Liquid detection sensor

Abstract

To provide a liquid detection sensor having versatility, capable of preventing deterioration in a metal-air battery as a power source even when installed for a long period of time, and capable of allowing the metal-air battery as the power source to exhibit excellent power generation performance.SOLUTION: A liquid detection sensor includes a metal-air battery having a positive electrode, a negative electrode, and electrolyte components located between the positive electrode and the negative electrode. The electrolyte components are enclosed inside a resin bag body, and a resin of the resin bag body has solubility or dispersibility in a liquid to be detected.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] Liquid detection sensors may be used in buildings, underground facilities, factories, medical sites, etc. to detect liquid leakage and flooding. The liquid detection sensor is arranged at a location where liquid leakage and flooding should be prevented. The liquid detection sensor detects liquid leakage by capturing an electrical change that occurs when a liquid contacts from the outside.

[0003] As a liquid detection sensor, for example, there is a liquid detection sensor for a medical site provided with a water battery that generates electricity by a leaked liquid (Patent Document 1). In Patent Document 1, the water battery is fixed on an absorbent member by an adhesive fixed tape, and a liquid such as blood or drip solution absorbed and diffused by the absorbent member is supplied to the entire water battery, so that the water battery generates electricity and detects liquid leakage.

[0004] Further, as a liquid detection sensor, for example, there is a liquid detection sensor for a medical site provided with a liquid leakage sensor portion composed 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 is electrically connected to the liquid leakage sensor portion, and a transmitter that transmits a detection signal by the power of the magnesium battery, a receiver that receives the detection signal transmitted from the transmitter, and a receiving terminal having an alarm means for alarming a liquid leakage state based on the detection signal from the receiver. The liquid leakage sensor portion detects a state in which the magnesium battery generates electricity using blood or an injection solution leaked from an injection needle as an electrolyte as a liquid leakage state.

[0005] Although it is necessary to accurately detect liquid leakage, in the liquid detection sensors of Patent Documents 1 and 2 in which a detection target such as blood functions as an electrolyte, there is no particular proposal other than the detection of blood and the like in a medical site as a liquid detection target.

[0006] On the other hand, detecting liquid leaks and flooding is required not only in medical settings but also in a wide range of fields such as buildings, underground facilities, and factories, and liquid detection sensors are sometimes required to be versatile, such as detecting water or oil. However, as mentioned above, the liquid detection sensors in Patent Documents 1 and 2 lack versatility.

[0007] Furthermore, in order to enhance the versatility of liquid detection sensors, when monitoring liquid leaks or flooding in buildings, underground facilities, factories, etc., monitors may sometimes monitor from a location away from the site of the leak or flooding. To ensure that liquid detection sensors reliably transmit alarms to locations far from the site of the leak or flooding, it is necessary to improve the power generation performance of the batteries installed in the liquid detection sensors.

[0008] When a metal-air battery is used as a power source for a liquid detection sensor, the power generation performance of the metal-air battery can be improved by using alkali metal salts such as sodium chloride or potassium chloride as the electrolyte. For example, if an alkali metal salt is pre-soaked in the separator of the metal-air battery, and the separator containing the alkali metal salt comes into contact with water, the ionic conductivity between the positive and negative electrodes is improved by the action of the water containing the alkali metal salt, allowing the metal-air battery to exhibit superior power generation performance.

[0009] However, if a liquid detection sensor is left installed for a long period of time with an alkali metal salt contained in the separator, the alkali metal salt in the separator may absorb moisture and liquefy, degrading 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 in that leakage or water ingress cannot be detected accurately. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] International Publication No. 2012 / 020507 [Patent Document 2] Japanese Patent Publication No. 2017-148332 [Overview of the project] [Problems that the invention aims to solve]

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

[0012] The gist of the present invention is as follows: [1] A metal-air battery comprising a positive electrode, a negative electrode, and an electrolyte component located between the positive electrode and the negative electrode, A liquid detection sensor in which the electrolyte components are sealed inside a resin bag, 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 is a water-soluble resin or an oil-soluble resin. [3] The liquid detection sensor according to [1] or [2], wherein the resin bag containing the electrolyte components is one or more. [4] A liquid detection sensor according to any one of [1] to [3], further comprising a support member having a gap between the positive electrode and the negative electrode and supporting the positive electrode and the negative electrode. [5] The liquid detection sensor according to [4], wherein the resin bag containing the electrolyte components is supported on the support member. [6] The liquid detection sensor according to any one of [1] to [5], wherein the resin bag containing the electrolyte components is disposed between the positive electrode and the negative electrode. [7] The liquid detection sensor according to [4], wherein the resin bag containing the electrolyte components is disposed between the support member and the positive electrode and / or between the support member and the negative electrode. [8] A liquid detection sensor according to any one of [1] to [7], wherein the electrolyte component comprises water, an alkali metal salt, or an aqueous solution of an alkali metal salt. [9] A liquid detection sensor according to any one of [1] to [8], wherein the active material of the negative electrode comprises at least one metal selected from the group consisting of magnesium (Mg), aluminum (Al), lithium (Li), calcium (Ca), and zinc (Zn).

