Temperature difference sensor

Abstract

To provide a temperature difference sensor that can identify heat-generating locations using thermoelectric conversion elements.SOLUTION: A temperature difference sensor (1) includes a sheet body (2) containing an ion conductor containing a redox species capable of thermoelectric conversion, and a pair of electrodes (3), (4) in contact with the sheet body and arranged separately in the surface direction of the sheet body.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a temperature difference sensor. [Background technology]

[0002] Thermoelectric conversion materials have been attracting attention in recent years for their ability to convert minute amounts of energy, such as waste heat, into electricity. In particular, expectations are high for thin, highly efficient thermoelectric conversion materials as energy sources for mobile devices. However, while conventional alloy-based thermoelectric conversion materials have high thermal conductivity, they suffer from the problem of low Seebeck coefficients (Se).

[0003] Therefore, thermochemical batteries using solutions of oxidizable and reducible ions have been attracting attention (for example, Non-Patent Document 1). While the Seebeck coefficient (Se) of conventional solid thermoelectric alloys is approximately 0.2 mV / K, the Seebeck coefficient (Se) of the above-mentioned thermochemical batteries can be increased by one order of magnitude.

[0004] Furthermore, Patent Documents 1 and 2 disclose a thermoelectric sensor that uses a thermoelectric conversion element that includes a solution containing a redox pair (corresponding to an ionic conductor) and a pair of electrodes in contact with the solution to sense the temperature difference between the electrodes. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6511708 [Patent Document 2] Japanese Patent Publication No. 2023-54907 [Non-patent literature]

[0006] [Non-Patent Document 1] Theodore J. Abraham et al., "High Seebeck coefficient redox ionic liquid electrolytes for thermal energy harvesting," Energy & Environmental Science, (UK), 2013, Vol. 6, pp. 2639-2645 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the above-mentioned prior art does not specifically describe a thermoelectric sensor using a thermoelectric conversion element, and has not yet been put to practical use, and cannot be used to identify a heat generating location.

[0008] An object of one embodiment of the present invention is to provide a temperature difference sensor that can identify a heat-generating location by using a thermoelectric conversion element. [Means for solving the problem]

[0009] In order to solve the above problem, a temperature difference sensor according to one embodiment of the present invention comprises a sheet body containing an ion conductor including a redox species capable of thermoelectric conversion, and a pair of electrodes in contact with the sheet body and arranged separately in the surface direction of the sheet body. [Effects of the Invention]

[0010] According to one aspect of the present invention, a temperature difference sensor capable of identifying a heat-generating location by using a thermoelectric conversion element can be realized. [Brief explanation of the drawings]

[0011] [Figure 1]1 is a perspective view of a temperature difference sensor according to a first embodiment, as viewed from above. [Figure 2] 1 is a perspective view of a temperature difference sensor according to a first embodiment, as viewed from below. FIG. [Figure 3] 1 is a conceptual diagram showing a state in which the temperature difference sensor according to the first embodiment is used to monitor whether or not a measurement object is partially heated. [Figure 4] FIG. 10 is a perspective view of a temperature difference sensor according to a second embodiment, as viewed from above. [Figure 5] FIG. 10 is a perspective view of a temperature difference sensor according to a second embodiment, as viewed from below. [Figure 6] FIG. 10 is an image diagram showing a state in which the presence or absence of localized heat generation in a measurement object is monitored using the temperature difference sensor according to the second embodiment. [Figure 7] FIG. 11 is a perspective view of a temperature difference sensor according to a third embodiment, as viewed from above. [Figure 8] FIG. 11 is a perspective view of a temperature difference sensor according to a third embodiment, as viewed from below. [Figure 9] FIG. 10 is an image diagram showing a state in which the presence or absence of partial heat generation in a measurement object is monitored using a temperature difference sensor according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] [Embodiment 1] Hereinafter, one embodiment of the present invention will be described in detail.

[0013] (Configuration of temperature difference sensor 1) Fig. 1 is a perspective view of the temperature difference sensor 1 according to this embodiment as seen from above, and Fig. 2 is a perspective view of the temperature difference sensor 1 according to this embodiment as seen from below.

[0014] 1 and 2, the temperature difference sensor 1 includes a sheet member 2 containing an ion conductor that contains a redox species capable of thermoelectric conversion, and a pair of electrodes 3 and 4 that are in contact with the sheet member 2 and are arranged separately in the plane direction of the sheet member 2. The sheet member 2 containing the ion conductor and the pair of electrodes 3 and 4 form a thermoelectric conversion element.

