Heat exchanger for cooling

Abstract

To provide a heat exchanger for cooling of a new structure with which it is possible to realize stable cooling performance over a wider range on a cooling surface in contact with the object to be cooled.SOLUTION: Provided is a heat exchanger 10 for cooling in which a heat medium for cooling flows in a cooling flow path 38 formed in the inside and the object B to be cooled that is stacked together on the surface is cooled thereby. The cooling flow path 38 includes a supply flow path 40 in which the heat medium is supplied from the upstream side and a discharge flow path 42 in which the heat medium is discharged from the downstream side. The cooling flow path 38 is provided with a plurality of branch flow paths 44a-44h connecting the supply flow path 40 and the discharge flow path 42 that are branched from a plurality of points in the flow path length direction of the supply flow path 40. Resistance adjustment units 46a-46h for adjusting the flow resistance of the heat medium are disposed partially in the plurality of branch flow paths 44a-44h, and the flow resistance of the heat medium in the resistance adjustment units 46 is progressively smaller in a branch flow path 44 that branches off on the downstream side of the supply flow path 40.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a cooling heat exchanger used for cooling a cooling target such as a battery pack in an electrified vehicle such as an electric vehicle.

Background Art

[0002] In electrified vehicles such as electric vehicles and hybrid vehicles, cooling targets such as battery packs and electronic devices generate a large amount of heat due to miniaturization and high performance, and the importance of cooling performance is increasing. Conventionally, for example, as disclosed in International Publication No. 2019 / 008000 (Patent Document 1), a cooling heat exchanger having a structure in which cooling channels are formed between mutually overlapping plates has been adopted. In this cooling heat exchanger, one plate is overlapped with a cooling target such as a battery pack, and the cooling target is cooled by cooling the one plate with a refrigerant flowing through the cooling channel.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the cooling heat exchanger of Patent Document 1, the cooling channel has a structure in which a supply channel located on the upstream side for supplying a heat medium and a discharge channel located on the downstream side for discharging the heat medium are connected by a plurality of branch channels provided in parallel. The plurality of branch channels have substantially the same shape and size as each other.

[0005] However, in the structure of Patent Document 1 as described above, a difference in flow rate due to pressure loss or the like is likely to occur between the branch flow path that branches on the upstream side of the supply flow path and the branch flow path that branches on the downstream side of the supply flow path, and variations in cooling efficiency are likely to occur.

[0006] The problem to be solved by the present invention is to provide a heat exchanger for cooling having a novel structure that can achieve stable cooling performance over a wider range on the cooling surface in contact with the object to be cooled.

Means for Solving the Problem

[0007] Hereinafter, preferred embodiments for understanding the present invention will be described. However, each of the embodiments described below is described by way of example, and not only can they be adopted in appropriate combinations with each other, but also with respect to the plurality of components described in each embodiment, they can be recognized and adopted as independently as possible, and can also be adopted in combination with any of the components described in other embodiments as appropriate. Thereby, in the present invention, various other embodiments can be realized without being limited to the embodiments described below.

[0008] A first aspect is a heat exchanger for cooling that cools an object to be cooled superposed on a surface by a heat medium for cooling flowing through a cooling flow path formed inside. The cooling flow path includes a supply flow path through which the heat medium is supplied from the upstream side and a discharge flow path through which the heat medium is discharged from the downstream side. A plurality of branch flow paths connecting the supply flow path and the discharge flow path are provided in parallel, branching from the supply flow path at a plurality of locations in the flow path length direction of the supply flow path. Each of the plurality of branch flow paths is partially provided with a resistance adjustment portion for adjusting the flow resistance of the heat medium, and the flow resistance of the heat medium in the resistance adjustment portion is made smaller for the branch flow path that branches on the more downstream side of the supply flow path.

[0009] According to the cooling heat exchanger structured according to this aspect, the difference in the flow rate of the heat medium in the plurality of branch flow paths is reduced, and the variation in the cooling efficiency for each of these branch flow paths can be suppressed. Therefore, stable cooling performance by the plurality of branch flow paths can be realized over a wider cooling region. Further, since the resistance adjustment section is partially provided in the branch flow path, the branch flow path can be designed with a high degree of freedom in the portion where the resistance adjustment section is removed.

[0010] A second aspect is the cooling heat exchanger described in the first aspect, wherein at least one of the branch flow paths extends in a planar double spiral shape from the center toward the outer periphery, and both end portions located at the outer periphery are connected to each of the supply flow path and the discharge flow path.

