Liquid Detection Sensor

Abstract

To provide a versatile liquid detection sensor in which deterioration of a metal-air battery acting as a power source can be prevented even after being installed for prolonged period of time, and allows the metal-air battery acting as the power source to exhibit superior power generating performance.SOLUTION: A liquid detection sensor provided herein has a metal-air battery comprising a positive electrode, a negative electrode, and an electrolyte component provided in the positive electrode, wherein the electrolyte component is encapsulated in bags made of resin having solubility or dispersibility in a detection target liquid.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a liquid detection sensor equipped with a metal-air battery, and more particularly to a liquid detection sensor having excellent power generation performance and excellent long-term storage properties. [Background technology]

[0002] Liquid detection sensors that detect leakage or flooding are sometimes used in buildings, underground facilities, factories, medical facilities, etc. The liquid detection sensors are placed in locations where leakage or flooding must be prevented. The liquid detection sensor detects leakage by capturing electrical changes that occur when liquid comes into contact with the battery in the liquid detection sensor from the outside.

[0003] One example of a liquid detection sensor is a liquid detection sensor for use in medical settings that is equipped with a water cell that generates electricity from leaked liquid (Patent Document 1). In Patent Document 1, the water cell is fixed onto an absorbent member with adhesive fixing tape, and when liquid such as blood or intravenous fluid that has been absorbed and diffused into the absorbent member is supplied to the entire water cell, the water cell generates electricity and detects liquid leakage.

[0004] Another example of a liquid detection sensor is a liquid detection sensor for use in medical settings that includes a liquid leakage sensor unit made of a magnesium battery (Patent Document 2). In Patent Document 2, the magnesium battery is formed by sequentially laminating a positive electrode sheet, a catalyst sheet, a sheet-like separator, and a negative electrode sheet, and includes a transmitter that is electrically connected to the liquid leakage sensor unit and transmits a detection signal using the power of the magnesium battery, a receiver that receives the detection signal transmitted from the transmitter, and a receiver terminal that has an alarm means for alarming a liquid leakage state based on the detection signal from the receiver. The liquid leakage sensor unit detects, as a liquid leakage state, a state in which the magnesium battery generates electricity using blood or injection fluid leaked from the injection needle as an electrolyte.

[0005] It is necessary to detect liquid leakage with high accuracy, but the liquid detection sensors in Patent Documents 1 and 2, in which the detection target, such as blood, functions as an electrolyte, are not proposed for use in any other applications than the detection of blood in medical settings, and therefore lack versatility.

[0006] On the other hand, detection of liquid leakage and flooding is required not only in medical settings but also in a wide range of fields such as buildings, underground facilities, factories, flood control, etc., and therefore liquid detection sensors are required to have versatility such as the ability to detect water, oil, etc. However, as described above, the liquid detection sensors in Patent Documents 1 and 2 have problems with versatility.

[0007] In order to make the liquid detection sensor more versatile, when monitoring leaks or flooding in buildings, underground facilities, factories, etc., or flooding around rivers using the liquid detection sensor, monitors may monitor from a location away from the site of the leak or flooding. In order for the liquid detection sensor to reliably transmit an alarm to a location away from the site of the leak or flooding, it is necessary to improve the power generation performance of the battery mounted in the liquid detection sensor.

[0008] When a metal-air battery is used as a power source mounted on a liquid detection sensor, the power generation performance of the metal-air battery can be improved by using an alkali metal salt such as sodium chloride or potassium chloride as an electrolyte. For example, if an alkali metal salt is impregnated in the separator of the metal-air battery in advance, when the separator containing the alkali metal salt comes into contact with water, which is the liquid to be detected, the water containing the alkali metal salt acts to improve the ionic conductivity between the positive and negative electrodes, allowing the metal-air battery to exhibit excellent power generation performance.

[0009] However, if the liquid detection sensor is left installed for a long period of time with the separator containing alkali metal salt, the alkali metal salt in the separator may absorb moisture and liquefy, causing deterioration of the negative electrode of the metal-air battery. If the negative electrode of the metal-air battery deteriorates while the liquid detection sensor is installed for a long period of time, there is a problem that leakage or flooding cannot be detected accurately. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] International Publication No. 2012 / 020507 [Patent Document 2] JP 2017-148332 A Summary of the Invention [Problem to be solved by the invention]

[0011] In view of the above circumstances, an object of the present invention is to provide a liquid detection sensor that is versatile, can prevent deterioration of the metal-air battery that is its power source even when installed for a long period of time, and allows the metal-air battery that is its power source to exhibit excellent power generation performance. [Means for solving the problem]

[0012] The gist of the configuration of the present invention is as follows. [1] A metal-air battery having a positive electrode, a negative electrode, and an electrolyte component disposed on the positive electrode, The liquid detection sensor comprises a resin bag in which the electrolyte constituent components are sealed, and the resin of the resin bag has solubility or dispersibility in the liquid to be detected. [2] The liquid detection sensor according to [1], wherein the resin of the resin bag body is a water-soluble resin or an oil-soluble resin. [3] The liquid detection sensor according to [1] or [2], wherein the resin bag in which the electrolyte constituent components are sealed is one or more. [4] The liquid detection sensor according to any one of [1] to [3], wherein at least a portion of the resin bag in which the electrolyte constituent components are sealed is disposed inside the positive electrode. [5] The liquid detection sensor according to any one of [1] to [4], wherein the resin bag in which the electrolyte constituents are sealed is supported on the positive electrode. [6] The liquid detection sensor according to any one of [1] to [5], wherein the resin bag in which the electrolyte constituents are sealed is integrally formed with the positive electrode. [7] The liquid detection sensor according to any one of [1] to [6], comprising an extrusion material of a mixture of the positive electrode material and the resin bag in which the electrolyte constituents are sealed. [8] The liquid detection sensor according to any one of [1] to [7], wherein the electrolyte constituent components include water, an alkali metal salt, or an aqueous solution of an alkali metal salt. [9] The liquid detection sensor according to any one of [1] to [8], wherein the active material of the negative electrode contains at least one metal selected from the group consisting of magnesium (Mg), aluminum (Al), lithium (Li), calcium (Ca) and zinc (Zn).

