumed to be because the fluorine ions are trapped by a cationic group (anion catcher), thereby suppressing damage to the aluminum foil.

  The above-mentioned cationic polymer is a very preferable material from the viewpoint of improving adhesiveness. More preferably, this cationic polymer is also water-soluble like the above-mentioned anionic polymer, so that it is preferable to form a crosslinked structure. By using the crosslinking agent having various functional groups already described, It becomes possible to impart water resistance of the polymer. In other words, it means that the cationic polymer also forms a crosslinked structure. Therefore, when the rare earth oxide sol is used as the above-mentioned corrosion prevention treatment layer, instead of using the anionic polymer as the protective layer, the cationic polymer is used. A polymer may be used.

As an example of the combination of the above-mentioned coating type corrosion prevention treatment from the above contents,
(1) Rare earth oxide sol only (2) Anionic polymer only (3) Cationic polymer only (4) Rare earth oxide + anionic polymer (laminated composite)
(5) Rare earth oxide + cationic polymer (laminated composite)
(6) (rare earth oxide + anionic polymer: laminated composite) / cationic polymer (multilayered)
(7) (Rare earth oxide + cationic polymer: laminated composite) / anionic polymer (multilayered)
However, it is not limited to these. For example, as an example of selecting a corrosion prevention treatment layer, a cationic polymer is a very preferable material in terms of improving the adhesiveness with the above-described adhesive resin, and therefore has a particularly high demand for electrolyte resistance (long term). For applications where reliability is required, it is preferable to use a cationic polymer as a component of the corrosion prevention treatment layer.

Not limited to the contents described above, for example, by using an agent in which phosphoric acid and a chromium compound are blended in a resin binder (acrylic resin, aminophenol resin, etc.), such as a coating type chromate that is a known technique, the corrosion prevention function and adhesion It is possible to form a layer having both properties. In addition, for the above-described degreasing treatment, hydrothermal modification treatment, anodizing treatment, chemical conversion treatment, or a combination of these treatments, the above-described cationic polymer or anionic polymer is used to improve the adhesion. A cationic polymer or an anionic polymer can be laminated as a multilayer structure for a combination of these treatments. In addition, although it is necessary to consider the stability of the coating liquid, it is also possible to use a coating agent obtained by previously making one solution of the rare earth oxide sol and the cationic polymer or anionic polymer described above. . The corrosion prevention treatment layer described so far is preferably provided in the range of 0.005 to 0.200 g / m ² . More preferably, it is the range of 0.010-0.100 g / m < ² >. When it is thinner than 0.005 g / m ^2, it affects the corrosion prevention function of the aluminum foil layer. If it is thicker than 0.200 g / m ² , the performance of the corrosion prevention function is saturated, or in the case of using a rare earth oxide sol, if the coating is thick, curing due to heat during drying becomes insufficient. , There is a risk of a decrease in cohesive strength. In the above description, the weight per unit area is described, but if the specific gravity is known, the thickness can be converted therefrom. Although the above-described corrosion prevention layer is mainly provided on the inner layer side, although not described in this specification, a similar treatment may be provided on the opposite surface side (adhesive side).

  Unlike the chemical conversion treatment typified by the chromate treatment, the coating-type corrosion prevention treatment layer described above does not require an inclined structure to be formed between the aluminum foil layer and the chemical conversion treatment layer. In order to form a gradient structure with this aluminum foil, the chemical conversion treatment represented by chromate is performed on the aluminum foil using a chemical conversion treatment agent containing hydrofluoric acid, hydrochloric acid, nitric acid, sulfuric acid or a salt thereof. As described above, the chemical conversion treatment layer is formed on the aluminum foil by reacting with a chromium-free compound. However, since these treatment agents use an acid, they are accompanied by corrosion of the work environment and coating equipment. The coating layer used in the present invention described above does not need to form an inclined structure with respect to the aluminum foil, and in that respect, the definition is different from the chemical conversion treatment. As a result, since the properties of the coating agent are not restricted by acidity, alkalinity or neutrality, it can be said that it is a treatment method that is also friendly to the work environment. Considering this, it can be said that the content is also interesting from the point of view of the corrosion prevention technical field where an alternative is desired.

