Sheet-type air batteries and patches

Abstract

Provided are a sheet-shaped air battery with excellent storage characteristics and a patch equipped with the sheet-shaped air battery. [Solution] The sheet-type air battery of the present invention comprises a positive electrode with a catalyst layer, a negative electrode, a separator, and an electrolyte solution housed in a sheet-type outer casing, the positive electrode having a porous carbon sheet current collector and a catalyst layer held by the current collector, the negative electrode having an active material and a metal foil sheet as a lead part, and the electrolyte solution being an aqueous solution containing an electrolyte salt and having a pH of 3 or more and less than 12, and containing 3 to 30 mass % of a water-soluble high-boiling point solvent with a boiling point of 150°C or more in the total solvent.

Description

[Technical Field]

[0001] The present invention relates to a sheet-type air battery having excellent storage characteristics and a patch including the sheet-type air battery. [Background technology]

[0002] Air batteries, which have a positive electrode made of an air electrode using manganese dioxide or carbon as a catalyst and a negative electrode whose active material is metal particles such as zinc particles or zinc alloy particles, have been used for many years as power sources for devices such as hearing aids.

[0003] This type of battery is generally button-shaped and uses a metal can for the exterior. Commercially available batteries have one to several air holes, each with a diameter of about 0.2 to 0.5 mm, formed on the bottom surface of the positive electrode side to allow air (oxygen) to enter the inside.

[0004] In addition, sheet-shaped batteries have been proposed that use resin film exteriors, such as laminated films made of aluminum and thermoplastic resin, and it has been disclosed that this allows for freedom in the shape of the battery and makes it possible to construct air batteries with excellent discharge characteristics (Patent Document 1).

[0005] In such air batteries, gas can pass through the air holes. Therefore, it is known that the composition of the electrolyte changes depending on the humidity of the surrounding environment; for example, when the humidity of the surrounding environment decreases, water evaporates from the electrolyte in the battery and dissipates outside the battery system through the air holes. On the other hand, when the humidity of the surrounding environment increases, water vapor is taken into the battery, increasing the water content of the electrolyte.

[0006] Therefore, if the battery is left unused for a long period of time, the composition of the electrolyte may change, which may result in a deterioration in the battery characteristics or problems such as electrolyte leakage.

[0007] To solve these problems, it has been proposed to add a polyhydric alcohol and / or a derivative thereof to the electrolyte solution to reduce the vapor pressure of the electrolyte solution, or to use a crosslinked material such as a resin in which a polymethacrylic acid-ethylene glycol copolymer is crosslinked with a crosslinking agent, crosslinked carboxymethyl cellulose, or crosslinked polyacrylic acid as a gelling agent for the negative electrode to gel the negative electrode (Patent Documents 2 to 5). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-288571 [Patent Document 2] Japanese Unexamined Patent Publication No. 61-13580 [Patent Document 3] Japanese Patent Application Laid-Open No. 2002-343450 [Patent Document 4] Special Publication No. 7-32030 [Patent Document 5] Special Publication No. 2009-530786 Summary of the Invention [Problem to be solved by the invention]

[0009] However, the storage characteristics of air batteries could not be significantly improved by using only the above techniques.

[0010] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a sheet-type air battery having excellent storage characteristics, and a patch including the sheet-type air battery. [Means for solving the problem]

[0011] The sheet-like air battery of the present invention comprises a positive electrode having a catalyst layer, a negative electrode, a separator, and an electrolyte solution housed in a sheet-like outer casing, the positive electrode having a porous carbon sheet current collector and a catalyst layer held by the current collector, the negative electrode having a metal foil sheet as an active material and a lead portion, and the electrolyte solution being an aqueous solution containing an electrolyte salt and having a pH of 3 or more and less than 12, and containing 3 to 30 mass % of a water-soluble high-boiling point solvent with a boiling point of 150°C or more in the total solvent.

[0012] The patch of the present invention can be attached to the body and is equipped with the sheet-shaped air battery of the present invention as a power source. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a sheet-type air battery having excellent storage characteristics and a patch including the sheet-type air battery. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a plan view schematically illustrating an example of a sheet-shaped air battery of the present invention. [Figure 2] FIG. 2 is a cross-sectional view taken along line II in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] In a first embodiment of the sheet-shaped air battery of the present invention, an electrolyte solution is used which is an aqueous solution having a pH of 3 or more and less than 12, and which contains 3 to 30 mass % of a water-soluble high-boiling point solvent having a boiling point of 150°C or more in the total solvent.

[0016] The high-boiling-point solvent can be considered substantially non-volatile, and it is believed that it can reduce the vapor pressure of water depending on the content, thereby suppressing the evaporation of water from the electrolyte. As a result, in the sheet-type air battery of the first embodiment, it is possible to suppress the liquid drying-up that can occur when water evaporates from the electrolyte and dissipates outside the battery through the air holes provided in the sheet-type outer casing, and therefore it is possible to maintain good discharge characteristics for a long period of time. Therefore, the sheet-type air battery of the first embodiment has excellent storage characteristics.

[0017] The upper limit of the boiling point of the water-soluble high-boiling solvent is usually 320°C.

[0018] From the viewpoint of maintaining the discharge characteristics of the sheet-type air battery better, it is desirable that the water-soluble high-boiling-point solvent has a high surface tension and a high relative dielectric constant. In the sheet-type air battery, the positive electrode (catalyst layer) needs to come into contact with air during discharge, and the surface tension of the water-soluble high-boiling-point solvent in the electrolyte is If the surface of the positive electrode catalyst layer is too low, it becomes easily wetted by the electrolyte, which may inhibit the reaction of the catalyst layer and reduce the discharge characteristics. However, by using a water-soluble high-boiling-point solvent with high surface tension, such problems can be avoided.

[0019] Furthermore, since organic solvents usually have a lower dielectric constant than water, when an electrolyte solution is prepared by mixing an organic solvent with water, the ionic conductivity decreases compared to when water alone is used, which may impair the discharge characteristics of the battery. However, the use of a water-soluble high-boiling-point solvent with a high dielectric constant can prevent such problems from occurring.

[0020] Specifically, the surface tension of the water-soluble high-boiling solvent is preferably 30 mN / m or more. The upper limit of the surface tension of the water-soluble high-boiling solvent is usually 70 mN / m. The surface tension of the water-soluble high-boiling solvent referred to in this specification is a value measured by the Wilhelmy method using a commercially available device (for example, "CBVP-Z" manufactured by Kyowa Interface Science Co., Ltd.).

[0021] Furthermore, the relative dielectric constant of the water-soluble high-boiling solvent is preferably 30 or more. The upper limit of the relative dielectric constant of the water-soluble high-boiling solvent is usually 65. The relative dielectric constant of the water-soluble high-boiling solvent referred to in this specification is a value determined from the dielectric constant measured using a Hewlett-Packard "Presion LCR Meter HP4284" or the like.

