JP2013097985A - Air secondary battery packaging material, air secondary battery packaging material manufacturing method, and air secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air secondary battery packaging material which excels in bondability between a package sheet and an oxygen permeable layer and also exhibits excellent oxygen permeability.SOLUTION: The air secondary battery packaging material comprises: a package sheet which consists of a laminate structure composed of an outer layer a metal foil layer and an inner layer including a thermoplastic rein film, and which has an oxygen intake opening provided therein, penetrating the outer layer, the metal foil layer and the inner layer; and an oxygen permeable film which is joined to the inner layer side on the periphery of the opening so as to cover the opening. On the bonded face of one of or both of the outer edge of the oxygen permeable layer and the periphery of the opening, a silane coupling agent containing a reactive functional group is applied.

Description

  The present invention relates to an exterior material for an air secondary battery, a method for producing an exterior material for an air secondary battery, and an air secondary battery.

  As electronic devices such as video cameras, notebook computers, and mobile phones become more portable and smaller, there is an increasing demand for smaller and lighter batteries as driving sources, and high-performance lithium secondary batteries are widely used. Has reached. Recently, in order to apply a lithium secondary battery to an in-vehicle power source of an electric vehicle or a hybrid vehicle, an increase in the size of the lithium secondary battery has been studied.

  By the way, since the mounting space of the in-vehicle power source in the vehicle is limited and the shape of the mounting space is not constant, the lithium secondary battery for in-vehicle use is downsized (thinned) as in the case of electronic devices. There is also a need for weight reduction and freedom of shape. As an exterior material of such a lithium secondary battery, for example, an exterior sheet as disclosed in Patent Document 1 below is known. The exterior sheet of Patent Document 1 is formed by laminating an outer layer made of a resin layer, an inner layer made of an aluminum foil and a resin layer, and heat sealability is imparted to the inner resin layer. Lithium secondary battery with excellent hermeticity and freedom of shape by processing such an outer sheet into a bag shape to form a packaging container, inserting cells into the packaging container, and heat sealing the inner layers of the outer sheet. Is obtained.

  Recently, attention has been paid to an air secondary battery using lithium or aluminum as a negative electrode active material and oxygen in the air as a positive electrode active material. Since oxygen in the air is used as the positive electrode active material, an improvement in energy density per battery volume is expected. For example, a lithium-air secondary battery, which is a type of air secondary battery, has an exterior material in which metallic lithium as a negative electrode active material and an electrolyte are enclosed, and the exterior material is provided with a window for taking in oxygen. An air electrode is bonded to the part (see Patent Document 2). The air electrode is configured to include an oxygen permeable membrane and a catalyst layer. The oxygen permeable membrane is joined to the window portion of the exterior material, so that the air electrode is disposed in the window portion. As an oxygen permeable membrane, for example, an anion exchange membrane is known. In addition, as an exterior material, adoption of a conventional exterior sheet for a lithium secondary battery has been studied.

Japanese Patent No. 4431822 JP 2011-96492 A

  However, in the conventional air secondary battery, the bonding between the outer sheet and the oxygen permeable membrane made of an anion exchange membrane is insufficient, and the shortage of the air secondary battery due to leakage of electrolyte or intrusion of carbon dioxide from the outside. Life expectancy was a problem. In addition, there is a problem that the oxygen permeable membrane swells when it comes into contact with the electrolyte inside the air secondary battery, and there is a possibility that the oxygen permeation may be disturbed.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an exterior material for an air secondary battery that is excellent in bondability between an exterior sheet and an oxygen permeable membrane and that provides good oxygen permeability. To do. It is another object of the present invention to provide a method for manufacturing an exterior material for an air secondary battery that can improve the bondability between the exterior sheet and the oxygen permeable membrane and can realize good oxygen permeability. Furthermore, an object of the present invention is to provide an air secondary battery that can prevent leakage of electrolyte and intrusion of carbon dioxide from the outside.

