Heat exchanger for cooling

Abstract

To provide a cooling heat exchanger having a novel structure capable of ensuring strength and stabilizing quality while effectively implementing reduction in weight due to the utilization of a synthetic resin.SOLUTION: In a cooling heating exchanger 10 in which a metal plate 12 to be superimposed on a cooling object 36 and a plate-shaped resin member 14 having a concave groove 20 are superimposed and fixed onto each other, and a cooling flow path 34 through which a heat medium flows is formed between the metal plate 12 and the resin member 14 by covering an opening of the concave groove 20 with the metal plate 12, a bottom surface 28 of the cooling flow path 34 made of the resin member 14 has a concave curved surface in a cross-section perpendicular to a flow path length direction.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a cooling heat exchanger used for cooling an object to be cooled, such as a battery pack, in an electrically powered vehicle such as an electric automobile. [Background technology]

[0002] In electric vehicles, such as electric cars and hybrid cars, the objects to be cooled, such as battery packs and electronic devices, generate more heat due to their miniaturization and high performance, and cooling performance is becoming increasingly important. Conventionally, cooling heat exchangers have been used to cool battery packs and the like, with a cooling flow path formed between metal plates that are stacked on top of each other. In this cooling heat exchanger, one plate is stacked on the object to be cooled, such as a battery pack, and the object to be cooled is cooled by cooling the one plate with a refrigerant flowing through the cooling flow path.

[0003] In addition, since there is a strong demand for lightweight vehicles in electric vehicles, weight reduction of cooling heat exchangers is also being considered. For example, International Publication No. 2020 / 196878 (Patent Document 1) proposes that one plate that is overlapped with the object to be cooled and requires high thermal conductivity is made of metal, and the other plate that does not require thermal conductivity is made of a resin member made of synthetic resin with a specific gravity smaller than that of metal. In Patent Document 1, the resin member is a box body that opens upward, and a flow path forming rib is provided integrally with the box body inside the box body. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2020 / 196878 Summary of the Invention [Problem to be solved by the invention]

[0005] However, after investigations by the present inventors, it was found that in the structure of Patent Document 1, the weight of the resin member becomes large, and there is a risk that weight reduction, which is one of the purposes of changing the other plate from metal to synthetic resin, may not be fully achieved.

[0006] That is, when a box body with flow path forming ribs provided therein as in Patent Document 1 is to be formed from synthetic resin, if a wall thickness is set that can ensure sufficient quality stability and strength (deformation rigidity), the weight of the resin member increases, and the advantage of weight reduction may not be fully obtained. On the other hand, if the wall thickness of each part of the box body and flow path forming ribs is reduced in order to reduce the weight of the resin member, molding defects may occur easily during injection molding, making it difficult to manufacture with stable quality, or strength against the liquid pressure of the refrigerant flowing through the cooling flow path and against external input may not be ensured.

[0007] An object of the present invention is to provide a heat exchanger for cooling having a novel structure, which can effectively reduce weight by using synthetic resin, while ensuring strength and stabilizing quality. [Means for solving the problem]

[0008] The following describes preferred embodiments for understanding the present invention, but the embodiments described below are merely illustrative and may be combined with one another as appropriate, and the multiple components described in each embodiment may be recognized and used independently as far as possible, and may also be combined with any of the components described in another embodiment as appropriate. As a result, the present invention is not limited to the embodiments described below, and various other embodiments may be realized.

[0009] The first aspect is a cooling heat exchanger in which a metal plate to be placed on an object to be cooled and a plate-shaped resin member having a groove are placed on top of each other and fixed to each other, and the opening of the groove is covered by the metal plate to form a cooling flow path between the metal plate and the resin member through which a heat medium flows, and the bottom surface of the cooling flow path made of the resin member has a concave curved surface in a cross section perpendicular to the length of the flow path.

[0010] In the cooling heat exchanger constructed according to this embodiment, the resin member is plate-shaped, and compared with a box-shaped member, the number of bent portions in the cavity of the molding die is reduced, so that the resin material is easily filled into the entire cavity, and molding defects such as sink marks and voids are less likely to occur. In addition, since the resin member is plate-shaped, stress concentration at the bent portions, which can be a problem in the case of a box-shaped member, is avoided, and the resin member can be advantageously made thinner.

[0011] Since the bottom surface of the cooling flow path has a concave curved surface, the acting direction of the pressure exerted on the concave curved surface by the heat medium flowing through the cooling flow path is not constant throughout, but is dispersed in a direction perpendicular to the wall inner surface at each part. Therefore, the maximum value of the force based on the pressure acting on the bottom surface of the cooling flow path is suppressed, and the pressure resistance performance of the part of the wall part of the cooling flow path made of a resin member is improved. As a result, it is possible to make the resin member thinner while maintaining the pressure resistance strength of the wall part of the cooling flow path, and it is possible to realize a weight reduction of the cooling heat exchanger.

