JP2020038793A - Metal air battery - Google Patents

Abstract

To provide a metal air battery that can be easily manufactured and has a positive electrode capable of ensuring a larger number of air inflow paths.SOLUTION: A metal air battery 100A has a first positive electrode 1, a first electrolyte 3, and a first negative electrode complex 2 including a negative electrode, a protective layer, and an isolation layer stacked in this order. The first positive electrode 1 has a cross-sectional structure including a plurality of concave parts, a plurality of convex parts, or the combination of a plurality of concave parts and a plurality of convex parts.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a metal-air battery.

  A metal-air battery uses metal lithium or the like as a negative electrode active material and uses oxygen in the air as a positive electrode active material, has a high energy density, and is required for full-scale spread of EVs (electric vehicles). It is expected as a battery that can obtain energy of the order of 500 Wh / kg.

  In a metal-air battery, at the time of discharge, oxygen and water in the air react with each other at the positive electrode to cause generation of hydroxide ions. Therefore, in order to obtain high electric energy, it is necessary to bring air into contact with the positive electrode surface with high efficiency.

  For example, Patent Literature 1 discloses a positive electrode battery in which a region in which air can be held is increased by bending the positive electrode to increase the reactivity of the positive electrode.

  Further, in Patent Document 2, by providing holes for gas flow passages in the positive electrode base material, even if the separator and the negative electrode structure are laminated, the positive electrode active material composed of air or oxygen gas can be efficiently used as the positive electrode material. A thin lithium-air battery having a thin cathode structure that can be supplied is disclosed.

  Further, Patent Document 3 discloses that after a negative electrode metal layer, a negative electrode electrolyte layer, and a positive electrode layer are laminated, a gas diffusion layer is laminated so as to cover a part of the positive electrode layer. There is disclosed a metal-air battery in which air is supplied to a positive electrode layer with high efficiency by folding a laminate of a negative electrode metal layer, a negative electrode electrolyte layer, and a positive electrode layer so as to cover one side surface with a positive electrode layer. The gas diffusion layer is made of, for example, carbon paper such as carbon fiber, carbon cloth or carbon felt, metal foam such as sponge-shaped metal, or metal fiber mat.

JP2018-37369A JP 2013-73765 A US Patent Publication No. 2015/0144042

  However, although the positive electrode of the air battery of Patent Literature 1 is configured to expand the air flow path by bending, the area of the positive electrode surface is not much different from that of a planar positive electrode, and the positive electrode contacts air. Efficiency is not expected to increase significantly. In addition, the positive electrode substrate of the metal-air battery of Patent Document 2 has a complicated structure and needs to be obtained by a dense manufacturing process using a dry etching method. Further, the production of the metal-air battery of Patent Literature 3 requires a complicated process of folding after manufacturing a laminate of a negative electrode metal layer, a negative electrode electrolyte layer, and a positive electrode layer.

  Therefore, an object of the present invention is to provide a metal-air battery having a positive electrode that can be easily manufactured and that can secure a greater number of air inflow paths.

  In order to achieve the above object, a metal-air battery according to the present invention includes a first positive electrode, a first electrolyte, a first negative electrode composite including a negative electrode, a protective layer, and an isolation layer. The first positive electrode is stacked in order, and has a cross-sectional structure including a plurality of concave portions, a plurality of convex portions, or a combination of a plurality of concave portions and a plurality of convex portions.

  In the metal-air battery according to the present invention, it is preferable that a second electrolyte is laminated on a surface of the first positive electrode opposite to a surface on which the first electrolyte is laminated.

  In the metal-air battery according to the present invention, it is preferable that a second negative electrode composite is laminated on a surface of the second electrolyte opposite to a surface on which the first positive electrode is laminated.

  In the metal-air battery according to the present invention, a third electrolyte is stacked on a surface of the second negative electrode composite opposite to a surface on which the second electrolyte is stacked, and a third electrolyte is formed. A second positive electrode is laminated on a surface opposite to a surface on which the second negative electrode composite is laminated, and the second positive electrode has a plurality of concave portions, a plurality of convex portions, or a plurality of concave portions; It is preferable to have a cross-sectional structure including a combination of a plurality of convex portions.

  In the metal-air battery according to the present invention, preferably, the plurality of recesses, the plurality of protrusions, or the combination of the plurality of recesses and the plurality of protrusions has a shape selected from a rectangle, a triangle, and a curve. . In the metal-air battery according to the present invention, as for the combination of the plurality of concave portions and the plurality of convex portions, it is preferable that one concave portion and one convex portion are arranged at the same position on the front and back, and a plurality of these are combined.

  In the metal-air battery according to the present invention, it is preferable that the plurality of recesses, the plurality of protrusions, or the combination of the plurality of recesses and the plurality of protrusions are arranged in a lattice pattern on the plane of the positive electrode.

  In the metal-air battery according to the present invention, the protective layer preferably covers the negative electrode, and the isolation layer is preferably located between the protective layer and the first electrolyte.