The present invention relates to the following.
[1] An oxygen capturing opening that is formed by laminating an outer layer including a heat-resistant resin film, a metal foil layer, and an inner layer including a thermoplastic resin film, and penetrates the outer layer, the metal foil layer, and the inner layer. An exterior sheet provided with,
An oxygen permeable membrane bonded to the inner layer side of the periphery of the opening so as to cover the opening,
An exterior for an air secondary battery, wherein a silane coupling agent having a reactive functional group is applied to one or both of the outer peripheral portion of the oxygen permeable membrane and the peripheral portion of the opening or both. Wood.
[2] The reactive functional group of the silane coupling agent is selected from the group consisting of vinyl group, epoxy group, styryl group, methacryl group, acrylic group, amino group, ureido group, mercapto group, sulfide group, and isocyanate group. The packaging material for an air secondary battery according to [1], which has any one of the above at the end.
[3] The air secondary battery outer packaging material according to [1] or [2], wherein the inner layer is made of an acid-modified polyolefin resin film.
[4] The oxygen permeable membrane is an anion exchange membrane, and is any one selected from the group consisting of a sulfo ion exchange resin, a fluorine ion exchange resin, and a strongly basic negative ion exchange resin. 3] The packaging material for an air secondary battery according to any one of [3].
[5] The exterior material for an air secondary battery according to any one of [1] to [4], wherein the exterior sheet and the oxygen permeable membrane are pressure-bonded or bonded.
[6] The air secondary battery exterior material according to any one of [1] to [5], wherein a silane coupling agent having a hydrophobic functional group is further applied to the oxygen permeable membrane.
[7] An air secondary battery comprising the outer packaging material for an air secondary battery according to any one of [1] to [6].
[8] The outer layer including the heat-resistant resin film, the metal foil layer, and the inner layer including the thermoplastic resin film are laminated, and an opening for oxygen uptake that penetrates the outer layer, the metal foil layer, and the inner layer A step of applying a reactive functional group-containing silane coupling agent to the peripheral portion of the opening portion of the exterior sheet provided with the outer peripheral portion of the oxygen-permeable membrane or the bonding surface of either or both of the oxygen-permeable membrane; and
Bonding the oxygen permeable membrane to the periphery of the opening of the exterior sheet;
The manufacturing method of the exterior material for air secondary batteries characterized by comprising.
[9] The reactive functional group of the silane coupling agent is selected from the group consisting of vinyl group, epoxy group, styryl group, methacryl group, acrylic group, amino group, ureido group, mercapto group, sulfide group, and isocyanate group. The manufacturing method of the exterior material for air secondary batteries as described in [8] which has any 1 type by the terminal.
[10] The method for producing an exterior material for an air secondary battery according to [8] or [9], wherein the inner layer is made of an acid-modified polyolefin resin film.
[11] The oxygen permeable membrane is an anion exchange membrane, and is any one selected from the group consisting of a sulfo ion exchange resin, a fluorine ion exchange resin, and a strongly basic negative ion exchange resin. 10] The manufacturing method of the exterior material for air secondary batteries as described in any one of [10].
[12] The method for manufacturing an exterior material for an air secondary battery according to any one of [8] to [11], wherein the exterior sheet and the oxygen permeable membrane are pressure-bonded or bonded.
[13] Any one of [8] to [12], wherein a silane coupling agent having a hydrophobic functional group is applied to the oxygen permeable membrane, and then a silane coupling agent having a reactive functional group is applied. The manufacturing method of the exterior material for air secondary batteries as described in 1 item | term.

  According to the outer packaging material for an air secondary battery of the present invention, when the inner layer including the thermoplastic resin film and the oxygen permeable membrane are bonded, at least one of the inner layer and the oxygen permeable membrane has a reactive functional group. Since the agent is applied, the bonding strength between the inner layer and the oxygen permeable membrane is improved, the resistance to the electrolytic solution is increased, the swelling of the oxygen permeable membrane can be suppressed, and good oxygen permeability can be obtained.

  In addition, according to the air secondary battery of the present invention, since the air secondary battery exterior material having improved bonding strength between the inner layer and the oxygen permeable membrane is provided, electrolyte leakage or carbon dioxide intrusion from the outside It is possible to prevent the air secondary battery from being shortened.

  Furthermore, according to the method for manufacturing an outer packaging material for an air secondary battery of the present invention, when the inner layer containing the thermoplastic resin film and the oxygen permeable membrane are bonded, at least one of the inner layer and the oxygen permeable membrane has a reactive functional group. As a result, the bonding strength between the inner layer and the oxygen permeable membrane is improved, the resistance to the electrolytic solution is enhanced, and the oxygen permeable membrane is prevented from swelling and has good oxygen permeability. realizable.

FIG. 1 is a perspective view showing an air secondary battery exterior material according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing an air secondary battery exterior material according to an embodiment of the present invention. FIG. 3 is a partial cross-sectional view showing an exterior sheet constituting an exterior material for an air secondary battery according to an embodiment of the present invention. FIG. 4 is a partial cross-sectional view showing an example of an air secondary battery according to an embodiment of the present invention. FIG. 5 is a partial cross-sectional view showing another example of the air secondary battery according to the embodiment of the present invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of an air secondary battery exterior material, an air secondary battery exterior material manufacturing method, and an air secondary battery according to the present invention will be described with reference to the drawings.

[Exterior material for air secondary battery]
As shown in FIGS. 1 and 2, an exterior sheet 1 for an air secondary battery (hereinafter referred to as an exterior material), which is a preferable aspect of the present embodiment, is an exterior sheet 2 provided with an opening 12 for oxygen uptake. And the oxygen permeable membrane 3 joined to the opening peripheral portion 12a so as to cover the opening 12. As shown in FIG. 3, the exterior sheet 2 is a laminated body configured by laminating at least an outer layer 21, a metal foil layer 22, and an inner layer 23. In the example shown in FIG. 3, an adhesive layer 24 for laminating is provided between the metal foil layer 22 and the inner layer 23. The opening 12 for oxygen uptake is provided so as to penetrate the outer layer 21, the metal foil layer 22, the adhesive layer 24 and the inner layer 23. The oxygen permeable membrane 3 is bonded to the inner layer side of the exterior sheet 2.

