JP2023062207A - Laminate sheet - Google Patents

Abstract

To provide a laminate sheet for a liquid detection sensor that can make it easier to perform processing according to the shape and size of an installation position.SOLUTION: The laminate sheet includes: a first electrode layer; a second electrode layer; an insulating layer between the first electrode layer and the second electrode layer; a plurality of openings penetrating the first electrode layer and the insulating layer, the opening making the second electrode exposed; and a detector for detecting liquid. The laminate sheet further includes a plurality of repetitive units having the openings, and the repetitive units are arranged in vertical lines and in horizontal lines, each line having more than one repetitive unit.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a laminated sheet, and more specifically to a laminated sheet used as a detection sensor portion of a liquid detection sensor.

Conventionally, liquid detection sensors are used in various products to detect liquid leakage. For example, liquid detection sensors are used to detect leakage of cooling water for servers and cooling water for batteries in electric vehicles.

The liquid detection sensor has a first electrode layer, a second electrode layer, and an insulating layer disposed between the first electrode layer and the second electrode layer, a laminated sheet constituting a detection unit for detecting a liquid, in which a plurality of openings are formed to penetrate the electrode layer and the insulating layer and expose the second electrode layer, and the first electrode layer and the It is known to have an electric wire connected to each of the second electrode layers. According to this liquid detection sensor, the first electrode layer and the second electrode layer are electrically connected by the liquid that has entered the opening, whereby the liquid is detected.

Further, Patent Document 1 describes, as the lamination sheet, a belt-shaped lamination sheet having a plurality of repeating units each having a plurality of openings, and in which the plurality of repeating units are arranged in the horizontal direction. According to such a laminated sheet, it is possible to use a sheet piece cut out as much as necessary according to the length of the installation location as the detection portion of the liquid detection sensor.

Japanese Patent Application Laid-Open No. 2019-109110

However, since the laminated sheet described in Patent Document 1 has a band shape in which the repeating units are connected in a line, it has a problem that it is difficult to flexibly process the sheet piece according to the shape and size of the installation location. In particular, recently, products that use liquid detection sensors are becoming more popular, and it is said that it is difficult to process a sheet piece according to the shape and size of the installation location of such a product with the above laminated sheet. There is a problem.

In view of the above problems, an object of the present invention is to provide a laminated sheet for a liquid detection sensor that can be relatively easily processed according to the shape and size of the installation location.

The laminated sheet according to the present invention is
a first electrode layer, a second electrode layer, and an insulating layer disposed between the first electrode layer and the second electrode layer, wherein the first electrode layer and the insulating layer A laminated sheet having a plurality of openings that penetrate through and expose the second electrode layer, and constitutes a detection unit for detecting liquid,
A plurality of repeating units having a plurality of openings are provided, and a plurality of the repeating units are arranged in the vertical direction and the horizontal direction.

According to such a configuration, since a plurality of repeating units are arranged in the vertical direction and the horizontal direction, it becomes easier to process the sheet piece according to the shape and size of the installation location compared to the conventional technology.

In addition, the laminated sheet is preferably
The repeating unit is formed in a rectangular shape and has a vertical dimension to a horizontal dimension ratio of 3:1 to 1:3.

According to such a configuration, the ratio of the vertical dimension to the horizontal dimension of the repeating unit is 3:1 to 1:3, so that the sheet piece can be processed according to the shape and size of the installation location. It can get easier.

The laminated sheet is preferably
The first electrode layer of the repeating unit has a conductive portion made of a conductive material and an opening formed with the opening but not provided with the conductive material,
The conductive portion includes a wire connection portion that is wider than a circular area with a diameter of 4.0 mm.

According to such a configuration, the conductive portion includes a wire connection portion wider than a circular area with a diameter of 4.0 mm. It becomes easy to connect the electric wire by

The laminated sheet is preferably
wherein the plurality of openings of the repeating unit includes a connection opening for connecting an electric wire to the exposed surface of the second electrode layer;
The wire connection portions and the connection openings are aligned vertically or horizontally in the repeating unit.

