Thermoelectric module

Abstract

This technology offers advantages in improving the performance of thermoelectric modules. [Solution] A thermoelectric module comprising a first substrate having a first main surface, a second substrate having a second main surface arranged facing the first main surface, a plurality of thermoelectric elements arranged between the first main surface and the second main surface, and an electrode arranged on the first main surface to which a first thermoelectric element and a second thermoelectric element among the plurality of thermoelectric elements are connected, wherein the first main surface is provided with an insulating layer comprising a first portion arranged so as to surround the electrode and spaced apart from the electrode, and a second portion arranged between the first thermoelectric element and the second thermoelectric element.

Description

Technical Field

[0001] The present invention relates to a thermoelectric module.

Background Art

[0002] Thermoelectric modules using the Seebeck effect and the Peltier effect are known. As such a thermoelectric module, the use of a so-called π-type thermoelectric conversion element is known. The π-type thermoelectric conversion element is configured by disposing a P-type thermoelectric element on one of a pair of electrodes spaced apart from each other provided on a substrate, an N-type thermoelectric element on the other electrode, and connecting the upper surfaces of both thermoelectric elements to a common electrode provided on a substrate facing each other. In the manufacture of such a thermoelectric module, the P-type thermoelectric element and the N-type thermoelectric element are respectively joined to the electrodes provided on the substrate via a joining material. When a soldering material or the like is used as the joining material, during joining by heating such as reflow, the molten solder flows due to surface tension or the like, and displacement of the thermoelectric element may occur. When the thermoelectric element is displaced, problems such as a short circuit may occur due to contact of the thermoelectric element with an adjacent electrode. Patent Document 1 shows that a wall structure is arranged so as to surround the thermoelectric element on the electrode to suppress displacement of the thermoelectric element.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order to improve the performance of the thermoelectric module, it is desirable to improve the mounting density of the thermoelectric elements arranged on the substrate.

[0005] An object of the present invention is to provide a technique advantageous for improving the performance of a thermoelectric module. [Means for solving the problem]

[0006] In view of the above problems, a thermoelectric module according to an embodiment of the present invention is a thermoelectric module comprising: a first substrate having a first main surface; a second substrate having a second main surface arranged facing the first main surface; a plurality of thermoelectric elements arranged between the first main surface and the second main surface; and an electrode arranged on the first main surface to which a first thermoelectric element and a second thermoelectric element among the plurality of thermoelectric elements are connected, wherein the first main surface is provided with an insulating layer comprising: a first portion arranged so as to surround the electrode and spaced apart from the electrode; and a second portion arranged between the first thermoelectric element and the second thermoelectric element. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a technology that is advantageous for improving the performance of thermoelectric modules. [Brief explanation of the drawing]

[0008] [Figure 1] A perspective view showing an example configuration of the thermoelectric module of this embodiment. [Figure 2] Figure 1 illustrates the improvement in the mounting density of thermoelectric modules. [Figure 3] Figure 1 shows an example of the arrangement of the insulating layer in a thermoelectric module. [Figure 4] Figure 1 shows an example of the arrangement of the insulating layer in a thermoelectric module. [Figure 5] Figure 1 shows an example of the electrode shape of a thermoelectric module. [Figure 6] Figure 1 shows an example of the arrangement of the insulating layer in a thermoelectric module. [Figure 7] This figure shows a modified version of the thermoelectric module shown in Figure 1. [Modes for carrying out the invention]

[0009] The embodiments will be described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the invention as defined in the claims, and not all combinations of features described in the embodiments are essential to the invention. Two or more of the features described in the embodiments may be combined in any way. Furthermore, identical or similar configurations will be given the same reference numeral, and redundant descriptions will be omitted.

[0010] A thermoelectric module 100 according to an embodiment of the present disclosure will be described with reference to Figures 1 to 7(a) and 7(b). Figure 1 is a diagram showing an example configuration of the thermoelectric module 100 of this embodiment. The upper part of Figure 1 shows a cross-section of the thermoelectric module 100. The lower part of Figure 1 shows a plan view focusing on an example of the arrangement of electrodes 112 and insulating layer 110 on the substrate 111 of the thermoelectric module 100. The upper cross-sectional view represents the cross-section between A and A' in the lower plan view. In addition, in the lower plan view, the thermoelectric elements 130 other than the two in the upper left are omitted in order to focus on the arrangement of electrodes 112 and insulating layer 110.