  More specifically, the exterior sheet 2 is provided with an annular inclined portion 12b that protrudes toward the exterior by pressing and an opening peripheral portion 12a that is connected to the inclined portion 12b. The opening 12 is an opening portion. It is surrounded by the peripheral part 12a. And the oxygen permeable film 3 is joined to the inner layer side of the opening peripheral part 12a over the perimeter of the opening peripheral part 12a. The oxygen permeable membrane 3 is larger than the opening 12, and the portion protruding from the opening 12 is an outer edge 3 a of the oxygen permeable membrane 3, and this outer edge 3 a is bonded to the inner layer side of the opening peripheral 12 a. Has been.

  Moreover, the silane coupling agent which has a reactive functional group is apply | coated to the joint surface of any one or both of the outer edge part 3a of the oxygen permeable film 3, or the opening peripheral part 12a over the perimeter. Furthermore, a silane treatment agent having a hydrophobic functional group may be applied to the oxygen permeable membrane 3.

  As a mode of joining the oxygen permeable membrane 3 to the opening peripheral portion 12a, the opening peripheral portion 12a and the oxygen permeable film 3 may be pressure-bonded and bonded between the opening peripheral portion 12a and the oxygen permeable film 3. Layers may be formed and bonded.

Further, the outer sheet 2 is provided with an annular inclined portion 12b and an opening peripheral portion 12a, and the oxygen permeable membrane 3 is joined to the opening peripheral portion 12a, whereby the recess 1a is formed on the inner layer side of the outer covering material 1. Is provided. The recess 1a accommodates a negative electrode, an air electrode, and the like of the air secondary battery.
Hereinafter, the constituent members of the exterior material 1 will be described in detail.

(Exterior sheet)
As described above, the exterior sheet 2 is configured by laminating the outer layer 21, the metal foil layer 22, and the inner layer 23. An adhesive layer 24 is interposed between the inner layer 23 and the metal foil layer 22. Further, an adhesive layer (not shown) is interposed between the outer layer 21 and the metal foil layer 22.

<Outer layer>
The outer layer 21 includes at least one or two or more heat resistant resin films. When the outer layer 21 is composed of two or more heat resistant resin films, the heat resistant resin films are preferably laminated with an adhesive layer interposed therebetween.

  The heat resistant resin film constituting the outer layer 21 plays a role of ensuring moldability when the recess 1a is formed in the exterior material 1, and a stretched film of polyamide (nylon) resin or polyester resin is preferably used. The melting point of the heat resistant resin film constituting the outer layer 21 is preferably higher than the melting point of the thermoplastic resin film constituting the inner layer 23. Thereby, it becomes possible to perform the heat seal of the exterior material 1 at the time of manufacturing an air secondary battery reliably.

  The thickness of the outer layer 21 is preferably about 10 to 50 μm, and more preferably about 15 to 30 μm. If the thickness is 10 μm or more, the stretch of the stretched film will not be insufficient when the outer packaging material 1 is molded, necking will not occur in the metal foil layer 22, and molding defects will not occur. Moreover, if thickness is 50 micrometers or less, the effect of a moldability can fully be exhibited.

<Metal foil layer>
The metal foil layer 22 plays the role of ensuring the barrier property of the exterior material 1. As the metal foil layer 22, an aluminum foil, a stainless steel foil, a copper foil, or the like is used. In consideration, it is preferable to use an aluminum foil. As the material of the aluminum foil, a pure aluminum-based or aluminum-iron-based alloy O material (soft material) is preferably used.

  The thickness of the metal foil layer 22 needs to be 20 to 80 μm in order to ensure workability and to ensure barrier properties that prevent oxygen and moisture from entering the air secondary battery. When the thickness is 20 μm or more, the metal foil layer 22 is not broken during the molding of the outer packaging material 1, and no pinhole is generated, so that intrusion of oxygen and moisture can be prevented. Moreover, if the thickness is 80 μm or less, the effect of improving the fracture during molding and the effect of preventing the occurrence of pinholes are maintained, and the total thickness of the exterior material 1 is not excessively increased, preventing an increase in weight, The volume energy density of the secondary battery can be improved.

  In addition, the metal foil layer 22 is subjected to an undercoat treatment with a silane coupling agent or a titanium coupling agent, a chromate treatment, or the like in order to improve the adhesion with the outer layer 21 and the inner layer 23 or to improve the corrosion resistance. A chemical conversion treatment should be performed.

<Inner layer>
Next, the inner layer 23 includes a thermoplastic resin film. As the thermoplastic resin film used for the inner layer 23, it plays a role of improving chemical resistance against an electrolyte for an air secondary battery having heat sealability and high corrosivity, and the metal foil layer 22 Those that can ensure insulation from the air electrode or negative electrode of the air secondary battery are good. For example, unstretched polyolefin films such as polypropylene and maleic acid-modified polypropylene, and unstretched films such as ethylene-acrylate copolymer or ionomer resin Is preferably used.
In particular, the inner layer 23 is preferably an acid-modified polyolefin film, more preferably a carboxylic acid-modified polyolefin film, such as maleic anhydride-modified polyethylene or maleic anhydride-modified polypropylene. By using an acid-modified polyolefin film for the inner layer 23 and applying a silane coupling agent to the inner layer 23 or the oxygen permeable membrane 3, the bonding strength of the oxygen permeable membrane 3 can be further increased.