[10] A liquid detection sensor according to any one of [1] to [9], having a notification unit that receives power from the metal-air battery to indicate liquid detection.

[11] A liquid detection sensor according to any one of [1] to [9], having a notification unit capable of wirelessly transmitting a detection signal of the metal-air battery to a receiving unit.

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

[11] , which is a water detection sensor.

[13] An oil detection sensor, the liquid detection sensor described in any one of [1] to

[11] .

[0013] In the embodiment described in [1] above, 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 bag dissolves in the liquid to be detected, and the electrolyte components sealed inside the resin bag are released between the positive and negative electrodes of the metal-air battery. As the electrolyte components are released between the positive and negative electrodes of the metal-air battery, the metal-air battery generates power or its power generation performance improves, and the liquid detection sensor notifies the outside that the liquid to be detected has been detected because the metal-air battery is generating power. [Effects of the Invention]

[0014] According to an aspect of the liquid detection sensor of the present invention, since the electrolyte component of the metal-air battery as a power source is enclosed inside a resin bag having solubility in the liquid to be detected, by appropriately selecting the resin type of the resin bag, the versatility such as water detection and oil detection is improved. Further, according to an aspect of the liquid detection sensor of the present invention, since the electrolyte component of the metal-air battery is enclosed inside the resin bag, it is possible to prevent the metal-air battery from being deteriorated by the electrolyte component even when the liquid detection sensor is installed for a long period. Further, according to an aspect of the liquid detection sensor of the present invention, since the electrolyte component of the metal-air battery is enclosed inside the resin bag, it is possible to use an electrolyte component that imparts excellent power generation performance to the metal-air battery while preventing deterioration of the metal-air battery, so that the metal-air battery can exhibit excellent power generation performance.

[0015] According to an aspect of the liquid detection sensor of the present invention, when the resin of the resin bag is a water-soluble resin, it functions as a water detection sensor, and when the resin of the resin bag is an oil-soluble resin, it functions as an oil detection sensor.

[0016] According to an aspect of the liquid detection sensor of the present invention, when there are a plurality of resin bags enclosing the electrolyte components, the electrolyte components are smoothly supplied to the entire electrode, so that the power generation efficiency of the metal-air battery is improved.

Brief Description of Drawings

[0017] [Figure 1] It is a side view for explaining the outline of the liquid detection sensor according to the first embodiment of the present invention. [Figure 2] It is a side view for explaining the state at the time of liquid detection of the liquid detection sensor according to the first embodiment of the present invention. [Figure 3] It is a side view for explaining the outline of the liquid detection sensor according to the second embodiment of the present invention. [Figure 4] It is a side view for explaining the state at the time of liquid detection of the liquid detection sensor according to the second embodiment of the present invention. [Figure 5] It is a side view for explaining the outline of the liquid detection sensor according to the third embodiment of the present invention. [Figure 6] This is an explanatory diagram illustrating an example of how to use the liquid detection sensor of the present invention. [Modes for carrying out the invention]

[0018] The following describes in detail the liquid detection sensor according to an embodiment of the present invention. First, the liquid detection sensor according to the first embodiment of the present invention will be described. Figure 1 is a side view illustrating the overview of the liquid detection sensor according to the first embodiment of the present invention, and Figure 2 is a side view illustrating the state of the liquid detection sensor according to the first embodiment of the present invention when liquid is detected.

[0019] As shown in Figure 1, the liquid detection sensor 1 according to the first embodiment of the present invention comprises a metal-air battery 10 and a notification unit 100 connected to the metal-air battery 10 via a wire section 101. The notification unit 100 has the function of notifying of liquid detection via a notification means when it receives power generated from the metal-air battery 10 via the wire section 101.

[0020] The metal-air battery 10 comprises a positive electrode 11, a negative electrode 12 facing the positive electrode 11, and a separator 13 having an air gap 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 sheet form and have a laminated structure in which the positive electrode 11, the separator 13, and the negative electrode 12 are stacked in that order. The peripheral edge 14 of the separator 13 extends outward from 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 distance in order 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, the electrolyte component 20 is placed between the positive electrode 11 and the negative electrode 12. That is, the electrolyte component 20 is interposed between the positive electrode 11 and the negative electrode 12. The electrolyte component 20 is either a component of the electrolyte of the metal-air battery 10 or the electrolyte of the metal-air battery 10. The metal-air battery 10 starts generating electricity on its own when the positive electrode 11 and the negative electrode 12 come into contact with the electrolyte.