[0011] The thermoelectric module 100 includes a substrate 111 having a main surface 114, a substrate 121 having a main surface 124 facing the main surface 114 of substrate 111, and a plurality of thermoelectric elements 130 disposed between the main surface 114 of substrate 111 and the main surface 124 of substrate 121. A plurality of electrodes 112 are arranged on the main surface 114 of substrate 111. Two thermoelectric elements 130 are connected to one electrode 112 via a bonding material 113 made of solder or the like. The thermoelectric elements 130 connected to one electrode 112 may be N-type thermoelectric elements 130n and P-type thermoelectric elements 130p, which have different conductivity types, as shown in Figure 1. Similarly, a plurality of electrodes 122 are arranged on the main surface 124 of substrate 121. Two thermoelectric elements 130 are connected to one electrode 122 via a bonding material 123 made of solder or the like. The thermoelectric elements 130 connected to one electrode 112 may be N-type thermoelectric elements 130n and P-type thermoelectric elements 130p, which have different conductivity types, as shown in Figure 1. The thermoelectric module 100 shown in Figure 1 has the structure of a so-called π-type thermoelectric conversion element, in which N-type thermoelectric elements 130n and P-type thermoelectric elements 130p are connected alternately in series.

[0012] When manufacturing the thermoelectric module 100, the thermoelectric element 130 is joined to the electrode 112 via a bonding material 123 made of solder material or the like. When the thermoelectric element 130 and the electrode 112 are joined by heating such as reflow soldering, the molten solder may flow due to surface tension, which may cause the thermoelectric element 130 to shift position. If the thermoelectric element 130 comes into contact with an electrode 112 different from the electrode 112 that it is designed to be joined to due to the shift in position of the thermoelectric element 130, it may cause a short circuit and a decrease in the characteristics of the thermoelectric module 100. Therefore, in this embodiment, the thermoelectric module 100 has an insulating layer 110 on the main surface 114 of the substrate 111, which includes a portion 110a that surrounds each electrode 112 and is spaced apart from the electrodes 112, and a portion 110b that is placed between two thermoelectric elements 130 connected to one electrode 112. The presence of the insulating layer 110 suppresses displacement of the thermoelectric element 130 caused by factors such as the flow of molten solder during reflow soldering.

[0013] Next, the advantages of having the portion 110a of the insulating layer 110 that surrounds each electrode 112 spaced apart from the electrodes 112 will be explained using Figures 2(a) and 2(b). Figure 2(a) shows the arrangement of the electrodes 112 and the insulating layer 110 in the thermoelectric module 100 of this embodiment. Figure 2(b) shows the arrangement of the electrodes 112 and the insulating layer 110 in a comparative example thermoelectric module. In the comparative example thermoelectric module, the insulating layer 110 is placed on top of the electrodes 112. In Figure 2(b), the entire insulating layer 110 is shown to be placed on top of the electrodes 112, but the insulating layer 110 may also be placed between the electrodes 112.

[0014] In the configurations shown in Figures 2(a) and 2(b), thermoelectric elements 130 of the same size are arranged (shown in the upper left of each figure). That is, the size of the opening for arranging the thermoelectric elements 130 provided in the insulating layer 110 is the same. Also, the minimum formation width when forming the insulating layer 110 is defined as length D1. Furthermore, in the comparative example thermoelectric module, the minimum distance between electrodes 112 required for processing when forming the electrodes 112 is defined as length D2. Also, in the comparative example thermoelectric module, considering the formation accuracy and positional deviation of the insulating layer 110 when forming the insulating layer 110 on the electrodes 112, the formation width of the insulating layer 110 on the electrodes 112 is defined as length D3.

[0015] As shown in Fig. 2(a), in the thermoelectric module 100 according to the present embodiment, the thermoelectric elements 130 will be arranged at intervals of a length D1 in the vertical and horizontal directions. On the other hand, in the thermoelectric module of the comparative example shown in Fig. 2(b), the interval between the thermoelectric elements 130 connected to the adjacent electrodes 112 is a length Dt = D2 + D3×2 both in the vertical and horizontal directions. The length D3, which is the formation width on the electrode 112, can be set to be equal to or greater than the length D1 (D1≤D3) due to formation accuracy, misalignment, etc. when forming the insulating layer 110 on the electrode 112. Therefore, the relationship between the length D1, which is the interval at which the thermoelectric elements 130 are arranged in the thermoelectric module 100 of the present embodiment, and the length Dt, which is the interval at which the thermoelectric elements 130 are arranged in the thermoelectric module of the comparative example, is Dt = D2 + D3×2 > D1. As is clear from Figs. 2(a) and 2(b), the thermoelectric module 100 of the present embodiment has a smaller area for arranging the same number of thermoelectric elements 130 than the thermoelectric module of the comparative example. In other words, by separating the portion 110a of the insulating layer 110 arranged so as to surround the electrode 112 from the electrode 112, the mounting density of the thermoelectric elements ********* 130 arranged on the substrate 111 can be improved. That is, by suppressing the misalignment of the thermoelectric elements 130 during manufacturing, etc., it is possible to suppress the occurrence of defects while increasing the number of thermoelectric elements 130 per unit area, and it can be said that the thermoelectric module 100 of the present embodiment has a structure suitable for performance improvement.