  In the metal-air battery according to the present invention, the first positive electrode preferably includes a positive electrode current collector and a positive electrode material, and the positive electrode current collector preferably includes a metal mesh.

  According to the metal-air battery according to the present invention, the cross-sectional structure of the positive electrode includes a plurality of concave portions, a plurality of convex portions, or a combination of a plurality of concave portions and a plurality of convex portions, so that compared to a planar positive electrode, air Since the number of channels can be increased and the contact area with air can be increased, the charge / discharge performance can be improved. Further, only the positive electrode needs to be formed into such a cross-sectional shape, and the conventional technology can be used for other components of the metal-air battery such as the negative electrode composite and the electrolyte. The positive electrode can also be easily manufactured because it can be obtained only through a simple manufacturing process such as press working. In this way, since only the positive electrode itself is processed and no additional member is required, it is possible to suppress an increase in the cost and man-hours required for manufacturing the metal-air battery while almost maintaining the weight of the metal-air battery. . That is, according to the present invention, there is provided a metal-air battery having a positive electrode that can be easily manufactured and that can secure a greater number of air inflow paths.

  Further, even if the second electrolyte is laminated on the surface of the first positive electrode opposite to the surface on which the first electrolyte is laminated, the positive electrode has the above-described cross-sectional structure. A larger number can be secured, and it can be avoided that the conventional flat cathode cannot contact air and the battery performance is significantly reduced. Therefore, even if the second negative electrode composite is further laminated on the surface of the second electrolyte opposite to the surface on which the first positive electrode is laminated, battery performance such as charging voltage and cycle characteristics is impaired. Instead, a metal-air battery in which a plurality of cells are stacked can be provided. The above-described cross-sectional structure of the positive electrode has a structure in which the third electrolyte is laminated on the surface of the second negative electrode composite opposite to the surface on which the second electrolyte is laminated, and the second electrolyte is formed of the second electrolyte. By adopting the second positive electrode also when the second positive electrode is laminated on the surface opposite to the surface on which the negative electrode composite is laminated, the size of the cell and the size of the cell when it is modularized The degree of freedom can be improved.

  Further, the plurality of recesses, the plurality of protrusions, or the combination of the plurality of recesses and the plurality of protrusions may have one shape selected from a rectangle, a triangle, and a curve, whereby the surface of the positive electrode However, since it has a shape that repeats the same shape, the area of one positive electrode that comes into contact with air and the area that comes into contact with the electrolyte have regularity, and stable battery performance can be achieved.

  Since the protective layer covers the negative electrode and the isolation layer is located between the protective layer and the first electrolyte, the negative electrode composite can protect the metal negative electrode. The used air battery can be provided. In addition, the first positive electrode includes a positive electrode current collector and a positive electrode material, and the positive electrode current collector is formed of a metal mesh, unlike the case where the positive electrode current collector is a metal foil. A sectional structure including a plurality of concave portions, a plurality of convex portions, or a combination of a plurality of concave portions and a plurality of convex portions can be easily formed on the positive electrode by press working. In addition, a mold having a high degree of freedom according to the flow rate and direction of air can be created.

FIG. 1 shows a cross-sectional view of one embodiment of the metal-air battery according to the present invention. FIG. 2 shows a cross-sectional view of another embodiment of the metal-air battery according to the present invention. 3A to 3E are cross-sectional views of an embodiment of the positive electrode in the metal-air battery according to the present invention. FIG. 4A is a cross-sectional view of still another embodiment of the positive electrode in the metal-air battery according to the present invention, FIG. 4B is a plan view of the positive electrode, and FIG. FIG. 2 is a schematic diagram illustrating a method for manufacturing the positive electrode. FIG. 5 shows a cross-sectional view of one embodiment of the single-sided negative electrode composite in the metal-air battery according to the present invention. FIG. 6 shows a cross-sectional view of one embodiment of a double-sided negative electrode composite in a metal-air battery according to the present invention.

  Hereinafter, embodiments of the metal-air battery according to the present invention will be described. However, the present invention is not limited by the embodiments described below. The description of each configuration (a positive electrode, an electrolyte, a negative electrode composite, a negative electrode, a separator, a film, a metal laminate film, an electrolytic solution in the negative electrode composite, and the like) in the metal-air battery of the present embodiment is limited to the illustrated metal-air battery. However, the present invention can be widely applied to the metal-air battery according to the present invention.

[Metal-air battery]
An embodiment of the metal-air battery according to the present invention can be described with reference to, for example, FIG. 1, the metal-air battery 100A has a structure in which a first positive electrode 1, a first electrolyte 3, and a first negative electrode composite 2 are sequentially stacked.

