Liquid detection sensor

Abstract

To provide a liquid detection sensor which has general-purpose properties, which can prevent a deterioration in a metal-air battery serving as a power source, even when installed for a long period of time, and which enables excellent power generation performance to be exerted by the metal-air battery serving as the power source.SOLUTION: A liquid detection sensor 1 comprises a metal-air battery 10 that has a positive electrode 11, a negative electrode 12 having a first region 41 facing the positive electrode, and an electrolyte component 20 arranged in the state of facing a second region 42 of the negative electrode different from the first region. The electrolyte component is encapsulated into a resin bag body 21. A resin of the resin bag body has dissolubility or dispersibility for a liquid to be detected.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 that has excellent power generation performance and excellent long-term storage properties. [Background technology]

[0002] Liquid detection sensors are sometimes used to detect leaks and flooding in buildings, underground facilities, factories, medical facilities, etc. Liquid detection sensors are placed in locations where leaks and flooding must be prevented. Liquid detection sensors detect leaks by detecting electrical changes that occur when external liquid comes into contact with the battery contained in the liquid detection sensor.

[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 the liquid detection sensor of 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 dispersed into the absorbent member comes into contact with 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 the liquid detection sensor of 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 power from the magnesium battery, a receiver that receives the detection signal transmitted from the transmitter, and a receiver terminal that has alarm means for issuing an alarm about 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 power using blood or injection fluid leaked from the syringe needle as the electrolyte.

[0005] Liquid detection sensors need to detect liquid leaks 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 specifically proposed for use in detecting liquids other than blood in medical settings, and therefore lack versatility.

[0006] On the other hand, detection of liquid leaks 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 sites, etc., and liquid detection sensors are required to have versatility to detect water, oil, etc. However, as described above, the liquid detection sensors of Patent Documents 1 and 2 have a problem in that they lack versatility.

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

[0008] When a metal-air battery is used as the power source for the 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 the electrolyte. For example, if an alkali metal salt is impregnated in advance in a separator provided between the positive and negative electrodes of the metal-air battery, when the separator containing the alkali metal salt comes into contact with water, which is the liquid to be detected, the action of the water containing the alkali metal salt improves the ionic conductivity between the positive and negative electrodes, allowing the metal-air battery to exhibit excellent power generation performance.

[0009] However, if a liquid detection sensor is installed for a long period of time while the separator contains alkali metal salt, the alkali metal salt in the separator may absorb moisture and liquefy, causing deterioration of the metal-air battery's negative electrode.If the negative electrode of the metal-air battery deteriorates while the liquid detection sensor is installed for a long period of time, it will be unable to accurately detect liquid leakage or flooding, and the metal-air battery will not be able to demonstrate excellent power generation performance. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] International Publication No. 2012 / 020507 [Patent Document 2] Japanese Patent Application Publication No. 2017-148332 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 serves as the power source even when installed for a long period of time, and allows the metal-air battery that serves as the 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 including a positive electrode, a negative electrode having a first portion facing the positive electrode, and an electrolyte component disposed opposite a second portion of the negative electrode different from the first portion, The liquid detection sensor has the electrolyte constituent components sealed inside a resin bag, and the resin of the resin bag has solubility or dispersibility in the liquid to be detected. [2] A liquid detection sensor as described in [1], wherein the second portion of the resin bag in which the electrolyte constituents are sealed is arranged opposite to the first portion and has an area opposite to the first portion. [3] A liquid detection sensor according to [1] or [2], further comprising a support member between the positive electrode and the first portion, which supports the positive electrode and the first portion at a predetermined distance, and the support member having an extension portion extending from the first portion to the position of the resin bag opposite the second portion in which the components of the electrolyte solution are sealed. [4] The liquid detection sensor according to [3], wherein the extension portion of the support member is disposed between the resin bag in which the electrolyte constituent components are sealed and the second portion. [5] The liquid detection sensor according to [3], wherein the resin bag containing the electrolyte constituents is disposed between the extension portion of the support member and the second portion. [6] The liquid detection sensor according to any one of [1] to [5], wherein the resin of the resin bag is a water-soluble resin or an oil-soluble resin. [7] The liquid detection sensor according to any one of [1] to [6], wherein the resin bag in which the electrolyte constituents are sealed is one or more. [8] The liquid detection sensor according to any one of [1] to [7], wherein the electrolyte component includes 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], which has an alarm unit that receives power from the metal-air battery and notifies of liquid detection.

[11] The liquid detection sensor according to any one of [1] to [9], which has an alarm unit capable of wirelessly transmitting a detection signal from the metal-air battery to a receiver 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 components of the electrolyte sealed inside the resin bag to be released to the negative electrode of the metal-air battery and between the positive and negative electrodes. The release of the components of the electrolyte to the negative electrode of the metal-air battery and between the positive and negative electrodes 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. [Effects of the Invention]

[0014] According to an embodiment of the liquid detection sensor of the present invention, the electrolyte components of a metal-air battery, which serves as a power source, are sealed inside a resin bag that is soluble or dispersible in the liquid to be detected. By appropriately selecting the type of resin for the resin bag, the versatility of the detection target, such as detecting water or oil, is improved. Furthermore, according to an embodiment of the liquid detection sensor of the present invention, the electrolyte components of the metal-air battery are sealed inside a resin bag, thereby preventing the metal-air battery from deteriorating due to the electrolyte components, even if the liquid detection sensor is installed for a long period of time. Furthermore, according to an embodiment of the liquid detection sensor of the present invention, the electrolyte components of the metal-air battery are sealed inside a resin bag, thereby preventing the metal-air battery from deteriorating while using electrolyte components that impart excellent power generation performance to the metal-air battery. This allows the metal-air battery to exhibit excellent power generation performance and reliably transmit an alarm to a location far from the site of a liquid leak or flooding. Therefore, the liquid detection sensor of the present invention can reliably transmit an alarm to a location far from the site of a liquid leak or flooding, thereby improving convenience and versatility.

