JP7437846B2 - liquid detection sensor - Google Patents

Description

The present invention relates to a liquid detection sensor equipped with a metal-air battery.

Liquid leak detection systems are used at indoor work sites. In the liquid leakage detection system, a liquid detection sensor is placed at the location of the liquid leakage. The liquid detection sensor detects a liquid leak by detecting electrical changes when it comes into contact with liquid from the outside.

For example, in the invention described in Patent Document 1, when a liquid leaks near a liquid detection sensor, the liquid is conveyed to the liquid detection sensor through a liquid guide path, and the liquid is detected.

Japanese Patent Application Publication No. 2006-133075 International Publication No. 2012/020507 Japanese Patent Application Publication No. 2017-148332

However, the inventions described in these patent documents have a problem in that they cannot appropriately distinguish between dew condensation and water leakage.

The present invention has been made in view of these points, and an object of the present invention is to provide a liquid detection sensor that does not detect minute amounts of liquid such as dew condensation and can suppress false detection.

The liquid detection sensor according to the present invention includes a positive electrode sheet and a negative electrode sheet, and includes a metal air battery that generates electricity when liquid permeates between the positive electrode sheet and the negative electrode sheet, and a metal air battery that encloses the metal air battery. , a flexible member having an opening , the flexible member being a heat-shrinkable body, a separator interposed between the positive electrode sheet and the negative electrode sheet, and the separator is provided with a liquid contact area exposed from the opening, and the opening is expanded to accommodate the positive electrode sheet, the separator, and the negative electrode sheet in the heat shrinkable body, and the heat shrinkable body is in close contact with the metal-air battery except for the liquid contact area, so that the metal-air battery is wrapped .
The liquid detection sensor according to the present invention includes a positive electrode sheet and a negative electrode sheet, and includes a metal air battery that generates electricity when liquid permeates between the positive electrode sheet and the negative electrode sheet, and a metal air battery that encloses the metal air battery. , a flexible member having an opening, the flexible member being a heat-shrinkable body, a separator interposed between the positive electrode sheet and the negative electrode sheet, and the separator is provided with a liquid contact area exposed from the opening, the positive electrode sheet and the negative electrode sheet are smaller than the separator, and one of the positive electrode sheet and the negative electrode sheet is smaller than the other. The one sheet is formed to be smaller than the other sheet, and the one sheet is arranged farther from the opening than the other sheet .

In the present invention, it is preferable that the separator has a structure in which a plurality of separator sheets are laminated.

According to the liquid detection sensor of the present invention, a metal-air battery is wrapped in a flexible member, and liquid is absorbed into the metal-air battery through an opening provided in the flexible member. Therefore, it is possible to control a small amount of liquid equivalent to condensation so that it does not penetrate into the metal-air battery, and it is possible to detect the liquid to appropriately distinguish between dew condensation and water leakage.

FIG. 1A is an exploded plan view of a metal-air battery that constitutes a liquid detection sensor in this embodiment, FIG. 1B is a plan view of a liquid detection sensor in this embodiment, and FIG. 1C is an exploded plan view of a metal air battery that constitutes a liquid detection sensor in this embodiment. It is a sectional view of the liquid detection sensor in this embodiment. FIG. 2 is a block diagram of a liquid detection device including a liquid detection sensor according to this embodiment.

Hereinafter, one embodiment of the present invention (hereinafter abbreviated as "embodiment") will be described in detail. Note that the present invention is not limited to the following embodiments, and can be implemented with various modifications within the scope of the gist.

The liquid detection sensor 1 in this embodiment includes a metal air battery 2 and a flexible member 9 that encloses the metal air battery 2. As shown in FIG. 2, the liquid detection sensor 1 further includes a transmitter 8.

As shown in FIG. 1A, the metal-air battery 2 includes, for example, a circular negative electrode sheet (metal electrode sheet) 3, a circular separator 4, and a circular positive electrode sheet (air electrode sheet) 5. It has a laminate structure. As shown in FIGS. 1A and 1C, the separator 4 is interposed between the negative electrode sheet 3 and the positive electrode sheet 5. Note that the shapes of the negative electrode sheet 3, separator 4, and positive electrode sheet 5 are not limited to a circular shape, and can be selected from various shapes such as an elliptical shape and a rectangular shape depending on the intended use.