[0022] Specific examples of water-soluble high-boiling point solvents suitable for the electrolyte include polyhydric alcohols such as ethylene glycol (boiling point 197°C, surface tension 48 mN / m, dielectric constant 39), propylene glycol (boiling point 188°C, surface tension 36 mN / m, dielectric constant 32), and glycerin (boiling point 290°C, surface tension 63 mN / m, dielectric constant 43); and polyalkylene glycols (preferably those with a molecular weight of 600 or less) such as polyethylene glycol (PEG; for example, boiling point 230°C, surface tension 43 mN / m, dielectric constant 35). The electrolyte may contain only one of these water-soluble high-boiling point solvents, or two or more of them may be used in combination, but it is more preferable to use glycerin.

[0023] When a water-soluble high-boiling solvent is used, the content of the water-soluble high-boiling solvent in the total solvent of the electrolyte solution is 1% by mass or more, preferably 3% by mass or more, from the viewpoint of ensuring the effects of its use. However, if the amount of the water-soluble high-boiling solvent in the electrolyte solution is too large, the ionic conductivity of the electrolyte solution may become too low, which may result in a deterioration in battery characteristics. Therefore, the content of the water-soluble high-boiling solvent in the total solvent of the electrolyte solution is 30% by mass or less, preferably 20% by mass or less.

[0024] In a second embodiment of the sheet-shaped air battery of the present invention, an electrolyte is used which is prepared by blending an aqueous solution (electrolyte) containing an electrolyte salt and having a pH of 3 or more and less than 12, with a thickener.

[0025] The thickener added to the electrolyte solution increases the viscosity of the electrolyte solution, preferably forming a gel electrolyte, and also functions as a moisturizer. This prevents the sheet-shaped air battery of the second embodiment from drying up, which can occur when water evaporates from the electrolyte and dissipates outside the battery through the air holes in the sheet-shaped exterior. This allows the battery to maintain good discharge characteristics for a long period of time. Therefore, the sheet-shaped air battery of the second embodiment has excellent storage characteristics.

[0026] Examples of thickeners for forming electrolytes include cellulose derivatives such as carboxymethyl cellulose (CMC) and carboxyethyl cellulose (CEC); polyalkylene glycols such as polyethylene glycol (PEG) (preferably with a molecular weight of 1,000 or more, more preferably 10,000 or more); and various synthetic or natural polymers such as polyvinylpyrrolidone, polyvinyl acetate, starch, guar gum, xanthan gum, sodium alginate, hyaluronic acid, gelatin, and polyacrylic acid. To form an electrolyte, only one of the above water-soluble polymers may be used, or two or more may be used in combination. Polyalkylene glycols such as PEG are generally commercially available with their molecular weights (average molecular weights) clearly stated. The molecular weight of polyalkylene glycols referred to herein refers to the nominal value published by the manufacturer.

[0027] Among the above-mentioned water-soluble polymers, polysaccharides such as CMC and xanthan gum, and polyalkylene glycols with high molecular weights (molecular weights of 1000 or more) are more preferred because they have a high thickening effect on the electrolyte solution and can more easily prepare an electrolyte with good properties.

[0028] CMC is an anionic polymer and is easily affected by the coexistence of metal ions and salts, which may reduce its electrolyte thickening effect. However, when the degree of etherification of CMC is high, it is less affected by metal ions and salts, and the electrolyte thickening effect can be better exhibited. Specifically, the degree of etherification of CMC is preferably 0.9 or more, and more preferably 1.0 or more. The degree of etherification of CMC here refers to a value representing the number of carboxymethyl groups ether-bonded per anhydroglucose unit. Furthermore, the degree of etherification of CMC is preferably 1.6 or less.

[0029] Furthermore, when using a thickener such as CMC, CEC, xanthan gum, or sodium alginate that has a functional group consisting of a carboxyl group or its salt (-COOH, -COONa, etc.) in the molecule, it is preferable to add a polyvalent metal salt that acts as a gelation accelerator to the electrolyte. In this case, the gelation accelerator acts on the thickener, thereby gelling the electrolyte more effectively, making it even easier to form a gel electrolyte with good properties.

[0030] The polyvalent metal salt usable as the gelation accelerator varies depending on the type of thickener used, but is preferably a salt of a divalent or trivalent metal ion. Examples include alkaline earth metal salts such as magnesium salts (e.g., magnesium sulfate) and calcium salts (e.g., calcium sulfate); aluminum salts such as aluminum nitrate and aluminum sulfate; iron salts such as iron(II) chloride, iron(III) chloride, and iron(III) sulfate; and chromium salts such as chromium nitrate. Among these, aluminum salts and iron salts are more preferred. In the sheet-shaped air battery of the second embodiment, an aqueous solution with a pH of 3 or higher but lower than 12 is used to form the electrolyte, thereby reducing the environmental impact of the battery (described in detail below). However, using aluminum salts or iron salts as the gelation accelerator can prevent the increase in the environmental impact of the gelation accelerator.

[0031] Furthermore, the amount of thickener in the electrolyte is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, from the viewpoint of sufficiently increasing the viscosity of the electrolyte and ensuring good ionic conductivity, and is preferably 5% by mass or less, more preferably 3% by mass or less.

[0032] Furthermore, when a polyvalent metal salt serving as a gelation accelerator is blended in the electrolyte, the blending amount of the polyvalent metal salt is, from the viewpoint of better exerting its effect, preferably 1 or more, and more preferably 2 or more, when the mass ratio of the thickener is taken as 100. Furthermore, even if the blending amount of the polyvalent metal salt is increased, the effect saturates, so the blending amount of the polyvalent metal salt in the electrolyte is preferably 30 or less, and more preferably 20 or less, when the mass ratio of the thickener is taken as 100.

[0033] When the electrolyte salt also serves as a gelation accelerator, the amount of the gelation accelerator to be added may be set to the preferred concentration range of the electrolyte salt described above.

[0034] The electrolyte solution for the sheet-type air battery of the first embodiment is an aqueous solution containing an electrolyte salt together with a water-soluble high-boiling point solvent, and having a pH of 3 or more and less than 12. In the sheet-type air battery of the second embodiment, an aqueous solution containing an electrolyte salt and having a pH of 3 or more and less than 12 is used to form the electrolyte.

