Heat exchanger and method for manufacturing the same

Abstract

To improve a cooling performance of a heat exchanger to a battery.SOLUTION: A heat exchanger that performs heat exchange with a battery mounted onto an electric motorcar comprises: a first plate member; a second plate member; and a bonding part. The first plate member faces the battery. The second plate member is arranged so as to face the first plate member at the side opposite the battery, and forms a flow channel in which a heat exchange medium passes at the space between the first and second plate members. The bonding part is a portion where the first and second plate members are bonded by welding, and includes a plurality of welding wires that are extended in a first direction, and segment the flow channel so as to be arranged in a second direction orthogonal to the first direction. In the plurality of welding wires, the welding wire positioned closer to the first plate member side than a neutral axis is a first welding wire, and the welding wire positioned closer to the second plate member side than the neutral axis is a second welding wire. A total value of the shortest distance up to the first welding wire from the neutral axis is almost the same as a total value of the shortest distance up to the second welding wire from the neutral axis.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to heat exchangers and methods for manufacturing heat exchangers. [Background technology]

[0002] Patent Document 1 discloses a heat exchanger for cooling a battery mounted on an electric vehicle by exchanging heat with the battery. The heat exchanger includes two plate-shaped members joined by laser beam welding and a flow path formed between the two plate-shaped members and through which a heat exchange medium passes. The flow path is defined by a plurality of joints at the joining points of the two plate-shaped members, the plurality of joints being aligned in an orthogonal direction perpendicular to the flow direction of the heat exchange medium. Patent Document 1 discloses a configuration in which a plurality of joints are arranged on a neutral axis extending in the orthogonal direction in a cross section of the heat exchanger taken along the orthogonal direction. Patent Document 1 also discloses a configuration in which a plate-shaped member facing the battery has a cooling surface that contacts the battery, the cooling surface extending in a plane parallel to the neutral axis of the heat exchanger, and a plurality of joints are arranged away from the neutral axis. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2020-510534 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when multiple joints are located on the neutral axis of the heat exchanger, the heat exchanger does not come into contact with the battery at the positions where the multiple joints are provided, which tends to reduce the cooling surface of the heat exchanger that comes into contact with the battery, resulting in a problem that the cooling performance of the heat exchanger for the battery is likely to deteriorate.

[0005] Furthermore, when multiple joints are arranged on the planar cooling surface of the heat exchanger away from the neutral axis, the cooling surface is easily deformed due to thermal distortion of the heat exchanger caused by contraction stress when the multiple joints cool, making it difficult for the cooling surface to come into contact with the battery, which can lead to a problem of reduced cooling performance of the heat exchanger for the battery.

[0006] One aspect of the present disclosure is directed to improving the cooling performance of a heat exchanger for a battery. [Means for solving the problem]

[0007] One aspect of the present disclosure is a heat exchanger that exchanges heat with a battery mounted on an electric vehicle, the heat exchanger including a first plate member, a second plate member, and a joint. The first plate member is a plate-shaped member configured to face the battery. The second plate member is a plate-shaped member arranged to face the first plate member on the side opposite the battery, and forms a flow path through which a heat exchange medium passes between the first plate member and the second plate member. The joint is a portion where the first plate member and the second plate member are joined by welding. The joint has a plurality of weld lines extending in a first direction and aligned in a second direction perpendicular to the first direction to define the flow path. The plurality of weld lines are respectively arranged on the first plate member side and the second plate member side with respect to a neutral axis extending in the second direction in a cross section of the heat exchanger perpendicular to the first direction. Of the plurality of weld lines, at least one weld line located closer to the first plate member than the neutral axis is defined as a first weld line, and at least one weld line located closer to the second plate member than the neutral axis is defined as a second weld line. The sum of the shortest distances from the neutral axis to each of the at least one first weld line is approximately the same as the sum of the shortest distances from the neutral axis to each of the at least one second weld line.

[0008] In this configuration, deformation of the heat exchanger caused by contraction stress when the first weld line cools is likely to be offset by deformation of the heat exchanger caused by contraction stress when the second weld line cools. This reduces the effects of thermal distortion on the heat exchanger having a joint formed by welding. In other words, deformation of the first plate member is suppressed, making it easier for the first plate member to come into contact with the battery. This improves the cooling performance of the heat exchanger for the battery.

[0009] In one aspect of the present disclosure, the number of the at least one first weld line and the number of the at least one second weld line may be the same, and the shortest distance from the neutral axis to each of the at least one first weld line and the shortest distance from the neutral axis to each of the at least one second weld line may be the same.

[0010] In this configuration, deformation of the heat exchanger caused by the first weld line is easily offset by deformation of the heat exchanger caused by the second weld line, which reduces the effects of thermal distortion of the heat exchanger having a joint formed by welding, thereby improving the cooling performance of the heat exchanger for the battery.

[0011] In one embodiment of the present disclosure, the plurality of weld lines may be arranged symmetrically with respect to a center line in a cross section of the heat exchanger perpendicular to the first direction. The center line may be a line that passes through the center of the heat exchanger in the second direction in the cross section of the heat exchanger perpendicular to the first direction and is perpendicular to the neutral axis.

[0012] With this configuration, the influence of thermal distortion of the heat exchanger can be suppressed at each of the locations on both sides of the center line.

[0013] In one aspect of the present disclosure, the first direction may be a longitudinal direction of the heat exchanger. Since the weld lines extending in the longitudinal direction of the heat exchanger contribute more to the thermal distortion of the heat exchanger than the weld lines extending in the lateral direction of the heat exchanger, the above-described configuration makes it easier to suppress the effects of the thermal distortion of the heat exchanger.