[0015] Specifically, in this embodiment, the sheet 2 includes a first region (first section) 2A and a second region (second section) 2B aligned in the surface direction. The upper surface of the sheet 2 is the front surface, and the lower surface of the sheet 2 is the back surface.

[0016] In the sheet member 2, the ion conductor contained in the first region 2A and the ion conductor contained in the second region 2B have the same sign of the Seebeck coefficient.

[0017] In this embodiment, the area of ​​a single sheet 2 made of the same ion conductor is divided into two areas in the surface direction to form a first area 2A and a second area 2B. For example, the sheet 2 has a surface area of ​​10 cm 2 It is a gel sheet of 5cm 2 The area is divided into a first area 2A and a second area 2B.

[0018] In the sheet member 2, the first region 2A and the second region 2B may be insulated from each other. That is, there may or may not be a partition made of an insulating material between the first region 2A and the second region 2B. If there is a partition and the thermal conductivity of the partition is lower than that of the sheet member 2, the first region 2A and the second region 2B are less susceptible to the influence of each other's temperatures, resulting in better temperature resolution.

[0019] The sheet member 2 can be made of an ionic conductor containing redox species, for example, potassium ferrocyanide and potassium ferricyanide. However, the ionic conductor contained in the sheet member 2 is not limited to this, and any ionic conductor containing redox species capable of thermoelectric conversion may be used. The ionic conductor may be a redox species solution, a gel containing redox species, or the like. The ionic conductor containing redox species, potassium ferrocyanide and potassium ferricyanide, will be described in more detail in (1) of embodiment 4.

[0020] One electrode 3 of the pair of electrodes 3, 4 is arranged to pass through the front surface 2Aa of the first region 2A and the back surface 2Bb of the second region 2B. The other electrode 4 of the pair of electrodes 3, 4 is arranged to pass through the front surface 2Ba of the second region 2B and the back surface 2Ab of the first region 2A.

[0021] Insulating materials 5 and 6 are disposed on both ends of the sheet member 2 in a direction perpendicular to the direction in which the first region 2A and the second region 2B are arranged. The insulating materials 5 and 6 are not essential, and are not required as long as the sheet member 2 can be molded so as not to short-circuit the pair of electrodes 3 and 4.

[0022] One electrode 3 is connected from the front surface 2Aa of the first region 2A through the insulating material 6 to the back surface 2Bb of the second region 2B. More specifically, one electrode 3 extends from the end on the insulating material 5 side to the end on the insulating material 6 side on the front surface 2Aa of the first region 2A, passes through the inside or outside (the side opposite to the sheet body 2) of the insulating material 6 to the back surface 2Bb of the second region 2B. The one electrode 3 that has reached the back surface 2Bb of the second region 2B extends from the end on the insulating material 6 side to the end on the insulating material 5 side on the back surface 2Bb of the second region 2B, passes through the underside of the insulating material 5, and is drawn out to the outside.

[0023] The other electrode 4 is connected from the front surface 2Ba of the second region 2B through the insulating material 5 to the back surface 2Ab of the first region 2A. More specifically, the other electrode 4 extends from the end on the insulating material 6 side to the end on the insulating material 5 side on the front surface 2Ba of the second region 2B, passes through the inside or outside of the insulating material 5, and reaches the back surface of the first region 2A. The other electrode 4 that has reached the back surface of the first region 2A extends from the end on the insulating material 5 side to the end on the insulating material 6 side on the back surface 2Ab of the first region 2A, passes through the underside of the insulating material 6, and is drawn out to the outside.

[0024] 1 and 2 show an example of linear electrodes using gold or platinum wires as the pair of electrodes 3, 4. However, the pair of electrodes 3, 4 may be planar electrodes made of graphite or the like that contact the entire surfaces of the first region 2A and the second region 2B. In this case, the pair of electrodes 3, 4 must be insulated so that adjacent portions on the front surfaces 2Aa, 2Ba and back surfaces 2Ab, 2Bb of the first region 2A and the second region 2B do not come into contact with each other.

[0025] (Measurement using temperature difference sensor 1) 3 is an image diagram showing a state in which the temperature difference sensor 1 is used to monitor whether or not there is partial heat generation in a measurement object 100. Measurement object 100 has a first portion 101 and a second portion 102 that may generate heat. Note that in FIG. 3, measurement object 100 is placed on the upper surface (front surface side) of temperature difference sensor 1, but measurement object 100 can also be placed on the lower surface (rear surface side) of temperature difference sensor 1.

