Aqueous electrolyte batteries and patches

Abstract

To provide an aqueous electrolyte battery which is excellent in load characteristics and reliability, and a patch including the battery.SOLUTION: There is provided an aqueous electrolyte battery in which a positive electrode, a negative electrode containing a metal material, a separator and an aqueous electrolyte are stored in an exterior body. The separator is a porous film which is made of a resin, and has thickness of 5 μm or more and 100 μm or less, air permeability of 10 sec / 100 mL or more and 3,000 sec / 100 mL or less, and a contact angle of water of 90° or less, and the negative electrode has an electrolyte zinc foil. The patch can be worn on a body, and includes the aqueous electrolyte battery as a power source.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an aqueous electrolyte battery having excellent load characteristics and reliability, and a patch equipped with the battery. [Background technology]

[0002] Batteries that use an aqueous electrolyte, such as air batteries and alkaline batteries, are generally button-shaped batteries that use a metal can as an exterior body, or cylindrical batteries that use a cylindrical exterior can.

[0003] On the other hand, a battery having such a negative electrode is also being made into a sheet-type battery using an exterior body made of a resin film (Patent Document 1, etc.).

[0004] Taking advantage of the shape and other characteristics of such batteries, they are being considered for use as power sources for various body sensors, such as temperature patches. In order to better meet such needs, Patent Document 1 uses an electrolyte with a low pH so that the impact on the environment can be minimized even when users discard the replaced batteries.

[0005] Note that the use of an electrolyte solution with a low pH as described above tends to reduce the discharge capacity of the battery, but the battery described in Patent Document 1 avoids this problem by using a separator made of a semipermeable membrane such as a resin microporous membrane or nonwoven fabric, or a cellophane film, and whose air permeability is limited to a specific value or more. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2018 / 056307 Summary of the Invention [Problem to be solved by the invention]

[0007] In recent years, applications of batteries containing aqueous electrolyte solutions that require discharge at a relatively large current value have been considered. Accordingly, there are cases where improvements in load characteristics are required. However, the technology described in Patent Document 1 still has room for improvement in this regard.

[0008] On the other hand, it is conceivable that the load characteristics of a battery can be improved by using a membrane with very low air permeability and excellent ion permeability, such as a resin nonwoven fabric, as a separator. However, batteries with such separators are prone to micro-short circuits, which can lead to problems such as a loss of reliability.

[0009] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an aqueous electrolyte battery having excellent load characteristics and reliability, and a patch including the battery. [Means for solving the problem]

[0010] The aqueous electrolyte battery of the present invention comprises a positive electrode, a negative electrode containing a metal material, a separator, and an aqueous electrolyte housed in an exterior body, the separator being a porous film having a thickness of 5 μm to 100 μm, an air permeability of 10 sec / 100 mL to 3000 sec / 100 mL, and a contact angle with water of 90° or less, and the negative electrode having electrolytic zinc foil.

[0011] The patch of the present invention is characterized in that it can be attached to the body and includes the aqueous electrolyte battery of the present invention as a power source. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide an aqueous electrolyte battery having excellent load characteristics and reliability, and a patch including the battery. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a plan view schematically illustrating an example of an aqueous electrolyte 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

[0014] The separator of the aqueous electrolyte battery of the present invention is made of a resin and is composed of a porous film having a thickness of 5 μm or more and 100 μm or less, an air permeability of 10 sec / 100 mL or more and 3000 sec / 100 mL or less, and a contact angle with water of 90° or less.

[0015] As mentioned above, when a semipermeable membrane such as a cellophane film is used, it is possible to prevent a decrease in the discharge capacity of a battery, even when an electrolyte solution with a pH of 3 or more and less than 12 is used. On the other hand, although a semipermeable membrane has ion permeability, it is a substantially non-porous membrane with very high air permeability, so the amount of ions that are responsible for the battery reaction that can pass through is limited, which tends to deteriorate the load characteristics of the battery (discharge characteristics under heavy load).

[0016] On the other hand, nonwoven fabrics made of resins such as polyolefins have an air permeability of less than 5 sec / 100 mL and very high ion permeability, and although batteries using these as separators can suppress the decline in load characteristics, they are prone to micro-short circuits and have poor reliability and storage properties. This is thought to be because separators made of nonwoven fabrics usually have large pores (voids), which allow the protrusions on the surface of the positive or negative electrode to pass through these pores and come into contact with the counter electrode.

[0017] Furthermore, when a microporous membrane made of a resin such as polyolefin, which is commonly used in nonaqueous secondary batteries, is used as a separator, the occurrence of the micro-short circuit can be suppressed more effectively than when a nonwoven fabric is used as a separator, but the load characteristics of the battery tend to deteriorate, as in the case of using a semipermeable membrane as a separator. According to the studies of the present inventors, it was found that the poor load characteristics are caused by the fact that the microporous membrane made of the resin is difficult to wet with an aqueous electrolyte solution and has poor ion permeability.