[0035] Examples of electrolyte salts to be dissolved in the aqueous solution include chlorides such as sodium chloride, potassium chloride, magnesium chloride, calcium chloride, ammonium chloride, and zinc chloride; hydroxides of alkali metals and alkaline earth metals (sodium hydroxide, potassium hydroxide, magnesium hydroxide, etc.), acetates (sodium acetate, potassium acetate, magnesium acetate, etc.), nitrates (sodium nitrate, potassium nitrate, magnesium nitrate, etc.), sulfates (sodium sulfate, potassium sulfate, magnesium sulfate, etc.), phosphates (sodium phosphate, potassium phosphate, magnesium phosphate, etc.), borates (sodium borate, potassium borate, magnesium borate, etc.), citrates (sodium citrate, potassium citrate, magnesium citrate, etc.), glutamate (sodium glutamate, potassium glutamate, magnesium glutamate, etc.); alkali metal bicarbonates (sodium bicarbonate, potassium bicarbonate, etc.); alkali metal percarbonates (sodium percarbonate, potassium percarbonate, etc.); halogen-containing compounds such as fluorides; and polycarboxylic acids. The aqueous solution may contain one or more of these electrolyte salts.

[0036] The electrolyte salt is preferably a salt of a strong acid selected from hydrochloric acid, sulfuric acid, and nitric acid with a weak base such as ammonia or a hydroxide of a metal element, such as aluminum hydroxide or magnesium hydroxide, and more preferably an ammonium salt or a salt of a specific metal element. - , SO4 2- , HSO4 - and NO3 -and at least one ion selected from Al ions, Mg ions, Fe ions, and ammonium ions. Examples of suitable ions include ammonium salts such as ammonium sulfate, ammonium hydrogen sulfate [(NH4)HSO4], ammonium chloride, and ammonium nitrate; aluminum salts such as aluminum sulfate, aluminum chloride, and aluminum nitrate; magnesium salts such as magnesium sulfate, magnesium chloride, magnesium chloride hydroxide [MgCl(OH)], and magnesium nitrate; and iron salts such as iron(II) sulfate, ammonium iron(II) sulfate [(NH4)2Fe(SO4)2], iron(III), iron(II) chloride, and iron(II) nitrate.

[0037] Aqueous solutions containing the above-mentioned salts of strong acids and weak bases have a relatively weaker effect of corroding metals and alloys, which are negative electrode active materials, than aqueous solutions (electrolytes) containing salts of strong acids and strong bases such as sodium chloride. Furthermore, among the salts of strong acids, aqueous solutions containing salts of metal elements selected from Al, Mg, and Fe, or ammonium salts, have a relatively higher electrical conductivity than, for example, aqueous zinc chloride solutions. Therefore, as salts of strong acids and weak bases, Cl - , SO4 2- , HSO4 - and NO3 - When an aqueous solution containing a salt of at least one ion selected from the group consisting of Al ions, Mg ions, Fe ions, and ammonium ions is used, the discharge characteristics of the sheet-shaped air battery can be further improved.

[0038] However, Cl - ions and Fe 3+ Regarding salts with ions [iron(III) chloride], it is preferable to use a salt other than iron(III) chloride because it has a stronger corrosive effect on the metal material that is the negative electrode active material than salts with other ion combinations, and it is more preferable to use an ammonium salt because it is less likely to corrode the metal material that is the negative electrode active material.

[0039] In the electrolyte used in the sheet-shaped air battery of the second embodiment, depending on the combination of electrolyte salt and thickener, the electrolyte salt itself may act as a gelation promoter, making it impossible to form a homogeneous gel electrolyte or a gel electrolyte with sufficient ionic conductivity. In such cases, the above problems can be prevented by using only a monovalent metal ion salt as the electrolyte salt, using a polyvalent metal ion salt in combination with a monovalent metal ion salt, or separately preparing an aqueous solution containing the electrolyte salt and an aqueous solution containing the thickener and then mixing them to prepare the electrolyte. It is also preferable to use an ammonium salt as the electrolyte salt.

[0040] Furthermore, among the salts of the strong acid and the weak base, perchlorates pose a risk of combustion or explosion when heated or impacted. Therefore, from the viewpoint of environmental load and safety during disposal, it is preferable that the aqueous solution does not contain perchlorate ions, or if it does contain perchlorate ions, the amount thereof is small (preferably less than 100 ppm, more preferably less than 10 ppm).

[0041] Furthermore, among the salts of strong acids and weak bases, many heavy metal salts (excluding iron salts), such as zinc chloride and copper sulfate, are harmful. Therefore, from the viewpoint of environmental load and safety during disposal, it is preferable that the aqueous solution does not contain such salts, or, if it does contain such salts, the amount of heavy metal ions excluding iron ions is small (preferably less than 100 ppm, more preferably less than 10 ppm).

[0042] The pH of the aqueous solution is 3 or more, preferably 5 or more, and less than 12, preferably 10 or less, and more preferably less than 7. By using an aqueous solution with such a pH, safety when disposing of the sheet-shaped air battery can be improved and the burden on the environment after disposal can be reduced, compared to, for example, when using an alkaline aqueous solution with a high pH that is a strong alkali.

[0043] The concentration of the electrolyte salt in the aqueous solution may be, for example, a concentration that allows the conductivity of the electrolytic solution to be adjusted to about 80 to 700 mS / cm, and is usually 5 to 50 mass %.

[0044] The aqueous solution preferably contains an indium compound dissolved therein, which can effectively suppress the generation of hydrogen gas within the battery.

[0045] Examples of the indium compound to be dissolved in the aqueous solution include indium hydroxide, indium oxide, indium sulfate, indium sulfide, indium nitrate, indium bromide, and indium chloride.

[0046] The concentration of the indium compound in the aqueous solution is preferably 0.005% or more, more preferably 0.01% or more, and particularly preferably 0.05% or more, by mass, and is preferably 1% or less, more preferably 0.5% or less, and particularly preferably 0.1% or less.

[0047] In addition to the above-described components, various known additives may be added to the aqueous solution as needed, as long as the effects of the present invention are not impaired. For example, zinc oxide may be added to prevent corrosion (oxidation) of the metal material used in the negative electrode. Zinc oxide may also be added to the negative electrode.

[0048] In the sheet-shaped air battery of the first embodiment, the electrolyte may be liquid, or may be made into a so-called gel by using a thickener, etc. When a gel electrolyte (gel electrolyte) is used, the corrosion suppression effect of the negative electrode active material is further improved.

[0049] For example, a foil of a metal or alloy serving as the negative electrode active material can be used as is for the negative electrode, but in this case, corrosion by the electrolyte can cause the foil to break, impairing the conductivity of the negative electrode and preventing the negative electrode from fully utilizing its capacity. Even when such a negative electrode is used, the use of an electrolyte having the above-mentioned electrolyte salt concentration can prevent the foil from breaking, but when a gel electrolyte is used, the effect of preventing this is further improved, so that the decrease in battery capacity can be more effectively prevented.