[0022] As shown in Figure 1, the electrolyte components 20 are sealed inside the resin bag 21. Therefore, the electrolyte components 20 are not in contact with either the positive electrode 11 or the negative electrode 12. The resin bag 21 can be, for example, a thin film bag, a film-like bag, or a capsule-like material such as a microcapsule. The resin bag 21 contains the electrolyte components 20 and seals a certain amount of the electrolyte components 20. Therefore, the resin bag 21 functions as a shell.

[0023] In the metal-air battery 10, there are multiple resin bags 21 containing the electrolyte components 20, and the electrolyte components 20 are divided into multiple fixed amounts and sealed inside each resin bag 21. The resin bags 21 containing the electrolyte components 20 are supported on a separator 13 having a porous structure. Because the resin bags 21 containing the electrolyte components 20 are supported on the separator 13, the electrolyte components 20 are interposed between the positive electrode 11 and the negative electrode 12. The resin bags 21 containing the electrolyte components 20 are supported in a dispersed state on the surface and inside the separator 13. In Figure 1, multiple resin bags 21 containing the electrolyte components 20 are supported throughout the separator 13.

[0024] The resin bag 21 is made of a resin that is soluble in 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 made of, for example, a water-soluble resin. Because the resin bag 21 is made of a water-soluble resin, the liquid detection sensor 1 functions as a water detection sensor.

[0025] Examples of water-soluble resins include resin compositions comprising 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 adding 1 to 4 moles of alkylene oxide to 1 mole of a 3 to 6 valent polyhydric alcohol.

[0026] Polyvinyl alcohol-based 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 individually 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 esters and the sulfonic acid group or its salt is present in the polyvinyl alcohol-based resin after saponification. Specifically, examples include 2-(meth)acrylamide-2-methylpropanesulfonic acid, alkali metal salts of 2-(meth)acrylamide-2-methylpropanesulfonic acid, 2-(meth)acrylamide-1-methylpropanesulfonic acid, alkali metal salts of 2-(meth)acrylamide-1-methylpropanesulfonic acid, olefin sulfonic acids such as ethylene sulfonic acid, allyl sulfonic acid, and metaallyl sulfonic acid, and metal salts of the aforementioned olefin sulfonic acids. These compounds may be used alone or in combination of two or more. In this specification, "(meth)acrylic" means "acrylic and / or methacrylic".

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

[0029] The content of the above copolymer units in the polyvinyl alcohol resin is not particularly limited, but for example, 0.1 to 20 mol% is given due to the excellent balance between water solubility and mechanical strength. The degree of saponification of the polyvinyl alcohol resin (A) is, for example, 40 mol% to 100 mol%. The viscosity-average degree of polymerization of the polyvinyl alcohol resin (A) is, for example, 200 to 10000.

[0030] Examples of polyhydric alcohols with 3-6 valent values ​​that serve as raw materials for addition product (B) include glycerin, trimethylolpropane, diglycerin, pentaerythritol, xylose, arabinose, ribulose, and sorbitol. Examples of alkylene oxides that serve as raw materials for addition product (B) include ethylene oxide and propylene oxide. These compounds may be used individually or in combination of two or more.

[0031] One method for forming a film from the above resin composition is, for example, by casting an aqueous solution of the resin composition. The resin bag 21 of the above resin composition has a fast dissolution rate in water, maintains its water solubility even when the electrolyte components 20 are sealed inside for a long period of time, and also has excellent mechanical strength.

[0032] Furthermore, as a water-soluble resin, a resin composite of a polyvinyl alcohol polymer and at least one resin selected from polysaccharides and acrylic resins can be mentioned. An example of a resin bag 21 using a resin composite is a resin laminate having a first layer containing a polyvinyl alcohol polymer and a second layer containing at least one resin selected from polysaccharides and acrylic resins.

[0033] Examples of polyvinyl alcohol polymers include those prepared by polymerizing vinyl ester monomers and saponifying the resulting polyvinyl ester polymer. 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 individually or in combination of two or more.

[0034] Polyvinyl alcohol polymers may be copolymers of vinyl ester monomers and other monomers polymerizable with vinyl ester monomers. Other monomers include, for example, 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)acrylamides such as (meth)acrylamide, N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, diacetone(meth)acrylamide, (meth)acrylamidepropyldimethylamine, and N-methylol(meth)acrylamide; methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, dodecyl vinyl ether, and stearyl vinyl ether. Examples include vinyl ethers such as ruether; 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; vinylamides such as N-vinylformamide, N-methyl-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)acrylamide-2-methylpropanesulfonic acid, 2-(meth)acrylamide-1-methylpropanesulfonic acid, ethylenesulfonic acid, allylsulfonic acid, and methacrylicsulfonic acid. These compounds may be used individually or in combination of two or more.