[0011] According to the cooling heat exchanger structured according to this aspect, in the planar double spiral-shaped branch flow path, the upstream portion through which the low-temperature heat medium flows and the downstream portion through which the high-temperature heat medium flows are alternately arranged adjacent to each other. Therefore, heat exchange occurs between adjacent flow paths, and the temperature difference between the upstream portion and the downstream portion in the branch flow path is reduced. As a result, the change in the cooling efficiency in the length direction of the branch flow path is suppressed, and stable cooling performance can be realized over a wide range.

[0012] Further, since the branch flow path is in a spiral shape that curves or bends in the circumferential direction, the heat medium flowing in the flow path is more easily agitated compared to a linear branch flow path, and the temperature difference in the flow path cross section can be suppressed.

[0013] A third aspect is the cooling heat exchanger described in the first or second aspect, wherein the plurality of branch flow paths have the same flow path width dimensions in the portion where the resistance adjustment section is removed.

[0014] According to the cooling heat exchanger structured according to this aspect, by providing a partial orifice flow path portion in the branch flow path, it is possible to adjust the flow rates of the plurality of branch flow paths without making the flow path width dimensions of the portions of the plurality of branch flow paths outside the orifice flow path portion different from each other, thereby achieving stabilization of the cooling performance. Therefore, in the portions of the plurality of branch flow paths outside the orifice flow path portion, for example, the range of the cooling surface cooled by each branch flow path and the like are made uniform, and further stabilization of the cooling performance is achieved.

[0015] A fourth aspect is the cooling heat exchanger described in the third aspect, in which the plurality of branch flow paths have the same cross-sectional area of the flow path in the portion outside the resistance adjustment portion.

[0016] According to the cooling heat exchanger structured according to this aspect, in the portions of the plurality of branch flow paths outside the orifice flow path portion, since the cross-sectional areas of the flow paths are the same, the flow rate and the flow velocity are made uniform, and the variation in the cooling performance between the branch flow paths is further reduced.

[0017] A fifth aspect is the cooling heat exchanger described in any one of the first to fourth aspects, in which the cross-sectional area of the flow path of the branch flow path that branches on the more downstream side of the supply flow path is made larger toward the resistance adjustment portion of the branch flow path.

[0018] According to the cooling heat exchanger structured according to this aspect, the flow resistance at the orifice flow path portions in the plurality of branch flow paths can be easily set according to the cross-sectional area of the orifice flow path portion.

[0019] A sixth aspect is the cooling heat exchanger described in any one of the first to fifth aspects, in which the resistance adjustment portion is provided at the end of the branch flow path.

[0020] According to the cooling heat exchanger structured according to this aspect, since the orifice flow path portion is provided at the end of the branch flow path, in the middle portion of the branch flow path that performs heat exchange with the cooling surface that is superposed on the object to be cooled, the flow path cross-sectional area is ensured without being reduced by the orifice flow path portion, and a decrease in cooling efficiency is prevented.

[0021] A seventh aspect is the cooling heat exchanger according to any one of the first to sixth aspects, in which a flow path member having concave grooves formed on its surface and a cooling surface constituting member superposed on the object to be cooled are superposed on each other, and the concave grooves of the flow path member are covered by the cooling surface constituting member, and the cooling flow path is formed between the superposed surfaces of the flow path member and the cooling surface constituting member.

[0022] According to the cooling heat exchanger structured according to this aspect, since it has a laminated structure in which the flow path forming member and the cooling surface constituting member are superposed, by covering the opening of the concave groove formed in the flow path forming member with the cooling surface constituting member, the cooling flow path can be easily formed between the superposed surfaces of the flow path forming member and the cooling surface constituting member.

[0023] An eighth aspect is the cooling heat exchanger according to the seventh aspect, in which the flow path member is made of synthetic resin and the cooling surface constituting member is made of metal.

[0024] According to the cooling heat exchanger structured according to this aspect, by making the flow path forming member in which the concave grooves constituting the cooling flow path are formed of synthetic resin, the formation of the concave grooves becomes easy, and the degree of freedom in shape and the dimensional accuracy can also be improved. Further, since the cooling surface constituting member that constitutes the cooling surface superposed on the object to be cooled is made of metal, it becomes easy to form with a material having excellent heat transfer rate, and the efficiency of heat exchange via the cooling surface constituting member between the object to be cooled and the heat medium is improved. Further, since the cooling surface constituting member in contact with the object to be cooled is made of metal, it is easy to ensure the durability of the contact surface with the object to be cooled. Further, since the flow path member is made of synthetic resin, it is easy to achieve weight reduction compared to metal.