[0026] Temperature difference sensor 1 is designed to have a shape that matches measurement object 100 so that first region 2A and second region 2B of sheet member 2 are positioned at first portion 101 and second portion 102 of measurement object 100 placed thereon.

[0027] When measuring the measurement object 100, the sheet member 2 is brought into contact with the measurement object 100. The contact between the sheet member 2 and the measurement object 100 is not limited to direct contact, and a heat-transferable protective sheet or the like may be interposed between them.

[0028] When partial heat generation occurs in the measurement object 100, heat is applied to the front surface of the sheet member 2. Because the back surface is not in contact with the measurement object 100, the temperature of the front surface of the sheet member 2 in contact with the measurement object 100 and the temperature of the back surface of the sheet member 2 not in contact with the measurement object 100 are different.

[0029] A positive pole is attached to one electrode 3, and a negative pole to the other electrode 4. The sheet body 2 is a gel containing redox species of potassium ferrocyanide and potassium ferricyanide. In this case, when the surface side of the sheet body 2 is at a high temperature, a thermoelectric power of +1.4 mV / K is generated in the first region 2A, and a thermoelectric power of -1.4 mV / K is generated in the second region 2B.

[0030] The generated thermoelectromotive force can be evaluated by the sum of the voltages at the pair of electrodes 3 and 4 in the first and second regions 2A and 2B. When there is no temperature difference between the first and second regions 2A and 2B, the thermoelectromotive forces generated in the first and second regions 2A and 2B cancel each other out, resulting in the initial potential (OCV: open circuit voltage) between the electrodes of the ionic conductor. The initial potential of the ionic conductor can be easily evaluated by applying zero-point correction through calculations on the instrumentation side.

[0031] On the other hand, when the temperature of the first region 2A is higher than that of the second region 2B, the thermoelectromotive force tends to be positive. In other words, when the voltmeter connected to the pair of electrodes 3, 4 indicates a positive value, it can be determined that the first part 101 in contact with the first region 2A is a heat-generating part.

[0032] Similarly, when the temperature of the second region 2B is higher than that of the first region 2A, the thermoelectromotive force tends to be negative. In other words, when the voltmeter connected to the pair of electrodes 3, 4 indicates a negative value, it can be determined that the second part 102 in contact with the second region 2B is a heat generating part.

[0033] Here, the absolute value indicated by the voltmeter represents the degree of the temperature difference between the first region 2A and the second region 2B, and the larger the absolute value, the larger the temperature difference.

[0034] (effect) According to the above configuration, when localized heat generation or the like occurs in the measurement target 100, temperature unevenness occurs in the surface direction of the sheet member 2, to which the temperature of the measurement target 100 is transferred, and the temperature unevenness causes potential unevenness in the surface direction of the sheet member 2. Potential unevenness in the sheet member 2 can be detected by measuring the potential of each of the pair of electrodes 3 and 4 that contact the sheet member 2. By detecting the potential difference between the pair of electrodes 3 and 4, it is possible to identify high-temperature areas in the sheet member 2, and the part of the measurement target 100 that is in contact with the high-temperature area can be identified as the heat-generating location.

[0035] Furthermore, in conventional technology, two temperature sensors are required to detect and evaluate the temperature difference between two locations on the measurement object 100, and the difference between the detected values ​​of the two temperature sensors must be calculated on the calculation device side. In contrast, with the above configuration, a single temperature difference sensor can directly measure the temperature difference between two locations on the measurement object 100. This is expected to result in higher accuracy and improved response speed when monitoring and controlling the temperature difference of the measurement object in heating processes, cooling processes, etc.

[0036] Furthermore, with the above configuration, by connecting one electrode 3 to a positive terminal and the other electrode 4 to a negative terminal, it is possible to monitor the thermoelectromotive forces generated in the first region 2A and the second region 2B in reverse.

[0037] This makes it possible to identify whether the higher temperature area in the sheet body 2 is the first area 2A or the second area 2B, even if the first area 2A and the second area 2B are close to each other and the temperature difference is slight, and to identify the part of the measurement object 100 in contact with the higher temperature area as the heat generating point.