  As thickness of the inner layer 23, the range of 0.1-200 micrometers is preferable, and the range of 50-100 micrometers is more preferable. If the thickness is 0.1 μm or more, preferably 50 μm or more, the heat seal strength is sufficient, the corrosion resistance to the electrolyte and the like is improved, and the insulation between the metal foil layer 22 and the negative electrode is enhanced. Moreover, if thickness is 200 micrometers or less, Preferably it is 100 micrometers or less, there is no trouble in heat-sealing property and chemical-resistance, and the volume energy density of an air secondary battery can be improved.

  Further, the thermoplastic resin film constituting the inner layer 23 may be composed of a single thermoplastic resin layer, or may be composed of a laminate of a plurality of thermoplastic resin layers. Specific examples of the inner layer composed of a plurality of thermoplastic resin layers include, for example, a three-layer film comprising an intermediate layer and a pair of coating layers laminated on both sides in the thickness direction of the intermediate layer with the intermediate layer interposed therebetween. it can.

  The melting point of the thermoplastic resin film constituting the inner layer 23 is preferably in the range of 130 ° C to 170 ° C, and more preferably in the range of 160 to 165 ° C. When the melting point is within this range, the heat resistance of the inner layer 23 is improved, the thickness of the inner layer 23 during heat sealing is not reduced, and the insulating property of the inner layer 23 is improved.

<Adhesive layer>
The adhesive layer 24 for laminating is disposed between the inner layer 23 and the metal foil layer 22 in order to bond the inner layer 23 and the metal foil layer 22. An adhesive layer is also disposed between the outer layer 21 and the metal foil layer 22.
The adhesive layer is preferably a dry laminate adhesive layer. For example, at least one selected from urethane-based, acid-modified polyolefin, styrene elastomer, acrylic-based, silicone-based, ether-based, and ethylene-vinyl acetate-based materials can be used. .

  The thickness of the adhesive layer is preferably in the range of 0.1 to 10 μm, and more preferably in the range of 1 to 5 μm. If the thickness of the adhesive layer is 1 μm or more, the adhesive strength does not decrease, and the insulation of the inner layer 23 can be further enhanced on the inner layer side. Moreover, if the thickness of an adhesive layer is 5 micrometers or less, the fall of adhesive strength can be prevented.

In particular, it is preferable to use adhesive layers made of different materials for the outer layer-side adhesive layer and the inner layer-side adhesive layer 24. As a combination of materials for the adhesive layer, a urethane adhesive is preferably used as an adhesive on the outer layer side when the outer layer 21 is made of PET or nylon, and an inner layer is formed when the inner layer 23 is made of polypropylene or acid-modified polypropylene. An acrylic adhesive or an acid-modified olefin adhesive may be used as the side adhesive.
By using adhesive layers made of different materials as the outer-layer-side adhesive layer and the inner-layer-side adhesive layer 24, it is possible to impart adhesive strength and resistance to electrolyte solution between the respective materials.

  The inner layer 23 and the metal foil layer 22 may be laminated through the adhesive layer 24 as in the case of the outer layer 21, but a thermoadhesive resin excellent in chemical resistance and electrolytic solution resistance is used. In this case, better adhesion can be obtained between the inner layer 23 and the metal foil layer 22. In this case, a heat-adhesive resin such as maleic anhydride-modified polypropylene modified with maleic anhydride or the like is extruded between the metal foil layer 22 and the inner layer 23 and heat laminated. The method of heat laminating the metal foil layer 22 and the modified polypropylene, and the inner layer and the polypropylene by using a co-extruded resin of the same type as the thermoplastic resin film of the inner layer 23, for example, polypropylene and modified polypropylene resin, is costly. Is superior to.

(Oxygen permeable membrane)
The oxygen permeable membrane 3 allows oxygen to pass between the outside air and the air electrode of the air secondary battery. The thickness of the oxygen permeable membrane 3 is preferably in the range of 0.1 to 500 μm, and more preferably in the range of 10 μm to 100 μm. The material of the oxygen permeable membrane 3 is an anion exchange membrane, and examples thereof include any one selected from the group consisting of a sulfo ion exchange resin, a fluorine ion exchange resin, and a strongly basic negative ion exchange resin. Of these, sulfo ion exchange resins are preferred.

(Silane coupling agent having a reactive functional group)
A silane coupling agent having a reactive functional group (hereinafter referred to as a silane coupling agent) modifies the bonding surface of the outer edge portion 3a of the oxygen permeable membrane 3 or the peripheral portion 12a of the opening portion of the exterior sheet 2 so as to transmit oxygen. The bonding strength between the film 3 and the exterior sheet 2 is improved. While the bonding surface of the oxygen permeable membrane 3 has polarity, the inner layer of the outer sheet 2 has hydrophobicity, and the surface properties are greatly different, so that a silane coupling agent is applied to improve the bonding strength. Is extremely effective. The reactive functional group of the silane coupling agent has a polar group at the terminal, and the bonding strength between the oxygen permeable film 3 and the exterior sheet 2 is improved by bonding the polar group to the oxygen permeable film 3. It is considered a thing. When the oxygen permeable film 3 and the exterior sheet 2 are bonded together, a silane coupling agent may be applied to either the oxygen permeable film 3 or the exterior sheet 2.