[0012] In a second aspect, in the cooling heat exchanger described in the first aspect, the metal plate is provided with a groove-shaped bead portion that opens toward the resin member and protrudes to the opposite side of the resin member, and the bead portion forms a wall portion of the cooling flow path.

[0013] According to the cooling heat exchanger constructed according to this embodiment, the cross-sectional area of ​​the cooling flow path is ensured by the bead portion of the metal plate, so that the cross-sectional area of ​​the groove in the resin member can be made smaller, and the resin member can be made thinner to achieve weight reduction. In addition, the provision of the bead portion in the metal plate is expected to reinforce the deformation rigidity of the metal plate, so that the weight can be reduced by making the metal plate thinner.

[0014] A third aspect is a cooling heat exchanger according to the first or second aspect, wherein the bottom surface of the cooling flow passage is configured to include the concave curved surface that is continuous over the entire width direction of the flow passage.

[0015] In a cooling heat exchanger constructed according to this embodiment, the concave curved surface is provided over the entire width of the bottom surface of the cooling flow passage, thereby more effectively improving the pressure resistance of the resin member by dispersing the direction of pressure action of the heat medium on the bottom surface of the cooling flow passage.

[0016] Furthermore, at both ends of the cooling flow passage in the flow passage width direction, the thickness dimension in the plate thickness direction of the resin member constituting the bottom wall portion of the cooling flow passage is secured, and the thickness dimension of the resin member decreases toward the middle of the cooling flow passage in the flow passage width direction. This makes it easier for the resin material to be filled into the molding portion of the bottom wall portion of the cooling flow passage in the molding cavity of the resin member, thereby avoiding defective molding of the bottom wall portion and stabilizing quality.

[0017] In a fourth aspect, in the cooling heat exchanger according to the third aspect, the curvature of the concave curved surface is set to 0.5 or less.

[0018] In a cooling heat exchanger constructed according to this embodiment, the ratio of the flow path width dimension to the flow path depth dimension of the cooling flow path is large, so that even if the plate thickness of the resin member is made thin, the flow path cross-sectional area of ​​the cooling flow path can be secured, and the weight of the resin member can be reduced.

[0019] In a fifth aspect, in the cooling heat exchanger described in the first or second aspect, the bottom surface of the cooling flow passage is configured to include a plurality of the concave curved surfaces arranged in parallel in the flow passage width direction.

[0020] According to the cooling heat exchanger constructed according to this embodiment, the pressure resistance of the resin member is improved by dispersing the direction of the pressure of the heat medium by each concave curved surface. In addition, the recessed curved surfaces are spaced apart from each other in the length direction of the cooling flow path, so that the deformation rigidity of the resin member against bending deformation can be improved.

[0021] In a sixth aspect, in the cooling heat exchanger according to the fifth aspect, the curvature of the concave curved surface is set to 2.0 or less.

[0022] In a cooling heat exchanger constructed according to this embodiment, the ratio of the flow path width dimension to the flow path depth dimension of the cooling flow path is large, so that even if the plate thickness of the resin member is made thin, the flow path cross-sectional area of ​​the cooling flow path can be secured, and the weight of the resin member can be reduced.

[0023] A seventh aspect is a cooling heat exchanger according to any one of the first to sixth aspects, wherein the metal plate is made of either an aluminum alloy or stainless steel, and the thickness dimension of the resin member in the portion outside the groove is less than 2.6 times the thickness dimension of the metal plate when the metal plate is made of an aluminum alloy, and is less than 8.8 times the thickness dimension of the metal plate when the metal plate is made of stainless steel.

[0024] In a cooling heat exchanger constructed according to this embodiment, the synthetic resin member is lighter than a metal plate, making it lighter than a cooling heat exchanger of the conventional structure in which two metal plates are stacked on top of each other.

[0025] In an eighth aspect, in the cooling heat exchanger described in the seventh aspect, the plate thickness dimension of the resin member in the portion outside the groove is within a range of 1.0 to 2.5 times the plate thickness dimension of the metal plate when the metal plate is made of an aluminum alloy, and within a range of 3.5 to 8.7 times the plate thickness dimension of the metal plate when the metal plate is made of stainless steel.

[0026] According to the cooling heat exchanger having the structure according to this aspect, the strength of the resin member can be ensured while the resin member can be made lighter than a metal plate.