[0038] [Embodiment 2] Hereinafter, another embodiment of the present invention will be described in detail. For the sake of convenience, the same reference numerals will be used to designate components having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0039] (Configuration of temperature difference sensor 11) Fig. 4 is a perspective view of the temperature difference sensor 11 according to this embodiment as seen from above. Fig. 5 is a perspective view of the temperature difference sensor 11 according to this embodiment as seen from below.

[0040] 4 and 5, temperature difference sensor 11 includes sheet member 12 containing an ion conductor that contains a redox species capable of thermoelectric conversion, and a pair of electrodes 13 and 14 that are in contact with sheet member 12 and are arranged separately in the plane direction of sheet member 12. Sheet member 12 containing the ion conductor and the pair of electrodes 13 and 14 form a thermoelectric conversion element.

[0041] Specifically, in this embodiment, the sheet 12 includes a first region (first section) 2A and a second region (second section) 2B aligned in the surface direction. The upper surface of the sheet 12 is the front surface, and the lower surface of the sheet 12 is the back surface.

[0042] In the sheet member 12, the ion conductor contained in the first region 12A and the ion conductor contained in the second region 12B have Seebeck coefficients with different signs.

[0043] In this embodiment, an ion conductor is used in which the direction of the thermoelectric power generated is opposite between the first region 12A and the second region 12B. For example, the sheet member 12 has a surface area of ​​10 cm 2 It is a gel sheet of 5cm 2 The sheet 12 is divided into a first region 12A and a second region 12B, each of which is made up of a first region 12A and a second region 12B. The first region 12A uses an ion conductor that generates a thermoelectric power on the positive side when the surface side of the sheet 12 is at a high temperature, and the second region 12B uses another ion conductor that generates a thermoelectric power on the negative side when the surface side of the sheet 12 is at a high temperature. The other ion conductor will be described in more detail in (2) of embodiment 4.

[0044] In the sheet member 12, the first region 12A and the second region 12B are insulated from each other.

[0045] The combination of ionic conductors used in the sheet body 12, which have opposite directions of thermoelectric power, is, for example, an ionic conductor containing redox species of potassium ferrocyanide and potassium ferricyanide, and an ionic conductor containing iodide ions [I - ] and triiodide ion [I 3- ] is a combination of ionic conductors.

[0046] One electrode 13 of the pair of electrodes 13, 14 is arranged so as to pass through the surface 12Aa of the first region 12A and the surface 12Ba of the second region 12B, and the other electrode 14 of the pair of electrodes 13, 14 is arranged so as to pass through the back surface 12Ab of the first region 12A and the back surface 12Bb of the second region 12B.

[0047] Specifically, one electrode 13 extends from the end on the insulating material 5 side to the end on the insulating material 6 side on the surface 12Ba of the second region 12B, passes through the upper surface of the insulating material 6, and reaches the surface 12Aa of the first region 12A. The one electrode 13 that has reached the surface 12Aa of the first region 12A extends from the end on the insulating material 6 side to the end on the insulating material 5 side on the surface 12Aa of the first region 12A, passes through the upper surface of the insulating material 5, and is drawn out to the outside.

[0048] The other electrode 14 extends from the end on the insulating material 6 side to the end on the insulating material 5 side on the back surface 12Ab of the first region 12A, passes through the underside of the insulating material 5, and reaches the back surface 12Bb of the second region 12B. The other electrode 14 that has reached the back surface 12Bb of the second region 12B extends from the end on the insulating material 5 side to the end on the insulating material 6 side on the back surface 12Bb of the second region 12B, passes through the underside of the insulating material 6, and is drawn out to the outside.

[0049] 4 and 5 show linear electrodes using gold or platinum wires as the pair of electrodes 13, 14. However, the pair of electrodes 13, 14 may be planar electrodes made of graphite or the like that contact the entire surfaces of the first region 12A and the second region 12B. In this case, the front and back surfaces of the first region 12A and the second region 12B must be insulated from each other so that adjacent portions of the pair of electrodes 13, 14 do not come into contact with each other.

[0050] (Measurement using temperature difference sensor 11) 6 is an image diagram showing a state in which the presence or absence of partial heat generation in measurement object 100 is monitored using temperature difference sensor 11. Measurement object 100 has first portion 101 and second portion 102 that may generate heat. In FIG. 6, measurement object 100 is placed on the upper surface (front surface side) of temperature difference sensor 11, but measurement object 100 can also be placed on the lower surface (rear surface side) of temperature difference sensor 11.

[0051] Temperature difference sensor 11 is designed to have a shape that matches measurement object 100 so that first region 2A and second region 2B of sheet member 2 are positioned at first portion 101 and second portion 102 of measurement object 100 placed thereon.