[0018] Therefore, in the present invention, a porous resin membrane having a specific thickness, a specific air permeability, and a contact angle with water of 90° or less is used as the separator. The porous membrane has a high affinity with water, which is the solvent constituting the aqueous electrolyte, and good water permeability, which increases the amount of ions that pass through the separator. Therefore, by using this as a separator, it becomes possible to extract a large capacity even when the battery is discharged under a heavy load.

[0019] Furthermore, since the porous membrane has high air permeability and limited breathability to a certain extent, and also has a certain thickness, the occurrence of the micro-short circuit can be suppressed in a battery using this as a separator.

[0020] The aqueous electrolyte battery of the present invention is able to achieve both excellent load characteristics and high reliability due to the above-mentioned effects.

[0021] The porous membrane used as a separator in an aqueous electrolyte battery has a contact angle with water of 90° or less, preferably 70° or less, and particularly preferably 60° or less. If the porous membrane has a contact angle with water that satisfies this value and an air permeability within the range described below, using it as a separator will have high affinity with the aqueous electrolyte and good ion permeability, thereby improving the load characteristics of the battery. There is no particular limit to the lower limit of the contact angle with water of the porous membrane used as a separator, but it is usually 10° or more. In order to broaden the types of resins that can be used and the conditions for hydrophilization treatment, and to facilitate production, it is preferably 20° or more, and particularly preferably 30° or more.

[0022] The contact angle of a porous membrane with water referred to in this specification is a value measured from the side of the porous membrane after 1 minute from dropping 50 μL of ion-exchanged water onto the surface of the porous membrane. The contact angle can be measured using a general measuring device such as a dynamic contact angle meter "1100DAT" (product name) manufactured by Fibro.

[0023] The air permeability of a porous membrane used as a separator in an aqueous electrolyte battery is 3000 sec / 100 mL or less, preferably 1000 sec / 100 mL or less, and particularly preferably 600 sec / 100 mL or less. When the air permeability of a porous membrane satisfies these values ​​and the contact angle with water satisfies the above values, using it as a separator can improve the load characteristics of the battery, as described above. However, if a porous membrane with too low an air permeability is used as a separator, micro-short circuits in the battery are likely to occur. Therefore, from the viewpoint of suppressing the occurrence of micro-short circuits and improving battery reliability, the air permeability of a porous membrane used as a separator is 10 sec / 100 mL or more, preferably 20 sec / 100 mL or more, and particularly preferably 50 sec / 100 mL or more. When the separator is composed of multiple layers, each layer may be configured so that the air permeability of the separator as a whole is within the above range.

[0024] The air permeability of the porous membrane referred to in this specification is a value determined by the Gurley method specified in JIS P 8117.

[0025] Furthermore, the porous membrane used as the separator of an aqueous electrolyte battery has a thickness of 5 μm or more from the viewpoint of effectively suppressing the occurrence of micro-short circuits in the battery, and has a thickness of 100 μm or less, preferably 30 μm or less, from the viewpoint of suppressing a decrease in the volumetric capacity density of the battery due to an increase in the thickness of the separator.

[0026] The porous membrane used as a separator is made of resin. The resin that constitutes the porous membrane can be either one with high or low affinity for water, but it is preferable to use polyolefins (polyethylene (PE), polypropylene (PP), ethylene-propylene copolymers, etc.) that are commonly used for battery separators.

[0027] As the porous membrane, a microporous membrane made of the above-mentioned resin (a porous membrane called a "microporous membrane" that is generally used as a separator in a battery) can be used.

[0028] The porous membrane may be selected from porous membranes such as microporous membranes made of the resins described above, so as to satisfy the above-mentioned air permeability and thickness. In the case of a microporous membrane made of a resin, the air permeability can be adjusted by adjusting the porosity or tortuosity of the pores.

[0029] In addition, polyolefins and the like, which are suitable as the constituent resins of the porous membrane, have low affinity to water, and the porous membrane formed therefrom has a contact angle with water that exceeds the upper limit value. However, in the case of a porous membrane made of such a resin, if the contact angle with water satisfies the above value by performing a hydrophilization treatment, it can be used as a separator.

[0030] Examples of hydrophilization treatments for porous membranes include a method of introducing sulfonic acid groups into the constituent resin of the porous membrane by sulfuric acid treatment, and a method of treating with a reactive gas containing fluorine gas and oxygen atoms and / or sulfur atoms (both of these methods are disclosed in JP-A-2000-355633, etc.).Porous membranes can also be hydrophilized by general methods for hydrophilizing resin films, such as corona discharge treatment and atmospheric pressure plasma treatment.

[0031] The aqueous electrolyte battery of the present invention is not particularly limited in its configuration, as long as it uses an aqueous electrolyte and has the porous membrane as a separator. That is, the aqueous electrolyte battery of the present invention can take the form of various batteries having an aqueous electrolyte, such as alkaline batteries (alkaline primary batteries, alkaline secondary batteries), manganese batteries, and air batteries. Examples of such alkaline batteries include nickel-zinc batteries that use nickel oxyhydroxide as the positive electrode active material and a zinc-based material (a term that collectively refers to zinc materials and zinc alloy materials) as the negative electrode active material, and silver-zinc batteries that use silver oxide as the positive electrode active material and a zinc-based material as the negative electrode active material.

