Cooling member, method for manufacturing the same, and mold

Abstract

This invention provides a manufacturing method that enables the production of a cooling member as an integrated component having a hollow cross-section. [Solution] The method for manufacturing the cooling member (10, 10A, 10B, 10C) comprises a preparation step and a molding step. In the molding step, the flange surfaces (222) of the first mold (21) and the second mold (22) hold the flange portion (122) of the first blank (31) and the second blank (32, 32A, 32Ba, 32Bb, 32C), respectively, and a fluid is supplied between the first blank (31) and the second blank (32, 32A, 32Ba, 32Bb, 32C), thereby molding the main body (121) in the hollow space using the fluid. The total area of ​​the region on the surface (111) of the first member (11) where the refrigerant flow path (13) is provided is 50% or more and less than 90% of the area of ​​the smallest quadrilateral (R1) that circumscribes the second member (12, 12A, 12Ba, 12Bb, 12C) within the range of the surface (111).

Description

Technical Field

[0001] The present disclosure relates to a cooling member and a method for manufacturing the same. The present disclosure also relates to a mold, and more specifically, to a mold for manufacturing a cooling member.

Background Art

[0002] For example, electric vehicles, hybrid vehicles, etc. are equipped with a battery unit. As described in Patent Document 1, the battery unit includes, for example, a battery module and a battery case (housing case). The battery module includes a plurality of battery cells. The battery case houses the battery module.

[0003] The battery unit is required to have a cooling function for the battery cells to operate stably at an appropriate temperature. In the battery unit of Patent Document 1, a flow path forming plate is provided on the bottom plate of the battery case. The flow path forming plate forms a refrigerant flow path while maintaining a predetermined interval from the bottom plate of the battery case. In the battery unit of Patent Document 1, more than 90% of the area on the back surface of the bottom plate of the battery case is the area of the refrigerant flow path. According to Patent Document 1, with such a configuration, the battery module including a plurality of battery cells is cooled evenly regardless of its position in the battery case. Also, since the in-plane heat conduction of the bottom plate of the battery case hardly affects the cooling of the battery module, even if the bottom plate of the battery case is formed of a steel plate with a relatively low thermal conductivity, the battery module can be efficiently cooled.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In recent years, there has been a demand for reducing greenhouse gas emissions (life cycle GHGs) throughout the entire lifecycle of vehicles such as automobiles. To reduce life cycle GHG emissions by reducing the number of parts in the vehicle body and eliminating manufacturing processes, the integration of parts is progressing. In the cooling structure of a battery unit, a hollow cross-section is formed at the location of the refrigerant flow path. In order to promote the integration of parts and make their manufacturing more efficient, it is preferable that the parts forming such hollow cross-sections are also integrated.

[0006] The object of this disclosure is to provide a manufacturing method that can produce a cooling member as an integrated component having a hollow cross-section. [Means for solving the problem]

[0007] The manufacturing method relating to this disclosure is a method for manufacturing a cooling member. The cooling member includes a plate-shaped first member and a plurality of second members that together with the first member form a refrigerant flow path. Each second member includes a flange portion and a main body portion. The flange portion is positioned on one surface of the first member. The main body portion has a convex shape relative to the flange portion. The manufacturing method comprises the steps of preparing a material including a first blank and a plurality of second blanks superimposed on the first blank, and using a first mold and a second mold to form a first member from the first blank and a second member from the second blank. In the material, through holes are formed in the first blank at positions corresponding to each of the second blanks, or in each of the second blanks. The second mold includes a flange surface and a plurality of molding surfaces corresponding to the second blanks. Each molding surface has a concave shape relative to the flange surface. In the molding process, the flange portion of each of the first and second blanks is clamped between the first mold and the flange surface, and fluid is supplied between the first and second blanks. The fluid causes each of the second blanks to expand within the hollow space formed between the first mold and the molding surface, thereby forming the main body. The total area of ​​the region on the surface of the first member where the refrigerant flow path is provided is 50% or more and less than 90% of the area of ​​the smallest rectangle that circumscribes the second member within the range of that surface. [Effects of the Invention]

[0008] According to the manufacturing method described herein, a cooling member can be manufactured as an integrated component having a hollow cross-section. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a perspective view showing the schematic configuration of the cooling member according to the first embodiment. [Figure 2] Figure 2 is a cross-sectional view of the cooling member shown in Figure 1, taken along line II-II. [Figure 3A] Figure 3A is a perspective view showing the schematic configuration of the mold according to the first embodiment. [Figure 3B] Figure 3B is another perspective view showing the schematic configuration of the mold according to the first embodiment. [Figure 4] Figure 4 is a partial longitudinal cross-sectional view of the mold according to the first embodiment. [Figure 5] Figure 5 shows an example of a different mold from the one in Figure 4. [Figure 6] Figure 6 is a partial cross-sectional view of the mold according to the first embodiment. [Figure 7A] Figure 7A is a schematic diagram illustrating the manufacturing method of the cooling member according to the first embodiment. [Figure 7B] Figure 7B is a schematic diagram illustrating the manufacturing method of the cooling member according to the first embodiment. [Figure 7C] Figure 7C is a schematic diagram illustrating the manufacturing method of the cooling member according to the first embodiment. [Figure 7D] Figure 7D is a schematic diagram illustrating the manufacturing method of the cooling member according to the first embodiment. [Figure 7E] Figure 7E is a schematic diagram illustrating the manufacturing method of the cooling member according to the first embodiment. [Figure 7F] Figure 7F is a schematic diagram illustrating the manufacturing method of the cooling member according to the first embodiment. [Figure 7G] Figure 7G is a schematic diagram illustrating the manufacturing method of the cooling member according to the first embodiment. [Figure 8A] Figure 8A is a partial cross-sectional view of a cooling member manufactured by the manufacturing method according to the first embodiment. [Figure 8B] Figure 8B is a perspective view of a cooling member manufactured by the manufacturing method according to the first embodiment. [Figure 9] Figure 9 is a bottom view of the cooling member according to the second embodiment. [Figure 10A] Figure 10A is a schematic diagram showing a method for manufacturing a cooling member according to the second embodiment. [Figure 10B] Figure 10B is a schematic diagram showing a method for manufacturing a cooling member according to the second embodiment. [Figure 11] Figure 11 is a bottom view of the cooling member according to the third embodiment. [Figure 12A]FIG. 12A is a schematic diagram showing a method for manufacturing a cooling member according to the third embodiment. [Figure 12B] FIG. 12B is a schematic diagram showing a method for manufacturing a cooling member according to the third embodiment. [Figure 13] FIG. 13 is a perspective view of a cooling member according to the fourth embodiment. [Figure 14] FIG. 14 is a cross-sectional view taken along the XIV-XIV line of the cooling member shown in FIG. 13. [Figure 15A] FIG. 15A is a schematic diagram showing a method for manufacturing a cooling member according to the fourth embodiment. [Figure 15B] FIG. 15B is a schematic diagram showing a method for manufacturing a cooling member according to the fourth embodiment. MODE FOR CARRYING OUT THE INVENTION

[0010] The manufacturing method according to the embodiment is a method for manufacturing a cooling member. The cooling member includes a plate-shaped first member and a plurality of second members that, together with the first member, form a refrigerant flow path. Each second member includes a flange portion and a main body portion. The flange portion is positioned on one surface of the first member. The main body portion has a convex shape relative to the flange portion. The manufacturing method comprises the steps of preparing a material including a first blank and a plurality of second blanks superimposed on the first blank, and using a first mold and a second mold to form a first member from the first blank and a second member from the second blank. In the material, through holes are formed in the first blank at positions corresponding to each of the second blanks, or in each of the second blanks. The second mold includes a flange surface and a plurality of molding surfaces corresponding to the second blanks. Each molding surface has a concave shape relative to the flange surface. In the molding process, the flange portion of each of the first and second blanks is clamped between the first mold and the flange surface, and fluid is supplied between the first and second blanks. The fluid causes each of the second blanks to expand within the hollow space formed between the first mold and the molding surface, thereby forming the main body. The total area of ​​the region on the surface of the first member where the refrigerant flow path is provided is 50% or more and less than 90% of the area of ​​the smallest rectangle that circumscribes the second member within the range of that surface (first configuration).

[0011] In the manufacturing method relating to the first configuration, a cooling member is manufactured in which a plate-shaped first member and a plurality of second members that form a refrigerant flow path together with the first member are integrated. More specifically, the first member is formed from a first blank by a first mold and a second mold, and the second members are formed from a second blank. In the process of forming the first and second members, the first blank and the flange portion of each second blank are sandwiched between the flange surfaces of the first mold and the second mold. By supplying fluid between the first blank and the second blank in this state, the second blank is expanded in the hollow space formed by the molding surfaces of the first and second molds. At this time, the first member is formed from the first blank by the first mold, and the second blank is pressed against the molding surface of the second mold in the hollow space to form the main body of the second member. The main body of the second member, together with the first member, forms a hollow closed cross-section in which the interior becomes a refrigerant flow path.

[0012] In the manufacturing method relating to the first configuration, by utilizing a fluid, a cooling member having a hollow cross-section can be formed with the first member and the second member integrated from the material stage. Therefore, according to the manufacturing method relating to the first configuration, a cooling member can be manufactured as an integrated component having a hollow cross-section.