<Adhesive resin layer>
The adhesive resin layer 25 is a layer that bonds the sealant layer 30 and the aluminum foil layer 15 on which the corrosion prevention treatment layer 20 is formed. The resin constituting the adhesive resin layer 25 is preferably an acid-modified polyolefin resin or an acid-modified elastomer resin obtained by graft-modifying maleic anhydride or the like to a polyolefin resin or an elastomer resin. Examples of the polyolefin resin include low density, medium density, and high density polyethylene, ethylene-α olefin copolymer, homo, block, random polypropylene, and propylene-α olefin copolymer. These polyolefin resins may be used individually by 1 type, and may use 2 or more types together. As a result, it is possible to provide a battery container that has excellent resistance to contents such as an electrolytic solution and does not have a decrease in adhesion due to deterioration of the adhesive resin even when hydrofluoric acid is generated. At this time, the thickness of the adhesive resin layer 25 is preferably 1 to 40 μm, and more preferably 5 to 20 μm. This is because if the adhesive resin layer is thinner than 1 μm, the adhesive strength cannot be maintained, and if it is thicker than 40 μm, moisture permeation becomes high.

  The adhesive resin layer may be bonded using the following adhesive in addition to the above-described polyolefin resin, acid-modified polyolefin resin, or acid-modified elastomer resin. That is, as the adhesive used at this time, there is a risk of swelling by the electrolytic solution or hydrolysis by hydrofluoric acid. Therefore, as the adhesive for use in this application, a skeleton main component that is difficult to hydrolyze is used, and the crosslinking density is improved. It is necessary to design the composition.

  For example, as a technique for improving the crosslinking density, dimer fatty acid or its ester or its hydrogenated product, or dimer fatty acid or its ester or its hydrogenated reducing glycol can be used. Dimer fatty acid is a dimerization of various unsaturated fatty acids, and its structure can be acyclic, monocyclic, polycyclic, and aromatic, but the polyester used in this adhesive The polybasic acid that is a raw material of the polyol is not particularly limited. Also, fatty acids that are starting materials for dimer fatty acids are not restricted. Examples of the unsaturated fatty acid include crotonic acid, myristoleic acid, palmitoleic acid, oleic acid, elaidic acid, vaccenic acid, gadoleic acid, eicosenoic acid, erucic acid, and nervonic acid. Examples of diunsaturated fatty acids include linoleic acid, eicosadienoic acid, and docosadienoic acid. Examples of the triunsaturated fatty acid include linolenic acid, vinolenic acid, eleostearic acid, mead acid, dihomo-γ-linolenic acid, and eicosatrienoic acid. Examples of tetraunsaturated fatty acids include stearidonic acid, arachidonic acid, eicosatetraenoic acid, and adrenic acid. Examples of the pentaunsaturated fatty acid include boseopentaenoic acid, eicosaventaenoic acid, ozbond acid, sardine acid, and tetracosaventaenoic acid. Examples of the hexaunsaturated fatty acid include docosahexaenoic acid and nisic acid. The combination of fatty acids when dimerizing fatty acids may be any combination. This bulky hydrophobic unit of dimer fatty acid improves the crosslink density as an adhesive.