[0014] In one aspect of the present disclosure, the first plate member may have a contact portion that contacts the battery, is substantially parallel to the neutral axis, and extends substantially flat in the first and second directions. At least one first weld line may be disposed on the contact portion.

[0015] With this configuration, the area of ​​the contact portion where the flow path is provided and the area of ​​the first weld line come into contact with the battery, which increases the area of ​​the contact portion that comes into contact with the battery and exchanges heat with the battery, thereby further improving the cooling performance of the heat exchanger for the battery.

[0016] In one aspect of the present disclosure, the plurality of weld lines may be formed by heat input to the joint, and a sum of values ​​obtained by multiplying the shortest distance from the neutral axis to each of the at least one first weld line by the heat input amount at the time of forming each of the at least one first weld line may be approximately equal to a sum of values ​​obtained by multiplying the shortest distance from the neutral axis to each of the at least one second weld line by the heat input amount at the time of forming each of the at least one second weld line.

[0017] In this configuration, the evaluation of the effects of thermal distortion on the heat exchanger takes into account not only the shortest distance from the neutral axis to each weld line but also the amount of heat input when each weld line was formed. This makes it easier for deformations caused by the first weld line to be offset by deformations caused by the second weld line, even if the shrinkage stresses of the weld lines differ when they cool due to differences in the amount of heat input when each weld line is formed. This reduces the effects of thermal distortion even in heat exchangers with joints that are heated under different conditions during welding. This improves the cooling performance of the heat exchanger for the battery.

[0018] In one aspect of the present disclosure, a method for manufacturing a heat exchanger may include: arranging a second plate member over a first plate member so that the first plate member and the second plate member abut at a joint; and forming a plurality of weld lines by inputting heat into the joint to join the first plate member and the second plate member. A sum of values ​​obtained by multiplying the shortest distance from the neutral axis to each of the at least one first weld line by the amount of heat input when each of the at least one first weld line is formed may be approximately equal to a sum of values ​​obtained by multiplying the shortest distance from the neutral axis to each of the at least one second weld line by the amount of heat input when each of the at least one second weld line is formed.

[0019] In this configuration, the evaluation of the effects of thermal distortion on the heat exchanger takes into account not only the shortest distance from the neutral axis to each weld line but also the amount of heat input when each weld line was formed. This makes it easier for deformations caused by the first weld line to be offset by deformations caused by the second weld line, even if the shrinkage stresses of the weld lines differ when they cool due to differences in the amount of heat input when each weld line is formed. This reduces the effects of thermal distortion even in heat exchangers with joints that are heated under different conditions during welding. This improves the cooling performance of the heat exchanger for the battery. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 2 is a schematic perspective view showing a heat exchanger. [Figure 2] FIG. 2 is a side view schematically showing the arrangement of the heat exchanger relative to the battery. [Figure 3] FIG. 2 is an end view taken along the line III-III in FIG. [Figure 4] FIG. 2 is a schematic plan view showing a heat exchanger. [Figure 5] FIG. 10 is a schematic perspective view showing a heat exchanger of a first modified example. [Figure 6] FIG. 10 is a side view schematically showing the arrangement of a heat exchanger of a first modified example relative to a battery. [Figure 7]FIG. 10 is a schematic plan view showing a heat exchanger of a first modified example. [Figure 8] FIG. 10 is an end view in a cross section perpendicular to the longitudinal direction, schematically showing the configuration of one side of the center line of a heat exchanger of a second modified example. [Figure 9] FIG. 11 is an end view in a cross section perpendicular to the longitudinal direction, schematically showing the configuration of one side of the center line of a heat exchanger of a third modified example. [Figure 10] FIG. 2 is a diagram schematically illustrating a state in which a heat exchange device is arranged in correspondence with a battery pack. [Figure 11] FIG. 1 is a diagram schematically illustrating a heat exchange device in which a plurality of heat exchangers are connected together to form an integrated unit. [Figure 12] FIG. 10 is a diagram schematically showing the shape of a flow path of a heat exchanger according to a fourth modified example. [Figure 13] FIG. 10 is a diagram schematically illustrating the shape of a flow path in a heat exchanger according to a fifth modified example. [Figure 14] FIG. 2 is a flow chart showing a method for manufacturing a heat exchanger. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings. [1. Configuration] The heat exchanger 100 shown in FIG. 1 exchanges heat with a battery mounted on an electric vehicle to cool or heat the battery. An electric vehicle is a vehicle that runs using all or part of the electrical energy stored in a battery as its power source. Electric vehicles include electric vehicles, plug-in hybrid vehicles, hybrid vehicles, and fuel cell vehicles. The heat exchanger 100 is configured so that a heat exchange medium such as coolant flows inside. The heat exchanger 100 has an inlet 101 through which the heat exchange medium flows into the heat exchanger 100 and an outlet 102 through which the heat exchange medium is discharged from the heat exchanger 100.

[0022] In this embodiment, the inlet 101 and the outlet 102 are provided on a first plate member 1, which will be described later. Specifically, the inlet 101 is disposed at a first end S1 in the short side direction S of the heat exchanger 100, and is disposed at a first end L1 in the long side direction L of the heat exchanger 100. The outlet 102 is disposed at the first end S1 in the short side direction S of the heat exchanger 100, and is disposed at a second end L2 in the long side direction L of the heat exchanger 100. Note that the positions at which the inlet and the outlet are disposed in the heat exchanger may vary depending on the shape of the flow path through which the heat exchange medium flows.