[10] The liquid detection sensor according to any one of [1] to [9], comprising an alarm unit that receives power from the metal-air battery and notifies of the detection of liquid.

[11] The liquid detection sensor according to any one of [1] to [9], further comprising an alarm unit capable of wirelessly transmitting a detection signal of the metal-air battery to a receiving unit.

[12] The liquid detection sensor according to any one of [1] to

[11] , which is a water detection sensor.

[13] The liquid detection sensor according to any one of [1] to

[11] , which is an oil detection sensor.

[0013] In the above aspect [1], when the liquid to be detected by the liquid detection sensor comes into contact with the resin bag of the metal-air battery, the resin of the resin bag dissolves or disperses in the liquid to be detected, causing the electrolyte components sealed inside the resin bag to be released from the positive electrode of the metal-air battery to between the positive and negative electrodes. The release of the electrolyte components between the positive and negative electrodes of the metal-air battery improves the power generation or power generation performance of the metal-air battery, and the liquid detection sensor notifies the outside that the liquid to be detected has been detected by the metal-air battery generating electricity. Effect of the Invention

[0014] According to the embodiment of the liquid detection sensor of the present invention, the electrolyte components of the metal-air battery, which is the power source, are sealed inside a resin bag having solubility or dispersibility in the liquid to be detected, and by appropriately selecting the type of resin of the resin bag, the versatility of the sensor is improved, such as for detecting water or oil. According to the embodiment of the liquid detection sensor of the present invention, the electrolyte components of the metal-air battery are sealed inside a resin bag, and therefore the metal-air battery can be prevented from deteriorating due to the electrolyte components even if the liquid detection sensor is installed for a long period of time. According to the embodiment of the liquid detection sensor of the present invention, the electrolyte components of the metal-air battery are sealed inside a resin bag, and therefore electrolyte components that impart excellent power generation performance to the metal-air battery while preventing deterioration of the metal-air battery can be used, and therefore the metal-air battery can exhibit excellent power generation performance, and an alarm can be reliably transmitted to a place away from the site of the liquid leakage or flooding. Therefore, the liquid detection sensor of the present invention can reliably transmit an alarm to a place away from the site of the liquid leakage or flooding, and therefore the versatility is improved.

[0015] According to an aspect of the liquid detection sensor of the present invention, the resin of the resin bag body is a water-soluble resin, so that it functions as a water detection sensor that can more reliably detect the target water, and because the resin of the resin bag body is an oil-soluble resin, it functions as an oil detection sensor that can more reliably detect the target oil.

[0016] According to an embodiment of the liquid detection sensor of the present invention, since there are multiple resin bags in which the electrolyte components are sealed, the electrolyte components are smoothly supplied to the entire positive electrode, thereby improving the power generation efficiency of the metal-air battery. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a side view illustrating an overview of a liquid detection sensor according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a side view illustrating a state when the liquid detection sensor according to the first embodiment of the present invention detects liquid. [Diagram 3]FIG. 6 is a side view illustrating an overview of a liquid detection sensor according to a second embodiment of the present invention. [Figure 4] FIG. 11 is a side view illustrating a state when a liquid is detected by the liquid detection sensor according to the second embodiment of the present invention. [Diagram 5] 1 is an explanatory diagram of an example of a method of using the liquid detection sensor of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The liquid detection sensor according to the embodiment of the present invention will be described in detail below. First, the liquid detection sensor according to the first embodiment of the present invention will be described. Note that Fig. 1 is a side view for explaining the outline of the liquid detection sensor according to the first embodiment of the present invention, and Fig. 2 is a side view for explaining the state of the liquid detection sensor according to the first embodiment of the present invention when detecting liquid.

[0019] 1, the liquid detection sensor 1 according to the first embodiment of the present invention includes a metal-air battery 10 and an alarm unit 100 connected to the metal-air battery 10 via an electric wire unit 101. The alarm unit 100 has a function of notifying the detection of liquid by an alarm means when it receives electric power generated by the metal-air battery 10 via the electric wire unit 101.

[0020] The metal-air battery 10 includes a positive electrode 11, a negative electrode 12 facing the positive electrode 11, and a separator 13 located between the positive electrode 11 and the negative electrode 12. In the metal-air battery 10 of the liquid detection sensor 1, the positive electrode 11, the separator 13, and the negative electrode 12 are all in a sheet shape, and have a laminate structure in which the positive electrode 11, the separator 13, and the negative electrode 12 are stacked in this order. In addition, the peripheral portion 14 of the separator 13 extends outward beyond the positive electrode 11 and the negative electrode 12, and is exposed from the positive electrode 11 and the negative electrode 12. The separator 13 functions as a support member that supports the positive electrode 11 and the negative electrode 12 at a predetermined interval to prevent a short circuit caused by contact between the positive electrode 11 and the negative electrode 12.