As shown in FIGS. 1A and 1C, the metal-air battery 2 of this embodiment has a structure in which the separator 4 is a stack of a plurality of circular separator sheets 6. Depending on the number of separator sheets 6 stacked, the distance between the negative electrode sheet 3 and the positive electrode sheet 5 can be adjusted appropriately. Note that in this embodiment, the number of separator sheets 6 is not limited to a plurality, and may be a single number.

Although not limited to this, each sheet can be fixed via an adhesive layer. At this time, it is preferable that the adhesive layer is partially provided on the edges of the negative electrode sheet 3 and the positive electrode sheet 5, and not provided on the detection area 4'' of the separator 4. Here, the detection region 4'' refers to a region where the negative electrode sheet 3 and the positive electrode sheet 5 overlap with the separator 4 in between.

The metal constituting the negative electrode sheet 3 is preferably one of magnesium (Mg), Mg alloy, zinc (Zn), Zn alloy, aluminum (Al), or Al alloy. Among these, the metal constituting the negative electrode sheet 3 is more preferably Mg or an Mg alloy.

Each separator sheet 6 constituting the separator 4 is made of a material that is electrically insulating, ion permeable, and liquid permeable. For example, nonwoven fabrics, woven fabrics, porous thin films, etc.

The positive electrode sheet 5 includes a current collector and a catalyst layer (reaction part). The properties required of the current collector are conductivity to transfer electrons emitted from the negative electrode sheet 3 to the catalyst layer, and air permeability to allow oxygen to pass through. Although the structure of the current collector is not limited, for example, existing ones such as wire mesh or foam metal can be used. Further, the characteristics required of the catalyst layer are hydrophobicity that does not release liquid to the outside, and air permeability that allows oxygen to pass through. Existing materials can be used for the catalyst layer. The catalyst layer is formed on at least one surface of the current collector, and the catalyst layer is in close contact with the separator 4.

Note that, although not limited, the thickness of the positive electrode sheet 5 (including the current collector) is approximately 0.4 to 2.0 mm. Further, the thickness of the negative electrode sheet 3 is approximately 0.05 to 2.0 mm.

As shown in FIGS. 1A and 1C, the separator 4 is formed to be larger than the area where the positive electrode sheet 5 and the negative electrode sheet 3 overlap with the separator 4 in between. That is, each separator sheet 6 constituting the separator 4 is formed to have a larger area than the area overlapping with the positive electrode sheet 5 and the negative electrode sheet 3.

As shown in FIGS. 1A and 1C, the positive electrode sheet 5 is formed smaller than the negative electrode sheet 3. Each separator sheet 6 is formed somewhat larger than the negative electrode sheet 3. As a result, the separator 4 protrudes outside the outer peripheral end 5a of the positive electrode sheet 5. Further, by forming the separator 4 to be larger than the positive electrode sheet 5 and the negative electrode sheet 3, the positive electrode sheet 5 and the negative electrode sheet 3 can be appropriately aligned within the separator 4 in the vertical direction in the drawing. Therefore, the separator 4 can be appropriately interposed in the entire area between the positive electrode sheet 5 and the negative electrode sheet 3. In this way, the protrusion of the separator 4 allows the liquid to penetrate into the detection area 4'' to enable liquid detection, and also has a short-circuit prevention effect against a small amount of liquid such as dew condensation.

In this embodiment, the metal air battery 2 is wrapped in a flexible member 9. Any electrically insulating flexible material can be appropriately wrapped closely around the metal-air battery 2. In this embodiment, the material and form of the flexible member 9 are not limited, but examples thereof include a rubber tube, an insulating film, a heat shrinkable body, and the like. Furthermore, examples of the material of the flexible member 9 include polyester, polytetrafluoroethylene (PTFE), and the like. For example, when using a rubber tube as the flexible member 9, the rubber tube can be physically expanded and each electrode sheet and separator can be placed inside the rubber tube. Further, as the flexible member 9, a heat-shrinkable body can be preferably used. In this way, by using a heat-shrinkable body (especially a heat-shrinkable tube), if the metal-air battery 2 with a laminated structure is housed in the heat-shrinkable body and heated, the heat-shrinkable body will shrink, and the metal-air battery 2 will be heated. It is possible to complete the liquid detection sensor 1 in which the liquid detection sensor 1 is tightly wrapped in a heat-shrinkable body, and manufacturing can be facilitated.

