Cooling bottom and method for manufacturing cooling bottom

Abstract

The invention provides a cooling bottom member and a method for manufacturing the cooling bottom member. A cooling bottom member (100) for cooling a battery cell is provided with: a metal bottom member (101); a flat-plate-shaped metal bottom plate (102) which is disposed so as to face the metal bottom member (101), and which has a surface on the opposite side from the metal bottom member (101) that is in contact with the battery cells; a partition member (105) that is sandwiched between the lower metal bottom member (101) and the flat metal bottom plate (102) without being joined to the lower metal bottom member (101) and the flat metal bottom plate (102); and a joining part (130) formed by directly and continuously joining the outer peripheral edge of the metal underlying member (101) and the outer peripheral edge of the flat-plate-shaped metal bottom plate (102), the region surrounded by the metal underlying member (101), the flat-plate-shaped metal bottom plate (102), and the partition member (105) being a coolant flow path (104) through which a coolant flows.

Description

Technical Field

[0001] The invention relates to a cooling base element and a method for producing the cooling base element. Background Art

[0002] In recent years, fuel consumption restrictions have become stricter worldwide, and electrification is being promoted in the automotive industry. In electric vehicles (EV) and hybrid electric vehicles (HEV), the demand for large-capacity batteries that can be quickly charged is increasing in order to extend the cruising range. Rapid charging batteries (batteries) generate self-heating depending on the conditions of use, and the operating temperature range is determined. When the cells that constitute the battery become hot, the capacity decreases significantly due to changes in internal chemical substances, etc., so the upper limit of the operating temperature is specified. Therefore, in order to prevent the temperature of the battery from exceeding the upper limit temperature, there are many cases where a battery cooling system is provided, and a cooling method based on air cooling is adopted in most current EV and HEV vehicles. On the other hand, it is necessary to efficiently suppress the rise in battery temperature, and as the capacity increases, the use of a water cooling structure in the cooling system is being studied. In addition, in order to extend the cruising range of the car, it is required to increase the number of battery cells and reduce the weight of the cooling system.

[0003] As a water cooling structure of a cooling system, for example, Patent Document 1 discloses a panel formed by joining two plates having a flow path inside facing each other. The two plates have the same shape divided by a plane passing through the center of the flow path. A refrigerant is circulated in the flow path formed inside the panel to cool the cooling object. The flow path meanders inside the panel.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 6064730 Summary of the invention

[0007] Problems to be solved by the invention

[0008] In the case of the structure of Patent Document 1, the production of the flow path inside the panel is complicated and incurs manufacturing costs. That is, the flow path winding inside the panel is formed by, for example, grooving the inner surface of the plate. In addition, since the two plates are of the same shape, it is necessary to perform groove processing on the two plates separately. The thickness of the plate required for the groove processing increases the weight of the panel. In addition, the range where the flow path is not formed is completely joined by brazing, but if the brazing is insufficient, the refrigerant (water) may leak. In the event of a refrigerant leak, water accumulates in the battery pack that accommodates the battery cells and the cooling system, and the battery cells may become flooded in the battery pack. Furthermore, due to the heat from the battery cells, the cooling system is deformed, and the cooling performance may become unstable.

[0009] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a cooling bottom member and a method for manufacturing the cooling bottom member, which can suppress leakage of refrigerant, are lightweight, have stable cooling performance, and are excellent in cooling efficiency.

[0010] Means for solving problems

[0011] In order to solve the above problems, the inventors have conducted in-depth research on a cooling bottom component that suppresses refrigerant leakage, is lightweight, and has excellent cooling efficiency. As a result, the inventors have found that by inserting a partition component (insert) between metal sheets without being joined to the metal sheets, and flowing the refrigerant in the space formed between the metal sheets and the partition component, without performing processing such as groove processing and stamping, a cooling bottom component that suppresses refrigerant leakage, is lightweight, suppresses thermal strain and surface strain, and has excellent cooling efficiency, and a method for manufacturing the cooling bottom component can be obtained.

[0012] The present invention has been accomplished based on the above findings. The gist of the present invention is to adopt the following means.

[0013] (1) A cooling bottom member according to one embodiment of the present invention is a cooling bottom member for cooling a battery cell, and includes:

[0014] Metal bottom parts;

[0015] A flat metal bottom plate is disposed opposite to the metal bottom lower member, and a surface opposite to the metal bottom lower member is in contact with the battery cell;

[0016] A partition member that is not joined to the metal bottom member and the flat metal bottom plate but is clamped thereto; and

[0017] The joint portion is formed by directly and continuously joining the outer peripheral edge of the metal bottom lower member and the outer peripheral edge of the flat metal bottom plate.