[0032] The electrolyte of an aqueous electrolyte battery is an aqueous solution in which an electrolyte salt is dissolved in water as a solvent. The aqueous solution used as the electrolyte is not particularly limited, and it is possible to use a high-concentration alkaline electrolyte (pH: approximately 14) used in alkaline dry batteries. However, from the viewpoints of reducing the environmental impact during disposal and ensuring safety in the event of leakage of the electrolyte due to damage to the exterior, it is preferable that the pH of the electrolyte be as close to neutral as possible. The pH is preferably 3 or higher, more preferably 5 or higher, and is preferably less than 12, more preferably 10 or lower. From the viewpoint of inhibiting corrosion of the negative electrode active material, it is even more preferable that the pH be less than 7.

[0033] Examples of the electrolyte salt of the aqueous solution used as the electrolyte 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 (lithium hydroxide, 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.), glutamates (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; polycarboxylic acids; and the aqueous solution may contain one or more of these electrolyte salts.

[0034] 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.

[0035] In the negative electrode of an aqueous electrolyte battery, a metallic material such as a metal or alloy is usually used as the negative electrode active material. However, an electrolyte consisting of an aqueous solution containing a salt of a strong acid and a weak base as exemplified above has a relatively weaker effect of corroding the metallic material that is the negative electrode active material than an electrolyte containing a salt of a strong acid and a strong base such as sodium chloride. Furthermore, among salts of strong acids, an electrolyte containing a salt of a metal element selected from Al, Mg, and Fe or an ammonium salt has a relatively high conductivity compared to, for example, an aqueous zinc chloride solution. Therefore, as a salt of a strong acid and a weak base, Cl - , SO4 2- , HSO4 - and NO3 - When an electrolyte solution consisting of 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 aqueous electrolyte battery can be further improved.

[0036] 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 has a weaker corrosive effect on the metal material that is the negative electrode active material.

[0037] 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).

[0038] 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).

[0039] Furthermore, when the aqueous electrolyte battery is an air battery, the aqueous solution usable as the electrolyte preferably contains a water-soluble high-boiling-point solvent with a boiling point of 150°C or higher as a solvent together with water. In an air battery, as the remaining capacity of the negative electrode decreases during discharge, the voltage decreases accordingly. However, in the later stages of discharge when the remaining capacity decreases, not only does the voltage decrease but the voltage fluctuations tend to become large. However, if the aqueous solution contains a water-soluble high-boiling-point solvent, the voltage fluctuations in the later stages of discharge can be suppressed, resulting in an air battery with better discharge characteristics. The upper limit of the boiling point of the water-soluble high-boiling-point solvent is usually 320°C.

[0040] The water-soluble high-boiling-point solvent preferably has a high surface tension and dielectric constant. Specific examples 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 with a molecular weight of 600 or less) such as PEG (e.g., boiling point 230°C, surface tension 43 mN / m, dielectric constant 35). The electrolyte solution may contain only one of these water-soluble high-boiling-point solvents or a combination of two or more of them, but it is more preferable to use glycerin.

[0041] When a water-soluble high-boiling solvent is used, the content of the water-soluble high-boiling solvent in the total solvent of the aqueous solution is preferably 1% by mass or more, 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 aqueous solution is too large, the ionic conductivity of the aqueous 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 aqueous solution is preferably 30% by mass or less, more preferably 20% by mass or less.

[0042] The concentration of the electrolyte salt in the aqueous solution may be, for example, a concentration that can adjust the conductivity of the aqueous solution to about 80 to 700 mS / cm, and is usually 5 to 50 mass %.

[0043] The aqueous solution used as the electrolyte preferably contains an indium compound dissolved in its solvent (water or a mixed solvent of water and a water-soluble high-boiling point solvent).When an indium compound is dissolved in the aqueous solution, the generation of hydrogen gas in the battery can be effectively suppressed.

[0044] 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.

[0045] 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.

[0046] In addition to the above components, various known additives may be added to the aqueous solution as needed, provided that 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.

[0047] The aqueous solution constituting the electrolyte may be gelled, and it is also preferable to use a gelled electrolyte (gelled electrolyte) obtained by blending an aqueous solution containing an electrolyte salt and having a pH of 3 or more but less than 12 with a thickener (sodium polyacrylate, carboxymethyl cellulose, etc.) as the electrolyte for an aqueous electrolyte battery. In this case, too, fluctuations in voltage during the latter stage of discharge can be suppressed, thereby further improving the discharge characteristics of the aqueous electrolyte battery. Furthermore, because water evaporation from the gelled electrolyte is suppressed, deterioration in discharge characteristics due to fluctuations in the electrolyte composition can be suppressed, particularly in air batteries with air holes formed in the exterior body, and the storage characteristics of the battery can also be further improved.

[0048] When the aqueous electrolyte battery is an alkaline battery or a manganese battery, the positive electrode may have a structure in which a positive electrode mixture layer containing a positive electrode active material, a conductive additive, and a binder is provided on one or both sides of a current collector.