[0021] In the metal-air battery 10, an electrolyte component 20 is disposed in the positive electrode 11. That is, the electrolyte component 20 is present in the positive electrode 11. The electrolyte component 20 is a component that constitutes the electrolyte of the metal-air battery 10 or is the electrolyte of the metal-air battery 10. The metal-air battery 10 starts self-power generation when the positive electrode 11 and the negative electrode 12 come into contact with the electrolyte.

[0022] As shown in FIG. 1, the electrolyte solution constituent 20 is sealed inside a resin bag 21. Therefore, the electrolyte solution constituent 20 is not in contact with any of the positive electrode 11, the separator 13, and the negative electrode 12. The resin bag 21 may be, for example, a thin film bag-shaped member, a film-shaped bag-shaped member, or a capsule-shaped member such as a microcapsule. The resin bag 21 contains the electrolyte solution constituent 20 and seals and packages a certain amount of the electrolyte solution constituent 20. Therefore, the resin bag 21 functions as a shell.

[0023] In the metal-air battery 10, there are a plurality of resin bags 21 in which the electrolyte constituent 20 is sealed, and the electrolyte constituent 20 is divided into a plurality of parts by a certain amount and sealed inside each of the resin bags 21. At least a part of the plurality of resin bags 21, 21, 21, . . . in which the electrolyte constituent 20 is sealed is disposed inside the positive electrode 11. The resin bag 21 in which the electrolyte constituent 20 is sealed is disposed inside the positive electrode 11, so that the electrolyte constituent 20 is present in the positive electrode 11. The resin bag 21 in which the electrolyte constituent 20 is sealed is disposed in a dispersed state on the surface and inside of the positive electrode 11. In the liquid detection sensor 1 of FIG. 1, a plurality of resin bags 21, 21, 21, . . . in which the electrolyte constituent 20 is sealed are disposed over the entire positive electrode 11.

[0024] The resin bag 21 is formed of a resin that is soluble or dispersible in the liquid to be detected by the liquid detection sensor 1. When the liquid to be detected by the liquid detection sensor 1 is water or a liquid containing water, the resin bag 21 is formed of, for example, a water-soluble resin. By forming the resin bag 21 from a water-soluble resin, the liquid detection sensor 1 functions as a water detection sensor.

[0025] An example of the water-soluble resin is a resin composition containing 100 parts by mass of a polyvinyl alcohol-based resin (A) containing copolymer units consisting of sulfonic acid groups or carboxyl groups, and 3 to 100 parts by mass of an addition reaction product (B) obtained by addition reaction of 1 to 4 moles of alkylene oxide to 1 mole of a trihydric to hexahydric polyhydric alcohol.

[0026] The polyvinyl alcohol resin (A) is a saponification product of a polyvinyl ester containing a copolymer unit consisting of a sulfonic acid group or a carboxyl group. Examples of the vinyl ester include vinyl acetate, vinyl propionate, and vinyl formate. These compounds may be used alone or in combination of two or more.

[0027] The monomer containing a sulfonic acid group is not particularly limited as long as it is copolymerizable with vinyl ester and the sulfonic acid group or its salt is present in the polyvinyl alcohol resin after saponification. Specific examples include 2-(meth)acrylamido-2-methylpropanesulfonic acid, alkali metal salts of 2-(meth)acrylamido-2-methylpropanesulfonic acid, 2-(meth)acrylamido-1-methylpropanesulfonic acid, alkali metal salts of 2-(meth)acrylamido-1-methylpropanesulfonic acid, olefinsulfonic acids such as ethylenesulfonic acid, allylsulfonic acid, and methallylsulfonic acid, and metal salts of the olefinsulfonic acids. These compounds may be used alone or in combination of two or more. In this specification, "(meth)acryl" means "acrylic and / or methacrylic".

[0028] The monomer containing a carboxyl group is not particularly limited as long as it is copolymerizable with vinyl ester and the carboxylic acid or its salt is present in the polyvinyl alcohol resin after saponification.Specific examples include maleic anhydride, monoalkyl maleic acid ester, dialkyl maleic acid ester, itaconic acid, itaconic acid alkyl ester, (meth)acrylic acid, allyl carboxylic acid, (meth)acrylic acid ester derived from the carboxylic acid or its salt after saponification, etc.These compounds may be used alone or in combination of two or more kinds.

[0029] The content of the copolymerization unit in the polyvinyl alcohol resin is not particularly limited, but may be, for example, 0.1 to 20 mol% in terms of a balance between excellent water solubility and mechanical strength. The saponification degree of the polyvinyl alcohol resin (A) is, for example, 40 mol% or more and 100 mol% or less. The viscosity average polymerization degree of the polyvinyl alcohol resin (A) is, for example, 200 or more and 10,000 or less.

[0030] Examples of the trihydric to hexahydric polyhydric alcohols that are the raw materials for the addition reaction product (B) include glycerin, trimethylolpropane, diglycerin, pentaerythritol, xylose, arabinose, ribulose, sorbitol, etc. Examples of the alkylene oxides that are the raw materials for the addition reaction product (B) include ethylene oxide, propylene oxide, etc. These compounds may be used alone or in combination of two or more.

[0031] The resin composition can be formed into a film by, for example, casting an aqueous solution of the resin composition. The resin bag 21 of the resin composition dissolves quickly in water, retains water solubility even when the electrolyte solution components 20 are enclosed therein for a long period of time, and has excellent mechanical strength.