[0018] The area surrounded by the metal bottom member, the flat metal bottom plate, and the partition member is a coolant flow path through which the coolant flows.

[0019] According to the cooling bottom member of the above-mentioned structure, since the partition member is sandwiched between the metal bottom member and the flat metal bottom plate and the outer peripheral edge is directly continuously joined, it is unnecessary to process grooves and presses, and it is possible to suppress the leakage of the refrigerant and achieve weight reduction. Furthermore, since the metal bottom plate whose outer surface is in contact with the battery cell is in a flat plate shape, the battery cell can be closely contacted with the cooling bottom member, and the battery cell can be densely arranged on the upper surface of the cooling bottom member without gaps, so that the battery cell can be efficiently cooled.

[0020] (2) In the above (1), the following structure may also be adopted:

[0021] The partition member is a sheet-like solid object.

[0022] (3) In the above (2) or (2), the following structure may be adopted:

[0023] The above-mentioned partition member is a solid resin.

[0024] (4) In the above (3), the following structure may also be adopted:

[0025] The partition member is a viscoelastic resin having a Young's modulus of 0.01 GPa to 0.1 GPa.

[0026] (5) In the above (2), the following structure may also be adopted:

[0027] The sheet-like solid object is made of the same metal as the metal bottom member and the flat metal bottom plate.

[0028] (6) In the above (1), the following structure may also be adopted:

[0029] The metal bottom member and the flat metal bottom plate are made of steel.

[0030] (7) A method for manufacturing a cooling bottom member according to one embodiment of the present invention comprises:

[0031] A step of forming a flow path by arranging a plurality of liquid resins in parallel on a surface of one of the metal bottom member and the flat metal bottom plate in a plan view;

[0032] The step of overlapping the other of the metal bottom member and the flat metal bottom plate on the liquid resin and directly and continuously joining the outer peripheral edge of the metal bottom member to the outer peripheral edge of the flat metal bottom plate; and

[0033] The process of providing a supply pipe for supplying a cooling liquid and a discharge pipe for discharging the cooling liquid to the flow path surrounded by the metal bottom member and the flat metal bottom plate,

[0034] The metal bottom member and the flat metal bottom plate are not bonded to the liquid resin.

[0035] According to the manufacturing method of the cooling bottom member of the above structure, processing such as groove processing and stamping processing is not required, and leakage of refrigerant can be suppressed, and weight reduction can be achieved. Furthermore, since the metal bottom plate whose outer surface is in contact with the battery cell is in a flat plate shape, the battery cell can be closely contacted with the cooling bottom member, and the battery cell can be densely arranged on the upper surface of the cooling bottom member without gaps, so the battery cell can be efficiently cooled.

[0036] (8) A method for manufacturing a cooling bottom member according to one embodiment of the present invention comprises:

[0037] A step of sandwiching a sheet-like solid object including a path portion between the metal bottom member and the flat metal bottom plate, wherein the path portion is a recess or a through hole;

[0038] The step of directly and continuously joining the outer peripheral edge of the metal bottom member to the outer peripheral edge of the flat metal bottom plate; and

[0039] The process of providing a supply pipe for supplying a coolant and a discharge pipe for discharging the coolant to the path portion surrounded by the metal bottom member and the flat metal bottom plate,

[0040] The metal bottom member and the flat metal bottom plate are not joined to the sheet-like solid object.

[0041] According to the manufacturing method of the cooling bottom member of the above structure, processing such as groove processing and stamping processing is not required, and leakage of refrigerant can be suppressed, and weight reduction can be achieved. Furthermore, since the metal bottom plate whose outer surface is in contact with the battery cell is in a flat plate shape, the battery cell can be closely contacted with the cooling bottom member, and the battery cell can be densely arranged on the upper surface of the cooling bottom member without gaps, so the battery cell can be efficiently cooled.