[0023] As shown in FIG. 2, the heat exchanger 100 faces the contact surface 201 of the battery 200, and is disposed so that the battery 200 is located between the inlet 101 and the outlet 102. A thermally conductive material 300 is disposed between the heat exchanger 100 and the battery 200. Note that a thermally conductive material does not necessarily have to be disposed between the heat exchanger and the battery. A frame 400 is provided so as to surround a side surface of the battery 200 that extends perpendicular to the contact surface 201, and the heat exchanger 100 is located inside the frame 400. The surface of the heat exchanger 100 opposite to the surface facing the battery 200 is covered by a lower case 500. Note that, for convenience, a portion of the frame 400 is not shown in FIG. 2.

[0024] The heat exchanger 100 may have a longitudinal direction L corresponding to the front-to-rear direction of the electric vehicle and a lateral direction S corresponding to the left-to-right direction of the electric vehicle, or may have a longitudinal direction L corresponding to the left-to-right direction of the electric vehicle and a lateral direction S corresponding to the front-to-rear direction of the electric vehicle.

[0025] As shown in FIG. 3, in this embodiment, the heat exchanger 100 includes a first plate member 1, a second plate member 2, eight joints 3, and six flow paths 4. <First plate member 1> The first plate member 1 is a substantially rectangular plate member and faces the contact surface 201 of the battery 200. The first plate member 1 is made of a metal with high thermal conductivity, such as aluminum. The first plate member may also be made of a metal with high corrosion resistance, such as stainless steel. The first plate member 1 has two contact portions 11 and three non-contact portions 12.

[0026] The contact portion 11 is a portion of the first plate member 1 that comes into indirect or direct contact with the battery 200, and is generally parallel to a neutral axis N extending in the short direction S in a cross section (hereinafter simply referred to as a cross section) perpendicular to the longitudinal direction L of the heat exchanger 100, and extends in a generally planar shape in the longitudinal direction L and the short direction S. The neutral axis is the line where the cross section intersects with a neutral plane, which is a plane where neither compressive strain nor tensile strain occurs in an object. At the neutral axis, even if a bending moment acts on the object, the tensile force and compressive force balance each other, and no stress is generated in the cross section. The two contact portions 11 are located on the same plane and arranged side by side in the short direction S.

[0027] The non-contact portions 12 extend in the longitudinal direction L of the heat exchanger 100. The three non-contact portions 12 are located on the same plane and are arranged side by side in the lateral direction S. Of the three non-contact portions 12, one non-contact portion 12 is located at a first end S1 in the lateral direction S, one non-contact portion 12 is located at a second end S2 in the lateral direction S, and one non-contact portion 12 is located between the two contact portions 11. The two contact portions 11 protrude toward the side where the battery 200 is arranged (e.g., upward) relative to the three non-contact portions 12. In other words, a step is formed between each non-contact portion 12 and each contact portion 11. In this embodiment, the first plate member 1 has a plurality of through holes 13 in the non-contact portion 12 located between the two contact portions 11. The plurality of through holes 13 are arranged at intervals from each other in the longitudinal direction L. Note that the first plate member does not necessarily have to have a plurality of through holes in the non-contact portion located between the two contact portions.

[0028] <Second plate member> The second plate member 2 is a substantially rectangular plate member and is arranged to face the first plate member 1 on the opposite side to the battery 200. For example, if the contact surface 201 of the battery 200 mounted on the electric vehicle extends in a substantially horizontal direction, the second plate member 2 is arranged below or above the first plate member 1. Furthermore, if the contact surface 201 of the battery 200 mounted on the electric vehicle extends in a substantially vertical direction, the second plate member 2 is arranged to the left, right, front, or rear of the first plate member 1. Like the first plate member 1, the second plate member 2 is made of a metal with high thermal conductivity, such as aluminum. The second plate member may also be made of a metal with high corrosion resistance, such as stainless steel. The second plate member 2 has five flat plate portions 21 and four protruding portions 22.

[0029] The flat plate portions 21 are portions that do not abut against the contact portions 11 of the first plate member 1, and extend substantially parallel to the neutral axis N and in a substantially planar shape in the longitudinal direction L and the lateral direction S. The five flat plate portions 21 are located on the same plane and arranged side by side in the lateral direction S. Of the five flat plate portions 21, one flat plate portion 21 located at a first end S1 in the lateral direction S, one flat plate portion 21 located at a second end S2 in the lateral direction S, and one flat plate portion 21 located at the center of the second plate member 2 abut against the respective non-contact portions 12 of the first plate member 1 that face each flat plate portion 21. In this embodiment, the second plate member 2 has a plurality of through holes 23 in the flat plate portion 21 located at the center in the lateral direction S. The multiple through holes 23 are arranged at intervals from each other in the longitudinal direction L. Each of the through holes 23 of the second plate member 2 overlaps with each of the through holes 13 of the first plate member 1. The second plate member does not necessarily have to have a plurality of through holes in the flat plate portion located at the center in the short-side direction S.

[0030] The protruding portions 22 are portions that come into contact with the contact portions 11 of the first plate member 1, and extend in the longitudinal direction L of the heat exchanger 100. The four protruding portions 22 are arranged side by side in the lateral direction S, and are each located between two adjacent flat plate portions 21. The four protruding portions 22 protrude toward the first plate member 1 relative to the five flat plate portions 21. In other words, a step is formed between each protruding portion 22 and each flat plate portion 21.

[0031] <Joint part> The eight joints 3 are locations where the first plate member 1 and the second plate member 2 are joined by welding, and extend in the longitudinal direction L of the heat exchanger 100. For example, laser welding, arc welding, or the like is used for welding.

[0032] The joints 3 are provided at locations where the contact portions 11 of the first plate member 1 abut against the convex portions 22 of the second plate member 2, and where the non-contact portions 12 of the first plate member 1 abut against the flat plate portions 21 of the second plate member 2. The two contact portions 11 of the first plate member 1 and the five flat plate portions 21 of the second plate member 2 do not abut against each other but face each other with a gap between them. This forms six flow paths 4 between the first plate member 1 and the second plate member 2, through which the heat exchange medium passes.