Examples of the polar group at the end of the reactive functional group of the silane coupling agent include a vinyl group, an epoxy group, a styryl group, a methacryl group, an acrylic group, an amino group, a ureido group, a mercapto group, a sulfide group, and an isocyanate group. Any one selected from the group which can be illustrated.
In order to improve the bonding strength, the coated amount of the silane coupling agent is preferably to 0.1 mg / ^{m 2} or more 10000 mg / ^{m 2} or less in the range, 0.1 mg / ^{m 2} or more 100 mg / m A range of ² or less is more preferable, and a range of 0.5 mg / m ² or more and 1 mg / m ² or less is particularly preferable.

  Specific examples of the silane coupling agent include vinyl silane, methacryl silane, epoxy silane, mercapto silane, sulfur silane, amino silane, ureido silane, and isocyanate silane.

(Silane coupling agent having a hydrophobic functional group)
Moreover, in the exterior material 1 which is a preferable aspect of the present embodiment, a silane treatment agent having a hydrophobic functional group (hereinafter, referred to as “bonding surface”) on the outer edge portion 3a of the oxygen permeable membrane 3 or the opening peripheral portion 12a of the exterior sheet 2 Or a hydrophobic silane treating agent). By applying a hydrophobic silane treatment agent, hydrophobic groups are introduced into the surface of the joint surface, which prevents moisture from entering the joint surface and into the air secondary battery via the joint portion. Intrusion of moisture can be suppressed and the bonding strength can be increased. In addition, by applying a silane coupling agent having a hydrophobic functional group to the oxygen permeable membrane 3, it is possible to prevent the oxygen permeable membrane 3 from being swollen by contact with the electrolyte solution, so that good oxygen permeability can be obtained. It becomes possible. Further, a hydrophobic silane treating agent may be applied to the entire oxygen permeable membrane 3. Thereby, the penetration | invasion of the water | moisture content in an air secondary battery is suppressed.

Examples of the hydrophobic functional group of the hydrophobic silane treating agent include an alkyl group having 1 or more carbon atoms and having a cyclic, linear or branched chain.
The coating amount of the hydrophobic silane treatment agent is preferably to 0.1 mg / ^{m 2} or more 10000 mg / ^{m 2} or less in the range, be 0.1 mg / ^{m 2} or more 100 mg / ^{m 2} or less of the range More preferably, the range of 0.5 mg / m ^{2 to} 1 mg / m ² is particularly preferable.

  Specific examples of the hydrophobic silane treating agent include chlorosilane, alkoxysilane, silazane and the like.

(Adhesive layer)
Examples of the adhesive when the oxygen permeable membrane 3 and the exterior sheet 2 are bonded together include urethane, acid-modified polyolefin, styrene elastomer, acrylic, silicone, ether, ethylene-vinyl acetate, and the like. .

  In order to ensure sufficient adhesive strength, the thickness of the adhesive layer is preferably in the range of 0.05 μm to 100 μm, and more preferably in the range of 0.1 μm to 5 μm.

[Method of manufacturing exterior material for air secondary battery]
Next, the manufacturing method of the exterior material 1 is demonstrated.
The manufacturing method of the exterior material 1 which is a preferable aspect of the present embodiment is that silane coupling is performed on the bonding surface of one or both of the opening peripheral portion 12a of the exterior sheet 2 and the outer edge portion 3a of the oxygen permeable membrane 3. A step of applying the agent, and a step of bonding the oxygen permeable membrane 3 to the opening peripheral portion 12a of the exterior sheet 2.
Alternatively, a hydrophobic silane treatment agent may be applied to the oxygen permeable membrane 3 before and after applying the silane coupling agent.

  As the step of applying the silane coupling agent, for example, the silane coupling agent is dispersed in a solvent to form a dispersion, and this dispersion is applied to the opening peripheral portion 12a or the outer edge 3a of the oxygen permeable membrane 3, or The outer sheet 2 or the oxygen permeable membrane 3 is immersed in this dispersion, and then the solvent is removed by heating.

  In addition, as the step of applying the hydrophobic silane treating agent, for example, the hydrophobic silane treating agent is dispersed in a solvent to form a dispersion, and this dispersion is applied to the oxygen permeable membrane 3 or oxygen permeable to this dispersion. The film 3 is immersed, and then the solvent is removed by heating.

  The order in which both the silane coupling agent and the hydrophobic silane treating agent are applied to the oxygen permeable membrane 3 may be performed first, but preferably the hydrophobic silane treating agent is applied first.

  In addition, when a silane coupling agent or a hydrophobic silane treatment agent is applied to the oxygen permeable film 3, the pores around the oxygen permeable film 3 can be increased by the silane coupling agent by increasing the application time or immersion time. May be occluded. In particular, the silane coupling agent can be uniformly applied by applying the silane coupling agent after closing the pores in the peripheral portion with the hydrophobic silane treatment agent.

  Next, when joining the opening peripheral portion 12a of the exterior sheet 2 and the oxygen permeable membrane 3 by thermocompression bonding, for example, the pressure-compression starting pressure is set to 0 to 4 MPa, the pressure-bonding pressure is set to 2 to 8 MPa, and the pressure-bonding temperature is set. Is in the range of 70 to 220 ° C., and the crimping time is preferably in the range of 10 seconds to 3 minutes. By setting the pressure start pressure to 0 to 4 MPa, it is possible to prevent the oxygen permeable membrane 3 from cracking. Further, the bonding strength can be sufficiently increased by setting the pressure bonding pressure to 2 to 8 MPa, the pressure bonding temperature to 70 to 220 ° C., and the pressure bonding time to 10 seconds to 3 minutes.