[0032] The water-soluble resin may be a resin complex of a polyvinyl alcohol polymer and at least one polymer selected from a polysaccharide and an acrylic resin. An example of the resin bag 21 using the resin complex may be a resin laminate having a first layer containing a polyvinyl alcohol polymer and a second layer containing at least one polymer selected from a polysaccharide and an acrylic resin.

[0033] The polyvinyl alcohol polymer may be prepared by polymerizing a vinyl ester monomer and saponifying the resulting polyvinyl ester polymer. Examples of the vinyl ester monomer include vinyl formate, vinyl acetate, vinyl propionate, vinyl valerate, vinyl laurate, vinyl stearate, and vinyl benzoate. These compounds may be used alone or in combination of two or more.

[0034] The polyvinyl alcohol polymer may be a copolymer of a vinyl ester monomer and another monomer polymerizable with the vinyl ester monomer. Examples of the other monomer include olefins having 2 to 30 carbon atoms, such as ethylene, propylene, and butene; (meth)acrylic acid; (meth)acrylic acid esters, such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, ethylhexyl (meth)acrylate, dodecyl (meth)acrylate, and octadecyl (meth)acrylate; (meth)acrylamide, N-methyl (meth)acrylamide, N-ethyl (meth)acrylamide, N,N-dimethyl (meth)acrylamide, diacetone (meth)acrylamide, (meth)acrylamidopropyl dimethylamine, and ...-ethyl (meth)acrylamide, N (Meth)acrylamides such as methylol (meth)acrylamide; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, dodecyl vinyl ether, stearyl vinyl ether; vinyl cyanides such as (meth)acrylonitrile; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride; allyl compounds such as allyl acetate and allyl chloride; maleic acid; maleic acid esters; itaconic acid; itaconic acid esters; vinyl silyl compounds such as vinyltrimethoxysilane; isopropenyl acetate; N-vinylformamide, N-methyl-N Examples of the vinyl amides include N-vinylformamide, N-vinylacetamide, N-methyl-N-vinylacetamide, etc.; N-vinyl-2-pyrrolidones; N-vinyl-2-caprolactam; and sulfonic acid group-containing monomers such as 2-(meth)acrylamide-2-methylpropanesulfonic acid, 2-(meth)acrylamide-1-methylpropanesulfonic acid, ethylenesulfonic acid, allylsulfonic acid, methacrylsulfonic acid, etc. These compounds may be used alone or in combination of two or more.

[0035] The polyvinyl alcohol polymer has a degree of saponification of, for example, 75 mol% or more and 99 mol% or less. The polyvinyl alcohol polymer has a viscosity average degree of polymerization of, for example, 300 or more and 2500 or less. Examples of methods for preparing the first layer include methods using a polyvinyl alcohol polymer solution in which a polyvinyl alcohol polymer is dissolved in a solvent (for example, a casting film method, a solution coating method, a wet film method, a gel film method, etc.).

[0036] The second layer includes at least one polymer selected from the group consisting of polysaccharides and acrylic resins. Examples of the polysaccharides in the second layer include starches and cellulose resins.

[0037] Examples of starches include naturally occurring starches such as potato starch, corn starch, wheat starch, and rice starch; starches obtained by heating and gelatinizing naturally occurring starches and drying them; and processed starches such as acetylated oxidized starch, sodium starch octenyl succinate, starch acetate, oxidized starch, hydroxypropyl starch, hydroxypropylated phosphate cross-linked starch, phosphate monoesterified phosphate cross-linked starch, phosphorylated starch, and starch nitrate. Examples of cellulose-based resins include carboxymethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, and methyl cellulose. These compounds may be used alone or in combination of two or more.

[0038] An example of the acrylic resin is polyacrylamide.

[0039] Methods for preparing the second layer include, for example, methods using a polymer solution in which at least one polymer selected from polysaccharides and acrylic resins is dissolved in a solvent (for example, a casting method, a solution coating method, a wet film formation method).

[0040] Examples of methods for preparing a resin laminate having a first layer and a second layer include a method of preparing the first layer and the second layer in advance and laminating the first layer and the second layer; a method of coating a first layer prepared in advance with a coating liquid for forming a second layer containing at least one polymer selected from polysaccharides and acrylic resins; a method of coating a second layer prepared in advance with a coating liquid for forming a first layer containing a polyvinyl alcohol polymer; a method of co-extruding the first layer and the second layer; and a method of laminating the second layer by extruding or coating it onto the first layer before the first layer is completely dried or cooled during the production of the first layer, and drying or cooling the first layer and the second layer simultaneously.

[0041] Other examples of water-soluble resins include water-soluble vinyl resins such as polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, and polyvinyl methylene ether; polyether resins such as polyethylene oxide; cellulose resins such as carboxymethyl cellulose, hydroxypropyl cellulose, and hydroxyethyl cellulose; acrylic resins such as poly(meth)acrylate; and polysaccharide polymers such as alginic acid, pullulan, and xanthan.

[0042] The method of encapsulating the electrolyte solution constituents 20 in the resin bag 21 is not particularly limited, and examples thereof include a method in which the electrolyte solution constituents 20 are placed in the resin bag 21 through the opening of the resin bag 21, and then the opening of the resin bag 21 is glued or heat-sealed to encapsulate the electrolyte solution constituents 20, and a method in which the electrolyte solution constituents 20 are encapsulated using a microcapsule manufacturing method using W / O dispersion or O / W dispersion.