According to such a configuration, since the wire connecting portion and the connection opening are arranged in the vertical direction or the horizontal direction in the repeating unit, regardless of the shape and size of the sheet piece cut from the laminated sheet, the first electrode layer And the connection of electric wires to the second electrode layer is facilitated.

As described above, according to the present invention, it is possible to provide a laminated sheet for a liquid detection sensor that can be relatively easily processed according to the shape and size of the installation location.

FIG. 1 is a perspective view of a laminated sheet according to one embodiment. 2 is a plan view of the laminated sheet of FIG. 1. FIG. 3 is a bottom view of the laminated sheet of FIG. 1. FIG. 4 is a front view of the laminated sheet of FIG. 1. FIG. 5 is a left side view of the laminated sheet of FIG. 1; 6 is a right side view of the laminated sheet of FIG. 1; FIG. 7 is a cross-sectional view taken along line VII-VII of FIG. 2. FIG. FIG. 8 is a perspective view of a liquid detection sensor provided with a sheet piece cut out from the laminated sheet of FIG. 1 as a detection part. FIG. 9 is a perspective view of a terminal as a connecting material configured to sandwich a laminated sheet. FIG. 10 is a plan view of a repeating unit, showing a modification of the repeating unit. FIG. 11 is a plan view of the repeating unit, showing a modification of the repeating unit. FIG. 12 is a plan view of the repeating unit, showing a modification of the repeating unit. FIG. 13 is a diagram showing a half unit.

Hereinafter, a laminated sheet according to one embodiment of the present invention will be described with reference to the drawings.

The laminated sheet 1 of the present embodiment is used as a detection portion of a liquid detection sensor 100, and as illustrated in FIG. Thus, the liquid detection sensor 100 is configured.

As shown in FIGS. 1 to 7, the laminated sheet 1 is arranged between the first electrode layer 10, the second electrode layer 20, and the first electrode layer 10 and the second electrode layer 20. A plurality of openings 40 are formed through the first electrode layer 10 and the insulating layer 30 to expose the second electrode layer 20 . As shown in FIG. 8, in this embodiment, the first electrode layer 10 is arranged on the outermost side, and one of the pair of electric wires 3 is electrically connected to the surface thereof. More specifically, the first electrode layer 10 has a conductive portion 11 made of a conductive material and an opening 12 in which an opening 40 is formed and the conductive material is not provided. , the electric wire 3 is electrically connected to the conductive portion 11 . The second electrode layer 20 also has an exposed surface 21 exposed from the opening 40 , and the other of the pair of electric wires 3 is electrically connected to the exposed surface 21 .

In this embodiment, as shown in FIG. 2, the laminated sheet 1 is formed in a rectangular shape when viewed from the first electrode layer 10 side (in plan view). Therefore, hereinafter, the lateral direction of the laminated sheet 1 may be referred to as the longitudinal direction, and the longitudinal direction of the laminated sheet 1 may be referred to as the lateral direction. Further, of the laminated sheet 1, the surface on the opening side of the opening 40 may be called the front surface, and the surface opposite to the front surface may be called the back surface.

The conductive portion 11 of the first electrode layer 10 and the second electrode layer are connected without interruption so that the liquid can be detected at all positions on the surface of the laminated sheet 1 . Therefore, it is preferable that each of the first electrode layer 10 and the second electrode layer 20 is made of one conductive sheet.

The laminated sheet 1 and the electric wire 3 are electrically connected by a connecting member 6 made of a conductive material. Solder 6a is preferable as the connecting material 6 in terms of cost. Alternatively, the connection member 6 may be a terminal 6b connected to both connection ends of the electric wire 3. FIG. Moreover, as shown in FIG. 9, the terminals 6b are preferably configured so as to sandwich the laminated sheet 1 therebetween. More specifically, the terminal 6b includes a sandwiching body 60 for sandwiching the laminated sheet 1. Inside the sandwiching body 60, a first conductive portion 61 and a first conductive portion 61 that can come into contact with the first electrode layer 10 are provided. It has a second conductive portion 62 that can come into contact with the two electrode layers 20 , and the first conductive portion 61 is formed in a size that does not enter the first opening 41 , thereby providing a second conductive portion 62 . is configured so as not to contact with the electrode layer 20 of the .