[0013] In the manufacturing method relating to the first configuration, the molding step may include the steps of: clamping the flange portion of each of the first blank and the second blank between the first mold and the flange surface with projections provided on the first mold or flange surface inserted into each of the through holes, thereby creating a gap between the first blank and the second blank with the projections; and supplying fluid from the projections into the gap, thereby inflating each of the second blanks within the hollow space with the fluid and forming the main body (second configuration).

[0014] Conventional molding technologies for parts with hollow cross-sections include hydroforming of sheet materials and hydraulic or gas blow molding of pipe materials. However, conventional hydroforming technology requires pre-forming of the overlapping sheet materials to ensure fluid passages, which presents challenges in productivity. Hydraulic or gas blow molding of pipe materials has the problem that only tubular parts can be molded. In contrast, in the manufacturing method of the cooling member according to the second configuration, the projections of the first mold or the second mold are inserted into through holes formed in the first blank or the second blank, and the flange surfaces of the first mold and the flange portion of each second blank are sandwiched between them. As a result, the first blank or each second blank is lifted by the projections, creating a gap between the first blank and each second blank, and a fluid passage is naturally formed. Therefore, there is no need to separately perform pre-forming to ensure fluid passages. Consequently, a cooling member as an integrated part with a hollow cross-section can be manufactured with high productivity.

[0015] In the manufacturing method relating to the first or second configuration, the second member may have a Vickers hardness of 120 HV or higher (third configuration).

[0016] A manufacturing method relating to any of the first to third configurations may further include a step of heating the material before the molding step (fourth configuration).

[0017] In the manufacturing method relating to the fourth configuration, the second member may have a Vickers hardness of 300 HV or more (fifth configuration).

[0018] The mold according to the embodiment is a mold for manufacturing a cooling member from a material including a first blank and a plurality of second blanks superimposed on the first blank. The mold comprises a first mold, a second mold, and a convex bead portion. The second mold includes a flange surface and a plurality of molding surfaces. The flange surface is configured to clamp the material together with the first mold. The molding surfaces have a concave shape relative to the flange surface. Each molding surface is configured to form a hollow space with the first mold. The bead portion is provided in at least one of the first mold and the second mold so as to surround each of the hollow spaces. At least one of the first mold and the second mold is provided with a fluid supply passage for supplying fluid to the hollow space (sixth configuration).

[0019] The mold relating to the sixth configuration is used to manufacture a cooling member from a material including a first blank and a plurality of second blanks that are stacked and joined together. This mold includes a first mold and a second mold. Each molding surface of the second mold, together with the first mold, forms a hollow space. By supplying fluid into this hollow space through a fluid supply passage, the second blanks can be inflated within the hollow space. Within the hollow space, each of the second blanks is pressed against the molding surface of the second mold to form the main body of the second member. The main body of the second member, together with the first member formed from the first blank by the first mold, forms a hollow closed cross-section whose interior serves as a coolant flow path.

[0020] By using the mold according to the sixth configuration, a cooling member having a hollow cross-section can be molded with the first member and the second member integrated from the material stage. In other words, a cooling member as an integrated component having a hollow cross-section can be suitably manufactured using the mold according to the sixth configuration.

[0021] In the sixth configuration, a bead portion is provided on at least one of the first mold and the second mold. The bead portion is positioned to surround each of the hollow spaces formed by the molding surfaces of the first mold and the second mold. When the first mold and the second mold are closed, this bead portion firmly presses the first blank and the second blank on the outer circumference of the hollow space. As a result, fluid leakage from between the first blank and the second blank is reduced. Therefore, the molding of cooling members using fluid can be performed more effectively.

[0022] The mold according to the sixth configuration may further include a convex sealing portion. The sealing portion is provided on at least one of the first mold and the second mold. The sealing portion is arranged to surround the bead portion (seventh configuration).

[0023] In the seventh configuration, a sealing portion is provided in at least one of the first mold and the second mold. The sealing portion is provided so as to surround the bead portion. This sealing portion allows the material to be sealed in the first mold and the second mold when the first mold and the second mold are closed. As a result, fluid leakage to the outside of the first mold and the second mold is reduced, and the molding of cooling members using fluid can be performed even more effectively.

[0024] The cooling member according to this embodiment comprises a plate-shaped first member and a plurality of second members. Each second member includes a flange portion and a main body portion. The flange portion is arranged on one surface of the first member. The main body portion has a shape that is convex with respect to the flange portion. The second members together with the first member form a refrigerant flow path. The total area of ​​the region on the surface of the first member where the refrigerant flow path is provided is 50% or more and less than 90% of the area of ​​the smallest rectangle that circumscribes the second member within the range of said surface. At each side edge in the width direction of the first member, at least one of the second members protrudes outward from the first member. In each of the second members, the rate of reduction in plate thickness at the center of the main body portion relative to the plate thickness of the flange portion is 5.0% or more (8th configuration).

[0025] The cooling member relating to the eighth configuration can be manufactured using the manufacturing method relating to any of the first to fifth configurations. That is, the main body portion that forms a refrigerant flow path together with the first member in each second member can be formed using a fluid. In this case, a reduction in plate thickness occurs in the main body portion of each second member. Specifically, in the eighth configuration, the rate of reduction in plate thickness at the center of the main body portion, based on the plate thickness of the flange portion, is 5.0% or more in each second member. By reducing the plate thickness at the center of the main body portion in this way, heat transfer between the refrigerant and each second member is improved, and the cooling performance of each second member can be enhanced. Furthermore, by using a fluid for forming, the plate thickness at the center and near the center of the main body portion of each second member is reduced relatively uniformly during forming. Consequently, in the case of cold forming, work hardening occurs from the center of the main body portion to both sides in each second member. In the case of hot forming, the thinned main body portion due to the plate thickness reduction is more easily cooled during the forming process, and an increase in hardness due to quenching occurs more easily in the main body portion. As a result, the second member can be given high strength.

[0026] In the cooling member according to the eighth configuration, at least one second member protrudes outward from the first member at each side edge in the width direction of the first member. Therefore, when a collision load is applied to the cooling member from the width direction of the first member, the second member can support the collision load and absorb the collision energy. For example, when subjected to a collision load, the second member protruding from the first member in its width direction can preferentially deform and absorb the collision energy. In other words, the cooling member can be given collision resistance. In the eighth configuration, as described above, the main body of each second member has high strength, so the cooling member can exhibit better collision resistance.

[0027] In the cooling member according to the eighth configuration, the second member may have a Vickers hardness of 120 HV or more (ninth configuration).

[0028] In the cooling member relating to the eighth or ninth configuration, the Vickers hardness measured at the center of the main body of each of the second members may be 105% or more of the Vickers hardness measured at the flange portion (tenth configuration).

[0029] Embodiments of this disclosure will be described below with reference to the drawings. In these drawings, the same or equivalent components are denoted by the same reference numerals, and the same description will not be repeated.

[0030] <First Embodiment> [Cooling components] Figure 1 is a perspective view showing the schematic configuration of the cooling member 10 according to this embodiment. The cooling member 10 is used, for example, in the body of an automobile. More specifically, the cooling member 10 can be used in a battery unit mounted on the body of an electric vehicle or a hybrid vehicle. In a battery unit, the cooling member 10 is used to cool the battery cells housed in the battery case.

[0031] Referring to Figure 1, the cooling member 10 comprises a first member 11 and a plurality of second members 12. The cooling member 10 comprises two or more second members 12, preferably three or more second members 12. The first member 11 has a substantially plate-like shape. The second members 12 are arranged on the first member 11.

[0032] In this embodiment, the multiple second members 12 are arranged substantially in parallel. Each of the second members 12 has an elongated shape. Each of the second members 12 extends in the width direction of the first member 11. The width direction of the first member 11 substantially coincides with the left-right direction (vehicle width direction) of the vehicle body to which the cooling member 10 is applied. That is, in this embodiment, each of the second members 12 extends in the vehicle width direction when the cooling member 10 is attached to the vehicle body.

[0033] Each of the second members 12 includes a body portion 121 and a flange portion 122. In this embodiment, each of the second members 12 includes two flange portions 122. Each of the flange portions 122 is positioned on one surface 111 of the first member 11. The flange portions 122 are positioned on both sides of the body portion 121 when viewed along the longitudinal direction of the second member 12. The body portion 121 has a convex shape relative to the flange portions 122. In this embodiment, the body portion 121 and the flange portions 122 extend along the longitudinal direction of the second member 12.

[0034] At each side edge of the first member 11 in the width direction, at least one of the second members 12 protrudes outward from the first member 11. Preferably, at each side edge of the first member 11 in the width direction, two or more second members 12 protrude outward from the first member 11 in the width direction. In this embodiment, each of the second members 12 extends in the width direction of the first member 11, and both longitudinal ends of each second member 12 protrude outward from the first member 11 in the width direction.

[0035] The first member 11 and the second member 12 are each formed from a metal plate. Preferably, the first member 11 and the second member 12 are each formed from a steel plate. More preferably, the first member 11 and the second member 12 are formed from a zinc-plated steel plate or an aluminum-plated steel plate. The material of the first member 11 may be the same as or different from the material of the second member 12.

[0036] Figure 2 is a cross-sectional view of the cooling member 10 shown in Figure 1, along line II-II. In Figure 2, a cross-section (transverse plane) of the cooling member 10 perpendicular to the longitudinal direction of the second member 12 is shown.

[0037] Referring to Figure 2, in this embodiment, the main body portion 121 of each second member 12 has a substantially rectangular shape in cross-sectional view of the cooling member 10. More specifically, the main body portion 121 includes a top plate 121a, a pair of ridge portions 121b, and a pair of vertical walls 121c.

