Cooling structure

Abstract

To provide a resin-made cooling structure which is excellent in cooling efficiency.SOLUTION: A cooling structure 10 has a resin-made flow channel formation member 14 forming a flow channel circulating a refrigerant, a bus bar 26 having a terminal part 28A, a terminal part 28B and a connection part 30 for connecting the terminal part 28A and the terminal part 28B, and a fastening part which is provided on an outer wall surface of the flow channel formation member 14 and fixes the terminal part 28A and the terminal part 28B of the bus bar 26 to the flow channel formation member 14, wherein at least a part of the connection part 30 is brought into contact with the refrigerant through the flow channel formation member 14.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a cooling structure. [Background technology]

[0002] Hybrid vehicles, electric vehicles, and other vehicles equipped with motors are equipped with a drive means for driving the motor. The drive means is composed of a power module equipped with multiple power semiconductors such as IGBTs (Insulated Gate Bipolar Transistors), electronic components such as capacitors, and bus bars that electrically connect these electronic components. When driving a motor, a large current may flow through the busbars that connect electronic components such as power semiconductors and capacitors. When a large current flows through the busbars, the driving means generates heat due to switching loss, resistance loss, etc., so the driving means needs to be cooled efficiently.

[0003] As a cooling means for cooling the driving means, a heat sink made of metal such as aluminum or copper is used because of its high thermal conductivity (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-182831 Summary of the Invention [Problem to be solved by the invention]

[0005] However, manufacturing a metal heat sink requires complex manufacturing processes such as extrusion, skiving, and crimping, which tends to increase the cost of the metal heat sink. Furthermore, incorporating a metal heat sink into a cooling target such as a drive unit can require a large number of steps, so there is a demand for a cooling method that provides excellent cooling efficiency without using a metal heat sink.

[0006] One aspect of the present disclosure has been made in consideration of the above-described conventional circumstances, and has an object to provide a resin cooling structure that has excellent cooling efficiency. [Means for solving the problem]

[0007] Specific means for achieving the above object are as follows. <1> a flow path forming member made of resin that forms a flow path through which a refrigerant flows; a bus bar having a plurality of terminal portions and a connecting portion connecting the plurality of terminal portions; a fastening portion provided on an outer wall surface of the flow path forming member and configured to fix the plurality of terminal portions of the bus bar to the flow path forming member, A cooling structure in which at least a portion of the connecting portion is in contact with the refrigerant via the flow path forming member. <2> the flow path forming member has an insertion groove recessed from an outer wall surface side of the flow path forming member toward the flow path, At least a part of the connecting portion is inserted into the insertion groove. <1> The cooling structure according to claim 1. <3> A wall surface on one side of the insertion groove has a protrusion that presses at least a part of the connecting portion inserted into the insertion groove against the other wall surface of the insertion groove. <2> The cooling structure according to claim 1. <4> At least a portion of the connecting portion is in contact with the outer wall of the flow path forming member. <1> The cooling structure according to claim 1. <5> A portion of the outer wall of the flow path forming member that contacts the connecting portion has a curved recess, and at least a portion of the connecting portion contacts the outer wall of the flow path forming member along the curved recess. <4> The cooling structure according to claim 1. <6> The radius of curvature of the curved recess in the outer wall of the flow path forming member is larger than the radius of curvature of the portion of the connecting portion that contacts the curved recess. <5> The cooling structure according to claim 1. <7> A portion of the outer wall of the flow path forming member that contacts the connecting portion is flat, and at least a portion of the connecting portion contacts the flat portion of the outer wall while forming a flat surface. <4> The cooling structure according to claim 1. <8> The outer wall of the flow path forming member has a buffer region in a direction in which the flat region of the connecting portion expands when the bus bar thermally expands. <7> The cooling structure according to claim 1. <9> a flow path forming member made of resin that forms a flow path through which a refrigerant flows; a bus bar having a plurality of terminal portions and a connecting portion connecting the plurality of terminal portions; a fastening portion provided on an outer wall surface of the flow path forming member and configured to fix the plurality of terminal portions of the bus bar to the flow path forming member, A cooling structure having a structure in which, when the bus bar thermally expands, the area of ​​the connecting portion that comes into contact with the refrigerant via the flow path forming member increases. [Effects of the Invention]

