Temperature control module

Abstract

Provided is a temperature control module having high cooling ability and a thin profile, the temperature control module comprising a Peltier element and a vapor chamber layered on the Peltier element, the total thickness of the Peltier element and the vapor chamber being 1 mm or less.

Description

Temperature Control Module

[0001] The present invention relates to a temperature control module.

[0002] To control the temperature of specific components in various electronic devices, it has been proposed to use a Peltier element, a vapor chamber, or a temperature control module that combines these. For example, by placing a Peltier element or a vapor chamber near a component that is a heat source, it is expected that the cooling of the heat source will be promoted. In addition, by placing a Peltier element near a specific component, it is also possible to heat the component if necessary.

[0003] Patent Literature 1 describes a cold plate having a thermo-module including a thermoelement that absorbs heat on its upper surface and generates heat on its lower surface due to the Peltier effect, a flat heat pipe attached to the cooling portion of the thermo-module, and a heat pipe radiator provided on the heat-generating portion of the thermo-module. Patent Literature 2 describes a battery pack temperature control and power supply system including multiple battery cells, a plate-shaped vapor chamber interposed between a pair of battery cells, and a thermoelectric element arranged in close contact with the end surface of the vapor chamber. Patent Literature 3 describes a cooling system including multiple Peltier modules arranged perpendicular to the surface direction, a heat absorption flow path or a heat release flow path between a pair of Peltier modules, and the heat absorption surfaces and heat release surfaces of adjacent Peltier modules facing each other. It also describes that the heat absorption flow path and the heat release flow path are formed by a vapor chamber.

[0004] As the range of applications for temperature control modules expands, there is a demand for even thinner temperature control modules with higher cooling performance so that they can be installed in devices with limited installation space, such as thin and small portable electronic devices such as smartphones and laptops.

[0005] Japanese Patent Laid-Open No. 2-176377 Japanese Patent Laid-Open No. 2017-126418 Japanese Patent Laid-Open No. 2020-200980

[0006] However, the cold plate described in Patent Document 1 has thick heat pipes, making it impossible to make the entire cold plate thin. Furthermore, in the battery pack temperature control and power supply system described in Patent Document 2, the thermoelectric elements are installed perpendicular to the surface direction of the battery cells, which are the objects to be cooled, making it difficult to make the entire device thin. Furthermore, in the cooling system described in Patent Document 3, each Peltier module is 2 to 3 mm thick, and multiple Peltier modules and multiple heat absorption or heat release channels are repeatedly stacked, making it difficult to make the entire system thin.

[0007] In view of the above problems, an object of the present invention is to provide a thin temperature control module with high cooling performance.

[0008] The present inventors conducted extensive research to solve the above-mentioned problems, and discovered that the above-mentioned problems can be solved by setting the total thickness of the Peltier element and vapor chamber used in the temperature control module within a predetermined range, thereby completing the present invention. Specifically, the present invention provides the following [1] to [6]. [1] A temperature control module comprising a Peltier element and a vapor chamber stacked on the Peltier element, wherein the total thickness of the Peltier element and the vapor chamber is 1 mm or less. [2] A temperature control module comprising a Peltier element and a vapor chamber stacked on the Peltier element, wherein the thickness of the temperature control module is 1 mm or less. [3] The temperature control module according to [1] or [2], wherein the Peltier element comprises a thermoelectric conversion layer including multiple thermoelectric conversion elements, and the multiple thermoelectric conversion elements are a sintered body of a coating film of a composition containing a thermoelectric semiconductor material. [4] The temperature control module according to [3], wherein the composition containing a thermoelectric semiconductor material includes thermoelectric semiconductor particles, a polymer component, and an ionic compound. [5] The temperature control module according to any one of [1] to [4] above, wherein the Peltier element has a thermoelectric conversion layer including a plurality of thermoelectric conversion elements, and the plurality of thermoelectric conversion elements include a bismuth-tellurium compound. [6] The temperature control module according to any one of [1] to [5] above, which is a cooling module.

[0009] The present invention can provide a thin temperature control module with high cooling performance.

[0010] Fig. 6 is a cross-sectional view showing an example of a temperature control module; Fig. 7 is a cross-sectional view showing another example of a temperature control module; Fig. 8 is a cross-sectional view showing another example of a temperature control module; Fig. 9 is a cross-sectional view showing another example of a temperature control module; Fig. 10 is a bottom view of the temperature control module of Fig. 5; Fig. 11 is a plan view showing an example of a first sheet of a vapor chamber;

[0011] Hereinafter, an embodiment of the present invention will be described.

[0012] [Temperature Control Module] The temperature control module according to a first embodiment of the present invention comprises a Peltier element and a vapor chamber stacked on the Peltier element, with the total thickness of the Peltier element and the vapor chamber being 1 mm or less. By comprising a Peltier element and a vapor chamber, the temperature control module has high cooling performance. Furthermore, since the total thickness of the Peltier element and the vapor chamber is 1 mm or less, a thin temperature control module can be achieved. In addition, the above configuration makes the temperature control module lightweight and makes it easier to provide flexibility to the temperature control module.

[0013] In order to make the total thickness of the Peltier element and vapor chamber 1 mm or less, a thin Peltier element and a thin vapor chamber, each of which has a thickness of less than 1 mm, are used. The thin Peltier element can be obtained, for example, by using a Peltier element having a thermoelectric conversion layer formed by a coating method as described below. Furthermore, the thin vapor chamber can be realized, for example, by using a vapor chamber having a configuration in which two sheets having a plurality of ridges formed thereon are stacked together to enclose a working fluid, as shown in the embodiment described below, and in which a plurality of condensed liquid flow paths through which condensed liquid of the working fluid flows and a vapor flow path through which vaporized working fluid flows are formed.

[0014] A temperature control module according to a second embodiment of the present invention includes a Peltier element and a vapor chamber stacked on the Peltier element, and the temperature control module has a thickness of 1 mm or less. The temperature control module according to the second embodiment may include other layers, such as an intervening layer, in addition to the Peltier element and vapor chamber. By making the overall thickness of the temperature control module, including these other layers, 1 mm or less, it becomes possible to install the temperature control module in devices with limited installation space, or to reduce the overall thickness and size of the device. This also facilitates weight reduction and flexibility of the temperature control module. Examples of the intervening layer include an adhesive layer, an insulator layer, and a sealant layer. A specific layer in the Peltier element may also serve as the intervening layer. In this case, the total thickness of the Peltier element, including the specific layer that also serves as the intervening layer, and the vapor chamber may be 1 mm or less, and the overall thickness of the temperature control module may be 1 mm or less. Furthermore, in the temperature control module according to the second embodiment, the total thickness of the Peltier element and the vapor chamber may be 1 mm or less. Hereinafter, the first and second embodiments may be collectively referred to as "the present embodiment."

[0015] The temperature control module according to this embodiment may be a cooling module that performs cooling exclusively, or may be a module that can switch between cooling and heating.

[0016] <Peltier Element> A Peltier element is an electronic component including a thermoelectric semiconductor that exhibits the Peltier effect. A Peltier element preferably has a thermoelectric conversion layer including a plurality of P-type thermoelectric semiconductor elements and a plurality of N-type thermoelectric semiconductor elements arranged alternately. The top surfaces of adjacent P-type and N-type thermoelectric semiconductor elements in a first set are electrically connected, and the bottom surfaces of the N-type thermoelectric semiconductor elements of the first set are electrically connected to the bottom surfaces of the P-type thermoelectric semiconductor elements of a second set. The top surfaces of the P-type thermoelectric semiconductor elements of the second set are electrically connected to the top surfaces of the N-type thermoelectric semiconductor elements that are paired with the P-type thermoelectric semiconductor elements of the second set and that together constitute the second set. The bottom surfaces of the N-type thermoelectric semiconductor elements of the second set are electrically connected to the bottom surfaces of the P-type thermoelectric semiconductor elements of a third set. Similar configurations are repeated. Then, by passing current through the first thermoelectric semiconductor element and the last thermoelectric semiconductor element, a heat absorption phenomenon occurs at the electrical junction where the current flows in the order N → P, and a heat dissipation phenomenon occurs at the electrical junction where the current flows in the order P → N. For this reason, one surface of the Peltier element absorbs heat and the other surface generates heat, and by bringing the heat absorption surface of the Peltier element close to or in contact with an object to be cooled, the object can be cooled.