[0038] The top plate 121a faces the first member 11 with a gap between them. In a cross-sectional view of the cooling member 10, the ridge portion 121b is provided continuously on both sides of the top plate 121a. The vertical walls 121c are continuous with the ridge portion 121b on the opposite side of the top plate 121a. In a cross-sectional view of the cooling member 10, the vertical walls 121c extend from the ridge portion 121b toward the first member 11.

[0039] The top plate 121a and the vertical wall 121c may each have a substantially straight shape in a cross-sectional view of the cooling member 10. The ridge portion 121b may each have a substantially arc shape in a cross-sectional view of the cooling member 10. The ridge portion 121b is the corner portion between the top plate 121a and the vertical wall 121c.

[0040] Multiple second members 12, together with the first member 11, form multiple refrigerant flow paths 13. More specifically, the refrigerant flow paths 13 are defined by the main body portion 121 of each second member 12 and the first member 11. When used as a cooling member, liquid refrigerant is supplied to each of the refrigerant flow paths 13. The refrigerant is not particularly limited, but may be, for example, water or LLC (Long Life Coolant). A header (not shown) for supplying or discharging refrigerant may be attached to the longitudinal end of the second member 12.

[0041] In each second member 12, the flange portion 122 is joined to the first member 11. The flange portion 122 is joined to the first member 11 in a manner that ensures the liquid-tightness of the refrigerant flow path 13. The flange portion 122 is joined to the first member 11 by, for example, laser welding or brazing. The flange portion 122 may also be joined to the first member 11 by adhesive (sealer), or by a combination of adhesive and spot welding.

[0042] The flange portion 122 has a width W1. The width W1 is the length of the surface of the flange portion 122 that is in contact with the first member 11 in a cross-sectional view of the second member 12. The width W1 is preferably as narrow as possible while ensuring the joint between the flange portion 122 and the first member 11, for example, 25.0 mm or less, preferably 22.0 mm or less, and more preferably 20.0 mm or less. The width W1 may be 10.0 mm or more. The width W1 of the flange portion 122 in each second member 12 is preferably the same as the width W1 of the flange portion 122 in other second members 12, but it may be different.

[0043] Each of the refrigerant flow paths 13 has a depth D1. The depth D1 is the maximum distance in the thickness direction of the first member 11 from the surface 111 of the first member 11 to the outer surface of each second member 12. The depth D1 is, for example, 2.0 mm or more, preferably 5.0 mm or more, and more preferably 7.0 mm or more. The depth D1 may be 13.0 mm or less. The depth D1 of each refrigerant flow path 13 is preferably the same as the depth D1 of the other refrigerant flow paths 13, but they may be different.

[0044] [Mold] Figures 3A and 3B are perspective views showing the schematic configuration of the mold 20 according to this embodiment. Figure 3A shows the mold 20 viewed from a diagonal downward side, and Figure 3B shows the mold 20 viewed from a diagonal upward side. The cooling member 10 (Figures 1 and 2) can be manufactured using the mold 20.

[0045] Referring to Figures 3A and 3B, the die 20 comprises a first die 21 and a second die 22. The first die 21 and the second die 22 are a pair of dies. The die 20 is used, for example, by being mounted on a known press device, so that the first die 21 and the second die 22 can move closer to and further apart from each other. Hereinafter, the direction in which the first die 21 and the second die 22 move closer to and further apart from each other will be referred to as the processing direction D. The processing direction D is, for example, the vertical direction.

[0046] In this embodiment, the second mold 22 is positioned above the first mold 21. Referring to Figure 3A, the second mold 22 includes a plurality of molding surfaces 221 and a flange surface 222. The molding surfaces 221 and the flange surface 222 are provided on the surface of the second mold 22 that faces the processing direction D relative to the first mold 21.

[0047] Each of the molding surfaces 221 is primarily a surface for forming the main body portion 121 of the second member 12 (Figures 1 and 2). Each molding surface 221 has a concave shape relative to the flange surface 222. The molding surfaces 221 correspond to the main body portion 121 of the second member 12 and extend straight along the processing direction D. Each of the molding surfaces 221 is configured to form a hollow space together with the first mold 21.

[0048] The flange surface 222 is configured to clamp the material, which will be described later, together with the first mold 21. The flange surface 222 includes an outer periphery 222a and an interior 222b. The outer periphery 222a is the part of the flange surface 222 that surrounds a plurality of forming surfaces 221 when viewed along the machining direction D. The interior 222b is located inside the outer periphery 222a when viewed along the machining direction D. The interior 222b is the part of the flange surface 222 that is located between adjacent forming surfaces 221.

[0049] Referring to Figures 3A and 3B, a projection 23 may be formed on one of the first mold 21 and the second mold 22. In this embodiment, a projection 23 is formed on the first mold 21. In this embodiment, a plurality of projections 23 are formed on the first mold 21. Each projection 23 is positioned on the portion of the first mold 21 that faces the flange surface 222 of the second mold 22. More specifically, the projections 23 are provided on the first mold 21 such that when the first mold 21 and the second mold 22 are closed, the projections 23 are positioned on both sides in the longitudinal direction of each molding surface 221 of the second mold 22.

[0050] Each of the projections 23 has, for example, a circular shape when viewed along the machining direction D. However, when viewed along the machining direction D, the projections 23 may have a polygonal shape such as a triangular or quadrilateral shape. If the projections 23 have a shape other than circular, the projections 23 may be formed to be wider on the side closer to each molded surface 221.

[0051] In this embodiment, the mold 20 further includes a convex bead portion 24 and a convex sealing portion 25. The bead portion 24 and the sealing portion 25 are provided in the first mold 21 and the second mold 22, respectively.

[0052] As shown in Figure 3A, in the second mold 22, the bead portion 24 is positioned on the flange surface 222. In the second mold 22, the bead portion 24 is provided on the flange surface 222 so as to substantially surround each of the molding surfaces 221. At least a portion of the bead portion 24 is positioned inside 222b of the flange surface 222. As shown in Figure 3B, in the first mold 21, a bead portion 24 is provided corresponding to the bead portion 24 of the second mold 22. In the first mold 21, the bead portion 24 may surround one or more protrusions 23.

[0053] As shown in Figure 3A, in each of the first mold 21 and the second mold 22, the seal portion 25 is provided so as to substantially surround the bead portion 24. The seal portion 25 may surround the bead portion 24 without interruption around its entire circumference, but it may be interrupted in part, for example, at a position away from the projection portion 23. The seal portion 25 may be interrupted in a range of, for example, 150 mm or less.

[0054] Figure 4 is a partial longitudinal cross-sectional view of the mold 20 at the location of the projection 23. The longitudinal cross-section of the mold 20 refers to the cross-section along the longitudinal direction of the molding surface 221 of the second mold 22.

[0055] Referring to Figure 4, the projection 23 includes a tip surface 231 and a side surface 232. The tip surface 231 is the surface of the projection 23 that is located closest to the second mold 22. In this embodiment, the tip surface 231 is a flat surface substantially perpendicular to the machining direction D.

[0056] The side surface 232 is provided continuously with respect to the tip surface 231. In this embodiment, when viewed in a cross-section including the central axis of the projection 23, the side surface 232 is inclined with respect to the machining direction D such that the width of the projection 23 is larger at the base end and smaller at the tip end.

[0057] Figure 5 shows another example of the projection 23. In the example in Figure 4, the side surface 232 of the projection 23 is an inclined surface that is inclined overall with respect to the machining direction D, but in the example in Figure 5, a step is provided on the side surface 232 at the base end of the projection 23. That is, when viewed in a cross-section including the central axis of the projection 23, the portion 232a of the side surface 232 at the base end of the projection 23 is substantially parallel to the machining direction D. Therefore, the width of the projection 23 is substantially constant at the base end. Other parts of the side surface 232 may be inclined with respect to the machining direction D, as in Figure 4.

[0058] Referring to Figures 4 and 5, a fluid is used in the manufacture of the cooling member 10 (Figures 1 and 2). Therefore, at least one of the first mold 21 and the second mold 22 is provided with a fluid supply passage 26 for supplying fluid to the hollow space. In this embodiment, the fluid supply passage 26 is provided in the first mold 21. One end of the fluid supply passage 26 opens to a projection 23. The fluid supply passage 26 is connected to a fluid supply source (not shown) provided outside the first mold 21.

[0059] Although not shown in the diagram, the first mold 21 may be provided with multiple fluid supply passages 26 corresponding to multiple protrusions 23. The other end of each fluid supply passage 26 can open, for example, on the side of the first mold 21. Alternatively, multiple fluid supply passages 26 may be consolidated into a single system within the first mold 21 and then open on the back of the first mold 21 or the like.

[0060] As shown in Figures 4 and 5, the fluid supply passage 26 can open on the side surface 232 of the projection 23. Preferably, the fluid supply passage 26 opens on the tip side of the projection 23. In the examples in Figures 4 and 5, the portion of the fluid supply passage 26 that passes through the projection 23 is substantially parallel to the machining direction D. However, at least the portion of the fluid supply passage 26 that passes through the projection 23 may be inclined with respect to the machining direction D. The fluid supply passage 26 can be inclined with respect to the machining direction D so as to intersect the side surface 232 of the projection 23 when viewed in a cross-section including the central axis of the projection 23. At least the portion of the fluid supply passage 26 that passes through the projection 23 may be inclined at an angle greater than 0° and less than or equal to 60° with respect to the machining direction D when viewed in a cross-section including the central axis of the projection 23.