[0042] (9) A method for manufacturing a cooling bottom member according to one embodiment of the present invention comprises:

[0043] A step of coating a surface of one of the metal bottom member and the flat metal bottom plate with a resin;

[0044] a step of peeling off a portion of the coated resin to form a flow path;

[0045] The step of overlapping the other of the metal bottom member and the flat metal bottom plate on the resin and directly and continuously bonding the outer peripheral edge of the metal bottom member to the outer peripheral edge of the flat metal bottom plate; and

[0046] The process of providing a supply pipe for supplying a cooling liquid and a discharge pipe for discharging the cooling liquid to the flow path surrounded by the metal bottom member and the flat metal bottom plate,

[0047] The metal bottom member and the flat metal bottom plate are not bonded to the resin.

[0048] According to the manufacturing method of the cooling bottom member of the above structure, processing such as groove processing and stamping processing is not required, and leakage of refrigerant can be suppressed, and weight reduction can be achieved. Furthermore, since the metal bottom plate whose outer surface is in contact with the battery cell is in a flat plate shape, the battery cell can be closely contacted with the cooling bottom member, and the battery cell can be densely arranged on the upper surface of the cooling bottom member without gaps, so the battery cell can be efficiently cooled.

[0049] Effects of the Invention

[0050] According to the present invention, it is possible to provide a cooling bottom member that can suppress leakage of a refrigerant, is lightweight, has stable cooling performance, and is excellent in cooling efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 This is an exploded perspective view showing an example of the schematic configuration of a battery pack to which the cooling bottom member according to the first embodiment of the present invention is applied.

[0052] Figure 2A It is an exploded perspective view for explaining the schematic structure of the cooling bottom member of the above embodiment.

[0053] Figure 2B (a) is a plan view of the cooling bottom member of the above embodiment, (b) is a cutaway end view along arrow AA' of (a), and (c) is a cross-sectional view along arrow aa' of (b).

[0054] Figure 3A It is an exploded perspective view for explaining a schematic structure of a cooling bottom member according to a second embodiment of the present invention.

[0055] Figure 3B (a) is a plan view of the cooling bottom member of the above embodiment, (b) is a cutaway end view along arrow BB' of (a), and (c) is a cross-sectional view along arrow bb' of (b).

[0056] Figure 4AIt is an exploded perspective view for explaining a schematic structure of a cooling bottom member according to a third embodiment of the present invention.

[0057] Figure 4B (a) is a plan view of the cooling bottom member of the above embodiment, (b) is a cutaway end view along arrow CC' of (a), and (c) is a cross-sectional view along arrow CC' of (b).

[0058] Figure 5A It is a diagram for explaining an example of a method for joining a metal bottom member and a flat metal bottom plate of a cooling bottom member according to an embodiment of the present invention, and is a cross-sectional view of the cooling bottom member.

[0059] Figure 5B It is a diagram for explaining an example of a method for joining a metal bottom member and a flat metal bottom plate of a cooling bottom member according to an embodiment of the present invention, and is a cross-sectional view of the cooling bottom member. DETAILED DESCRIPTION

[0060] The cooling bottom member according to each embodiment of the present invention will be described with reference to the drawings. In the following description, the same reference numerals may be given to the common components in each embodiment, and their repeated description may be omitted.

[0061] In the following description, the longitudinal direction of the cooling bottom member in a plan view is referred to as the X direction, the width direction of the cooling bottom member is referred to as the Y direction, and the thickness direction of the cooling bottom member is referred to as the Z direction.

[0062] Figure 1 It is an exploded perspective view showing an example of the schematic configuration of the battery pack 1 to which the cooling bottom member 100 according to the present embodiment is applied.

[0063] like Figure 1 As shown, the battery pack 1 mainly includes an upper cover 2, battery cells 3, a cooling bottom member 100, and a lower cover 4. The upper cover 2 covers the battery cells 3 from the upper side. The battery cells 3 are closely arranged on the upper surface of the cooling bottom member 100. The lower cover 4 accommodates the cooling bottom member 100 and the battery cells 3 from the lower side.

[0064] exist Figure 1 , the length direction (X direction), width direction (Y direction) and thickness direction (Z direction) of the cooling bottom member 100 are respectively the same as the length direction, width direction and thickness direction of the battery pack 1. Figure 1 In the figure, the positive side in the Z direction is the upper side, and the negative side in the Z direction is the lower side.

[0065] Figure 1The figure shows a case where two battery cells 3 are arranged in the X direction, but the number of battery cells 3 in the X direction is not limited to two. For example, three or more battery cells 3 may be arranged in the X direction, or two or more battery cells 3 may be arranged in the Y direction. There may also be one battery cell 3.