[0043] An example of an embodiment in which a plurality of resin bags 21, 21, 21... containing the electrolyte constituents 20 are disposed on the positive electrode 11 is an embodiment in which the resin bag 21 containing the electrolyte constituents 20 is supported on the positive electrode 11. The method for supporting the resin bag 21 containing the electrolyte constituents 20 on the positive electrode 11 is not particularly limited, and examples thereof include a method of pressing the resin bag 21 into the gap portion of the positive electrode 11, a method of dispersing the resin bag 21 in a dispersion medium such as a solvent and then impregnating the positive electrode 11 with the dispersion medium being dried and removed, a method of dividing the positive electrode 11 into a plurality of parts, arranging the resin bags 21 between the parts, and then bonding the positive electrode 11, and the like.

[0044] In addition, as an embodiment in which a plurality of resin bags 21, 21, 21... in which the electrolyte constituents 20 are enclosed are disposed on the positive electrode 11, for example, a structure in which a plurality of resin bags 21, 21, 21... are integrally formed on the positive electrode 11 can be mentioned. As an example of a structure in which a plurality of resin bags 21, 21, 21... are integrally formed on the positive electrode 11, an extrusion material of a mixture containing the material of the positive electrode 11 and the resin bag 21 in which the electrolyte constituents 20 are enclosed can be mentioned. More specifically, an extrusion material in which the material of the positive electrode 11 and the resin bag 21 in which the electrolyte constituents 20 are enclosed are kneaded to obtain a mixture containing the material of the positive electrode 11 and the resin bag 21, and the obtained mixture is extruded into a sheet shape or the like by an extruder can be mentioned. In addition, the extrusion material extruded into a sheet shape or the like may be further rolled to a predetermined thickness, as necessary.

[0045] In order to obtain a structure in which a plurality of resin bags 21, 21, 21... are integrally molded with the positive electrode 11, a binder and a dispersion medium may be further added to the material of the positive electrode 11. That is, the resin bag 21 in which the electrolyte constituents 20 are sealed may be mixed with the material of the positive electrode 11 containing the binder and the dispersion medium. Examples of the material of the positive electrode 11 include carbon such as ketjen black, acetylene black, and carbon black. Examples of the binder include polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene copolymer (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), ethylene chlorotrifluoroethylene copolymer (ECTFE), perfluoroalkoxyalkane (PFA), and perfluoroethylene propene copolymer (FEP). Examples of the dispersion medium include organic solvents such as ethylene glycol, propylene glycol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, diethylene glycol, and N-methylpyrrolidone.

[0046] Carbon, which is the material of the positive electrode 11, is a member that improves the conductivity of the positive electrode. In addition to carbon, which is the material of the positive electrode 11, the positive electrode 11 may further have a positive electrode collector and a catalyst layer. The positive electrode collector is a member that has conductivity for transmitting electrons emitted from the negative electrode 12 to the electric wire portion and air permeability for transmitting oxygen. Examples of the positive electrode collector include wire mesh, foam metal, expanded metal, metal cloth, punching metal, and porous metal. The catalyst layer functions as a reaction portion of the positive electrode 11. Examples of a method for manufacturing the positive electrode 11 using an extrusion material of a mixture of the material of the positive electrode 11 and the resin bag 21 include a method of stacking the extrusion material and the catalyst layer on the positive electrode collector and pressing them together. Examples of a method for manufacturing the positive electrode 11 include a method of extruding a mixture of the material of the positive electrode 11, the resin bag 21, and the catalyst into a sheet shape or the like to obtain an extrusion material, and stacking the extrusion material on the positive electrode collector and pressing it together.

[0047] Examples of the electrolyte constituent 20 enclosed in the resin bag 21, the resin type of which is a water-soluble resin, include alkali metal salts, such as salts of alkali metals and halogens, such as sodium chloride and potassium chloride, or aqueous solutions of the alkali metal salts. Another electrolyte constituent 20 includes water. Even if water, an alkali metal salt, or an aqueous solution of an alkali metal salt is stored inside the resin bag 21, which is a water-soluble resin, salting out occurs inside the resin bag 21, so that the resin bag 21 does not dissolve and functions as a shell.

[0048] Examples of the active material of the negative electrode 12 include magnesium (Mg), magnesium alloys, aluminum (Al), aluminum alloys, lithium (Li), lithium alloys, calcium (Ca), calcium alloys, zinc (Zn), zinc alloys, etc. Among these, magnesium (Mg) and magnesium alloys are preferred from the viewpoints of power generation efficiency and availability.

[0049] The separator 13 is formed of a material having electrical insulation, ion permeability, and liquid permeability. Examples of materials for forming the separator 13 include resins such as polyethylene, polypropylene, polyethylene terephthalate, cellulose, polyamide, and acrylic resin, and glass. The separator 13 is a member having voids, and examples of such materials include nonwoven fabric, glass fiber, woven fabric having a mesh structure, and membrane members having independent pores and connecting pores. Examples of materials having voids that constitute the separator 13 include members having a porous structure.