[0061] Near the projection 23, a relief portion 222c may be formed on the flange surface 222 of the second mold 22. Viewed in a cross-section including the central axis of the projection 23, the relief portion 222c extends, for example, from the portion of the flange surface 222 facing the tip surface 231 of the projection 23 to the molding surface 221 (Figure 3A). The relief portion 222c has a concave shape relative to the rest of the flange surface 222.

[0062] Figure 6 is a partial cross-sectional view of the mold 20 at the position of the molding surface 221 of the second mold 22. The cross-section of the mold 20 refers to the cross-section perpendicular to the longitudinal direction of the molding surface 221.

[0063] As shown in Figure 6, in the second mold 22, the outer periphery 222a of the flange surface 222 has a width W31. The interior 222b of the flange surface 222 has a width W32. The width W31 is the length of the outer periphery 222a in the cross-section of the mold 20. The width W32 is the length of the interior 222b in the cross-section of the mold 20. The width W32 is smaller than the width W31. The width W32 is, for example, 10.0 mm or less, preferably 5.0 mm or less, and more preferably 3.0 mm or less. The width W32 may be, for example, 1.0 mm or more. Although not particularly limited, the width W31 is 0.5 mm or more larger than the width W32.

[0064] In the second mold 22, it is preferable that the bead portion 24 on the interior 222b of the flange surface 222 has a shape that allows surface contact with the first mold 21 or its bead portion 24. Each of the bead portions 24 may have, for example, a substantially rectangular cross-section. The width of each bead portion 24 may be 1.0 mm or more, and preferably 2.0 mm or more. The width of each bead portion 24 is preferably 5.0 mm or less, and more preferably 3.0 mm or less. The height of each bead portion 24 is, for example, 0.2 mm or more. The height of each bead portion 24 may be 0.5 mm or less. The bead portion 24 is made of, for example, metal. The bead portion 24 may be integrally formed with the first mold 21 or the second mold 22.

[0065] In the second mold 22, the seal portion 25 on the outer periphery 222a of the flange surface 222 may have a rectangular cross-section, similar to the bead portion 24. The seal portion 25 of the first mold 21 may also have a rectangular cross-section. The width of each seal portion 25 may be 1.0 mm or more, and preferably 2.0 mm or more. The width of each seal portion 25 is preferably 5.0 mm or less, and more preferably 3.0 mm or less. However, it is preferable that the width of the bead portion 24 is smaller than the width of the seal portion 25. The height of each seal portion 25 is, for example, 0.2 mm or more. The height of each seal portion 25 may be 0.5 mm or less. The seal portion 25 may be made of metal, but may also be made of an elastic material such as resin.

[0066] [Method for manufacturing structural members] Next, a method for manufacturing the cooling member 10 using the mold 20 will be described with reference to Figures 7A to 7G. The method for manufacturing the cooling member 10 according to this embodiment comprises a preparation step and a molding step. The method for manufacturing the cooling member 10 may further include a heating step.

[0067] (preparation process) As shown in Figures 7A and 7B, the preparation step involves preparing the material 30. The material 30 includes a first blank 31 and a plurality of second blanks 32.

[0068] The first blank 31 is a blank corresponding to the first member 11 (Figures 1 and 2). In this embodiment, the first blank 31 has a plurality of through holes 33. The through holes 33 are provided, for example, corresponding to the projections 23 (Figure 3B) of the first mold 21.

[0069] The second blanks 32 are blanks corresponding to the second members 12 (Figures 1 and 2). The second blanks 32 are superimposed on the first blanks 31. The second blanks 32 are superimposed on the first blanks 31 so as to cover each through hole 33. The second blanks 32 are joined to the first blanks 31.

[0070] In this embodiment, each of the second blanks 32 is joined to the first blank 31. The second blanks 32 are joined to the first blank 31, for example, by laser welding or brazing. The second blanks 32 may also be joined to the first blank 31 by adhesive (sealer), or by a combination of adhesive and spot welding. Each second blank 32 is joined to the first blank 31 at least in the portion that becomes the flange portion 122 of the second member 12 (Figures 1 and 2). Each second blank 32 may be joined to the first blank 31 over its entire outer circumference.

[0071] The first blank 31 and the second blank 32 may each be formed from a single metal sheet, or they may each include multiple metal sheets (subblanks). The metal sheet is preferably a steel sheet. The metal sheet is more preferably a zinc-plated steel sheet or an aluminum-plated steel sheet. The material of the first blank 31 may be the same as or different from the material of the second blank 32.

[0072] The first blank 31 may have a tensile strength of, for example, 440 MPa or more. Each of the second blanks 32 may also have a tensile strength of, for example, 440 MPa or more. The first blank 31 and the second blank 32 each preferably have a tensile strength of 590 MPa or more, and more preferably 980 MPa or more. The tensile strength of the first blank 31 may be the same as or different from the tensile strength of the second blank 32. For example, the tensile strength of the first blank 31 may be less than the tensile strength of the second blank 32.

[0073] (Heating process) The heating process is carried out before the forming process. In the heating process, the prepared material 30 is heated. The material 30 is heated, for example, in a heating furnace. The heating temperature of the material 30 is determined according to the material of the first blank 31 and the second blank 32. If the first blank 31 and the second blank 32 are formed from steel sheets, the material 30 is heated to the austenite transformation completion temperature (A) of the first blank 31 and the second blank 32. c3 It is preferable that the material be heated to a temperature of 900°C or higher. If the first blank 31 and the second blank 32 are made of steel plates, the material 30 is heated to, for example, 900°C or higher. However, the heating step is not necessarily required.

[0074] (molding process) As shown in Figures 7C to 7G, the molding process involves molding the cooling member 10 from the material 30. More specifically, using the first mold 21 and the second mold 22, the first member 11 is molded from the first blank 31, and the second member 12 is molded from the second blank 32. The molding of the first member 11 and the second member 12 is carried out, for example, by cold molding. However, the molding of the first member 11 and the second member 12 may also be carried out by hot molding. That is, the molding process may be a cold molding process or a hot molding process (hot stamping). If the molding process is a hot molding process, the cooling member 10 is molded from the heated material 30 during the molding process.

[0075] Figures 7C, 7E, and 7F are cross-sectional views (longitudinal cross-sectional views) of the mold 20 and material 30 cut along the longitudinal direction of the molding surface 221 of the second mold 22, and Figures 7D and 7G are cross-sectional views (horizontal cross-sectional views) of the mold 20 and material 30 cut perpendicular to the longitudinal direction of the molding surface 221 of the second mold 22. Referring to Figures 7C and 7D, in the molding process, first, with the first mold 21 and the second mold 22 separated in the processing direction D, the material 30 is placed between the first mold 21 and the second mold 22. At this time, the material 30 is positioned such that each through hole 33 of the first blank 31 corresponds to the projection 23 of the first mold 21. In this embodiment, since the first mold 21 is positioned below the second mold 22, the material 30 is placed on the first mold 21. Then, the first mold 21 and the second mold 22 are brought relatively close together, and a portion of the material 30 is held between the first mold 21 and the second mold 22.

[0076] When the first mold 21 and the second mold 22 are closed, the area of ​​the material 30 other than the area that will become the main body portion 121 of the second member 12 (Figures 1 and 2) is held between the flange surfaces 222 of the first mold 21 and the second mold 22. At this time, the area of ​​each second blank 32 that will become the flange portion 122 of the second member 12 (Figures 1 and 2) is pressed more strongly by the flange surface 222 compared to the rest of the material 30. More specifically, the portion of the second blank 32 that will become the flange portion 122 (Figures 1 and 2) is pressed and restrained relatively strongly by the interior 222b of the flange surface 222. On the other hand, the outer periphery of the first blank 31 is pressed down by the outer periphery 222a of the flange surface 222.

[0077] As shown in Figures 7E to 7G, in the molding process, the flange surfaces 222 of the first mold 21 and the second mold 22 hold the portions of the first blank 31 and the second blank 32 that will become the flange portion 122 of the second member 12, and fluid is supplied between the first blank 31 and the second blank 32. This fluid causes each of the second blanks 32 to expand in the hollow space formed between the molding surfaces 221 of the first mold 21 and the second mold 22, thereby molding the main body portion 121 of the second member 12. In this embodiment, the molding process includes a first step and a second step.

[0078] Referring to Figure 7E, in the first molding step, the projections 23 provided on the first mold 21 are inserted into each of the through holes 33 of the first blank 31, and the flange surfaces 222 of the first mold 21 and the second mold 22 clamp the flange portion 122 of the second member 12 from each of the first blank 31 and the second blank 32, respectively, creating a gap between the first blank 31 and the second blank 32. The projections 23 are inserted into the through holes 33 of the first blank 31 and lift each second blank 32 from the inside of the material 30, thus creating a gap between the first blank 31 and each second blank 32.

[0079] In this embodiment, since the tip surface 231 of the projection 23 is substantially flat, the projection 23 can make surface contact with the second blank 32 at its tip surface 231. When the first mold 21 and the second mold 22 are closed, the material 30 is first sandwiched between the tip surface 231 of the projection 23 and the relief portion 222c of the flange surface 222 of the second mold 22. This allows the material 30 to be positioned.