[0050] Examples of thickeners that can be used in the electrolyte solution include polyacrylic acids (such as polyacrylic acid, sodium polyacrylate, and ammonium polyacrylate) and celluloses (such as CMC, methyl cellulose, hydroxypropyl cellulose, and alkali salts thereof). Furthermore, as disclosed in Japanese Patent Application Laid-Open No. 2001-307746, it is also preferable to use crosslinked polyacrylic acid or its salt-type water-absorbent polymer (such as sodium polyacrylate and ammonium polyacrylate) in combination with other thickeners. Examples of thickeners that can be used in combination with crosslinked polyacrylic acid or its salt-type water-absorbent polymer include the aforementioned celluloses and crosslinked branched polyacrylic acid or its salts (such as sodium salt and ammonium salt). In addition to these, various synthetic or natural polymers exemplified as thickeners that can be used in the electrolyte of the sheet-shaped air battery of the second embodiment can also be used as thickeners. These thickeners may be used alone or in combination.

[0051] Among these thickeners, CMC having a degree of etherification of 0.9 to 1.6 is preferred because it has a strong effect of thickening the electrolyte and can easily prepare a gelled electrolyte solution (gelled electrolyte) with better properties, as described above with respect to the thickener for the electrolyte in the sheet-shaped air battery of the second embodiment.

[0052] In the sheet-shaped air battery of the second embodiment, it is preferable that the electrolyte contains a water-soluble high-boiling solvent having a boiling point of 150°C or higher, which can more effectively suppress the deterioration of battery characteristics due to evaporation of water from the electrolyte (depletion of liquid), and further improve the storage characteristics of the battery. The upper limit of the boiling point of the water-soluble high-boiling solvent is usually 320°C.

[0053] Furthermore, for the same reasons as in the case of the sheet-type air battery of the first embodiment, it is desirable that the water-soluble high-boiling-point solvent used in the sheet-type air battery of the second embodiment has high surface tension and dielectric constant. The suitable surface tension and dielectric constant values ​​of the water-soluble high-boiling-point solvent are also the same as in the case of the sheet-type air battery of the first embodiment. Furthermore, specific examples of water-soluble high-boiling-point solvents that can be used in the sheet-type air battery of the second embodiment are also the same as in the case of the sheet-type air battery of the first embodiment.

[0054] When a water-soluble high-boiling point solvent is used in the electrolyte of the sheet-type air battery of the second embodiment, the content of the water-soluble high-boiling point solvent in all solvents of the electrolyte is preferably 1 mass% or more, more preferably 3 mass% or more, and preferably 30 mass% or less, more preferably 20 mass% or less, for the same reasons as the content of the water-soluble high-boiling point solvent in all solvents of the electrolyte solution of the first sheet-type air battery.

[0055] The following describes the common configuration between the sheet-type air battery of the first embodiment and the sheet-type air battery of the second embodiment.

[0056] The positive electrode (air electrode) of the sheet-type air battery has a catalyst layer, and for example, a structure in which a catalyst layer and a current collector are laminated can be used.

[0057] The catalyst layer may contain a catalyst, a binder, and the like.

[0058] Examples of the catalyst for the catalyst layer include silver, platinum group metals or alloys thereof, transition metals, platinum / metal oxides such as Pt / IrO2, La 1-x Ca x Examples include perovskite oxides such as CoO3, carbides such as WC, nitrides such as Mn4N, manganese oxides such as manganese dioxide, and carbon (graphite, carbon black (acetylene black, ketjen black, channel black, furnace black, lamp black, thermal black, etc.), charcoal, activated carbon, etc.), and one or more of these may be used.

[0059] The catalyst layer preferably contains 1% by mass or less of heavy metals, excluding components of the electrolyte solution. In the case of a positive electrode having a catalyst layer with such a low heavy metal content, the battery can be disposed of without any special treatment, resulting in a low environmental impact.

[0060] The content of heavy metals in the catalyst layer referred to in this specification can be measured by fluorescent X-ray analysis. For example, it can be measured using a Rigaku "ZSX100e" under the conditions of an excitation source of Rh 50 kV and an analysis area of ​​φ10 mm.

[0061] Therefore, it is recommended that the catalyst for the catalyst layer does not contain heavy metals, and it is more preferable to use the various carbons mentioned above.

[0062] In addition, from the viewpoint of further increasing the reactivity of the positive electrode, the specific surface area of ​​the carbon used as a catalyst is set to 200 m 2 / g or more is preferable, and 300m 2 / g or more is more preferable, and 500m 2 / g or more is more preferable. The specific surface area of ​​carbon referred to in this specification is a value determined by the BET method in accordance with JIS K 6217, and can be measured, for example, using a specific surface area measuring device ("Macsorb HM model e-1201" manufactured by Mountech Co., Ltd.) using the nitrogen adsorption method. The upper limit of the specific surface area of ​​carbon is usually 2000 m 2 / g.

[0063] The catalyst content in the catalyst layer is preferably 20 to 70 mass %.

[0064] Examples of binders for the catalyst layer include fluororesin binders such as PVDF, PTFE, vinylidene fluoride copolymers, and tetrafluoroethylene copolymers (e.g., vinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), vinylidene fluoride-chlorotrifluoroethylene copolymer (PVDF-CTFE), vinylidene fluoride-tetrafluoroethylene copolymer (PVDF-TFE), and vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer (PVDF-HFP-TFE)). Among these, tetrafluoroethylene polymers (PTFE) or copolymers are preferred, with PTFE being more preferred. The binder content in the catalyst layer is preferably 3 to 50% by mass.

[0065] The positive electrode can be produced, for example, by mixing the catalyst, binder, etc. with water, rolling the mixture with a roll, and then contacting the mixture with a current collector. Alternatively, the positive electrode can be produced by dispersing the catalyst and a binder, etc., used as needed, in water or an organic solvent to prepare a catalyst layer-forming composition (slurry, paste, etc.), applying the composition to the surface of the current collector, drying the composition, and then subjecting the resulting mixture to a pressing process such as calendering, as needed.

[0066] The current collector for the positive electrode can be, for example, a mesh, foil, expanded metal, or punched metal made of metal such as titanium, nickel, stainless steel, or copper; a porous carbon sheet such as a carbon mesh, carbon cloth, or carbon paper; etc. The thickness of the current collector for the positive electrode is preferably 10 μm or more and 300 μm or less.

[0067] The positive electrode current collector can also be a part of a resin film constituting a sheet-like outer package or a laminate of a resin film and a metal film. In this case, for example, a carbon paste can be applied to the surface of the resin film or the laminate that is intended to become the inner surface of the sheet-like outer package to form a current collector, or the metal layer of the laminate can be used as a current collector, and a positive electrode mixture layer and a catalyst layer can be formed on this surface in the same manner as above to form a positive electrode. The thickness of the carbon paste layer is preferably 30 to 300 μm.