[0052] When measuring the measurement object 100, the sheet member 12 is brought into contact with the measurement object 100. The contact between the sheet member 12 and the measurement object 100 is not limited to direct contact, and a heat-transferable protective sheet or the like may be interposed between them.

[0053] When partial heat generation occurs in the measurement object 100, heat is applied to the front surface of the sheet body 12. Because the back surface is not in contact with the measurement object 100, the temperature of the front surface of the sheet body 12 that is in contact with the measurement object 100 and the temperature of the back surface of the sheet body 12 that is not in contact with the measurement object 100 are different.

[0054] Depending on the ion conductor contained in the first region 12A and the second region 12B of the sheet member 12, one electrode 13 is attached with either a positive pole or a negative pole, and the other electrode 14 is attached with the other pole.

[0055] A positive electrode is attached to one electrode 13, and a negative electrode is attached to the other electrode 14. The first region 12A of the sheet body 12 is a gel containing redox species of potassium ferrocyanide and potassium ferricyanide, and the first region 12A contains iodide ions [I - ] and triiodide ion [I 3-In this case, when the temperature on the front surface side of the sheet member 12 is high, a thermoelectromotive force of −1.4 mV / K is generated in the first region 2A and a thermoelectromotive force of 0.8 mV / K is generated in the second region 2B.

[0056] Since the first region 12A and the second region 12B are connected by a pair of electrodes 13 and 14, the generated thermoelectromotive force becomes a combined voltage from each of them.

[0057] In other words, if the voltage when there is no temperature difference between the first region 2A and the second region 2B is taken as the reference voltage XmV / K, and if the terminals of a voltmeter are connected to a pair of electrodes 13, 14 and the value is close to XmV / K, it can be determined that no partial heat generation is occurring in the object to be measured 100.

[0058] On the other hand, when the temperature of first region 12A is higher than that of second region 12B, the thermoelectromotive force leans to the positive side of XmV / K. In other words, when the voltmeter connected to the pair of electrodes 13, 14 indicates a value greater than XmV / K, it can be determined that first portion 101 in contact with first region 12A is a heat-generating location.

[0059] Similarly, when the temperature of second region 12B is higher than that of first region 12A, the thermoelectromotive force leans toward the negative side of XmV / K. In other words, when the voltmeter connected to the pair of electrodes 13, 14 indicates a value smaller than XmV / K, it can be determined that second portion 102 in contact with second region 12B is a heat-generating location.

[0060] Here too, the absolute value indicated by the voltmeter represents the degree of the temperature difference between the first region 12A and the second region 12B, and the larger the absolute value, the larger the temperature difference.

[0061] (effect) According to the above configuration, by connecting one electrode 13 to a positive terminal and the other electrode 14 to a negative terminal, the thermoelectromotive forces generated in the first region 12A and the second region 12B can be monitored in reverse.

[0062] This makes it possible to identify whether the higher temperature area in the sheet body 12 is the first area 12A or the second area 12B, even if the first area 12A and the second area 12B are close to each other and the temperature difference is slight, and to identify the part of the measurement object 100 in contact with the higher temperature area as the heat generating point.

[0063] [Embodiment 3] Hereinafter, another embodiment of the present invention will be described in detail. For the sake of convenience, the same reference numerals will be used to designate components having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0064] (Configuration of temperature difference sensor 21) Fig. 7 is a perspective view of the temperature difference sensor 21 according to this embodiment as seen from above. Fig. 8 is a perspective view of the temperature difference sensor 21 according to this embodiment as seen from below.

[0065] 7 and 8, temperature difference sensor 21 includes sheet member 22 including an ion conductor containing a redox species capable of thermoelectric conversion, and a pair of electrodes 23 and 24 in contact with sheet member 22 and arranged separately in the plane direction of sheet member 22. Sheet member 22 including the ion conductor and the pair of electrodes 23 and 24 form a thermoelectric conversion element.

[0066] Specifically, in this embodiment, the sheet body 22 is configured in an elongated shape that is long in one direction. The upper surface of the sheet body 22 is the front surface, and the lower surface of the sheet body 22 is the back surface. The ion conductor contained in the sheet body 22 is the same in the longitudinal direction of the sheet body 22.

[0067] One electrode 23 of the pair of electrodes 23, 24 is arranged on the front or back surface of one end of the sheet body 22 in the longitudinal direction, and the other electrode of the pair of electrodes 23, 24 is arranged on the front or back surface of the other end of the sheet body 22 in the longitudinal direction.