Effects of the Invention

[0025] According to the present invention, in a cooling heat exchanger, it is possible to achieve more stable cooling performance on a cooling surface in contact with an object to be cooled.

Brief Description of the Drawings

[0026]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0027] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0028] FIG. 1 shows a cooling heat exchanger 10 as a first embodiment of the present invention. The cooling heat exchanger 10 cools a battery pack B (described later) as an object to be cooled that is superimposed on its surface by heat exchange with a heat medium. As shown in FIG. 2, the cooling heat exchanger 10 has a laminated structure in which a resin plate 12 as a flow path member and a cooling plate 14 as a cooling surface constituent member are superimposed on each other. In the following description, the front-rear direction refers to the vertical direction in FIG. 3 (described later), the left-right direction refers to the left-right direction in FIG. 3, and the up-down direction refers to the left-right direction in FIG. 4 (described later) which is the superimposing direction of the resin plate 12 and the cooling plate 14.

[0029] As shown in Fig. 2, the resin plate 12 is generally rectangular plate-shaped as a whole, and is longer in the front-rear direction than in the left-right direction. The resin plate 12 is made of synthetic resin, and is preferably formed of a thermoplastic synthetic resin material. As the forming material of the resin plate 12, for example, polyamide, polyester, fluororesin, polyolefin, etc. can be preferably adopted. The resin plate 12 can also be formed of fiber-reinforced synthetic resin reinforced with glass fiber, carbon fiber, etc.

[0030] As shown in Figs. 3 to 6, the resin plate 12 is provided with a concave groove 16 opening on the upper surface. The concave groove 16 includes vertical groove portions 18a and 18b linearly extending in the front-rear direction at both left and right ends, and a plurality of horizontal groove portions 20 communicating the vertical groove portions 18a and 18b with each other. In Fig. 3 showing a top view of the cooling heat exchanger 10, the upper surface of the resin plate 12 is shown in a state of seeing through the cooling plate 14.

[0031] The horizontal groove portion 20 extends in a planar double spiral shape from the central portion toward the outer periphery. More specifically, the horizontal groove portion 20 includes a first straight portion 22 linearly extending from the center in the left-right direction, U-shaped first folded-back portions 24 and 24 extending from the left and right extending ends of the first straight portion 22 toward one of the front and rear and folding back by 180°, second straight portions 26 and 26 linearly extending from the first folded-back portions 24 and 24 in the left-right direction, substantially U-shaped second folded-back portions 28 and 28 extending from the left and right extending ends of the second straight portions 26 and 26 toward the other of the front and rear and folding back by 180°, and third straight portions 30 and 30 linearly extending from the second folded-back portions 28 and 28 in the left-right direction. And at the left and right extending ends of the third straight portions 30 and 30, the horizontal groove portion 20 is connected to the vertical groove portion 18.

[0032] In this embodiment, eight lateral groove portions 20a to 20h are arranged in parallel while being spaced apart from each other in the front-rear direction. The eight lateral groove portions 20a to 20h are substantially the same in shape and size as each other. Between adjacent lateral groove portions 20, 20 in the front-rear direction in the resin plate 12 and on the front and rear outer sides of the lateral groove portions 20a, 20h located at both front and rear ends, relief holes 32 penetrating in the vertical direction are respectively formed. The shape and size of the relief holes 32 are not particularly limited, but in this embodiment, they are substantially rectangular shapes that are longer in the left-right direction than in the front-rear direction. In this embodiment, the four front lateral groove portions 20a to 20d and the four rear lateral groove portions 20e to 20h are shaped such that they are inverted from each other in the front-rear direction.

[0033] Note that in this embodiment, in the formation portion of the concave groove 16, the resin plate 12 protrudes downward more than other portions, and the depth of the concave groove 16 is ensured. Therefore, in the resin plate 12, both left and right end portions that are the formation portions of the vertical groove portions 18a, 18b protrude downward, and the left and right middle portions protrude downward in the formation portion of each lateral groove portion 20.

[0034] The cooling plate 14 constitutes a cooling surface that is overlapped with a battery pack B (described later). The cooling plate 14 of this embodiment is in a substantially rectangular plate shape. The cooling plate 14 is made of metal. It is desirable that the cooling plate 14 is formed of a metal material having a high thermal conductivity, and for example, it is formed of aluminum, copper, stainless steel, or an alloy thereof.