[0050] Next, a power generation system of the metal-air battery 10 will be described when water, which is the detection target of the liquid detection sensor 1, comes into contact with the metal-air battery 10. For ease of explanation, a case will be described in which magnesium (Mg) is used as the negative electrode 12. When water comes into contact with the peripheral portion 14 of the separator 13 and permeates the entire separator 13, an oxidation reaction shown in (1) below occurs in the negative electrode 12. Also, a reduction reaction shown in (2) below occurs in the positive electrode 11. From the above, the reaction shown in (3) below occurs in the metal-air battery 10 as a whole, and the metal-air battery 10 discharges, i.e., generates power by itself. (1) 2Mg → 2Mg 2+ +4e - (2)O2+2H2O+4e - →4OH - (3) 2Mg + O2 + 2H2O → 2Mg(OH)2

[0051] Next, an example of the detection operation of the liquid detection sensor 1 when the liquid detection sensor 1 detects water as a detection target will be described. As shown in FIG. 2, when the water 110 as a detection target comes into contact with the metal-air battery 10 of the liquid detection sensor 1, it permeates the entire separator 13, and then permeates the entire positive electrode 11. As the water 110 as a detection target permeates the entire positive electrode 11, the resin bag 21 formed of a resin having solubility or dispersibility in the water 110 dissolves or disperses. That is, the resin bag 21 is destroyed by the water 110 as a detection target. When the resin bag 21 dissolves or disperses, the electrolyte constituents 20 (e.g., sodium chloride, water containing sodium chloride) sealed in the resin bag 21 are released into the water 110. Also, as described above, when the water 110 as a detection target permeates the separator 13, the water 110 acts as an electrolyte, and the metal-air battery 10 is discharged. When the metal-air battery 10 is discharged, the water 110 acting as the electrolyte contains the electrolyte constituents 20 released from the resin bag 21, and the electrolyte constituents 20 act to improve the ionic conductivity between the positive electrode 11 and the negative electrode 12, thereby improving the power generation performance of the metal-air battery 10.

[0052] When the metal-air battery 10 generates power, the power from the metal-air battery 10 is supplied to the notification unit 100 through the electric wire unit 101. When the notification unit 100 receives the power generated from the metal-air battery 10, it notifies the detection of liquid by a notification means provided in the notification unit 100.

[0053] In the liquid detection sensor 1, the electrolyte constituent 20 of the metal-air battery 10, which is the power source, is sealed inside the resin bag 21 that is soluble or dispersible in the water 110 to be detected, and therefore the liquid detection sensor 1 can be used in any field for detecting water, improving versatility. In addition, in the liquid detection sensor 1, the electrolyte constituent 20 of the metal-air battery 10 is sealed inside the resin bag 21, and therefore the metal-air battery 10 can be prevented from being deteriorated by the electrolyte constituent 20 even if the liquid detection sensor 1 is installed for a long period of time, improving detection accuracy. In addition, in the liquid detection sensor 1, the electrolyte constituent 20 of the metal-air battery 10 is sealed inside the resin bag 21, and therefore the electrolyte constituent 20 that imparts excellent power generation performance to the metal-air battery 10 while preventing deterioration of the metal-air battery 10 can be used, and therefore the metal-air battery 10 can exhibit excellent power generation performance. Furthermore, in the liquid detection sensor 1, the metal-air battery 10 exhibits excellent power generation performance, so that an alarm can be reliably transmitted to a location far from the site of leakage or flooding, improving versatility. Also, in the liquid detection sensor 1, the metal-air battery 10 exhibits excellent power generation performance, so that the amount of power received by the notification unit 100 increases, improving the notification performance of the notification unit 100.

[0054] In addition, in the liquid detection sensor 1, since the resin of the resin bag 21 is a water-soluble resin, the detection target, water, can be detected more reliably, and since there are multiple resin bags 21 in which the electrolyte constituents 20 are sealed, the electrolyte constituents 20 are smoothly supplied to the entire positive electrode 11, thereby improving the power generation efficiency of the metal-air battery 10.

[0055] Next, a liquid detection sensor according to a second embodiment of the present invention will be described. Note that the liquid detection sensor according to the second embodiment has major components in common with the liquid detection sensor according to the first embodiment, and therefore the same components as those in the liquid detection sensor according to the first embodiment will be described using the same reference numerals. Note that Fig. 3 is a side view illustrating the outline of the liquid detection sensor according to the second embodiment of the present invention, and Fig. 4 is a side view illustrating the state of the liquid detection sensor according to the second embodiment of the present invention when detecting liquid.

[0056] The liquid detection sensor according to the first embodiment is a water detection sensor in which the resin bag is made of a resin that is soluble or dispersible in water. Instead, the liquid detection sensor 2 according to the second embodiment is an oil detection sensor in which an electrolyte component 30 is sealed inside a resin bag 31, and the resin bag 31 in which the electrolyte component 30 is sealed is made of a resin that is soluble or dispersible in oil.

[0057] In this way, the liquid detection sensor of the present invention can appropriately change the type of liquid to be detected by appropriately changing the solubility or dispersibility characteristics of the resin that forms the resin bag. In other words, the liquid detection sensor of the present invention is highly versatile in that the type of liquid to be detected can be easily changed.

[0058] As shown in Fig. 3, in the metal-air battery 10, an electrolyte component 30 is disposed in a positive electrode 11. There are a plurality of resin bags 31 in which the electrolyte component 30 is enclosed, and the electrolyte component 30 is divided into a plurality of parts at a fixed amount and enclosed inside each of the resin bags 31. The resin bags 31 in which the electrolyte component 30 is enclosed are dispersed and disposed on the surface and inside of the positive electrode 11 over the entire positive electrode 11. In the liquid detection sensor 2 in Fig. 3, a plurality of resin bags 31, 31, 31... in which the electrolyte component 30 is enclosed are disposed over the entire positive electrode 11.