[0066] [First embodiment]

[0067] Reference Figure 2A as well as Figure 2B The cooling bottom member 100A according to the first embodiment will be described.

[0068] Figure 2A It is an exploded perspective view for explaining the schematic structure of the cooling bottom member 100A according to the above embodiment. Figure 2B It means along Figure 2A FIG. 1 is a diagram showing a state in which a flat metal bottom plate 102 and a metal bottom member 101 are joined in a cross section when viewed along arrow AA′.

[0069] The battery cell 3 is placed on the top of the cooling bottom member 100A. The cooling bottom member 100A includes a metal bottom member 101, a flat metal bottom plate 102, and a partition member 105. The flat metal bottom plate 102 and the metal bottom member 101 are arranged opposite to each other, and their outer peripheral edges are directly and continuously joined via the partition member 105. Hereinafter, the portion that is directly and continuously joined is referred to as a joint 130. The area surrounded by the metal bottom member 101, the flat metal bottom plate 102, and the partition member 105 becomes a coolant flow path 104 for the coolant to flow. The surface of the flat metal bottom plate 102 that is on the opposite side to the metal bottom member 101 is in contact with the battery cell 3. With this configuration, the cooling bottom member 100A cools the battery cell 3 placed on the flat metal bottom plate 102 using the coolant flowing in the coolant flow path 104.

[0070] The metal bottom lower member 101 is, for example, an aluminum alloy material or a steel material. When an aluminum alloy material is used for the metal bottom lower member 101, although it is lighter than steel, the plate thickness needs to be thickened, so the battery pack cannot be made compact as a whole. In addition, aluminum alloy materials are more expensive than steel materials. From this point of view, the metal bottom lower member 101 is preferably a steel material. The metal bottom lower member 101 is more preferably a high-strength steel material that has excellent road interference resistance and can effectively ensure space by thinning the wall. High-strength steel is a steel material of 590MPa grade or above.

[0071] The thickness of the metal bottom member 101 is preferably 0.5 mm to 3.2 mm, and more preferably 0.8 mm to 1.6 mm from the viewpoint of weight reduction and strength.

[0072] The flat metal bottom plate 102 is particularly required to have cooling performance. The flat metal bottom plate 102 is, for example, an aluminum alloy material or a steel material. When an aluminum alloy material is used for the flat metal bottom plate 102, although it is lighter than a steel material, the plate thickness needs to be increased, so the battery pack cannot be made compact as a whole. In addition, an aluminum alloy material is more expensive than a steel material. From this point of view, the flat metal bottom plate 102 is preferably a steel material. The flat metal bottom plate 102 is more preferably a high-strength steel material that has excellent cooling performance and can effectively secure space by thinning the wall.

[0073] The thickness of the flat metal bottom plate 102 is preferably thin, but is preferably 0.2 mm to 2.6 mm because it may be damaged by contact of components due to vibration, etc. From the viewpoint of cooling performance, lightness, and strength, the thickness of the flat metal bottom plate 102 is preferably 0.4 mm to 1.0 mm.

[0074] The outer surface of the flat metal bottom plate 102 is flat, that is, it is not concave-convex. The outer surface of the flat metal bottom plate 102 in contact with the battery cell 3 is flat, so the battery cell 3 can be in close contact with the cooling bottom component 100A in a manner of full-surface contact. In addition, the outer surface of the flat metal bottom plate 102 is flat, so there is no restriction on the arrangement of the battery cell 3. That is, the battery cells 3 can be densely arranged on the upper surface of the cooling bottom component 100A without gaps. By making the outer surface of the flat metal bottom plate 102 flat, the battery cell 3 can be efficiently cooled. In addition, there is no need to perform special shape processing and the flat plate can be used, so the processing cost can be reduced.

[0075] From the viewpoint of corrosion resistance, the metal bottom lower member 101 and the flat metal bottom plate 102 are preferably made of the same metal. By making the metal bottom lower member 101 and the flat metal bottom plate 102 of the same metal, it is possible to avoid deterioration caused by contact corrosion of dissimilar metals generated at the connection portion between the outer periphery of the metal bottom lower member 101 and the outer periphery of the flat metal bottom plate 102, or reduction in joining strength caused by fusion joining of dissimilar metals.