  As another embodiment of the metal-air battery according to the present invention, the stacked structure shown in FIG. 1 may be a single cell and a structure in which a plurality of cells are stacked. For example, as shown in FIG. 2, the metal-air battery 100B includes a first negative electrode composite 2A, a first electrolyte 3A, a first positive electrode 1A, a second electrolyte 3B, a second negative electrode composite 2B, The third electrolyte 3C, the second positive electrode 1B, the fourth electrolyte 3D, the third negative electrode composite 2C,..., And the x-th negative electrode composite 2X are sequentially laminated. Each configuration of such metal-air batteries 100A and 100B will be described below.

[Positive electrode]
The positive electrodes in metal-air batteries 100A and 100B according to the present embodiment have a cross-sectional structure including a plurality of recesses, a plurality of protrusions, or a combination of a plurality of recesses and a plurality of protrusions. The plurality of recesses, the plurality of protrusions, or the combination of the plurality of recesses and the plurality of protrusions preferably has one shape selected from a rectangle, a triangle, and a curve. A rectangle or triangle may have a chamfered corner. The triangle is preferably an isosceles triangle, a right triangle, an equilateral triangle, or the like. The curved shape is preferably a sine curve, a circular arc, an elliptical arc, a quadratic curve, or the like.

  Specifically, as an example of the positive electrode in the metal-air battery according to the present embodiment, the structure shown in FIGS. 3A to 3E can be adopted when viewed from the cross-sectional direction of the metal-air battery. For example, in the positive electrode 11 of FIG. 3A, the crimping portion 11a has a cross-sectional structure of a combination of a plurality of concave portions and a plurality of convex portions, the concave portions and the convex portions are both rectangular, and one concave portion and one convex portion. The two convex portions are arranged at the same position on the front and back, and a plurality of them are combined to form a rectangular wave as a whole. In this specification, as shown in FIG. 3A, the cross-sectional structure of the crimping portion 11a of the positive electrode 11 is such that both surfaces of the terminal portion 11b adjacent to the crimping portion 11a are reference planes L and L '. Those that are depressed inward (center side) from the surfaces L and L 'are referred to as concave portions, and those that protrude outward from the reference surfaces L and L' are referred to as convex portions. The recess may be recessed beyond the surface on the opposite side (the reference plane L ′ with respect to the reference plane L), or may be recessed within the thickness of the positive electrode 11 without exceeding it.

  Further, in the positive electrode 12 of FIG. 3B, the plurality of concave portions and the plurality of convex portions are both sinusoidal curves, one concave portion and one convex portion are arranged at the same position on the front and back, and a plurality of them are combined. This has a sinusoidal shape as a whole. In the positive electrode 13 shown in FIG. 3C, each of the plurality of concave portions and the plurality of convex portions is an isosceles triangle, one concave portion and one convex portion are arranged at the same position on the front and back, and a plurality of them are combined. Has a triangular wave shape as a whole. In the positive electrode 14 of FIG. 3D, the plurality of concave portions and the plurality of convex portions are each a right triangle, and one concave portion and one convex portion are arranged at the same position on the front and back, and a plurality of them are combined. , Have a sawtooth shape as a whole. In the positive electrode 15 of FIG. 3E, the plurality of concave portions and the plurality of convex portions are both arcs, and one concave portion and one convex portion are arranged at the same position on the front and back, and a plurality of them are combined. It has a wavy shape as a whole. FIG. 3 shows an embodiment in which the positive electrode has a cross-sectional structure of a combination of a plurality of concave portions and a plurality of convex portions. However, the present invention is not limited to this, and has a cross-sectional structure of only a plurality of concave portions. Alternatively, a cross-sectional structure of only a plurality of convex portions may be used.

  As an example of a method of manufacturing the positive electrodes 11 to 15 shown in FIGS. 3A to 3E, a planar positive electrode current collector is formed by an arbitrary cross-sectional shape (a plurality of rectangles, sine curves, isosceles triangles, Pressing with an upper mold and a lower mold having a right triangle, a curved shape, and the like. The positive electrode material may be supported on the positive electrode current collector before the pressing, or may be supported on the positive electrode current collector after the pressing. Alternatively, after the positive electrode material is supported on the positive electrode current collector after the pressing, the pressing may be performed again using the same mold.

  Further, FIG. 3 shows a case where a plurality of concave portions and a plurality of convex portions are repeatedly arranged only in the direction from the end on the terminal portion 11b side of the crimping portion 11a of the positive electrode 11 to the end on the opposite side. The present invention is not limited to this, and may have a structure in which a plurality of concave portions and a plurality of convex portions are repeatedly arranged only in a direction orthogonal to the above-described direction instead of the above-described direction. As shown in (b), it is possible to have a structure in which a plurality of concave portions and a plurality of convex portions are alternately and repeatedly arranged in a direction orthogonal to the above direction in addition to the above direction. The pattern of the plurality of convex portions 16b of the rectangular wave shape of the positive electrode 16 shown in the cross-sectional view of FIG. 4A is shown by oblique lines in the plan view of FIG. The pattern of the portion of the plane 16a sandwiched between 16b is shown in white. That is, in the present embodiment, as shown in FIG. 4B, the structure of the positive electrode 16 as viewed from the front direction is a structure in which a plurality of concave portions 16a and a plurality of convex portions 16b are arranged in a lattice pattern. .