[0017] From the viewpoint of achieving a thinner design, the temperature control module preferably includes a thermoelectric conversion layer including a plurality of thermoelectric conversion elements as described above, and further preferably uses a Peltier element in which the plurality of thermoelectric conversion elements are formed by sintering a coating film of a composition containing a thermoelectric semiconductor material. Using a Peltier element in which the thermoelectric conversion elements are formed by sintering a coating film of a composition containing a thermoelectric semiconductor material makes it easier to achieve a thickness of less than 1 mm. The thickness of the Peltier element is preferably 50 μm or more, more preferably 75 μm or more, and even more preferably 150 μm or more. Furthermore, the thickness of the Peltier element is preferably 650 μm or less, more preferably 550 μm or less, and even more preferably 450 μm or less. In other words, the thickness of the Peltier element is preferably 50 μm or more and less than 1 mm. The composition containing the thermoelectric semiconductor material may contain a polymer component, an ionic compound, and thermoelectric semiconductor particles. A coating film formed using such a composition is suitable for forming a thermoelectric conversion layer having excellent thermoelectric conversion properties by coating. The thermoelectric conversion layer formed from the coating film may be provided on a substrate, but it can also be peeled off from the support after being formed on the support, and the presence of a substrate is not essential. This makes it easy to thin the thermoelectric conversion layer, making it suitable for application to portable electronic devices and the like, which are in high demand for thinness. The coating film may be formed, for example, by gravure printing or by inkjet printing. Adjacent thermoelectric semiconductor elements may be spaced apart, and the gaps between the adjacent thermoelectric semiconductor elements may be filled with a reinforcing material. Various insulators, etc., as described below, can be used as the reinforcing material. Materials for forming the thermoelectric conversion layer and their formation by coating will be described later.

[0018] Other layers may be provided in the Peltier element as needed. For example, a coating layer consisting of a single layer or multiple layers may be disposed to cover the thermoelectric conversion layer on at least one of the main surfaces to protect the thermoelectric conversion layer. The coating layer may also include a sealing layer. If the coating layer is a single layer, the coating layer itself may also serve as a sealing layer. If the coating layer is composed of multiple layers, any of the layers may include a sealing layer. If the coating layer includes a sealing layer, permeation of water vapor in the atmosphere can be more effectively suppressed, making it easier to maintain the performance of the Peltier element for a long period of time.

[0019] <Vapor Chamber> A vapor chamber is a heat diffusion device comprising a pair of opposing flat plates and a working fluid sealed between the plates. The working fluid transports heat by circulating while undergoing phase changes, transporting and diffusing heat from a heat source to cool the heat source. Conventional vapor chambers can be used as the vapor chamber constituting the temperature control module. For example, as shown in the following embodiment, a vapor chamber can be used, which has a configuration in which two uneven sheets are stacked together to seal the working fluid, and which has multiple condensate flow paths through which condensed liquid of the working fluid flows and a vapor flow path through which vaporized working fluid flows. Alternatively, a vapor chamber can be used, in which a mesh wick is disposed between a pair of flat plates and the working fluid is sealed, and the condensed working fluid is circulated through the mesh wick.

[0020] While there are no particular limitations on the material of the pair of flat plates or pair of sheets that make up the vapor chamber, metals with high thermal conductivity are preferred, such as copper and copper alloys. The type of working fluid sealed in the sealed space of the vapor chamber is also not particularly limited, but examples include pure water, ethanol (boiling point: 78.3°C), methanol (boiling point: 64.7°C), acetone (boiling point: 56°C), and naphthalene (boiling point: 218°C). The operating temperature range of the vapor chamber is relatively low when using ethanol or acetone as the working fluid (for example, approximately -10 to +130°C for ethanol), and relatively high when using naphthalene as the working fluid (approximately 250 to 400°C). When using pure water as the working fluid, the operating temperature range is intermediate, approximately 30 to 200°C.

[0021] There is no particular restriction on the order in which the vapor chamber and Peltier element are stacked; the Peltier element may be stacked on top of the vapor chamber, or the vapor chamber may be stacked on top of the Peltier element. The two may also be stacked with another layer in between. There is no particular restriction on the areas of the vapor chamber and the Peltier element; however, for example, when cooling a specific part that serves as a heat source, it is preferable that the Peltier element have an area corresponding to that part, and the vapor chamber have a larger area. Furthermore, when promoting heat dissipation from the vapor chamber using a Peltier element, it is preferable that the Peltier element have an area equal to or larger than that of the vapor chamber, or that multiple Peltier elements with an area smaller than the vapor chamber be arranged so as to correspond to the area of ​​the vapor chamber.

[0022] Hereinafter, configuration examples of temperature control modules according to embodiments of the present invention will be described with reference to the drawings. All drawings are schematic and may be exaggerated to facilitate understanding. Furthermore, the same reference numerals may be omitted from the description of similar components and structures.

[0023] <Temperature Control Module Configuration Example 1> FIG. 1 is a cross-sectional schematic diagram showing an example of a temperature control module according to the present embodiment. The temperature control module 1A shown in FIG. 1 has a configuration in which a Peltier element 40 is stacked on one main surface (the bottom surface in FIG. 1 ) of a vapor chamber 30. The temperature control module 1A is flat. The shape of the temperature control module 1A when viewed from above is not particularly limited, and it can be rectangular, square, polygonal, circular, elliptical, or other shapes. When using the temperature control module 1A, a temperature-controlled member 50 (hereinafter referred to as the temperature-controlled member 50) is placed in contact with the main surface of the Peltier element 40 opposite the vapor chamber 30 (the bottom surface in FIG. 1 ), as shown by the dashed line in FIG. 1 . In the temperature control module 1A, the total thickness D1 of the thickness D3 of the Peltier element 40 and the thickness D2 of the vapor chamber 30 is 1 mm or less. In the temperature control module 1A, the thickness D1 is also the thickness D of the temperature control module 1A. By making the thickness D1 1 mm or less, the temperature control module 1A can be made thin, allowing it to be placed in a narrow space. It is also easy to achieve light weight and flexibility.

[0024] The area of ​​the Peltier element 40 in a plan view is smaller than the area of ​​the vapor chamber 30. The Peltier element 40 is disposed so as to contact the underside near the center of the vapor chamber 30. Because the area of ​​the vapor chamber 30 is larger than the area of ​​the Peltier element 40, the heat emitted from the Peltier element 40 can be efficiently diffused in the planar direction.

[0025] The Peltier element 40 includes a thermoelectric conversion layer 48 including a plurality of P-type thermoelectric conversion elements 43 and a plurality of N-type thermoelectric conversion elements 44 arranged alternately. The P-type thermoelectric conversion elements 43 and the N-type thermoelectric conversion elements 44 are alternately electrically connected by first connection electrodes 41 and second connection electrodes 42. An insulator layer 46 is provided around the P-type thermoelectric conversion elements 43 and the N-type thermoelectric conversion elements 44. A filler layer 45 is provided around and on the top surface of the first connection electrode 41 located on the upper surface of the Peltier element 40. A coating layer 47 is provided on the lower surface of the Peltier element 40 to cover the second connection electrodes 42, the P-type thermoelectric conversion elements 43, and the N-type thermoelectric conversion elements 44.

[0026] The vapor chamber 30 includes a first sheet 10 and a second sheet 20, each having a plurality of ridges formed at positions corresponding to each other. The first sheet 10 and the second sheet 20 are joined together so that the plurality of ridges 13 of the first sheet 10 and the plurality of ridges 23 of the second sheet 20 overlap each other, and a working fluid is sealed in a sealed space 31 formed between the first sheet 10 and the second sheet 20. The detailed configuration of the vapor chamber 30 will be described later.

[0027] In the temperature control module 1A, for example, when the temperature-control target component 50 is brought into contact with the underside of the Peltier element 40 of the temperature control module 1A to cool the temperature-control target component 50, current is passed through the Peltier element 40, creating a temperature difference between the underside and the upper side, which acts as the heat absorption and heat dissipation sides, respectively. Heat absorbed from the temperature-control target component 50 is then dissipated from the upper side of the Peltier element 40, where it is diffused in the planar direction by the vapor chamber 30. Thus, despite its thin design, the temperature control module 1A exhibits high cooling performance. Furthermore, when necessary, such as when the ambient temperature is low, current can be passed through the Peltier element 40 in the opposite direction to when the underside is the heat absorption side, thereby causing the underside of the Peltier element 40 to become the heat-generating side, thereby warming the temperature-control target component 50. In this manner, temperature control of the temperature-control target component 50 can be performed.

[0028] <Temperature Control Module Configuration Example 2> Figure 2 is a cross-sectional schematic diagram showing another example of a temperature control module according to this embodiment. The temperature control module 1B shown in Figure 2 has a configuration in which an intervening layer 60 is provided between the Peltier element 40 and the vapor chamber 30. The other configurations are similar to those of the temperature control module 1A. The provision of the intervening layer 60 can improve adhesion between the Peltier element 40 and the vapor chamber 30, reduce thermal resistance between the Peltier element 40 and the vapor chamber 30, and improve heat transfer between the two. The thickness D of the temperature control module 1B is 1 mm or less. Furthermore, the sum of the thickness D4 of the intervening layer 60, the thickness D2 of the vapor chamber 30, and the thickness D3 of the Peltier element 40 is also 1 mm or less. By providing such a thickness, the provision of the intervening layer 60 can prevent the temperature control module 1B from becoming too thick. The thickness of the intervening layer 60 is typically 20 to 200 μm, preferably approximately 35 to 150 μm. When the intervening layer 60 is viewed as part of the Peltier element 40, or when the filler layer 45 and the intervening layer 60 are provided as an integrated unit on the Peltier element 40, it can also be said that the total thickness D3 of the Peltier element and the thickness D2 of the vapor chamber is 1 mm or less. In the temperature control module 1B shown in FIG. 2, the intervening layer 60 is provided directly on the upper surfaces of the electrodes 41 and the filler layer 45 in the Peltier element 40. However, this is not limitative, and the filler layer 45 may also cover the upper surfaces of the electrodes 41, as in the temperature control module 1A shown in FIG. 1, and the intervening layer 60 may be provided on the upper surface of the filler layer 45.