[0016] Next, the structure of the insulating layer 110 will be described. In the configuration shown in Fig. 1, the insulating layer 110 is formed so as to continuously surround each of the thermoelectric elements 130. Thereby, the misalignment of the thermoelectric elements 130 can be suppressed. As shown in Fig. 1, the upper surface of the insulating layer 110 may be arranged at a position closer to the main surface 124 of the substrate 121 than the surface facing the electrode 112 arranged on the substrate 111 of the thermoelectric element 130. Further, for example, the upper surface of the insulating layer 110 may be arranged at the same height as the surface facing the electrode 112 arranged on the substrate 111 of the thermoelectric element 130.

[0017] It should be noted that there seems to be some text missing in the part marked with "*********" in the translation of . Please check and correct the original text if necessary.By positioning the upper surface of the insulating layer 110 closer to the substrate 121 than the surface of the thermoelectric element 130 facing the electrode 112, movement of the thermoelectric element 130 is suppressed even if the solder used as a bonding material 113 melts and flows during reflow soldering. For example, the upper surface of the insulating layer 110 may be positioned 2 μm or more closer to the main surface 124 of the substrate 121 than the surface of the thermoelectric element 130 facing the electrode 112. Alternatively, for example, the upper surface of the insulating layer 110 may be positioned 3 μm or more closer to the main surface 124 of the substrate 121 than the surface of the thermoelectric element 130 facing the electrode 112. Furthermore, for example, the upper surface of the insulating layer 110 may be positioned 4 μm or more closer to the main surface 124 of the substrate 121 than the surface of the thermoelectric element 130 facing the electrode 112. Furthermore, even if the upper surface of the insulating layer 110 is at approximately the same height as the surface of the thermoelectric element 130 facing the electrode 112, the flow of molten solder is suppressed, and as a result, displacement of the thermoelectric element 130 is suppressed. On the other hand, if the height of the insulating layer 110 is increased, it may interfere with the substrate 121 or the electrode 122 arranged on the substrate 121. For this reason, the upper surface of the insulating layer 110 is positioned at the same height as the surface of the thermoelectric element 130 facing the electrode 122 arranged on the substrate 121, or closer to the main surface 114 of the substrate 111 than the surface of the thermoelectric element 130 facing the electrode 122 arranged on the substrate 121. The upper surface of the insulating layer 110 may be positioned, for example, 2 μm or more closer to the main surface 114 of the substrate 111 than the surface of the thermoelectric element 130 facing the electrode 122, or 10 μm or more, or even 50 μm or more closer to the main surface 114 of the substrate 111. For example, the upper surface of the insulating layer 110 may be positioned from the same height as the surface of the thermoelectric element 130 facing the electrode 112 to the portion of the thermoelectric element 130 that is half the height between the substrate 111 and the substrate 121, or to the portion that is one-third the height, or to the portion that is one-fifth the height. Also, for example, the upper surface of the insulating layer 110 may be positioned at a height of 1 to 100 times the thickness of the bonding material 113 from the surface of the electrode 112, or at a height of 2 to 20 times the thickness of the bonding material 113, or even at a height of 3 to 7 times the thickness of the bonding material 113.Here, the upper and lower limits such as "1 to 100 times," "2 to 20 times," and "3 to 7 times" are not limited to the combinations listed, but can be combined with each other. For example, "1 to 100 times" means "1 times or more, and 100 times or less." The same applies to the upper and lower limits of numerical ranges in the following descriptions.

[0018] In the configuration shown in Figure 1, the insulating layer 110 is formed to continuously surround each of the thermoelectric elements 130, but it is not limited to this. The insulating layer 110 may be formed to intermittently surround each of the thermoelectric elements 130. For example, as shown in Figure 3(a), the portion 110b of the insulating layer 110 that is positioned between two thermoelectric elements 130 connected to the same electrode 112 may be divided into two portions that protrude from the portion 110a of the insulating layer 110 that surrounds the electrode 112. In that case, as shown in Figure 3(a), the portion 110b of the insulating layer 110 does not have to be positioned on the electrode 112. Also, as shown in Figure 3(b), the portion 110b of the insulating layer 110 may be positioned at a distance from the portion 110a of the insulating layer 110. In the configuration shown in Figure 3(b), portion 110b of the insulating layer 110 is formed to traverse the electrode 112, but it may also be formed on a portion of the electrode 112, for example, as shown in Figure 3(c). Alternatively, as shown in Figure 3(d), portion 110b of the insulating layer 110 may be spaced apart from portion 110a of the insulating layer 110 and may consist of two or more portions.