[0015] According to an aspect of the liquid detection sensor of the present invention, a resin bag containing electrolyte constituent components is arranged opposite a second portion of the negative electrode that is different from a first portion of the negative electrode that faces the positive electrode. Therefore, even if the resin bag is damaged by the influence of humidity or moisture in the atmosphere, corrosion of components that constitute the metal-air battery, such as the positive electrode and negative electrode, caused by leakage of the electrolyte constituent components can be prevented.

[0016] Furthermore, according to an embodiment of the liquid detection sensor of the present invention, the second portion of the negative electrode, which is arranged opposite the resin bag containing the electrolyte constituent components, has an area facing the first portion of the negative electrode facing the positive electrode. Therefore, even if the resin bag is damaged, corrosion of the components constituting the metal-air battery, such as the positive electrode and negative electrode, due to leakage of the electrolyte constituent components can be more reliably prevented.

[0017] 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 the resin of the resin bag body is an oil-soluble resin, so that it functions as an oil detection sensor that can more reliably detect the target, oil.

[0018] According to an aspect of the liquid detection sensor of the present invention, since there are multiple resin bags in which the electrolyte constituent components are sealed, the electrolyte constituent components are smoothly supplied to the entire metal-air battery, thereby further improving the power generation efficiency of the metal-air battery. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a side view illustrating an outline of a liquid detection sensor according to a first embodiment of the present invention. [Figure 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 a liquid. [Figure 3] FIG. 6 is a side view illustrating an outline of a liquid detection sensor according to a second embodiment of the present invention. [Figure 4] FIG. 10 is a side view illustrating a state when a liquid is detected by a liquid detection sensor according to a second embodiment of the present invention. [Figure 5] FIG. 10 is a side view illustrating an outline of a liquid detection sensor according to a third embodiment of the present invention. [Figure 6] FIG. 10 is a side view illustrating a state when a liquid is detected by a liquid detection sensor according to a third embodiment of the present invention. [Figure 7] FIG. 10 is a side view illustrating an outline of a liquid detection sensor according to a fourth embodiment of the present invention. [Figure 8] FIG. 10 is a side view illustrating a state when a liquid is detected by a liquid detection sensor according to a fourth embodiment of the present invention. [Figure 9] 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 INVENTION

[0020] Liquid detection sensors according to embodiments of the present invention will be described in detail with reference to the drawings. First, a liquid detection sensor according to a first embodiment of the present invention will be described. FIG. 1 is a side view illustrating an overview of the liquid detection sensor according to the first embodiment of the present invention, and FIG. 2 is a side view illustrating the state of the liquid detection sensor according to the first embodiment of the present invention when detecting liquid.

[0021] As shown in Fig. 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.

[0022] The metal-air battery 10 includes a positive electrode 11, a negative electrode 12 facing the positive electrode 11, and a support member 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 support member 13, and the negative electrode 12 are all sheet-shaped and have a laminate structure in which the positive electrode 11, the support member 13, and the negative electrode 12 are stacked in this order. The negative electrode 12 has a first region 41 facing the positive electrode 11 and a second region 42 different from the first region 41. In the metal-air battery 10, the second region 42 is an area facing the first region 41, with the first region 41 being the front surface of the negative electrode 12 and the second region 42 being the back surface of the negative electrode 12. Therefore, the second portion 42 faces the positive electrode 11 via the first portion 41, and in terms of its positional relationship with the positive electrode 11, the second portion 42 is located farther away from the positive electrode 11 than the first portion 41.

[0023] The support member 13 is provided between the positive electrode 11 and the first portion 41 of the negative electrode 12, and supports the positive electrode 11 and the negative electrode 12 with a predetermined distance between the first portion 41 of the positive electrode 11 and the negative electrode 12. The peripheral portion 14 of the support member 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 support member 13 acts as a separator and has the function of supporting the positive electrode 11 and the negative electrode 12 with a predetermined distance between them to prevent short circuits due to contact between the positive electrode 11 and the negative electrode 12. The support member 13 also has an extension portion 15 that extends to cover the second portion 42 of the negative electrode 12. Therefore, the negative electrode 12 and the extension portion 15 of the support member 13 form a laminated structure on the side of the second portion 42 of the negative electrode 12.

[0024] In the metal-air battery 10 of the liquid detection sensor 1, the electrolyte component 20 is disposed opposite the second portion 42 of the negative electrode 12. That is, the electrolyte component 20 is disposed independently of the positive electrode 11, the negative electrode 12, and the support member 13. In the metal-air battery 10 of the liquid detection sensor 1, the extension portion 15 of the support member 13 is disposed between the electrolyte component 20 and the second portion 42. The electrolyte component 20 is a component that constitutes the electrolyte of the metal-air battery 10, or 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.