[0068] The negative electrode of a sheet-shaped air battery can be made of a metal material such as a zinc-based material (a collectively referred to as zinc material and zinc alloy material), a magnesium-based material (a collectively referred to as magnesium material and magnesium alloy material), or an aluminum-based material (a collectively referred to as aluminum material and aluminum alloy material). In such negative electrodes, metals such as zinc, magnesium, and aluminum act as active materials.

[0069] Specific examples of negative electrodes containing metal materials include negative electrodes containing zinc-based particles (a collectively referred to as zinc particles and zinc alloy particles), magnesium-based particles (a collectively referred to as magnesium particles and magnesium alloy particles), and aluminum-based particles (a collectively referred to as aluminum particles and aluminum alloy particles).

[0070] Examples of alloy components of zinc alloy particles include indium (for example, a content of 0.005 to 0.05% by mass), bismuth (for example, a content of 0.005 to 0.05% by mass), and aluminum (for example, a content of 0.001 to 0.15% by mass).

[0071] Examples of alloy components of magnesium alloy particles include calcium (e.g., a content of 1 to 3% by mass), manganese (e.g., a content of 0.1 to 0.5% by mass), zinc (e.g., a content of 0.4 to 1% by mass), and aluminum (e.g., a content of 8 to 10% by mass).

[0072] Further, examples of alloy components of the aluminum alloy particles include zinc (e.g., a content of 0.5 to 10% by mass), tin (e.g., a content of 0.04 to 1.0% by mass), gallium (e.g., a content of 0.003 to 1.0% by mass), silicon (e.g., a content of 0.05% or less by mass), iron (e.g., a content of 0.1% or less by mass), magnesium (e.g., a content of 0.1 to 2.0% by mass), and manganese (e.g., a content of 0.01 to 0.5% by mass).

[0073] In the case of a negative electrode containing metal particles, the metal particles may be of one type alone or two or more types.

[0074] In consideration of reducing the environmental impact when batteries are disposed of, it is preferable that the metal material used for the negative electrode contains small amounts of mercury, cadmium, lead, and chromium, and more preferably the specific contents are, by mass, mercury: 0.1% or less, cadmium: 0.01% or less, lead: 0.1% or less, and chromium: 0.1% or less.

[0075] Regarding the particle size of the zinc-based particles, for example, the proportion of particles with a particle size of 75 μm or less among all particles is preferably 50 mass% or less, more preferably 30 mass% or less, and the proportion of particles with a particle size of 100 to 200 μm is 50 mass% or more, more preferably 90 mass% or more.

[0076] Furthermore, with regard to the particle size of the magnesium-based particles and aluminum-based particles, for example, the proportion of particles with a particle size of 30 μm or less among all particles is preferably 50 mass% or less, more preferably 30 mass% or less, and the proportion of particles with a particle size of 50 to 200 μm is 50 mass% or more, more preferably 90 mass% or more.

[0077] The particle size of metal particles referred to in this specification is the particle size at a cumulative frequency of 50% on a volume basis (D ) measured by dispersing the particles in a medium that does not dissolve the particles using a laser scattering particle size distribution analyzer (for example, "LA-920" manufactured by Horiba, Ltd.). 50 )

[0078] In the case of a negative electrode containing the above-mentioned metal particles, a thickener (such as sodium polyacrylate or CMC (especially CMC having the above-mentioned degree of etherification suitable as a thickener for electrolyte solutions)) or a binder may be added as needed, and an electrolyte solution may be added to the thickener to form a negative electrode agent (such as a gelled negative electrode). The amount of the thickener in the negative electrode is preferably 0.5 to 1.5 mass %, and the amount of the binder is preferably 0.5 to 3 mass %.

[0079] The electrolyte solution for the negative electrode containing metal particles can be the same aqueous solution as that injected into the sheet-type air battery of the first embodiment, or the same aqueous solution as that used to form the electrolyte of the sheet-type air battery of the second embodiment.

[0080] The content of metal particles in the negative electrode is, for example, preferably 60% by mass or more, more preferably 65% ​​by mass or more, and preferably 95% by mass or less, more preferably 90% by mass or less.

[0081] The negative electrode containing metal particles preferably contains an indium compound, which can more effectively prevent hydrogen gas generation due to a corrosion reaction between the metal particles and the electrolytic solution (electrolyte).

[0082] Examples of the indium compound include indium oxide and indium hydroxide.

[0083] The amount of the indium compound used in the negative electrode is preferably 0.003 to 1 in terms of mass ratio to 100 metal particles.

[0084] The negative electrode may be a metal sheet such as a zinc-based sheet (e.g., zinc foil or zinc alloy foil) having the same composition as the zinc-based particles, or a magnesium-based sheet (e.g., magnesium foil or magnesium alloy foil) having the same composition as the magnesium-based particles. In the case of such a negative electrode, the thickness is preferably 10 to 500 μm.

[0085] Furthermore, a current collector may be used as needed for a negative electrode containing a metal material. Examples of current collectors for a negative electrode containing a metal material include mesh, foil, expanded metal, and punched metal made of metals such as nickel, copper, and stainless steel; and carbon sheets and meshes. The thickness of the negative electrode current collector is preferably 10 μm or more and 300 μm or less.

[0086] As in the case of the positive electrode, the negative electrode current collector may be formed by applying a carbon paste to the inner surface of the sheet-like outer casing, or by using a metal layer that constitutes the sheet-like outer casing. The thickness of the carbon paste layer is preferably 50 to 200 μm.

[0087] Examples of separators for sheet-type air batteries include separators commonly used in various batteries, such as porous resin membranes (microporous membranes, nonwoven fabrics, etc.) and semipermeable membranes such as cellophane film. From the viewpoint of preventing short circuits and improving the load characteristics of sheet-type air batteries, it is preferable to use semipermeable membranes as separators.

[0088] Examples of resins that can be used to form separators made of porous resin films include polyolefins such as polyethylene (PE), polypropylene (PP), and ethylene-propylene copolymers.

[0089] In the case of a resin separator, the porosity is preferably 30 to 80%, and the thickness is preferably 10 to 100 μm.

[0090] Furthermore, when a semipermeable membrane such as a cellophane film is used as the separator, the separator may be constructed solely from the semipermeable membrane. However, since the semipermeable membrane has low strength, problems such as breakage during battery assembly are likely to occur. Therefore, it is also recommended to construct the separator from a laminate in which a graft film made of a specific polymer is laminated with the semipermeable membrane.

[0091] The graft polymer constituting the graft film has a form in which (meth)acrylic acid or its derivatives are graft polymerized onto a polyolefin (polyethylene, polypropylene, etc.) trunk polymer, for example. However, the graft polymer need only have the above-mentioned form, and it does not have to be produced by a method in which (meth)acrylic acid or its derivatives are graft polymerized onto a polyolefin.