  Moreover, when joining the opening peripheral part 12a of the exterior sheet 2 and the oxygen permeable film 3 by adhesion, for example, an acrylic adhesive or an acid-modified olefin adhesive is applied to the adhesive surface and dried. Can be glued.

  4 and 5 show an air secondary battery using the above-described exterior material 1. The air secondary battery shown in FIGS. 4 and 5 is a lithium air secondary battery using lithium as a negative electrode active material.

  A lithium air secondary battery 31 shown in FIG. 4 includes an air electrode 32, a negative electrode 33, an electrolyte, and at least an exterior material 1 and 34 for packaging the air electrode 32, the negative electrode 33, and the electrolyte. The packaging material 1 is disposed on the air electrode 32 side, and the oxygen permeable membrane 3 joined to the packaging material 1 is superimposed on the air electrode 32. The air electrode 32 is connected to the air electrode lead 32a. The air electrode lead 32a protrudes outside the exterior materials 1 and 34 as a positive electrode terminal. Further, the exterior material 34 is disposed on the negative electrode 33 side. The battery exterior material 34 is formed of the same laminate as the exterior sheet 2 constituting the exterior material 1. The outer peripheral portions 1b and 34b on the inner layer side of the outer packaging materials 1 and 34 are heat-sealed with each other to form a substantially bag shape. The air electrode 32, the negative electrode 33, and the electrolyte are inserted between the exterior materials 1 and 34 and are disposed in the recess 1 a of the exterior material 1. Moreover, a separator is arrange | positioned between the air electrode 32 and the negative electrode 33 as needed.

  The air electrode 32 is configured by laminating a catalyst layer and an oxygen diffusion layer. The oxygen diffusion layer diffuses oxygen that has permeated through the opening 12 and the oxygen permeable film 3 over the entire surface of the catalyst layer. The catalyst layer takes in oxygen and causes an electrode reaction.

  The negative electrode 33 is made of, for example, a metal lithium foil. The negative electrode 33 is pressure-bonded to a current collector 35 made of metal or the like. The current collector 35 is connected to the negative electrode lead 36. The negative electrode lead 36 protrudes outside the exterior materials 1 and 34 as a negative electrode terminal.

  When the lithium air secondary battery 31 shown in FIG. 4 is manufactured, the outer packaging materials 1 and 34 are prepared and heat-sealed to form a bag body, and the current collector 35 and the negative electrode lead 36 are integrated with the negative electrode 33. The separator 33 and the air electrode 32 are superimposed on the negative electrode 33, and the negative electrode 33, the separator, and the air electrode 32 are inserted into the recess 1a of the outer package 1 from the opening of the bag body, and finally the electrolyte is injected. The lithium air secondary battery 31 is obtained by heat-sealing the opening.

5 includes at least an air electrode 42, a negative electrode 43, an electrolyte, an air electrode 42, a negative electrode 43, and an exterior material 1, 1 for packaging the electrolyte. Yes.
In the example shown in FIG. 5, current collectors 45, 45, negative electrodes 43, 43 made of metal lithium foil, and air electrodes 42, 42 are sequentially stacked on both surfaces of the negative electrode lead 46. In addition, the air electrode leads 42a are overlapped and heat-sealed so as to sandwich the air electrode lead 42a.

  When the lithium air secondary battery 41 shown in FIG. 5 is manufactured, the outer packaging materials 1 and 1 are prepared and heat-sealed to form a bag body, and the current collector 45 and the negative electrode lead 46 are integrated with the negative electrode 43. The separator 43 and the air electrode 42 are superposed on the negative electrode 43, and the negative electrode 43, the separator, and the air electrode 42 are inserted into the recesses 1a and 1a of the exterior materials 1 and 1 from the opening of the bag body, and finally the electrolyte is injected. Lithium-air secondary battery 41 is obtained by heat-sealing the opening after liquid.

  In the examples shown in FIGS. 4 and 5, the lithium air secondary battery has been described as an example. However, the present invention is not limited to this, and is applied to, for example, an aluminum air secondary battery in which the negative electrode active material is aluminum. Also good.

As described above, according to the air secondary battery exterior material 1 that is a preferred aspect of the present embodiment, when the inner layer 23 including the thermoplastic resin film and the oxygen permeable membrane 3 are joined, the inner layer 23 or oxygen Since the silane coupling agent is applied to at least one of the permeable membranes 3, the bonding strength between the inner layer 23 and the oxygen permeable membrane 3 is improved, the resistance to the electrolyte is increased, and the oxygen permeable membrane 3 swells. Since oxygen can be suppressed, oxygen permeability is improved.
Further, by applying a hydrophobic silane treatment agent to the oxygen permeable membrane 3, moisture permeation through the oxygen permeable membrane 3 can be prevented. In addition, it is possible to prevent moisture from adhering to the outer edge portion 3a of the oxygen permeable film 3 that has been hydrophobized by the hydrophobic silane treatment agent, thereby further improving the bonding strength between the inner layer 23 and the oxygen permeable film 3.