[0025] As shown in FIG. 1 , the electrolyte solution constituents 20 are sealed inside a resin bag 21. Therefore, the electrolyte solution constituents 20 are not in contact with any of the positive electrode 11, the support member 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 encapsulates the electrolyte solution constituents 20 and seals and packages a certain amount of the electrolyte solution constituents 20. Therefore, the resin bag 21 functions as a shell.

[0026] As described above, in the negative electrode 12, the second region 42 faces the first region 41, and the resin bag 21 in which the electrolyte solution constituents 20 are sealed is disposed opposite the second region 42 of the negative electrode 12. The extending portion 15 of the support member 13 extends from the first region 41 to the position of the resin bag 21 in which the electrolyte solution constituents 20 are sealed, disposed opposite the second region 42. The extending portion 15 of the support member 13 is disposed between the resin bag 21 in which the electrolyte solution constituents 20 are sealed and the second region 42. Therefore, the resin bag 21 in which the electrolyte solution constituents 20 are sealed faces the second region 42 of the negative electrode 12 via the extending portion 15 of the support member 13.

[0027] In the metal-air battery 10 of the liquid detection sensor 1, there are a plurality of resin bags 21 in which electrolyte constituent components 20 are sealed, and the electrolyte constituent components 20 are divided into a plurality of portions, each containing a fixed amount, and sealed inside each of the resin bags 21. A support 22 is disposed opposite the second portion 42 of the negative electrode 12, and the plurality of resin bags 21, 21, 21... in which the electrolyte constituent components 20 are sealed are held by the support 22. The support 22 is a separate member from the positive electrode 11, the negative electrode 12, and the support member 13, and is also a separate member from the positive electrode 11, the negative electrode 12, and the support member 13. The support 22 can be, for example, a porous member.

[0028] The resin bag 21 containing the electrolyte solution components 20 is held by the support 22, which is disposed opposite the second region 42 of the negative electrode 12. This means that the resin bag 21 containing the electrolyte solution components 20 is disposed independently of the positive electrode 11, the negative electrode 12, and the support member 13. The resin bag 21 containing the electrolyte solution components 20 is held by the support 22, which is disposed opposite the second region 42 of the negative electrode 12. This means that the resin bag 21 containing the electrolyte solution components 20 is located farther from the positive electrode 11 than the first region 41 of the negative electrode 12, which faces the positive electrode 11. Therefore, the extension 15 of the support member 13 is disposed between the support 22, which holds the resin bag 21 containing the electrolyte solution components 20, and the second region 42. The support 22 faces the second region 42 of the negative electrode 12 via the extension 15 of the support member 13.

[0029] The support 22 is provided so as to overlap substantially the entire negative electrode 12 in a plan view, i.e., when viewed from the stacking direction of the positive electrode 11, the support member 13, and the negative electrode 12. Resin bags 21 in which electrolyte solution constituent components 20 are sealed are disposed in a dispersed state on the surface and inside of the support 22. In the liquid detection sensor 1, a plurality of resin bags 21, 21, 21 in which electrolyte solution constituent components 20 are sealed are disposed over the entire support 22. The plurality of resin bags 21, 21, 21 in which electrolyte solution constituent components 20 are sealed are disposed so as to overlap substantially the entire negative electrode 12 in a plan view.

[0030] The resin bag 21 is made of a resin that is soluble or dispersible in the liquid that is the detection target of the liquid detection sensor 1. When the liquid that is the detection target of the liquid detection sensor 1 is water or a liquid that contains water, the resin bag 21 is made of, for example, a water-soluble resin. Since the resin bag 21 is made of a water-soluble resin, it has solubility or dispersibility in water, and the liquid detection sensor 1 functions as a water detection sensor.

[0031] 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 with 1 mole of a trihydric to hexahydric polyhydric alcohol.

[0032] The polyvinyl alcohol resin (A) is a saponified polyvinyl ester containing copolymer units consisting of sulfonic acid groups or carboxyl groups. Examples of vinyl esters include vinyl acetate, vinyl propionate, and vinyl formate. These compounds may be used alone or in combination of two or more.

[0033] The sulfonic acid group-containing monomer 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, olefin sulfonic acids such as ethylene sulfonic acid, allyl sulfonic acid, and methallyl sulfonic acid, and metal salts of the olefin sulfonic acids. These compounds may be used alone or in combination. In this specification, "(meth)acrylic" means "acrylic and / or methacrylic."

[0034] The carboxyl group-containing monomer 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 ester, dialkyl maleic ester, itaconic acid, itaconic acid alkyl ester, (meth)acrylic acid, allylcarboxylic acid, and (meth)acrylic ester derived from the carboxylic acid or its salt after saponification. These compounds may be used alone or in combination of two or more.

[0035] The content of the copolymerization unit in the polyvinyl alcohol resin (A) is not particularly limited, but may be, for example, 0.1 to 20 mol % in order to achieve a good balance between 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.

[0036] Examples of the tri- to hexahydric polyhydric alcohols that are 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 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.

[0037] The resin composition can be used to form 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.

[0038] Furthermore, examples of the water-soluble resin include a resin composite of a polyvinyl alcohol polymer and at least one polymer selected from polysaccharides and acrylic resins. Examples of the resin bag 21 using the resin composite include a resin laminate having a first layer containing a polyvinyl alcohol polymer and a second layer containing at least one polymer selected from polysaccharides and acrylic resins.

[0039] Examples of polyvinyl alcohol polymers include polymers prepared by polymerizing vinyl ester monomers and saponifying the resulting polyvinyl ester polymers. Examples of vinyl ester monomers 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.