[0092] The (meth)acrylic acid or its derivative constituting the graft polymer is represented by the following general formula (1): 1 is H or CH3, and R 2 means H or a hydrophilic substituent such as NH4, Na, K, Rb, or Cs.

[0093] [ka]

[0094] The polymers constituting the graft film and cellophane film themselves have the function of absorbing an electrolytic solution (electrolyte) and allowing ions to pass through.

[0095] The graft polymer constituting the graft film preferably has a graft ratio defined by the following formula (2) of 160% or more. Since there is a correlation between the graft ratio of the graft polymer and the electrical resistance of the graft film, by using a graft polymer having a graft ratio of the above value, the electrical resistance of the graft film can be increased to 20 to 120 mΩ·in 2 The electrical resistance of the graft film is a value obtained by the AC voltage drop method (1 kHz). The ambient temperature is set to 20 to 25°C, and the film is immersed in a 40% KOH (specific gravity: 1.400±0.005) aqueous solution at 25±1°C, and then removed after 5 to 15 hours, and the electrical resistance is measured.

[0096] Graft rate (%) = 100 × (AB) / B (2)

[0097] In the formula (2), A is the mass (g) of the graft polymer, and B is the mass (g) of the trunk polymer in the graft polymer. Regarding "B (mass of the trunk polymer in the graft polymer)" in the formula (2), for example, when the graft polymer is formed by graft polymerizing (meth)acrylic acid or a derivative thereof onto a polyolefin trunk polymer, the mass of the trunk polymer used in the graft polymerization can be measured in advance. The graft rate of the graft polymer may exceed 100% because the monomers used in the graft polymerization ((meth)acrylic acid or a derivative thereof) may polymerize with each other, resulting in long chain graft molecules. The upper limit of the graft rate of the graft polymer defined by the formula (2) is preferably 400%. The term "(meth)acrylic acid" collectively refers to acrylic acid and methacrylic acid.

[0098] In the case of a separator made of only a cellophane film, the thickness is, for example, preferably 15 μm or more, and preferably 40 μm or less, and more preferably 30 μm or less.

[0099] Furthermore, in the case of a separator composed of a laminate of a graft film and a cellophane film, the total thickness of the graft film and the cellophane film is, for example, preferably 30 μm or more, more preferably 40 μm or more, and preferably 70 μm or less, more preferably 60 μm or less.

[0100] Furthermore, in the case of a separator formed of a laminate of a graft film and a cellophane film, the thickness of the graft film is, for example, preferably 15 μm or more, more preferably 25 μm or more, and preferably 30 μm or less.

[0101] Examples of laminates of a graft film and a cellophane film for forming a separator include those commercially available from Yuasa Membrane Systems Co., Ltd. under the names "YG9132," "YG9122," and "YG2152."

[0102] Alternatively, the separator may be constructed by combining a cellophane film or a combination of a cellophane film and a graft film with a liquid-absorbing layer (electrolyte solution (electrolyte) retention layer) such as vinylon-rayon blend paper. The thickness of such a liquid-absorbing layer is preferably 20 to 500 μm.

[0103] The sheet-shaped air battery of the present invention has a sheet-shaped exterior body, which enables it to be used in applications where it is difficult to use a battery with an exterior can. In addition, it is easier to dispose of compared to a battery with an exterior can, so it is expected to take advantage of the advantage of a small environmental load.

[0104] An example of the sheet-type air battery of the present invention is shown schematically in Figures 1 and 2. Figure 1 is a plan view of the sheet-type air battery, and Figure 2 is a cross-sectional view taken along line II in Figure 1.

[0105] As shown in Fig. 2, the sheet-type air battery 1 contains a positive electrode 20, a separator 40, a negative electrode 30, an electrolytic solution, and an electrolyte (not shown) in a sheet-type exterior body 60. The positive electrode 20 is connected to a positive electrode external terminal 21 via a lead body within the battery 1, and although not shown, the negative electrode 30 is also connected to a negative electrode external terminal 31 via a lead body within the battery 1. The dotted line in Fig. 1 indicates the size of the catalyst layer for the positive electrode 20 contained in the sheet-type exterior body 60.

[0106] The sheet-like outer casing 60 has a plurality of air holes 61 on one side where the positive electrode 20 is arranged, for taking in air into the positive electrode, and a water-repellent film 50 is arranged on the sheet-like outer casing 60 side of the positive electrode 20 to prevent leakage of the electrolytic solution (electrolyte) through the air holes 61.

[0107] The positive electrode 20 has a catalyst layer, and as described above, for example, has a structure in which the catalyst layer is laminated with a current collector. However, in FIG. 2, in order to avoid cluttering the drawing, the layers of the positive electrode 20 are not shown separately.

[0108] The sheet-like outer packaging body can be made of, for example, a resin film, and examples of such resin films include nylon films (such as nylon 66 film), polyester films (such as polyethylene terephthalate (PET) film), etc. The thickness of the resin film is preferably 20 to 100 μm.

[0109] In general, sealing of the sheet-like outer packaging body is performed by heat-sealing the end of the upper resin film and the end of the lower resin film of the sheet-like outer packaging body. However, to facilitate this heat-sealing, a heat-sealing resin layer may be laminated on the resin film exemplified above and used for the sheet-like outer packaging body. Examples of heat-sealing resins that constitute the heat-sealing resin layer include modified polyolefin films (such as modified polyolefin ionomer films), polypropylene and copolymers thereof. The thickness of the heat-sealing resin layer is preferably 20 to 100 μm.

[0110] A metal layer may be laminated on the resin film. The metal layer may be made of an aluminum film (aluminum foil, including aluminum alloy foil), a stainless steel film (stainless steel foil), or the like. The thickness of the metal layer is preferably 10 to 150 μm.

[0111] The resin film constituting the sheet-like outer packaging body may be a film having a configuration in which the heat-sealable resin layer and the metal layer are laminated together.

[0112] The shape of the sheet-like outer casing may be polygonal in plan view (triangle, quadrangle, pentagon, hexagon, heptagon, octagon), or may be circular or elliptical in plan view. In the case of a sheet-like outer casing that is polygonal in plan view, the positive electrode external terminal and the negative electrode external terminal may be led out from the same side or from different sides.

[0113] As shown in Fig. 2, a sheet-type air battery typically has a water-repellent film disposed between the positive electrode and the exterior body, and the water-repellent film is a film that is water-repellent but air-permeable. Specific examples of such water-repellent films include films made of resins such as fluororesins such as PTFE; and polyolefins such as polypropylene and polyethylene. The thickness of the water-repellent film is preferably 50 to 250 µm.

[0114] An air diffusion membrane may be disposed between the exterior body and the water-repellent film to supply air taken into the exterior body to the positive electrode. The air diffusion membrane may be a nonwoven fabric made of a resin such as cellulose, polyvinyl alcohol, polypropylene, or nylon. The thickness of the air diffusion membrane is preferably 100 to 250 μm.