[0008] According to one embodiment of the present disclosure, it is possible to provide a resin cooling structure having excellent cooling efficiency. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a plan view of a main part of the cooling structure 10. [Figure 2] 2 is a cross-sectional view of the cooling structure 10 taken along line AA in FIG. 1. FIG. [Figure 3] 2 is a diagram showing an end face of the cooling structure 10 taken along line BB in FIG. 1. FIG. [Figure 4] 10 is a diagram illustrating a state in which a bus bar 26 in the cooling structure 10 has heated up and expanded. FIG. [Figure 5] 10 is a plan view showing a main part of a modified example of the cooling structure 10. FIG. [Figure 6] 10 is a diagram showing an end face of a flow path 12 of a modified example of the cooling structure 10. FIG. [Figure 7] FIG. 2 is a plan view of a main part of the cooling structure 44. [Figure 8]8 is a cross-sectional view of the cooling structure 44 taken along line CC in FIG. 7. FIG. [Figure 9] 10 is a diagram illustrating a state in which a bus bar 26 in a cooling structure 44 is heated and expanded. FIG. [Figure 10] 10 is a cross-sectional view showing a main part of a modified example of the cooling structure 44. FIG. [Figure 11] 2 is a cross-sectional view showing a main part of a cooling structure 50. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments for carrying out the present disclosure will be described in detail. However, the present disclosure is not limited to the following embodiments. In the following embodiments, components (including element steps, etc.) are not essential unless otherwise specified.

[0011] <Cooling structure> A first cooling structure of the present disclosure includes a flow path forming member made of resin that forms a flow path through which a refrigerant circulates, a bus bar having a plurality of terminal portions and connecting portions that connect the plurality of terminal portions, and fastening portions that are provided on an outer wall surface of the flow path forming member and that fix the plurality of terminal portions of the bus bar to the flow path forming member, and at least a portion of the connecting portions comes into contact with the refrigerant via the flow path forming member. In the first cooling structure of the present disclosure, at least a portion of the connecting portion constituting the bus bar comes into contact with the refrigerant via the flow path forming member, so that the bus bar that has generated heat due to the passage of current or the like can be efficiently cooled, thereby improving cooling efficiency. A second cooling structure of the present disclosure includes a flow path forming member made of resin that forms a flow path through which a refrigerant circulates, a bus bar having a plurality of terminal portions and connecting portions that connect the plurality of terminal portions, and fastening portions that are provided on an outer wall surface of the flow path forming member and fix the plurality of terminal portions of the bus bar to the flow path forming member, and has a structure in which, when the bus bar thermally expands, the area of ​​the connecting portions that come into contact with the refrigerant via the flow path forming member increases. The second cooling structure of the present disclosure has a structure in which, when the bus bar thermally expands due to the passage of current or the like, the area of ​​contact with the refrigerant increases via the flow path forming member of the connecting portion that constitutes the bus bar. This makes it possible to efficiently cool the bus bar that has generated heat due to the passage of current, thereby improving cooling efficiency. Hereinafter, the first cooling structure and the second cooling structure of the present disclosure may be collectively referred to as the cooling structure of the present disclosure.

[0012] In the first cooling structure of the present disclosure, the phrase "at least a part of the connecting portion is in contact with the refrigerant" means that at least a part of the connecting portion is in contact with the refrigerant via the flow path forming member when the bus bar is generating heat due to electrical current or the like. When the bus bar is not generating heat, the connecting portion may or may not be in contact with the refrigerant via the flow path forming member. In the cooling structure of the present disclosure, the phrase "the connecting portion comes into contact with the refrigerant "through" the flow path forming member means that the flow path forming member is interposed between the connecting portion and the refrigerant. The connecting portion does not come into direct contact with the refrigerant.

[0013] The cooling structure of the present disclosure will be described below with reference to the drawings. Note that the sizes of the components in each drawing are conceptual, and the relative size relationships between the components are not limited to these. Furthermore, components having substantially the same function are given the same reference numerals throughout the drawings, and duplicated descriptions may be omitted.