[0040] 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 polymerizable with the vinyl ester 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, and (meth)acrylamidopropyl diacrylate. (Meth)acrylamides such as methylamine and N-methylol (meth)acrylamide; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, dodecyl vinyl ether, and stearyl vinyl ether; vinyl cyanides such as (meth)acrylonitrile; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl fluoride, and vinylidene fluoride; allyl compounds such as allyl acetate and allyl chloride; maleic acid; maleic acid esters; itaconic acid; itaconic acid esters; vinylsilyl compounds such as vinyltrimethoxysilane; isopropenyl acetate; N-vinylformamide, N-methyl-N Examples of the vinyl amides include N-vinylformamide, N-vinylacetamide, and N-methyl-N-vinylacetamide; N-vinyl-2-pyrrolidones; N-vinyl-2-caprolactam; and sulfonic acid group-containing monomers such as 2-(meth)acrylamido-2-methylpropanesulfonic acid, 2-(meth)acrylamido-1-methylpropanesulfonic acid, ethylenesulfonic acid, allylsulfonic acid, and methacrylic acid. These compounds may be used alone or in combination of two or more.

[0041] 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 of the resin bag 21 include methods using a polyvinyl alcohol polymer solution in which a polyvinyl alcohol polymer is dissolved in a solvent (e.g., a casting film method, a solution coating method, a wet film method, a gel film method, etc.).

[0042] The second layer of the resin bag 21 contains at least one resin selected from polysaccharides and (meth)acrylic resins. Examples of the polysaccharides in the second layer include starches and cellulose-based resins.

[0043] 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 octenyl succinate starch, starch acetate, oxidized starch, hydroxypropyl starch, hydroxypropylated phosphate cross-linked starch, phosphate monoesterified phosphate cross-linked starch, phosphated starch, and starch nitrate. These compounds may be used alone or in combination of two or more. 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.

[0044] An example of the (meth)acrylic resin is poly(meth)acrylamide.

[0045] Methods for preparing the second layer of the resin bag body 21 include, for example, methods using a resin solution in which at least one resin selected from polysaccharides and (meth)acrylic resins is dissolved in a solvent (e.g., a casting film method, a solution coating method, a wet film method).

[0046] Methods for preparing the resin bag body 21, which is a resin laminate having a first layer and a second layer, include, for example, a method in which the first layer and the second layer are prepared in advance and then laminated together; a method in which a coating liquid for forming a second layer containing at least one resin selected from polysaccharides and (meth)acrylic resins is coated onto a first layer that has been prepared in advance with a coating liquid for forming a first layer containing a polyvinyl alcohol polymer onto a second layer that has been prepared in advance; a method in which the first layer and the second layer are co-extruded; and a method in which, when producing the first layer, the second layer is extruded or coated onto the first layer and laminated before the first layer is completely dried or cooled, and then the first layer and the second layer are dried or cooled simultaneously.

[0047] Examples of water-soluble resins other than those mentioned above include water-soluble vinyl resins such as polyvinyl alcohol, polyvinylpyrrolidone, poly(meth)acrylamide, and polyvinyl methylene ether; polyether resins such as polyethylene oxide; cellulose resins such as carboxymethyl cellulose, hydroxypropyl cellulose, and hydroxyethyl cellulose; (meth)acrylic resins such as poly(meth)acrylate; and polysaccharide polymers such as alginic acid, pullulan, and xanthan.

[0048] The method for 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 a microcapsule manufacturing method using W / O dispersion or O / W dispersion is used to encapsulate the electrolyte solution constituents 20. The method for holding a plurality of resin bags 21 encapsulating the electrolyte solution constituents 20 on the support 22 is also not particularly limited, and examples thereof include a method in which the resin bags 21 are pressed into voids in the support 22, a method in which the resin bags 21 are dispersed in a dispersion medium such as a solvent and then impregnated into the support 22 to dry and remove the dispersion medium, and a method in which the support 22 is divided into a plurality of pieces, the resin bags 21 are arranged between the pieces, and then the support 22 is glued together.

[0049] Examples of the electrolyte constituent 20 enclosed in the resin bag 21 made of a water-soluble resin include alkali metal salts such as salts of alkali metals and halogens, such as sodium chloride and potassium chloride, and aqueous solutions of the alkali metal salts. Another example of the electrolyte constituent 20 is water. Note that even if water, an alkali metal salt, or an aqueous solution of an alkali metal salt is stored inside the resin bag 21 made of a water-soluble resin, salting out occurs inside the resin bag 21, and the resin bag 21 does not dissolve and functions as a shell.

[0050] Furthermore, a shielding material such as a coating may be applied, if necessary, to a portion other than the boundary between the first portion 41 of the negative electrode 12 and the support member 13. Specifically, for example, a shielding material such as a coating may be applied to a portion such as a boundary between the second portion 42 of the negative electrode 12 and the extending portion 15 of the support member 13, or a portion such as a boundary between the extending portion 15 of the support member 13 and the support 22. By applying a shielding material such as a coating to these portions, corrosion of the positive electrode 11, the negative electrode 12, etc., caused by the electrolyte constituents 20 sealed in the resin bag 21 can be prevented, even if the resin bag 21 is damaged by corrosion due to atmospheric humidity or the influence of atmospheric moisture. Among the shielding materials, the coating material preferably has insulating properties, and examples thereof include silicone-based, fluorine-based, epoxy-based, polyvinyl chloride-based, polyethylene-based, and polyamide-based resins. Examples of shielding materials other than coatings include insulating tapes, rubber sheets, resin plates, films, and papers.

