Heat exchanger and manufacturing method of heat exchanger

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] The present disclosure relates to a heat exchanger and a method for manufacturing a heat exchanger. [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 which the two plate-shaped members are joined, and a plurality of joints arranged 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 along the orthogonal direction of the heat exchanger. Patent Document 1 also discloses a configuration in which a plurality of joints are arranged away from the neutral axis on a cooling surface in contact with the battery, which is included in a plate-shaped member facing the battery and extends in a plane parallel to the neutral axis of the heat exchanger. [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 the joints are disposed on the neutral axis of the heat exchanger, the heat exchanger does not contact the battery at the positions where the joints are provided, and therefore the cooling surface of the heat exchanger that contacts the battery tends to become small, which causes a problem that the cooling performance of the heat exchanger for the battery tends to decrease.

[0005] In addition, when multiple joints are arranged on the flat 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 causes a problem that the cooling performance of the heat exchanger for the battery is easily degraded.

[0006] One aspect of the present disclosure aims to improve 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 disposed to face the first plate member on the opposite side 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. 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 the plurality of weld lines are aligned in a second direction perpendicular to the first direction to partition the flow path. The plurality of weld lines are respectively disposed 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, 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. 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 effect of thermal distortion on the heat exchanger having a joint formed by welding. In other words, deformation of the first plate member is suppressed, and the first plate member is more likely 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, the deformation of the heat exchanger caused by the first weld line is easily offset by the deformation of the heat exchanger caused by the second weld line, which reduces the influence 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 multiple 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 a center 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] According to 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 disclosure, the first direction may be a longitudinal direction of the heat exchanger. 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, so that the above-described configuration makes it easier to suppress the influence of the thermal distortion of the heat exchanger.

[0014] In one embodiment 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 planarly in the first and second directions. At least one first weld line may be disposed on the contact portion.

[0015] According to this configuration, the area of ​​the contact portion where the flow path is provided and the area of ​​the contact portion where the first weld line is provided come into contact with the battery, so that the area of ​​the surface of the contact portion that comes into contact with the battery and exchanges heat with the battery can be increased, thereby further improving the cooling performance of the heat exchanger for the battery.

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

[0017] In this configuration, the heat input amount at the time of forming each weld line is taken into account in the evaluation of the influence of thermal distortion of the heat exchanger in addition to the shortest distance from the neutral axis to each weld line. As a result, even if the heat input amount at the time of forming each weld line is different and the contraction stress at the time of cooling is different, the deformation caused in the heat exchanger by the first weld line is easily offset by the deformation caused in the heat exchanger by the second weld line. Therefore, the influence of thermal distortion is suppressed even in a heat exchanger having joints to which heat is input under different conditions at the time of welding. Therefore, the cooling performance of the heat exchanger for the battery can be improved.

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

[0019] In this configuration, the heat input amount at the time of forming each weld line is taken into account in the evaluation of the influence of thermal distortion of the heat exchanger in addition to the shortest distance from the neutral axis to each weld line. As a result, even if the heat input amount at the time of forming each weld line is different and the contraction stress at the time of cooling is different, the deformation caused in the heat exchanger by the first weld line is easily offset by the deformation caused in the heat exchanger by the second weld line. Therefore, the influence of thermal distortion is suppressed even in a heat exchanger having joints to which heat is input under different conditions at the time of welding. Therefore, the cooling performance of the heat exchanger for the battery can be improved. [Brief description of the drawings]

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

[0021] Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings. [1. Configuration] A 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 electric energy stored in a battery as the vehicle's power. Electric vehicles include electric vehicles, plug-in hybrid vehicles, hybrid vehicles, fuel cell vehicles, and the like. The heat exchanger 100 is configured so that a heat exchange medium such as cooling water flows inside. The heat exchanger 100 includes 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 longitudinal 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 longitudinal 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 have to be disposed between the heat exchanger and the battery. The frame 400 is provided so as to go around the side surface of the battery 200 that extends perpendicularly 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, FIG. 2 omits the illustration of a part of the frame 400.