[0115] The thickness of the sheet-type air battery (the length of a in Fig. 2) is not particularly limited and can be changed appropriately depending on the intended use of the sheet-type air battery. One of the advantages of the sheet-type air battery is that it can be made thin, and from this perspective, the thickness is preferably, for example, 1 mm or less.

[0116] There is no particular lower limit to the thickness of the sheet-shaped air battery, but it is usually preferable to set it to 0.2 mm or more in order to ensure a certain capacity.

[0117] The sheet-type air battery of the present invention has excellent storage characteristics, and as described above, it has a small environmental impact. Even if the electrolyte leaks due to breakage and comes into contact with the body, it is less likely to cause problems than, for example, a strongly alkaline electrolyte with a high pH. Therefore, the sheet-type air battery of the present invention is suitable as a power source for medical and health-related devices, such as patches that can be worn on the body, particularly patches worn on the surface of the skin to measure body conditions such as body temperature, pulse rate, and sweat rate. It can also be used in the same applications as conventionally known air batteries. [Example]

[0118] The present invention will be described in detail below based on examples, but the present invention is not limited to these examples.

[0119] Example 1 <Positive electrode> DBP oil absorption 495cm 3 / 100g, specific surface area 1270m 2 A composition for forming a catalyst layer was prepared by mixing 30 parts by mass of carbon (Ketjenblack EC600JD (Lion Specialty Chemicals)) of 1000 kJ / g, 15 parts by mass of an acrylic dispersant, 60 parts by mass of SBR, and 500 parts by mass of water.

[0120] A porous carbon paper [thickness: 0.25 mm, porosity: 75%, air permeability (Gurley): 70 seconds / 100 ml] was used as a current collector, and the catalyst layer-forming composition was applied in an amount of 10 mg / cm after drying. 2The substrate surface was coated with the solution in stripes, and the resulting solution was dried to obtain a current collector having a catalytic layer and an uncoated area. This current collector was punched out to have a catalytic layer measuring 30 mm × 30 mm and a lead portion measuring 5 mm × 15 mm at one end where the catalytic layer was not formed, to produce a positive electrode (air electrode) with an overall thickness of 0.27 mm.

[0121] <Negative electrode> A zinc alloy foil (thickness: 0.05 mm) containing 0.05% In, 0.04% Bi, and 0.001% Al as additive elements was punched out into a shape having a 30 mm × 30 mm portion that would function as the active material and a 5 mm × 15 mm portion at one end that would serve as a lead portion, to prepare a negative electrode.

[0122] <Electrolyte> Glycerin was added to a 20% by mass aqueous solution of ammonium sulfate in an amount that would result in 10% by mass of the total amount with water to prepare an electrolyte solution (pH was 5.3 as measured at 25°C using a HORIBA, Ltd. "LAQUA twin compact pH meter." The same pH was determined by the same measurement method for the electrolyte solutions of the sheet-type batteries of all Examples and Comparative Examples described below.) The concentrations of perchlorate ions and heavy metal ions, excluding iron ions, in the electrolyte solution were each less than 100 ppm. The same was true for the electrolyte solutions of the sheet-type air batteries of Examples 2 to 5 and Comparative Examples 1 and 2 described below.

[0123] <separator> The separator used was made of two graft films (thickness per film: 15 μm) composed of a graft copolymer having a structure in which acrylic acid is graft copolymerized onto a polyethylene main chain, placed on both sides of a cellophane film (thickness: 20 μm) (total thickness: 50 μm).

[0124] <Water-repellent film> The water-repellent film was a PTFE sheet with a thickness of 200 μm.

[0125] <Battery assembly> Two sheets of 5 cm x 5 cm aluminum laminate film (thickness: 65 μm) having a PET film on the outer surface of the aluminum foil and a polypropylene film as a heat-sealable resin layer on the inner surface were used as the exterior body.

[0126] One of the exterior bodies, located on the positive electrode side, had nine 1-mm diameter air holes regularly spaced 9 mm long and 9 mm wide (the center-to-center distance between air holes was 10 mm), and the water-repellent film was heat-sealed to the inner surface using hot-melt resin. The other exterior body, located on the negative electrode side, had a modified polyolefin ionomer film attached parallel to the sides of the exterior body to the area where the positive and negative electrode leads were located, in order to improve the sealing of the heat-sealed joints between the leads and the exterior body.

[0127] The positive electrode, the separator, and the negative electrode were stacked in this order on the water-repellent film of the sheet-like outer casing facing downwards, and another outer casing was placed on top of it so that the modified polyolefin ionomer film was positioned on top of the leads of the positive electrode and the negative electrode. Next, the three sides of the two outer casings were heat-sealed to form a bag, and the electrolyte was poured into the opening, which was then heat-sealed to form a sheet-like air battery.

[0128] Example 2 An electrolyte solution was prepared in the same manner as in Example 1 except that propylene glycol was used instead of glycerin, and a sheet-shaped air battery was fabricated in the same manner as in Example 1 except that this electrolyte solution was used.

[0129] Example 3 An electrolyte solution was prepared in the same manner as in Example 1 except that ethylene glycol was used instead of glycerin, and a sheet-shaped air battery was fabricated in the same manner as in Example 1 except that this electrolyte solution was used.

[0130] Example 4 An electrolyte solution was prepared in the same manner as in Example 1, except that the amount of glycerin added was 5 mass % of the total amount including water, and a sheet-shaped air battery was fabricated in the same manner as in Example 1, except that this electrolyte solution was used.

[0131] Example 5 An electrolyte solution was prepared in the same manner as in Example 1, except that the amount of glycerin added was 20 mass % of the total amount including water, and a sheet-shaped air battery was fabricated in the same manner as in Example 1, except that this electrolyte solution was used.

[0132] Comparative Example 1 A sheet-shaped air battery was fabricated in the same manner as in Example 1, except that a 20 mass % aqueous solution of ammonium sulfate without added glycerin was used as the electrolyte solution.

[0133] Comparative Example 2 An electrolyte solution was prepared in the same manner as in Example 1, except that the amount of glycerin added was 50 mass % of the total amount including water, and a sheet-shaped air battery was fabricated in the same manner as in Example 1, except that this electrolyte solution was used.

[0134] The sheet-shaped air batteries of Examples 1 to 5 and Comparative Examples 1 and 2 were evaluated as follows.

[0135] [Evaluation of discharge characteristics] After assembling each sheet-shaped air battery, it was left in the atmosphere for 10 minutes, and then discharged to 0.5 V at a current equivalent to a 100-hour rate relative to the design capacity of the battery, and the discharge capacity (discharge capacity before storage) was measured. The measured values ​​of each battery were compared relative to the discharge capacity of the battery of Comparative Example 1, which was set to 100.