[0051] Examples of the active material for 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 in terms of power generation efficiency and availability.

[0052] The support member 13, which functions as a separator, is made of a material that is electrically insulating, ion-permeable, and liquid-permeable. Examples of materials that form the support member 13 include resins such as polyethylene, polypropylene, polyethylene terephthalate, cellulose, polyamide, and (meth)acrylic resin, as well as glass. The support member 13 is a member having voids, and examples thereof include nonwoven fabric, glass fiber, woven fabric having a mesh structure, and membrane members having independent pores or interconnected pores. Examples of materials that form the support member 13 and have voids include members having a porous structure.

[0053] The positive electrode 11 has a positive electrode current collector and a catalyst layer. The positive electrode current collector is a member that has conductivity to transfer electrons emitted from the negative electrode 12 to the catalyst layer and breathability to allow oxygen to pass through. Examples of the positive electrode current collector include wire mesh and foam metal. The catalyst layer functions as a reaction section of the positive electrode 11.

[0054] Next, a power generation system for 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, the case where the negative electrode 12 is made of magnesium (Mg) will be described here. When water comes into contact with the metal-air battery 10 and permeates the entire metal-air battery 10, an oxidation reaction shown in (1) below occurs at the negative electrode 12. Also, a reduction reaction shown in (2) below occurs at 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 its own power. (1) 2Mg → 2Mg2 + +4e - (2)O2 + 2H2O + 4e - →4OH - (3) 2Mg + O2 + 2H2O → 2Mg(OH)2

[0055] Next, a detection operation when the liquid detection sensor 1 detects water as a detection target will be described. As shown in FIG. 2, when water 110 as a detection target of the liquid detection sensor 1 comes into contact with the support 22 of the metal-air battery 10 of the liquid detection sensor 1, the water 110 then permeates throughout the support 22. As the water 110 as a detection target permeates throughout the support 22, the resin bag 21 formed of a resin that is soluble or dispersible 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. Furthermore, when the water 110 as a detection target permeates from the support 22 into the support member 13, the water 110 acts as an electrolyte, causing the metal-air battery 10 to discharge. When the metal-air battery 10 discharges, 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.

[0056] When the metal-air battery 10 generates power, the power from the metal-air battery 10 is supplied to the alarm unit 100 through the electric wire unit 101. When the alarm unit 100 receives the power generated from the metal-air battery 10, it notifies the detection of liquid by an alarm means provided in the alarm unit 100.

[0057] In the liquid detection sensor 1, the electrolyte constituent components 20 of the metal-air battery 10, which is the power source, are sealed inside a resin bag 21 that is soluble or dispersible in the liquid (water 110) to be detected, thereby enabling use in any field for detecting water 110 and improving versatility. Furthermore, in the liquid detection sensor 1, the electrolyte constituent components 20 of the metal-air battery 10 are sealed inside the resin bag 21, thereby preventing the metal-air battery 10 from deteriorating due to the electrolyte constituent components 20 even if the liquid detection sensor 1 is installed for a long period of time. Furthermore, in the liquid detection sensor 1, the electrolyte constituent components 20 of the metal-air battery 10 are sealed inside the resin bag 21, thereby enabling the use of electrolyte constituent components 20 that impart excellent power generation performance to the metal-air battery 10 while preventing deterioration of the metal-air battery 10, thereby enabling the metal-air battery 10 to exhibit excellent power generation performance and reliably transmitting an alarm to a location remote from the site of a leak or flooding. Therefore, the liquid detection sensor 1 can reliably transmit an alarm to a location far away from the site of the liquid leak or flooding, thereby improving convenience and versatility.

[0058] Furthermore, in the liquid detection sensor 1, the resin bag 21 containing the electrolyte component 20 is disposed opposite a second portion 42 of the negative electrode 12 that is different from the first portion 41 of the negative electrode 12 that faces the positive electrode 11. This prevents corrosion of the components constituting the metal-air battery 10, such as the positive electrode 11, the negative electrode 12, and the support member 13, caused by leakage of the electrolyte component 20, even if the resin bag 21 is damaged due to the influence of humidity or moisture in the atmosphere. In particular, in the liquid detection sensor 1, the second portion 42 of the negative electrode 12, which is disposed opposite the resin bag 21 containing the electrolyte component 20, faces the first portion 41 of the negative electrode 12 that faces the positive electrode 11. This more reliably prevents corrosion of the components constituting the metal-air battery 10, such as the positive electrode 11, the negative electrode 12, and the support member 13, caused by leakage of the electrolyte component 20, even if the resin bag 21 is damaged.

[0059] Furthermore, since the liquid detection sensor 1 has multiple resin bags 21 in which the electrolyte constituents 20 are sealed, the electrolyte constituents 20 are smoothly supplied to the entire metal-air battery 10, thereby further improving the power generation efficiency of the metal-air battery 10.

[0060] Next, a liquid detection sensor according to a second embodiment of the present invention will be described. Note that the main parts of the liquid detection sensor according to the second embodiment are common to 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 an overview 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.