  A dibasic acid such as that used in ordinary polyester polyols may be introduced using the dimer fatty acid as an essential component. For example, it is possible to select from aliphatic systems such as succinic acid, glutaric acid, adipic acid, pimelic acid, speric acid, azelaic acid, sebacic acid and brassic acid, and aromatic systems such as isophthalic acid, terephthalic acid and naphthalenedicarboxylic acid. Is possible. And ethylene glycol, propylene glycol, butanediol, neopentyl glycol, methylpentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, dodecanediol, etc. aliphatic, cyclohexanediol, hydrogenated xylylene glycol, etc. A component obtained by using one or more aromatic diols such as alicyclic and xylylene glycol can be used as the main component (polyester polyol) of the adhesive used in the present invention. Further, the hydroxyl groups at both ends of the polyester polyol are, for example, 2,4- or 2,6-tolylene diisocyanate, xylylene diisocyanate, 4,4′-diphenylmethane diisocyanate, methylene diisocyanate, isopropylene diisocyanate, lysine diisocyanate, 2, 2,4- or 2,4,4-trimethylhexamethylene diisocyanate, 1,6-hexamethylene diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isopropylidene dicyclohexyl-4,4'-diisocyanate From the above-mentioned isocyanate compound selected from a simple substance of at least one isocyanate compound selected from Adducts, biuret body, such as a polyester urethane polyol chain extension with isocyanurate products thereof. In addition, the isocyanate component described later can also be used as a chain extender for polyester polyol.

  As the curing agent for the main agent, it is possible to use the same type of isocyanate compound used as the chain extender of the polyester polyol, and although it is repeated, 2,4- or 2,6-tolylene diisocyanate, xylylene Range isocyanate, 4,4'-diphenylmethane diisocyanate, methylene diisocyanate, isopropylene diisocyanate, lysine diisocyanate, 2,2,4- or 2,4,4-trimethylhexamethylene diisocyanate, 1,6-hexamethylene diisocyanate, methylcyclohexane diisocyanate , Isophorone diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, isopropylidene dicyclohexyl-4,4′-diisocyanate, etc. Single sulfonate compounds, or adducts formed of the above isocyanate compounds selected from at least one or more, biuret body, isocyanurate products thereof. Furthermore, for the purpose of improving the resistance to electrolytic solution (especially solubility / swellability in electrolytic solution), polyisocyanate alone or a mixture selected from crude tolylene diisocyanate, crude (or polymeric) diphenylmethane diisocyanate, or adducts thereof. It is effective to use. The use of these curing agents leads to improvement in solubility and swelling property due to improvement in the crosslinking density of the adhesive coating film, and the urethane group concentration increases, so that improvement in substrate adhesion is also expected. The use of the above-mentioned crude tolylene diisocyanate or crude (or polymeric) diphenylmethane diisocyanate as a chain extender of the above-described polyester polyol can also be said to be a suitable material for use as an exterior material for a lithium battery. As a ratio of the main agent and the curing agent which is an adhesive composition, 1 part to 100 parts of a curing agent may be mentioned with respect to 100 parts of the main agent. When the amount is less than 1 part, performance is not exhibited in terms of adhesion and electrolyte resistance. If the amount is more than 100 parts, an excess of isocyanate groups will be present, which may affect the adhesive film quality due to the unreacted residue and the hardness. More preferably, it is in the range of 5 to 50 parts. Moreover, it is also possible to mix | blend the carbodiimide compound, oxazoline compound, epoxy compound, phosphorus compound, silane coupling agent, etc. for adhesion promotion mentioned above.

<Sealant layer>
The resin constituting the sealant layer 30 is preferably a thermoplastic resin, and examples of the component include polyolefin resins such as polyethylene and polypropylene. Thereby, a battery excellent in impact resistance and heat sealability can be provided. Examples of the polypropylene include homopolypropylene, random polypropylene, and block polypropylene. These may be a single layer film or a film in which a plurality of layers are laminated. This makes it possible to select the fusing temperature and altitude, and to select impact resistance and heat seal according to the purpose. At this time, the thickness of the sealant layer 30 is preferably 25 to 100 μm. This is because if the sealant layer is thinner than 25 μm, the sealing strength cannot be maintained, and if it is thicker than 100 μm, the moisture permeation becomes high. The sealant layer 30 may be blended or coated with various additives such as a flame retardant, slip agent, anti-blocking agent, antioxidant, light stabilizer, and tackifier.