[0027] A ninth aspect is a cooling heat exchanger according to any one of the first to eighth aspects, wherein the minimum thickness dimension of the bottom wall portion of the groove is within the range of 0.3 times or more and 1.0 times or less the plate thickness dimension of the resin member in the portion outside the groove.

[0028] With a cooling heat exchanger constructed according to this embodiment, the strength of the resin member is ensured by preventing the resin member from becoming excessively thin at the portion where the groove is formed, while the depth of the groove is ensured, thereby making it possible to set the flow path cross-sectional area of ​​the cooling flow path sufficiently large. Effect of the Invention

[0029] According to the present invention, in a cooling heat exchanger, it is possible to effectively realize a reduction in weight by using synthetic resin, while ensuring strength and stabilizing quality. [Brief description of the drawings]

[0030] [Figure 1] FIG. 1 is an exploded perspective view showing a cooling heat exchanger according to a first embodiment of the present invention; [Diagram 2] Cross-sectional view of the cooling heat exchanger shown in Figure 1 [Diagram 3] FIG. 1 is a cross-sectional view showing a cooling heat exchanger according to a second embodiment of the present invention. [Figure 4] FIG. 11 is a cross-sectional view showing a cooling heat exchanger according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0032] Fig. 1 shows a cooling heat exchanger 10 as a first embodiment of the present invention. As shown in Fig. 2, the cooling heat exchanger 10 has a structure in which a metal plate 12 and a resin plate 14 as a resin member are overlapped and fixed to each other, and Fig. 1 shows the metal plate 12 and the resin plate 14 in an exploded state in which they are separated from each other. In the following description, the up-down direction refers to the up-down direction in Fig. 2, which is the overlapping direction of the metal plate 12 and the resin plate 14, the front-rear direction refers to the left-right direction in Fig. 2, and the left-right direction refers to the direction perpendicular to the paper surface in Fig. 2.

[0033] The metal plate 12 is a plate-like member that is placed on the object to be cooled (the battery pack 36 described later), and is made of a metal such as an aluminum alloy or stainless steel. The metal plate 12 in this embodiment is made of an aluminum alloy. The metal plate 12 has a rectangular plate shape as a whole, and in this embodiment, is rectangular when viewed from the top and bottom, with the front-to-back direction being the long side direction and the left-to-right direction being the short side direction.

[0034] The metal plate 12 is provided with first bead portions 16 as a plurality of bead portions. The first bead portions 16 are formed in a substantially semicircular arc shape in the cross section shown in Fig. 2, and open in a groove shape on the lower surface of the metal plate 12, and protrude in a tapered convex shape on the upper surface of the metal plate 12. In this embodiment, three first bead portions 16, 16, 16 extending linearly in the long side direction (front-rear direction) of the metal plate 12 are provided on the metal plate 12. The three first bead portions 16, 16, 16 are provided in the central portion of the metal plate 12, and are formed in a line spaced apart from each other in the short side direction of the metal plate 12.

[0035] The metal plate 12 is provided with a plurality of second bead portions 18. The second bead portions 18 have a substantially semicircular cross-sectional shape similar to the first bead portions 16, and are groove-shaped on the lower surface of the metal plate 12, and protrude in a tapered convex shape on the upper surface of the metal plate 12. In this embodiment, two second bead portions 18, 18 extending linearly in the left-right direction (short side direction) of the metal plate 12 are provided on the metal plate 12. The two second bead portions 18, 18 are provided in the center portion in the left-right direction at both ends of the front-rear direction (long side direction) of the metal plate 12. The two second bead portions 18, 18 are located on both outer sides in the front-rear direction with respect to the three first bead portions 16, 16, 16. The metal plate 12 provided with the first and second bead portions 16, 18 is formed, for example, by pressing a metal sheet.

[0036] The metal plate 12 has a substantially constant thickness t1 throughout. The thickness t1 of the metal plate 12 is preferably within a range of 0.3 mm to 1.5 mm, and more preferably within a range of 0.4 mm to 1.0 mm. The fact that the thickness of the metal plate 12 is constant means that there are no obvious thick or thin portions. For example, the difference in thickness of the first and second bead portions 16 and 18 formed by press working, which may be slightly thin, can be ignored, and the metal plate 12 of this embodiment can be considered to have a substantially constant thickness.

[0037] The resin plate 14 is a plate-like member formed of synthetic resin such as polyamide, polyacetal, polycarbonate, polyester, polyethylene, polypropylene, etc. The resin plate 14 has a rectangular shape that generally corresponds to the metal plate 12 when viewed in the vertical direction. The lower surface of the resin plate 14 has a generally flat shape without significant irregularities, and is a plane that extends generally perpendicular to the vertical direction. The resin plate 14 may be a reinforced resin member reinforced with glass fiber, carbon fiber, etc.