[0061] In the liquid detection sensor 1 according to the first embodiment, the extending portion 15 of the support member 13 is disposed between the support 22 holding the resin bag 21 containing the electrolyte component 20 and the second portion 42 of the negative electrode 12. However, as shown in FIG. 3 , in the liquid detection sensor 2 according to the second embodiment, the support 22 holding the resin bag 21 containing the electrolyte component 20 is disposed between the extending portion 15 of the support member 13 and the second portion 42 of the negative electrode 12. That is, the resin bag 21 containing the electrolyte component 20 is disposed between the extending portion 15 of the support member 13 and the second portion 42 of the negative electrode 12. Therefore, the extending portion 15 of the support member 13 faces the second portion 42 of the negative electrode 12 via the resin bag 21 containing the electrolyte component 20.

[0062] Furthermore, in the liquid detection sensor 2, a coating may be applied, if necessary, to a portion other than the boundary between the first portion 41 of the negative electrode 12 and the support member 13. Specifically, for example, a coating may be applied to the boundary between the second portion 42 of the negative electrode 12 and the support member 22, or the boundary between the extension portion 15 of the support member 13 and the support member 22. By applying a coating to the above-mentioned portions, corrosion of the positive electrode 11, the negative electrode 12, etc., caused by the electrolyte constituent components 20 sealed in the resin bag 21 can be prevented even if the resin bag 21 is damaged by corrosion due to atmospheric humidity or the influence of moisture in the atmosphere.

[0063] As shown in Fig. 4, in the liquid detection sensor 2, when water 110, which is the detection target, comes into contact with the support 22 of the metal-air battery 10 of the liquid detection sensor 2, it permeates throughout the support 22. As the water 110, which is the detection target, permeates throughout the support 22, the resin bag 21, which is made of a resin that is soluble or dispersible in the water 110, dissolves or disperses. 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. Furthermore, when the water 110, which is the detection target, permeates from the support 22 into the support member 13, the water 110 acts as an electrolyte, causing the metal-air battery 10 to discharge. When the metal-air battery 10 discharges, 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.

[0064] In the liquid detection sensor 2, the electrolyte constituents 20 of the metal-air battery 10 are sealed inside the resin bag 21 that is soluble or dispersible in the liquid to be detected (water 110), thereby enabling use in any field for detecting water 110 and improving versatility. In addition, in the liquid detection sensor 2, the electrolyte constituents 20 of the metal-air battery 10 are sealed inside the resin bag 21, thereby preventing the metal-air battery 10 from being deteriorated by the electrolyte constituents 20 even when the liquid detection sensor 2 is installed for a long period of time. In addition, in the liquid detection sensor 2, the resin bag 21 in which the electrolyte constituents 20 are sealed is disposed opposite the second portion 42 of the negative electrode 12, which is different from the first portion 41 of the negative electrode 12 that faces the positive electrode 11. Therefore, even if the resin bag 21 is damaged by the influence of atmospheric humidity or moisture, corrosion of the components constituting the metal-air battery 10, such as the positive electrode 11, the negative electrode 12, and the support member 13, due to leakage of the electrolyte constituents 20 can be prevented.

[0065] Next, a liquid detection sensor according to a third embodiment of the present invention will be described. Note that the main parts of the liquid detection sensor according to the third embodiment are common to the liquid detection sensors according to the first and second embodiments, and therefore the same components as those of the liquid detection sensors according to the first and second embodiments will be described using the same reference numerals. Note that Fig. 5 is a side view illustrating an overview of the liquid detection sensor according to the third embodiment of the present invention, and Fig. 6 is a side view illustrating the state of the liquid detection sensor according to the third embodiment of the present invention when detecting liquid.

[0066] The liquid detection sensor 1 according to the first embodiment is a water detection sensor, and the resin bag 21 is made of a resin that is soluble or dispersible in water. Instead, the liquid detection sensor 3 according to the third embodiment is an oil detection sensor, and therefore the resin bag 31 in which the electrolyte constituents 30 are sealed is made of a resin that is soluble or dispersible in oil.

[0067] 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 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 appropriately changed.

[0068] As shown in FIG. 5 , in the negative electrode 12 of the liquid detection sensor 3, the second region 42 faces the first region 41, and a resin bag 31 containing the electrolyte solution constituents 30 is disposed opposite the second region 42 of the negative electrode 12. The extending portion 15 of the support member 13 extends from the first region 41 to the position of the resin bag 31 containing the electrolyte solution constituents 30 disposed opposite the second region 42. The extending portion 15 of the support member 13 is disposed between the resin bag 31 containing the electrolyte solution constituents 30 and the second region 42. Therefore, the resin bag 31 containing the electrolyte solution constituents 30 faces the second region 42 of the negative electrode 12 via the extending portion 15 of the support member 13.

[0069] In the metal-air battery 10 of the liquid detection sensor 3, there are also a plurality of resin bags 31 in which the electrolyte constituents 30 are sealed, and the electrolyte constituents 30 are divided into a plurality of portions, each containing a fixed amount, and sealed inside each of the resin bags 31. A support 22 is disposed opposite the second portion 42 of the negative electrode 12, and the plurality of resin bags 31, 31, 31, ... in which the electrolyte constituents 30 are sealed are held by the support 22. The support 22 is a separate member from the positive electrode 11, the negative electrode 12, and the support member 13, and is also a separate member from the positive electrode 11, the negative electrode 12, and the support member 13.

[0070] The resin bag 31 is formed of, for example, an oil-soluble resin, which is a resin that is soluble or dispersible in oil. By forming the resin bag 31 of the oil-soluble resin, the liquid detection sensor 3 functions as an oil detection sensor.

[0071] 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. These compounds may be used alone or in combination of two or more.