<Method for producing a container for a lithium ion battery>
Next, although the manufacturing method of the packaging material for lithium ion batteries of this invention shown in FIG. 1 is described, it is not limited to this.

<Lamination process of corrosion prevention treatment layer to aluminum foil layer>
A corrosion prevention treatment layer is formed on the aluminum foil described above. Examples of the method include degreasing treatment, hydrothermal alteration treatment, anodizing treatment, chemical conversion treatment, or coating with a coating agent having corrosion prevention performance. For degreasing treatment, annealing method, spray method or dipping method, for hydrothermal conversion treatment or anodizing treatment, dipping method, for chemical conversion treatment, select dipping method, spray method, coating method etc. according to the type of chemical conversion treatment Is possible. Various coating methods such as gravure coating, reverse coating, roll coating, and bar coating can be used as the coating method of the coating agent having corrosion prevention performance. As described above, the treatment may be performed on both sides or on one side, but in the case of single-side treatment, the treatment surface is applied to the side laminated with the adhesive resin layer (AR). The coating amount to be provided is as described above. Moreover, when drying cure is required, it can carry out in the range of 60 to 300 degreeC as base material temperature according to the drying conditions of the corrosion prevention process layer to be used.

<Bonding process of base material layer and aluminum foil layer>
The aluminum foil layer 15 on which the corrosion prevention treatment layer 20 is formed and the base material layer 5 are bonded together. As a method of bonding, dry lamination, non-solvent lamination, wet lamination, and the like are used, and both are bonded with a polyurethane adhesive mainly composed of polyester polyol, polyether polyol, and acrylic polyol, and the base material layer 5 A laminate composed of / adhesive layer 10 / aluminum foil layer 15 / corrosion prevention treatment layer 20 is produced.

<Lamination process of sealant layer>
A sealant layer 30 is laminated on the laminate. Examples of the lamination method include wet lamination, extrusion lamination, dry lamination, hot melt lamination, non-solvent lamination, heat lamination, and the like. In the case of extrusion lamination, the adhesive resin layer 25 is extrusion laminated on the corrosion prevention treatment layer of the laminate, and the sealant layer 30 is laminated to produce a packaging material for a lithium ion battery. The corrosion prevention treatment layer 20 may be provided in-line during this extrusion lamination. Thereafter, for the purpose of improving the adhesion between the corrosion prevention treatment layer 20 and the adhesive resin layer 25, heat treatment (aging treatment, thermal lamination, etc.) is performed. It is also possible to create a multilayer film with the adhesive resin 25 and the sealant layer 30 and to laminate the laminate on the laminate by thermal lamination.

  Although the Example of this invention is shown below, it is not necessarily limited to this.

[Materials used]
The materials used in the following examples are as follows.
<Base material layer (SB)>
● SB-1: 25 μm-2 biaxially stretched polyamide film (ON manufactured by Unitika Ltd.)

<Adhesive (AD-1)>
● AD-1: Polyurethane adhesive (made by Toyo Ink Co., Ltd.) blended with adduct curing agent of tolylene diisocyanate to polyester polyol main agent

<Aluminum foil layer (AL)>
● AL-1: Annealed and degreased 40 μm-soft aluminum foil 8079 (Toyo Aluminum Co., Ltd.)

<Corrosion prevention treatment layer (CL)>
CL-1: “Sodium polyphosphate stabilized cerium oxide sol” adjusted to a solid content concentration of 10 wt% using distilled water as a solvent was used. The phosphate is 10 parts by weight per 100 parts by weight of cerium oxide.
CL-2: 90 wt% “polyacrylic acid ammonium salt (manufactured by Toagosei Co., Ltd.)” adjusted to a solid content concentration of 5 wt% using distilled water as a solvent and “acrylic-isopropenyloxazoline copolymer (manufactured by Nippon Shokubai Co., Ltd.) ) "A composition consisting of 10 wt% was used.
CL-3: Using a 1% concentration phosphoric acid aqueous solution as a solvent and using a water-soluble phenol resin (manufactured by Sumitomo Bakelite Co., Ltd.) adjusted to a solid content concentration of 1 wt%, chromium fluoride (CrF ₃ ) The chemical conversion treatment agent whose concentration was adjusted so that the amount of Cr present was 10 mg / m ² was used.