[0019] Also, the portion 110a of the insulating layer 110 that surrounds the electrode 112 does not have to continuously surround the electrode 112 and may intermittently surround the electrode 112. For example, as shown in FIG. 4(a), the insulating layer 110 may be arranged to suppress misalignment at each corner of the thermoelectric element 130. Also, for example, as shown in FIG. 4(b), the insulating layer 110 may be arranged to suppress misalignment at each side of the thermoelectric element 130. In the configuration shown in FIG. 4(b), the portion of the insulating layer 110 corresponding to each side of the thermoelectric element 130 is formed of one element, but it may be divided into two or more. Also, for example, the configuration shown in FIG. 4(a) and the configuration shown in FIG. 4(b) may be combined.

[0020] In the configurations shown in FIGS. 3(a) to 3(d), 4(a), and 4(b), in the orthographic projection onto the main surface 114 of the substrate 111, the portion of the insulating layer 110 arranged to surround one thermoelectric element 130 intermittently surrounds one thermoelectric element in a rectangular shape. In that case, as shown in FIGS. 3(a) to 3(d), 4(a), and 4(b), the insulating layer 110 may be arranged to form a part of each of the four sides of the rectangle. Thereby, it becomes possible to effectively suppress the misalignment of the thermoelectric element 130. However, it is not limited thereto, and it is sufficient that the insulating layer 110 is arranged to form a part of some of the four sides of the rectangle. Even if it is a part, by arranging the insulating layer 110, the misalignment of the thermoelectric element 130 can be suppressed more than when the insulating layer 110 is not arranged.

[0021] As shown in the lower part of Figure 1, in the orthogonal projection onto the main surface 124 of the substrate 111, the shape of the inner edge of the portion of the insulating layer 110 that surrounds one thermoelectric element 130 may be substantially the same as the outer edge of the thermoelectric element 130. Furthermore, considering manufacturing variations of the insulating layer 110 and the thermoelectric element 130, the shape of the inner edge of the portion of the insulating layer 110 that surrounds one thermoelectric element 130 may be larger than the outer edge of the thermoelectric element 130. However, if the inner edge of the portion of the insulating layer 110 that surrounds one thermoelectric element 130 becomes larger, the mounting density of the thermoelectric element 130 will decrease. Therefore, although it also depends on the size of the thermoelectric element 130, the length between the inner edge of the insulating layer 110 and the outer edge of the thermoelectric element 130 may be, for example, 200 μm or less, or for example, 100 μm or less, or for example, 50 μm or less, or for example, 20 μm or less. Furthermore, for example, if the thermoelectric element 130 is approximately square in the orthogonal projection onto the main surface 124 of the substrate 111, the length between the inner edge of the insulating layer 110 and the outer edge of the thermoelectric element 130 may be 20% or less of one side of the square of the thermoelectric element 130. In that case, the length between the inner edge of the insulating layer 110 and the outer edge of the thermoelectric element 130 may be, for example, 10% or less of one side of the square of the thermoelectric element 130, or for example, 5% or less, or even for example, 2% or less. Furthermore, for example, in the orthogonal projection onto the main surface 124 of the substrate 111, the thermoelectric element 130 is A[mm 2 Assume that it has the size of ]. In that case, the length between the inner edge of the insulating layer 110 and the outer edge of the thermoelectric element 130 may be 0.2 × √A [mm] or less, 0.1 × √A [mm] or less, 0.05 × √A [mm] or less, or 0.02 × √A [mm] or less.

[0022] In the configurations shown in Figures 1, 3(a) to 3(d), 4(a), and 4(b), the electrode 112 is depicted as rectangular, but the shape of the electrode 112 is not limited to a rectangular shape. Figures 5(a) to 5(e) show examples of the shape of the electrode 112. The electrode 112 may have a shape with rounded corners, as shown in Figure 5(a), or it may have an arc shape at its end, as shown in Figure 5(b). In the configuration shown in Figure 5(a), all four corners are rounded, but only some corners may be rounded. Also, for example, the corners of the electrode 112 may be chamfered in a straight line. Furthermore, the width of the portion of the electrode 112 that is positioned between the two portions to which the thermoelectric element 130 is joined may be narrower than the portion to which the thermoelectric element 130 is joined. For example, as shown in Figure 5(c), the portion to which the thermoelectric element 130 is joined may be rectangular in shape, and the width between them may be narrower than the length of one side of the rectangle. Alternatively, as shown in Figure 5(d), the four corners (or some of the corners) of the rectangular portion to which the thermoelectric element 130 is joined may be chamfered. Furthermore, as shown in Figure 5(e), for example, the portion to which the thermoelectric element 130 is joined may be circular in shape, and the electrode 112 may have a configuration in which two circular portions are connected by a portion narrower than the diameter of the circle. The shape of the electrode 112 should be selected appropriately depending on the shape of the thermoelectric element 130 and the bonding strength between the electrode 112 and the thermoelectric element 130.