[0049] Examples of usable positive electrode active materials when the aqueous electrolyte is an alkaline battery include silver oxide (silver (I) oxide, silver (II) oxide, etc.), manganese oxides such as manganese dioxide, nickel oxyhydroxide, composite oxides of silver and cobalt, nickel, or bismuth, etc. When the sheet-type battery is a manganese battery, manganese oxides such as manganese dioxide are used as the positive electrode active material.

[0050] Examples of the conductive additive for the positive electrode mixture layer that can be used include carbon materials such as acetylene black; ketjen black; carbon blacks such as channel black, furnace black, lamp black, and thermal black; and carbon fibers; as well as conductive fibers such as metal fibers; carbon fluoride; metal powders such as copper and nickel; and organic conductive materials such as polyphenylene derivatives.

[0051] Examples of binders for the positive electrode mixture layer include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), styrene butadiene rubber (SBR), carboxymethyl cellulose (CMC), and polyvinylpyrrolidone (PVP).

[0052] The positive electrode mixture layer preferably contains 80 to 98% by mass of positive electrode active material, 1.5 to 10% by mass of conductive additive, and 0.5 to 10% by mass of binder. The thickness of the positive electrode mixture layer (thickness per surface of the current collector) is preferably 30 to 300 μm.

[0053] A positive electrode having a positive electrode mixture layer can be manufactured, for example, by dispersing a positive electrode active material, a conductive additive, a binder, and the like in water or an organic solvent such as N-methyl-2-pyrrolidone (NMP) to prepare a positive electrode mixture-containing composition (slurry, paste, etc.) (the binder may be dissolved in the solvent), applying this to a current collector, drying it, and, if necessary, performing a pressing process such as a calendaring process.

[0054] When the aqueous electrolyte battery is an air battery, the positive electrode may have a catalyst layer, for example, a structure in which a catalyst layer and a current collector are laminated.

[0055] The catalyst layer may contain a catalyst, a binder, and the like.

[0056] 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, La1-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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] The catalyst content in the catalyst layer is preferably 20 to 70 mass %.

[0062] 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.

[0063] A positive electrode having a catalyst layer can be produced, for example, by mixing the catalyst, binder, etc. with water, rolling the mixture with a roll, and then adhering it to a current collector. Alternatively, the positive electrode can be produced by dispersing the catalyst and optionally a binder, etc., 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 it, and then optionally performing a pressing process such as calendering.

[0064] The current collector for a positive electrode having a positive electrode mixture layer or a positive electrode having a catalyst layer can be made of, for example, a mesh, foil, expanded metal, or punched metal made of metal such as titanium, nickel, stainless steel, or copper; a carbon mesh or sheet; etc. The thickness of the current collector for the positive electrode is preferably 10 μm or more and 300 μm or less.

[0065] Furthermore, when a sheet-like resin film outer casing (described in detail below) is used as the outer casing of the battery, the resin film constituting the sheet-like outer casing can also be used as the current collector for the positive electrode. In this case, for example, a carbon paste is applied to the surface of the resin film that is intended to become the inner surface of the sheet-like outer casing to form a current collector, and a positive electrode mixture layer and a catalyst layer are 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.

[0066] The negative electrode of an aqueous electrolyte battery contains a metal material such as a zinc-based material (zinc or zinc alloy), a magnesium-based material (magnesium or magnesium alloy), or an aluminum-based material (aluminum or aluminum alloy). In such a negative electrode, the metal, such as zinc, magnesium, or aluminum, acts as the active material.

[0067] 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.

[0068] Specific examples of negative electrodes containing metal materials include metal sheets such as sheets made of the above materials (zinc foil, zinc alloy foil, magnesium foil, magnesium alloy foil, aluminum foil, aluminum alloy foil, etc.) The thickness of such negative electrodes is preferably 10 to 500 μm.

[0069] Examples of alloying components of zinc alloys include indium, bismuth, and aluminum, and alloys containing one or more of these elements are used.

[0070] The zinc alloy may have an indium content of, for example, 0.005% or more and 0.1% or less by mass, a bismuth content of, for example, 0.002% or more and 0.2% or less by mass, and an aluminum content of, for example, 0.001% or more and 0.15% or less by mass.

[0071] Zinc foil (zinc alloy foil) includes electrolytic zinc foil and rolled zinc foil, but electrolytic zinc foil is preferably used because electrolytic zinc foil is less likely to generate gas due to reaction with the electrolyte in the battery, and electrolytic zinc foil containing bismuth is more preferably used. The preferred range of the bismuth content in electrolytic zinc foil is 0.02% or more and 0.1% or less by mass.

[0072] Furthermore, examples of alloying components of magnesium alloys include calcium, manganese, zinc, and aluminum, and alloys containing one or more of these elements are used.

[0073] The calcium content in the magnesium alloy is, for example, 1% or more and 3% or less by mass. The manganese content is, for example, 0.1% or more and 0.5% or less by mass. The zinc content is, for example, 0.4% or more and 1% or less by mass. The aluminum content is, for example, 8% or more and 10% or less by mass.