  An example of a method for manufacturing the positive electrode 16 shown in FIGS. 4A and 4B is shown in FIG. In contrast to the flat cathode current collector 16A shown in FIG. 4C in which the cathode material is carried on the flat cathode current collector, one side of the concave portion or the convex portion extends in the direction from the terminal portion 11b side end to the opposite end. A plurality of cuts 16x (thick lines) having a length are formed, and then vertically pressed by an upper die and a lower die having an arbitrary cross-sectional shape such as a rectangle at a portion A corresponding to the convex portion 16b in FIG. Method.

  The interval between the plurality of convex portions 16b (or the plurality of concave portions) is not particularly limited in the arrangement shown in FIG. 3 or FIG. 4 or other arrangements. For example, the lower limit is 1 mm from the viewpoint of air flow. Or more, more preferably 2 mm or more. The upper limit is preferably 6 mm or less, more preferably 5 mm or less, from the viewpoint of the durability of the positive electrode. The cross-sectional shape of the positive electrode is only a plurality of protrusions, only a plurality of recesses, or a combination of a plurality of recesses and a plurality of protrusions, the height from the top surface to the bottom surface of the cross-sectional shape is not particularly limited, For example, the lower limit is preferably 0.5 mm or more, and more preferably 1 mm or more, from the viewpoint of air circulation. The upper limit is preferably 4 mm or less, more preferably 3 mm or less, from the viewpoint of the durability of the positive electrode.

  The positive electrode in the metal-air battery according to the present invention preferably includes a positive electrode current collector and a positive electrode material. It is preferable that the crimping portion 11a of the positive electrode 11 be made of a positive electrode current collector and a positive electrode material, and the terminal portion 11b of the positive electrode 11 be made of a positive electrode current collector.

  The positive electrode current collector and the positive electrode material are not particularly limited as long as they are materials used in a metal-air battery. Examples of the positive electrode material include platinum, gold, iridium, ruthenium and other noble metals having catalytic activity, oxides thereof, or manganese dioxide having catalytic activity, and carbon having high conductivity as a conductive aid. Polyvinylidene fluoride, polytetrafluoroethylene, styrene-butadiene rubber, or the like can be used as a binder. Examples of the positive electrode current collector include carbon paper, carbon cloth, carbon nonwoven fabric, titanium mesh, nickel mesh, copper mesh, SUS mesh, porous nickel (nickel metal foam), and porous aluminum (aluminum metal foam). ), A metal mesh using a metal having high corrosion resistance such as porous titanium or the like can be used. The positive electrode current collector preferably has excellent conductivity and gas diffusivity. Here, the carbon cloth refers to a cloth-like sheet woven with carbon fiber or the like, and the carbon non-woven fabric is a sheet-like sheet in which carbon fibers are randomly entangled.

  By supporting the positive electrode material on a positive electrode current collector, the pressure-bonded portion 11a of the positive electrode 11 can be formed. The positive electrode material is filled in the mesh of the positive electrode current collector and exists in a film form on both surfaces of the positive electrode current collector. The thickness of the positive electrode current collector is not particularly limited, but, for example, the lower limit is preferably 0.04 mm or more, more preferably 0.1 mm or more, and the upper limit is preferably 0.4 mm or less, more preferably 0.3 mm or less. preferable. The thickness of the positive electrode material film formed on the surface of the positive electrode current collector is not particularly limited. For example, the lower limit is preferably 0.2 mm or more, more preferably 0.4 mm or more, and the upper limit is 1 mm or less. Preferably, it is 0.7 mm or less.

  In the case of using an aqueous electrolyte solution in a metal-air battery, the positive electrode is required to have conductivity, gas diffusion properties, and corrosion resistance to the electrolyte solution. Further, in a metal-air battery, it is necessary to process the positive electrode current collector into an arbitrary shape through which air can pass by press molding. The positive electrode current collector in the metal-air battery according to the present invention is preferably a metal mesh. A metal mesh is a suitable material as a positive electrode current collector because a conductive auxiliary agent and the like are pressed and press-moldable. In particular, titanium mesh is conductive, has high corrosion resistance to alkaline aqueous solutions, is lightweight, is less expensive than precious metals such as platinum and gold, which exhibit high corrosion resistance, and can be press-molded. It is a material that can be preferably used as a positive electrode current collector.

  A positive electrode having a cross-sectional structure including a plurality of concave portions, a plurality of convex portions, or a combination of a plurality of concave portions and a plurality of convex portions as shown in FIGS. 3A to 3E and FIG. Even when a flat electrolyte is laminated on one or both sides, a space through which air can pass is created in the positive electrode, so that the amount of air taken in by the positive electrode increases, and air can be taken in efficiently. Further, since the above-described positive electrode is obtained by pressing a positive electrode material supported on a planar positive electrode current collector into an arbitrary shape, the production is easy.