[0038] The resin plate 14 is formed with a groove 20 that opens to the upper surface. As shown in FIG. 1, the groove 20 includes three intermediate grooves 22, 22, 22 extending in the front-rear direction of the resin plate 14, two outer grooves 24, 24 extending in the front-rear direction on both the left and right outer sides of the three intermediate grooves 22, 22, 22, and two connecting grooves 26, 26 extending in the left-right direction between the two outer grooves 24, 24 and connecting the three intermediate grooves 22, 22, 22 to each other at both front and rear ends. The two outer grooves 24, 24 protrude outward in the front-rear direction from the two connecting grooves 26, 26 at one end in the front-rear direction. The upper surface of the resin plate 14 is a flat surface that extends approximately parallel to the lower surface in a portion outside the groove 20.

[0039] As shown in FIG. 2, the bottom surface 28 of the groove 20 is formed of a concave curved surface that is concave upward in a cross section perpendicular to the length direction. In this embodiment, the bottom surface 28 of the groove 20 is formed of a concave curved surface that is continuous over the entire groove width direction. The curvature of the bottom surface 28 of the groove 20 is preferably 0.5 or less. The inner groove surface of the groove 20 may have a bottom surface 28 and side surfaces 30, 30 as in this embodiment, or may be formed of a bottom surface 28 that is entirely a concave curved surface. In this embodiment, the bottom surface 28 of the groove 20 is formed into an arc cross-sectional shape having a substantially constant curvature, but the curvature may change gradually or in stages.

[0040] The resin plate 14 has a substantially constant thickness t2 at a portion outside the groove 20, and the thickness t2 is the maximum thickness. The resin plate 14 is partially thin at the portion where the groove 20 is formed. The bottom surface 28 of the groove 20 has its lowest point at the center in the groove width direction (left and right direction in FIG. 2), and the resin plate 14 is thinnest at the center in the groove width direction at the portion where the groove 20 is formed. The minimum thickness t3 of the resin plate 14 at the bottom wall of the groove 20 is desirably within a range of 0.3 to 1.0 times the thickness t2 of the resin plate 14.

[0041] The thickness dimension t2 of the resin plate 14 is desirably less than 2.6 times the thickness dimension t1 of the metal plate 12. The thickness dimension t2 of the resin plate 14 is preferably within a range of 1.0 to 2.5 times, and more preferably 1.5 to 2.2 times, the thickness dimension t1 of the aluminum alloy metal plate 12. This allows the resin plate 14 to be lighter than the metal plate 12, and the cooling heat exchanger 10 can be made lighter than when the upper and lower plate-like members that are stacked together to form the cooling flow passage 34 (described later) are both made of a metal member equivalent to the metal plate 12.

[0042] The groove width of the groove 20 is larger than the maximum depth, and the groove width is preferably within a range of 2 to 10 times the maximum depth. The maximum depth of the groove 20 is preferably within a range of 1.2 to 2 times the minimum depth.

[0043] As shown in Fig. 2, the metal plate 12 and the resin plate 14 are overlapped with each other in the up-down direction, and an adhesive layer 32 is formed between the overlapping surfaces at the portion outside the recessed groove 20, and they are bonded to each other. Note that the means for fastening the metal plate 12 and the resin plate 14 is not limited to adhesion, and may be, for example, welding, or mechanical fixing with rivets, screws, etc. Also, in Fig. 2, the thickness dimensions of the metal plate 12, the resin plate 14, and the adhesive layer 32 are not necessarily in actual proportion, and for example, the thickness dimension of the adhesive layer 32 is drawn particularly large for ease of viewing.

[0044] The metal plate 12 is superposed on the upper surface of the resin plate 14, and the opening of the groove 20 is covered by the metal plate 12, thereby forming a cooling flow passage 34 between the superposed surfaces of the metal plate 12 and the resin plate 14. The cooling flow passage 34 has a flow passage width dimension, which is the groove width dimension of the groove 20, larger than a flow passage depth dimension, which is the distance between the opposing surfaces of the lower surface of the metal plate 12 and the bottom surface 28 of the groove 20. The cooling flow passage 34 has a top wall portion (upper wall portion) formed by the metal plate 12. The cooling flow passage 34 has a bottom wall portion (lower wall portion) formed by the resin plate 14, and a bottom surface formed by the bottom surface 28 of the groove 20. The cooling flow passage 34 has a side wall portion formed by the side surface 30 of the groove 20 and the adhesive layer 32.