[0074] Furthermore, examples of alloying components of the aluminum alloy include zinc, tin, gallium, silicon, iron, magnesium, and manganese, and an alloy containing one or more of the above elements is used.

[0075] The zinc content in the aluminum alloy is, for example, 0.5% or more and 10% or less by mass. The tin content is, for example, 0.04% or more and 1.0% or less by mass. The gallium content is, for example, 0.003% or more and 1.0% or less by mass. The silicon content is, for example, 0.05% or less by mass. The iron content is, for example, 0.1% or less by mass. The magnesium content is, for example, 0.1% or more and 2.0% or less by mass. The manganese content is, for example, 0.01% or more and 0.5% or less by mass.

[0076] Specific examples of negative electrodes containing a metal material include negative electrodes containing metal particles such as particles made of the above-mentioned materials.

[0077] In the case of a negative electrode containing metal particles, the metal particles may be of one type alone or two or more types.

[0078] Regarding the particle size of the zinc-based material, 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.

[0079] Regarding the particle size of the magnesium-based material particles and aluminum-based material 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.

[0080] 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 )

[0081] In the case of a negative electrode containing the above-mentioned metal particles, a gelling agent (such as polyethylene oxide, sodium polyacrylate, or carboxymethyl cellulose) or a binder may be added as needed, and a negative electrode agent (such as a gelled negative electrode) can be used by adding an electrolyte solution to the above. The amount of gelling agent in the negative electrode is preferably 0.5 to 1.5 mass %, and the amount of binder is preferably 0.5 to 3 mass %.

[0082] The electrolyte for the negative electrode containing metal particles can be the same as that injected into the battery.

[0083] 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.

[0084] 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 electrolyte.

[0085] Examples of the indium compound include indium oxide and indium hydroxide.

[0086] 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.

[0087] 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.

[0088] When a sheet-like outer casing made of a resin film is used as the outer casing of the battery, the negative electrode current collector can be used by applying a carbon paste to the surface that is to become the inner surface of the sheet-like outer casing, as in the case of the positive electrode. The thickness of the carbon paste layer is preferably 50 to 200 μm.

[0089] There are no particular limitations on the form of the aqueous electrolyte battery, and it can be any form, such as a flat type (including a coin type and a button type) having a battery case in which the outer can and the sealing plate are crimped and sealed via a gasket, or the outer can and the sealing plate are sealed by welding; a sheet type having a sheet-like outer body made of a resin film; or a cylindrical type (cylindrical or prismatic (rectangular cylindrical)) having a battery case in which the outer can and the sealing plate are crimped and sealed via a gasket, or the outer can and the sealing plate are sealed by welding.

[0090] When the aqueous electrolyte battery is used as a power source for medical and health-related devices, such as a patch that can be worn on the body, particularly a patch that is worn on the surface of the skin to measure body conditions such as body temperature, pulse rate, and sweat rate, it is preferable to use a sheet-type battery with a sheet-type outer casing made of a resin film.

[0091] The sheet-like outer packaging body is made of a resin film, and examples of such a resin film include nylon film (such as nylon 66 film) and polyester film (such as polyethylene terephthalate (PET) film).

[0092] In general, sealing of the sheet-like outer packaging body is performed by heat-sealing the edges of the upper and lower resin films 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 as the sheet-like outer packaging body. The separator may also be sandwiched between the upper and lower heat-sealing resin layers and heat-sealed. 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 200 μm.

[0093] 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.

[0094] Furthermore, the resin film constituting the sheet-like outer packaging body may be a film having a configuration in which the above-mentioned heat-sealable resin layer and the above-mentioned metal layer are laminated together.

[0095] It is also preferable that the resin film constituting the sheet-like exterior body has an electrically insulating water vapor barrier layer. In this case, the electrically insulating resin film may have a single-layer structure in which it itself also serves as a water vapor barrier layer, or a multilayer structure in which it has multiple electrically insulating resin film layers, at least one of which serves as a water vapor barrier layer, or a multilayer structure in which an electrically insulating water vapor barrier layer is provided on the surface of a base layer made of a resin film.

[0096] Among such resin films, those in which a water vapor barrier layer made of at least an inorganic oxide is formed on the surface of a base layer made of a resin film are preferably used.

[0097] Examples of inorganic oxides constituting the water vapor barrier layer include aluminum oxide and silicon oxide. Note that a water vapor barrier layer made of silicon oxide tends to have a higher function of suppressing the permeation of moisture in the electrolyte solution in the battery than a water vapor barrier layer made of aluminum oxide. Therefore, it is more preferable to use silicon oxide as the inorganic oxide constituting the water vapor barrier layer.

[0098] The water vapor barrier layer made of an inorganic oxide can be formed on the surface of the substrate layer by, for example, a vapor deposition method. The thickness of the water vapor barrier layer is preferably 10 to 300 nm.

[0099] The base layer of the resin film having a water vapor barrier layer may be the above-mentioned nylon film or polyester film, or may be a polyolefin film, polyimide film, polycarbonate film, etc. The thickness of the base layer is preferably 5 to 100 μm.