[0014] (First embodiment) 1 to 3 are diagrams showing the main parts of the cooling structure 10 according to the first embodiment, in which FIG. 1 shows a plan view of the main parts of the cooling structure 10, FIG. 2 shows a cross section of the cooling structure 10 along line AA in FIG. 1, and FIG. 3 shows an end face of the cooling structure 10 along line BB in FIG. 1. The cooling structure 10 includes a resin flow path forming member 14 that forms a flow path 12 having a substantially rectangular cross section for circulating a refrigerant. The flow path 12 is surrounded by an upper inner wall 16 that corresponds to one of a pair of opposing inner walls, a lower inner wall 18 that corresponds to the other of the opposing inner walls, and side inner walls 20 and 22 that connect the upper inner wall 16 and the lower inner wall 18.

[0015] An insertion groove 24 is provided on the outer wall surface of the flow path forming member 14, recessed from the outer wall surface side of the flow path forming member 14 toward the inside of the flow path 12. The longitudinal direction of the insertion groove 24 is aligned with the direction in which the refrigerant flows in the flow path 12.

[0016] Bus bar 26 has terminal portion 28A, terminal portion 28B, and connecting portion 30 that connects terminal portion 28A and terminal portion 28B. Connecting portion 30 is inserted into insertion groove 24 and disposed within flow path 12, and is capable of coming into contact with the refrigerant flowing through flow path 12 via the wall surface of insertion groove 24 that constitutes flow path forming member 14. A clearance is provided between the connecting portion 30 and the wall surface of the insertion groove 24 from the viewpoint of work efficiency when inserting the connecting portion 30 into the insertion groove 24 . In addition, in the cooling structure 10, a clearance is provided around the entire circumference of the connecting portion 30, and the connecting portion 30 is designed not to come into contact with the wall surface of the insertion groove 24, but the connecting portion 30 may also come into contact with at least a portion of the wall surface of the insertion groove 24.

[0017] A portion of the nut 34A opposite to the side where the bolt 32A is inserted and a portion of the nut 34B opposite to the side where the bolt 32B is inserted are provided on the outer wall surface of the flow path forming member 14.

[0018] The terminal portion 28A is fastened and fixed to the outer wall surface of the flow path forming member 14 together with the terminal portion 28C of the other bus bar 38 by a fastening portion 36A formed by a bolt 32A and a nut 34A. Terminal portion 28B is fastened and fixed to the outer wall surface of flow path forming member 14 together with terminal portions 28D of other bus bars 40 by fastening portions 36B formed of bolts 32B and nuts 34B. The bus bars 38 and 40 are connected to electronic components (not shown) such as power semiconductors and capacitors.

[0019] When a current flows through the bus bar 26, the bus bar 26 generates heat and expands. Because the terminal portions 28A and 28B of the bus bar 26 are fastened to the flow path forming member 14 by the fastening portions 36A and 36B, respectively, the distance between the terminal portions 28A and 28B does not change significantly when the bus bar 26 generates heat and expands. On the other hand, when the bus bar 26 generates heat and expands, as shown in FIG. 4 , the connecting portion 30 warps, and the connecting portion 30 is strongly pressed against one wall surface of the insertion groove 24. As a result, the area of ​​the connecting portion 30 that comes into contact with the refrigerant via the flow path forming member 14 increases. This improves the cooling efficiency of the connecting portion 30 by the refrigerant.

[0020] 5 is a plan view showing a main part of a modified example of the cooling structure 10 according to the first embodiment. In this modified example of the first embodiment, one wall surface of the insertion groove 24 has a protrusion 42 that presses at least a part of the connecting portion 30 inserted into the insertion groove 24 against the other wall surface of the insertion groove 24. By providing the protrusion 42 on one wall surface of the insertion groove 24, the connecting portion 30 is pressed against one wall surface of the insertion groove 24. Therefore, the cooling efficiency of the connecting portion 30 by the refrigerant is improved. The protrusions 42 may extend in a ridge-like shape from the opening side of the insertion groove 24 toward the inside of the flow channel 12, or may be in the form of a point.

[0021] Furthermore, the connecting portion 30 of the bus bar 26 may be embedded in the flow path forming member 14 by insert molding or the like, so that there is no clearance.

[0022] 3, the end faces of the flow paths 12 of the cooling structure 10 may be shapes other than a rectangle, such as a circle, an ellipse, or a polygon other than a rectangle. In order to ensure the flow rate of the refrigerant, the end faces of the flow paths 12 may be triangular in shape, with insertion grooves 24 provided at the vertices of the triangle, as shown in FIG. 6, at the end faces perpendicular to the direction in which the refrigerant flows in the upper inner wall 16.