[0035] As shown in FIG. 2, a supply port 34 and a discharge port 36 are provided at the front corner portion of the cooling plate 14. The supply port 34 has a substantially cylindrical shape protruding upward, and a central hole penetrates the cooling plate 14 in the vertical direction. Similarly, the discharge port 36 has a substantially cylindrical shape protruding upward, and a central hole penetrates the cooling plate 14 in the vertical direction. The supply port 34 and the discharge port 36 may be integrally provided on the cooling plate 14, or for example, they may be formed separately from the cooling plate 14 and fixed by means such as welding or adhesion.

[0036] As shown in FIGS. 2 and 4 to 6, the cooling plate 14 is superposed on the resin plate 12 from above. The resin plate 12 and the cooling plate 14 superposed on each other are fixed to each other by means such as adhesion using an adhesive, friction stir welding, laser welding, etc.

[0037] The concave groove 16 opening on the upper surface of the resin plate 12 is liquid-tightly covered by the cooling plate 14. And the cooling channel 38 is formed by the concave groove 16 covered by the cooling plate 14 at the opening. The cooling channel 38 is formed between the superposed surfaces of the resin plate 12 and the cooling plate 14. Therefore, the cooling channel 38 is provided inside the cooling heat exchanger 10. A part (the upper wall part) of the wall part of the cooling channel 38 is constituted by the cooling plate 14. Thus, by making the cooling heat exchanger 10 have a laminated structure in which the resin plate 12 and the cooling plate 14 are superposed, the cooling channel 38 extending inside the cooling heat exchanger 10 can be easily formed.

[0038] The part constituted by the right vertical groove part 18a in the cooling channel 38 is the supply channel 40. Also, the part constituted by the left vertical groove part 18b in the cooling channel 38 is the discharge channel 42. The supply channel 40 linearly extends in the front-rear direction at the right end part of the cooling heat exchanger 10 and is connected to the supply port 34 at the front end part. The discharge channel 42 linearly extends in the front-rear direction at the left end part of the cooling heat exchanger 10 and is connected to the discharge port 36 at the front end part.

[0039] The portion formed by the lateral groove portions 20a to 20h in the cooling flow path 38 is the branch flow paths 44a to 44h. As can be understood from the description of the lateral groove portion 20, the branch flow paths 44 extend in a planar double spiral shape, and both end portions located on the outer periphery are connected to one of the supply flow path 40 and the discharge flow path 42. The branch flow paths 44a to 44h branch at a plurality of locations in the flow path length direction of the supply flow path 40 and are provided in parallel with each other. Further, the plurality of branch flow paths 44a to 44h merge into the discharge flow path 42 at a plurality of locations in the front-rear direction at the downstream end portions. Therefore, the supply flow path 40 and the discharge flow path 42 are communicated with each other by the plurality of branch flow paths 44a to 44h.

[0040] Note that the branch flow path 44a located at the most front side among the branch flow paths 44a to 44h is connected to the supply flow path 40 at the most upstream side and is connected to the discharge flow path 42 at the most downstream side. On the other hand, the branch flow path 44h located at the most rear side among the branch flow paths 44a to 44h is connected to the supply flow path 40 at the most downstream side and is connected to the discharge flow path 42 at the most upstream side. In short, among the branch flow paths 44a to 44h, the ones located more frontally are connected to the supply flow path 40 at the upstream side and are connected to the discharge flow path 42 at the downstream side.

[0041] Then, the heat medium flowing in from an external flow path (not shown) through the supply port 34 flows through the supply flow path 40 from the front to the rear, flows into the discharge flow path 42 through the branch flow paths 44a to 44h, and then flows through the discharge flow path 42 from the rear to the front and is discharged from the discharge port 36 to the external flow path. Note that the flow direction of the heat medium in the supply flow path 40 and the discharge flow path 42 is indicated by arrows in FIG. 3. Further, a pump for flowing the heat medium and a refrigerator for cooling the high-temperature heat medium to a low-temperature heat medium are connected to the external flow path (not shown).

[0042] In this embodiment, the heat medium supplied through the supply port 34 provided at the front end, which is the upstream end of the supply channel 40, flows through the supply channel 40 from the front to the rear, and the heat medium that has flowed through the discharge channel 42 from the rear to the front is discharged to the outside through the discharge port 36 provided at the front end, which is the downstream end of the discharge channel 42. In this way, since both the supply port 34 and the discharge port 36 connected to the external channel are provided at the front end, the connection of the external channel is easy and the path of the external channel can be shortened.