  Moreover, according to the air secondary battery which is a preferable aspect of the present embodiment, since the air secondary battery exterior material 1 with improved bonding strength between the inner layer 23 and the oxygen permeable membrane 3 is provided, electrolyte leakage and , It is possible to prevent the intrusion of carbon dioxide from the outside, and it is possible to prevent the life of the air secondary battery from being shortened.

Furthermore, according to the method for manufacturing the air secondary battery outer packaging material 1 which is a preferred aspect of the present embodiment, when the inner layer 23 including the thermoplastic resin film and the oxygen permeable film 3 are joined, the inner layer 23 or the oxygen permeable film is bonded. Since the silane coupling agent is applied to at least one of the membranes 3, the bonding strength between the inner layer 23 and the oxygen permeable membrane 3 is improved, the resistance to the electrolyte is increased, and the oxygen permeable membrane 3 can be prevented from swelling. Therefore, good oxygen permeability can be realized.
Further, by applying a hydrophobic silane treatment agent to the oxygen permeable film 3, moisture permeation through the oxygen permeable film 3 can be prevented and the bonding strength between the inner layer 23 and the oxygen permeable film 3 can be further improved.

Example 1
First, commercially available Nafion (registered trademark: ion exchange membrane, size: 5 cm × 3 cm × 0.1 mm) was prepared as an oxygen permeable membrane.

  Next, the oxygen permeable membrane was subjected to a hydrophobic treatment. At this time, an oxygen permeable membrane and 5 ml of tetraethylorthosilicate were placed in an autoclave container, and heated in a sealed state at 100 ° C. for 3 hours. By this operation, a silica film was formed on the surface of the oxygen permeable film made of Nafion film, and hydrophobicity was expressed.

Next, a silane coupling agent is applied to an outer sheet made of an aluminum laminate film as shown in FIG. 1 in which an outer edge portion of the oxygen permeable membrane subjected to the hydrophobic treatment and an opening are formed in advance and a recess is formed. Thus, affinity was expressed between the two. First, a silane coupling agent solution was prepared. The silane coupling agent solution was prepared by diluting an epoxy silane coupling agent having a reactive functional group whose terminal is an epoxy group (Z-6043 manufactured by Dowcorning) to 1% and 5% with ethanol. And using the brush, the silane coupling agent solution was apply | coated to the outer edge part of an oxygen permeable film, and the inner layer side of the opening peripheral part of an exterior sheet. After coating, drying was performed in an oven at 60 ° C. for 1 minute to remove the solvent (ethanol) used for dilution. The coating amount was 1 mg / m ² .

Then, after removing the solvent, the oxygen permeable membrane and the exterior sheet were pressure-bonded using a heat sealer. The pressure bonding conditions were such that the outer layer side of the exterior sheet was 200 ° C., the inner layer side was 100 ° C., the sealing pressure was 9 kgf / cm ² (0.88 MPa), and the sealing time was 1 minute. Thus, the exterior material was manufactured.

(Example 2)
An exterior material was produced in the same manner as in Example 1 except that 3-aminopropyltriethoxysilane (hereinafter referred to as APS) manufactured by Aldrich was used as the silane coupling agent.

(Comparative example)
An exterior material was produced in the same manner as in the example except that the surface treatment with a silane coupling agent and tetraethylorthosilicate was not performed on the oxygen permeable membrane.

(Example 3)
An exterior material was produced in the same manner as in Example 1 except that hydrophobization with tetraethylorthosilicate was not performed.

About the obtained exterior material, peeling strength of an oxygen permeable film and an exterior sheet was evaluated. As conditions, the peel strength was evaluated after the exterior material was immersed in water for 24 hours and after being immersed in an electrolyte solution for 24 hours, in addition to the condition where no stress was applied. The peel strength was measured based on JIS K 6854-2 under the condition that the oxygen permeable membrane was fixed. That is, the exterior sheet to which the ceramic layer was bonded was cut to a width of 15 mm and evaluated by performing a peel test between the ceramic layer and the exterior sheet.
In addition, the above-mentioned immersion in water is ion-exchanged water, and immersion in an electrolytic solution is a non-aqueous electrolytic solution. 1 mol / L LiPF ₆ is mixed in a mixed solvent of ethylene carbonate: diethyl carbonate = 1: 1 (volume ratio). The dissolved electrolyte was used.
The evaluation results are shown in Table 1 below.

  As shown in Table 1 below, the performance with the silane coupling agent was not significantly reduced as compared with the case without the silane coupling agent.

In addition, as shown in FIG. 4, the outer packaging material 1 and the outer packaging material 34 are heat sealed to each other to produce a bag body, and the bag body is filled with a nonaqueous electrolyte solution to which a staining solution is added and sealed. Prepared and evaluated the presence or absence of leakage.
The electrolyte solution was dyed by using a 1 wt% rhodamine B ethanol solution and adding 1 vol% thereof to the electrolyte solution. As the electrolytic solution, an electrolytic solution in which 1 mol / L LiPF ₆ was dissolved in a mixed solvent of ethylene carbonate: diethyl carbonate = 1: 1 (volume ratio) was used.