[0080] When the first mold 21 and the second mold 22 are closed, the material 30 is held between the bead portion 24 of the first mold 21 and the bead portion 24 of the second mold 22. Also, when the first mold 21 and the second mold 22 are closed, the seal portion 25 of the first mold 21 (Figure 3B) abuts against the seal portion 25 of the second mold 22 (Figure 3A). At the location of the bead portion 24, the material 30 is held more strongly than at other parts of the first mold 21 and the second mold 22.

[0081] Referring to Figures 7F and 7G, in the second molding step, fluid is supplied from the projection 23 into the gap between the first blank 31 and each of the second blanks 32, and this fluid causes each of the second blanks 32 to expand in the hollow space formed by the molding surfaces 221 of the first mold 21 and the second mold 22, thereby forming the main body 121 of the second member 12. The second step is carried out with the material 30 sandwiched between the flange surfaces 222 of the first mold 21 and the second mold 22. The fluid is supplied from a fluid supply source (not shown) to a fluid supply passage 26, passes through the fluid supply passage 26, and flows out from the projection 23 into the hollow space.

[0082] Within the hollow space of the mold 20, each second blank 32 is inflated by the fluid supplied from the projection 23 and then pressed against the molding surface 221 of the second mold 22. This forms a hollow closed cross-section in the material 30. More specifically, a hollow coolant channel 13 is formed from the material 30.

[0083] The fluid used in the molding process is not particularly limited. The fluid may be a liquid such as water, or a gas such as nitrogen gas or compressed air. The fluid may be a liquid or gas under high pressure, for example, 10 MPa or higher. The temperature of the fluid may be appropriately determined according to the material of the material 30, and may be, for example, room temperature.

[0084] The cooling member 10 can be obtained through the process described above. After the molding process, a portion of the cooling member 10 may be removed by laser cutting or the like. For example, at least the portion of the cooling member 10 in which the through hole 33 is provided may be removed after the molding process. Also, the portion of the cooling member 10 corresponding to the relief portion 222c (Figures 4 and 5) of the second mold 22 may be removed after the molding process.

[0085] Figure 8A is a partial cross-sectional view of the cooling member 10 after the molding process, for example, after the removal of the outer periphery, which has resulted in its final shape. Figure 8B is a bottom view of the cooling member 10 in its final shape. As shown in Figures 8A and 8B, the cooling member 10 has multiple refrigerant flow paths 13 formed by the first member 11 and the second member 12. The total area of ​​the region on the surface 111 of the first member 11 where the refrigerant flow paths 13 are provided is 50% or more and less than 90% of the area of ​​the smallest rectangle R1 that circumscribes the multiple second members 12 within the range of the surface 111. Rectangle R1 is the smallest rectangle or square that circumscribes the multiple second members 12 on the projection plane and is located within the first member 11 when the cooling member 10 is projected in a direction corresponding to the downward direction of the vehicle body. In other words, rectangle R1 is the smallest rectangle or square that encloses the portion of the multiple second members 12 that is placed on the first member 11. The area of ​​rectangle R1 corresponds to the area of ​​the cooling member 10 that substantially cools the battery cells. For example, in the example in Figure 8B, the portion of each second member 12 that protrudes from the first member 11 in the vehicle width direction is not included in rectangle R1. Also, the portion of the first member 11 that protrudes from the group of second members 12 in the front-rear direction (vehicle length direction) of the vehicle body is not included in rectangle R1.

[0086] The ratio of the total area of ​​the refrigerant flow path 13 to the area of ​​rectangle R1 can be measured as follows. That is, after removing the cooling member 10 from the vehicle body, a three-dimensional shape measurement of the cooling member 10 is performed. If the first member 11 and the second member 12 were disassembled when removing the cooling member 10 from the vehicle body, the second member 12 is reattached to the first member 11 and then the three-dimensional shape measurement of the cooling member 10 is performed. In the three-dimensional shape measurement, a known or commercially available three-dimensional measuring device is used to measure the thickness of each part from above the cooling member 10, for example. Then, the area of ​​the cooling member 10 in which the measured thickness is substantially equal to the sum of the plate thickness of the first member 11 and the plate thickness of the second member 12 is defined as the area other than the refrigerant flow path 13. The value obtained by subtracting the area of ​​the area other than the refrigerant flow path 13 from the area of ​​rectangle R1 is taken as the total area of ​​the refrigerant flow path 13, and the ratio of the total area of ​​the refrigerant flow path 13 to the area of ​​rectangle R1 can be calculated.

[0087] In the manufacturing method according to this embodiment, each of the second members 12 is formed by fluid-assisted stretch molding (hydraulic or blow molding). By performing hydraulic or blow molding, the thickness of the main body portion 121 of each second member 12 is reduced compared to when each second member 12 is formed by press molding or the like. Specifically, in each of the second members 12, the rate of reduction in thickness of the central part of the main body portion 121, based on the thickness of the flange portion 122, is 5.0% or more. In each of the second members 12, the rate of reduction in thickness of the central part of the main body portion 121, based on the thickness of the flange portion 122, is, for example, 40.0% or less. Depending on the molding conditions of the cooling member 10, it is preferable that the rate of reduction in thickness of the central part of the main body portion 121, based on the thickness of the flange portion 122, is 39.0% or less in order to reduce the possibility of cracking in each second member 12. The central part of the main body 121 is the portion of the main body 121 that is furthest from the first member 11 in the thickness direction, in a cross-section (transverse plane) perpendicular to the longitudinal direction of the second member 12. In this embodiment, when the main body 121 includes a top plate 121a, the central part of the top plate 121a in a cross-sectional view can be considered the central part of the main body 121.

[0088] The thickness of the second member 12 can be measured, for example, as follows: After removing the second member 12 from the vehicle body, the second member 12 is cut perpendicular to its longitudinal direction. The second member 12 is cut at the end in the longitudinal direction where the depth D1 of the refrigerant flow path 13 is maximum. In the resulting cross-section of the second member 12, the thickness t1 of the center of the main body portion 121 is measured. Also, in the same cross-section, the thickness t2 of the portion of the flange portion 122 that is in contact with the first member 11 is measured. The thickness t2 may be measured at a predetermined distance (e.g., 3 mm) away from the free end of the flange portion 122. The thickness t1 of the center of the main body portion 121 and the thickness t2 of the flange portion 122 can be measured, for example, using a micrometer. If the resulting plate thickness t1 of the main body 121 satisfies 0.050 ≤ {(t2-t1) / t2}, then it can be said that the plate thickness reduction rate at the center of the main body 121, based on the plate thickness t2 of the flange portion 122, is 5.0% or more. Also, if the plate thickness t1 of the main body 121 satisfies {(t2-t1) / t2} ≤ 0.400, then the plate thickness reduction rate at the center of the main body 121, based on the plate thickness t2 of the flange portion 122, is 40.0% or less.

[0089] In the flange portion 122 of the second member 12, a reduction in plate thickness is unlikely to occur during the molding process. Therefore, the plate thickness t2 of the flange portion 122 is substantially equal to the plate thickness of the second blank 32 (Figure 7A) in the material 30. The plate thickness t2 of the flange portion 122 is, for example, 1.0 mm or less. The plate thickness t2 may be 0.4 mm or more. The plate thickness of the first member 11 may be the same as or different from the plate thickness of the second member 12. The plate thickness of the first member 11 is, for example, 1.0 mm or less. The plate thickness of the first member 11 may be 0.4 mm or more.

[0090] In the cooling member 10 manufactured by the manufacturing method according to this embodiment, the second member 12 can have a Vickers hardness of 120 HV or more. Preferably, the Vickers hardness of the second member 12 is 150 HV or more. If the cooling member 10 is manufactured by hot forming (hot stamping), the second member 12 can have a Vickers hardness of 300 HV or more.

[0091] The Vickers hardness of the second member 12 can be measured by the Vickers hardness test specified in JIS Z 2244-1:2024. Specifically, after removing the second member 12 from the vehicle body, a test piece is obtained by cutting the main body 121 of the second member 12 perpendicular to its longitudinal direction using laser cutting or the like. The second member 12 is cut at the end in the longitudinal direction where the depth D1 of the refrigerant flow path 13 is maximum. The test piece is then embedded in resin so that the cross-section of the second member 12 is positioned on the surface, and the cross-section is polished. Subsequently, the Vickers hardness of the center of the main body 121 is measured at a position 1 / 4 of the plate thickness from the surface of the second member 12 with a test force of 0.49 N. The measured Vickers hardness can be taken as the Vickers hardness HV1 of the main body 121. In addition, the Vickers hardness of the flange portion 122 is measured at a position 1 / 4 of the plate thickness from the surface of the second member 12. The Vickers hardness may be measured at a predetermined distance (e.g., 3 mm) away from the free end of the flange portion 122. The measured Vickers hardness can be taken as the Vickers hardness HV2 of the flange portion 122.

[0092] The Vickers hardness HV1 measured at the center of the main body 121 is, for example, 105% or more of the Vickers hardness HV2 measured at the flange portion 122. Preferably, the Vickers hardness HV1 of the main body 121 is 110% or more of the Vickers hardness HV2 of the flange portion 122. For example, the Vickers hardness HV1 of the main body 121 is 130% or less of the Vickers hardness HV2 of the flange portion 122. The Vickers hardness HV1 and HV2 may each be 120 HV or more, or 150 HV or more. If the cooling member 10 is manufactured by hot forming (hot stamping), the Vickers hardness HV1 and HV2 may each be 300 HV or more.