[0100] In the case of a resin film having a water vapor barrier layer and a base layer, a protective layer for protecting the water vapor barrier layer may be formed on the surface of the water vapor barrier layer (the surface opposite to the base layer).

[0101] Furthermore, in the case of a resin film having a water vapor barrier layer and a substrate layer, the above-mentioned heat-sealable resin layer may be further laminated thereon.

[0102] The overall thickness of the resin film is preferably 10 μm or more from the viewpoint of providing sufficient strength to the battery, and is preferably 200 μm or less from the viewpoint of preventing an increase in the battery thickness and a decrease in energy density.

[0103] The water vapor permeability of the resin film that constitutes the sheet-like outer packaging is 10 g / m 2 It is preferable that the resin film does not transmit water vapor as much as possible, that is, the water vapor transmission rate is preferably as low as possible, and is preferably 0 g / m 2· May be 24 hours.

[0104] The water vapor permeability of the resin film referred to in this specification is a value measured in accordance with JIS K 7129B method.

[0105] In addition, when the aqueous electrolyte battery is an air battery, it is preferable that the resin film constituting the sheet-like outer casing has a certain degree of oxygen permeability. Air batteries discharge by supplying air (oxygen) to the positive electrode, so air holes for introducing oxygen into the battery are formed in the sheet-like outer casing. However, if the resin film constituting the sheet-like outer casing has oxygen permeability, oxygen can be introduced into the battery through the outer casing at locations other than the air holes in the sheet-like outer casing. This allows oxygen to be supplied more uniformly throughout the positive electrode, improving the battery's discharge characteristics and extending its discharge time. It is also possible to realize a sheet-like air battery without air holes in the sheet-like outer casing.

[0106] When the aqueous electrolyte battery is an air battery, the specific oxygen permeability of the resin film that constitutes the sheet-like outer casing is 0.02 cm 3 / m 2 ·24h·MPa or more is preferable, and 0.2cm 3 / m 2 However, if the battery is an air battery, if the resin film constituting the sheet-like outer casing is permeable to too much oxygen, self-discharge may occur and the capacity may be lost. Therefore, the oxygen permeability of the resin film should be 100 cm 3 / m 2 ·24h·MPa or less is preferable, and 50cm 3 / m 2 It is more preferable that the compressive strength is 24h MPa or less.

[0107] On the other hand, when the aqueous electrolyte battery is a battery other than an air battery, there is no particular restriction on the oxygen permeability of the resin film constituting the sheet-like outer casing. However, from the viewpoint of improving the storage life of the battery, it is preferable that the resin film does not allow much oxygen to permeate. The oxygen permeability of a specific resin film is 10 cm 3 / m 2 ·24h·MPa or less is preferable.

[0108] The oxygen permeability of the resin film referred to in this specification is a value measured in accordance with JIS K 7126-2 method.

[0109] Furthermore, when using an exterior body that is crimp-sealed, the material of the gasket interposed between the exterior can and the sealing plate can be a material that is used for alkaline batteries, such as polypropylene or nylon.

[0110] Furthermore, to prevent elements such as iron that make up the outer can from eluting during charging, it is desirable to plate the inner surface of the outer can with a corrosion-resistant metal such as tin, zinc, or indium.

[0111] An example of the aqueous electrolyte battery of the present invention is shown schematically in Figures 1 and 2. Figures 1 and 2 show an example in which the aqueous electrolyte battery is an air battery having a sheet-like outer casing (sheet-like air battery), with Figure 1 showing a plan view and Figure 2 showing a cross-sectional view taken along line II in Figure 1.

[0112] As shown in Fig. 2, in the aqueous electrolyte battery 1, a positive electrode 10, a separator 30, a negative electrode 20, and an electrolyte (not shown) are housed in a sheet-like outer casing 50. The dotted line in Fig. 1 indicates the size of the positive electrode 10 housed in the sheet-like outer casing 50 (the size of the wide main body excluding the terminal portion, which corresponds to the size of the catalyst layer of the positive electrode).

[0113] A terminal portion 10a of the positive electrode 10 and a terminal portion 20a of the negative electrode 20 protrude from the upper side of the sheet-like exterior body 50 in the figure. These terminal portions 10a, 20a are used as external terminals for electrically connecting the aqueous electrolyte battery 1 to an applicable device.

[0114] The sheet-like outer casing 50 has a plurality of air holes 51 on one side where the positive electrode 10 is placed, for taking in air into the positive electrode, and a water-repellent film 40 is placed on the sheet-like outer casing 50 side of the positive electrode 10 to prevent leakage of the electrolyte from the air holes 51.

[0115] The positive electrode 10 has a catalyst layer, and as described above, for example, has a structure in which the catalyst layer is laminated with a current collector, but in order to avoid complicating the drawing, the layers of the positive electrode 10 are not distinguished in Fig. 2. Also, in Fig. 2, the sheet-like outer casing 50 (the resin film constituting it) is shown as having a single-layer structure, but as described above, the resin film constituting the sheet-like outer casing can also have a multilayer structure.