[0059] The resin bag 31 is made of, for example, an oil-soluble resin, which is a resin that is soluble or dispersible in oil. By making the resin bag 31 out of an oil-soluble resin, the liquid detection sensor 2 functions as an oil detection sensor.

[0060] Examples of oil-soluble resins include terpene resins such as candelilla resin, hydrogenated pentaerythrityl rosinate, and hydrogenated glyceryl abietate, silicone resins such as trimethylsiloxysilicate, polymethylsilsesquioxane, and acrylic-silicone graft copolymer, and hydrocarbon resins such as polyvinyl isobutyl ether and polyisobutylene, etc. These compounds may be used alone or in combination of two or more.

[0061] The method of encapsulating the electrolyte constituents 30 in the resin bag 31 is not particularly limited, and examples thereof include a method in which, as in the liquid detection sensor of the first embodiment, the electrolyte constituents 30 are placed in the resin bag 31 through the opening of the resin bag 31, and then the opening of the resin bag 31 is glued or heat-sealed to encapsulate the electrolyte constituents 30, or a method in which the electrolyte constituents 30 are encapsulated using a microcapsule manufacturing method using W / O dispersion or O / W dispersion.

[0062] An example of an embodiment in which a plurality of resin bags 31, 31, 31, ..., in which the electrolyte constituents 30 are enclosed, are arranged on the positive electrode 11 is, for example, an embodiment in which the resin bag 31 in which the electrolyte constituents 30 are enclosed is supported on the positive electrode 11, as in the liquid detection sensor according to the first embodiment. The method of supporting the resin bag 31 in which the electrolyte constituents 30 are enclosed on the positive electrode 11 is not particularly limited, and examples thereof include, as in the liquid detection sensor according to the first embodiment, a method in which the resin bag 31 is pressed into the gap portion of the positive electrode 11, a method in which the resin bag 31 is dispersed in a dispersion medium such as a solvent and then impregnated into the positive electrode 11 to dry and remove the dispersion medium, a method in which the positive electrode 11 is divided into a plurality of parts, the resin bag 31 is arranged between the parts, and then the positive electrode 11 is bonded, and the like.

[0063] In addition, as an embodiment in which a plurality of resin bags 31, 31, 31... in which the electrolyte constituents 30 are enclosed are disposed on the positive electrode 11, there may be mentioned, for example, a structure in which a plurality of resin bags 31, 31, 31... are integrally formed on the positive electrode 11, as in the liquid detection sensor according to the first embodiment. As an example of a structure in which a plurality of resin bags 31, 31, 31... are integrally formed on the positive electrode 11, there may be mentioned, for example, an extrusion material of a mixture of the material of the positive electrode 11 and the resin bag 31 in which the electrolyte constituents 30 are enclosed, as in the liquid detection sensor according to the first embodiment. More specifically, there may be mentioned an extrusion material in which the material of the positive electrode 11 and the resin bag 31 in which the electrolyte constituents 30 are enclosed are kneaded to obtain a mixture of the material of the positive electrode 11 and the resin bag 31, and the obtained mixture is extruded into a sheet shape or the like by an extruder. In addition, the extrusion material extruded into a sheet shape or the like may be further rolled to a predetermined thickness, as necessary.

[0064] The oil that is the detection target of the liquid detection sensor 2 is not a constituent of the electrolyte solution of the metal-air battery 10. Therefore, the resin bag 31, whose resin type is an oil-soluble resin, contains an electrolyte solution as the electrolyte solution constituent 30. Examples of the electrolyte solution constituent 30 include water containing an alkali metal salt such as sodium chloride or potassium chloride (aqueous solution of an alkali metal salt), or water.

[0065] Next, an example of the detection operation of the liquid detection sensor 2 when the liquid detection sensor 2 detects oil as a detection target will be described. As shown in FIG. 4, when the oil 120 as a detection target comes into contact with the metal-air battery 10 of the liquid detection sensor 2, it permeates the entire separator 13, and then permeates the entire positive electrode 11. As the oil 120 permeates the entire positive electrode 11, the resin bag 31 formed of a resin having solubility or dispersibility in the oil 120 dissolves or disperses. That is, the resin bag 31 is destroyed by the oil 120 as a detection target. When the resin bag 31 dissolves or disperses, the electrolyte constituent 30 (e.g., an aqueous solution of an alkali metal salt) enclosed in the resin bag 31 is released into the oil 120. The electrolyte constituent 30 released into the oil 120 acts as an electrolyte, so that the metal-air battery 10 discharges. When the metal-air battery 10 discharges, an electrolyte such as an aqueous solution of an alkali metal salt is released from the resin bag 31, and the electrolyte constituents 30 act to improve the ionic conductivity between the positive electrode 11 and the negative electrode 12, thereby improving the power generation performance of the metal-air battery 10.

[0066] In the liquid detection sensor 2, the electrolyte constituent 30 of the metal-air battery 10, which is the power source, is sealed inside a resin bag 31 that is soluble or dispersible in the oil 120, which is the detection target, and therefore the oil, which is the detection target, can be detected more reliably. Also, in the liquid detection sensor 2, the electrolyte constituent 30 of the metal-air battery 10 is sealed inside the resin bag 31, and therefore the metal-air battery 10 can be prevented from being deteriorated by the electrolyte constituent 30 even if the liquid detection sensor 2 is installed for a long period of time, and the detection accuracy is improved.

[0067] Next, an example of a method of using the liquid detection sensor of the present invention will be described. For convenience of explanation, the example of a method of using the liquid detection sensor will be described using the liquid detection sensor 1 according to the first embodiment of the present invention. Note that FIG. 5 is an explanatory diagram of the example of a method of using the liquid detection sensor of the present invention.