[0076] The battery cell 3 is placed on top of the cooling bottom member 100A. The battery cell 3 is, for example, a lithium-ion battery. The battery cell 3 is, for example, in the shape of a rectangular parallelepiped. A plurality of battery cells 3 may be arranged in the X direction. A plurality of battery cells 3 may be arranged in the Y direction. A plurality of battery cells 3 may be stacked in the Z direction. In addition, the battery cell 3 is placed on top of the cooling bottom member 100A, but it is not limited to the case where the battery cell 3 is placed directly on top of the cooling bottom member 100A. For example, it also includes the case where a battery box (not shown) in which the battery cells 3 are bundled and stored is placed on top of the cooling bottom member 100A. In this case, it is preferred that the battery box has a thermal conductivity and thickness that allow heat to be conducted from the battery cell 3 to the cooling bottom member 100A.

[0077] In a state where the metal bottom lower part 101 and the flat metal bottom plate 102 are facing each other and the partition part 105 is sandwiched, the outer peripheral edge of the metal bottom lower part 101 is directly and continuously joined to the outer peripheral edge of the flat metal bottom plate 102. Thus, a cooling liquid flow path 104 is formed inside the cooling bottom part 100A. The partition part 105 is not joined to the metal bottom lower part 101 and the flat metal bottom plate 102, but at least a part of the partition part 105 is sandwiched between the metal bottom lower part 101 and the flat metal bottom plate 102 and fixed. In this fixed area, as long as the partition part 105 is not joined to the metal bottom lower part 101 and the flat metal bottom plate 102, it can be in any state of abutment or close contact. In addition, outside the fixed area, there can also be a gap between the partition part 105 and any one of the metal bottom lower part 101 and the flat metal bottom plate 102. As long as at least the cooling liquid flow path 104 is ensured, the gap amount can be appropriately adjusted. For example, even if the gap exists before the battery cell 3 is placed, the partition member 105 can be fixed by placing the battery cell 3 and bending the flat metal bottom plate 102. In the cooling bottom member 100A, the vicinity of the joint 130 that is directly and continuously joined can become a fixed area. The area ratio of the fixed area, that is, the contact area ratio of the partition member 105 with the metal bottom member 101 and the flat metal bottom plate 102, is preferably 5% or more of the entire partition member 105. In addition, the area ratio of the fixed area can also be 15%, 25%, or 40% or more of the entire partition member 105. Here, the entire partition member 105 represents the total area of ​​the surface on the metal bottom member 101 side and the surface on the flat metal bottom plate 102 side in the partition member 105. In addition, for example, ultrasonic waves are used to continuously scan the entire surface from the flat metal base plate 102 side to measure the contact portion and the non-contact portion, and the contact area ratio between the metal bottom part 101 and the flat metal base plate 102 and the partition part 105 is calculated by the area of ​​the contact portion / the area of ​​the flat metal base plate side of the partition part 105.

[0078] exist Figure 2A 1 shows the state where the metal bottom member 101 and the flat metal bottom plate 102 are not joined. Figure 2B 2 shows a state where the outer periphery of the metal bottom member 101 and the outer periphery of the flat metal bottom plate 102 are directly and continuously joined.

[0079] The partition member 105 is not bonded to the metal bottom member 101 and the flat metal bottom plate 102. The bonding mentioned here includes mechanical bonding such as riveting, screwing, and pressing, metallurgical bonding including welding such as welding, pressing, and brazing, and resin bonding and welding.

[0080] A refrigerant (cooling liquid) flows in the cooling liquid flow path 104 .

[0081] When the height (length in the Z direction) of the cooling liquid flow path 104 is long, more refrigerant can flow, but from the viewpoint of weight reduction and cooling efficiency, the height is preferably 1 mm to 10 mm. The height of the cooling liquid flow path 104 is more preferably 1 mm to 5 mm.

[0082] The cooling liquid flow path 104 is provided with a supply pipe (not shown) for supplying refrigerant, and a drain pipe (not shown) for discharging refrigerant. The supply pipe and the drain pipe are preferably connected to the cooling liquid flow path 104 via the metal bottom part 101. The supply pipe and the drain pipe are arranged according to a cooling design such as respectively connecting to approximately two ends of the cooling liquid flow path 104, or arranging a plurality of drain pipes at both ends of the cooling liquid flow path 104 so that the supply pipe is located approximately in the middle of the cooling liquid flow path 104. The refrigerant supplied from the supply pipe flows through the cooling liquid flow path 104 and is discharged from the drain pipe, and the refrigerant is again supplied from the supply pipe to the cooling liquid flow path 104 after being cooled by a cooling device (not shown).