<Adhesive (AD-2)>
● Main agent-1: Polyester polyol consisting of hydrogenated dimer fatty acid and diol ● Curing agent-1: Crude tolylene diisocyanate, crude (or polymeric) diphenylmethane diisocyanate mixture, or adducts thereof (Mitsui Chemicals, Inc.)

<Adhesive resin layer (AD-3)>
Adhesive resin-1: Elastomer made of an ethylene-α olefin copolymer for modified PP obtained by graft-modifying maleic anhydride on a random polypropylene (PP) base (Tm (AR) = about 135 ° C.) Modified polyolefin resin (Mitsui Chemicals) was used.

<Sealant layer (SL)>
SL-1: A two-type three-layer multilayer film composed of random PP / block PP / random PP having a total thickness of 60 μm was used (manufactured by Okamoto)

[Production method]
On the side of the aluminum foil layer (AL) that is filled with the electrolytic solution, a corrosion prevention treatment layer (CL) was provided by micro gravure coating. The coating amount was set to 70 to 100 mg / m ² as a dry coating amount of the coating agent, and baking treatment was performed at 150 to 250 ° C. according to the type of the coating agent in the drying unit. In the examples described below, the case where the corrosion prevention treatment layer (CL) is multilayered with the above-described components is also described, but the final dry coating amount is 70 for both single and multilayer layers. and -100 mg / ^{m 2,} the baking temperature conditions were also carried out in the range of 150 to 250 ° C..

The base material layer (SB) was laminated | stacked on the outer layer side of the aluminum foil (AL) which provided the corrosion prevention process layer (CL) using the adhesive agent (AD-1). At this time, lamination was performed by gravure reverse coating so that the dry coating amount was 4 to 5 g / m ² . Then, the adhesive agent (AD-1) was hardened by performing an aging process.

Thereafter, a sealant layer (SL) was laminated using an adhesive (AD-2) on the corrosion prevention treatment layer (CL) side of the laminate. At this time, lamination was similarly performed by gravure reverse coating so that the dry coating amount was 4 to 5 g / m ² . Thereafter, by performing an aging treatment, a dry lamination structure as shown in FIG. 1 in which the adhesive (AD-2) is cured can be obtained. On the other hand, trial evaluation is also conducted on the thermal laminate / heat treatment configuration. This production method uses an extrusion laminating machine to perform extrusion lamination on the corrosion prevention treatment layer (CL) so that the modified polyolefin resin is in the range of 260 ° C. to 300 ° C. as an adhesive resin (AD-3), By performing sandwich lamination with the sealant layer (SL), a sample having a laminated structure as shown in FIG. 1 was prepared. Thereafter, thermocompression bonding is performed by a thermal lamination method so that the base material temperature is close to the melting point of the sealant layer, and the corrosion prevention treatment layer (CL) and the adhesive resin layer (AD-3) are firmly adhered to each other. A heat treatment configuration was obtained. The laminate-type outer packaging material for lithium batteries finally obtained was used for the evaluation described below.

[Production of containers for lithium-ion batteries]
FIG. 3 shows an example of the sealing method of the outer packaging material for a lithium ion battery of the present invention, in which the seal bar of the heat sealing device and the heat sealing portion of the outer packaging material of the lithium ion battery are enlarged. As a heat sealing method, an edge portion of the outer packaging material for a lithium ion battery is sandwiched between upper and lower seal bars so that the sealant layers face each other, and heat-pressed at a predetermined temperature, a predetermined time, and a predetermined pressure. . At this time, a knurled portion is provided on the upper seal bar, and the adhesive resin layer and the sealant layer of the thin seal portion formed thinner by the knurled portion than the total thickness H1 of the adhesive resin layer and the sealant layer of the thick seal portion. The edge part of the exterior material was heat-sealed so that the total thickness H2 decreased.