[0068] In this embodiment, one electrode 23 is disposed on a surface 22a of the sheet 22 at one end 22A in the longitudinal direction, in the short direction across the sheet 22. The other electrode 24 is disposed on a surface 22a of the sheet 22 at the other end 22B in the longitudinal direction, in the short direction across the sheet 22. One of the ends of the pair of electrodes 23, 24 is drawn out to the outside of the sheet 22.

[0069] In Figures 7 and 8, the other electrode 24 is arranged on the surface 22a of the sheet body 22 on the other end 22B side in the longitudinal direction, but it may also be arranged in the short direction across the sheet body 22 on the back surface 22b of the sheet body 22 on the other end 22B side in the longitudinal direction, as shown by the virtual lines in Figures 7 and 8.

[0070] 7 and 8, the pair of electrodes 23 and 24 are illustrated as linear electrodes using gold or platinum wires, but the pair of electrodes 23 and 24 may also be wide, strip-shaped electrodes made of graphite or other material.

[0071] (Measurement using temperature difference sensor 21) 9 is an image diagram showing a state in which the presence or absence of local heat generation in measurement object 200 is monitored using temperature difference sensor 21. Measurement object 200 has first portion 201 and second portion 202 that may generate heat. The distance between first portion 201 and second portion 202 in measurement object 200 is greater than the distance between first portion 101 and second portion 2102 in measurement object 100.

[0072] In FIG. 9, the measurement object 200 is placed on the lower surface side (rear surface side) of the temperature difference sensor 21, but the measurement object 200 can also be placed on the upper surface side (front surface side) of the temperature difference sensor 21.

[0073] Temperature difference sensor 21 is placed on measurement object 200 with its longitudinal direction facing the line direction of first portion 201 and second portion 202. When localized heat generation occurs in measurement object 200, heat is applied from the back surface to the front surface of sheet member 22. Heat is applied uniformly in the thickness direction of sheet member 22, and the back surface of sheet member 22 that is in contact with measurement object 200 and the front surface of sheet member 22 that is not in contact with measurement object 200 have the same temperature.

[0074] Depending on the ion conductor contained in the sheet member 22, one of the electrodes 23 is attached as either a positive pole or a negative pole, and the other electrode 24 is attached as the other pole.

[0075] The sheet 22 is a gel containing redox species of potassium ferrocyanide and potassium ferricyanide. In this case, when the temperature of the end 22A of the sheet 22 is high, a thermoelectromotive force of −1.4 mV / K is generated between the end 22A and the other end 22B.

[0076] Therefore, when the terminals of a voltmeter are connected to the pair of electrodes 23, 24 and the voltmeter indicates a negative value, it can be determined that first portion 201 in contact with end portion 22A is a heat generating portion.

[0077] On the other hand, when the temperature of the other end 22B is higher than that of the end 22A, the thermoelectromotive force tends to be positive. In other words, when the voltmeter connected to the pair of electrodes 23, 24 indicates a positive value, it can be determined that the second portion 202 in contact with the other end 22B is a heat-generating portion.

[0078] Here, the absolute value indicated by the voltmeter represents the degree of the temperature difference between end 22A and end 22B (in the longitudinal direction of sheet 22), and the larger the absolute value, the larger the temperature difference.

[0079] (effect) According to the above configuration, by attaching either a positive or negative pole to one electrode 23 and the other pole to the other electrode 24, it is possible to monitor the thermoelectric power generated by the temperature difference in the longitudinal direction of the sheet body 22.

[0080] This limits the distance between the pair of electrodes 23, 24 to a temperature difference, but with a simple electrode arrangement, it is possible to identify whether the high temperature area on the sheet body 22 is on the one end 22A side or the other end 22B side in the longitudinal direction, and identify the part of the measurement object in contact with the side with the higher temperature as the heat-generating point.

[0081] [Embodiment 4] In embodiment 4, a configuration applicable to the above-described embodiments 1 to 3 will be described. For ease of explanation, members having the same functions as those described in the above embodiments will be denoted by the same reference numerals, and their description will not be repeated.

[0082] The pair of electrodes 3 and 4, the pair of electrodes 13 and 14, and the pair of electrodes 23 and 24 may be made of a metal or non-metal having a potential window that allows measurement of the reaction of the ion conductor used in the sheet body 2, the sheet body 12, and the sheet body 22. This allows the thermoelectromotive force caused by the temperature difference generated in the sheet body 2, the sheet body 12, and the sheet body 22 to be appropriately monitored.