[0033] As shown in FIGS. 3 and 4 , each joint 3 has a weld line. In this embodiment, the heat exchanger 100 has eight weld lines 31a to 31h. The eight weld lines 31a to 31h are parallel to the above-mentioned neutral plane along the neutral axis N, extend straight in the longitudinal direction L, and are aligned in the short direction S, dividing the space between the first plate member 1 and the second plate member 2 into the above-mentioned six flow paths 4. Some of the eight weld lines 31a to 31h are located on the first plate member 1 side with respect to the neutral axis N, and the rest are located on the second plate member 2 side. In the following description, of the eight weld lines 31a to 31h, the weld lines located closer to the first plate member 1 than the neutral axis N will be referred to as first weld lines 31b, 31c, 31f, and 31g, and the weld lines located closer to the second plate member 2 than the neutral axis N will be referred to as second weld lines 31a, 31d, 31e, and 31h.

[0034] The eight weld lines 31a to 31h are arranged symmetrically with respect to a center line A in the cross section of the heat exchanger 100. The center line A is a line that passes through the center of the cross section of the heat exchanger 100 in the short direction S and is perpendicular to the neutral axis N.

[0035] Specifically, first welding lines 31b and 31c are arranged in contact portion 11 on the first end S1 side of first plate member 1, and first welding lines 31f and 31g are arranged in contact portion 11 on the second end S2 side of first plate member 1. Second welding line 31a is arranged in non-contact portion 12 located at first end S1 of first plate member 1, and second welding line 31h is arranged in non-contact portion 12 located at second end S2 of first plate member 1. Second welding line 31d is arranged on the first end S1 side of through holes 13 and 23 in non-contact portion 12 located at the center in the short direction S of first plate member 1, and second welding line 31e is arranged on the second end S2 side of through holes 13 and 23 in non-contact portion 12.

[0036] Furthermore, the sum of the shortest distances LA1, LA2, LA3, and LA4 from the neutral axis N to each of the first welding lines 31b, 31c, 31f, and 31g is approximately the same as the sum of the shortest distances LB1, LB2, LB3, and LB4 from the neutral axis N to each of the second welding lines 31a, 31d, 31e, and 31h. In this embodiment, the number of first welding lines 31b, 31c, 31f, and 31g and the number of second welding lines 31a, 31d, 31e, and 31h are all four, and the shortest distances LA1, LA2, LA3, and LA4 and the shortest distances LB1, LB2, LB3, and LB4 are all the same, for example, 1.0 mm. That is, when the first welding lines 31b, 31c, 31f, 31g and the second welding lines 31a, 31d, 31e, 31h are equally spaced with respect to the neutral axis N as in this embodiment, (number of first welding lines × shortest distance from the neutral axis N to the first welding line) = (number of second welding lines × shortest distance from the neutral axis N to the second welding line).

[0037] The ends of each welding line 31a to 31h in the longitudinal direction L are also connected by a welding line extending in the short direction S so that six flow paths 4 are formed through which the heat exchange medium flows from the inlet 101 to the outlet 102 along the arrows shown in Figure 4.

[0038] <Heat exchanger manufacturing method> Next, a method for manufacturing the heat exchanger 100 will be described with reference to Fig. 14. The method for manufacturing the heat exchanger 100 includes a pressing step S10, an arrangement step S20, and a joining step S30.

[0039] (pressing process) First, a flat blank is pressed to form a first plate member 1 and a second plate member 2 each having a predetermined shape. Specifically, the first plate member 1 is press-formed to form two contact portions 11 and three non-contact portions 12. The second plate member 2 is press-formed to form five flat portions 21 and four protrusions 22.

[0040] (Placement process) Next, the second plate member 2 is placed on top of the first plate member 1 so that the first plate member 1 and the second plate member 2 abut at each joint 3 (see FIG. 3). Specifically, the first plate member 1 and the second plate member 2 are placed on top of each other so that at each joint 3, the two contact portions 11 abut against the four protrusions 22 and the three non-contact portions 12 abut against the three flat plate portions 21 facing them.

[0041] (Joining process) Next, eight weld lines 31a to 31h are formed by heat input to each joint 3, joining the first plate member 1 and the second plate member 2. Specifically, for example, a laser beam is irradiated onto each joint 3 along the longitudinal direction L. As a result, the eight weld lines 31a to 31h are formed such that the first weld lines 31b, 31c, 31f, and 31g and the second weld lines 31a, 31d, 31e, and 31h are arranged on both sides of the neutral axis N as described above (see FIG. 3). In this way, the heat exchanger 100 is obtained.

[0042] Each of the weld lines 31a-31h is formed by heat input from a laser beam or the like to each joint 3, causing melting into the first plate member 1 and the second plate member 2. In this embodiment, in the joining step S30, heat input to each joint 3 is performed under constant conditions. That is, the amount of heat input when forming each of the weld lines 31a-31h is approximately the same. The amount of heat input is calculated by (welding output ÷ welding speed × weld length).

[0043] [2.Effects] According to the embodiment described above in detail, the following effects can be obtained. (2a) In this embodiment, the first weld lines 31b, 31c, 31f, and 31g and the second weld lines 31a, 31d, 31e, and 31h are equally spaced with respect to the neutral axis N. This makes it easier to offset deformation of the heat exchanger 100 caused by contraction stress when the first weld lines 31b, 31c, 31f, and 31g cool, with deformation of the heat exchanger 100 caused by contraction stress when the second weld lines 31a, 31d, 31e, and 31h cool. This reduces the effects of thermal distortion on the heat exchanger 100, which has eight joints 3. That is, deformation of the first plate member 1 is reduced, making it easier for the two contact portions 11 of the first plate member 1 to indirectly or directly contact the battery 200. In other words, it makes it easier to maintain the surfaces of each contact portion 11 facing the battery 200 and exchanging heat with the battery 200 flat. This improves the cooling performance of the heat exchanger 100 for the battery 200. Furthermore, since deformation of the first plate member 1 is suppressed, the ease of assembling the heat exchanger 100 to the battery 200 also improves.