[0045] The first bead portions 16, 16, 16 of the metal plate 12 are located on the openings of the intermediate groove portions 22, 22, 22 of the groove 20, and constitute the top wall portion of the cooling flow passage 34. The first bead portions 16, 16, 16, which are groove-shaped and open to the lower surface, increase the flow passage cross-sectional area of ​​the cooling flow passage 34. In this way, the flow passage cross-sectional area of ​​the cooling flow passage 34 in the portion formed by the intermediate groove portions 22, 22, 22 is ensured to be large by using the first bead portions 16, 16, 16 of the metal plate 12. Therefore, even if the width dimensions of the intermediate groove portions 22, 22, 22 are relatively small, the flow passage cross-sectional area of ​​the cooling flow passage 34 in the portion formed by the intermediate groove portions 22, 22, 22 can be sufficiently ensured. The width dimension of the first bead portion 16 is smaller than the groove width dimension of the intermediate groove portion 22 of the groove 20, and is preferably half or less of the groove width dimension of the intermediate groove portion 22.

[0046] The second bead portions 18, 18 are provided at positions outside the recessed groove 20, and do not form walls of the cooling flow passage 34. Adhesive fills the groove-shaped spaces formed below the second bead portions 18, 18, and the bonding area of ​​the adhesive layer 32 to the metal plate 12 is increased by the second bead portions 18, 18. The adhesive layer 32 has a substantially constant thickness in the portions outside the second bead portions 18, 18, and is thicker in the portions where the second bead portions 18, 18 are formed than in other portions.

[0047] Both ends of the cooling flow passage 34 formed by one end of each of the two outer grooves 24, 24 are connected to an external pipe (not shown) through external ports (not shown) on the inlet side and the outlet side provided in the metal plate 12. A refrigerant as a heat medium is supplied to the cooling flow passage 34 from the external port on the inlet side, and the refrigerant in the cooling flow passage 34 is discharged to the outside from the external port on the outlet side. As a result, the refrigerant flows through the cooling flow passage 34, and the metal plate 12 constituting the wall part of the cooling flow passage 34 is cooled by the refrigerant. The external port may be provided in the resin plate 14. The external port may be provided integrally with the metal plate 12 or the resin plate 14, or may be a separate part from the plates 12, 14 and attached to at least one of the plates 12, 14.

[0048] The coolant is a fluid that can flow through the cooling flow passage 34. The type of fluid used as the coolant is not particularly limited, but for example, liquids or gases such as water, ammonia, and air are preferably used. The metal plate 12 and the resin plate 14 are fixed fluid-tightly around the cooling flow passage 34 between the overlapping surfaces, thereby preventing the coolant in the cooling flow passage 34 from leaking out to the outside. In this embodiment, the fluid-tightness between the overlapping surfaces of the metal plate 12 and the resin plate 14 is ensured by the adhesive layer 32, but when mechanical fixing by rivets, screws, etc. is adopted, the liquid-tightness of the cooling flow passage 34 can also be ensured by, for example, disposing a seal rubber between the overlapping surfaces of the metal plate 12 and the resin plate 14.

[0049] The refrigerant is pumped by a pump (not shown) and flows through the cooling flow passage 34, so that the pressure of the refrigerant acts on the inner wall surface of the cooling flow passage 34. In particular, a large force based on the pressure of the refrigerant acts on the bottom surface 28 and the top surface, which have a large area in the wall surface of the cooling flow passage 34. Since the top surface of the wall surface of the cooling flow passage 34 is made of the metal plate 12, damage such as cracks is unlikely to occur even if a large force based on the pressure of the refrigerant acts on the top surface. On the other hand, since the bottom surface 28 of the wall surface of the cooling flow passage 34 is made of the resin plate 14 made of synthetic resin, damage such as cracks is likely to become a problem when a large force based on the pressure of the refrigerant acts on the bottom surface 28. Here, the bottom surface 28 of the cooling flow passage 34 is made of a concave curved surface, and the acting direction of the pressure of the refrigerant on the bottom surface 28 is not constant but changes in the groove width direction, so that the maximum value of the force based on the pressure acting on the bottom surface 28 is suppressed.

[0050] That is, if the bottom surface of the cooling flow passage 34 is a flat surface perpendicular to the up-down direction, all pressures acting on the bottom surface act in the same downward direction, and the resultant force is the product of the area of ​​the bottom surface and the pressure. On the other hand, if the bottom surface 28 of the cooling flow passage 34 is a concave curved surface, the directions of the pressure acting on the bottom surface 28 are perpendicular to the bottom surface 28 at each portion, and are different from each other, so that the downward force, which is the maximum force acting on the bottom surface 28 due to the pressure of the refrigerant, is smaller than when the bottom surface is a flat surface. Therefore, the maximum value of the force acting based on the pressure of the refrigerant is reduced at the bottom wall portion of the groove 20 in the resin plate 14, making it easier to ensure the pressure resistance of the bottom wall portion of the groove 20, which is thinner than other portions.