[0023] While an appropriate shape is selected for the electrode 112, the length between the portion 110a surrounding the electrode 112 in the insulating layer 110 in the orthogonal projection onto the main surface 124 of the substrate 111 and the outer edge of the electrode 112 may be considered as follows. Increasing the length between the portion 110a of the insulating layer 110 and the electrode 112 reduces the relative size of the electrode 112, increasing the resistance value of the electrode 112. As a result, the proportion of power consumed by the electrode 112 increases, potentially degrading the performance of the thermoelectric module 100. Furthermore, the bonding strength between the electrode 112 and the thermoelectric element 130 may decrease. On the other hand, reducing the length between the portion 110a of the insulating layer 110 and the electrode 112 increases the relative size of the electrode 112, thus suppressing the problems of power consumption and bonding strength in the electrode 112. However, solder used as a bonding material 113 during reflow soldering may leak beyond the area where the insulating layer 110 is not present, potentially causing a short circuit between adjacent electrodes. Furthermore, if the length between portion 110a of the insulating layer 110 and the electrode 112 is reduced, high alignment accuracy is required in the process of forming the insulating layer 110. This could potentially lead to a decrease in manufacturing efficiency, for example, by increasing the time required for alignment.

[0024] Therefore, for example, if the thermoelectric element 130 is approximately square in the orthogonal projection onto the main surface 124 of the substrate 111, the length between the portion of the insulating layer 110a closest to the electrode 112 and the electrode 112 may be 5 to 30% of one side of the square of the thermoelectric element 130. In that case, the length between the portion of the insulating layer 110a closest to the electrode 112 and the electrode 112 may be, for example, 7% or more of one side of the square of the thermoelectric element 130, or 10% or more, or even 15% or more. On the other hand, the length between the portion of the insulating layer 110a closest to the electrode 112 and the electrode 112 may be, for example, 25% or less of one side of the square of the thermoelectric element 130, or 20% or less, or even 18% or less. Furthermore, for example, in the orthogonal projection onto the main surface 124 of the substrate 111, the thermoelectric element 130 is A[mm 2 Let's assume it has the size of ]. In that case, the length between the part of the insulating layer 110a closest to the electrode 112 and the electrode 112 may be 0.05 × √A ~ 0.3 × √A [mm], or for example, 0.07 × √A ~ 0.25 × √A [mm], or for example, 0.1 × √A ~ 0.2 × √A [mm], or for example, 0.15 × √A ~ 0.18 × √A [mm]. Also, depending on the size of the thermoelectric element 130, the length between the part of the insulating layer 110a closest to the electrode 112 and the electrode 112 may be, for example, 50 μm or more, or for example, 75 μm or more, or for example, 100 μm or more, or for example, 150 μm or more. On the other hand, the length between the portion of the insulating layer 110a closest to the electrode 112 and the electrode 112 may be, for example, 300 μm or less, or 250 μm or less, or even 200 μm or less, or even 180 μm or less. This makes it possible to suppress an increase in the resistance value of the electrode 112 while suppressing solder leakage and a decrease in manufacturing efficiency.

[0025] Figures 3(a) to 3(d), 4(a), and 4(b) show examples of the arrangement of the insulating layer 110 for two electrodes 112, but the insulating layer 110 can be arranged for more electrodes 112. Figure 6(a) shows an example of the arrangement of the insulating layer 110 when the insulating layer 110 continuously surrounds each of the thermoelectric elements 130, and additional electrodes 112 are arranged in the vertical and horizontal directions of the figure. Similarly, Figure 6(b) and Figure 6(c) show examples of the arrangement of the insulating layer 110 when additional electrodes 112 are arranged in the vertical and horizontal directions of the figure, compared to the configurations shown in Figure 4(a) and Figure 3(b). In other configurations as well, even when additional electrodes 112 are arranged in the vertical and horizontal directions of the figure, the insulating layer 110 can be arranged as appropriate. Furthermore, the shape of the electrodes 112 is not limited to a rectangular shape; for example, shapes such as those shown in Figures 5(a) to 5(e) can be used.

[0026] Furthermore, the insulating layer 110 is not limited to being placed only on the main surface 114 of the substrate 111. As shown in Figure 7(a), the insulating layer 120 may also be placed on the main surface 124 of the substrate 121, which is positioned opposite the main surface 114 of the substrate 111. Also, as shown in Figure 7(b), the insulating layer 110 may not be placed on the main surface 114 of the substrate 111, but the insulating layer 120 may be placed on the main surface 124 of the substrate 121. For example, in the manufacturing process of the thermoelectric module 100, it is sufficient for the insulating layer to be placed on the substrate 111 and the substrate 121 that has electrodes to which the thermoelectric element 130 is first connected. This helps to suppress misalignment of the thermoelectric element 130. For example, the insulating layer 120 disposed on the main surface 124 of the substrate 121 includes a portion that surrounds each electrode 122 and is spaced apart from the electrodes 122, and a portion that is disposed between two thermoelectric elements 130 connected to one electrode 122. The other configurations of the insulating layer 120 may be similar to the various configurations of the insulating layer 110 described above. Therefore, a description of the insulating layer 120 will be omitted.