[0072] The method for encapsulating the electrolyte solution constituents 30 in the resin bag 31 is not particularly limited, and examples thereof include a method of placing the electrolyte solution constituents 30 into the resin bag 31 through the opening of the resin bag 31 and then encapsulating the components by gluing or heat-sealing the opening of the resin bag 31, or a method of encapsulating the components by a microcapsule manufacturing method using a W / O dispersion or an O / W dispersion. The method for supporting the plurality of resin bags 31 encapsulating the electrolyte solution constituents 30 on the support member 13 is also not particularly limited, and examples thereof include a method of pressurizing the resin bags 31 into voids in the support member 13, a method of dispersing the resin bags 31 in a dispersion medium such as a solvent and then impregnating the support member 13 with the dispersion medium being dried and removed, and a method of dividing the support member 13 into a plurality of sections, arranging the resin bags 31 between the sections, and then adhering the support member 13 to the sections.

[0073] The oil that is the detection target of the liquid detection sensor 3 is not a constituent component 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 component 30. Examples of the electrolyte solution constituent component 30 include water containing an alkali metal salt such as sodium chloride or potassium chloride (aqueous solution of alkali metal salt), or water.

[0074] Next, a detection operation when the liquid detection sensor 3 detects oil, which is the detection target, will be described. As shown in FIG. 6 , when the oil 120, which is the detection target of the liquid detection sensor 3, comes into contact with the support 22 of the metal-air battery 10 of the liquid detection sensor 3, it then permeates throughout the support 22. As the oil 120, which is the detection target, permeates throughout the support 22, the resin bag 31, which is made of a resin that is soluble or dispersible in the oil 120, dissolves or disperses. In other words, the resin bag 31 is destroyed by the oil 120, which is the detection target. When the resin bag 31 dissolves or disperses, the electrolyte constituents 30 (e.g., an aqueous solution of an alkali metal salt) sealed in the resin bag 31 are released into the oil 120. The electrolyte constituents 30 released into the oil 120 act as an electrolyte, causing the metal-air battery 10 to discharge. When the metal-air battery 10 discharges, an aqueous solution of alkali metal salt is released from the resin bag 31 as the electrolyte, and the action of the electrolyte constituents 30 improves 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.

[0075] The liquid detection sensor 3 can be used to detect oil because the electrolyte constituents 30 of the metal-air battery 10, which is the power source, are sealed inside a resin bag 31 that is soluble or dispersible in the oil 120 to be detected. Furthermore, because the electrolyte constituents 30 of the metal-air battery 10 are sealed inside the resin bag 31, the liquid detection sensor 3 can prevent the metal-air battery 10 from being deteriorated by the electrolyte constituents 30 even if the liquid detection sensor 3 is installed for a long period of time. Furthermore, in the liquid detection sensor 3, the resin bag 31 containing the electrolyte constituents 30 is disposed opposite a second portion 42 of the negative electrode 12 that is different from the first portion 41 of the negative electrode 12 that faces the positive electrode 11. Therefore, even if the resin bag 31 is damaged, corrosion of the components of the metal-air battery 10, such as the positive electrode 11, the negative electrode 12, and the support member 13, caused by leakage of the electrolyte constituents 30 can be prevented.

[0076] Next, a liquid detection sensor according to a fourth embodiment of the present invention will be described. Note that the main parts of the liquid detection sensor according to the fourth embodiment are common to the liquid detection sensors according to the first to third embodiments, and therefore the same components as those of the liquid detection sensors according to the first to third embodiments will be described using the same reference numerals. Note that Fig. 7 is a side view illustrating an overview of the liquid detection sensor according to the fourth embodiment of the present invention, and Fig. 8 is a side view illustrating the state of the liquid detection sensor according to the fourth embodiment of the present invention when detecting liquid.

[0077] In the liquid detection sensor 3 according to the third embodiment, the extending portion 15 of the support member 13 is disposed between the support 22 holding the resin bag 31 containing the electrolyte component 30 and the second portion 42 of the negative electrode 12. However, as shown in FIG. 7 , in the liquid detection sensor 4 according to the fourth embodiment, the support 22 holding the resin bag 31 containing the electrolyte component 30 is disposed between the extending portion 15 of the support member 13 and the second portion 42 of the negative electrode 12. That is, the resin bag 31 containing the electrolyte component 30 is disposed between the extending portion 15 of the support member 13 and the second portion 42 of the negative electrode 12. Therefore, the extending portion 15 of the support member 13 faces the second portion 42 of the negative electrode 12 via the resin bag 31 containing the electrolyte component 30.

[0078] As shown in FIG. 8 , when the oil 120 to be detected by the liquid detection sensor 4 comes into contact with the support 22 of the metal-air battery 10 of the liquid detection sensor 4, the oil 120 then permeates throughout the support 22. As the oil 120 to be detected permeates throughout the support 22, the resin bag 31, which is made of a resin that is soluble or dispersible in the oil 120, dissolves or disperses. When the resin bag 31 dissolves or disperses, the electrolyte constituents 30 (e.g., an aqueous solution of an alkali metal salt) sealed in the resin bag 31 are released into the oil 120. The electrolyte constituents 30 released into the oil 120 act as an electrolyte, causing the metal-air battery 10 to discharge. When the metal-air battery 10 discharges, the aqueous solution of the alkali metal salt is released from the resin bag 31 as the electrolyte. The electrolyte constituents 30 act to improve ionic conductivity between the positive electrode 11 and the negative electrode 12, improving the power generation performance of the metal-air battery 10.