[0035] The degree of saponification of the polyvinyl alcohol polymer is, for example, 75 mol% to 99 mol%. The viscosity-average degree of polymerization of the polyvinyl alcohol polymer is, for example, 300 to 2500. Methods for preparing the first layer include, for example, using a polyvinyl alcohol polymer solution obtained by dissolving the polyvinyl alcohol polymer in a solvent (e.g., casting method, solution coating method, wet film formation method, gel film formation method, etc.).

[0036] The second layer contains at least one resin selected from polysaccharides and acrylic resins. Examples of polysaccharides in the second layer include starches and cellulosic resins.

[0037] Examples of starches include naturally derived starches such as potato starch, corn starch, wheat starch, and rice starch; starches that have been heat-gelatinized and dried from naturally derived starches; and modified starches such as acetylated oxidized starch, sodium octenyl succinate starch, acetic acid starch, oxidized starch, hydroxypropyl starch, hydroxypropylated phosphate cross-linked starch, phosphate monoesterified phosphate cross-linked starch, phosphorylated starch, and nitrate starch. Examples of cellulosic resins include carboxymethylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, hydroxyethylmethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, and methylcellulose. These compounds may be used individually or in combination of two or more.

[0038] Examples of acrylic resins include polyacrylamide.

[0039] Methods for preparing the second layer include, for example, using a resin solution obtained by dissolving at least one resin selected from polysaccharides and acrylic resins in a solvent (e.g., casting method, solution coating method, wet film formation method).

[0040] Methods for preparing a resin laminate having a first layer and a second layer include, for example, a method of preparing the first and second layers in advance and laminating the first and second layers; a method of coating a pre-prepared first layer with a coating solution for forming a second layer containing at least one resin selected from polysaccharides and acrylic resins; a method of coating a pre-prepared second layer with a coating solution for forming a first layer containing a polyvinyl alcohol polymer; a method of co-extruding the first and second layers; and a method of manufacturing the first layer by extruding or coating the second layer onto the first layer before the first layer is completely dry or cooled, and then drying or cooling the first and second layers simultaneously.

[0041] Other water-soluble resins besides those listed above include water-soluble vinyl resins such as polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, and polyvinylmethylene ether; polyether resins such as polyethylene oxide; cellulose resins such as carboxymethylcellulose, hydroxypropylcellulose, and hydroxyethylcellulose; acrylic resins such as poly(meth)acrylate; and polysaccharide polymers such as alginic acid, pullulan, and xanthan gum.

[0042] The method for encapsulating the electrolyte components 20 in the resin bag is not particularly limited. Examples include a method in which the electrolyte components 20 are placed into the resin bag through its opening, and then the opening is sealed by bonding and heat welding. Another method is to encapsulate the components using a microcapsule manufacturing method that utilizes W / O dispersion or O / W dispersion. Furthermore, the method for supporting multiple resin bags 21 containing the electrolyte components 20 on the separator 13 is not particularly limited. Examples include a method in which the resin bags 21 are pressed into the voids of the separator 13. Another method is to disperse the resin bags 21 in a dispersion medium such as a solvent, then impregnate the separator 13 with the dispersion medium and dry it off. Finally, the separator 13 is divided into multiple sections, the resin bags 21 are placed between them, and then the separator 13 is bonded together.

[0043] Examples of electrolyte components 20 enclosed in a resin bag 21 made of a water-soluble resin include alkali metal salts such as sodium chloride and potassium chloride, or aqueous solutions of the alkali metal salts. Another example of an electrolyte component 20 is water. Even if water, alkali metal salts, or aqueous solutions of alkali metal salts are placed inside the resin bag 21 made of a water-soluble resin, salting out occurs inside the resin bag 21, so the resin bag 21 does not dissolve and functions as a shell.

[0044] Examples of active materials 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. Of these, magnesium (Mg) and magnesium alloys are preferred from the viewpoint of power generation efficiency and availability.

[0045] The separator 13 is formed from a material that has electrical insulation, ion permeability, and liquid permeability. Examples of materials for forming the separator 13 include polyethylene, polypropylene, polyethylene terephthalate, cellulose, polyamide, resins such as acrylic resin, and glass. The separator 13 is also a void-containing member, such as a nonwoven fabric, glass fiber, a woven fabric with a mesh structure, or a membrane member with independent holes or connecting holes. Examples of void-containing members constituting the separator 13 include members with a porous structure.

[0046] The positive electrode 11 comprises a positive electrode current collector and a catalyst layer. The positive electrode current collector is a material that possesses conductivity to transmit electrons emitted from the negative electrode 12 to the catalyst layer and permeability to allow oxygen to pass through. Examples of the positive electrode current collector include wire mesh and foamed metal. The catalyst layer functions as the reaction part of the positive electrode.