[Electrolytes]
The electrolyte 3 in the present embodiment is not particularly limited as long as it is an electrolyte used in a metal-air battery. For example, an aqueous electrolyte solution or a non-aqueous electrolyte solution can be used.

The aqueous electrolyte solution only needs to have electrical conductivity, and is preferably an aqueous electrolyte solution in which a lithium salt is dissolved in water. Examples of the lithium salt dissolved in water include LiCl (lithium chloride), LiOH (lithium hydroxide), LiNO ₃ (lithium nitrate), CH ₃ COOLi (lithium acetate), and the like. A liquid dissolved in water can be used.

Examples of the non-aqueous electrolyte include a carbonate-based organic solvent such as propylene carbonate (PC), ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC); ethylene glycol dimethyl ether (EGDME); Examples thereof include ether solvents such as ethylene glycol dimethyl ether and triethylene glycol dimethyl ether. These solvents may be used alone or in a mixed solution. In order to impart conductivity, LiPF ₆ (lithium hexafluorophosphate), LiClO ₄ (lithium perchlorate), LiBF ₄ (lithium tetrafluoroborate), LiTFSI (lithium bis (trifluoromethanesulfonyl) imide), LiFSI (lithium bis (fluorosulfonyl) imide), Li _(SO 2 _{CF 3) 2} can be added (lithium bis (trifluoromethanesulfonyl) imide) and the like.

In addition to the above electrolyte, a solid electrolyte in which a lithium salt is dispersed in a polymer may be used, or a gel electrolyte in which an organic electrolyte in which a lithium salt is dissolved is swollen in a polymer may be used. Examples of the lithium salt include LiPF ₆ , LiClO ₄ , LiBF ₄ , LiTFSI (LiN (SO ₂ CF ₃ ) ₂ ), LiFSI (LiN (SO ₂ F)) ₂ , and LiBOB (lithium bisoxalatoborate). . The polymer serving as the host for the gel electrolyte is PEO (polyethylene oxide), PPO (polypropylene oxide), PVA (polyvinyl alcohol), PAN (polyacrylonitrile), PVP (polyvinylpyrrolidone), PEO-PMA (polyethylene oxide-modified polymethacrylate cross-linking). Body), PVdF (polyvinylidene fluoride), PVA (polyvinyl alcohol), PAA (polyacrylic acid), PVdF-HFP (copolymer of polyvinylidene fluoride and hexafluoropropylene) and the like.

  In addition, as the electrolyte, a material obtained by impregnating a porous body with the above electrolyte may be used. As the porous body, in addition to a porous film such as polyacrylamide, polyethylene, and polypropylene, a nonwoven fabric such as cellulose, a resin nonwoven fabric, and a glass fiber nonwoven fabric, and a hydrogel can be used.

[Negative electrode composite]
The negative electrode composite in the metal-air battery of the present embodiment is not particularly limited as long as it has a negative electrode, a protective layer, and an isolation layer, and a known negative electrode composite can be used. As an example of the negative electrode composite according to the present embodiment, there is a single-sided negative electrode composite 2a shown in FIG. Such a single-sided negative electrode composite 2a can be used for the negative electrode structure 2 shown in FIG. 1, the first negative electrode composite 2A shown in FIG. 2, and the x-th negative electrode composite 2X. The single-sided negative electrode composite 2a includes an isolation layer 40 made of a solid electrolyte between a first metal foil laminated film 20a and a second metal foil laminated film 20b provided at the top and bottom in FIG. It has a laminated structure in which the protective layer 33, the negative electrode 30, and the film 34 are sandwiched. The first metal foil laminated film 20a located on the positive electrode (not shown) side of the metal-air battery has an opening 50 substantially at the center of the plane thereof.

  The first metal foil laminated film 20a having the opening 50 is formed from the inside of the single-sided negative electrode composite 2a from the inside to the outside (from bottom to top in the figure), the first resin layer 21, the metal foil It is a sheet in which three layers are laminated in the order of the layer 22 and the second resin layer 23. Similarly, the second metal foil laminated film 20b also includes a first resin layer 21 and a metal foil layer 22 from the inside to the outside of the single-sided negative electrode composite 2a (from top to bottom in the figure). , A second resin layer 23 in the order of three layers. The peripheral portions of the first metal foil laminated film 20a and the second metal foil laminated film 20b are joined by heat welding.

  An isolation layer 40 is arranged inside the first metal foil laminated film 20a so as to close the opening 50. That is, the size in the plane of the isolation layer 40 is larger than the opening 50 of the first metal foil laminated film 20a, and the peripheral edge of the isolation layer 40 is the inner peripheral edge of the opening 50 of the first metal foil laminated film 20a. It is welded to the part and fixed.