[0024] The heat exchanger 100 may have a longitudinal direction L corresponding to the front-to-rear direction of the electric vehicle and a short side 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 short side 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 a contact surface 201 of the battery 200. The first plate member 1 is made of a metal having high thermal conductivity, such as aluminum. The first plate member may be made of a metal having 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 indirectly or directly contacts the battery 200, and is generally parallel to a neutral axis N extending in a 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 a line that intersects the cross section and 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 the compressive force are balanced, 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 portion 12 extends 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 (for example, upward) with respect to the three non-contact portions 12. That is, 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 need 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 plate material having a substantially rectangular shape, and is disposed so as to face the first plate member 1 and the battery 200 on the opposite side. For example, when 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 disposed below or above the first plate member 1. Also, when 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 disposed to the left, right, front, or rear of the first plate member 1. The second plate member 2 is made of a metal having a high thermal conductivity, such as aluminum, similar to the first plate member 1. The second plate member 2 may be made of a metal having a 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 portion 21 is a portion that does not contact the contact portion 11 of the first plate member 1, and extends in a substantially planar manner in the longitudinal direction L and the lateral direction S, approximately parallel to the neutral axis N. 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 the first end S1 in the lateral direction S, one flat plate portion 21 located at the second end S2 in the lateral direction S, and one flat plate portion 21 located at the center of the second plate member 2 contact the non-contact portions 12 of the first plate member 1 facing the respective flat plate portions 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 plurality of through holes 23 are arranged at intervals from each other in the longitudinal direction L. Each through hole 23 of the second plate member 2 overlaps with each through hole 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 the welding.

[0032] The joints 3 are provided at locations where the contact portions 11 of the first plate member 1 and the convex portions 22 of the second plate member 2 come into contact with each other, and where the non-contact portions 12 of the first plate member 1 and the flat plate portions 21 of the second plate member 2 come into contact with each other. 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 come into contact with each other, but face each other with a gap therebetween. As a result, six flow paths 4 through which the heat exchange medium passes are formed between the first plate member 1 and the second plate member 2.

[0033] As shown in FIG. 3 and FIG. 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 to divide the space between the first plate member 1 and the second plate member 2 into the above-mentioned six flow paths 4. A part of the eight weld lines 31a to 31h is disposed on the first plate member 1 side with respect to the neutral axis N, and the remaining part is disposed on the second plate member 2 side. In the following description, among the eight weld lines 31a to 31h, the weld lines located on the first plate member 1 side of the neutral axis N are also referred to as first weld lines 31b, 31c, 31f, and 31g, and the weld lines located on the second plate member 2 side of the neutral axis N are also 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 short side direction S of the cross section of the heat exchanger 100 and is perpendicular to the neutral axis N.

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

[0036] Furthermore, the sum of the shortest distances LA1, LA2, LA3, LA4 from the neutral axis N to each of the first welding lines 31b, 31c, 31f, 31g is substantially equal to the sum of the shortest distances LB1, LB2, LB3, LB4 from the neutral axis N to each of the second welding lines 31a, 31d, 31e, 31h. In this embodiment, the number of the first welding lines 31b, 31c, 31f, 31g and the number of the second welding lines 31a, 31d, 31e, 31h are the same, that is, four, and the shortest distances LA1, LA2, LA3, LA4 and the shortest distances LB1, LB2, LB3, LB4 are 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 of the weld lines 31a to 31h in the longitudinal direction L are also connected by a weld 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 FIG. 4.

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

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

[0040] (Placement process) Next, the second plate member 2 is placed on 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 protruding portions 22 and the three non-contact portions 12 abut against the three flat portions 21 facing them.