[0027] The following describes the materials and other aspects of each component of the thermoelectric module 100.

[0028] Substrates 111 and 121 can be insulating substrates. For example, plastic films may be used for substrates 111 and 121. Examples of plastic films include polyimide films, polyamide films, polyetherimide films, polyaramid films, polyamideimide films, and glass epoxy sheets. Substrates 111 and 121 may be made of the same material, or they may be made of different materials. The thickness of substrates 111 and 121 may be 1 to 1000 μm, for example, 10 to 500 μm, or for example, 20 to 100 μm. Furthermore, the materials used for substrates 111 and 121 are not limited to plastics. For example, ceramics such as alumina or aluminum nitride may be used for substrates 111 and 121. Also, for example, conductive materials covered with an insulating layer, such as an aluminum substrate with an alumina layer formed on its surface, may be used for substrates 111 and 121.

[0029] In the thermoelectric module 100, the thermoelectric elements 130 can be arranged between substrates 111 and 121 such that an N-type thermoelectric element 130n and a P-type thermoelectric element 130p are electrically connected in series. The thermoelectric elements 130n and 130p do not necessarily have to be arranged alternately, as shown in the upper part of Figure 1, and can be arranged in an appropriate order depending on the configuration of the electrodes 112 and 122 arranged on substrates 111 and 121. The thermoelectric elements 130 can be made of various thermoelectric materials such as bismuth-tellurium, telluride, antimony-tellurium, zinc-antimony, silicon-germanium, bismuth selenide, silicide, skutterudite, oxide, and sulfide. The thickness of the thermoelectric element 130 in the direction sandwiched between the substrate 111 and the substrate 121 may be, for example, 10 to 1000 μm, more specifically, 20 to 500 μm, or more specifically, 50 to 200 μm, or even more specifically, 80 to 120 μm.

[0030] The electrodes 112 and 122 may be made of materials such as gold, silver, copper, molybdenum, nickel, aluminum, rhodium, platinum, chromium, palladium, tungsten, stainless steel, or alloys thereof. Alternatively, the electrodes 112 and 122 may be formed using a paste material containing a solvent or resin component in addition to the metal material. When using a paste material, the solvent or resin component may be removed by firing or other processes. Examples of paste materials include silver paste and aluminum paste.

[0031] Methods for forming electrodes 112 and 122 include methods for processing into a predetermined pattern shape by known physical or chemical treatments, mainly photolithography, or by using a combination of these methods, or by forming the electrode pattern by screen printing, stencil printing, inkjet printing, etc. Methods for forming the electrodes before pattern formation include vacuum deposition methods such as PVD (physical vapor deposition) methods such as vacuum deposition, sputtering, and ion plating, 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, as well as silver halide methods, electrolytic plating, electroless plating, and metal foil lamination, which are appropriately selected depending on the metal material. Furthermore, when ceramics such as alumina or aluminum nitride are used as substrates 111 and 121, electrodes 112 and 122 may be formed using DBC or AMB methods.

[0032] High conductivity is required for electrodes 112 and 122. Since electrodes formed by plating or vacuum deposition can easily achieve high conductivity, electrodes 112 and 122 may be formed using vacuum deposition methods such as vacuum evaporation and sputtering, as well as electrolytic plating and electroless plating. Depending on the required dimensions and dimensional accuracy of the electrodes 112 and 122, electrodes 112 and 122 can also be easily formed using a hard mask such as a metal mask. Furthermore, when forming a film using vacuum deposition, the substrates 111 and 121 may be heated during deposition to improve adhesion to the substrates 111 and 121 and to remove moisture, to the extent that the properties of the substrates 111 and 121 are not impaired. When forming a film using plating, further film formation may be performed on a film formed using electroless plating using electrolytic plating.

[0033] The thickness of electrodes 112 and 122 may be, for example, 0.01 to 200 μm, 1 to 100 μm, or even 10 to 50 μm. The thickness of electrodes 112 and 122 can be set appropriately according to the required resistance value of electrodes 112 and 122.