As shown in FIGS. 1B and 1C, the flexible member 9 is provided with an opening 9a, through which a portion of the separator 4 is exposed to the outside. The separator 4 exposed from the opening 9a is a liquid contact area 4'.

When a liquid containing water contacts the liquid contact area 4' of the separator 4, the liquid permeates from the liquid contact area 4' to the detection area 4''. When the liquid reaches the detection region 4'', for example, when the metal constituting the negative electrode sheet 3 is Mg, the oxidation reaction shown in (1) below occurs on the negative electrode sheet 3 side. Further, in the positive electrode sheet 5, a reduction reaction shown in (2) below occurs. Therefore, in the metal-air battery 2 as a whole, the reaction shown in (3) below occurs, and power generation (discharge) is performed.
(1) 2Mg → 2Mg ²⁺ +4e ^-
(2) O ₂ +2H ₂ O+4e ^- →4OH ^-
(3) 2Mg+O ₂ +2H ₂ O → 2Mg(OH) ₂

In this embodiment, since most of the periphery of the metal-air battery 2 is surrounded by the flexible member 9, a small amount of liquid such as dew condensation tends to adhere to the surface of the flexible member 9. Furthermore, the separator 4 is contracted by the flexible member 9, so that a small amount of liquid is difficult to be absorbed into the metal-air battery 2. As a result, a small amount of liquid such as dew condensation does not cause the battery reaction described in (3) above, and no power is generated. On the other hand, when the amount of liquid is larger than that of dew condensation, for example, when there is a water leak, the liquid permeates from the liquid contact area 4' exposed through the opening 9a of the flexible member 9 to the detection area 4'', and the metal air The battery 2 generates electricity, and the liquid detection sensor 1 can detect water leakage. In this way, the liquid detection sensor 1 of this embodiment can detect liquid while appropriately distinguishing between dew condensation and water leakage. Thereby, it is possible to prevent the metal-air battery 2 from generating electricity and erroneously detecting it when dew condenses.

Furthermore, by covering the metal-air battery 2 with the flexible member 9, the negative electrode sheet 3, separator 4, and positive electrode sheet 5 that constitute the metal-air battery 2 can be appropriately held. Although each sheet may be joined with an adhesive, the flexible member 9 allows the sheets to be brought into close contact with each other without using an adhesive.

In this embodiment, it is preferable that the separator 4 has a structure in which a plurality of separator sheets 6 are laminated. As a result, even if a small amount of liquid, such as condensation, comes into contact with the liquid contact area 4', it can be more effectively prevented from penetrating into the detection area 4'', and more effectively distinguish between condensation and water leakage. This makes it possible to detect liquids.

Further, as shown in FIGS. 1A and 1C, the positive electrode sheet 5 and the negative electrode sheet 3 are formed to have a smaller area than the separator 4, so that they are exposed through the opening 9a of the flexible member 9 and are exposed to the outside. A liquid contact area 4' may be provided which extends in the direction. This allows leakage water to seep in from the liquid contact area 4', allowing the metal-air battery 2 to generate electricity appropriately. Furthermore, even if dew condensation adheres to the liquid contact area 4', the distance from the liquid contact area 4' to the detection area 4'' is far, and there is not enough liquid to penetrate into the detection area 4''. , the metal-air battery 2 does not generate electricity and does not detect liquid.

In this embodiment, the positive electrode sheet 5 is formed smaller than the negative electrode sheet 3; however, the negative electrode sheet 3 may be formed smaller than the positive electrode sheet 5, or both the positive electrode sheet 5 and the negative electrode sheet 3 may be formed to be the same size. It may be formed small.

In FIGS. 1B and 1C, an opening 9a is provided in a part of the side of the flexible member 9, but the location, number, shape, etc. of the opening 9a are not limited. The opening 9a may be arranged on the upper surface or the lower surface of the flexible member 9. However, in order to prevent detection of minute amounts of liquid such as dew condensation, an opening 9a is provided in a part of the vicinity of the outer peripheral end of the separator 4, and the outer peripheral end of the separator 4 exposed from the opening 9a is placed in the liquid contact area 4'. It is preferable that Moreover, the flexible member 9 may have a mesh structure.