[0136] [Evaluation of discharge characteristic retention rate after storage test] After assembling each sheet-type air battery, it was stored in the atmosphere at 40°C for 10 days, and then the discharge capacity (discharge capacity after storage) was measured when it was discharged to 0.5V at a current equivalent to a 100-hour rate relative to the design capacity of the battery.

[0137] The ratio of the discharge capacity after storage to the discharge capacity before storage was determined as the capacity retention rate, and the storage characteristics were evaluated.

[0138] The composition of the electrolyte solution for each of the sheet-type air batteries in Examples 1 to 5 and Comparative Examples 1 and 2, and the evaluation results described above, are shown in Table 1. The content of the water-soluble high-boiling-point solvent in Table 1 is the content in the total solvent of the electrolyte solution.

[0139] [Table 1]

[0140] As shown in Table 1, the sheet-shaped air batteries of Examples 1 to 5, which used electrolyte solutions containing an appropriate amount of a water-soluble high-boiling-point solvent, had good discharge capacities and showed little capacity loss before and after storage, and also had excellent storage characteristics, compared to the battery of Comparative Example 1, which used an electrolyte solution that did not contain a water-soluble high-boiling-point solvent.In addition, the battery of Comparative Example 2, which used an electrolyte solution with an excessive amount of a water-soluble high-boiling-point solvent, had a smaller discharge capacity than the batteries of the Examples and Comparative Example 1.

[0141] Example 6 A 20% by mass ammonium sulfate aqueous solution ("LAQUA twin" manufactured by Horiba Ltd.) The pH was measured at 25°C using a compact pH meter and was found to be 5.3. The pH values ​​shown below were also measured using the same method.) was prepared, and CMC (etherification degree: 1.4) was added to it in an amount of 1.0 mass% and dissolved to form a highly viscous electrolyte. The concentrations of perchlorate ions and heavy metal ions excluding iron ions in the aqueous solution were each less than 100 ppm. The same applies to the aqueous solutions used to form the electrolytes of the sheet-shaped air batteries in Examples 7 to 11 and Comparative Example 3 described below.

[0142] A sheet-shaped air battery was fabricated in the same manner as in Example 1, except that the electrolyte prepared in Example 1 was replaced with the above electrolyte.

[0143] Example 7 An electrolyte was formed in the same manner as in Example 6, except that xanthan gum was used instead of CMC, and a sheet-shaped air battery was fabricated in the same manner as in Example 1, except that this electrolyte was used.

[0144] Example 8 An electrolyte was formed in the same manner as in Example 6, except that PEG (molecular weight: 2,000,000) was used instead of CMC, and a sheet-shaped air battery was fabricated in the same manner as in Example 1, except that this electrolyte was used.

[0145] Example 9 Solution (A) was prepared by dissolving CMC (etherification degree 1.4) in an ammonium sulfate aqueous solution (pH = 5.3). Separately, an aqueous solution (B) of aluminum sulfate, a gelation accelerator, was prepared. The amounts of ammonium sulfate, CMC, and aluminum sulfate were adjusted to 20 mass % ammonium sulfate, 1.0 mass % CMC, and 0.05 mass % aluminum sulfate, respectively, based on the total amounts of solution (A) and aqueous solution (B).

[0146] A sheet-shaped air battery was produced in the same manner as in Example 6, except that the solution (A) and the aqueous solution (B) were placed in a heat-sealed bag-shaped exterior body instead of the electrolyte prepared in Example 6. The solution (A) and the aqueous solution (B) were mixed and gelled inside the exterior body after the opening was heat-sealed.

[0147] Example 10 A sheet-shaped air battery was produced in the same manner as in Example 9, except that the aqueous solution (B) was replaced with an aqueous solution of iron (III) sulfate.

[0148] Example 11 A solution (A) (pH = 5.3) was prepared in the same manner as in Example 9, except that the solvent was changed to a mixed solvent of water and glycerin, and a sheet-shaped air battery was fabricated in the same manner as in Example 9, except that this solution (A) was used. The amount of glycerin was set to 5.0 mass % in the total amount of water and glycerin used in the solution (A) and the aqueous solution (B).

[0149] The sheet-shaped air batteries of Examples 6 to 11 were evaluated for discharge characteristics and storage characteristics (discharge characteristic retention rate after storage test) in the same manner as the battery of Example 1.

[0150] The structure of each sheet-shaped air battery in Examples 6 to 11 is shown in Table 2, and the evaluation results are shown in Table 3. Tables 2 and 3 also show the structure and evaluation results of the battery in Comparative Example 1. Note that the contents of the thickener and gelling accelerator in Table 2 are the contents in the entire electrolyte, and the content of the water-soluble high-boiling-point solvent is the content in the entire solvent in the electrolyte.

[0151] [Table 2]

[0152] [Table 3]

[0153] As shown in Tables 2 and 3, the sheet-shaped air batteries of Examples 6 to 11, which used electrolytes prepared by blending an aqueous solution containing an electrolyte salt and having a pH of 3 or more and less than 12 with a thickener, had larger discharge capacities and better discharge characteristics than the battery of Comparative Example 1, which used an electrolyte solution without a thickener. They also showed less capacity loss before and after storage and had excellent storage characteristics. [Explanation of symbols]

[0154] 1. Sheet-type air battery 20 Positive electrode (air electrode) 21 Positive external terminal 30 negative electrode 31 Negative external terminal 40 Separator 50 Water-repellent film 60 Sheet-shaped outer packaging 61 Air vent

Claims

1. A sheet-shaped air battery in which a positive electrode having a catalyst layer, a negative electrode, a separator, and an electrolyte are housed in a sheet-shaped outer casing, the positive electrode has a current collector made of a porous carbon sheet and a catalyst layer supported on the current collector, the negative electrode has an active material and a metal foil sheet as a lead portion, The electrolytic solution is an aqueous solution containing an electrolyte salt and having a pH of 3 or more and less than 12, and contains 3 to 30 mass % of a water-soluble high-boiling solvent having a boiling point of 150°C or more in the total solvent.

2. 2. The sheet-shaped air battery according to claim 1, wherein the metal foil is a zinc foil or a zinc alloy foil.

3. 3. The sheet-shaped air battery according to claim 2, wherein the metal foil is a zinc alloy foil containing bismuth.

4. 4. The sheet-shaped air battery according to claim 1, wherein the water-soluble high-boiling point solvent has a surface tension of 30 mN / m or more.

5. 5. The sheet-shaped air battery according to claim 1, wherein the water-soluble high-boiling-point solvent has a relative dielectric constant of 30 or more.

6. A patch that can be attached to the body, comprising the sheet-shaped air battery according to any one of claims 1 to 5 as a power source.

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