[0043] The cooling heat exchanger 10 having such a structure has the battery pack B to be cooled stacked on the upper surface of the cooling plate 14 as shown in FIGS. 3 and 4. In this embodiment, one battery pack B is arranged for each part constituting the wall portion of each of the branch channels 44a to 44h in the cooling plate 14, and eight battery packs B, B, ···, B are arranged side by side with a space therebetween in the front-rear direction. Then, by the heat medium flowing through the cooling channel 38, heat exchange is performed through the cooling plate 14 between the low-temperature heat medium and the battery pack B that becomes high-temperature due to heat generation during use, so that the battery pack B is cooled.

[0044] The high-temperature heat medium whose temperature has risen due to heat exchange with the battery pack B is cooled by a refrigerator (not shown) connected to the external channel. Then, the heat medium cooled to a low temperature by the refrigerator is supplied from the supply port 34 to the cooling channel 38. Note that it is sufficient if a mechanism for lowering the temperature of the high-temperature heat medium is provided in the external channel. For example, an air-cooling device or a liquid-cooling device such as a radiator can be provided instead of the refrigerator.

[0045] Since the low-temperature heat medium is supplied from the external flow path to the supply flow path 40 and the high-temperature heat medium is discharged from the discharge flow path 42 to the external flow path, the heat medium flowing through the branch flow path 44 is likely to be at a low temperature in the portion near the connection end to the supply flow path 40 and is likely to be at a high temperature in the portion near the connection end to the discharge flow path 42. Since the branch flow path 44 of the present embodiment extends in a planar double spiral shape, the portions where the low-temperature heat medium flows and the portions where the high-temperature heat medium flows are arranged alternately in the radial direction. Therefore, in the branch flow path 44, heat exchange due to the temperature difference is likely to occur between the adjacent portions where the low-temperature heat medium flows and the portions where the high-temperature heat medium flows, and the temperature difference for each portion is reduced. As a result, the battery pack B superimposed on the wall portion of the branch flow path 44 is cooled more evenly throughout.

[0046] Incidentally, orifice flow path portions 46a to 46h as resistance adjustment portions for adjusting the flow rate of the heat medium are provided in the plurality of branch flow paths 44a to 44h. The orifice flow path portion 46 is partially provided in the flow path length direction of the branch flow path 44. As shown in FIG. 3, the orifice flow path portion 46 is provided at the end portion on the downstream side (discharge flow path 42 side) in the branch flow path 44.

[0047] The flow resistance of the heat medium flowing through the orifice flow path portion 46 is adjusted. In the present embodiment, the flow resistance of the heat medium is adjusted by the flow path cross-sectional area. More specifically, the flow path cross-sectional areas of the orifice flow path portions 46a to 46g are smaller than those of the other portions of the branch flow path 44, and the flow resistance is set larger than that of the other portions of the branch flow path 44. The flow path cross-sectional area of the orifice flow path portion 46h is the same as that of the other portions of the branch flow path 44, and the flow resistance of the heat medium is adjusted to be substantially the same as that of the other portions of the branch flow path 44. The orifice flow path portions 46a to 46g have both the flow path width dimension and the flow path depth dimension smaller than those of the other portions of the branch flow path 44. The other portions of the branch flow paths 44a to 44h excluding the orifice flow path portions 46a to 46h have the flow path width dimension and the flow path depth dimension substantially the same as each other. Therefore, the flow path cross-sectional areas of the other portions of the branch flow paths 44a to 44h excluding the orifice flow path portions 46a to 46h are substantially the same as each other.

[0048] The orifice flow path portions 46a to 46h are set to have different flow resistances from each other. That is, the flow resistance of the orifice flow path portion 46a is made larger than the flow resistance of the orifice flow path portion 46b. The flow resistance of the orifice flow path portion 46b is made larger than the flow resistance of the orifice flow path portion 46c. The flow resistance of the orifice flow path portion 46c is made larger than the flow resistance of the orifice flow path portion 46d. The flow resistance of the orifice flow path portion 46d is made larger than the flow resistance of the orifice flow path portion 46e. The flow resistance of the orifice flow path portion 46e is made larger than the flow resistance of the orifice flow path portion 46f. The flow resistance of the orifice flow path portion 46f is made larger than the flow resistance of the orifice flow path portion 46g. The flow resistance of the orifice flow path portion 46g is made larger than the flow resistance of the orifice flow path portion 46h. Thus, the flow resistance of the heat medium in the orifice flow path portions 46a to 46h is made smaller as the orifice flow path portion 46 provided in the branch flow path 44 that branches on the downstream side of the supply flow path 40 is closer.