With the configuration as described above, in the liquid detection sensor 100, the first electrode layer 10 and the second electrode layer 20 are electrically connected by the liquid that has entered the opening 40, and accordingly the conduction state between the electrode layers changes. By doing so, the presence of liquid is detected.

The liquid detection sensor 100 normally has an insulation resistance of 1 MΩ or more, preferably 10 MΩ or more, when no liquid has entered the opening 40 . As a result, erroneous detection due to temperature and humidity changes in the installation environment is suppressed.

The liquid that can be detected by the liquid detection sensor 100 is assumed to be a conductive liquid that makes each electrode layer conductive, such as a liquid containing water. Also, the liquid may be acidic or basic.

The laminated sheet 1 has a plurality of repeating units 50 each having a plurality of openings 40, and the repeating units 50 are arranged vertically and horizontally. In the laminated sheet 1, the repeating units 50 are arranged continuously without gaps. As shown in FIG. 2, the repeating unit 50 of the present embodiment is formed in a rectangular shape when viewed from the side of the first electrode layer 10 (in plan view), and has a plurality of openings 40 inside. formed. In the laminated sheet 1, the repeating units 50 are preferably arranged vertically by two or more and horizontally by three or more, and may be vertically arranged by three or more and horizontally by four or more. more preferred. In the laminated sheet 1 of this embodiment, three repeating units 50 are arranged in the vertical direction and eight each in the horizontal direction.

The repeating unit 50 is formed with a longitudinal dimension of typically 15-30 mm and a transverse dimension of typically 5-270 mm. Also, the repeating unit 50 is preferably formed so that the ratio of the vertical dimension to the horizontal dimension is 3:1 to 1:3. This facilitates processing of the sheet piece 2 according to the shape and size of the installation location.

The repeating unit 50 includes, as the plurality of openings 40, a plurality of first openings 41 formed so as to be scattered, and a connection opening for connecting the electric wire 3 to the exposed surface 21 of the second electrode layer 20. and a plurality of second openings 42 . The second opening 42 is formed larger than the first opening 41 , thereby facilitating connection of the wire 3 to the exposed surface 21 .

The first opening 41 may have a size that allows liquid to enter inside, and is usually formed in a circular shape with a diameter of 2.0 mm or more.

The second opening 42 is formed such that the exposed surface 21 of the second electrode layer 20 is wider than a circle with a diameter of 7.0 mm. This facilitates the connection of the wires 3 to the second electrode layer 20, especially by soldering. The second opening 42 of this embodiment is formed in a rectangular shape with rounded corners.

In the repeating unit 50 , the shortest distance between the opening edges of the adjacent openings 40 is preferably 2.5 mm or less, more preferably 2.0 mm or less, from the viewpoint of increasing the detection accuracy of the liquid detection sensor 100 .

The conductive portion 11 of the first electrode layer 10 in the repeating unit 50 has a plurality of wire connection portions 51 for connecting the wires 3, which wire connection portions 51 are wider than the circular region 510 with a diameter of 4.0 mm. include. In other words, the opening 40 is not formed in the circular region 510 or the wire connecting portion 51 . The diameter of the circular region 510 is more preferably 5.0 mm wider than the circular region 510 , and more preferably 6.0 mm wider than the circular region 510 . . Also, the diameter of the circular region 510 included in the wire connecting portion is preferably 21.0 mm or less. When the electric wire 3 is connected to the first electrode layer 10, it is preferable that the electric wire 3 is connected so that the connecting material 6 fits within the wire connection portion 51, and the connecting material 6 fits within the circle region 510. An electric wire 3 is preferably connected. From the viewpoint that the liquid detection sensor 100 can be incorporated into various products at relatively low cost, soldering is preferable as a method for connecting the electric wires 3 to the respective electrode layers. When soldering is adopted as the method for connecting the electric wire 3, if the repeating unit 50 is not provided with the electric wire connection portion 51, the solder protrudes from the conductive portion 11 and easily enters the opening 40. Connection of wires 3 to layer 10 becomes difficult. On the other hand, the configuration in which the wire connecting portion 51 is provided facilitates connection of the wire 3 to the first electrode layer 10 by soldering.