  The ends of the protective layer 33, the negative electrode 30, and the film 34 are sandwiched between the first metal foil laminated film 20a and the second metal foil laminated film 20b having no opening, and are welded and fixed.

  The negative electrode 30 has a structure in which two layers are laminated in this order from a film 34 side, a negative electrode current collector 31 and a negative electrode layer 32 made of metallic lithium. The end of the protective layer 33 is welded to and fixed to the negative electrode current collector 31, so that the negative electrode current collector 31 and the protective layer 33 seal the negative electrode layer 32. Note that the protective layer 33 is not fixed to the negative electrode layer 32.

  As shown in FIG. 5, the negative electrode current collector 31 includes a current collector 31a sandwiched between a film 34 and a negative electrode layer 32, and a first metal foil laminated film 20a and a second metal foil laminated film therefrom. And a terminal portion 31b extending to the outside of 20b. The current collecting portion 31a of the negative electrode current collector 31 has a rectangular shape in a plane, and the terminal portion 31b has a linear shape with a smaller width. The current collector 31 a of the negative electrode current collector 31 is joined to the protective layer 33 so that the entire end portion is covered with the protective layer 33. The film 34 covers the entire back side of the current collector 31 a of the negative electrode current collector 31.

  Further, as shown in FIG. 5, the isolation layer 40 and the protective layer 33 are provided at an interval. An organic electrolyte or the like is sealed in a space between the isolation layer 40, the protective layer 33, and the first metal foil laminated film 20a.

  As another example of the negative electrode composite according to the present embodiment, there is a double-sided negative electrode composite 2b shown in FIG. Such a double-sided negative electrode composite 2b is used for the second negative electrode composite 2B, the third negative electrode composite 2C,..., The (x−1) -th negative electrode composite 2X ′ in FIG. Can be. The double-sided negative electrode composite 2b is a modified example of the single-sided negative electrode composite 2a shown in FIG. 5, and thus a duplicate description will be omitted, and differences will be described. In FIG. 6, the double-sided negative electrode composite 2b includes a negative electrode current collector 31, a negative electrode layer 32, a protective layer 33, an isolation layer 40, and a metal foil laminated film 20a having an opening on both upper and lower surfaces in the figure. It has a structure provided. According to such a configuration, an air battery having a structure in which a positive electrode is disposed on both surfaces of a negative electrode composite can be provided, and an air battery having a structure in which one surface of one positive electrode faces one surface of one negative electrode composite The volume can be reduced as compared with.

[Negative electrode]
The negative electrode 30 of the negative electrode composite according to the present embodiment includes a negative electrode layer 32 and a negative electrode current collector 31, as shown in FIGS.

As the negative electrode active material of the negative electrode layer 32, metals such as lithium and zinc can be used, but lithium is more preferable from the viewpoint of high open-circuit voltage and practicality. Further, the negative electrode active material is not limited to metallic lithium, and may be an alloy or compound containing lithium as a main component. The lithium-based alloy can include magnesium, calcium, aluminum, silicon, germanium, tin, lead, antimony, bismuth, silver, gold, zinc, and the like. Compound mainly containing lithium, for _{example, Li 3-x M x N} (M = Co, Cu, Ni; x = 1,2,3) is.

  The material of the negative electrode current collector 31 may be any material as long as it can exist stably in the operation range of the air battery and has a desired conductivity, and examples thereof include copper and nickel.

When the negative electrode layer is metallic lithium, the negative electrode layer becomes lithium ions (Li ⁺ ) and electrons (e ⁻ ) when the metal-air battery discharges. Then, the lithium ions (Li ⁺ ) are dissolved in the electrolytic solution, and the electrons (e ⁻ ) are supplied to the terminals through the current collector of the negative electrode current collector. Therefore, the design value of the battery capacity can be controlled by changing the thickness and area of the negative electrode layer.

[Protective layer]
The protective layer 33 of the anode composite 2 of the present embodiment is not particularly limited as long as it is a protective layer used in a metal-air battery. For example, it is preferable that the protective layer 33 has a plurality of pores through which ions of a metal such as lithium ions, which is a negative electrode active material, and an organic electrolyte can pass. As such a protective layer 33, for example, a sheet of a porous polyolefin resin such as polyethylene or polypropylene, or a sheet of cellulose or the like used as a separator of a lithium ion battery or the like can be used. In addition to these materials, materials such as aramid having a porous structure, polytetrafluoroethylene, and aluminum oxide having a capillary structure can be used. Further, a sheet in which an organic electrolytic solution is impregnated in a sheet of these materials can be used.

  As the material of the protective layer 33, a material having a porosity of about 40% to 90% and a thickness of about 10 to 300 μm can be used, and a material having a porosity of about 15 to 100 μm can be more preferably used. The size of the holes may be about 20 nm to 500 nm, and more preferably about 20 to 70 nm. Further, it is more preferable that the protective layer itself has some rigidity and strength.