[0041] (Joining process) Next, eight welding lines 31a to 31h are formed by heat input to each joint 3, and the first plate member 1 and the second plate member 2 are joined together. Specifically, for example, a laser beam is irradiated to each joint 3 along the longitudinal direction L. As a result, the eight welding lines 31a to 31h are formed such that the first welding lines 31b, 31c, 31f, and 31g and the second welding lines 31a, 31d, 31e, and 31h are disposed 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 melting the first plate member 1 and the second plate member 2 with heat input from a laser beam or the like to each joint 3. In this embodiment, heat input to each joint 3 is performed under constant conditions in the joining step S30. That is, the amount of heat input when each of the weld lines 31a-31h is formed is approximately the same. The amount of heat input is calculated by (welding output ÷ welding speed × welding length).

[0043] [2. Effects] According to the embodiment described above in detail, the following effects can be obtained. (2a) In this embodiment, 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 a result, the deformation of the heat exchanger 100 caused by the contraction stress when the first welding lines 31b, 31c, 31f, 31g cool is easily offset by the deformation of the heat exchanger 100 caused by the contraction stress when the second welding lines 31a, 31d, 31e, 31h cool. Therefore, the influence of thermal distortion of the heat exchanger 100 having eight joints 3 is suppressed. That is, the deformation of the first plate member 1 is suppressed, and the two contact portions 11 of the first plate member 1 are easily brought into indirect or direct contact with the battery 200. In other words, the surface of each contact portion 11 facing the battery 200 and exchanging heat with the battery 200 is easily maintained in a flat state. This can improve 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 is also improved.

[0044] (2b) In this embodiment, the first welding lines 31b, 31c are disposed at the contact portion 11 on the first end S1 side of the first plate member 1, and the first welding lines 31f, 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 where each first welding line 31b, 31c, 31f, 31g is provided are in indirect or direct contact with the battery 200. Therefore, the surface area of ​​the surface of each contact portion 11 that indirectly or directly contacts the battery 200 and exchanges heat with the battery 200 can be secured to be large. Therefore, the cooling performance of the heat exchanger 100 for the battery 200 can be further improved.

[0045] (2c) In this embodiment, the eight weld lines 31a to 31h are arranged in line symmetry 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. For this reason, 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 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 Fig. 5 to Fig. 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 provided so as to go around the side surface of the battery 200, and the inlet 101a and the outlet 102a are located outside the frame 400. In FIG. 6, for convenience, a part of the frame 400 is omitted from illustration. The heat exchanger 100a of the first modified example can also play the role of a lower case. Therefore, 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, unlike the heat exchanger 100 of the above embodiment.

[0051] (3b) In the above embodiment, the heat exchanger 100 is illustrated in which six flow paths 4 are formed by eight joints 3 having the first weld lines 31b, 31c, 31f, and 31g and the second weld 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 thereto, and the number of flow paths, i.e., the number of weld lines, is not limited thereto.

[0052] For example, the heat exchanger 100b of the 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 plate portions 21b and six protruding portions 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 with respect to the center line A, but the heat exchanger 100b has a structure that is axisymmetric with respect to the center line A in the cross section of the heat exchanger 100b.

[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 disposed in the contact portion 11b on the first end S1 side of the first plate member 1b. The second weld line 32a is disposed in the non-contact portion 12b of the first end S1 of the first plate member 1b, and the second weld line 32e is disposed on the first end S1 side of the through holes 13 and 23 in the non-contact portion 12b located in the center in the short direction S of the first plate member 1b.

[0054] As a result, a portion of the contact portion 11b where each flow path 4b is provided and a portion of the contact portion 11b where each first weld line 32b, 32c, 32d is 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, the number of the first welding lines 32b, 32c, 32d is three, and the number of the second welding lines 32a, 32e is two. The amount of deformation due to thermal strain caused by the joints of the heat exchanger varies depending on the distance between the neutral axis and the welding lines of the joints. For this reason, in the case of a configuration in which the number of the first welding lines 32b, 32c, 32d is different from the number of the second welding lines 32a, 32e, as in the heat exchanger 100b, the shortest distance from the neutral axis N to the first welding lines and the shortest distance from the neutral axis N to the second welding lines are set to different values. In the configuration of the heat exchanger 100b, the shortest distances LC1, LC2, LC3 from the neutral axis N to the first welding lines 32b, 32c, 32d are set to, for example, 0.8 mm, and the shortest distances LD1, LD2 from the neutral axis N to the second welding lines 32a, 32e are set to, for example, 1.2 mm. As a result, the sum of the shortest distances LC1, LC2, LC3 from the neutral axis N to each of the first weld lines 32b, 32c, 32d is approximately the same as the sum of the shortest distances LD1, LD2 from the neutral axis N to each of the second weld lines 32a, 32e.