[Evaluation]
<Seal strength evaluation>
Using the heat sealing method, the sealant layers are stacked so that the sealant layers face each other and heat sealed, and then cut into a strip of 100 × 15 mm size, from the inner seal end to the outer seal end or seal end. The seal strength was measured over the edge at a tensile speed of 300 m / min. In addition, the result whose seal strength is 40 N / 15 mm or more was regarded as acceptable.

<Evaluation of moisture permeability>
Using the heat sealing method, 120 mm x 110 mm lithium ion battery exterior materials are stacked so that the sealant layers face each other, folded to an external dimension of 120 mm x 55 mm, and heat sealed with 10 mm width on both edges. By doing so, the bag which one side opened was produced. Thereafter, 5 ml of an electrolytic solution in which ethylene carbonate, dimethyl carbonate, and diethyl carbonate as the battery contents were mixed at a ratio of 1: 1: 1 was injected, and the remaining one side was heat-sealed with a width of 5 mm. Note that the 10 mm seal part was regarded as having almost no moisture permeation, and the 5 mm seal part was used as the measurement target. The produced battery container was stored for 4 weeks in an environment of 60 ° C. and 95% RH, the amount of water contained in the electrolyte after storage was measured with a Karl Fischer, and the result with a water permeability of 100 ppm or less was passed. did.

  Hereinafter, each battery container was produced according to the laminates and processing conditions shown in Examples 1 to 9 and Comparative Examples 1 to 5. Moreover, seal strength (burst part, center part) and moisture permeability were evaluated using each produced battery container. In addition, each seal width was 5 mm in total of the normal seal part and the knurled seal part. The results are shown in Table 1.

<Example 1>
CL-1 was applied to the aluminum foil (AL) as a corrosion prevention treatment layer (CL), and further CL-2 was applied thereon. Moreover, the laminated body was produced using AD-3 as an adhesive resin layer (AR). A battery container was prepared using the laminate. The entire seal width was heat-sealed in a knurled shape.
[Knurled thin seal]
・ The thickness of the thin seal part is 40% of the thickness of the thick seal part.
・ Total thickness of adhesive resin layer and sealant layer 60μm
-The unit width of the thin seal part in the cross section is 30% of the unit width of the thick seal part
[Knurled thick seal]
・ Total thickness of adhesive resin layer and sealant layer 150μm

<Example 2>
A battery container was produced in the same manner as in Example 1, except that the thickness of the thin seal portion of the knurled seal portion and the total thickness of the adhesive resin layer and the sealant layer of the thin seal portion were changed.
[Knurled thin seal]
・ The thickness of the thin seal part is 60% of the thickness of the thick seal part.
・ Total thickness of adhesive resin layer and sealant layer 90μm

<Example 3>
A battery container was produced in the same manner as in Example 1, except that the thickness of the thin seal portion of the knurled seal portion and the total thickness of the adhesive resin layer and the sealant layer of the thin seal portion were changed.
[Knurled thin seal]
・ The thickness of the thin seal part is 20% of the thickness of the thick seal part.
・ Total thickness of adhesive resin layer and sealant layer 30μm

<Example 4>
A battery container was produced in the same manner as in Example 1 except that the unit width of the thin seal portion in the cross section of the knurled seal portion was changed to 20% of the unit width of the thick seal portion.

<Example 5>
A battery container was produced in the same manner as in Example 1 except that the unit width of the thin seal portion in the cross section of the knurled seal portion was changed to 60% of the unit width of the thick seal portion.

<Example 6>
In the heat seal area of the battery container, 1 mm (20% of the total heat seal width) is applied to the innermost and outermost areas, and a knurled (network structure) heat seal is applied to the other heat seal areas. A battery container was prepared in the same manner as in Example 1 except that the knurled (network structure) heat seal width was 60% symmetrical to the total heat seal width.