[0051] The cooling heat exchanger 10 is used, for example, to cool a battery pack 36 in an electric vehicle such as an electric vehicle (BEV) or a hybrid car. That is, as shown in Fig. 2, the battery pack 36 as an object to be cooled is overlaid on the metal plate 12 via a thermally conductive layer 38, and heat is exchanged between the metal plate 12, which is cooled by a refrigerant flowing through a cooling flow passage 34, and the battery pack 36, which is a heat generating body, via the thermally conductive layer 38, thereby cooling the battery pack 36.

[0052] The thermally conductive layer 38 is provided to cover the upper surface of the metal plate 12, and is, for example, in the form of a sheet or gel. The thermally conductive layer 38 is formed of a material with high thermal conductivity, and for example, a thermally conductive resin in which a metal powder with high thermal conductivity, such as copper or silver, is mixed with a base material made of synthetic resin, can be used. The thermally conductive layer 38 desirably has a sufficient thickness and compressive deformability so that it can fill the gap between the overlapping surfaces of the upper surface of the metal plate 12 and the lower surface of the battery pack 36. In this embodiment, since the lower surface of the battery pack 36 is made substantially flat, the thickness and compressive deformability of the thermally conductive layer 38 are set so that the upper surface is kept flat while the lower surface can follow the unevenness of the upper surface of the metal plate 12 caused by the first and second bead portions 16 and 18. The thermally conductive layer 38 may be formed in advance with an upper surface corresponding to the lower surface of the battery pack 36 and a lower surface corresponding to the upper surface of the metal plate 12, in which case the required level of compressive deformability can be reduced. The thermally conductive layer 38 is preferably sandwiched between the metal plate 12 and the resin plate 14 and thereby deformed into a shape corresponding to the overlapping surfaces of the metal plate 12 and the resin plate 14 .

[0053] 3 shows a cooling heat exchanger 40 according to a second embodiment of the present invention. The cooling heat exchanger 40 has a laminated structure in which a metal plate 12 and a resin plate 42 as a resin member are overlapped and bonded to each other with an adhesive layer 32. In the following description, the same reference numerals are used in the drawings to denote members and parts that are substantially the same as those in the first embodiment, and description thereof will be omitted.

[0054] The resin plate 42 is formed with a groove 44 that opens to the upper surface. The groove 44 of this embodiment is configured to include a plurality of parallel groove portions 46. The parallel groove portions 46 open to the upper surface of the resin plate 42 and extend in the length direction of the groove 44, and a plurality of parallel groove portions 46 are arranged in parallel in the groove width direction of the groove 44. In the groove 44 of this embodiment, five parallel groove portions 46, 46, 46, 46, 46 are arranged in parallel, but the number of parallel groove portions 46 provided in the groove 44 is not particularly limited as long as it is a plurality. In this embodiment, the five parallel groove portions 46, 46, 46, 46, 46 are arranged at approximately regular intervals from each other. In addition, in this embodiment, the parallel groove portions 46 are separated from each other in the groove width direction of the groove 44, but may be arranged adjacent to each other in the groove width direction of the groove 44, for example. The parallel groove portions 46 may be provided over the entire length of the recessed groove 44, or may be provided partially in the length direction of the groove.

[0055] The bottom surfaces 48 of the parallel groove portions 46 are each formed as a concavely curved surface that is recessed in a concave shape in a cross section perpendicular to the longitudinal direction of the groove 44 shown in Fig. 3. Thus, the bottom surface of the groove 44 has a plurality of concavely curved surfaces arranged in parallel in the groove width direction. The depth dimension of each of the parallel groove portions 46 is maximum at approximately the center in the width direction. The curvature of the bottom surfaces 48 of the parallel groove portions 46 is desirably 2.0 or less.

[0056] In this embodiment, the multiple parallel groove portions 46 are approximately the same in size, depth, radius of curvature, etc., but the sizes, depths, radius of curvature, and other shapes of the multiple parallel groove portions 46 may be different from one another.