[0023] There is no particular limitation on the type of coolant flowing through the flow path 12. Examples of the coolant include liquids such as water and organic solvents, and gases such as air. Water used as the coolant may contain components such as antifreeze.

[0024] Second Embodiment 7 and 8 are diagrams showing main parts of a cooling structure 44 according to a second embodiment, with Fig. 7 showing a plan view of the main parts of the cooling structure 44 and Fig. 8 showing a cross section of the cooling structure 44 taken along line CC in Fig. 7. In the cooling structure 44, at least a part of the connecting portion 30 is configured to contact the outer wall of the flow path forming member 14.

[0025] In the cooling structure 44, a portion of the flow path 12 between the fastening portions 36A and 36B has a convex structure 46 that protrudes toward the connecting portion 30 so that a portion of the connecting portion 30 comes into contact with the outer wall of the flow path forming member 14. A curved depression 48 is provided at the top of the convex structure 46.

[0026] 7 and 8, bus bar 26 has a flat plate shape. As shown in Fig. 8, the center of connecting portion 30 of bus bar 26, which connects terminal portion 28A and terminal portion 28B, protrudes toward the outer wall of flow path forming member 14, and the apex thereof contacts the outer wall of flow path forming member 14 along a curved depression 48.

[0027] When a current flows through the bus bar 26, the bus bar 26 generates heat and expands. Because the terminal portions 28A and 28B of the bus bar 26 are fastened to the flow path forming member 14 by the fastening portions 36A and 36B, respectively, the distance between the terminal portions 28A and 28B does not change significantly when the bus bar 26 generates heat and expands. On the other hand, because the connecting portion 30 protrudes toward the outer wall of the flow path forming member 14, the bus bar 26 generates heat and expands, increasing the amount of protrusion of the connecting portion 30 toward the outer wall of the flow path forming member 14. As a result, the connecting portion 30 comes into contact with the outer wall of the flow path forming member 14 more, as shown in FIG. 9 . As a result, the area of ​​the connecting portion 30 that comes into contact with the refrigerant via the flow path forming member 14 increases. This improves the cooling efficiency of the connecting portion 30 by the refrigerant.

[0028] Fig. 10 is a cross-sectional view showing a main part of a modified cooling structure 44 according to the second embodiment. Fig. 10 shows a cross section that is perpendicular to the direction in which the refrigerant flows in the flow passage 12 of the modified cooling structure 44 and passes through the centers of the bolts 32A and 32B. In the modified cooling structure 44 shown in Fig. 10, the bus bar 26 is arranged along a direction perpendicular to the direction in which the refrigerant flows in the flow passage 12. In a modified example of the second embodiment, in order to configure at least a portion of the connecting portion 30 to contact the outer wall of the flow path forming member 14, instead of providing the convex structure 46 in the flow path 12, a nut 34A constituting the fastening portion 36A and a nut 34B constituting the fastening portion 36B are embedded in the outer wall of the flow path forming member 14. In order to embed the nut 34A in the outer wall of the flow path forming member 14, the flow path forming member 14 is widened from the side inner wall 22 side in the thickness direction of the flow path forming member 14. In addition, in order to embed the nut 34B in the outer wall of the flow path forming member 14, the flow path forming member 14 is widened from the side inner wall 20 side in the thickness direction of the flow path forming member 14. The portions of the flow path forming member 14 that are widened toward the outer wall surface of the flow path forming member 14 may be only the portions where the nuts 34A and 34B are embedded, or the entire flow path forming member 14 may be widened. By embedding the nuts 34A and 34B in the outer wall of the flow path forming member 14, the cooling structure 44 can be made low in height. Furthermore, by embedding nuts 34A and 34B in the outer wall of flow path forming member 14, it is possible to maintain the shape of flow path 12 linearly while at least a portion of connecting portion 30 is in contact with the outer wall of flow path forming member 14. By maintaining the shape of flow path 12 linearly, the flow of refrigerant circulating through flow path 12 is less likely to be obstructed, increasing the amount of refrigerant circulating and improving cooling efficiency. In the modified cooling structure 44, a curved recess 48 is provided in the outer wall of the flow path forming member 14 at a location where at least a part of the connecting portion 30 contacts the outer wall of the flow path forming member 14. As shown in FIG. 10, the central portion of the connecting portion 30 of the bus bar 26 protrudes toward the outer wall of the flow path forming member 14, and its apex contacts the outer wall of the flow path forming member 14 along the curved depression 48.