[0047] Next, we will explain the power generation system of the metal-air battery 10 when water, which is the target of detection by the liquid detection sensor 1, comes into contact with the metal-air battery 10. For the sake of explanation, we will describe the case where the negative electrode 12 is magnesium (Mg). When water comes into contact with the peripheral edge 14 of the separator 13 and penetrates the entire separator 13, the oxidation reaction shown in (1) below occurs at the negative electrode 12. Also, the 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, that is, generates its own power. (1) 2Mg → 2Mg 2+ +4e - (2) O2 + 2H2O + 4e - →4OH - (3) 2Mg + O2 + 2H2O → 2Mg(OH)2

[0048] Next, the detection operation when the liquid detection sensor 1 detects water will be explained. As shown in Figure 2, when the water 110 to be detected comes into contact with the metal-air battery 10 of the liquid detection sensor 1, it comes into contact with the peripheral edge 14 of the separator 13 and then permeates throughout the entire separator 13. As the water 110 to be detected permeates throughout the entire separator 13, the resin bag 21, which is made of a resin that is soluble or dispersible in water 110, dissolves or disperses. In other words, the resin bag 21 is destroyed by the water 110 to be detected. When the resin bag 21 dissolves or disperses, the electrolyte components 20 (for example, sodium chloride, water containing sodium chloride) that were sealed in the resin bag 21 are released into the water 110. Also, as described above, when the water 110 to be detected permeates the separator 13, the water 110 acts as an electrolyte, so the metal-air battery 10 discharges. When the metal-air battery 10 discharges, the water 110 acting as the electrolyte contains electrolyte components 20 released from the resin bag 21. As a result, the ionic conductivity between the positive electrode 11 and the negative electrode 12 improves due to the action of the electrolyte components 20, thereby improving the power generation performance of the metal-air battery 10.

[0049] 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 power line section 101. When the notification unit 100 receives the power generated from the metal-air battery 10, it notifies the liquid detection using the notification means provided in the notification unit 100.

[0050] In the liquid detection sensor 1, the electrolyte 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 water 110, which is the target of detection. This allows the sensor to be used in any field for water detection, improving its versatility. Furthermore, in the liquid detection sensor 1, because the electrolyte components 20 of the metal-air battery 10 are sealed inside the resin bag 21, the metal-air battery 10 can be prevented from degrading by the electrolyte components 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, because the electrolyte components 20 of the metal-air battery 10 are sealed inside the resin bag 21, the metal-air battery 10 can be used with an electrolyte component 20 that provides excellent power generation performance to the metal-air battery 10 while preventing degradation of the metal-air battery 10, thus enabling the metal-air battery 10 to exhibit excellent power generation performance. Furthermore, since the metal-air battery 10 exhibits excellent power generation performance, the amount of power received by the notification unit 100 increases, and the notification performance of the notification unit 100 is improved.

[0051] Furthermore, in the liquid detection sensor 1, since there are multiple resin bags 21 containing the electrolyte components 20, the electrolyte components 20 are smoothly supplied to the entire electrode, thereby improving the power generation efficiency of the metal-air battery 10.

[0052] Next, a liquid detection sensor according to the second embodiment of the present invention will be described. Since 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, the same reference numerals will be used to describe the same components as those in the liquid detection sensor according to the first embodiment. Figure 3 is a side view illustrating the overview of the liquid detection sensor according to the second embodiment of the present invention, and Figure 4 is a side view illustrating the state of the liquid detection sensor according to the second embodiment of the present invention when liquid is detected.

[0053] The liquid detection sensor according to the first embodiment is a water detection sensor, and 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, and therefore the resin bag 31 containing the electrolyte component 30 is made of a resin that is soluble or dispersible in oil.

[0054] Thus, 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 forming the resin bag. In other words, the liquid detection sensor of the present invention is highly versatile in that it can appropriately change the type of liquid to be detected.

[0055] As shown in Figure 3, in the metal-air battery 10, the electrolyte component 30 is placed between the positive electrode 11 and the negative electrode 12. The electrolyte component 30 is sealed inside a resin bag 31. There are multiple resin bags 31 in which the electrolyte component 30 is sealed, and the electrolyte component 30 is divided into multiple portions and sealed inside each resin bag 31. Furthermore, the resin bags 31 in which the electrolyte component 30 is sealed are supported throughout the porous structure of the separator 13, both on the surface and inside the separator 13.

[0056] The resin bag 31 is formed from an oil-soluble resin, for example, a resin that is soluble or dispersible in oil. Because the resin bag 31 is formed from an oil-soluble resin, the liquid detection sensor 2 functions as an oil detection sensor.

[0057] 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 copolymers; and hydrocarbon resins such as polyvinyl isobutyl ether and polyisobutylene. These compounds may be used individually or in combination of two or more.