[0057] A rib-shaped protrusion 50 is formed between two parallel groove-like portions 46, 46 adjacent to each other in the groove width direction of the groove 44. The rib-shaped protrusion 50 extends continuously in the groove length direction of the groove 44, and the protruding tip surface is a plane that spreads approximately perpendicular to the up-down direction. The width dimension of the protruding tip surface of the rib-shaped protrusion 50 is preferably smaller than the width dimension of the parallel groove-like portion 46. In addition, it is desirable that the protruding tip surface of the rib-shaped protrusion 50 is located below the upper surface of the portion of the resin plate 42 that is outside the groove 44. However, the protruding tip surface of the rib-shaped protrusion 50 may be located on the same plane as the upper surface of the portion of the resin plate 42 that is outside the groove 44, and in this case, the protruding tip surface of the rib-shaped protrusion 50 is separated from the lower surface of the metal plate 12 by the thickness of the adhesive layer 32. Furthermore, when two adjacent parallel groove portions 46, 46 are provided close to each other in the groove width direction of the recessed groove 44, the protruding tip of the rib-shaped protrusion 50 can be a tapered ridge line rather than a flat surface.

[0058] According to the cooling heat exchanger 40 of this embodiment, the bottom surface of the recessed groove 44 is configured to include bottom surfaces 48 of the parallel groove-like portions 46, and the bottom surfaces 48 of the parallel groove-like portions 46 are each formed as a concave curved surface. Therefore, the direction of action of the refrigerant pressure on the bottom surfaces 48 of the parallel groove-like portions 46 differs depending on the position in the groove width direction, and the dispersion of the pressure action direction can lower the required level of pressure resistance for the bottom wall portion (lower wall portion) of the recessed groove 44. As a result, the resin plate 42 can be made thinner, and the cooling heat exchanger 40 can be made lighter in weight.

[0059] In addition, the curvature of the bottom surface 48 of each of the parallel groove-like portions 46 can be adjusted and set with greater freedom without being restricted by the overall width dimension of the recessed groove 44. This makes it easier to appropriately set the curvature of the bottom surface 48 in consideration of the thickness dimension of each portion of the resin plate 42, the required strength, and the like.

[0060] In addition, by forming a rib-like protrusion 50 between adjacent parallel groove portions 46, 46 in the groove width direction of the recessed groove 44, the bending deformation rigidity of the resin plate 42 is improved, making it easier to prevent the resin plate 42 from deflecting due to the action of external forces.

[0061] Although the embodiment of the present invention has been described in detail above, the present invention is not limited by the specific description. For example, the shape and structure of the cooling flow passage are not particularly limited. For example, a groove corresponding to the groove 20 of the resin plate 14 may be formed on the lower surface of the metal plate 12 so as to open thereto, and these grooves may cooperate to form the cooling flow passage. In addition, the flow passage shape of the cooling flow passage may be a spiral or serpentine shape.

[0062] The curvature of the concave curved surface constituting the bottom surface 28 of the cooling flow passage 34 (groove 20) does not need to be constant, and may vary in the flow passage width direction or in the flow passage length direction. In addition, the entire bottom surface 28 of the cooling flow passage 34 does not need to be composed of a concave curved surface, as long as at least a part of the bottom surface 28 is made into a concave curved surface.

[0063] For example, it is also possible to form the parallel groove portion 46 of the second embodiment so as to open into the concave curved surface (bottom surface 28) of the groove 20 of the first embodiment, and the structure of the first embodiment and the structure of the second embodiment can be adopted in combination.

[0064] The bead portion of the metal plate 12 is not essential. In addition, the bead portion only needs to be provided on the opening of the groove 20, and can also be provided on the opening of the outer groove portion 24 or the connecting groove portion 26. Therefore, it is also possible to form a bead portion on the metal plate 12 that extends over the entire length of the groove 20.

[0065] As shown as the second bead portion 18 in the above embodiment, the bead portion of the metal plate 12 is not limited to being formed only on the opening of the groove 20, but can also be provided in a portion outside the opening of the groove 20. Furthermore, even in an embodiment in which a bead portion is provided on the opening of the groove 20, it is also possible to provide, for example, a plurality of bead portions extending parallel to the groove length direction on the opening of the groove 20.

[0066] Although the metal plate 12 in the above embodiment is made of an aluminum alloy, the metal material forming the metal plate is not particularly limited, and for example, stainless steel may be suitably used. When a stainless steel metal plate is used, the thickness of the resin plate 14 at the portion outside the groove 20 is preferably less than 8.8 times the thickness of the metal plate, and more preferably, is within a range of 3.5 to 8.7 times the thickness of the metal plate. This makes the resin plate 14 lighter than the stainless steel metal plate, and therefore a cooling heat exchanger lighter than a cooling heat exchanger made of two stainless steel metal plates stacked together can be obtained.