[0093] The first member 11 may also have a Vickers hardness of 120 HV or higher. The Vickers hardness of the first member 11 is preferably 150 HV or higher, and more preferably 300 HV or higher. The Vickers hardness of the first member 11 can be measured in the same manner as the Vickers hardness of the second member 12. However, when measuring the Vickers hardness of the first member 11, the test piece for the Vickers hardness test can be obtained at any position on the first member 11.

[0094] [effect] In this embodiment, a cooling member 10 is manufactured by integrating a plate-shaped first member 11 with a plurality of second members 12 that form a refrigerant flow path 13 together with the first member 11. More specifically, the first member 11 is formed from a first blank 31 by a first mold 21 and a second mold 22, and the second members 12 are formed from a plurality of second blanks 32. In the molding process, the flange surfaces 222 of the first mold 21 and the second mold 22 hold the portion of each of the first blank 31 and the second blank 32 that will become the flange portion 122 of the second member 12, and fluid is supplied between the first blank 31 and the second blank 32, causing each of the second blanks 32 to expand in the hollow space of the mold 20. As a result, the first mold 21 forms the first member 11 from the first blank 31, and within each hollow space, the second blank 32 is pressed against the molding surface 221 of the second mold 22 to form the main body 121 of the second member 12. The main body 121 of the second member 12, together with the first member 11, forms a hollow closed cross-section whose interior becomes a refrigerant flow path 13.

[0095] In this embodiment, by utilizing a fluid, the first member 11 and the second member 12 can be integrated from the material 30 stage, and a cooling member 10 having a hollow cross-section can be molded in this integrated state. In other words, a cooling member 10 can be manufactured as an integrated component having a hollow cross-section.

[0096] In this embodiment, a projection 23 is formed on the portion of the first mold 21 that corresponds to the flange surface 222 of the second mold 22. Therefore, when the first mold 21 and the second mold 22 are closed with the projection 23 inserted into the through hole 33 of the first blank 31, and the flange surfaces 222 of the first mold 21 and the second mold 22 clamp the first blank 31 and the portions of each second blank 32 that will become the flange portion 122, the projection 23 lifts each second blank 32, creating a gap between the first blank 31 and each second blank 32. In other words, a gap that serves as a fluid passage is naturally formed simply by closing the first mold 21 and the second mold 22. Therefore, there is no need to separately perform preforming to secure a fluid passage. As a result, the cooling member 10 as an integrated part having a hollow cross-section can be manufactured with high productivity.

[0097] In this embodiment, a bead portion 24 is provided in each of the first mold 21 and the second mold 22. The bead portion 24 is provided in each of the first mold 21 and the second mold 22 so as to surround the hollow space of the mold 20 when the first mold 21 and the second mold 22 are closed. This improves the liquid-tightness or airtightness of the hollow space of the mold 20. Specifically, when the first mold 21 and the second mold 22 are closed, the bead portion 24 of the first mold 21 and the bead portion 24 of the second mold 22 strongly abut and clamp the first blank 31 and the second blank 32, making it difficult for fluid to leak from between the first blank 31 and the second blank 32. Therefore, the molding of the cooling member 10 using fluid can be performed more effectively.

[0098] In this embodiment, a sealing portion 25 is further provided in each of the first mold 21 and the second mold 22. Each sealing portion 25 is positioned to surround the bead portion 24. When the first mold 21 and the second mold 22 are closed, the sealing portion 25 can seal the material 30 in the mold 20. As a result, fluid leakage to the outside of the mold 20 is reduced, and the molding of the cooling member 10 using fluid can be performed even more effectively.

[0099] In this embodiment, the projection 23 provided on the first mold 21 may have a step on its side surface 232. That is, the base end portion 232a of the side surface 232 of the projection 23 may be substantially parallel to the processing direction D in a longitudinal cross-sectional view of the mold 20. In this case, it is preferable that the size of the portion 232a is greater than or equal to the size of the through hole 33 of the first blank 31. As a result, when the projection 23 is inserted into the through hole 33 of the first blank 31, the through hole 33 is widened by the portion 232a. Consequently, the periphery of the through hole 33 is in strong contact with the side surface 232 of the projection 23 over its entire circumference, making it difficult for a gap to form between the periphery of the through hole 33 and the projection 23. Therefore, it becomes difficult for fluid from the projection 23 to enter between the first blank 31 and the first mold 21. Consequently, fluid is supplied more reliably between the first blank 31 and the second blank 32, and the molding of the cooling member 10 can be performed more effectively.

[0100] In this embodiment, it is preferable that the fluid supply passage 26 formed in the first mold 21 opens at a position near the tip of the projection 23. Furthermore, it is preferable that at least the portion of the fluid supply passage 26 that passes through the projection 23 is inclined with respect to the processing direction D so as to intersect with the side surface 232 of the projection 23. This makes it difficult for fluid from the projection 23 to enter between the first blank 31 and the first mold 21, and facilitates the supply of fluid between the first blank 31 and the second blank 32. Therefore, the molding of the material 30 using fluid can be performed more effectively.

[0101] In this embodiment, a cooling member 10 having a hollow cross-section is formed by expanding the material 30 with a fluid. In this case, the second member 12 of the cooling member 10 has a different plate thickness distribution than when it is manufactured by general press forming. For example, when the second member 12 is manufactured by general press forming, a local reduction in plate thickness occurs at the position of the ridge portion 121b of the main body portion 121. On the other hand, when the main body portion 121 of the second member 12 is formed by expanding the second blank 32 with a fluid as in this embodiment, the plate thickness of the central part of the main body portion 121 decreases. Specifically, in each of the second member 12, the rate of reduction in plate thickness at the center of the main body portion 121, based on the plate thickness t2 of the flange portion 122, is 5.0% or more. In this way, by reducing the plate thickness at the center of the main body portion 121 in each second member 12 during the molding process, heat transfer between the refrigerant and each second member 12 becomes easier, and the cooling performance of each second member 12 can be improved. Furthermore, when the cooling member 10 is manufactured by cold forming, work hardening occurs in each second member 12 from the top plate 121a to the ridge portion 121b, giving the second member 12 high strength. When the cooling member 10 is manufactured by hot forming (hot stamping), the thickness of the top plate 121a decreases, making it easier for the top plate 121a to cool during the forming process, and thus increasing the hardness of the top plate 121a. As a result, the main body portion 121 of the second member 12 can be given high strength.

[0102] In the cooling member 10 according to this embodiment, each of the second members 12 protrudes from the first member 11 in the width direction. More specifically, both ends of each second member 12 protrude outward from the first member 11 in the width direction. Therefore, when a collision load is applied to the cooling member 10 from the width direction (vehicle width direction) of the first member 11, each second member 12 can support the collision load and absorb the collision energy. For example, when the cooling member 10 is subjected to a collision load, the second members 12 that protrude from the first member 11 in the width direction can preferentially deform and absorb the collision energy. Therefore, the cooling member 10 can be given not only a cooling function for battery cells but also collision resistance. In this embodiment, since the main body portion 121 of each second member 12 has high strength due to work hardening, the cooling member 10 can exhibit better collision resistance.

[0103] When the cooling member 10 is molded using a fluid as in this embodiment, the central part of the main body 121 of each second member 12 becomes harder compared to the flange portion 122. More specifically, at the longitudinal end of each second member 12, where the depth D1 (molding height) of the refrigerant flow path 13 is maximum, the Vickers hardness HV1 of the central part of the main body 121 increases to 105% or more of the Vickers hardness HV2 of the flange portion 122. Because the main body 121 is harder at the ends of each second member 12, the impact load can be better supported by each second member 12, thereby improving the impact resistance performance of the cooling member 10.

[0104] The cooling member 10 according to this embodiment is attached, for example, to the bottom plate of the battery case of the battery unit. Alternatively, the first member 11 of the cooling member 10 itself may be the bottom plate of the battery case of the battery unit. In the cooling member 10, the total area of ​​the region on the surface 111 of the first member 11 where the refrigerant flow path 13 is provided is 50% or more and less than 90% of the area of ​​the smallest rectangle R1 that circumscribes the plurality of second members 12 within the range of the surface 111. This ensures the cooling efficiency of the battery cells by the cooling member 10.

[0105] In the cooling member 10 according to this embodiment, the width W1 of the flange portion 122 of each second member 12 is preferably 25.0 mm or less. More preferably, the width W1 of the flange portion 122 is 22.0 mm or less, and even more preferably 20.0 mm or less. By reducing the width W1 of the flange portion 122 of each second member 12 in this way, a larger area occupied by the refrigerant flow path 13 on the surface 111 of the first member 11 can be secured. Therefore, the cooling efficiency of the battery cell by the cooling member 10 can be more easily ensured.

[0106] When manufacturing cooling components using conventional cold press forming, it is difficult to form deep refrigerant channels. Furthermore, for general cooling components, it is sufficient if the refrigerant channels can cool the battery cells. Therefore, in general cooling components, the depth of the refrigerant channels is approximately 2.0 mm to 3.0 mm. On the other hand, in this embodiment, since the main body portion 121 of the second component 12 is formed using fluid, even with cold forming, it is possible to form deeper refrigerant channels 13 compared to the case of conventional cold press forming. The cooling component 10 according to this embodiment has not only cooling performance but also impact resistance performance, so the depth D1 of each refrigerant channel 13 is relatively large. In other words, the height of the main body portion 121 of the second component 12 from the surface 111 of the first component 11 is relatively large. The depth D1 of each refrigerant channel 13 is, for example, 2.0 mm or more, preferably 5.0 mm or more, and more preferably 7.0 mm or more. This makes it easier for each second component 12 to support impact loads, and the impact resistance performance of the cooling component 10 can be further improved.