  The results of the presence or absence of occurrence of liquid leakage are shown in Table 2 below. No leakage of the electrolytic solution was confirmed even after 30 days for those with a silane coupling agent. On the other hand, in the comparative example, liquid leakage occurred in one day. Moreover, in Example 3, the generation | occurrence | production of the gas resulting from the permeation | transmission of a water | moisture content occurred, the internal pressure increased, and the phenomenon which a container expand | swells a little was seen.

  Further, a gas permeation test defined in JIS K 71126-1 was performed on the obtained exterior material. Oxygen gas (99.99%) was used as the gas used at this time. The test temperature was room temperature and the differential pressure was 100 kPa (supply side: 100 kPa, transmission side: 0 kPa). Further, as the sample at this time, a gas permeation test was carried out in a form sandwiched between test cells by using the sample used in the above-described electrolyte leakage test with the air electrode side cut out.

The results of the gas permeation test are shown in Table 3 below.
In Table 3 below, the oxygen permeation performance is expressed as a percentage when the oxygen permeability of the untreated Nafion membrane (Comparative Example 1) is 100.

As shown in Table 3, the oxygen permeability of Example 1 and Example 2 tended to be lower than that of Comparative Example 1. This is presumably because the gas permeation path was reduced by the application of the silane coupling agent and hydrophobic silane.
However, it was clear that the application of the silane coupling agent and hydrophobic silica contributed to durability because these sample shapes were maintained even under the conditions in which Comparative Example 1 and Example 3 were destroyed. became.

DESCRIPTION OF SYMBOLS 1 ... Outer packaging material for air secondary batteries, 2 ... Outer sheet, 3 ... Oxygen permeable film, 3a ... Outer edge part of oxygen permeable film, 12 ... Opening part, 12a ... Periphery part of opening part, 21 ... Outer layer, 22 ... Metal foil Layer, 23 ... inner layer, 31, 41 ... air secondary battery.

Claims (13)

An outer layer containing a heat-resistant resin film, a metal foil layer, and an inner layer containing a thermoplastic resin film are laminated, and an opening for oxygen uptake is provided through the outer layer, the metal foil layer, and the inner layer. An exterior sheet,
An oxygen permeable membrane bonded to the inner layer side of the periphery of the opening so as to cover the opening,
An exterior for an air secondary battery, wherein a silane coupling agent having a reactive functional group is applied to one or both of the outer peripheral portion of the oxygen permeable membrane and the peripheral portion of the opening or both. Wood.   The reactive functional group of the silane coupling agent is any selected from the group consisting of vinyl group, epoxy group, styryl group, methacryl group, acrylic group, amino group, ureido group, mercapto group, sulfide group, and isocyanate group. The packaging material for an air secondary battery according to claim 1, which has at least one type thereof.   The exterior material for an air secondary battery according to claim 1 or 2, wherein the inner layer is made of an acid-modified polyolefin resin film.   The oxygen permeable membrane is an anion exchange membrane and is any one selected from the group consisting of a sulfo ion exchange resin, a fluorine ion exchange resin, and a strongly basic negative ion exchange resin. The packaging material for air secondary batteries as described in any one of Claims.   The packaging material for an air secondary battery according to any one of claims 1 to 4, wherein the packaging sheet and the oxygen permeable membrane are pressure-bonded or bonded.   The packaging material for an air secondary battery according to any one of claims 1 to 5, wherein a silane treatment agent having a hydrophobic functional group is further applied to the oxygen permeable membrane.   An air secondary battery comprising the exterior member for an air secondary battery according to any one of claims 1 to 6. An outer layer containing a heat-resistant resin film, a metal foil layer, and an inner layer containing a thermoplastic resin film are laminated, and an opening for oxygen uptake is provided through the outer layer, the metal foil layer, and the inner layer. Applying a silane coupling agent having a reactive functional group to the peripheral portion of the opening of the exterior sheet, or the bonding surface of either or both of the outer edge portions of the oxygen permeable membrane;
Bonding the oxygen permeable membrane to the periphery of the opening of the exterior sheet;
The manufacturing method of the exterior material for air secondary batteries characterized by comprising.   The reactive functional group of the silane coupling agent is any selected from the group consisting of vinyl group, epoxy group, styryl group, methacryl group, acrylic group, amino group, ureido group, mercapto group, sulfide group, and isocyanate group. The manufacturing method of the exterior material for air secondary batteries of Claim 8 which has such 1 type in the terminal.   The method for producing a packaging material for an air secondary battery according to claim 8 or 9, wherein the inner layer is made of an acid-modified polyolefin resin film.   The oxygen permeable membrane is an anion exchange membrane, and is any one selected from the group consisting of a sulfo ion exchange resin, a fluorine ion exchange resin, and a strongly basic negative ion exchange resin. The manufacturing method of the exterior material for air secondary batteries as described in any one.   The method for manufacturing an exterior material for an air secondary battery according to any one of claims 8 to 11, wherein the exterior sheet and the oxygen permeable membrane are pressure-bonded or bonded.   13. The silane coupling agent having a reactive functional group is applied to the oxygen permeable film, and then the silane coupling agent having a reactive functional group is applied. 13. Manufacturing method for an air secondary battery exterior material.

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