[0044] (2b) In the present embodiment, the first weld lines 31b and 31c are disposed at the contact portion 11 on the first end S1 side of the first plate member 1, and the first weld lines 31f and 31g are disposed at the contact portion 11 on the second end S2 side of the first plate member 1. As a result, the portion of each contact portion 11 where each flow path 4 is provided and the portion of each first weld line 31b, 31c, 31f, and 31g are provided are in indirect or direct contact with the battery 200. This makes it possible to ensure a large area for the surface of each contact portion 11 that is in indirect or direct contact with the battery 200 and that exchanges heat with the battery 200. This further improves the cooling performance of the heat exchanger 100 for the battery 200.

[0045] (2c) In this embodiment, the eight weld lines 31a to 31h are arranged symmetrically with respect to the center line A in the cross section of the heat exchanger 100. Therefore, the influence of thermal distortion of the heat exchanger 100 can be suppressed in each region on both sides of the center line A.

[0046] (2d) In this embodiment, the eight weld lines 31a to 31h extend in the longitudinal direction L of the heat exchanger 100. The weld lines extending in the longitudinal direction L of the heat exchanger 100 contribute more to the thermal distortion of the heat exchanger 100 than the weld lines extending in the lateral direction S of the heat exchanger 100. Therefore, according to the configuration of the heat exchanger 100 of this embodiment, it is easier to obtain the effect of suppressing the influence of the thermal distortion of the heat exchanger 100.

[0047] In this embodiment, the longitudinal direction L corresponds to an example of a first direction, and the lateral direction S corresponds to an example of a second direction.

[0048] 3. Other Embodiments Although the embodiments of the present disclosure have been described above, it goes without saying that the present disclosure is not limited to the above-described embodiments and can take on various forms.

[0049] (3a) In the above embodiment, the inlet 101 and outlet 102 for the heat exchange medium are disposed on the first plate member 1, but the arrangement of the inlet and outlet is not limited to this. For example, as shown in Figures 5 to 7, the inlet 101a and outlet 102a of the heat exchanger 100a of the first modified example may be provided at positions extending from the first end S1 in the short-side direction S of the first plate member 1a.

[0050] In this case, as shown in FIG. 6 , the heat exchanger 100a faces the contact surface 201 of the battery 200 and is disposed so that the battery 200 does not overlap the inlet 101a and the outlet 102a in the short-side direction S. A thermally conductive material 300 may or may not be disposed between the heat exchanger 100a and the battery 200. The frame 400 is disposed around the side of the battery 200, and the inlet 101a and the outlet 102a are located outside the frame 400. For convenience, part of the frame 400 is not illustrated in FIG. 6 . The heat exchanger 100a of the first modified example can also serve as a lower case. Therefore, unlike the heat exchanger 100 of the above embodiment, the surface of the heat exchanger 100a opposite to the surface facing the battery 200 does not need to be covered by the lower case.

[0051] (3b) In the above embodiment, the heat exchanger 100 is exemplified, in which six flow paths 4 are formed by eight joints 3 having first welding lines 31b, 31c, 31f, and 31g and second welding lines 31a, 31d, 31e, and 31h that are equally spaced with respect to the neutral axis N. However, the configuration of the heat exchanger is not limited to this, and the number of flow paths, i.e., the number of welding lines, is not limited.

[0052] For example, a heat exchanger 100b of a second modified example shown in Fig. 8 may have eight flow paths 4b formed by ten joints 3b. Specifically, the first plate member 1b may have two contact portions 11b and three non-contact portions 12b, and the second plate member 2b may have seven flat portions 21b and six protrusions 22b. For convenience, Fig. 8 illustrates only the configuration of a half portion (hereinafter referred to as the first portion) of the heat exchanger 100b on the first end S1 side, centered on the center line A. However, the cross section of the heat exchanger 100b is symmetrical with respect to the center line A.

[0053] In the first portion of the heat exchanger 100b, each joint 3b has a weld line. The first portion of the heat exchanger 100b has five weld lines 32a to 32e. The first weld lines 32b, 32c, and 32d are located in the contact portion 11b on the first end S1 side of the first plate member 1b. The second weld line 32a is located in the non-contact portion 12b on the first end S1 side of the first plate member 1b, and the second weld line 32e is located closer to the first end S1 side than the through holes 13 and 23 in the non-contact portion 12b located in the center of the first plate member 1b in the short direction S.

[0054] As a result, the portions of the contact portion 11b where the flow paths 4b are provided and the portions of the first welding lines 32b, 32c, 32d are provided are in indirect or direct contact with the battery 200. Therefore, a large area can be secured for the surface of the contact portion 11b that is in indirect or direct contact with the battery 200 and that exchanges heat with the battery 200.