[0049] In the present embodiment, as shown in FIG. 5, the flow path cross-sectional area is made larger as the orifice flow path portion 46 provided in the branch flow path 44 that branches on the downstream side of the supply flow path 40 is closer. In short, the flow path cross-sectional areas S(a) to S(h) of the orifice flow path portions 46a to 46h are set such that S(a) < S(b) < S(c) < S(d) < S(e) < S(f) < S(g) < S(h). Further, S(h) is made substantially the same as the flow path cross-sectional area of the portion of the branch flow path 44 excluding the orifice flow path portion 46. The flow resistance of the orifice flow path portions 46a to 46h becomes smaller as the flow path cross-sectional area is larger, provided that other conditions are the same. Therefore, by setting the flow path cross-sectional areas of the orifice flow path portions 46a to 46h as described above, the flow resistance is made smaller as the orifice flow path portion 46 provided in the branch flow path 44 that branches on the more downstream side of the supply flow path 40 is closer. The orifice flow path portions 46a to 46h of the present embodiment are configured by wall portions having a substantially semicircular cross-sectional shape, the outer diameter dimension in the cross-section is made substantially constant, and different flow path cross-sectional areas are set due to differences in the thickness of the wall portions.

[0050] The lengths of the orifice flow path portions 46a to 46h are substantially constant in this embodiment, but they may be different from each other. For example, by making the lengths of the orifice flow path portions 46a to 46h shorter than those of the orifice flow path portions 46 in the branch flow paths 44 that branch off on the downstream side of the supply flow path 40, the flow resistance of the orifice flow path portions 46 provided in the branch flow paths 44 that branch off on the more downstream side of the supply flow path 40 can be reduced, and tuning can also be performed with the lengths of the orifice flow path portions 46. Note that the frictional resistance acting between the wall surfaces of the orifice flow path portions 46a to 46h and the heat medium is substantially the same because the wall portions of the orifice flow path portions 46a to 46h are all composed of the resin plate 12 and the cooling plate 14.

[0051] The flow resistance of the orifice flow path portions 46a to 46h is set in consideration of differences in pressure loss due to differences in the branching positions of the branch flow paths 44a to 44h from the supply flow path 40, and the like. That is, the greater the pressure loss in the path where the branch flow path 44 branches off on the downstream side of the supply flow path 40, the smaller the flow rate for the same flow resistance. Therefore, by setting the flow resistance of the orifice flow path portion 46 to be smaller in the branch flow path 44 that branches off on the more downstream side of the supply flow path 40, the difference in the flow rates of the branch flow paths 44a to 44h is reduced. The flow resistance of the orifice flow path portions 46a to 46h is preferably adjusted so that the flow rates of the branch flow paths 44a to 44h are substantially constant.

[0052] In this way, since the difference in the flow rates of the branch flow paths 44a to 44h is reduced, it is difficult for a difference to occur in the performance of cooling the cooling plate 14 in the branch flow paths 44a to 44h, and the cooling performance is stabilized over a wider range of the cooling plate 14. Therefore, each battery pack B superimposed on the wall portion constituent parts of the branch flow paths 44a to 44h in the cooling plate 14 can be stably cooled.

[0053] Since the orifice channel portions 46a to 46h are partially provided in the branch channel 44, the flow channel cross-sectional area and thus the channel width of the branch channel 44 are ensured at the portions where the orifice channel portions 46 are removed. Therefore, while efficiently securing the cooling area by the branch channel 44 in the cooling plate 14 and effectively obtaining the cooling performance, the flow rate of the branch channel 44 can be adjusted by the orifice channel portions 46, and the cooling performance can be stabilized over a wide range. In the present embodiment, since the orifice channel portions 46 are provided at positions outside the battery pack B in the vertical projection, the orifice channel portions 46 with a small flow channel cross-sectional area and a narrow channel width are less likely to affect the cooling performance. Further, since the orifice channel portions 46 are arranged at the downstream ends of the branch channel 44, destabilization of the flow velocity distribution of the heat medium and flow turbulence caused by passing through the orifice channel portions 46 in the branch channel 44 are prevented, and it becomes easier to control the flow of the heat medium over the entire branch channel 44. Therefore, stabilization of the cooling performance can be expected. Further, in the present embodiment, since the channel width dimensions of the branch channels 44a to 44h are substantially constant and the flow channel cross-sectional areas are substantially constant, variations in the cooling performance of the branch channels 44a to 44h are more likely to be reduced.