[0079] The liquid detection sensor 4 can also be used to detect oil because the electrolyte constituents 30 of the metal-air battery 10 are sealed inside the resin bag 31, which is soluble or dispersible in the oil 120 to be detected. Furthermore, because the electrolyte constituents 30 of the metal-air battery 10 are sealed inside the resin bag 31, the metal-air battery 10 can be prevented from being deteriorated by the electrolyte constituents 30 even if the liquid detection sensor 4 is installed for a long period of time. Furthermore, because the resin bag 31 in which the electrolyte constituents 30 are sealed is disposed opposite a second portion 42 of the negative electrode 12 that is different from the first portion 41 of the negative electrode 12 that faces the positive electrode 11, even if the resin bag 31 is damaged, corrosion of the components of the metal-air battery 10, such as the positive electrode 11, the negative electrode 12, and the support member 13, caused by leakage of the electrolyte constituents 30 can be prevented.

[0080] Next, an example of how to use the liquid detection sensor of the present invention will be described. For convenience of explanation, the example of how to use 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. 9 is an explanatory diagram of the example of how to use the liquid detection sensor of the present invention.

[0081] As shown in FIG. 9 , the alarm unit 100 connected to the metal-air battery 10 via an electric wire unit 101 is, for example, a transmitter that receives power generated from the metal-air battery 10 and activates a transmission function to the receiver unit 200. When the metal-air battery 10 detects a liquid to be detected (water 110 in FIG. 9 ) and generates power, the alarm unit 100 receives power from the metal-air battery 10, activates its transmission function, and transmits a detection signal to the receiver unit 200. Examples of the transmitter include a wireless transmitter and a wired transmitter. In FIG. 9 , a wireless transmitter is used as the alarm unit 100, allowing the alarm unit 100 to wirelessly transmit a detection signal to the receiver unit 200. For wireless communication, an existing wireless method such as wireless LAN, Bluetooth (registered trademark), or Wi-Fi can be used.

[0082] 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 of the liquid to be detected (in Figure 9, a water leak or flooding) has occurred, notifies the administrator of the occurrence of the water leak or flooding, and also automatically stops the device, etc., if necessary.

[0083] Next, a liquid detection sensor according to another embodiment of the present invention will be described. In the liquid detection sensors according to the first to fourth embodiments described above, a plurality of resin bags containing electrolyte constituents are dispersedly disposed over the entire support body. However, instead of this, a single resin bag may be provided. In this case, the electrolyte constituents are encapsulated in a single resin bag.

[0084] Furthermore, in the liquid detection sensors according to the first and second embodiments, the resin bag is formed from a water-soluble resin, and in the liquid detection sensors according to the third and fourth embodiments, the resin bag is formed from an oil-soluble resin, but instead, a single metal-air battery may use both a resin bag formed from a water-soluble resin and a resin bag formed from an oil-soluble resin. By using both a resin bag made from a water-soluble resin and a resin bag made from an oil-soluble resin, a single liquid detection sensor can detect both water and oil.

[0085] In addition, in the above-described example of the method of using the liquid detection sensor, the notification unit was a transmitter having a function of transmitting to the receiver, but instead, it may be a liquid detection display unit that receives power from the metal-air battery and notifies a manager of the detection of liquid. Examples of display means for the liquid detection display unit include turning on a warning light and emitting a warning sound. [Industrial Applicability]

[0086] The liquid detection sensor of the present invention is versatile and can prevent deterioration of the metal-air battery, which is its power source, even when installed for a long period of time. In addition, the metal-air battery, which is its 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 water levels in rivers, lakes, etc. to detect when dangerous water levels have been reached, detecting blood and drug leaks in medical settings, and detecting urination in nursing care settings. [Explanation of symbols]

[0087] 1, 2, 3, 4 Liquid detection sensor 10 Metal-air battery 11 Positive electrode 12 Negative electrode 20, 30 Electrolyte components 21, 31 Resin bag body 41 First Part 42 Second Part 100 Information Department

Claims

1. a metal-air battery including a positive electrode, a negative electrode having a first portion facing the positive electrode, and an electrolyte solution component disposed opposite a second portion of the negative electrode different from the first portion; The liquid detection sensor has the electrolyte constituent components sealed inside a resin bag, and the resin of the resin bag has solubility or dispersibility in the liquid to be detected.

2. 2. The liquid detection sensor according to claim 1, wherein the second portion of the resin bag in which the electrolyte constituents are sealed and disposed opposite each other has an area facing the first portion.

3. 3. The liquid detection sensor according to claim 1, wherein a support member is further provided between the positive electrode and the first portion to support the positive electrode and the first portion at a predetermined distance, and the support member has an extension portion that extends from the first portion to a position of the resin bag opposite the second portion in which the components of the electrolyte solution are sealed.

4. 4. The liquid detection sensor according to claim 3, wherein the extending portion of the support member is disposed between the resin bag in which the constituent components of the electrolyte are sealed and the second portion.

5. 4. The liquid detection sensor according to claim 3, wherein the resin bag containing the electrolyte constituents is disposed between the extending portion of the support member and the second portion.

6. 6. 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.

7. 7. The liquid detection sensor according to claim 1, wherein the resin bag in which the components of the electrolyte solution are sealed is one or more.

8. 8. 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.

9. 9. 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).

10. 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.

11. 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.

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

13. The liquid detection sensor according to any one of claims 1 to 11, which is an oil detection sensor.

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