[0029] In the second embodiment, the radius of curvature of the curved depressions (for example, depressions 48 at the apexes of the convex structures 46 in FIG. 8 ) in the outer wall of the flow path forming member 14 is preferably larger than the radius of curvature of the portions of the connecting portions 30 that come into contact with the curved depressions. By making the radius of curvature of the curved depressions in the outer wall of the flow path forming member 14 larger than the radius of curvature of the portions of the connecting portions 30 that come into contact with the curved depressions, it becomes possible to increase the contact area between the bus bar 26 and the outer wall of the connecting portions 30 when the bus bar 26 thermally expands, and this further improves cooling efficiency. The radius of curvature is set taking into consideration the type of metal constituting the bus bar, the amount of heat generated by the bus bar, and the like.

[0030] (Third embodiment) 11 is a cross-sectional view showing a main part of a cooling structure 50 according to a third embodiment, showing a cross section passing through the centers of bolts 32A and 32B of the cooling structure 50. In the cooling structure 50, at least a part of the connecting portion 30 is configured to contact the outer wall of the flow path forming member 14.

[0031] In the cooling structure 50, the portion of the outer wall of the flow path forming member 14 that contacts the connecting portion 30 is flat. The connecting portion 30 that constitutes the bus bar 26 in the cooling structure 50 has a flat portion 52 that protrudes toward the outer wall of the flow path forming member 14 and contacts the flat portion of the outer wall, a buffer portion 54A that is interposed between the flat portion 52 and the terminal portion 28A, and a buffer portion 54B that is interposed between the flat portion 52 and the terminal portion 28B. The flat portion 52 that constitutes part of the connecting portion 30 contacts the flat portion of the outer wall of the flow path forming member 14 in a flat state. A buffer region 56A is provided between the flat portion 52 and the base of the fastening portion 36A on the outer wall of the flow path forming member 14 (where the nut 34A is provided on the outer wall surface of the flow path forming member 14). In addition, a buffer region 56B is provided between the flat portion 52 and the base of the fastening portion 36B on the outer wall of the flow path forming member 14 (where the nut 34B is provided on the outer wall surface of the flow path forming member 14).

[0032] When a current flows through the bus bar 26, the bus bar 26 generates heat and expands. In the cooling structure 50, the flat portion 52 of the bus bar 26 in particular tends to expand in the direction of the arrow in Fig. 11. Even if the flat portion 52 expands in the direction of the arrow in Fig. 11, the expansion of the flat portion 52 is not hindered because the buffer region 56A is provided at the base of the fastening portion 36A and the buffer region 56B is provided at the base of the fastening portion 36B. This prevents the flat portion 52 from separating from the outer wall of the flow path forming member 14, improving the cooling efficiency of the refrigerant. In addition, a buffer portion 54A is provided between the flat portion 52 and the terminal portion 28A, and a buffer portion 54B is provided between the flat portion 52 and the terminal portion 28B, so that even if the flat portion 52 stretches in the direction of the arrow in Figure 11, the strain on the terminal portion 28A and the terminal portion 28B is reduced.

[0033] An example of the bus bar 26 used in the cooling structure 50 is one having a shape shown by the two-dot chain line in Fig. 11. In the bus bar 26 shown by the two-dot chain line in Fig. 11, the flat portion 52 protrudes in a curved shape toward the outer wall of the flow path forming member 14. Because the flat portion 52 protrudes in a curved shape, when the bus bar 26 is fastened to the cooling structure 50, the flat portion 52 can be easily brought into close contact with a planar portion of the outer wall of the flow path forming member 14 that contacts the connecting portion 30.

[0034] (Method of manufacturing flow path forming member) The flow path forming member 14 may be manufactured by any method, and can be manufactured by a typical molding method for a resin molded body, such as injection molding, die slide injection molding, blow molding, compression molding, transfer molding, extrusion molding, cast molding, etc. Since high positional accuracy is sometimes required in manufacturing the cooling structure, die slide injection molding is preferred. Furthermore, the portion of the flow passage forming member where the nut is provided may be manufactured separately by insert molding.