[0107] <Second Embodiment> Figure 9 is a bottom view of the cooling member 10A according to the second embodiment. The cooling member 10A according to this embodiment includes a first member 11 and a plurality of second members 12A. Figure 9 shows the cooling member 10A as seen from the second member 12A side.

[0108] The cooling member 10A according to this embodiment differs from the cooling member 10 according to the first embodiment in the configuration of the second member 12A. Specifically, in the first embodiment, each of the second members 12 extends substantially straight in the width direction of the first member 11. On the other hand, in this embodiment, each of the second members 12A is folded back at least once near the width edge of the first member 11 so as to traverse the first member 11 multiple times in the width direction.

[0109] Similar to the first embodiment, both longitudinal ends of each second member 12A protrude from the first member 11 in the width direction of the first member 11. Each second member 12A includes a main body portion 121 and a flange portion 122, similar to the first embodiment. The cooling member 10A has the same configuration as the cooling member 10 according to the first embodiment, except that each second member 12A has a folded shape.

[0110] The cooling member 10A according to this embodiment can be manufactured using the same manufacturing method as in the first embodiment. That is, as shown in Figures 10A and 10B, a material 30A is prepared, which includes a first blank 31 and a second blank 32A corresponding to the second member 12A, and the cooling member 10A (Figure 9) is molded from the material 30A using the same molding process as in the first embodiment. In the mold 20 used in the molding process (Figures 3A and 3B), it is sufficient that the molding surface 221 and flange surface 222 of the second mold 22 are configured to correspond to the second member 12A of this embodiment.

[0111] <Third Embodiment> Figure 11 is a bottom view of the cooling member 10B according to the third embodiment. The cooling member 10B according to this embodiment includes a first member 11 and a plurality of second members 12Ba, 12Bb, respectively. Figure 11 shows the cooling member 10B as seen from the second members 12Ba, 12Bb side.

[0112] The cooling member 10B according to this embodiment differs from the cooling member 10 according to the first embodiment in the configuration of the second members 12Ba and 12Bb. Specifically, in the first embodiment, multiple second members 12 had the same shape, whereas in this embodiment, the second member 12Ba and the second member 12Bb have different shapes.

[0113] As shown in Figure 11, the second member 12Ba extends in a direction intersecting the width direction of the first member 11 when viewed from below the cooling member 10B. The second member 12Ba may also extend in a direction substantially perpendicular to the width direction of the first member 11 when viewed from below the cooling member 10B. In other words, each of the second members 12Ba may extend in the longitudinal direction (vehicle length direction) when the cooling member 10B is attached to the vehicle body.

[0114] The second member 12Bb is positioned on both sides of the second member 12Ba in the width direction of the first member 11. In this embodiment, each of the second members 12Bb is folded back at least once near the widthwise edge of the first member 11 so that multiple portions are formed that extend in the width direction of the first member 11. The ends of each second member 12Bb protrude from the first member 11 in the width direction of the first member 11.

[0115] Each of the second members 12Ba and 12Bb includes a main body portion 121 and a flange portion 122 similar to those in the first embodiment. The cooling member 10B can have the same configuration as the cooling member 10 according to the first embodiment, except for the shape of the second members 12Ba and 12Bb when viewed from below.

[0116] The cooling member 10B according to this embodiment can be manufactured using the same manufacturing method as in the first embodiment. That is, as shown in Figures 12A and 12B, a material 30B is prepared including a first blank 31 and second blanks 32Ba and 32Bb corresponding to the second members 12Ba and 12Bb (Figure 11), and the cooling member 10B is molded from the material 30B using the same molding process as in the first embodiment. The mold 20 used in the molding process (Figures 3A and 3B) only needs to be configured such that the molding surface 221 and flange surface 222 of the second mold 22 correspond to the second members 12Ba and 12Bb of this embodiment.

[0117] <Fourth Embodiment> Figure 13 is a perspective view of the cooling member 10C according to the fourth embodiment. The cooling member 10C according to this embodiment can have the same configuration as the cooling member 10 according to the first embodiment. However, in the first embodiment, the multiple second members 12 were separate, whereas in this embodiment, the multiple second members 12C are integrated.

[0118] Figure 14 is a cross-sectional view (cross-section) of the cooling member 10C shown in Figure 13, from line XIV to XIV. Referring to Figure 14, each of the second members 12C includes a main body portion 121 and a flange portion 122 similar to those in the first embodiment. However, the flange portion 122 of each second member 12C is continuous with the flange portion 122 of the adjacent second member 12C. That is, multiple second members 12C are formed from a common metal plate. Alternatively, the flange portion 122 of each second member 12C may be joined with the flange portion 122 of the adjacent second member 12C. Hereinafter, multiple second members 12C may be collectively referred to as a second member unit 120.

[0119] The second member unit 120 is joined to the first member 11. In the second member unit 120, it is preferable that the flange portion 122 located between adjacent second members 12C is joined to the first member 11. The method for joining the second member unit 120 and the first member 11 can be the one exemplified in the first embodiment.

[0120] The cooling member 10C according to this embodiment can be manufactured using the same manufacturing method as in the first embodiment. That is, as shown in Figures 15A and 15B, a material 30C is prepared that includes a first blank 31 and a second blank 32C corresponding to the second member 12C, and the cooling member 10C is molded from the material 30C using the same molding process as in the first embodiment. In this embodiment, corresponding to the integration of multiple second members 12C, multiple second blanks 32C are also integrated in the material 30C to constitute a plate material 320. As shown by the dashed line in Figure 15B, the plate material 320 includes multiple regions corresponding to the second member 12C, and these regions can be considered as second blanks 32C. The plate material 320 is joined to the first blank 31 at least on its outer periphery. Preferably, the boundary portions of adjacent second blanks 32Cs in the plate material 320 are also joined to the first blank 31. In the molding process, the same mold 20 as in the first embodiment can be used.

[0121] In this embodiment, all second members 12C provided on the surface 111 of the first member 11 are integrated. However, only some of the second members 12C provided on the surface 111 of the first member 11 may be integrated. Although not shown, in the cooling member 10A according to the second embodiment, some or all of the second members 12A may be integrated. Similarly, in the cooling member 10B according to the third embodiment, some or all of the second members 12Ba, 12Bb may be integrated. For example, in the cooling member 10B, a plurality of second members 12Ba extending in the vehicle length direction may be integrated in the same way as the second members 12C in this embodiment.

[0122] While embodiments relating to this disclosure have been described above, this disclosure is not limited to the embodiments described above, and various modifications are possible as long as they do not deviate from its spirit.

[0123] In the embodiments described above, examples were given in which projections 23 for securing fluid passages are provided on the first mold 21. However, the projections 23 may also be provided on the flange surface 222 of the second mold 22. The projections 23 only need to be provided on either the flange surface 222 of the first mold 21 or the second mold 22 in a position that allows fluid to be supplied to each hollow space. When the projections 23 are provided on the second mold 22, the through holes 33 for the projections 23 are located in the second blanks 32, 32A, 32Ba, 32Bb, and 32C, respectively, in the materials 30, 30A, 30B, and 30C.

[0124] In the embodiments described above, an example was described in which the first mold 21 is positioned below the second mold 22. However, the positional relationship between the first mold 21 and the second mold 22 is not limited to this. When manufacturing the cooling members 10, 10A, 10B, and 10C, the first mold 21 may be positioned above the second mold 22, for example. The projection 23 may be provided on the mold positioned below the first mold 21 and the second mold 22, or on the mold positioned above. When the projection 23 is provided on the mold positioned above the first mold 21 and the second mold 22, the materials 30, 30A, 30B, and 30C are not placed on the projection 23 during the molding process, so the materials 30, 30A, 30B, and 30C can be stably positioned before the molds of the first mold 21 and the second mold 22 are closed. Therefore, it is not necessary to provide a flat tip surface 231 on the projection 23 for positioning the materials 30, 30A, 30B, and 30C.

[0125] In each of the above embodiments, a convex bead portion 24 is provided on both the first mold 21 and the second mold 22. However, a bead portion 24 does not have to be provided on either the first mold 21 or the second mold 22. However, from the viewpoint of preventing fluid leakage from the refrigerant flow path 13, it is preferable that a bead portion 24 is provided on both the first mold 21 and the second mold 22.

[0126] In each of the above embodiments, a convex sealing portion 25 is provided on both the first mold 21 and the second mold 22. However, the sealing portion 25 may not be provided on one or both of the first mold 21 and the second mold 22. If the sealing portion 25 is provided on the first mold 21 and / or the second mold 22, the sealing portion 25 may be a resin packing such as an O-ring. In this case, the mold having the sealing portion 25 among the first mold 21 and the second mold 22 has a groove formed for arranging the sealing portion 25.

[0127] In each of the above embodiments, a gap is created between the first blank 31 and each of the second blanks 32 by the projection 23 provided on the mold 20, thereby securing a passage for fluid. However, the mold 20 does not necessarily have to be provided with the projection 23. In the molding process, the first blank 31 and the portion of each of the second blanks 32 that will become the flange portion 122 are sandwiched between the flange surfaces 222 of the first mold 21 and the second mold 22, and fluid is supplied between the first blank 31 and the second blanks 32. This fluid causes each of the second blanks 32 to expand in the hollow space of the mold 20, thereby forming the main body portion 121. For example, fluid can also be supplied into the hollow space at the position of the molding surface 221 that forms the hollow space in the mold 20. In this case, the through hole 33 after the molding process can also be used as a supply port or discharge port for refrigerant. When the through-hole 33 is used as a supply or discharge port for refrigerant, the ends of the second members 12, 12A, 12Ba, 12Bb, and 12C must not be cut after the molding process, and the second members 12, 12A, 12Ba, 12Bb, and 12C and the first member 11 must be kept closed.