[0055] In addition, in the first portion of the heat exchanger 100b, there are three first weld lines 32b, 32c, and 32d, and two second weld lines 32a and 32e. The amount of thermal strain caused by the joints of the heat exchanger varies depending on the distance between the neutral axis and the weld lines at the joints. Therefore, in a configuration like the heat exchanger 100b, in which the number of first weld lines 32b, 32c, and 32d is different from the number of second weld lines 32a and 32e, the shortest distance from the neutral axis N to the first weld lines and the shortest distance from the neutral axis N to the second weld lines are set to different values. In the configuration of the heat exchanger 100b, the shortest distances LC1, LC2, and LC3 from the neutral axis N to each of the first weld lines 32b, 32c, and 32d are set to, for example, 0.8 mm, and the shortest distances LD1 and LD2 from the neutral axis N to each of the second weld lines 32a and 32e are set to, for example, 1.2 mm. As a result, the sum of the shortest distances LC1, LC2, and LC3 from the neutral axis N to each of the first welding lines 32b, 32c, and 32d is approximately the same as the sum of the shortest distances LD1 and LD2 from the neutral axis N to each of the second welding lines 32a and 32e.

[0056] As a result, deformation of the heat exchanger 100b caused by contraction stress when the first weld lines 32b, 32c, and 32d cool is more likely to be offset by deformation of the heat exchanger 100b caused by contraction stress when the second weld lines 32a and 32e cool. This reduces the effects of thermal distortion on the heat exchanger 100b. That is, deformation of the first plate member 1b is reduced, and the two contact portions 11b of the first plate member 1b are more likely to come into indirect or direct contact with the battery 200. This improves the cooling performance of the heat exchanger 100b for the battery 200.

[0057] Furthermore, for example, a heat exchanger 100c of a third modified example shown in Fig. 9 may have a configuration in which 10 flow paths 4c are formed by 12 joints 3c. Specifically, the first plate member 1c may have two contact portions 11c and three non-contact portions 12c, and the second plate member 2c may have nine flat portions 21c and eight protrusions 22c. Note that for convenience, Fig. 9 illustrates only the configuration of a half portion (hereinafter referred to as the second portion) of the heat exchanger 100c on the first end S1 side, centered on the center line A, but the heat exchanger 100c has a structure that is axisymmetric with respect to the center line A in the cross section of the heat exchanger 100c.

[0058] In the second portion of the heat exchanger 100c, each joint 3c has a weld line. The second portion of the heat exchanger 100c has six weld lines 33a to 33f. The first weld lines 33b, 33c, 33d, and 33e are located in the contact portion 11c on the first end S1 side of the first plate member 1c. The second weld line 33a is located in the non-contact portion 12c on the first end S1 side of the first plate member 1c, and the second weld line 33f is located on the first end S1 side of the through holes 13 and 23 in the non-contact portion 12c located in the center of the first plate member 1c in the short direction S.

[0059] As a result, the portions of the contact portion 11c where the flow paths 4c are provided and the portions of the first welding lines 33b, 33c, 33d, and 33e are provided are in indirect or direct contact with the battery 200. Therefore, a large area can be secured for the surface of the contact portion 11c that is in indirect or direct contact with the battery 200 and that exchanges heat with the battery 200.

[0060] In the second portion of the heat exchanger 100c, the number of first welding lines 33b, 33c, 33d, and 33e is four, and the number of second welding lines 33a, 33f is two. Similar to the heat exchanger 100b, the number of first welding lines 33b, 33c, 33d, and 33e in the heat exchanger 100c is different from the number of second welding lines 33a, 33f in the heat exchanger 100c. Therefore, in the configuration of the heat exchanger 100c, the shortest distances LE1, LE2, LE3, and LE4 from the neutral axis N to each of the first welding lines 33b, 33c, 33d, and 33e are set to, for example, 0.7 mm, and the shortest distances LF1 and LF2 from the neutral axis N to each of the second welding lines 33a, 33f are set to, for example, 1.4 mm. As a result, the sum of the shortest distances LE1, LE2, LE3, and LE4 from the neutral axis N to each of the first welding lines 33b, 33c, 33d, and 33e is approximately the same as the sum of the shortest distances LF1 and LF2 from the neutral axis N to each of the second welding lines 33a and 33f.

[0061] As a result, deformation of the heat exchanger 100c caused by contraction stress when the first weld lines 33b, 33c, 33d, and 33e cool is more likely to be offset by deformation of the heat exchanger 100c caused by contraction stress when the second weld lines 33a and 33f cool. This reduces the effects of thermal distortion on the heat exchanger 100c. That is, deformation of the first plate member 1c is reduced, and the two contact portions 11c of the first plate member 1c are more likely to come into indirect or direct contact with the battery 200. This improves the cooling performance of the heat exchanger 100c for the battery 200.

[0062] (3c) In the above embodiment and the first to third modified examples, the configurations in which the shortest distance from the neutral axis N to each first welding line is constant and the shortest distance from the neutral axis N to each second welding line is constant have been exemplified. However, for example, as long as the sum of the shortest distances from the neutral axis N to each first welding line is approximately the same as the sum of the shortest distances from the neutral axis N to each second welding line, the values ​​of each shortest distance do not need to be constant.

[0063] (3d) In the above embodiment and first to third modified examples, the multiple weld lines are arranged in line symmetry with respect to the center line A in the cross section of the heat exchanger. However, for example, if the sum of the shortest distances from the neutral axis N to each of the first weld lines is approximately the same as the sum of the shortest distances from the neutral axis N to each of the second weld lines, the weld lines do not need to be arranged in line symmetry with respect to the center line A.

[0064] (3e) In the above embodiment and the first to third modified examples, the first and second weld lines extend in the longitudinal direction L of the heat exchanger 100b to form six flow paths 4. However, for example, the first and second weld lines may extend in the lateral direction S of the heat exchanger to form multiple flow paths through which the heat exchange medium flows.

[0065] (3f) In the above embodiment and the first to third modified examples, the first weld line is located at the contact portion 11 of the first plate member 1, but the first weld line does not have to be located at the contact portion.