[0067] In the above embodiment, the lower surface of the resin plate 14 is flat, and the thickness dimension of the resin plate 14 is small in the portion where the groove 20 is formed. However, for example, the lower surface of the resin plate in the portion where the groove is formed may be a curved surface corresponding to the bottom surface of the groove. Specifically, as in a cooling heat exchanger 60 as a third embodiment of the present invention shown in FIG. 4, the lower surface of a resin plate 62 as a resin member may be a curved surface 64 that protrudes downward in the portion where the groove 20 is formed. The curved surface 64 has a cross-sectional shape corresponding to the bottom surface 28 of the groove 20 that is a concave curved surface, and the bottom wall portion of the groove 20 has a curved cross-sectional shape of an arc that is convex downward. This can prevent the thickness dimension of the resin plate 62 from becoming locally thin in the portion where the groove 20 is formed, making it easier to ensure the pressure resistance and bending rigidity of the resin plate 62.

[0068] It is also possible to partially reinforce the resin plate 14 by insert-molding a reinforcing member such as a metal plate into the bottom wall of the recessed groove 20 in the resin plate 14. According to such a structure in which the resin plate 14 is partially reinforced with a reinforcing member, the necessary pressure resistance and bending rigidity can be easily achieved while reducing the thickness of the resin plate 14 and reducing its weight by reinforcing the parts where pressure resistance and bending rigidity are likely to be problematic.

[0069] The object to be cooled is not limited to the battery pack 36 exemplified in the above embodiment, but may be, for example, a computing device or a storage device in which heat generation during operation is likely to be a problem. [Explanation of symbols]

[0070] 10 Cooling heat exchanger (first embodiment) 12 Metal Plate 14 Resin plate (resin part) 16 First bead part (bead part) 18 Second bead section 20 Groove 22 Intermediate groove 24 Outer groove 26 Connection groove 28 Bottom surface (concave curved surface) 30 Side 32 Adhesive layer 34 Cooling Channel 36 Battery pack (to be cooled) 38 Thermal Conduction Layer 40 Cooling heat exchanger (second embodiment) 42 Resin plate (resin part) 44 Groove 46 Parallel grooves 48 Bottom surface (concave curved surface) 50 Rib-like protrusion 60 Cooling heat exchanger (second embodiment) 62 Resin plate (resin part) 64 Curved Surfaces

Claims

1. A heat exchanger for cooling, comprising a metal plate to be placed on an object to be cooled and a plate-shaped resin member having a groove, which are placed on top of each other and fixed to each other, and an opening of the groove is covered with the metal plate to form a cooling flow path through which a heat medium flows between the metal plate and the resin member, A heat exchanger for cooling, wherein a bottom surface of the cooling flow passage made of the resin member has a concave curved surface in a cross section perpendicular to a length direction of the flow passage.

2. 2. The cooling heat exchanger according to claim 1, wherein the metal plate has a groove-shaped bead portion that opens toward the resin member and protrudes to the opposite side of the resin member, the bead portion forming a wall portion of the cooling flow path.

3. 3. The heat exchanger for cooling according to claim 1, wherein a bottom surface of the cooling flow passage includes the concave curved surface that is continuous over the entire width of the flow passage.

4. 4. The heat exchanger for cooling according to claim 3, wherein the curvature of said concave curved surface is 0.5 or less.

5. 3. The heat exchanger for cooling according to claim 1, wherein a bottom surface of the cooling flow passage includes a plurality of the concave curved surfaces arranged in parallel in a width direction of the flow passage.

6. 6. The heat exchanger for cooling according to claim 5, wherein the curvature of the concave curved surface is 2.0 or less.

7. The metal plate is made of either an aluminum alloy or stainless steel, 3. A cooling heat exchanger as described in claim 1 or 2, wherein the thickness dimension of the resin member in the portion outside the groove is less than 2.6 times the thickness dimension of the metal plate when the metal plate is made of an aluminum alloy, and is less than 8.8 times the thickness dimension of the metal plate when the metal plate is made of stainless steel.

8. 8. A cooling heat exchanger as described in claim 7, wherein the plate thickness dimension of the resin member in the portion outside the groove is within a range of 1.0 to 2.5 times the plate thickness dimension of the metal plate when the metal plate is made of an aluminum alloy, and within a range of 3.5 to 8.7 times the plate thickness dimension of the metal plate when the metal plate is made of stainless steel.

9. 3. A cooling heat exchanger as described in claim 1 or 2, wherein the minimum thickness dimension of the bottom wall portion of the groove is within a range of 0.3 times or more and 1.0 times or less the plate thickness dimension of the resin member in the portion outside the groove.

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