[0056] As a result, the deformation of the heat exchanger 100b caused by the contraction stress when the first welded lines 32b, 32c, and 32d cool is easily offset by the deformation of the heat exchanger 100b caused by the contraction stress when the second welded lines 32a and 32e cool. This suppresses the influence of thermal distortion of the heat exchanger 100b. That is, the deformation of the first plate member 1b is suppressed, and the two contact portions 11b of the first plate member 1b are easily brought into indirect or direct contact with the battery 200. This improves the cooling performance of the heat exchanger 100b for the battery 200.

[0057] Also, 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 plate portions 21c and eight protruding portions 22c. For convenience, Fig. 9 illustrates only the configuration of a half portion (hereinafter referred to as a second portion) of the heat exchanger 100c on the first end S1 side with respect to 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 disposed in the contact portion 11c on the first end S1 side of the first plate member 1c. The second weld line 33a is disposed in the non-contact portion 12c of the first end S1 of the first plate member 1c, and the second weld line 33f is disposed 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 short side direction S of the first plate member 1c.

[0059] As a result, a portion of the contact portion 11c where each flow path 4c is provided and a portion of the contact portion 11c where each first weld line 33b, 33c, 33d, 33e is 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 the first welding lines 33b, 33c, 33d, 33e is four, and the number of the second welding lines 33a, 33f is two. As with the heat exchanger 100b, the number of the first welding lines 33b, 33c, 33d, 33e and the number of the second welding lines 33a, 33f of the heat exchanger 100c are different. Therefore, in the configuration of the heat exchanger 100c, the shortest distances LE1, LE2, LE3, LE4 from the neutral axis N to each of the first welding lines 33b, 33c, 33d, 33e are set to, for example, 0.7 mm, and the shortest distances LF1, 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, LF2 from the neutral axis N to each of the second welding lines 33a, 33f.

[0061] As a result, the deformation of the heat exchanger 100c caused by the contraction stress when the first welded lines 33b, 33c, 33d, and 33e cool is easily offset by the deformation of the heat exchanger 100c caused by the contraction stress when the second welded lines 33a and 33f cool. This suppresses the influence of thermal distortion of the heat exchanger 100c. That is, the deformation of the first plate member 1c is suppressed, and the two contact portions 11c of the first plate member 1c are easily brought 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 configuration in which the shortest distance from the neutral axis N to each of the first welding lines is constant and the shortest distance from the neutral axis N to each of the second welding lines is constant has been exemplified. However, for example, as long as the sum of the shortest distances from the neutral axis N to each of the first welding lines is substantially the same as the sum of the shortest distances from the neutral axis N to each of the second welding lines, the values ​​of each shortest distance do not need to be constant.

[0063] (3d) In the above embodiment and the first to third modified examples, the multiple weld lines are arranged in a cross section of the heat exchanger in line symmetry with respect to the center line A. However, for example, if the sum of the shortest distances from the neutral axis N to each of the first weld lines is substantially 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 a plurality of 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 disposed at the contact portion 11 of the first plate member 1, but the first weld line does not have to be disposed at the contact portion.