Further, if the repeating unit 50 is not provided with the wire connecting portion 51, the surface of the first electrode layer 10 is pressed against the connecting member 6 when the connecting member 6 is the terminal 6b as shown in FIG. As a result, the laminated sheet 1 may be deformed. More specifically, there is a possibility that the thickness of the laminated sheet 1 may be reduced or the first opening 41 may be enlarged at the portion where such pressure is applied. There is a risk of contact with the second electrode layer 20 through one opening 41, resulting in erroneous detection. In contrast, if the wire connecting portion 51 is provided, such erroneous detection can be suppressed.

In the repeating unit 50, the second opening 42 and the wire connecting portion 51 are preferably arranged so as to have a point-symmetrical relationship. In such a configuration, the second opening 42 and the wire connecting portion 51 are arranged vertically and horizontally. As a result, when a pair of electric wires 3 are connected to the repeating unit 50, both connecting ends of the electric wires 3 can be connected from any of the four directions (directions corresponding to the edges of the repeating unit 50). can be aligned and connected, it becomes easy to flexibly install the liquid detection sensor 100 according to the shape and size of the installation location.

Moreover, in the repeating unit 50, the plurality of openings 40 may be arranged so as to have a point-symmetrical relationship. Also in such a configuration, the second opening 42 and the wire connecting portion 51 are arranged vertically and horizontally. As a result, when a pair of electric wires 3 are connected to the repeating unit 50, it is possible to align both connection ends of the electric wires 3 and connect them from any of the four directions. Flexible installation of the liquid detection sensor 100 according to the shape and size of the location is facilitated.

In addition, in the repeating unit 50, when the plurality of openings 40 are arranged so as to have a point-symmetrical relationship, the repeating unit 50 is arranged so as to divide the repeating unit 50 into two equal parts in the vertical direction or the horizontal direction, as shown in FIG. It will have two half-units 52 defined by the dividing bisector. In this case, a plurality of first openings 41 may be arranged on the bisector. This facilitates cutting the laminated sheet 1 along the bisector.

Moreover, it is preferable that a plurality of first openings 41 are formed along either edge, opposing edge, or all edges of the repeating unit 50 . As a result, the portion between the adjacent repeating units 50 and extending between the plurality of first openings 41 serves as a reference for cutting the adjacent repeating units 50, so that the sheet piece 2 can be processed. becomes easier. Furthermore, a plurality of first openings 41 may be formed on the boundary line between adjacent repeating units 50 .

The laminated sheet 1 having the above structure facilitates processing of the sheet piece 2 according to the shape and size of the installation location. For example, the sheet piece 2 cut from the laminated sheet 1 may be processed into a rectangular shape, as illustrated in FIG. 8, and both the longitudinal and lateral lengths may be adjusted. . Moreover, the sheet piece 2 may be processed so as to have one or more bends such as an L-shape or a U-shape.
Further, when processing the sheet piece 2 , the sheet piece 2 may be cut from the laminated sheet 1 along the bisector that bisects the repeating unit 50 in the vertical direction or the horizontal direction. That is, the laminated sheet 1 may be cut so that the half unit 52 is arranged on the outer peripheral portion of the sheet piece 2 .
Thus, according to the laminated sheet 1, the arrangement pattern of the repeating units 50 of the sheet piece 2 can have a relatively large number of variations.

Next, each layer constituting the laminated sheet 1 will be described.