[0083] Furthermore, in the sheets 2, 12, and 22, the ion conductor may be covered with an insulating vacuum sealing material. This configuration increases durability and makes the sheet resistant to deterioration over time. The vacuum sealing material may be an adhesive film based on an insulating material such as polyimide, PET, PE, or PP. However, the material must be selected so as not to impede heat conduction.

[0084] In this case, the sheet body 2, the sheet body 12, and the sheet body 22 may be covered with the vacuum sealing material by themselves, or the pair of electrodes 3, 4, the pair of electrodes 13, 14, and the pair of electrodes 23, 24 may be covered with the vacuum sealing material together with the pair of electrodes in their arranged state.

[0085] The following describes an example of the ion conductor contained in the sheets 2, 12, and 22. Hereinafter, the sheet containing the ion conductor will be referred to as an ion conductive film, and the ion conductor will be referred to as a liquid.

[0086] <1-1. Ion-conducting membrane or liquid> The ion-conductive membrane may be a membrane containing a redox species and a polymer. The redox species may be mixed in the polymer or supported by the polymer. The ion-conductive membrane may further contain a solvent. That is, the ion-conductive membrane may be a membrane in which a composition containing a redox species, a polymer, and optionally a solvent has lost its fluidity, or a membrane in which the composition is cured. The ion-conductive membrane may be a membrane in which a liquid containing a redox species and optionally a solvent is held within the three-dimensional structure of the polymer. The ion-conductive membrane may be a gel membrane containing a relatively large amount of solvent, or a non-gel membrane containing a small amount of solvent or no solvent.

[0087] Examples of such polymers include polyvinyl alcohol (PVA), polyvinylidene fluoride (PVDF), carboxymethyl cellulose (CMC), N,N-dimethylacrylamide / glycidyl methacrylate copolymer, epoxy resin, styrene butadiene rubber (SBR), and polyurethane. Substituents such as sulfonic acid groups, carboxyl groups, and phosphate groups may or may not be introduced into the polymer skeleton to impart ionic conductivity. In other words, the polymer that constitutes the ion-conductive membrane itself may or may not have ionic conductivity.

[0088] The liquid may be a solution containing a redox species and a solvent, i.e., a solution in which the redox species is dissolved in a solvent, or, when the redox species is an ionic liquid (room-temperature molten salt), the liquid containing the redox species may be a liquid without a solvent.

[0089] <1-2. Redox species> In this specification, the thermoelectrically convertible redox species refers to a compound that forms a redox pair, which undergoes an oxidation-reduction reaction due to a temperature difference, or a compound that generates a redox pair ion and its counter ion. Examples of redox pair compounds include quinone and hydroquinone. The redox pair ion and its counter ion may be a redox pair anion and its counter ion, or a redox pair cation and its counter ion, or a redox pair cation and its counter anion.

[0090] An example of a redox pair is the ferricyanide ion and the ferrocyanide ion [Fe(CN)6 3- ] / [Fe(CN)6 4- ], iodide ion and triiodide ion [I - ] / [I 3- ] etc.

[0091] Examples of cations that serve as counter ions include inorganic cations and organic cations. Only one type of cation may be used, or two or more types may be used in combination. In addition, only inorganic cations or organic cations may be used, or inorganic cations and organic cations may be used in combination.

[0092] Examples of inorganic cations serving as counter ions include alkali metal ions, alkaline earth metal ions, etc. Examples of alkali metal ions include lithium ions, sodium ions, and potassium ions, with potassium ions being preferred.

[0093] Examples of organic cations that serve as counter ions include imidazolium cations, ammonium cations, pyridinium cations, and pyrrolidinium cations.

[0094] Examples of imidazolium cations include 1-methylimidazolium cation, 1-ethylimidazolium cation, 1-propylimidazolium cation, 1-butylimidazolium cation, 1,3-dimethyl-imidazolium cation, 1-ethyl-3-methylimidazolium cation, 1-propyl-3-methylimidazolium cation, 1-butyl-3-methylimidazolium cation, 1-methyl-3-octylimidazolium cation, and 1-hexyl-3-methylimidazolium cation.

[0095] Examples of the ammonium cation include diethylmethyl-(2-methoxyethyl)ammonium cation, choline cation, tetramethylammonium cation, and triethylmethylammonium cation.