[0034] For joining the thermoelectric element 130 onto electrodes 112 and 122, a soldering material such as solder paste can be used as a bonding material 113 and 123. Solder paste can be applied to electrodes 112 and 122 with high precision and in a short time by screen printing using a stencil plate, for example. Known materials that can be used as soldering materials include Sn, Sn / Pb alloy, Sn / Ag alloy, Sn / Cu alloy, Sn / Ag / Cu alloy, Sn / Sb alloy, Sn / In alloy, Sn / Zn alloy, Sn / In / Bi alloy, Sn / In / Bi / Zn alloy, Sn / Bi / Pb / Cd alloy, Sn / Bi / Pb alloy, Sn / Bi / Cd alloy, Bi / Pb alloy, Sn / Bi / Zn alloy, Sn / Bi alloy, Sn / Bi / Pb alloy, Sn / Pb / Cd alloy, and Sn / Cd alloy. The thickness of the bonding material 113, 123 after the reflow process of bonding the thermoelectric element 130 to the electrodes 112, 122 may be, for example, 2 to 20 μm, or for example, 5 to 15 μm, or even for example, 7 to 12 μm. The thickness that allows for the stable formation of numerous bonding points between the electrodes 112, 122 and the thermoelectric element 130 can be appropriately selected.

[0035] Although not shown in Figures 1, 7(a), 7(b), etc., a solder receiving layer may be placed between the bonding materials 113, 123 and the thermoelectric element 130. The solder receiving layer has the function of improving the bonding between the thermoelectric element 130 and the bonding materials 113, 123 and is directly bonded to the thermoelectric element 130. The solder receiving layer may contain a metallic material. The metallic material may be at least one selected from gold, silver, nickel, aluminum, rhodium, platinum, chromium, palladium, tin, and alloys containing any of these metallic materials. Among these, a two-layer structure of gold, silver, nickel, aluminum, or tin and gold is also possible. From the viewpoint of material cost, high thermal conductivity, and bonding stability, silver, nickel, and aluminum are more suitable as solder receiving layers.

[0036] The thickness of the solder receiving layer may be, for example, 0.01 to 10 μm, 0.05 to 8 μm, 0.2 to 4 μm, or 0.5 to 3 μm. When the thickness of the solder receiving layer is within this range, excellent adhesion to the surface of the thermoelectric element 130 and to the bonding materials 113 and 123 can be achieved, resulting in a highly reliable bond. Furthermore, since both electrical conductivity and thermal conductivity can be maintained at a high level, the thermoelectric performance of the thermoelectric module 100 will not decrease and will be maintained. The solder receiving layer may be formed by depositing a metal material as is and used as a single layer, or it may be formed by laminating two or more metal materials and used as a multilayer.

[0037] The solder receiving layer can be formed using the aforementioned metal materials. The solder receiving layer requires high electrical conductivity and high thermal conductivity to maintain thermoelectric performance. Therefore, the solder receiving layer can be formed using the electrolytic plating method, electroless plating method, or vacuum deposition method described above.

[0038] The materials of the insulating layers 110 and 120 are not particularly limited, but from the viewpoint of suppressing the wetting spread of the solder material used as the bonding material 113 and 123, solder resist may be used. Examples of solder resists include acrylic resin, epoxy resin, urethane resin, and polyimide resin. Among these, epoxy resin and polyimide resin may be used as the material for the insulating layer 110 from the viewpoint of heat resistance.

[0039] Methods for forming the insulating layers 110 and 120 include known physical and chemical treatments, mainly photolithography, or methods that combine these to process the layers into a predetermined pattern shape. Methods for forming the insulating layer 110 include screen printing, stencil printing, inkjet printing, and other methods that directly form the pattern of the insulating layer 110. Here, from the viewpoint of insulating properties, the insulating layers 110 and 120 are, for example, 1.0 × 10⁻⁶. 11 Ω / m 2The layers may have surface resistivity as described above. Furthermore, for example, the insulating layers 110 and 120 may have a contact angle with water of 60° or more, from the viewpoint of suppressing the wetting spread of solder material and the like. In addition, the insulating layers 110 and 120 may be layers with a contact angle with water of 60 to 90°. For example, the insulating layers 110 and 120 may have a contact angle with water of 70 to 80°.