<Example 7>
In the heat seal area of the battery container, normal heat seal is applied to the innermost and outermost areas by 2 mm (40% of the total heat seal width), and knurled (network structure) heat seal is applied to the other heat seal areas. A battery container was prepared in the same manner as in Example 1 except that the knurled (network structure) heat seal width was 20% symmetrical to the total heat seal width.

<Example 8>
A battery container was prepared in the same manner as in Example 1 except that CL-3 was applied to the aluminum foil (AL) as the corrosion prevention treatment layer (CL).

<Example 9>
A battery container was prepared in the same manner as in Example 1 except that AD-2 was used as the adhesive resin layer (AR).

<Comparative Example 1>
Using a laminate having a total thickness of 30 μm of the adhesive resin layer and the sealant layer, a normal heat seal was applied to the entire heat seal region, and a battery container was produced in the same manner as in Example 1.

<Comparative Example 2>
Using a laminate having a total thickness of 120 μm of the adhesive resin layer and the sealant layer, a normal heat seal was applied to the entire heat seal region, and a battery container was produced in the same manner as in Example 1.

<Comparative Example 3>
A battery container was produced in the same manner as in Example 1, except that the thickness of the thin seal portion of the knurled seal portion and the total thickness of the adhesive resin layer and the sealant layer of the thin seal portion were changed.
[Knurled thin seal]
・ The thickness of the thin seal part is 80% of the thickness of the thick seal part.
・ Total thickness of adhesive resin layer and sealant layer 120μm
[Knurled thick seal]
・ Total thickness of adhesive resin layer and sealant layer 150μm

<Comparison result>
As a result of measuring the sealing strength and moisture permeability of the battery containers obtained in Examples 1 to 9 and Comparative Examples 1 to 3, the inventive products according to Examples 1 to 9 all have a sealing strength of 40 N / 15 mm or more. In addition, the moisture permeability was 100 ppm or less, and good results were shown. On the other hand, the comparative example products of Comparative Examples 1 to 3 have a low seal strength of 20 N / 15 mm in the central part in Comparative Example 1, and the water permeability exceeds 100 ppm in Comparative Examples 2 to 3, both pass. It did not reach (practical level). As described above, according to the present invention, by setting the total thickness of the adhesive resin layer and the sealant layer partially thin by sealing the heat seal portion in a knurled shape, it is possible to suppress moisture permeation and ensure sealing strength. The battery container which is possible and is hard to break, and the result which can provide the lithium ion battery provided with this were obtained.

DESCRIPTION OF SYMBOLS 1 Laminated body 2 Seal bar 3 Base material 10 Adhesive layer 15 Aluminum foil layer 20 Corrosion prevention processing layer 25 Adhesive resin layer 30 Sealant layer 40 Thin seal part 50 Thick seal part 60 Thin seal part Unit width of 70 Unit width of thick seal part 80 Seal width of whole seal H1 Total thickness of adhesive resin layer and sealant layer of thin seal part H2 Total thickness of adhesive resin layer and sealant layer of thick seal part

Claims (2)

A battery container formed by laminating at least one aluminum foil layer, an adhesive resin layer, and a sealant layer in sequence on one side of the base material so that the sealant layer side is opposed to each other and the periphery of the edge is heat-sealed. The shape of the heat seal includes a knurled structure (network structure) having a thin seal portion and a thick seal portion, and the adhesive resin layer and the sealant layer occupy the thin seal portion. The total thickness is 70% or less of the total thickness of the adhesive resin layer and the sealant layer in the thick seal portion, and the unit width of the thin seal portion is 20% of the unit width of the thick seal portion. 60% or less, and the region heat-sealed to the knurled structure is 20% or more and 80% or less of the entire heat seal width . A lithium ion battery comprising the battery container according to claim 1 .