[0116] The terminal portion of the positive electrode may be provided by a positive electrode current collector having a shape including a main portion where the positive electrode mixture layer and the catalyst layer are formed and an exposed portion where the positive electrode mixture layer and the catalyst layer are not formed, or may be provided by attaching a separate lead body to the positive electrode current collector by welding or the like.

[0117] Furthermore, in the case of a negative electrode having a negative electrode current collector, the terminal portion of the negative electrode can also be formed by forming the negative electrode current collector into a shape having a main portion where a layer containing a negative electrode active material or the like is formed and an exposed portion where this layer is not formed, and providing the terminal portion using this exposed portion, or by attaching a separate lead body to the negative electrode current collector by welding or the like.

[0118] In addition, when the negative electrode is composed of a metal sheet, the metal sheet can be cut into a shape having a main body portion and a terminal portion that function as a negative electrode active material layer, thereby forming a negative electrode having a main body portion and a terminal portion from a single metal sheet.

[0119] The shape of the sheet-like outer casing may be polygonal (triangle, quadrangle, pentagon, hexagon, heptagon, or octagon) in plan view, 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 terminal and the negative electrode terminal may be led out from the same side or from different sides.

[0120] When the aqueous electrolyte battery is an air battery, a water-repellent film is usually disposed between the positive electrode and the exterior body, as shown in Fig. 2. The water-repellent film 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.

[0121] Furthermore, when the aqueous electrolyte battery is an air battery, 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.

[0122] When the aqueous electrolyte battery is a sheet-type battery, there are no particular restrictions on its thickness (the length of a in FIG. 2) and it can be changed as appropriate depending on the intended use of the battery. One advantage of sheet-type batteries is that they can be made thin, and from this perspective, it is preferable that the thickness is, for example, 1 mm or less. When the aqueous electrolyte battery is a sheet-type air battery, it is particularly easy to provide such a thin battery.

[0123] There is no particular lower limit to the thickness of the sheet-type battery, but it is usually preferable to set it to 0.2 mm or more in order to ensure a certain capacity. [Example]

[0124] The present invention will be described in detail below based on examples, but the present invention is not limited to these examples.

[0125] 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.

[0126] A porous carbon paper (thickness: 0.25 mm, porosity: 75%) was used as a current collector, and the catalyst layer-forming composition was applied in an amount of 10 mg / cm after drying. 2 The 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 15 mm x 15 mm and a lead portion measuring 5 mm x 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.

[0127] <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 15 mm × 15 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.

[0128] <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 air 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 and 3 and Comparative Examples 1 to 3 described below.

[0129] <separator> The separator used was a hydrophilized PE microporous membrane (thickness: 16 μm, air permeability: 45 sec / 100 mL, contact angle with water: 65°). The hydrophilization of the PE microporous membrane was carried out by introducing sulfonic acid groups into the PE constituting the microporous membrane through sulfuric acid treatment, followed by treatment with a mixed gas containing fluorine gas, oxygen, sulfur dioxide, and nitrogen.

[0130] <Water-repellent film> The water-repellent film was a PTFE sheet with a thickness of 200 μm.

[0131] <Battery assembly> Two sheets of 25 mm x 25 mm aluminum laminate film (thickness: 65 μm) having a PET film on the outer surface of the aluminum foil and a PP film as a heat-sealable resin layer on the inner surface were used as the exterior body.

[0132] One of the exterior bodies, located on the positive electrode side, had nine 0.2 mm diameter air holes formed in a regular pattern of three holes spaced equally apart (5 mm center-to-center distance between air holes) measuring 4.8 mm long x 4.8 mm wide, 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.

[0133] 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 seal the opening, completing a sheet-like air battery (aqueous electrolyte battery).

[0134] Example 2 A sheet-type air battery was produced in the same manner as in Example 1, except that the separator was changed to a microporous PE membrane that had been hydrophilized in the same manner as in Example 1, with a thickness of 20 μm, an air permeability of 150 sec / 100 mL, and a contact angle with water of 63°.

[0135] Example 3 A sheet-type air battery was produced in the same manner as in Example 1, except that the separator was changed to a PE / PP / PE microporous membrane (a three-layer microporous membrane having a PE layer on both sides of a PP layer) that had been hydrophilized in the same manner as in Example 1, with a thickness of 25 μm, an air permeability of 550 sec / 100 mL, and a contact angle with water of 63°.

[0136] Comparative Example 1 A sheet-type air battery was fabricated in the same manner as in Example 1, except that the separator was changed to a PP nonwoven fabric having a thickness of 100 μm and an air permeability of 2 sec / 100 mL, which had been hydrophilized in the same manner as in Example 1. The contact angle of this hydrophilized PP nonwoven fabric with water could not be measured because the dropped ion-exchanged water immediately soaked into the nonwoven fabric.

[0137] Comparative Example 2 A sheet-type air battery was fabricated in the same manner as in Example 1, except that the separator was changed to one in which two graft films (thickness per film: 15 μm) composed of a graft copolymer having a structure in which acrylic acid was graft copolymerized onto a PE main chain were placed on both sides of a cellophane film (thickness: 20 μm) (total thickness: 50 μm). The air permeability of the entire separator was a value exceeding the upper limit of measurement (>3000 sec / 100 mL).