[0058] The method for encapsulating the electrolyte components 30 in the resin bag is not particularly limited. Examples include a method in which the electrolyte components 20 are placed into the resin bag through the opening of the resin bag, and then the opening of the resin bag is sealed by bonding and heat welding. Another method is to encapsulate the components using a microcapsule manufacturing method using W / O dispersion or O / W dispersion. Furthermore, the method for supporting multiple resin bags 31 containing the electrolyte components 30 on the separator 13 is not particularly limited. Examples include a method in which the resin bags 21 are pressed into the voids of the separator 13. Another method is to disperse the resin bags 21 in a dispersion medium such as a solvent, then impregnate the separator 13 with the dispersion medium and dry and remove it. Finally, the separator 13 is divided into multiple parts, the resin bags 21 are placed between them, and then the separator 13 is bonded together.

[0059] The oil detected by the liquid detection sensor 2 is not a component of the electrolyte of the metal-air battery 10. Therefore, the resin bag 31, which is made of an oil-soluble resin, contains an electrolyte as an electrolyte component 30. Examples of the electrolyte component 30 include water containing an alkali metal salt such as sodium chloride or potassium chloride (an aqueous solution of an alkali metal salt), or water.

[0060] Next, the detection operation when the liquid detection sensor 2 detects oil, which is the target of detection, will be explained. As shown in Figure 4, when the oil 120, which is the target of detection, comes into contact with the metal-air battery 10 of the liquid detection sensor 2, it comes into contact with the peripheral edge 14 of the separator 13 and then permeates throughout the entire separator 13. As the oil 120 permeates throughout the entire separator 13, the resin bag 31, which is made of a resin that is soluble or dispersible with respect to the oil 120, dissolves or disperses. In other words, the resin bag 31 is destroyed by the oil 120, which is the target of detection. When the resin bag 31 dissolves or disperses, the electrolyte components 30 (for example, an aqueous solution of an alkali metal salt) that were sealed inside the resin bag 31 are released into the oil 120. The electrolyte components 30 released into the oil 120 act as an electrolyte, so the metal-air battery 10 discharges. When the metal-air battery 10 discharges, an aqueous solution of alkali metal salt is released from the resin bag 31 as the electrolyte. The ionic conductivity between the positive electrode 11 and the negative electrode 12 is improved by the action of the electrolyte components 30, thereby improving the power generation performance of the metal-air battery 10.

[0061] In the liquid detection sensor 2, the electrolyte components 30 of the metal-air battery 10, which is the power source, are sealed inside a resin bag 31 that is soluble in or dispersible with respect to the oil 120 to be detected, thus enabling its use in detecting oil. Furthermore, in the liquid detection sensor 2, because the electrolyte components 30 of the metal-air battery 10 are sealed inside the resin bag 31, the metal-air battery 10 can be prevented from degrading due to the electrolyte components 30 even if the liquid detection sensor 2 is installed for a long period of time, thereby improving detection accuracy.

[0062] Next, a liquid detection sensor according to the third embodiment of the present invention will be described. Since the main parts of the liquid detection sensor according to the third embodiment are common to those of the liquid detection sensors according to the first and second embodiments, the same reference numerals will be used to describe the same components as those in the liquid detection sensors according to the first and second embodiments. Figure 5 is a side view illustrating the overview of the liquid detection sensor according to the third embodiment of the present invention.

[0063] In the liquid detection sensors according to the first and second embodiments described above, a plurality of resin bags containing electrolyte components were dispersed throughout the separator and supported on the surface and inside the separator. Instead, as shown in Figure 5, in the liquid detection sensor 3 according to the third embodiment, a resin bag 41 containing electrolyte components 40 is sandwiched between the positive electrode 11 or the negative electrode 12 and the separator 13. That is, the resin bag 41 containing the electrolyte components 40 is interposed between the positive electrode 11 or the negative electrode 12 and the separator 13. The resin bag 41 containing the electrolyte components 40 may be interposed between the positive electrode 11 and the separator 13, or between the negative electrode 12 and the separator 13. Note that in Figure 5, the resin bag 41 containing the electrolyte components 40 is interposed between the positive electrode 11 and the separator 13.

[0064] In the liquid detection sensor 3, one or more resin bags 41 containing the electrolyte components 40 are provided between the electrode (positive electrode 11 in Figure 5) and the separator 13. The number of resin bags 41 may be one or more, but from the viewpoint of ease of installation and fixing stability, one resin bag 41 is preferred. In Figure 5, one resin bag 41 is provided. Therefore, in the liquid detection sensor 3 of Figure 5, the electrolyte components 40 are sealed in the resin bag 41 in a single, consolidated state. Furthermore, the resin bag 41 containing the electrolyte components 40 is provided over substantially the entire surface of the separator 13.