In this embodiment, the metal-air battery 2 of the liquid detection sensor 1 generates electricity when it comes into contact with the liquid, and the wireless board can be activated with the electric power, and the contact with the liquid can be notified to the outside. As shown in FIG. 2, the liquid detection sensor 1 in this embodiment includes a metal air battery 2 and a transmitter 8. For example, the transmitter 8 is a wireless board. In this embodiment, wireless notification is possible, but it is also possible to provide the following functions in addition to that function. That is, in the metal-air battery 2, the voltage value (resistance value) changes due to a battery reaction based on liquid leakage. A detection signal based on this voltage change is wirelessly transmitted from the transmitter 8 to the receiver 9. Based on the received detection signal, the receiving section 9 can detect that a liquid leak has occurred, and can automatically stop the apparatus or the like or notify a person that a liquid leak has occurred. At this time, by using a threshold value for the detection signal, it is possible to determine that liquid leakage has occurred or to determine the level of liquid leakage when the level of the detection signal exceeds the threshold value. On the other hand, even if dew condensation occurs, the metal-air battery 2 does not react, and no voltage change occurs. Therefore, the detection signal is not transmitted from the transmitting section 8 to the receiving section 9, and false detection can be prevented.

In this embodiment, the liquid detection sensor 1 does not require an external power source and can wirelessly send a detection signal obtained by a metal-air battery from the transmitter 8 to the receiver 7. The wireless method is not limited, and existing methods such as wireless LAN, Bluetooth (registered trademark), Wi-Fi, etc. can be used.

Furthermore, although the metal-air battery 2 in this embodiment has a separator 4 between the negative electrode sheet 3 and the positive electrode sheet 5, it is also applicable to a configuration in which the separator 4 is not provided. That is, the metal-air battery 2 can be wrapped in the flexible member 9 in a configuration that allows liquid to penetrate between the negative electrode sheet 3 and the positive electrode sheet 5 without using the separator 4.

The liquid detection sensor 1 of this embodiment self-generates electricity upon contact with a liquid, but in order to self-generate electricity in this manner, it is desirable, although not necessarily necessary, for salt to be present in the liquid. Examples of salts include, but are not limited to, sodium chloride. Therefore, if the liquid is a component that does not contain salt, it is preferable that the separator contains salt.

Although the usage of the liquid detection sensor 1 of this embodiment is not limited, it can be applied to indoor work sites and the like.

According to the liquid detection sensor of the present invention, it can be effectively applied as a water leakage detection sensor. In particular, according to the present invention, measures against condensation can be realized without requiring an external power source. Therefore, it is easy to use and can be used easily regardless of the object or location.

1: Liquid detection sensor 2: Metal air battery 3: Negative electrode sheet 4: Separator 4': Liquid contact area 4'': Detection area 5: Positive electrode sheet 5a: Outer peripheral end 6: Separator sheet 7: Receiving section 8: Transmitting section 9: Flexible member 9a: Opening

Claims (3)

A metal-air battery that has a positive electrode sheet and a negative electrode sheet, and generates electricity by liquid permeating between the positive electrode sheet and the negative electrode sheet,
a flexible member that encloses the metal air battery and has an opening;
The flexible member is a heat-shrinkable member,
A separator is interposed between the positive electrode sheet and the negative electrode sheet, and the separator is provided with a liquid contact area exposed from the opening,
The opening is widened to accommodate the positive electrode sheet, the separator, and the negative electrode sheet in the heat-shrinkable body, and the heat-shrinkable body is in close contact with the metal-air battery except for the liquid contact area, and the metal-air battery is A liquid detection sensor characterized in that an air battery is wrapped . A metal-air battery that has a positive electrode sheet and a negative electrode sheet, and generates electricity by liquid permeating between the positive electrode sheet and the negative electrode sheet,
a flexible member that encloses the metal air battery and has an opening;
The flexible member is a heat-shrinkable member,
A separator is interposed between the positive electrode sheet and the negative electrode sheet, and the separator is provided with a liquid contact area exposed from the opening,
The positive electrode sheet and the negative electrode sheet are smaller than the separator, and one of the positive electrode sheet and the negative electrode sheet is smaller than the other sheet,
The liquid detection sensor is characterized in that the one sheet is arranged farther from the opening than the other sheet . 3. The liquid detection sensor according to claim 1 , wherein the separator has a structure in which a plurality of separator sheets are laminated.

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