[0054] The flow resistance of the orifice channel portions 46a to 46h is adjusted according to the size of the flow channel cross-sectional area. Particularly in the present embodiment, since the channel lengths of the orifice channel portions 46a to 46h are substantially constant and the orifice channel portions 46a to 46h are formed of the same member, the flow resistance of the orifice channel portions 46a to 46h is hardly affected by factors other than the flow channel cross-sectional area. Therefore, the magnitude relationship of the flow resistance of the orifice channel portions 46a to 46h can be easily set according to the difference in the flow channel cross-sectional areas of the orifice channel portions 46a to 46h.

[0055] As described above, the embodiments of the present invention have been described in detail, but the present invention is not limited by the specific description. For example, the shapes of the supply channel and the discharge channel are not limited to those extending linearly. Further, the supply channel and the discharge channel do not necessarily need to extend in the front-rear direction, nor do they need to extend parallel to each other.

[0056] The branched flow path preferably has a shape extending in a planar double spiral, but for example, it may extend linearly, may be in a spiral shape extending in a planar single spiral, or may extend in a curved or bent shape such as a wave shape or a meandering shape (including a linear zigzag). Further, when a branched flow path having a shape extending in a planar spiral is adopted, in the above-described embodiment, since the object to be cooled is a rectangular battery pack, the planar shape of the entire branched flow path 44 is made rectangular as shown in FIG. 3, thereby improving the cooling efficiency. However, the outer shape of the double spiral-shaped branched flow path in plan view is not particularly limited and may be, for example, a circular shape or the like.

[0057] The plurality of branched flow paths preferably have substantially the same shape and size as each other, but for example, at least one branched flow path may have a different shape and size from the other branched flow paths.

[0058] The number of the branched flow paths is not particularly limited as long as there are a plurality of them, and is appropriately designed according to the size and shape of the heat exchanger for cooling and the like. Also, the arrangement of the plurality of branched flow paths is not particularly limited.

[0059] The orifice flow path portion 46 may be provided in the middle of the flow path length direction of the branched flow path 44, but is preferably provided at the end of the branched flow path 44, whereby the difference in the flow of the heat medium between the upstream side and the downstream side with respect to the orifice flow path portion 46 and the change in the flow velocity at the formed portion of the orifice flow path portion 46 can be prevented from affecting the cooling performance. If the orifice flow path portion 46 is provided at the upstream end of the branched flow path 44, the heat medium in the branched flow path 44 is agitated on the downstream side of the orifice flow path portion 46, and an improvement in cooling efficiency can be expected.

[0060] The flow resistance of the resistance adjustment section can be adjusted based on the cross-sectional area of the flow path like the orifice flow path section 46 exemplified in the above embodiment. Additionally, for example, it is also possible to adjust by providing unevenness (including unevenness in a wavy shape) or a low-friction coating layer on the inner surface of the flow path of the resistance adjustment section. Further, for example, in the resistance adjustment sections in a plurality of branch flow paths, by making the cross-sectional area of the flow path and the unevenness on the inner surface of the flow path different from other parts of the branch flow path substantially the same and making the flow path lengths different, the flow resistances can be made different from each other. Also, by combining a plurality of elements that affect the flow resistance such as the cross-sectional area of the flow path and the unevenness on the inner surface of the flow path of the resistance adjustment section, the flow resistance of the resistance adjustment section may be adjusted. Note that in the resistance adjustment section, in at least the branch flow path that branches at the most upstream side of the supply flow path, it is desirable to increase the flow resistance by an orifice passage or the like to impart a predetermined flow resistance.

[0061] In the above embodiment, the resin plate 12 made of synthetic resin was exemplified as the flow path member, but the flow path member may be made of metal, which makes it easier to realize thinning of the cooling heat exchanger. Also, by making both the flow path member and the cooling surface constituting member made of synthetic resin, it is possible to further reduce the weight of the cooling heat exchanger. In this case, it is desirable to employ, as at least the forming material of the cooling surface constituting member, for example, a thermally conductive synthetic resin in which a thermally conductive filler made of metal powder or powdery carbon having a high thermal conductivity is mixed with the synthetic resin material.

[0062] Also, in the cooling heat exchanger, for example, concave grooves may be formed on both surfaces of the flow path member, and cooling plates may be stacked on both surfaces of the flow path member, respectively, so that cooling surfaces to be superposed on the object to be cooled are set on both surfaces. Also, a plurality of cooling surfaces extending in directions intersecting each other may be set in one cooling heat exchanger. Note that, for example, by making the flow path member made of metal, at least one of the cooling surfaces superposed on the object to be cooled can also be constituted by the flow path member.