[0065] When the liquid detection sensor 3 is used as a water detection sensor, the resin bag 41 is made of a water-soluble resin. The electrolyte components 40 enclosed in the resin bag 41 include, for example, alkali metal salts such as sodium chloride and potassium chloride, or aqueous solutions of the alkali metal salts.

[0066] When the liquid detection sensor 3 is used as an oil detection sensor, the resin bag 41 is made of an oil-soluble resin. The electrolyte component 40 enclosed in the resin bag 41 may be, for example, water containing an alkali metal salt such as sodium chloride or potassium chloride (an aqueous solution of an alkali metal salt), or water.

[0067] In the liquid detection sensor 3, because the electrolyte components 40 of the metal-air battery 10 are sealed inside the resin bag 41, the metal-air battery 10 can be prevented from degrading due to the electrolyte components 40 even if the liquid detection sensor 3 is installed for a long period of time, and the detection accuracy is improved. Furthermore, in the liquid detection sensor 3, because the electrolyte components 40 of the metal-air battery 10 are sealed inside the resin bag 41, it is possible to use an electrolyte component 40 that imparts excellent power generation performance to the metal-air battery 10 while preventing degradation of the metal-air battery 10, so that the metal-air battery 10 can exhibit excellent power generation performance.

[0068] Next, an example of how to use the liquid detection sensor of the present invention will be described. For the sake of explanation, an 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. Figure 6 is an explanatory diagram of an example of how to use the liquid detection sensor of the present invention.

[0069] As shown in Figure 6, the notification unit 100, connected to the metal-air battery 10 via the wire section 101, uses, for example, a transmitting unit that activates its transmission function to the receiving unit 200 when it receives power generated from the metal-air battery 10. When the metal-air battery 10 detects the liquid to be detected (water 110 in Figure 6) and generates power, the notification unit 100 activates its transmission function by receiving power from the metal-air battery 10 and transmits a detection signal to the receiving unit 200. Examples of the transmitting unit include a wireless transmitting unit and a wired transmitting unit. In Figure 6, a wireless transmitting unit is used as the notification unit 100, enabling wireless transmission of the detection signal from the notification unit 100 to the receiving unit 200. Existing wireless methods such as wireless LAN, Bluetooth®, and Wi-Fi can be used for wireless communication.

[0070] When the receiving unit 200 receives a detection signal from the notification unit 100 of the liquid detection sensor 1, it detects that a leak or other incident (water leak or flooding in Figure 6) of the target liquid has occurred, notifies people that a water leak or flooding has occurred, and automatically shuts down the device or other equipment as necessary.

[0071] Next, other embodiments of the liquid detection sensor of the present invention will be described. In the liquid detection sensor according to the first and second embodiments described above, examples of methods for supporting a plurality of resin bags containing electrolyte components on a separator include a method of press-fitting the resin bags into the voids of the separator, a method of dispersing the resin bags in a dispersion medium such as a solvent and then impregnating the separator with the dispersion medium and drying it off, and a method of dividing the separator into multiple parts, arranging the resin bags between them, and then bonding the separator together. Alternatively, the resin bags may be supported and bonded to the separator by applying a material containing the resin bags to the surface of the separator and then drying the material. In this embodiment, the resin bags are mainly supported and bonded to the surface of the separator. Furthermore, a binder, an organic solvent, or other dispersion medium may be added to the material containing the resin bags as needed to improve the coatability on the separator surface. Since a material containing a resin bag becomes paste-like when it contains a binder, an organic solvent, or other dispersion medium, it is possible to impart excellent coating properties to the material containing the resin bag.

[0072] Examples of binders include acrylic polymers, polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene copolymer (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), ethylene chlorotrifluoroethylene copolymer (ECTFE), perfluoroalkoxyalkane (PFA), and perfluoroethylenepropene copolymer (FEP). Examples of dispersion media include alcohol compounds such as ethylene glycol, propylene glycol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, and diethylene glycol, as well as organic solvents such as N-methylpyrrolidone.

[0073] Furthermore, in order to position the resin bag between the positive and negative electrodes, in the liquid detection sensors according to the first and second embodiments described above, the resin bag containing the electrolyte components was supported on a separator, and in the liquid detection sensor according to the third embodiment, the resin bag was sandwiched between the positive or negative electrode and the separator. Alternatively, the resin bag may be supported and adhered to the positive electrode surface facing the negative electrode by applying a material containing the resin bag to the positive electrode surface facing the negative electrode, and then drying the material. By supporting and adhering the resin bag to the positive electrode surface facing the negative electrode, the resin bag is positioned between the positive and negative electrodes. More specifically, if a separator is provided between the positive and negative electrodes, the resin bag is positioned between the positive electrode and the separator.