Each of the first electrode layer 10 and the second electrode layer 20 is formed of one sheet of metal foil coated with carbon. Examples of metal foil include copper foil and aluminum foil. Each thickness of the first electrode layer 10 and the second electrode layer 20 is usually 10 to 20 μm.

The insulating layer 30 is composed of a flame-retardant nonwoven fabric 31 and a flame-retardant tape 32 having adhesive on both sides. is adhered to the electrode layer 20 of the

In order to adjust the thickness of the insulating layer 30, a plurality of flame-retardant nonwoven fabrics 31 and a plurality of flame-retardant tapes 32 may be alternately laminated. The insulating layer 30 of this embodiment has two layers of flame-retardant nonwoven fabric 31 and three layers of flame-retardant tape 32 . The thickness of the insulating layer 30 is usually 300 μm or more, preferably 500 μm or more. Since each electrode layer will be spaced apart moderately by this, erroneous detection can be suppressed.

The flame-retardant nonwoven fabric 31 preferably has hydrophobicity or water repellency in order to ensure the insulating properties of the insulating layer 30 . The flame-retardant nonwoven fabric 31 is made of thermoplastic resin such as polyethylene resin, polyester resin, polypropylene resin, polystyrene resin, vinyl acetate resin, polyamide resin, and acrylic resin.

The flame-retardant tape 32 is made of thermosetting resin such as phenol resin, epoxy resin, urethane resin, melamine resin, and alkyd resin.

Furthermore, the laminated sheet 1 of this embodiment has a flame-retardant tape 32 covering the second electrode layer 20 in order to be attached to the installation location. The back surface of the laminated sheet 1 is covered with a release sheet 5 so that the adhesiveness of the flame-retardant tape 32 does not decrease.

The release sheet 5 is preferably made of polyethylene terephthalate resin (PET) or the like.

As described above, the embodiment is shown as an example, but the laminated sheet according to the present invention is not limited to the configuration of the above embodiment. Moreover, the laminated sheet according to the present invention is not limited by the above effects. Various modifications can be made to the laminated sheet according to the present invention without departing from the gist of the present invention.

For example, in the above embodiment, the circular first opening 41 and the rectangular second opening 42 with rounded corners were shown, but the opening 40 including these is illustrated in FIGS. 10 to 12. The shape may be such that For example, either the first opening 41 or the second opening 42 may be rectangular (FIGS. 10(a), 11(a)), the first opening 41 and the second opening 42 may be circular (FIG. 10(b)).

Moreover, in the above-described embodiment, all the first openings 41 have the same shape, but the shape of a part of the first openings 41 may be different. Such different opening shapes include an elliptical shape (FIG. 12(b)).

Further, instead of arranging the openings 40 in the repeating unit 50 of the above embodiment, the openings 40 may be arranged so as to surround the wire connecting portion 51 (FIGS. 11(b), (c), and FIG. 12 ( a)). Also, the number of first openings 41 may be reduced (FIG. 12(c)).

The present invention will be further illustrated by the following examples.

[Manufacturing example]
A flame-retardant non-woven fabric (thickness: 250 μm) was adhered to a carbon-coated copper foil (thickness: 17 μm) using a flame-retardant tape (thickness: 100 μm) coated on both sides with a PET release sheet (thickness: 38 μm). A flame-retardant nonwoven fabric (thickness: 250 µm) is attached to the flame-retardant nonwoven fabric (thickness: 250 µm) with a flame-retardant tape (thickness: 100 µm), and a flame-retardant tape (thickness: 100 µm) is attached to the bonded flame-retardant nonwoven fabric. to form a first electrode layer made of carbon-coated copper foil and an insulating layer made of flame-retardant nonwoven fabric and flame-retardant tape. One release sheet (thickness: 38 μm) of the flame-retardant tape arranged on the outermost side was left without being released, and was used as a first sheet member.
Next, a flame-retardant tape (100 μm thick) was attached to another carbon-coated copper foil (17 μm thick). A release sheet on one side of the flame-retardant tape was not peeled off and was left as a second sheet member.
A first sheet member was stamped to form a plurality of apertures arranged as shown in FIG. That is, a circular first opening (diameter 2.5 mm) and a rectangular second opening with rounded corners (vertical dimension 7 mm, horizontal dimension 8.5 mm) are placed in the first Formed into a sheet member. Also, the ratio of the vertical and horizontal dimensions of the repeating unit was set to 4:7. In addition, the wire connecting portion of the repeating unit formed a circular region with a diameter of 6.0 mm.
The release sheet of the first sheet member having a plurality of openings was peeled off and attached to the surface of the copper foil of the second sheet member to form a laminated sheet.
A sheet piece of 60 mm×122.5 mm was cut out from the laminated sheet, and electric wires were connected to the electric wire connecting portion of the first electrode layer and the exposed surface of the second electrode layer to obtain a liquid detection sensor.