[0040] The heights of the insulating layers 110 and 120 can be appropriately adjusted within the range of the above-described configuration, depending on the thickness of the thermoelectric element 130, the thickness of the bonding material 113 and 123 (for example, the solder material (and solder receiving layer)), the thickness of the electrodes 112 and 122, and the length between the main surface 114 of the substrate 111 and the main surface 124 of the substrate 121. Furthermore, the thickness of the insulating layers 110 and 120 may differ between the portion placed on the main surfaces 114 and 124 of the substrates 111 and 121 and the portion placed on the electrodes 112 and 122, or they may be the same. For example, if solder resist is uniformly applied to the main surfaces 114 and 124 of substrates 111 and 121 as the material for insulating layers 110 and 120, and an opening is made for the portion where the thermoelectric element 130 is placed using a lithography method, the thickness of the portion of the insulating layer 110 and 120 that is placed on the main surfaces 114 and 124 of substrates 111 and 121 and the thickness of the portion that is placed on electrodes 112 and 122 may be different. On the other hand, in that case, the height of the portion of the insulating layer 110 and 120 that is placed on the main surfaces 114 and 124 of substrates 111 and 121 and the portion that is placed on electrodes 112 and 122 may be the same from the main surfaces 114 and 124 of substrates 111 and 121. Furthermore, if the pattern of the insulating layer 110 is directly formed using a screen printing method or the like, the thickness of the portion of the insulating layer 110 and 120 that is placed on the main surfaces 114 and 124 of the substrates 111 and 121 and the thickness of the portion that is placed on the electrodes 112 and 122 can be equivalent.

[0041] As described above, the thermoelectric module 100 of this embodiment includes insulating layers 110 (insulating layer 120) formed to surround each thermoelectric element 130. This suppresses misalignment of the thermoelectric elements 130, thereby suppressing problems such as short circuits, and potentially improving the manufacturing yield of the thermoelectric module 100. Furthermore, the portion 110a of the insulating layer 110 (insulating layer 120) surrounding the electrode 112 (electrode 122) is spaced apart from the electrode 112 (electrode 122). This makes it possible to improve the mounting density of the thermoelectric elements 130. In other words, the thermoelectric module 100 of this embodiment has a configuration suitable for improving the performance of the thermoelectric module.

[0042] The invention is not limited to the embodiments described above, and various modifications and changes are possible within the scope of the gist of the invention. [Explanation of Symbols]

[0043] 100: Thermoelectric module, 110,120: Insulating layer, 110a,110b: Part, 111,121: Substrate, 112,122: Electrode, 114,124: Main surface, 130: Thermoelectric element

Claims

1. A thermoelectric module comprising: a first substrate having a first main surface; a second substrate having a second main surface arranged facing the first main surface; a plurality of thermoelectric elements arranged between the first main surface and the second main surface; and an electrode arranged on the first main surface to which a first thermoelectric element and a second thermoelectric element among the plurality of thermoelectric elements are connected, A thermoelectric module characterized in that an insulating layer is provided on the first main surface, the insulating layer comprising a first portion arranged so as to surround the electrode and spaced apart from the electrode, and a second portion arranged between the first thermoelectric element and the second thermoelectric element.

2. The thermoelectric module according to claim 1, characterized in that the insulating layer is formed to continuously or intermittently surround the first thermoelectric element and the second thermoelectric element, respectively.

3. The thermoelectric module according to claim 2, characterized in that, in the orthogonal projection onto the first main surface, the portion of the insulating layer arranged to surround the first thermoelectric element intermittently surrounds the first thermoelectric element in a rectangular shape and is arranged to constitute a part of each of the four sides of the rectangular shape.

4. The thermoelectric module according to claim 2, characterized in that, in the orthogonal projection onto the first main surface, the shape of the inner edge of the portion of the insulating layer arranged to surround the first thermoelectric element is the same shape as or larger than the outer edge of the first thermoelectric element.

5. In the orthogonal projection onto the first principal surface, each of the plurality of thermoelectric elements is A [mm] ２ It has the size of ] The thermoelectric module according to claim 1, characterized in that the length between the portion of the first part closest to the electrode and the electrode is 0.05 × √A [mm] or more and 0.3 × √A [mm] or less.

6. The thermoelectric module according to claim 1, characterized in that the upper surface of the insulating layer is positioned at the same height as the surfaces of the first thermoelectric element and the second thermoelectric element facing the electrodes, or is positioned closer to the second main surface than the surfaces facing each other.

7. The thermoelectric module according to claim 1, characterized in that the upper surface of the insulating layer is positioned at a location 2 μm or more closer to the second main surface than the surfaces of the first thermoelectric element and the second thermoelectric element facing the electrodes.

8. The thermoelectric module according to claim 1, characterized in that the first thermoelectric element and the second thermoelectric element have different conductivity types.

9. The electrode is referred to as the first electrode, and the insulating layer as the first insulating layer. The thermoelectric module further includes a second electrode arranged on the second main surface, to which the first thermoelectric element and a third thermoelectric element among the plurality of thermoelectric elements are connected. The thermoelectric module according to claim 1, characterized in that a second insulating layer is provided on the second main surface, the second insulating layer comprising a third portion arranged so as to surround the second electrode and spaced apart from the second electrode, and a fourth portion arranged between the first thermoelectric element and the third thermoelectric element.

10. The thermoelectric module according to claim 1, characterized in that the second part is not disposed on the electrodes.

11. The thermoelectric module according to claim 1, characterized in that the second part is arranged at a distance from the first part.

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