[0074] Furthermore, materials containing resin bags may, if necessary, be supplemented with binders, organic solvents, or other dispersion media to improve coating properties on the positive electrode surface. Examples of binders include acrylic polymers, polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene copolymer (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), ethylene chlorotrifluoroethylene copolymer (ECTFE), perfluoroalkoxyalkane (PFA), and perfluoroethylenepropene copolymer (FEP). Examples of dispersion media include alcohol compounds such as ethylene glycol, propylene glycol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, and diethylene glycol, and organic solvents such as N-methylpyrrolidone.

[0075] Furthermore, in the liquid detection sensor according to the first embodiment, the resin bag was made of a water-soluble resin, and in the liquid detection sensor according to the second embodiment, the resin bag was made of an oil-soluble resin. However, instead, a single metal-air battery may use both a resin bag made of a water-soluble resin and a resin bag made of an oil-soluble resin. By using both a resin bag made of a water-soluble resin and a resin bag made of an oil-soluble resin, a single liquid detection sensor can handle both water detection and oil detection. In addition, in the liquid detection sensors according to the first to third embodiments, a separator was provided between the positive and negative electrodes. However, if a short circuit can be prevented by contact between the positive and negative electrodes, a separator is not necessary. Moreover, any support member that supports the positive and negative electrodes at a predetermined distance from each other may be used instead of a separator.

[0076] Furthermore, in the liquid detection sensor according to the third embodiment, a resin bag was sandwiched between one electrode (positive electrode) and the separator, but instead, resin bags may be sandwiched between the positive electrode and the separator, and between the negative electrode and the separator, respectively. Also, in the liquid detection sensor according to the third embodiment, one resin bag was sandwiched between one electrode and the separator, but instead, multiple resin bags may be sandwiched between one electrode and the separator.

[0077] Furthermore, in the above example of how to use the liquid detection sensor, the notification unit was a transmitter unit that has a function to transmit to the receiver unit, but instead, it may be a liquid detection display unit that receives power from a metal-air battery to notify a person of liquid detection. Examples of display means for the liquid detection display unit include lighting a warning light and emitting a warning sound. [Industrial applicability]

[0078] The liquid detection sensor of the present invention is versatile, can prevent deterioration of the metal-air battery that serves as the power source even after long-term installation, and the metal-air battery exhibits excellent power generation performance. Therefore, it can be used in a wide range of liquid detection fields, such as detecting water leaks and roof leaks in buildings, water leaks and oil leaks in various facilities and factories, flooding in roads and underground facilities, detection of dangerous water levels by detecting water levels in rivers and lakes, detection of blood leaks and drug leaks in medical settings, and detection of urination in nursing care settings. [Explanation of Symbols]

[0079] 1, 2, 3 Liquid detection sensors 10 Metal-air batteries 11 Positive electrode 12 Negative electrode 13 Separator 20, 30, 40 Electrolyte components 21, 31, 41 Resin bags 100 Hochi Department

Claims

1. A metal-air battery comprising a positive electrode, a negative electrode, and an electrolyte component located between the positive electrode and the negative electrode, Further, a support member is provided between the positive electrode and the negative electrode, having an air gap, and supporting the positive electrode and the negative electrode. The electrolyte components are sealed inside a resin bag, and the resin of the resin bag has solubility or dispersibility in the liquid to be detected. There are multiple resin bags in which the electrolyte components are enclosed. The electrolyte components are divided into multiple parts and sealed inside each of the resin bags, and A liquid detection sensor in which the resin bag is introduced into the gap portion of the support member.

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. The liquid detection sensor according to claim 1 or 2, wherein the resin bag containing the electrolyte components is supported on the support member.

4. The liquid detection sensor according to any one of claims 1 to 3, wherein the resin bag containing the electrolyte components is disposed between the positive electrode and the negative electrode.

5. The liquid detection sensor according to claim 1 or 2, wherein the resin bag containing the electrolyte components is disposed between the support member and the positive electrode and / or between the support member and the negative electrode.

6. The liquid detection sensor according to any one of claims 1 to 5, wherein the electrolyte component comprises water, an alkali metal salt, or an aqueous solution of an alkali metal salt.

7. The liquid detection sensor according to any one of claims 1 to 6, wherein the active material of the negative electrode includes at least one metal selected from the group consisting of magnesium (Mg), aluminum (Al), lithium (Li), calcium (Ca), and zinc (Zn).

8. A liquid detection sensor according to any one of claims 1 to 7, further comprising a notification unit that receives power from the metal-air battery and notifies of liquid detection.

9. The liquid detection sensor according to any one of claims 1 to 7, further comprising a notification unit capable of wirelessly transmitting the detection signal of the metal-air battery to a receiving unit.

10. A liquid detection sensor according to any one of claims 1 to 9, which is a water detection sensor.

11. A liquid detection sensor according to any one of claims 1 to 9, which is an oil detection sensor.

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