[0066] (3g) In the above embodiment, the heat exchanger 100 is sized to correspond to the battery 200. However, as shown in FIG. 11 , a plurality of heat exchangers 100 may be connected in a line in the short-side direction S to correspond to a battery pack 220 shown in FIG. 10 that is arranged in an annular frame 600 and configured by combining a plurality of batteries 200. A heat exchange device 110 formed by connecting a plurality of heat exchangers 100 together is disposed so as to face the battery pack 220. In the example shown in FIG. 11 , the longitudinal direction L of the heat exchanger 100 corresponds to the left-right direction of the electric vehicle, and the short-side direction S of the heat exchanger 100 corresponds to the front-rear direction of the electric vehicle. Alternatively, the longitudinal direction L of the heat exchanger 100 may correspond to the front-rear direction of the electric vehicle, and the short-side direction S of the heat exchanger 100 may correspond to the left-right direction of the electric vehicle.

[0067] (3h) In the above embodiment, the shape of the flow path 4 in which the heat exchange medium flows from the inlet 101 to the outlet 102 along the arrows shown in Fig. 4 was exemplified, but the shape of the flow path is not limited to this. For example, as shown in Fig. 12, a heat exchanger 100d of a fourth modified example may have a flow path 4d shaped as shown by the arrows in which the heat exchange medium flows from the inlet 101d to the outlet 102d. Furthermore, as shown in Fig. 13, a heat exchanger 100e of a fifth modified example may have a flow path 4e shaped as shown by the arrows in which the heat exchange medium flows from the inlet 101e to the outlet 102e.

[0068] (3i) In the above embodiment, heat input to each joint 3 was performed under constant conditions in the joining step S30. That is, in the above embodiment, the amount of heat input when forming each weld line 31a-31h was approximately the same. However, for example, in the joining step S30, heat input to each joint may be performed under different conditions. That is, the amount of heat input when forming each weld line may be different.

[0069] Here, a change in the amount of heat input changes the contraction stress when the weld line cools. Therefore, for example, the influence of thermal distortion of the heat exchanger may be evaluated by taking into account the heat input when each weld line was formed, in addition to the shortest distance from the neutral axis N to each weld line. For example, in a configuration in which the heat exchanger has multiple weld lines and the heat input is taken into account, the sum of the values ​​obtained by multiplying the shortest distance from the neutral axis N to each first weld line by the heat input when each first weld line was formed may be approximately the same as the sum of the values ​​obtained by multiplying the shortest distance from the neutral axis N to each second weld line by the heat input when each second weld line was formed.

[0070] Specifically, in the case where the heat exchanger 100 has eight weld lines 31a-31h as in the above embodiment, ((shortest distance LA1 x heat input QA1) + (shortest distance LA2 x heat input QA2) + (shortest distance LA3 x heat input QA3) + (shortest distance LA4 x heat input QA4)) may be expressed as ((shortest distance LB1 x heat input QB1) + (shortest distance LB2 x heat input QB2) + (shortest distance LB3 x heat input QB3) + (shortest distance LB4 x heat input QB4)). The heat inputs QA1-QA4 are the amounts of heat input when forming the first weld lines 31b, 31c, 31f, and 31g. The heat inputs QB1-QB4 are the amounts of heat input when forming the second weld lines 31a, 31d, 31e, and 31h.

[0071] As a result, even if the contraction stresses of the weld lines differ due to different amounts of heat input, the deformation of the heat exchanger caused by the contraction stresses of the first weld lines when they cool is likely to be offset by the deformation of the heat exchanger caused by the contraction stresses of the second weld lines when they cool. Therefore, the effects of thermal distortion can be suppressed even in heat exchangers with joints that have heat input under different conditions during welding, taking into account the shape, thickness, size, etc. of the heat exchanger. In other words, taking the amount of heat input into account can broaden the design options for heat exchangers that improve cooling performance. Note that, even if the heat input to the joints is performed under consistent conditions in the joining step S30 and the amount of heat input during the formation of each weld line is approximately the same, the heat input during the formation of each weld line may be taken into account in addition to the shortest distance from the neutral axis to each weld line when evaluating the effects of thermal distortion on the heat exchanger.

[0072] (3j) The function of one component in the above embodiments may be distributed among multiple components, or the functions of multiple components may be integrated into one component. Also, part of the configuration of the above embodiments may be omitted. Furthermore, at least part of the configuration of the above embodiments may be added to or substituted for the configuration of another of the above embodiments.

[0073] [4. Technical Ideas Disclosed in the Present Specification] [Item 1] A heat exchanger that exchanges heat with a battery mounted on an electric vehicle, a first plate member that is a plate-shaped member configured to face the battery; a second plate member that is a plate-shaped member and is arranged to face the first plate member on the side opposite to the battery, and forms a flow path through which a heat exchange medium passes between the first plate member and the second plate member; a joint portion where the first plate member and the second plate member are joined by welding; Equipped with the joint portion has a plurality of weld lines extending in a first direction and arranged in a second direction perpendicular to the first direction to partition the flow path, the plurality of weld lines are respectively arranged on the first plate member side and the second plate member side with respect to a neutral axis extending in the second direction in a cross section of the heat exchanger perpendicular to the first direction, Among the plurality of weld lines, a weld line located closer to the first plate member than the neutral axis is defined as at least one first weld line, and a weld line located closer to the second plate member than the neutral axis is defined as at least one second weld line; A heat exchanger, wherein the sum of the shortest distances from the neutral axis to each of the at least one first weld line is approximately the same as the sum of the shortest distances from the neutral axis to each of the at least one second weld line.

[0074] [Item 2] Item 1, the heat exchanger according to item 1, the number of the at least one first weld line and the number of the at least one second weld line are the same; A heat exchanger, wherein the shortest distance from the neutral axis to each of the at least one first weld line and the shortest distance from the neutral axis to each of the at least one second weld line are the same.