[0068] As shown in FIG. 5, a transmitter that operates a transmission function to a receiver 200 when it receives power generated from the metal-air battery 10 is used as the alarm unit 100 connected to the metal-air battery 10 via an electric wire unit 101. When the metal-air battery 10 detects a liquid to be detected (water 110 in FIG. 5) and generates power, the alarm unit 100 operates a transmission function by receiving power from the metal-air battery 10 and transmits a detection signal to the receiver 200. Examples of the transmitter include a wireless transmitter and a wired transmitter. In FIG. 5, a wireless transmitter is used as the alarm unit 100, and the alarm unit 100 can wirelessly transmit a detection signal to the receiver 200. For wireless communication, an existing wireless method such as wireless LAN, Bluetooth (registered trademark), or Wi-Fi can be used.

[0069] When the receiving unit 200 receives a detection signal from the alarm unit 100 of the liquid detection sensor 1, it detects that a leak or the like has occurred in the liquid being detected (in Figure 5, a water leak or flooding), notifies a person of the occurrence of the water leak or flooding, and automatically stops the device, etc., if necessary.

[0070] Next, a liquid detection sensor according to another embodiment of the present invention will be described. In the liquid detection sensor according to the first and second embodiments described above, a plurality of resin bags containing electrolyte constituents are distributed over the entire positive electrode and arranged on the surface and inside of the separator, but instead, one resin bag may be provided. In this case, the electrolyte constituents are sealed in the resin bag in a combined state.

[0071] In the liquid detection sensor according to the first embodiment, the resin bag is made of a water-soluble resin, and in the liquid detection sensor according to the second embodiment, the resin bag is made of an oil-soluble resin. Alternatively, in one metal-air battery, a resin bag made of a water-soluble resin and a resin bag made of an oil-soluble resin may be used together. By using a resin bag made of a water-soluble resin and a resin bag made of an oil-soluble resin together, one liquid detection sensor can detect both water and oil. In addition, in the liquid detection sensor according to the first and second embodiments, a separator is provided between the positive electrode and the negative electrode. However, if a short circuit caused by contact between the positive electrode and the negative electrode can be prevented, a separator is not necessary. Also, a support member that supports the positive electrode and the negative electrode at a predetermined interval may be used instead of a separator.

[0072] In the above-mentioned example of the method of using the liquid detection sensor, the notification unit is a transmitter having a function of transmitting to the receiver, but instead of this, it may be a liquid detection display unit that receives power from the metal-air battery and notifies a person of the detection of liquid. Examples of the display means of the liquid detection display unit include turning on a warning light and emitting a warning sound. [Industrial Applicability]

[0073] The liquid detection sensor of the present invention is versatile and can prevent deterioration of the metal-air battery, which is the power source, even when installed for a long period of time, and the metal-air battery, which is the power source, can exhibit excellent power generation performance, so it can be used in a wide range of liquid detection fields, such as detecting water and rain leaks in buildings, detecting water and oil leaks in various facilities and factories, detecting flooding of roads and underground facilities, detecting dangerous water levels by detecting the water level of rivers, lakes, etc., detecting blood and drug leaks in medical settings, and detecting urination in nursing care settings. [Explanation of symbols]

[0074] 1, 2 Liquid detection sensor 10 Metal-air battery 11 Positive electrode 12 Negative electrode 13 Separator 20, 30 Electrolyte components 21, 31 Resin bag body 100 Notification Department

Claims

1. A metal-air battery having a positive electrode, a negative electrode, and an electrolyte component disposed on the positive electrode, The electrolyte solution components are sealed inside a resin bag, and the resin of the resin bag has solubility or dispersibility in a liquid to be detected, A liquid detection sensor in which at least a portion of the resin bag in which the electrolyte constituent components are sealed is disposed inside the positive electrode.

2. 2. The liquid detection sensor according to claim 1, wherein the resin of the resin bag is a water-soluble resin or an oil-soluble resin.

3. 3. The liquid detection sensor according to claim 1, wherein the number of the resin bags in which the electrolyte constituents are sealed is one or more.

4. 4. The liquid detection sensor according to claim 1, wherein the resin bag in which the electrolyte constituents are sealed is supported by the positive electrode.

5. 5. The liquid detection sensor according to claim 1, wherein the resin bag in which the components of the electrolyte are sealed is integrally formed with the positive electrode.

6. 6. The liquid detection sensor according to claim 1, further comprising an extrusion material of a mixture of the positive electrode material and the resin bag in which components of the electrolyte are sealed.

7. 7. The liquid detection sensor according to claim 1, wherein the electrolyte component comprises water, an alkali metal salt, or an aqueous solution of an alkali metal salt.

8. 8. The liquid detection sensor according to claim 1, wherein the active material of the negative electrode contains at least one metal selected from the group consisting of magnesium (Mg), aluminum (Al), lithium (Li), calcium (Ca), and zinc (Zn).

9. The liquid detection sensor according to claim 1 , further comprising an alarm unit that receives power from the metal-air battery and notifies the detection of liquid.

10. The liquid detection sensor according to claim 1 , further comprising an alarm unit capable of wirelessly transmitting a detection signal from the metal-air battery to a receiver unit.

11. The liquid detection sensor according to any one of claims 1 to 10, which is a water detection sensor.

12. The liquid detection sensor according to any one of claims 1 to 10, which is an oil detection sensor.

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