[0029] <Temperature Control Module Configuration Example 3> Figure 3 is a cross-sectional schematic diagram showing another example of a temperature control module according to this embodiment. Similar to the temperature control module 1A, the temperature control module 1C shown in Figure 3 has a configuration in which a first Peltier element 40 is disposed on a portion of one main surface (the bottom surface in Figure 3) of the vapor chamber 30. Additionally, a second Peltier element 70 is disposed over the entire other main surface (the top surface in Figure 3) of the vapor chamber 30. In other words, the area of ​​the second Peltier element 70 in a plan view is equal to or greater than the area of ​​the vapor chamber 30. Similar to the first Peltier element 40, the second Peltier element 70 includes a thermoelectric conversion layer 78 including a plurality of P-type thermoelectric conversion elements 73 and a plurality of N-type thermoelectric conversion elements 74, a first connection electrode 71, a second connection electrode 72, an insulator layer 76, a filler layer 75, and a coating layer 77.

[0030] In the temperature control module 1C, by applying electricity to the second Peltier element 70 so that the surface facing the vapor chamber 30 is the heat absorption side and the opposite surface is the heat dissipation side, heat diffused by the vapor chamber 30 can be absorbed from the bottom side of the second Peltier element 70 and dissipated from the top side. This further enhances the cooling performance of the temperature control module 1C. The thickness D of the temperature control module 1C is 1 mm or less, and the sum of the thickness D31 of the first Peltier element 40, the thickness D2 of the vapor chamber 30, and the thickness D32 of the second Peltier element 70 is 1 mm or less. By setting these thicknesses, the temperature control module 1C can be prevented from becoming thicker even when the second Peltier element 70 is provided. In the temperature control module 1C, an intervening layer may be provided between the Peltier element 40 and the vapor chamber 30 or between the vapor chamber 30 and the Peltier element 70.

[0031] <Temperature Control Module Configuration Example 4> FIG. 4 is a cross-sectional schematic diagram showing another example of a temperature control module according to this embodiment. The temperature control module 1D shown in FIG. 4 has a configuration in which the first Peltier element 40 is removed from the temperature control module 1C. Specifically, the temperature control module 1D has a Peltier element 70 disposed over the entirety of one main surface (the upper surface in FIG. 4 ) of the vapor chamber 30. In the temperature control module 1D, the temperature-controlled object 50 is brought into contact with the lower surface of the vapor chamber 30, thereby diffusing heat in the planar direction through the vapor chamber 30. In addition, by energizing the Peltier element 70, heat emitted from the vapor chamber 30 can be absorbed from the lower surface of the Peltier element 70 and dissipated to the upper surface. The thickness D of the temperature control module 1D is 1 mm or less, and the sum of the Peltier element thickness D3 and the vapor chamber thickness D2 is 1 mm or less.

[0032] <Configuration Example 5 of Temperature Control Module> FIG. 5 is a schematic cross-sectional view showing another example of a temperature control module according to this embodiment, and FIG. 6 is a bottom view thereof. The cross section taken along line V-V in FIG. 6 corresponds to the cross-sectional view of FIG. 5. The temperature control module 1E shown in FIGS. 5 and 6 has a region (planned installation region) 32 on the underside of the vapor chamber 30 where the temperature-control target component 50 is to be installed. Furthermore, the temperature control module 1E has a configuration in which multiple third Peltier elements 80 are arranged in a region other than the planned installation region 32 on the underside of the vapor chamber 30. In other words, the temperature control module of this configuration example includes a Peltier element and a vapor chamber stacked on the Peltier element, and one or more, preferably multiple, Peltier elements are arranged in a region of the vapor chamber surface where the temperature-control target component is to be installed, different from the planned installation region of the temperature-control target component. The temperature control module of this configuration example has multiple (two in the examples of FIGS. 5 and 6 ) third Peltier elements 80 arranged in an area of ​​the other main surface of the vapor chamber 30 of the temperature control module 1D where the temperature-controlled member 50 is not provided, and can be said to have a configuration in which the second Peltier element 70 has been removed from the temperature control module 1D. In the temperature control module 1E, the third Peltier element 80 is installed in a position corresponding to the area where the vaporized working fluid becomes vapor and flows through the vapor flow path 31 in the configuration example of the vapor chamber described below. Heat radiated from the vaporized working fluid through the second sheet 20 of the vapor chamber can be absorbed from the upper surface of the third Peltier element 80 and radiated to the lower surface. The Peltier element 80 has first and second connection electrodes 81, 82, a P-type thermoelectric conversion element 83, an N-type thermoelectric conversion element 84, a filler layer 85, an insulator layer 86, a coating layer 87, and a thermoelectric conversion layer 88. These are similar to the Peltier element 40 described above, and therefore detailed description thereof will be omitted.

[0033] From the perspective of keeping the total thickness of the Peltier element and vapor chamber at 1 mm or less, or keeping the thickness of the temperature control module at 1 mm or less, it is preferable for the temperature control module to have only one vapor chamber 30 and one Peltier element 40, as in Configuration Examples 1, 2, and 4. This configuration reduces the number of components compared to a configuration in which two or more vapor chambers 30 or Peltier elements 40 are included, as in the temperature control module 1C, making it easier to achieve a thinner design. Therefore, even if the vapor chamber 30 or Peltier element has a thickness exceeding 350 μm, for example, it is easy to keep the total thickness of the Peltier element and vapor chamber, or the thickness of the temperature control module, at 1 mm or less. Furthermore, as in Configuration Example 5, when the Peltier element is disposed in an area of ​​the other main surface of the vapor chamber of the temperature control module where no temperature-controlled component is provided, the Peltier element is positioned at the same level as the temperature-controlled component in the thickness direction of the temperature control module. This is preferable because the Peltier element does not increase the total thickness of the temperature control module and the temperature control component.

[0034] <Configuration Example of Vapor Chamber> Next, a configuration example of the vapor chamber provided in the temperature control modules 1A to 1E will be described. As shown in FIGS. 1 to 5, the vapor chamber 30 includes a first sheet 10 and a second sheet 20. As described above, the first sheet 10 and the second sheet 20 each have a plurality of ridges formed at corresponding positions. FIG. 7 is a plan view schematic diagram showing an example of the first sheet 10 of the vapor chamber 30, in which the vapor chamber 30 is rectangular. The cross section taken along line II in FIG. 7 corresponds to the cross section of the vapor chamber 30 shown in FIGS. 1 to 4. The cross section taken along line VV in FIG. 7 corresponds to the cross section of the vapor chamber 30 shown in FIG. 5. In Figure 7, the contact positions of the first Peltier element 40, which contacts the vapor chamber 30 directly or via an intervening layer as shown in Figures 1 to 3, the temperature-controlled member 50 shown in Figures 4 and 5, and the third Peltier element 80 shown in Figures 5 and 6 are indicated by dashed lines. As shown in Figure 7, the peripheral edge 11 of the first sheet 10 is an annular ridge, and multiple grooves 14 are formed along the peripheral edge 11 on the upper surface of the peripheral edge 11 (the surface facing the second sheet 20). Multiple ridges 13 are formed inside the peripheral edge 11, and recesses 12 are formed between the peripheral edge 11 and the ridges 13 and between adjacent pairs of ridges 13. Each ridge 13 has multiple grooves 15 formed along the ridges 13. An inlet-forming portion 18 protruding from the peripheral edge 11 is provided at the end of the first sheet 10. The inlet-forming portion 18 constitutes a part of the inlet for introducing the working fluid. Furthermore, groove-shaped liquid communication openings 16 are provided at predetermined intervals on the upper surface of the peripheral edge portion 11 so as to intersect with the grooves 14, and groove-shaped liquid communication openings 17 are provided at predetermined intervals on the upper surface of the ridge 13 in a direction intersecting with the grooves 15. In Figure 7, the grooves 14, 15 and the liquid communication openings 16, 17 are simply shown by solid lines.

[0035] The second sheet 20 has a peripheral edge 21 and multiple ridges 23 that have the same configuration as the first sheet 10, except that grooves 14, 15 are not provided in positions corresponding to the peripheral edge 11 and multiple ridges 13 of the first sheet 10 (see FIGS. 1 to 4 ). Recesses 22 are formed between the peripheral edge 21 and the ridges 23 and between adjacent pairs of ridges 23. In addition, an injection port forming portion having a recess is provided at a position corresponding to the injection port forming portion 18 of the first sheet 10 so as to communicate with the space between the peripheral edge 21 of the second sheet 20 and the multiple ridges 23. By joining the first sheet 10 and the second sheet 20, an injection port 24 for injecting the working fluid is formed. The first sheet 10 and the second sheet 20 are joined by diffusion bonding, brazing, or the like so that the peripheral edge 11 and the multiple ridges 13 of the first sheet 10 overlap the peripheral edge 21 and the multiple ridges 23 of the second sheet 20, thereby forming a sealed space 31 surrounded by the ridges 13, 23 and the peripheral edges 11, 21. A working fluid is then sealed in the sealed space 31. This sealed space 31 functions as a vapor flow path, as will be described later. To seal the working fluid, a vacuum is drawn through the injection port 24 to reduce the pressure in the sealed space 31, and then the working fluid is injected through the injection port 24. After the injection is complete, the injection port 24 is sealed by laser welding or crimping.