[0138] Comparative Example 3 A sheet-type air battery was fabricated in the same manner as in Example 1, except that the separator was changed to a PE microporous membrane (thickness: 16 μm, air permeability: 150 sec / 100 mL, contact angle with water: 102°) that had not been hydrophilized.

[0139] The sheet-shaped air batteries of the Examples and Comparative Examples were evaluated as follows.

[0140] [Pulse discharge test (load characteristics evaluation)] For each of the sheet-shaped air batteries of the Examples and Comparative Examples, a pulse discharge test was carried out 50 times under the conditions of a current value of 30 mA, a pulse width of 10 msec, and a pulse interval of 3 sec, and the closed circuit voltage (CCV) was measured.

[0141] [OCV measurement before and after load test (reliability evaluation)] A 5 kg weight was placed on each of the sheet-air batteries of the Examples and Comparative Examples whose open circuit voltages (OCV) had been measured, and a load test was carried out for 30 days at 20° C. Then, the OCV of each battery after the load test was measured.

[0142] The configurations of the separators used in the sheet-type air batteries of the Examples and Comparative Examples are shown in Table 1, and the evaluation results are shown in Table 2. In Table 1, "-" in the "Contact angle with water" column means that the contact angle with water could not be measured.

[0143] [Table 1]

[0144] [Table 2]

[0145] As shown in Tables 1 and 2, the sheet-type air batteries of Examples 1 to 3, which used a resin porous membrane with suitable thickness, air permeability, and water contact angle as a separator, had high CCV during pulse discharge and good load characteristics.In addition, the change in OCV before and after the load test was small, the occurrence of micro-short circuits due to the application of load was suppressed, and they also had excellent reliability.

[0146] In contrast, the battery of Comparative Example 1, which used a separator with a porous membrane (a hydrophilized PP nonwoven fabric) with too little air permeability, showed a large decrease in OCV during the load test and was therefore poor in reliability. Furthermore, the battery of Comparative Example 2, which used a separator with too much air permeability, consisting of a laminated graft film and a cellophane film (both of which have no pores), and the battery of Comparative Example 3, which used a separator with a porous membrane with too large a contact angle with water, both showed low CCV during pulse discharge and poor load characteristics.

[0147] The present invention can be implemented in other forms without departing from the spirit of the present invention. The embodiments disclosed in this application are merely examples, and the present invention is not limited to these embodiments. The scope of the present invention shall be interpreted in accordance with the appended claims rather than the description in the above specification, and all modifications within the scope of the claims are included in the scope of the claims. [Industrial Applicability]

[0148] The aqueous electrolyte battery of the present invention has a small environmental impact when the electrolyte is an aqueous solution, particularly when the aqueous solution has a suitable pH of 3 or more but less than 12. Furthermore, even if the electrolyte leaks due to breakage or other reasons and comes into contact with the body, problems are unlikely to occur. Therefore, the aqueous electrolyte battery of the present invention is suitable as a power source for medical and healthcare devices, such as patches that can be worn on the body, particularly patches worn on 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 batteries (primary batteries) containing aqueous electrolytes, such as air batteries and alkaline batteries. [Explanation of symbols]

[0149] 1 Aqueous electrolyte battery 10 Positive electrode (air electrode) 10a Positive electrode terminal 20 negative electrode 20a Negative electrode terminal 30 Separator 40 Water-repellent film 50 Sheet-shaped outer packaging 51 Air vent

Claims

1. A battery comprising a positive electrode, a negative electrode containing a metal material, a separator, and an aqueous electrolyte solution housed in an exterior body, the separator is a porous film made of resin, having a thickness of 5 μm or more and 100 μm or less, an air permeability of 10 sec / 100 mL or more and 3000 sec / 100 mL or less, and a contact angle with water of 90° or less, The aqueous electrolyte battery is characterized in that the negative electrode has an electrolytic zinc foil made of a zinc alloy containing 0.02 mass % or more and 0.1 mass % or less of bismuth.

2. 2. The aqueous electrolyte battery according to claim 1, wherein the separator has a contact angle with water of 70° or less.

3. 3. The aqueous electrolyte battery according to claim 1, wherein the separator has an air permeability of 10 sec / 100 mL or more and 1000 sec / 100 mL or less.

4. 4. The aqueous electrolyte battery according to claim 1, wherein the separator has a thickness of 5 μm or more and 30 μm or less.

5. 5. The aqueous electrolyte battery according to claim 1, wherein the porous membrane is made of polyolefin.

6. 6. The aqueous electrolyte battery according to claim 5, wherein the porous membrane is made of polyethylene or polypropylene.

7. 7. The aqueous electrolyte battery according to claim 1, which is an air battery.

8. 8. The aqueous electrolyte battery according to claim 1, which is a sheet-type battery having a resin film as an exterior body.

9. 9. The aqueous electrolyte battery according to claim 1, wherein the aqueous electrolyte has a pH of 3 or more and less than 12.

10. A patch that can be attached to the body, comprising the aqueous electrolyte battery according to any one of claims 1 to 9 as a power source.

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