[Isolation layer]
The isolation layer 40 of the anode composite 2 of the present embodiment is not particularly limited as long as it is an isolation layer used in a metal-air battery. For example, the isolation layer 40 is preferably a solid substance that can transmit ions (lithium ions) by applying a voltage. As the solid electrolyte, for example, a non-combustible glass ceramic having excellent lithium ion conductivity can be used. In particular, when an aqueous electrolytic solution is used as the electrolytic solution, a highly water-resistant LATP glass ceramic electrolyte can be used.

[the film]
The film 34 of the negative electrode composite 2 of the present embodiment covers the entire rear surface of the current collector 31 a of the negative electrode current collector 31. The film 34 may be joined on the entire back side of the current collector, or may be joined only on the periphery. Further, the film 34 may cover not only the entire surface of the negative electrode current collector 31 but also the side surface (end portion). As the film 34, for example, a resin sheet or the like that is impermeable to the organic electrolyte and resistant to the organic electrolyte, such as polypropylene or polyethylene, can be used.

[Metal foil laminated film]
As the metal foil laminated film 20 of the anode composite 2 of the present embodiment, for example, as shown in FIG. 5, three layers of a first resin layer 21, a metal foil layer 22, and a second resin layer 23 are arranged in this order. Can be used. One layer or a plurality of resin films such as a nylon film may be laminated between the layers to form a structure of four or more layers.

  For the first resin layer 21, for example, a polyolefin-based resin such as a polypropylene resin or a polyethylene resin can be used. These resins have a low melting point, are easily heat-processed, are suitable for heat sealing (heat welding), and facilitate the production of a negative electrode composite.

  The metal foil layer 22 is for improving gas barrier properties and strength. For example, a metal foil such as an aluminum foil, a SUS foil, and a copper foil can be used.

  For the second resin layer 23, for example, a polyester resin such as a polyethylene terephthalate resin or a nylon resin can be used. These resin materials are excellent in heat resistance and strength. Therefore, the strength and the like of the negative electrode composite can be improved.

[Electrolyte in negative electrode composite]
An electrolytic solution is sealed in a space between the isolation layer 40 and the first and second metal foil laminated films 20a and 20b. As the electrolytic solution, various electrolytic solutions such as an aqueous electrolytic solution and a non-aqueous electrolytic solution described with the electrolyte 3 sandwiched between the positive electrode 1 and the negative electrode composite 2 can be used. The electrolyte to be sealed in the negative electrode composite and the electrolyte sandwiched between the positive electrode and the negative electrode composite may be the same type of electrolyte or different types of electrolytes.

  Hereinafter, the present invention will be described in more detail with reference to examples of the present invention. However, the present invention is not limited to the following examples.

[1. Production of negative electrode composite]
First, an exterior material obtained by punching a central portion of a metal foil laminated film of PP resin / Al foil / PET resin into a 2 × 2 cm square, an acid-modified polypropylene film punched product (outer peripheral portion 3 × 3 cm, inner peripheral 2 × 2 cm), A 2.5 × 2.5 cm square solid electrolyte (LATP) and an acid-modified polypropylene film punched product (outer perimeter 3 × 3 cm, inner perimeter 2 × 2 cm) are stacked in this order, and four sides of the solid electrolyte are heat-welded with a heat sealer. To form an upper exterior body.

  Transfer to a glove box under an argon atmosphere, a negative electrode current collector with an acid-modified polypropylene film bonded to the back surface, and a copper foil with integrated terminals (copper foil thickness: 10 μm, current collector size: 2 × 7 cm) A metal Li foil (size 1.45 × 1.4 cm, thickness 0.2 mm) is bonded to the surface of a 2 × 2 cm portion of the above, and covered with a PP resin separator (protective layer) for a lithium ion battery, The four sides of the end of the negative electrode current collector and the part where the polypropylene was bonded were heat-welded and joined to form a negative electrode. An upper package, an integrated negative electrode, and a metal foil laminate film (with no opening) of the lower package are stacked on top of each other so that the solid electrolyte portion and the negative electrode face each other. Heat welding was performed with a sealer.

  2 ml of a non-aqueous electrolyte (4 M (mol / l) LiFSI / EGDME) was injected into the negative electrode composite body from the unjoined end. After discharging the gas in the outer package, finally, the other end of the one side (the portion where the tab of the negative electrode current collector was present) was joined and sealed with a heat sealer to produce a single-sided negative electrode composite. The negative electrode current collector and the upper and lower outer packages are heat-welded via a heat-welding sheet such as an acid-modified PP resin. LATP (manufactured by OHARA) was used as the solid electrolyte. As a separator (protective layer) for a lithium ion battery, a polypropylene resin having a thickness of 20 μm, vacancies of 60 to 70 nm, porosity of 42%, and air permeability of 250 sec / 100 cc was used.

  In the single-sided negative electrode composite, a metal Li foil is bonded instead of the acid-modified polypropylene film on the back surface of the copper foil, covered with a PP resin separator, and further, an upper package is used instead of the lower package. By stacking the bodies, a double-sided negative electrode composite was produced.