[0036] When the temperature-controlled component 50, which is a heat source, or the Peltier element 40 that is in contact with the heat source and radiates heat to the outside (hereinafter collectively referred to as the "heat source") comes into contact with a predetermined portion of the vapor chamber 30, the heat is transferred by thermal conduction within the first sheet 10, and the condensate present in a position close to the heat source within the sealed space is heated. The condensate absorbs the heat and evaporates, thereby cooling the heat source. The evaporated working fluid becomes vapor and moves within the vapor flow path 31 as indicated by the black arrows in FIG. 7. Because this flow occurs in a direction away from the heat source, the vapor moves in a direction away from the heat source. The vapor within the vapor flow path 31 moves away from the heat source toward the periphery of the vapor chamber 30, which has a relatively low temperature. During this movement, heat is absorbed by the first sheet 10 and the second sheet 20, and the vapor is cooled. The first sheet 10 and the second sheet 20 absorb heat from the steam and release it to the outside air from their undersides (the surfaces opposite the surfaces (upper surfaces) where the first sheet 10 and the second sheet 20 face each other) and sides. The working fluid absorbs heat while moving through the steam flow path 31 and condenses to a liquid. This condensate adheres to the wall surfaces of the steam flow path 31. Meanwhile, because steam flows continuously through the steam flow path 31, the condensate is distributed and moves from the liquid communication openings 16, 17, etc. to the grooves 14, 15 that serve as condensate flow paths, as if being pushed by the steam. The condensate that enters the grooves 14, 15 that serve as condensate flow paths moves toward the heat source, as indicated by the thin white arrows in FIG. 7, due to capillary action caused by the condensate flow path and pressure from the steam. It then vaporizes again due to heat from the heat source, repeating the above-described operation and state change. The vapor chamber 30, with its strong capillary force in the condensate flow path, effectively returns the condensate, achieving a high heat transport capacity despite its thin design. Therefore, the temperature control module obtained by stacking the Peltier elements 40, 70, and 80 on the vapor chamber 30 exhibits high cooling capacity.

[0037] To form ridges or grooves on the first sheet 10 and the second sheet 20, for example, a method can be used in which material is removed to a predetermined depth by half-etching a metal sheet having a corresponding outer size.

[0038] The cross-sectional shape of the ridges is not limited to flat shapes with vertical sides as shown in FIGS. 1 to 5 , but can be any shape, such as a trapezoid or a shape with curved sides. The cross-sectional shape of the recesses is not limited to horizontal shapes with vertical walls as shown in FIGS. 1 to 5 , but can be any shape, such as a semicircular or elliptical bottom, or a semicircular or elliptical bottom and wall. The width, length, height, depth, etc. of the ridges and recesses are not particularly limited and can be appropriately set so that the vapor chamber operates smoothly. The configuration of the ridges on the first sheet and the second sheet may differ other than the presence or absence of grooves, and grooves may also be formed in the ridges on the second sheet. The width, depth, length, cross-sectional shape, etc. of the grooves that form the condensate flow paths and liquid communication openings can be variously changed. Furthermore, the arrangement interval, arrangement pattern (linear, oblique, zigzag, etc.), and shape of the liquid communication openings are also arbitrary. The thickness of the vapor chamber is preferably 500 μm or less, more preferably 400 μm or less, and even more preferably 350 μm or less. The lower limit of the thickness of the vapor chamber is usually about 100 μm. In other words, the thickness of the vapor chamber is preferably 100 to 500 μm.

[0039] Next, the materials and the like of each part constituting the Peltier element will be described.

[0040] [Thermoelectric Conversion Element] The thermoelectric conversion element used in the Peltier element contains a thermoelectric semiconductor material. The thermoelectric semiconductor material is usually sintered to obtain a Peltier element. The thermoelectric conversion element is preferably a sintered body of a coating film formed by applying a composition containing a thermoelectric semiconductor material (hereinafter also referred to as a "composition containing a thermoelectric semiconductor material" or a "thermoelectric semiconductor composition") to the surface of a support or the like. When the thermoelectric conversion element is a sintered body of a coating film of the thermoelectric semiconductor composition, a sheet-shaped thermoelectric conversion module can be easily manufactured, and a thermoelectric conversion element with improved flexibility can also be easily obtained. The thickness of the thermoelectric conversion element is preferably 10 μm or more, more preferably 25 μm or more, even more preferably 35 μm or more, and preferably 800 μm or less, more preferably 500 μm or less, and even more preferably 300 μm or less. In other words, the thickness of the thermoelectric conversion element is preferably 10 to 800 μm. When the thickness of the thermoelectric conversion element is within the above range, it is easy to produce a thermoelectric conversion element that exhibits good thermoelectric conversion performance with good productivity.

[0041] <Thermoelectric Semiconductor Composition> The thermoelectric semiconductor composition used to produce the thermoelectric conversion layer contains at least a thermoelectric semiconductor material, preferably contains thermoelectric semiconductor particles made of the thermoelectric semiconductor material and a resin, and more preferably contains thermoelectric semiconductor particles, a polymer component, and an ionic compound. The ionic compound preferably contains at least one of an ionic liquid and an inorganic ionic compound, and more preferably contains an ionic liquid.

[0042] (Thermoelectric Semiconductor Material) The thermoelectric semiconductor material contained in the P-type thermoelectric semiconductor element and the N-type thermoelectric semiconductor element is not particularly limited as long as it is a material that can generate thermoelectric power by applying a temperature difference. For example, bismuth-tellurium-based thermoelectric semiconductor materials such as P-type bismuth telluride and N-type bismuth telluride; telluride-based thermoelectric semiconductor materials such as GeTe and PbTe; antimony-tellurium-based thermoelectric semiconductor materials; ZnSb, Zn ３ Sb ２ , Zn ４ Sb ３ Zinc-antimony based thermoelectric semiconductor materials such as silicon-germanium based thermoelectric semiconductor materials such as silicon germanium; Bi ２ Se ３Bismuth selenide-based thermoelectric semiconductor materials such as β-FeSi ２ , CrSi ２ , MnSi １．７３ , Mg ２ Silicide-based thermoelectric semiconductor materials such as Si; oxide-based thermoelectric semiconductor materials; Heusler materials such as FeVAl, FeVAlSi, and FeVTiAl; TiS ２ Examples of suitable thermoelectric semiconductor materials include sulfide-based thermoelectric semiconductor materials such as tungsten, skutterudite materials, and carbon materials such as carbon nanotubes (CNTs). Among these, bismuth-tellurium-based thermoelectric semiconductor materials, telluride-based thermoelectric semiconductor materials, antimony-tellurium-based thermoelectric semiconductor materials, and bismuth selenide-based thermoelectric semiconductor materials are preferred from the viewpoint of easily achieving high thermoelectric conversion performance. Furthermore, of these, silicide-based thermoelectric semiconductor materials are preferred from the viewpoint of not containing rare metals whose supply is unstable due to geopolitical issues, and skutterudite materials are preferred from the viewpoint of making it easier to operate the thermoelectric conversion module in a high-temperature environment.

[0043] Furthermore, from the viewpoint of high thermoelectric conversion performance in low-temperature environments and ease of matching with the operating temperature range of a vapor chamber in which the boiling point of the working fluid is 150°C or lower, the thermoelectric semiconductor material is preferably a bismuth-tellurium-based thermoelectric semiconductor material such as P-type bismuth telluride or N-type bismuth telluride. In this case, the temperature control module may be such that the Peltier element is provided with a thermoelectric conversion layer including a plurality of thermoelectric conversion elements, and the plurality of thermoelectric conversion elements include a bismuth-tellurium compound. Note that, when using a vapor chamber in which the boiling point of the working fluid is higher than 150°C, it is preferable to use, for example, a silicide-based thermoelectric semiconductor material, a telluride-based thermoelectric semiconductor material such as PbTe, a silicon-germanium-based thermoelectric semiconductor material such as SiGe, or a skutterudite material. P-type bismuth telluride has carriers that are holes and has a positive Seebeck coefficient, for example, Bi Ｘ Te ３ Sb ２－ＸIn this case, X is preferably 0<X≦0.8, and more preferably 0.4≦X≦0.6. When X is greater than 0 and not greater than 0.8, the Seebeck coefficient and electrical conductivity are increased, and the properties as a P-type thermoelectric conversion material are maintained, which is preferable. In addition, N-type bismuth telluride has electrons as carriers and a negative Seebeck coefficient, for example, Bi ２ Te ３－Ｙ Se Ｙ In this case, Y is preferably 0≦Y≦3 (when Y=0: Bi ２ Te ３ ) and more preferably 0.1<Y≦2.7. When Y is 0 or more and 3 or less, the Seebeck coefficient and electrical conductivity become large, and the properties as an N-type thermoelectric conversion material are maintained, which is preferable.