[0035] There are no particular limitations on the type of resin that constitutes the flow path forming member 14. Examples of resins include polyethylene-based resins, polypropylene-based resins (PP), composite polypropylene-based resins (PPC), polyphenylene sulfide-based resins (PPS), polyphthalamide-based resins (PPA), polybutylene terephthalate-based resins (PBT), epoxy-based resins, phenol-based resins, polystyrene-based resins, polyethylene terephthalate-based resins, polyvinyl alcohol-based resins, vinyl chloride-based resins, ionomer-based resins, polyamide-based resins, acrylonitrile-butadiene-styrene copolymer resins (ABS), and polycarbonate-based resins.

[0036] The resin constituting the flow path forming member 14 may contain an inorganic filler. Examples of inorganic fillers include silica, alumina, zircon, magnesium oxide, calcium silicate, calcium carbonate, potassium titanate, silicon carbide, silicon nitride, boron nitride, beryllia, and zirconia. Furthermore, examples of inorganic fillers having flame retardant properties include aluminum hydroxide and zinc borate.

[0037] (Use of cooling structure) The cooling structure of the present disclosure is effective for cooling bus bars that electrically connect electronic components such as power modules having multiple power semiconductors and capacitors in vehicles equipped with motors, such as hybrid vehicles and electric vehicles. [Explanation of symbols]

[0038] 10, 44, 50 cooling structure 12 Flow path 14 Flow path forming member 16 Upper inner wall 18 Lower inner wall 20, 22 Side inner wall 24 Insertion groove 26, 38, 40 busbars 28A, 28B, 28C, 28D terminal section 30 Connecting part 32A, 32B Volts 34A, 34B nuts 36A, 36B fastening section 42 Protrusion 46 Convex structure 48 depression 52 Flat area 54A, 54B buffer section 56A, 56B buffer area

Claims

1. a flow path forming member made of resin that forms a flow path through which a coolant flows; A bus bar having a plurality of terminal portions and a connecting portion connecting the plurality of terminal portions; a fastening portion provided on an outer wall surface of the flow path forming member and configured to fix the terminal portions of the bus bar to the flow path forming member, A cooling structure in which at least a portion of the connecting portion is in contact with the refrigerant via the flow path forming member.

2. the flow passage forming member has an insertion groove recessed from an outer wall surface side of the flow passage forming member toward the flow passage, The cooling structure according to claim 1 , wherein at least a portion of the connecting portion is inserted into the insertion groove.

3. 3. The cooling structure according to claim 2, wherein one wall surface of the insertion groove has a protrusion for pressing at least a part of the connecting portion inserted into the insertion groove against the other wall surface of the insertion groove.

4. The cooling structure according to claim 1 , wherein at least a portion of the connecting portion is in contact with an outer wall of the flow passage forming member.

5. The cooling structure according to claim 4 , wherein a portion of the outer wall of the flow passage forming member that contacts the connecting portion has a curved recess, and at least a portion of the connecting portion contacts the outer wall of the flow passage forming member along the curved recess.

6. The cooling structure according to claim 5 , wherein a radius of curvature of the curved recess in the outer wall of the flow passage forming member is larger than a radius of curvature of a portion of the connecting portion that contacts the curved recess.

7. The cooling structure according to claim 4 , wherein a portion of the outer wall of the flow passage forming member that comes into contact with the connecting portion is flat, and at least a portion of the connecting portion comes into contact with the flat portion of the outer wall while forming a flat surface.

8. The cooling structure according to claim 7 , wherein an outer wall of the flow passage forming member has a buffer region in a direction in which the flat region of the connecting portion expands when the bus bar thermally expands.

9. a flow path forming member made of resin that forms a flow path through which a coolant flows; A bus bar having a plurality of terminal portions and a connecting portion connecting the plurality of terminal portions; a fastening portion provided on an outer wall surface of the flow path forming member and configured to fix the terminal portions of the bus bar to the flow path forming member, A cooling structure having a structure in which, when the bus bar thermally expands, an area of ​​the connecting portion that comes into contact with the refrigerant via the flow path forming member increases.

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