[2. Preparation of positive electrode]
A positive electrode was produced according to the following procedure.
(1) and 0.8 g MnO ₂ (specific surface area: 300 meters ² / g) having a catalytic activity as a cathode catalyst, a ketjen black (specific surface area 800m ² /g)0.1g as a conductive additive, a binder (binder 0.1 g of polytetrafluoroethylene (PTFE) was measured and transferred to an agate mortar, and 5 ml of ethanol was added as a dispersant and kneaded to obtain a positive electrode material.
(2) An upper mold having a plurality of rectangular convex cross-sections formed by a Ti mesh crimping section in which a 2.5 × 2.5 cm crimping section and a 1 × 5.5 cm tab section (terminal section) are integrated. (Protrusion height: about 2 mm, convex part width: about 2 mm, convex part pitch: about 4 mm, convex part R: 0.1 mm) and a lower mold (recess depth) having a plurality of rectangular concave sectional structures corresponding thereto. : About 2 mm, recess width: about 2 mm, recess pitch: about 4 mm, recess R: 0.1 mm) and pressed at a press pressure of 10 to 20 kN. Thereafter, the positive electrode material of (1) is divided into two equal parts, arranged on both sides of a crimped portion of a formed Ti mesh (wire diameter: 0.1 mm, 100 mesh), put into a mold again, and pressed with a press pressure of 20 kN. It crimped by doing. Thereafter, the positive electrode material protruding from the pressure-bonded portion of the Ti mesh was removed, and was naturally dried in air for 24 hours to produce a positive electrode.

[3. Preparation of electrolyte]
A mixture of LiOH and LiCl was used as an aqueous electrolyte solution, and the pH was adjusted to 10 or less. 1.5 ml of the above mixed solution was dropped onto a 3 × 3 cm polyacrylamide sheet to obtain an electrolyte.

[4. Production of metal-air battery]
A metal-air battery was produced by laminating the single-sided negative electrode composite, the electrolyte and the positive electrode produced in the above-described manner in this order. Further, an electrolyte, a double-sided negative electrode composite, an electrolyte, a positive electrode, an electrolyte, a double-sided negative electrode composite, an electrolyte, a positive electrode, an electrolyte, a single-sided negative electrode composite, By stacking in this order, a metal-air battery in which a plurality of cells were stacked was also manufactured.

1, 1A, 1B Positive electrode 2, 2A, 2B, 2C, 2X Negative electrode composite 2a Single-sided negative electrode composite 2b Double-sided negative electrode composite 3, 3A, 3B, 3C, 3D Electrolyte 20a First metal foil laminated film 20b Second metal foil laminated film 21 First resin layer 22 Metal foil layer 23 Second resin layer 30 Negative electrode 31 Negative current collector 31a Current collector 31b Terminal 32 Negative layer 33 Protective layer 34 Film 40 Isolation layer 50 Opening 100A Metal-air battery 100B Metal-air battery

Claims (8)

A first positive electrode;
A first electrolyte;
A negative electrode, a protective layer, and a first negative electrode composite including an isolation layer are stacked in this order;
A metal-air battery, wherein the first positive electrode has a cross-sectional structure including a plurality of concave portions, a plurality of convex portions, or a combination of a plurality of concave portions and a plurality of convex portions.   The metal-air battery according to claim 1, wherein a second electrolyte is laminated on a surface of the first positive electrode opposite to a surface on which the first electrolyte is laminated.   3. The metal-air battery according to claim 2, wherein a second negative electrode composite is laminated on a surface of the second electrolyte opposite to a surface on which the first positive electrode is laminated. A third electrolyte is laminated on a surface of the second anode composite opposite to a surface on which the second electrolyte is laminated,
A second positive electrode is laminated on a surface of the third electrolyte opposite to a surface on which the second negative electrode composite is laminated,
The metal-air battery according to claim 3, wherein the second positive electrode has a cross-sectional structure including a plurality of concave portions, a plurality of convex portions, or a combination of a plurality of concave portions and a plurality of convex portions.   The method according to claim 1, wherein the plurality of recesses, the plurality of protrusions, or the combination of the plurality of recesses and the plurality of protrusions has one shape selected from a rectangle, a triangle, and a curve. The metal-air battery according to claim 1.   The plurality of concave portions, the plurality of convex portions, or a combination of the plurality of concave portions and the plurality of convex portions are arranged in a lattice pattern on a plane of the positive electrode, according to any one of claims 1 to 5, wherein The metal-air battery as described.   The metal air according to any one of claims 1 to 6, wherein the protective layer covers the negative electrode, and the isolation layer is located between the protective layer and the first electrolyte. battery.   The metal-air battery according to any one of claims 1 to 7, wherein the first positive electrode includes a positive electrode current collector and a positive electrode material, and the positive electrode current collector is a metal mesh.