[0044] The thermoelectric semiconductor material used in the thermoelectric conversion layer is preferably in the form of particles having a predetermined size, and is preferably thermoelectric semiconductor particles that have been pulverized to a predetermined size using, for example, a fine pulverizing device such as a ball mill.

[0045] The amount of thermoelectric semiconductor particles in the thermoelectric semiconductor composition is preferably 30 to 99% by mass, more preferably 50 to 96% by mass, and even more preferably 70 to 95% by mass. When the amount of thermoelectric semiconductor particles is within the above range, the Seebeck coefficient (absolute value of the Peltier coefficient) is large, and the decrease in electrical conductivity is suppressed, with only the thermal conductivity decreasing, so that a film exhibiting high thermoelectric performance, sufficient film strength, and appropriate flexibility can be obtained, which is preferable.

[0046] The average particle size of the thermoelectric semiconductor particles is preferably 10 nm to 200 μm, more preferably 10 nm to 30 μm, even more preferably 50 nm to 10 μm, and particularly preferably 1 to 6 μm. Within the above ranges, uniform dispersion is facilitated, and electrical conductivity can be increased. The method for pulverizing a thermoelectric semiconductor material to obtain thermoelectric semiconductor particles is not particularly limited, and the material may be pulverized to a predetermined size using a known fine pulverizing device such as a jet mill, ball mill, bead mill, colloid mill, conical mill, disk mill, edge mill, flour mill, hammer mill, pellet mill, Willy mill, or roller mill. In this specification, the average particle size of the thermoelectric semiconductor particles is measured using a laser diffraction particle size analyzer (Model 1064, manufactured by CILAS) and is a value represented by the median of the particle size distribution.

[0047] Furthermore, it is preferable that the thermoelectric semiconductor particles have been heat-treated in advance (the "heat treatment" referred to here is different from the "annealing treatment" performed in the annealing treatment step referred to in the present invention). Heat treatment improves the crystallinity of the thermoelectric semiconductor particles and also removes the surface oxide film of the thermoelectric semiconductor particles, thereby increasing the Seebeck coefficient (absolute value of the Peltier coefficient) of the thermoelectric semiconductor material and further improving the thermoelectric figure of merit. The heat treatment is not particularly limited, but is preferably performed before preparing the thermoelectric semiconductor composition in an inert gas atmosphere such as nitrogen or argon, a reducing gas atmosphere such as hydrogen, or under vacuum conditions with a controlled gas flow rate, so as not to adversely affect the thermoelectric semiconductor particles. It is more preferable to perform the heat treatment in a mixed gas atmosphere of an inert gas and a reducing gas. The specific temperature conditions depend on the thermoelectric semiconductor particles used, but it is usually preferable to perform the heat treatment at a temperature below the melting point of the particles, at 100 to 1,500°C, for several minutes to several tens of hours.

[0048] (Polymer Component) The polymer component that can be contained in the thermoelectric semiconductor composition has the effect of physically bonding the thermoelectric semiconductor material (thermoelectric semiconductor particles) together, and facilitates the formation of a thin film by coating, etc., for the Peltier element, which is a thermoelectric conversion module. The polymer component is preferably a heat-resistant resin or a binder resin.

[0049] The heat-resistant resin maintains its various physical properties, such as mechanical strength and thermal conductivity, without being impaired when a thin film made of the thermoelectric semiconductor composition is annealed to cause crystal growth of thermoelectric semiconductor particles. The heat-resistant resin is preferably a polyamide resin, a polyamideimide resin, a polyimide resin, or an epoxy resin, because it has higher heat resistance and does not adversely affect the crystal growth of thermoelectric semiconductor particles in the thin film, and more preferably a polyamide resin, a polyamideimide resin, or a polyimide resin because it has excellent flexibility.

[0050] The heat-resistant resin preferably has a decomposition temperature of 300° C. or higher. If the decomposition temperature is within the above range, the resin will not lose its function as a binder and will be able to maintain flexibility even when a thin film made of the thermoelectric semiconductor composition is annealed, as will be described later.

[0051] The heat-resistant resin preferably has a mass loss rate of 10% or less, more preferably 5% or less, and even more preferably 1% or less, at 300° C. as measured by thermogravimetry (TG). If the mass loss rate is within the above range, the resin will not lose its function as a binder and the flexibility of the thermoelectric semiconductor material chip can be maintained, even when a thin film made of the thermoelectric semiconductor composition is annealed, as described below.

[0052] The content of the heat-resistant resin in the thermoelectric semiconductor composition is 0.1 to 40% by mass, preferably 0.5 to 20% by mass, more preferably 1 to 20% by mass, and even more preferably 2 to 15% by mass. When the content of the heat-resistant resin is within the above range, it functions as a binder for the thermoelectric semiconductor material, making it easier to form a thin film, and a film that achieves both high thermoelectric performance and film strength is obtained, and a resin portion is present on the outer surface of the chip of the thermoelectric semiconductor material.

[0053] The binder resin also facilitates the separation from the substrate, such as glass, alumina, or silicon, used in the production of the thermoelectric conversion element after the annealing treatment described below.

[0054] The binder resin refers to a resin that decomposes at 90% by mass or more at the baking (annealing) temperature or higher, more preferably at 95% by mass or more, and particularly preferably at 99% by mass or more. Furthermore, a resin that maintains various physical properties, such as mechanical strength and thermal conductivity, is more preferred when a coating (thin film) made of the thermoelectric semiconductor composition is baked (annealed) to cause crystal growth of thermoelectric semiconductor particles. When a resin that decomposes at 90% by mass or more at the baking (annealing) temperature or higher, i.e., a resin that decomposes at a temperature lower than the heat-resistant resin described above, is used as the binder resin, the binder resin decomposes upon baking, reducing the content of the binder resin, which serves as an insulating component in the baked body, and promoting crystal growth of thermoelectric semiconductor particles in the thermoelectric semiconductor composition. This reduces voids in the thermoelectric semiconductor material layer and improves the filling rate. Whether or not a resin decomposes to a predetermined extent (e.g., 90% by mass) at or above the baking (annealing) temperature is determined by measuring the mass loss rate (the value obtained by dividing the mass after decomposition by the mass before decomposition) at the baking (annealing) temperature by thermogravimetry (TG).

[0055] Thermoplastic resins and curable resins can be used as such binder resins. Examples of thermoplastic resins include polyolefin resins such as polyethylene, polypropylene, polyisobutylene, and polymethylpentene; polycarbonate; thermoplastic polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polyvinyl polymers such as polystyrene, acrylonitrile-styrene copolymer, polyvinyl acetate, ethylene-vinyl acetate copolymer, vinyl chloride, polyvinylpyridine, polyvinyl alcohol, and polyvinylpyrrolidone; polyurethane; and cellulose derivatives such as ethyl cellulose. Examples of curable resins include thermosetting resins and photocurable resins. Examples of thermosetting resins include epoxy resins and phenolic resins. Examples of photocurable resins include photocurable acrylic resins, photocurable urethane resins, and photocurable epoxy resins. These resins may be used alone or in combination of two or more. Among these, from the viewpoint of the electrical resistivity of the thermoelectric semiconductor material in the thermoelectric conversion layer, thermoplastic resins are preferred, polycarbonate and cellulose derivatives such as ethyl cellulose are more preferred, and polycarbonate is particularly preferred.

[0056] The binder resin is appropriately selected depending on the temperature of the firing (annealing) treatment of the thermoelectric semiconductor material in the firing (annealing) treatment step. From the viewpoint of the electrical resistivity of the thermoelectric semiconductor material in the thermoelectric conversion layer, firing (annealing) at a temperature equal to or higher than the final decomposition temperature of the binder resin is preferable. In this specification, the "final decomposition temperature" refers to the temperature at which the mass loss rate at the firing (annealing) temperature measured by thermogravimetry (TG) is 100% (the mass after decomposition is 0% of the mass before decomposition).

[0057] The final decomposition temperature of the binder resin is usually 150 to 600° C., preferably 200 to 560° C., more preferably 220 to 460° C., and particularly preferably 240 to 360° C. If a binder resin having a final decomposition temperature within this range is used, it functions as a binder for the thermoelectric semiconductor material, facilitating the formation of a thin film during printing.

[0058] The content of the binder resin in the thermoelectric semiconductor composition is 0.1 to 40 mass%, preferably 0.5 to 20 mass%, more preferably 0.5 to 10 mass%, and particularly preferably 0.5 to 5 mass%. When the content of the binder resin is within the above range, the electrical resistivity of the thermoelectric semiconductor material in the thermoelectric conversion layer can be reduced.

[0059] The content of the binder resin in the thermoelectric semiconductor material is preferably 0 to 10% by mass, more preferably 0 to 5% by mass, and particularly preferably 0 to 1% by mass. If the content of the binder resin in the thermoelectric semiconductor material is within the above range, the electrical resistivity of the thermoelectric semiconductor material in the thermoelectric conversion layer can be reduced.