[0128] In each of the above embodiments, the main body portion 121 of each of the second members 12, 12A, 12Ba, 12Bb, and 12C has a substantially rectangular cross-section. However, the shape of the cross-section of the main body portion 121 is not limited to this. For example, the main body portion 121 may also have a substantially arc-shaped cross-section. [Examples]

[0129] The present disclosure will be further described below with reference to examples. However, the present disclosure is not limited to the following examples.

[0130] To confirm the effects of this disclosure, an analysis was performed using commercially available analysis software (LS-DYNA, manufactured by Livermore Software Technology Corporation) to form the second member 12 described in the first embodiment above. In this analysis, one of the materials (steel plates) shown in Table 1 was used for the second member 12, and the relationship between the forming height of the second member 12 and the plate thickness reduction rate was investigated. The forming height of the second member 12 corresponds to the depth D1 of the refrigerant flow path 13 formed by the second member 12 together with the first member 11.

[0131] [Table 1]

[0132] The conditions and results for each example and comparative example are shown in Table 2.

[0133] [Table 2]

[0134] Examples 1 to 7 and the Reference Example in Table 2 show the first member 11 and the second member 12 being blow-molded integrally using the manufacturing method described in the first embodiment above. Examples 1 to 3, 6, and 7 and the Reference Example assume hot forming (hot stamping), while Examples 4 and 5 assume cold forming. Comparative Examples 1 to 5 show the second member 12 being molded by conventional press forming (hot stamping) without the use of fluid.

[0135] In this analysis, a crack was determined to have occurred in the second member 12 if the maximum thickness reduction rate of the second member 12, based on the material, was 39.0% or more, and no crack was determined to have occurred in the second member 12 if the maximum thickness reduction rate was less than 39.0%. As can be seen from Examples 1 to 7 and the Reference Example, when the first member 11 and the second member 12 were blow-molded integrally, with the shape of the second member 12 in this analysis, no crack occurred in the second member 12 until the depth D1 of the refrigerant flow path 13 reached 15.0 mm. In contrast, as can be seen from Comparative Examples 1 to 5, when the second member 12 was molded by conventional press molding, a crack occurred in the second member 12 when the depth D1 of the refrigerant flow path 13 reached 7.0 mm. Therefore, according to the manufacturing method of this disclosure, the first member 11 and the second member 12, which form a refrigerant flow path 13 with a relatively large depth D1, can be molded integrally while suppressing cracking of the second member 12.

[0136] For each of Examples 1-7, the Reference Example, and Comparative Examples 1-5, the rate of thickness reduction at the center of the main body portion 121 (center of the top plate 121a) relative to the material thickness was measured at the longitudinal end of the second member 12 where the depth D1 of the refrigerant flow path 13 is maximum, using the measurement method described in the First Embodiment. Since there is virtually no reduction in thickness at the flange portion 122 of the second member 12 during molding, the material thickness corresponds to the thickness of the flange portion 122. As shown in Table 2, in Examples 1-7, the rate of thickness reduction at the center of the main body portion 121 of the second member 12 was 5.0% or more. On the other hand, in Comparative Examples 1-5, the rate of thickness reduction at the center of the main body portion 121 of the second member 12 was less than 2.0%. Therefore, it can be seen that, according to the manufacturing method of this disclosure, the thickness of the main body portion 121 (top plate 121a) of the second member 12 is reduced during molding.

[0137] Comparing Example 3 and Comparative Example 4, both of which have the same depth D1 of the refrigerant flow path 13 and the same material, the maximum plate thickness reduction rate of the second member 12 in Example 3 is significantly smaller than that in Comparative Example 4. This is because in Example 3, plate thickness reduction occurred in the main body portion 121, and the strain was widely distributed in the main body portion 121. Thus, according to the manufacturing method of this disclosure, the maximum plate thickness reduction rate of the second member 12 can be suppressed as a result of the wide distribution of strain in the main body portion 121.

[0138] Table 2 shows the Vickers hardness HV1 of the central part of the main body portion 121 (the central part of the top plate 121a) and the Vickers hardness HV2 of the flange portion 122 for Examples 3 to 6 and Comparative Example 4, in which the depth D1 of the refrigerant flow path 13 is 10.0 mm. The Vickers hardness HV1 of the main body portion 121 was measured in a cross-section at the longitudinal end of the second member 12, where the main body portion 121 has a molding height of 10.0 mm, using the measurement method described in the first embodiment. The Vickers hardness HV2 of the flange portion 122 was measured in the same cross-section as the main body portion 121, at a position 3 mm away from the free end of the flange portion 122, using the measurement method described in the first embodiment.

[0139] As shown in Table 2, in Examples 3 to 6, the Vickers hardness HV1 of the center of the main body 121 was 105% or more of the Vickers hardness HV2 of the flange portion 122. On the other hand, in Comparative Example 4, the Vickers hardness HV1 of the center of the main body 121 was almost the same as the Vickers hardness HV2 of the flange portion 122. Therefore, according to the manufacturing method of this disclosure, the hardness of the main body 121 can be increased and the strength of the second member 12 can be improved compared to conventional press molding. [Explanation of symbols]

[0140] 10, 10A, 10B, 10C: Cooling components 11: First component 111: Surface 12, 12A, 12Ba, 12Bb, 12C: Second member 121: Main body 122: Flange section 13: Refrigerant flow path 20: Mold 21: First mold 22: Second mold 221: Molding surface 222: Flange surface 23:Protrusion 24: Bead section 25: Seal part 26:Fluid supply path 30,30A,30B,30C:Material 31: First Blank 32, 32A, 32Ba, 32Bb, 32C: Second blank 33: Through hole

Claims

1. A method for manufacturing a cooling member, comprising a plate-shaped first member and a plurality of second members that together form a refrigerant flow path with the first member, wherein each second member includes a flange portion disposed on one surface of the first member and a main body portion having a shape convex to the flange portion, A step of preparing a material that includes a first blank and a plurality of second blanks superimposed on the first blank, wherein through holes are formed in the first blank at positions corresponding to each of the second blanks, or in each of the second blanks, A step of forming the first member from the first blank and forming the second member from the second blank using the first and second molds, Equipped with, The second mold includes a flange surface and a plurality of molding surfaces corresponding to the second blank, each having a concave shape relative to the flange surface. In the molding process, the portion of the first blank and the second blank that will become the flange is held between the first mold and the flange surface, and fluid is supplied between the first blank and the second blank, and the fluid causes each of the second blanks to expand in the hollow space formed between the first mold and the molding surface, thereby molding the main body. A manufacturing method wherein the total area of ​​the region on the surface of the first member in which the refrigerant flow path is provided is 50% or more and less than 90% of the area of ​​the smallest rectangle that circumscribes the second member within the range of the surface.

2. A manufacturing method according to claim 1, The molding process described above is: The process involves inserting the projections provided on the first mold or the flange surface into each of the through holes, and then clamping the portion of the first blank and the second blank that will become the flange portion between the first mold and the flange surface, thereby creating a gap between the first blank and the second blank by the projections, A step of supplying the fluid from the projection into the gap, and using the fluid to expand each of the second blanks within the hollow space to form the main body, A manufacturing method that includes this.

3. A manufacturing method according to claim 1, A method for manufacturing the second member having a Vickers hardness of 120 HV or more.

4. The manufacturing method according to claim 1, further, A manufacturing method comprising a step of heating the material before the molding step.

5. A manufacturing method according to claim 4, A method for manufacturing the second member having a Vickers hardness of 300 HV or more.

6. A mold for manufacturing a cooling member from a material including a first blank and a plurality of second blanks superimposed on the first blank, First mold and A second mold includes a flange surface configured to clamp the material together with the first mold, and a plurality of molding surfaces having a concave shape relative to the flange surface, each configured to form a hollow space with the first mold, In at least one of the first mold and the second mold, a convex bead portion is provided so as to surround each of the hollow spaces, Equipped with, A mold wherein at least one of the first mold and the second mold is provided with a fluid supply passage for supplying fluid to the hollow space.

7. The mold according to claim 6, further, A mold comprising a convex sealing portion provided on at least one of the first mold and the second mold, and arranged to surround the bead portion.

8. A cooling component, A plate-shaped first member, Each of the following second members includes a flange portion disposed on one surface of the first member and a main body portion having a shape convex to the flange portion, and together with the first member, forms a refrigerant flow path. Equipped with, The total area of ​​the region on the surface of the first member in which the refrigerant flow path is provided is 50% or more and less than 90% of the area of ​​the smallest rectangle that circumscribes the second member within the range of the surface. At each side edge in the width direction of the first member, at least one of the second members protrudes outward from the first member. A cooling member wherein, in each of the second members, the rate of reduction in plate thickness at the center of the main body portion, based on the plate thickness of the flange portion, is 5.0% or more.

9. A cooling member according to claim 8, The second member is a cooling member having a Vickers hardness of 120 HV or more.

10. A cooling member according to claim 8, A cooling member wherein, in each of the second members, the Vickers hardness measured at the center of the main body is 105% or more of the Vickers hardness measured at the flange.

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