[0066] (3g) In the above embodiment, the heat exchanger 100 having a size corresponding to the battery 200 is exemplified. However, as shown in FIG. 11, a plurality of heat exchangers 100 may be connected in parallel in the short-side direction S to correspond to a battery pack 220 shown in FIG. 10 that is arranged in a ring-shaped frame 600 and configured by combining a plurality of batteries 200. A heat exchange device 110 in which a plurality of heat exchangers 100 are connected together is arranged 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. Note that 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 is 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 in the shape shown by the arrows in which the heat exchange medium flows from the inlet 101d to the outlet 102d. Also, for example, as shown in Fig. 13, a heat exchanger 100e of a fifth modified example may have a flow path 4e in the shape 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, in the joining step S30, heat input to each joint 3 was performed under constant conditions. That is, in the above embodiment, the amount of heat input when each weld line 31a-31h was formed 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 each weld line is formed may be different.

[0069] Here, if the amount of heat input changes, the contraction stress when the weld line cools changes. Therefore, for example, the influence of thermal distortion of the heat exchanger may be evaluated by taking into account the amount of heat input when each weld line is 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 a plurality of weld lines, when the amount of heat input is taken into account, the total value of the values ​​obtained by multiplying the shortest distance from the neutral axis N to each first weld line by the amount of heat input when each first weld line is formed may be approximately equal to the total value of the values ​​obtained by multiplying the shortest distance from the neutral axis N to each second weld line by the amount of heat input when each second weld line is formed.

[0070] Specifically, in the case where the heat exchanger 100 has eight welding lines 31a to 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 to QA4 are the heat inputs when the first welding lines 31b, 31c, 31f, and 31g are formed. The heat inputs QB1 to QB4 are the heat inputs when the second welding lines 31a, 31d, 31e, and 31h are formed.

[0071] As a result, even if the heat input amount is different and the contraction stress when each weld line cools is different, the deformation caused in the heat exchanger due to the contraction stress when each first weld line cools is easily offset by the deformation caused in the heat exchanger due to the contraction stress when each second weld line cools. Therefore, even in a heat exchanger having a joint where heat is input under different conditions during welding, the influence of thermal distortion can be suppressed by taking into account the shape, thickness, size, etc. of the heat exchanger. That is, by taking into account the heat input amount, the range of design of a heat exchanger with improved cooling performance is easily expanded. Note that in the joining process S30, even if the heat input to the joint is performed under constant conditions and the heat input amount when each weld line is formed is approximately the same, the heat input amount when each weld line is formed may be taken into account in addition to the shortest distance from the neutral axis to each weld line in the evaluation of the influence 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. Also, 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 Concepts Disclosed in This Specification] [Item 1] A heat exchanger for exchanging 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 each other on the opposite side of the first plate member and 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 disposed 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 on the first plate member side of the neutral axis is defined as at least one first weld line, and a weld line located on the second plate member side of 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 the same as a sum of the shortest distances from the neutral axis to each of the at least one second weld line.

[0074] [Item 2] Item 1. A 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 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.

[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] A 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] A heat exchanger according to any one of items 1 to 4, the first plate member has a contact portion which 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] A 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 sum of values ​​obtained by multiplying a shortest distance from the neutral axis to each of the at least one first weld line by an amount of heat input when each of the at least one first weld line is formed is substantially equal to a sum of values ​​obtained by multiplying a shortest distance from the neutral axis to each of the at least one second weld line by an amount of heat input when each of the at least one second weld line is formed.

[0079] [Item 7] A method for producing 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 inputting 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 a shortest distance from the neutral axis to each of the at least one first weld line by an amount of heat input when each of the at least one first weld line is formed is substantially equal to a sum of values ​​obtained by multiplying a shortest distance from the neutral axis to each of the at least one second weld line by an amount of heat input when each of the at least one second weld 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 to 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 for exchanging 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 opposite side 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 includes 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 passage, The plurality of weld lines are disposed 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 the same as 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 equal; 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 which 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 sum of values ​​obtained by multiplying a shortest distance from the neutral axis to each of the at least one first weld line by an amount of heat input when each of the at least one first weld line is formed is substantially equal to a sum of values ​​obtained by multiplying a shortest distance from the neutral axis to each of the at least one second weld line by an amount of heat input when each of the at least one second weld line is formed.

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

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