[0060] (Ionic Liquid) The ionic liquid that can be contained in the thermoelectric semiconductor composition is a molten salt formed by combining a cation and an anion, and refers to a salt that can exist in liquid form at any temperature range from -50°C to less than 400°C. In other words, an ionic liquid is an ionic compound having a melting point in the range of -50°C to less than 400°C. The melting point of the ionic liquid is preferably -25°C to 200°C, more preferably 0°C to 150°C. Ionic liquids have characteristics such as extremely low vapor pressure and nonvolatility, excellent thermal stability and electrochemical stability, low viscosity, and high ionic conductivity. Therefore, as a conductive additive, they can effectively suppress a decrease in electrical conductivity between thermoelectric semiconductor materials. Furthermore, ionic liquids exhibit high polarity due to their aprotic ionic structure and excellent compatibility with heat-resistant resins, thereby enabling the electrical conductivity of thermoelectric semiconductor materials to be uniform.

[0061] The ionic liquid may be a known or commercially available one. For example, a nitrogen-containing cyclic cationic compound such as pyridinium, pyrimidinium, pyrazolium, pyrrolidinium, piperidinium, or imidazolium, or a derivative thereof; a tetraalkylammonium-based amine-based cation and a derivative thereof; a phosphine-based cation such as phosphonium, trialkylsulfonium, or tetraalkylphosphonium, or a derivative thereof; a lithium cation and a derivative thereof; or a mixture of a cation component and Cl － ,Br －, I － , AlCl ４ － , Al ２ Cl ７ － , B.F. ４ － , P.F. ６ － , ClO ４ － , NO ３ － , C.H. ３ COO － , C.F. ３ COO － , C.H. ３ SO ３ － , C.F. ３ SO ３ － , (FSO ２ ) ２ N － , (CF ３ SO ２ ) ２ N － , (CF ３ SO ２ ) ３ C － , AsF ６ － , SbF ６ － , NbF ６ － , TaF ６ － , F(HF) ｎ － , (CN) ２ N － , C ４ F ９ SO ３ － , (C ２ F ５ SO ２ ) ２ N － , C ３ F ７ COO － , (CF ３ SO ２ ) (CF ３ CO)N － and an anion component such as the above.

[0062] Among the above-mentioned ionic liquids, from the viewpoints of high-temperature stability, compatibility with thermoelectric semiconductor materials and resins, suppression of a decrease in the electrical conductivity of the gaps between thermoelectric semiconductor materials, etc., it is preferred that the cationic component of the ionic liquid contains at least one selected from pyridinium cations and derivatives thereof, and imidazolium cations and derivatives thereof.

[0063] Specific examples of ionic liquids in which the cationic component contains a pyridinium cation and a derivative thereof include 4-methyl-butylpyridinium chloride, 3-methyl-butylpyridinium chloride, 4-methyl-hexylpyridinium chloride, 3-methyl-hexylpyridinium chloride, 4-methyl-octylpyridinium chloride, 3-methyl-octylpyridinium chloride, 3,4-dimethyl-butylpyridinium chloride, 3,5-dimethyl-butylpyridinium chloride, 4-methyl-butylpyridinium tetrafluoroborate, 4-methyl-butylpyridinium hexafluorophosphate, 1-butylpyridinium bromide, 1-butyl-4-methylpyridinium bromide, 1-butyl-4-methylpyridinium hexafluorophosphate, etc. Among these, 1-butyl-4-methylpyridinium bromide, 1-butylpyridinium bromide, and 1-butyl-4-methylpyridinium hexafluorophosphate are preferred.

[0064] Specific examples of ionic liquids in which the cationic component contains an imidazolium cation and a derivative thereof include [1-butyl-3-(2-hydroxyethyl)imidazolium bromide], [1-butyl-3-(2-hydroxyethyl)imidazolium tetrafluoroborate], 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium bromide, 1-butyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium chloride, 1-octyl-3-methylimidazolium chloride, 1-decyl-3-methylimidazolium chloride, and 1-decyl-3-methylimidazolium chloride. Examples of the imidazolium bromide include imidazolium bromide, 1-dodecyl-3-methylimidazolium chloride, 1-tetradecyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-hexyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-methyl-3-butylimidazolium methyl sulfate, and 1,3-dibutylimidazolium methyl sulfate. Among these, 1-butyl-3-(2-hydroxyethyl)imidazolium bromide and 1-butyl-3-(2-hydroxyethyl)imidazolium tetrafluoroborate are preferred.

[0065] The above ionic liquid has an electrical conductivity of 10 －７ If the ionic conductivity is in the above range, the conductive additive can effectively suppress a decrease in the electrical conductivity between the thermoelectric semiconductor materials.

[0066] The ionic liquid preferably has a decomposition temperature of 300° C. or higher. If the decomposition temperature is within the above range, the effect as a conductive additive can be maintained even when a thin film made of the thermoelectric semiconductor composition is annealed, as will be described later.

[0067] Furthermore, the ionic liquid preferably has a mass loss rate of 10% or less, more preferably 5% or less, and even more preferably 1% or less at 300° C. as measured by thermogravimetry (TG). If the mass loss rate is within the above range, the ionic liquid can maintain its effectiveness as a conductive additive even when a thin film made of the thermoelectric semiconductor composition is annealed, as described below.

[0068] The amount of the ionic liquid in the thermoelectric semiconductor composition is preferably 0.01 to 50% by mass, more preferably 0.5 to 30% by mass, and even more preferably 1.0 to 20% by mass. When the amount of the ionic liquid is within the above range, a decrease in electrical conductivity is effectively suppressed, and a film with high thermoelectric performance is obtained.

[0069] (Inorganic ionic compound) The inorganic ionic compound that can be contained in the thermoelectric semiconductor composition is a compound composed of at least a cation and an anion. Inorganic ionic compounds exist in a solid state over a wide temperature range from 400 to 900°C and have characteristics such as high ionic conductivity, so that they can act as a conductive additive to suppress a decrease in electrical conductivity between thermoelectric semiconductor materials.

[0070] The cation constituting the inorganic ionic compound is a metal cation. Examples of the metal cation include alkali metal cations, alkaline earth metal cations, typical metal cations, and transition metal cations, and alkali metal cations or alkaline earth metal cations are more preferred. Examples of the alkali metal cation include Li ＋ , Na ＋ , K. ＋ , Rb ＋ , Cs ＋ and Fr ＋ Examples of alkaline earth metal cations include Mg ２＋ , Ca ２＋ , Sr ２＋ and Ba ２＋ etc.

[0071] Examples of the anion constituting the inorganic ionic compound include F － , Cl － ,Br － , I－ , O.H. － , C.N. － , NO ３ － , NO ２ － , ClO － , ClO ２ － , ClO ３ － , ClO ４ － , CrO ４ ２－ , HSO ４ － , SCN － , B.F. ４ － , P.F. ６ － etc.

[0072] The inorganic ionic compound contained in the thermoelectric conversion layer may be a known or commercially available one. For example, a cationic component such as potassium cation, sodium cation, or lithium cation and a Cl － , AlCl ４ － , Al ２ Cl ７ － , ClO ４ － chloride ions such as Br － bromide ions such as I － Iodide ions such as BF ４ － , P.F. ６ － Fluoride ions such as F(HF) ｎ － Halide anions such as NO ３ － , O.H. － , C.N. － and an anion component such as the above.

[0073] Among the above inorganic ionic compounds, from the viewpoints of high-temperature stability, compatibility with thermoelectric semiconductor materials and resins, and suppression of a decrease in the electrical conductivity of the gaps between thermoelectric semiconductor materials, it is preferable that the cation component of the inorganic ionic compound contains at least one selected from potassium, sodium, and lithium. Also, it is preferable that the anion component of the inorganic ionic compound contains a halide anion, and Cl － ,Br － , and I － It is more preferable that the composition contains at least one selected from the following:

[0074] Specific examples of inorganic ionic compounds in which the cationic component contains potassium cations include KBr, KI, KCl, KF, KOH, and K ２ CO ３ Among these, KBr and KI are preferred. Specific examples of inorganic ionic compounds whose cationic component contains a sodium cation include NaBr, NaI, NaOH, NaF, and Na ２ CO ３ Among these, NaBr and NaI are preferred. Specific examples of inorganic ionic compounds whose cationic component contains lithium cations include LiF, LiOH, and LiNO. ３ Among these, LiF and LiOH are preferred.

[0075] The inorganic ionic compound has an electrical conductivity of 10 －７ S / cm or more, and －６ If the electrical conductivity is in the above range, the conductive additive can effectively suppress a decrease in electrical conductivity between thermoelectric semiconductor materials.

[0076] The inorganic ionic compound preferably has a decomposition temperature of 400° C. or higher. If the decomposition temperature is within the above range, the effect as a conductive additive can be maintained even when a thin film made of the thermoelectric semiconductor composition is annealed, as will be described later.

[0077] Furthermore, the inorganic ionic compound preferably has a mass loss rate of 10% or less, more preferably 5% or less, and even more preferably 1% or less, at 400° C. as measured by thermogravimetry (TG). If the mass loss rate is within the above range, the compound can easily maintain its effect as a conductive additive even when a thin film made of the thermoelectric semiconductor composition is annealed, as described below.