[0096] Examples of the pyridinium cation include 1-butyl-4-methylpyridinium cation.

[0097] Examples of pyrrolidinium cations include N-(2-methoxyethyl)-N-methylpyrrolidinium cations.

[0098] Cations that form redox pairs include alkali metal cations (e.g., Li and Li + , K and K + ), Fe 2+ and Fe 3+Examples of counter ion anions include bis(fluorosulfonyl)imide (FSI) anion, bis(trifluoromethanesulfonyl)imide (TFSI) anion, hexafluorophosphate (PF6) anion, tetrafluoroborate (BF4) anion, chloride ion, and the like. For example, an alkali metal salt can also be used as the redox species. When the redox species is an alkali metal salt, it is preferable to use it in combination with a glycol ether solvent or crown ether, which will be described later, as this increases the entropy change.

[0099] <1-3. Solvent> The ion-conductive membrane or liquid may contain a solvent. Examples of the solvent include non-aqueous solvents and aqueous solvents. Examples of non-aqueous solvents include ethanol (a 2:1 molar mixture of ethylene glycol (EG) and choline chloride (ChCl)), dimethyl sulfoxide (DMSO), 1-ethyl-3-methylimidazolium dicyanamide, glycerin, glycol ether solvents, and aromatic solvents. Examples of aqueous solvents include water and aqueous solutions of alcohols (e.g., ethylene glycol).

[0100] From the viewpoint of thermal stability, the solvents preferably have a boiling point of 150°C or higher at normal pressure. In this specification, normal pressure means 1 atmosphere. Examples of solvents having a boiling point of 150°C or higher at normal pressure include glycerin, ethylene glycol, and tetraglyme. Among these, tetraglyme, which has a boiling point of 150°C or higher at normal pressure and a small dielectric dissipation factor, is particularly preferred.

[0101] <1-4. Other ingredients> The ion-conductive membrane or liquid may contain components other than the redox species and solvent. For example, the ion-conductive membrane or liquid may further contain ions other than the anions and cations described as the redox species. From the viewpoint of improving ionic conductivity and reducing resistance, the ion-conductive membrane or liquid may contain a quaternary ammonium salt (Br salt, Cl salt, etc.) or may contain ions derived from the quaternary ammonium salt. Examples of quaternary ammonium salts include guanidinium chloride and dodecyltrimethylammonium bromide (DTAB).

[0102] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0103] 1, 11, 21 Temperature difference sensor 2, 12, 22 sheet body 2A, 12A 1st area 2B, 12B 2nd area 3, 13, 23 One electrode 4, 14, 24 Other electrode 22A One end 22B Other end

Claims

1. a sheet body including an ion conductor containing a redox species capable of thermoelectric conversion; A temperature difference sensor comprising: a pair of electrodes in contact with the sheet body and arranged apart in a surface direction of the sheet body.

2. the sheet body includes a first region and a second region aligned in the surface direction, the ion conductor included in the first region and the ion conductor included in the second region have the same sign of the Seebeck coefficient; one of the pair of electrodes is disposed so as to pass through the front surface of the first region and the back surface of the second region; 2. The temperature difference sensor according to claim 1, wherein the other electrode of the pair of electrodes is disposed so as to pass through the front surface of the second region and the back surface of the first region.

3. 3. The temperature difference sensor according to claim 2, wherein the first region and the second region of the sheet are insulated from each other.

4. the sheet body includes a first region and a second region aligned in a surface direction, the ion conductor included in the first region and the ion conductor included in the second region have Seebeck coefficients with different signs, one of the pair of electrodes is disposed so as to pass through a surface of the first region and a surface of the second region; 2. The temperature difference sensor according to claim 1, wherein the other electrode of the pair of electrodes is disposed so as to pass through the rear surface of the first region and the rear surface of the second region.

5. The sheet body has an elongated shape that is long in one direction, one of the pair of electrodes is disposed on the front or back surface of one end of the sheet body in the longitudinal direction, 2. The temperature difference sensor according to claim 1, wherein the other electrode of the pair of electrodes is disposed on the front or back surface of the other end of the sheet in the longitudinal direction.

6. 2. The temperature difference sensor according to claim 1, wherein the pair of electrodes are made of a metal or nonmetal having a potential window that allows measurement of the reaction of the ion conductor.

7. 2. The temperature difference sensor according to claim 1, wherein the ion conductor in the sheet member is covered with an insulating vacuum sealing material.

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