[Evaluation of detection characteristics]
The detection characteristics of 50 liquid detection sensors manufactured in the above manufacturing example were evaluated. A liquid detection sensor was connected to a multi-circuit water leakage detector (manufactured by Tatsuta Densen Co., Ltd., AD-AS-5RDM), and 100 μS/cm saline solution was dropped as test water at a rate of 0.05 mL/s. If the resistance value between the electrodes became 25 kΩ or less before 5 mL of test water was dripped onto the liquid detection sensor, it was determined that the liquid detection sensor had good detection characteristics. Table 1 shows the results.

As shown in Table 1, the average drop amount of the test water was 1.21 mL when the resistance value between the electrodes was 25 kΩ or less, and the maximum was 2.25 mL. Therefore, it was confirmed that the liquid detection sensor has good detection characteristics.

[Evaluation of insulation resistance]
Using an insulation resistance meter, the insulation resistance of 50 liquid detection sensors was measured. As a result, the insulation resistance of all 50 liquid detection sensors was 4000 MΩ or more. Therefore, it was confirmed that the above-described liquid detection sensor is less prone to erroneous detection.

1: laminated sheet, 2: sheet piece, 3: electric wire, 5: release sheet, 6: connecting material, 6a: solder, 6b: terminal,
10: first electrode layer, 11: conductive portion, 12: opening,
20: second electrode layer, 21: exposed surface,
30: insulating layer, 31: flame-retardant nonwoven fabric, 32: flame-retardant tape,
40: opening, 41: first opening, 42: second opening,
50: repeating unit, 51: wire connection part, 510: circular area, 52: half unit,
60: sandwiching body, 61: first conducting portion, 62: second conducting portion,
100: liquid detection sensor

Claims (5)

a first electrode layer, a second electrode layer, and an insulating layer disposed between the first electrode layer and the second electrode layer, wherein the first electrode layer and the insulating layer A laminated sheet having a plurality of openings that penetrate through and expose the second electrode layer, and constitutes a detection unit for detecting liquid,
A laminated sheet comprising a plurality of repeating units each having a plurality of openings, wherein a plurality of the repeating units are arranged in the vertical direction and the horizontal direction. 2. The laminated sheet according to claim 1, wherein said repeating unit is rectangular and has a ratio of vertical dimension to horizontal dimension of 3:1 to 1:3. The first electrode layer of the repeating unit has a conductive portion made of a conductive material and an opening formed with the opening but not provided with the conductive material,
3. The laminate sheet according to claim 1, wherein said conductive portion includes a wire connecting portion wider than a circular area with a diameter of 4.0 mm. the plurality of openings of the repeating unit include connection openings for connecting electric wires to the exposed surface of the second electrode layer;
4. The laminate sheet according to claim 3, wherein the wire connecting portion and the connection opening are aligned in the vertical direction or the horizontal direction in the repeating unit. The detection unit made of a sheet piece cut from the laminated sheet according to any one of claims 1 to 4, and a pair of electric wires,
The liquid detection sensor, wherein the electric wire is electrically connected to each of the first electrode layer and the second electrode layer of the sheet piece.

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