[0078] The amount of inorganic ionic compound in the thermoelectric semiconductor composition is preferably 0.01 to 50% by mass, more preferably 0.5 to 30% by mass, and even more preferably 1.0 to 10% by mass. When the amount of inorganic ionic compound is within the above range, a decrease in electrical conductivity can be effectively suppressed, resulting in a film with improved thermoelectric performance. When an inorganic ionic compound and an ionic liquid are used in combination, the total content of the inorganic ionic compound and the ionic liquid in the thermoelectric semiconductor composition is preferably 0.01 to 50% by mass, more preferably 0.5 to 30% by mass, and even more preferably 1.0 to 10% by mass.

[0079] (Method for Preparing Thermoelectric Semiconductor Composition) The method for preparing the thermoelectric semiconductor composition is not particularly limited. The thermoelectric semiconductor composition may be prepared by mixing and dispersing a thermoelectric semiconductor material, a heat-resistant resin, and optionally one or both of an ionic liquid and an inorganic ionic compound, other additives, and a solvent using a known device such as an ultrasonic homogenizer, a spiral mixer, a planetary mixer, a disperser, or a hybrid mixer. A solvent may be used when preparing the thermoelectric semiconductor composition. Examples of solvents that may be used include toluene, ethyl acetate, methyl ethyl ketone, alcohol, tetrahydrofuran, methylpyrrolidone, and ethyl cellosolve. These solvents may be used alone or in combination of two or more. The solids concentration of the thermoelectric semiconductor composition is not particularly limited, as long as the composition has a viscosity suitable for coating.

[0080] [Method of Manufacturing Temperature Control Module] As an example of a method of manufacturing a temperature control module, a method of manufacturing a temperature control module having a Peltier element in which a thermoelectric conversion element is formed by a coating method will be described. Note that this manufacturing method shows an example in which an adhesive layer is formed so as to cover the connection electrodes on the main surface facing the vapor chamber, and the Peltier element is attached to the vapor chamber by this adhesive layer (that is, this corresponds to the embodiment in which the adhesive layer also serves as filler layers 45, 75, 85 in temperature control modules 1A, 1C to 1E shown in Figures 1 and 3 to 5, and also corresponds to the embodiment in which the adhesive layer also serves as intervening layer 60 and filler layer 45 in temperature control module 1B shown in Figure 2).

[0081] <Formation of Thermoelectric Conversion Element> When producing a temperature control module having a coating-type Peltier element, the thermoelectric conversion element is not particularly limited, but can be obtained by, for example, applying the thermoelectric semiconductor composition to a substrate such as glass, alumina, silicon, or a resin film, or to a substrate on which a sacrificial layer (described later) is formed, obtaining a coating film, drying the film, and appropriately separating the film from the substrate. By forming the thermoelectric conversion element in this manner, a large number of thermoelectric conversion elements can be obtained easily and at low cost. The resin film is preferably heat-resistant, and films made of polyamide resin, polyamideimide resin, polyimide resin, etc. are preferred.

[0082] Methods for applying a thermoelectric semiconductor composition to form a coating film include, but are not limited to, well-known methods such as screen printing, flexographic printing, gravure printing, spin coating, dip coating, die coating, spray coating, bar coating, and doctor blade coating. When forming a patterned coating film, methods such as screen printing and slot die coating, which allow for easy pattern formation using a screen plate with a desired pattern, are preferably used. The resulting coating film is then dried to form a thermoelectric conversion element. Conventional drying methods, such as hot air drying, hot roll drying, and infrared irradiation, can be used. The heating temperature is typically 80 to 150°C, and the heating time varies depending on the heating method, but is typically several seconds to several tens of minutes.

[0083] When a solvent is used in preparing the thermoelectric semiconductor composition, the heating temperature is not particularly limited as long as it is within a temperature range that allows the solvent used to be dried.

[0084] The thickness of the coating film made of the thermoelectric semiconductor composition is not particularly limited, but from the viewpoints of thermoelectric performance and film strength, and of making the Peltier element thinner, it is preferably 100 nm to 1,000 μm, more preferably 300 nm to 600 μm, and even more preferably 5 to 400 μm.

[0085] The coating film of the thermoelectric semiconductor composition is preferably further annealed to form a fired body. Annealing stabilizes the thermoelectric performance and promotes crystal growth of the thermoelectric semiconductor particles in the thin film, further improving the thermoelectric performance. The annealing is not particularly limited, but is typically performed under a controlled gas flow rate in an inert gas atmosphere such as nitrogen or argon, a reducing gas atmosphere, or under vacuum conditions. Depending on the heat resistance temperature of the resin and ionic compound used, the annealing is performed at 100 to 500°C for several minutes to several tens of hours. Furthermore, during the annealing, the thermoelectric semiconductor composition may be pressed to increase the density of the thermoelectric semiconductor composition.

[0086] The sacrificial layer can be made of a resin such as polymethyl methacrylate or polystyrene, or a release agent such as a fluorine-based release agent or a silicone-based release agent. The use of the sacrificial layer allows the thermoelectric conversion element formed on a substrate such as glass to be easily peeled off from the glass or the like after annealing. The formation of the sacrificial layer is not particularly limited, and can be performed by a known method such as flexographic printing or spin coating.

[0087] <Filling of insulator> In order to ensure insulation between the obtained thermoelectric conversion elements, an insulator is filled between the thermoelectric conversion elements. The insulator ensures insulation between the P-type thermoelectric conversion elements and the N-type thermoelectric conversion elements, and between the P-type thermoelectric conversion elements themselves or between the N-type thermoelectric conversion elements themselves, and also serves as a reinforcing material that allows the mechanical strength to be maintained when the elements are integrated. There are no particular limitations on the insulator as long as it can maintain insulation and strength, and examples include insulating resins, ceramics, etc.

[0088] Examples of insulating resins include polyimide resins, silicone resins, rubber resins, acrylic resins, olefin resins, maleimide resins, and epoxy resins. From the viewpoints of heat resistance and mechanical strength, the insulating resin is preferably selected from polyimide resins, silicone resins, acrylic resins, maleimide resins, and epoxy resins. The insulating resin is preferably a curable resin or a foamable resin. The insulating resin may further contain a filler. The filler is preferably a hollow filler. The hollow filler is not particularly limited and any known hollow filler can be used. Examples include inorganic hollow fillers such as glass balloons, silica balloons, shirasu balloons, fly ash balloons, and metal silicates, as well as organic hollow fillers such as acrylonitrile, vinylidene chloride, phenolic resins, epoxy resins, and urea resins. The use of hollow fillers reduces the thermal conductivity of the insulating resin, further improving thermoelectric performance. Examples of ceramics include materials containing aluminum oxide (alumina), aluminum nitride, zirconium oxide (zirconia), silicon carbide, etc. as their main components (50 mass % or more of the ceramics). In addition to the above main components, for example, rare earth compounds can also be added.

[0089] The insulator filling method can be performed by a known method. For example, a liquid resin is used, and the resin is spread and filled using a coating member such as a squeegee on the surface of a support on which chips of P-type thermoelectric semiconductor material and chips of N-type thermoelectric semiconductor material are alternately arranged. Alternatively, the resin is dripped from approximately the center of the support to the outside and then filled by spin coating. Furthermore, the support is immersed in a liquid resin reservoir or the like and then lifted up to fill. Furthermore, a sheet-like insulating resin is used, and the sheet-like insulating resin is attached to the surface of the support on which chips of P-type thermoelectric semiconductor material and chips of N-type thermoelectric semiconductor material are alternately arranged, and the sheet-like insulating resin is melted and filled by heating and / or pressing. After filling, thermal curing or the like is performed.

[0090] The support is not particularly limited, and examples thereof include glass, silicon, ceramics, metal, and plastic. Preferably, the support is selected from glass, plastic, and silicon. When annealing or the like is performed at high temperatures, glass, silicon, ceramics, or metal is preferred. The support is peeled off after obtaining an integrated product of multiple thermoelectric conversion elements and the insulators located between them. The substrate having the sacrificial layer described above can be used as the support, and the thermoelectric conversion elements may be transferred from the substrate having the sacrificial layer to another support.

[0091] <Formation of Connection Electrode> Next, a connection electrode to be used for connecting a pair of thermoelectric conversion elements or for external connection is formed. The connection electrode is preferably formed of at least one film selected from the group consisting of a vapor-deposited film, a plated film, a conductive composition, and a metal foil. The metal material used for the connection electrode is not particularly limited, but examples thereof include copper, gold, nickel, aluminum, rhodium, platinum, chromium, palladium, stainless steel, molybdenum, solder, and an alloy containing any of these metals.