[0075] [Item 3] The heat exchanger according to item 1 or 2, the plurality of weld lines are arranged symmetrically with respect to a center line in the cross section, A heat exchanger wherein the center line is a line that passes through the center of the cross section in the second direction and is perpendicular to the neutral axis.

[0076] [Item 4] The heat exchanger according to any one of items 1 to 3, A heat exchanger, wherein the first direction is a longitudinal direction of the heat exchanger.

[0077] [Item 5] The heat exchanger according to any one of items 1 to 4, the first plate member has a contact portion that is a portion that comes into contact with the battery, the contact portion being substantially parallel to the neutral axis and extending in a substantially planar shape in the first direction and the second direction; The at least one first weld line is disposed at the contact portion.

[0078] [Item 6] The heat exchanger according to any one of items 1 to 5, the plurality of weld lines are formed by heat input to the joint, a heat exchanger, wherein the sum of values ​​obtained by multiplying the shortest distance from the neutral axis to each of the at least one first weld line by the heat input amount when each of the at least one first weld line is formed is approximately equal to the sum of values ​​obtained by multiplying the shortest distance from the neutral axis to each of the at least one second weld line by the heat input amount when each of the at least one second weld line is formed.

[0079] [Item 7] A method for manufacturing a heat exchanger according to any one of items 1 to 5, placing the second plate member on the first plate member so that the first plate member and the second plate member abut at the joint portion; forming the plurality of weld lines by applying heat to the joint portion to join the first plate member and the second plate member; Equipped with a sum of values ​​obtained by multiplying the shortest distance from the neutral axis to each of the at least one first welding line by the heat input amount when each of the at least one first welding line is formed is approximately the same as a sum of values ​​obtained by multiplying the shortest distance from the neutral axis to each of the at least one second welding line by the heat input amount when each of the at least one second welding line is formed. [Explanation of symbols]

[0080] 1,1a~1c...First plate member, 2,2b,2c...Second plate member, 3,3b,3c...Joint part, 4,4b~4e...Flow path, 11,11b,11c...Contact part, 12,12b,12c...Non-contact part, 13,23...Through hole , 21,21b,21c...flat plate part, 22,22b,22c...convex part, 31b,31c,31f,31g,32b~32d,33b~33e...first welding line, 31a,31d,31e,31h,32a,32e ,33a,33f...second welding line, 100,100a~100e...heat exchanger, 101,101a,101d,101e...inlet, 102,102a,102d,102e...outlet, 110...heat exchange device, 200...battery, 201...contact surface, 220...battery pack, 300...thermal conductive material, 400,600...frame, 500...lower case, A...center line, L1,S1...first end, L2,S2...second end, N...neutral axis.

Claims

1. A heat exchanger that exchanges heat with a battery mounted on an electric vehicle, a first plate member that is a plate-shaped member configured to face the battery; a second plate member that is a plate-shaped member and is arranged to face the first plate member on the side opposite to the battery, and forms a flow path through which a heat exchange medium passes between the first plate member and the second plate member; a joint portion where the first plate member and the second plate member are joined by welding; Equipped with the joint portion has a plurality of weld lines extending in a first direction and arranged in a second direction perpendicular to the first direction to define the flow path, the plurality of weld lines are respectively arranged on the first plate member side and the second plate member side with respect to a neutral axis extending in the second direction in a cross section of the heat exchanger perpendicular to the first direction, Among the plurality of weld lines, a weld line located closer to the first plate member than the neutral axis is defined as at least one first weld line, and a weld line located closer to the second plate member than the neutral axis is defined as at least one second weld line, a sum of the shortest distances from the neutral axis to each of the at least one first weld line is approximately equal to a sum of the shortest distances from the neutral axis to each of the at least one second weld line.

2. 2. The heat exchanger of claim 1, the number of the at least one first weld line and the number of the at least one second weld line are the same; a shortest distance from the neutral axis to each of the at least one first weld line and a shortest distance from the neutral axis to each of the at least one second weld line are the same.

3. The heat exchanger according to claim 1 or 2, the plurality of weld lines are arranged symmetrically with respect to a center line in the cross section, A heat exchanger, wherein the center line is a line that passes through the center of the cross section in the second direction and is perpendicular to the neutral axis.

4. The heat exchanger according to claim 1 or 2, A heat exchanger, wherein the first direction is a longitudinal direction of the heat exchanger.

5. The heat exchanger according to claim 1 or 2, the first plate member has a contact portion that is a portion that comes into contact with the battery, the contact portion being substantially parallel to the neutral axis and extending in a substantially planar shape in the first direction and the second direction; The at least one first weld line is disposed at the contact portion.

6. The heat exchanger according to claim 1 or 2, the plurality of weld lines are formed by heat input to the joint, a heat exchanger, wherein a sum of values ​​obtained by multiplying the shortest distance from the neutral axis to each of the at least one first weld lines by the heat input amount when each of the at least one first weld lines is formed is approximately equal to a sum of values ​​obtained by multiplying the shortest distance from the neutral axis to each of the at least one second weld lines by the heat input amount when each of the at least one second weld lines is formed.

7. A method for manufacturing the heat exchanger according to claim 1, placing the second plate member on the first plate member so that the first plate member and the second plate member abut at the joint portion; forming the plurality of weld lines by applying heat to the joint portion to join the first plate member and the second plate member; Equipped with a sum of values ​​obtained by multiplying the shortest distance from the neutral axis to each of the at least one first weld lines by the heat input amount when each of the at least one first weld lines is formed is approximately equal to a sum of values ​​obtained by multiplying the shortest distance from the neutral axis to each of the at least one second weld lines by the heat input amount when each of the at least one second weld lines is formed.

Images