[0063] In the above-described embodiment, the cooling heat exchanger 10 having a laminated structure in which the resin plate 12 and the cooling plate 14 are laminated was shown. However, the cooling heat exchanger is not limited to the laminated structure. For example, a structure in which a pipe constituting a cooling flow path is partially exposed on the surface of a block-shaped or plate-shaped member, and the exposed portion of the pipe constitutes a cooling surface may also be adopted in the cooling heat exchanger.

[0064] The object to be cooled is not limited to the battery pack B exemplified in the above-described embodiment, and may be, for example, a control device including an electronic circuit or the like as a heat generating body.

Explanation of Reference Numerals

[0065] 10 Cooling heat exchanger (first embodiment) 12 Resin plate (flow path member) 14 Cooling plate (cooling surface constituting member) 16 Concave groove 18 Vertical groove portion 18a Vertical groove portion 18b Vertical groove portion 20 Horizontal groove portion 20a Horizontal groove portion 20b Horizontal groove portion 20c Horizontal groove portion 20d Horizontal groove portion 20e Horizontal groove portion 20f Horizontal groove portion 20g Horizontal groove portion 20h Horizontal groove portion 22 First straight portion 24 First turning portion 26 Second straight portion 28 Second turning portion 30 Third straight portion 32 Relief hole 34 Supply port 36 Discharge port 38 Cooling flow path 40 Supply flow path 42 Discharge flow path 44 Branch flow path 44a Branch flow path 44b Branch flow path 44c branched flow path 44d branched flow path 44e branched flow path 44f branched flow path 44g branched flow path 44h branched flow path 46 orifice flow path section (resistance adjustment section) 46a orifice flow path section (resistance adjustment section) 46b orifice flow path section (resistance adjustment section) 46c orifice flow path section (resistance adjustment section) 46d orifice flow path section (resistance adjustment section) 46e orifice flow path section (resistance adjustment section) 46f orifice flow path section (resistance adjustment section) 46g orifice flow path section (resistance adjustment section) 46h orifice flow path section (resistance adjustment section) B battery pack

Claims

1. A cooling heat exchanger that cools a cooling target superimposed on a surface by allowing a heat transfer medium for cooling to flow through a cooling flow path formed inside, wherein the cooling flow path includes a supply flow path through which the heat transfer medium is supplied from an upstream side and a discharge flow path through which the heat transfer medium is discharged from a downstream side, and a plurality of branch flow paths connecting the supply flow path and the discharge flow path are branched from the supply flow path at a plurality of locations in the flow path length direction of the supply flow path and provided in parallel, and resistance adjusting portions for adjusting the flow resistance of the heat transfer medium are partially provided in the plurality of branch flow paths, respectively, wherein the flow resistance of the heat transfer medium in the resistance adjusting portion is made smaller for the branch flow paths that branch on the more downstream side of the supply flow path. A cooling heat exchanger.

2. At least one of the branch flow paths extends in a planar double spiral shape from the center toward the outer periphery, and both end portions located at the outer periphery are connected to one of the supply flow path and the discharge flow path. The cooling heat exchanger according to Claim 1.

3. The cooling heat exchanger according to Claim 1 or 2, wherein the flow path width dimensions of the plurality of branch flow paths in portions excluding the resistance adjusting portions are the same as each other.

4. The cooling heat exchanger according to Claim 3, wherein the flow path cross-sectional areas of the plurality of branch flow paths in portions excluding the resistance adjusting portions are the same as each other.

5. The cooling heat exchanger according to Claim 1 or 2, wherein the flow path cross-sectional area of the branch flow paths that branch on the more downstream side of the supply flow path is made larger for the resistance adjusting portions of the branch flow paths.

6. The cooling heat exchanger according to Claim 1 or 2, wherein the resistance adjusting portion is provided at an end portion of the branch flow path.

7. A flow path member having concave grooves formed on a surface and a cooling surface constituting member superimposed on the cooling target are superimposed on each other, and the concave grooves of the flow path member are covered by the cooling surface constituting member, and the cooling flow path is formed between the superimposing surfaces of the flow path member and the cooling surface constituting member. The cooling heat exchanger according to Claim 1 or 2.

8. The cooling heat exchanger according to Claim 7, wherein the flow path member is made of synthetic resin and the cooling surface constituting member is made of metal.

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