[0092] Examples of methods for forming the connection electrodes include a method in which an unpatterned electrode is provided on the above-mentioned integrated product of a plurality of thermoelectric conversion elements and an insulator layer (hereinafter simply referred to as the "integrated product"), and then processed into a predetermined pattern shape by known physical or chemical treatments, mainly photolithography, or a combination of these, or a method in which an electrode pattern is directly formed by screen printing, inkjet printing, or the like, using a conductive paste made of a conductive composition containing the above-mentioned metal material, etc. Methods for forming unpatterned electrodes include dry processes such as PVD (physical vapor deposition) methods such as vacuum deposition, sputtering, and ion plating, or CVD (chemical vapor deposition) methods such as thermal CVD and atomic layer deposition (ALD), or wet processes such as various coatings and electrodeposition methods, such as dip coating, spin coating, spray coating, gravure coating, die coating, and doctor blade methods, silver halide plating, electrolytic plating, electroless plating, and metal foil lamination, and are selected appropriately depending on the material of the electrode. The metal foil may be laminated by joining it to a thermoelectric material or the like using solder. Since the connecting electrodes are required to have high electrical conductivity and high thermal conductivity in order to maintain thermoelectric performance, it is more preferable to use electrodes formed by plating or vacuum film formation. Vacuum film formation methods such as vacuum deposition and sputtering, as well as electroplating and electroless plating, are preferred because they can easily achieve high electrical conductivity and high thermal conductivity. Depending on the dimensions and dimensional accuracy required for the formed pattern, a pattern can also be easily formed via a hard mask such as a metal mask.

[0093] The thickness of the connection electrode layer is preferably 10 nm to 200 μm, more preferably 30 nm to 150 μm, and even more preferably 50 nm to 120 μm. When the thickness of the connection electrode layer is within the above range, the electrical conductivity is high and the resistance is low, and sufficient strength as a connection electrode is obtained.

[0094] <Formation of Adhesive Layer> An adhesive layer is provided on at least one surface of the Peltier element, which is a thermoelectric conversion module. That is, the adhesive layer is provided on the first connection electrodes, including the gaps between adjacent first connection electrodes. Then, for example, by adhering the Peltier element to a vapor chamber using this adhesive layer, the Peltier element can be easily installed. Furthermore, by including the gaps between the first connection electrodes, weather resistance can be improved. Furthermore, insulation between the vapor chamber and the connection electrodes of the Peltier element can be ensured. The adhesive layer may also be formed on the surface of the vapor chamber in advance.

[0095] The adhesive layer may be any material that can be easily adhered to the vapor chamber, but is not particularly limited thereto. Preferably, the adhesive layer contains an adhesive resin. If desired, the adhesive layer may contain adhesive additives such as crosslinkers, tackifiers, polymerizable compounds, and polymerization initiators, as well as silane coupling agents, antistatic agents, antioxidants, UV absorbers, light stabilizers, softeners, fillers, refractive index adjusters, and colorants. Among these, boron nitride fillers, alumina fillers, and the like may be used as fillers to improve the thermal conductivity of the adhesive layer and reduce the thermal resistance between the Peltier element 40 and the vapor chamber 30. In this specification, the term "adhesive resin" encompasses not only resins that are adhesive by themselves, but also resins that exhibit adhesiveness in combination with other components such as additives, and resins that exhibit adhesiveness in the presence of a trigger such as heat or water.

[0096] Examples of adhesive resins include rubber-based resins such as acrylic resins, urethane resins, and polyisobutylene resins, polyester resins, olefin resins, silicone resins, epoxy resins, and polyvinyl ether resins. The thickness of the adhesive layer is not particularly limited, but is preferably 1 to 50 μm, and more preferably 2 to 30 μm.

[0097] The adhesive layer may be formed directly on the electrode on the integrated product from a pressure-sensitive adhesive composition containing a pressure-sensitive adhesive resin by a known method, such as spin coating, spray coating, bar coating, knife coating, roll coating, roll knife coating, blade coating, die coating, or gravure coating.

[0098] At least one side of the adhesive layer may be covered with a release film until it is attached to the vapor chamber. The release film is not particularly limited. However, from the viewpoint of ease of handling, the release film preferably comprises a release substrate and a release agent layer formed by applying a release agent to the release substrate. The release film may also comprise a release agent layer on only one side of the release substrate, or on both sides of the release substrate. Examples of release substrates include paper substrates, laminated paper obtained by laminating a thermoplastic resin such as polyethylene to the paper substrate, and plastic films. Examples of paper substrates include glassine paper, coated paper, and cast-coated paper. Examples of plastic films include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, as well as polyolefin films such as polypropylene and polyethylene. Examples of release agents include olefin-based resins, rubber-based elastomers (e.g., butadiene-based resins, isoprene-based resins, etc.), long-chain alkyl resins, alkyd-based resins, fluorine-based resins, and silicone-based resins.

[0099] The adhesive layer having a release film is produced, for example, through the following steps. First, an adhesive composition is applied to a release film to form a coating film. Next, the coating film is dried to form an adhesive layer. Next, the adhesive layer on the release film and the electrode on the integrated product are bonded together to produce the adhesive layer.

[0100] <Installation of Peltier Element> The Peltier element is attached to the back surface of the vapor chamber by adhering the Peltier element to the vapor chamber with the adhesive layer.

[0101] [Another Example of a Method for Manufacturing a Temperature Control Module] When assembling a vapor chamber after forming a thermoelectric conversion element, the thermoelectric conversion element can be fabricated on the flat plate or sheet that constitutes the vapor chamber, rather than on the substrate. In this case, instead of providing the adhesive layer on the Peltier element, a passivation film is optionally formed on the flat plate or sheet that constitutes the vapor chamber, and then a lower-side connection electrode is formed directly on the surface of the flat plate or sheet that constitutes the vapor chamber or on the passivation film. A thermoelectric semiconductor material composition is then applied, and drying and annealing treatments are performed as necessary to fabricate the thermoelectric conversion element. The insulator is then filled between the thermoelectric conversion elements, and then an upper-side connection electrode is formed. An adhesive layer is then optionally formed on the upper-side connection electrode. In this case, if the adhesive layer is curable, the adhesiveness of the upper-side adhesive layer can be easily eliminated by curing the adhesive layer. Thereafter, the other flat plate or sheet is joined, the working fluid is injected, and the injection port is sealed to complete the vapor chamber, thereby obtaining a temperature control module. When Peltier elements are disposed on both sides of the vapor chamber, as in the temperature control module 1C shown in Figure 3, the Peltier elements are formed on each of the first and second sheets using the procedure described above, and then the first and second sheets are joined to assemble the vapor chamber. In this way, by forming the thermoelectric conversion elements by coating on the flat plates or sheets that make up the vapor chamber, other layers such as intervening layers are not required, making it easier to obtain a thinner temperature control module.

[0102] The temperature control module of the present invention is a thin temperature control module with high cooling performance, and is therefore suitable for applications requiring installation in a small space, particularly applications such as portable electronic devices in which components with high heat generation temperatures are placed in a small space. The temperature control module can also be suitable for applications requiring lightweight design and flexibility. This application is based on a Japanese patent application (Patent Application No. 2022-002595) filed on January 11, 2022, the entire contents of which are incorporated by reference.

[0103] DESCRIPTION OF SYMBOLS 1A, 1B, 1C, 1D, 1E: Temperature control module 10: First sheet 11: Peripheral edge portion 12: Recess 13: Convex rib 14, 15: Groove (condensate flow path) 16, 17: Liquid communication opening 18: Inlet forming portion 20: Second sheet 21: Peripheral edge portion 22: Recess 23: Convex rib 24: Inlet 30: Vapor chamber 31: Sealed space (vapor flow path) 32: Planned installation area 40, 70, 80: Peltier element 41, 71, 81: First connecting electrode 42, 72, 82: Second connecting electrode 43, 73, 83: P-type thermoelectric conversion element 44, 74, 84: N-type thermoelectric conversion element 45, 75, 85: Filler layer 46, 76, 86: Insulator layer 47, 77, 87: Covering layer 48, 78, 88: Thermoelectric conversion layer 50: Temperature control target member 60: Intermediate layer D: Thickness of temperature control module D1: Total thickness of Peltier element and vapor chamber D2: Thickness of vapor chamber D3: Thickness of Peltier element D4: Thickness of intermediate layer D31: Thickness of first Peltier element D32: Thickness of second Peltier element

Claims

1. A Peltier element and a vapor chamber stacked on the Peltier element, A temperature control module, wherein the total thickness of the Peltier element and the vapor chamber is 1 mm or less.

2. A temperature control module comprising a Peltier element and a vapor chamber stacked on the Peltier element, wherein the temperature control module has a thickness of 1 mm or less.

3. 3. The temperature control module according to claim 1, wherein the Peltier element comprises a thermoelectric conversion layer including a plurality of thermoelectric conversion elements, and the plurality of thermoelectric conversion elements are formed by firing a coating of a composition including a thermoelectric semiconductor material.

4. The temperature control module of claim 3 , wherein the composition comprising the thermoelectric semiconductor material comprises thermoelectric semiconductor particles, a polymeric component, and an ionic compound.

5. 3. The temperature control module according to claim 1, wherein the Peltier element comprises a thermoelectric conversion layer including a plurality of thermoelectric conversion elements, the plurality of thermoelectric conversion elements including a bismuth-tellurium compound.

6. 3. The temperature control module of claim 1, which is a cooling module.