[0083] The coolant flow path 104 can be formed by arranging a plurality of partition members 105 side by side, and the flow path can be controlled according to the length and path of the flow path so that the flow direction of the refrigerant is consistent. By properly configuring the partition members 105, the battery cells 3 can be efficiently cooled. In the case where there is a gap between the partition member 105 and the metal bottom member 101 or the flat metal bottom plate 102, the coolant leaks from the coolant flow path 104, but since the outer peripheral edge of the cooling bottom member 100A is directly continuously joined to form the joint 130, it will not leak to the outside of the cooling bottom member 100A. In addition, even if the coolant leaks from the coolant flow path 104, the flow of the coolant follows the shape of the coolant flow path 104, so the cooling capacity will not be significantly deteriorated. Alternatively, the gap between the partition member 105 and the metal bottom member 101 or the flat metal bottom plate 102 may be actively utilized to fill the outside of the coolant flow path 104 with the coolant leaking from the coolant flow path 104 and cool the battery cell 3 together with the coolant flowing in the coolant flow path 104 .

[0084] As described above, the structure of the cooling bottom member 100A is such that the partition member 105 is sandwiched between the metal bottom member 101 and the flat metal bottom plate 102, and the outer periphery thereof is directly and continuously joined. Therefore, processing such as groove processing and stamping processing is not required, and refrigerant leakage can be suppressed, and weight reduction can also be achieved. Furthermore, since the metal bottom plate whose outer surface is in contact with the battery cell 3 is in a flat plate shape, the battery cell 3 can be closely contacted with the cooling bottom member 100A, and the battery cell 3 can be densely arranged on the upper surface of the cooling bottom member 100A without gaps, so that the battery cell can be efficiently cooled.

[0085] For example, when the flat metal bottom plate 102 and the partition member 105 are joined, the flat metal bottom plate 102 generates thermal strain due to the linear expansion difference between the flat metal bottom plate 102 and the partition member 105 as the temperature of the flat metal bottom plate 102 changes, and the contact state with the battery cell 3 disposed on the flat metal bottom plate 102 changes, so that the cooling performance may become unstable. Alternatively, when the metal bottom lower member 101 and the partition member 105 are joined, the following problem occurs: when the partition member 105 is hardened, residual strain is generated at the joint interface between the partition member 105 and the metal bottom lower member 101, and the plane strain caused by the accumulation of the residual strain reduces the surface accuracy of the cooling bottom member 100A having a large area, thereby reducing the contact efficiency with the battery cell. In the cooling bottom member 100A, the partition member 105 is not bonded to the metal bottom lower member 101 and the flat metal bottom plate 102, so that the thermal strain caused by thermal changes between the partition member 105 and the metal bottom lower member 101, or between the partition member 105 and the flat metal bottom plate 102 can be avoided. As a result, the close contact between the cooling bottom member 100A and the battery cell 3 does not change, and the cooling performance is stable. Although the above-mentioned problems of thermal strain and plane strain may occur regardless of the material of the partition member 105, they become significant when the partition member 105 is a resin. Therefore, when the partition member 105 is a solid resin, it is particularly effective that both the metal bottom lower member 101 and the flat metal bottom plate 102 are not bonded to the partition member 105.

[0086] Figure 5A as well as Figure 5B 1 is a diagram for explaining an example of a method for joining the metal bottom member 101 and the flat metal bottom plate 102 in the cooling bottom member 100A of the present embodiment, and is a cross-sectional view of the cooling bottom member 100A.

[0087] The outer peripheral edge 101a of the metal bottom lower member 101 and the outer peripheral edge 102a of the flat metal bottom plate 102 are directly and continuously joined (watertightly joined) to form a joint 130. Direct and continuous joining means a joint that is water-tight and does not leak even when water pressure is applied. By directly and continuously joining the outer peripheral edge 101a of the metal bottom lower member 101 and the outer peripheral edge 102a of the flat metal bottom plate 102, it is possible to prevent the refrigerant from leaking from the cooling bottom member 100A.

[0088] Direct continuous joining includes, for example, continuous melting joining, continuous crimping, and continuous sealing joining. The outer peripheral edge 101a of the metal bottom member 101 is continuously joined to the outer peripheral edge 102a of the flat metal bottom plate 102. Continuous melting joining includes, for example, continuous fusion welding using laser welding, resistance seam welding, arc welding, plasma welding, etc. Continuous crimping is solid phase joining using electromagnetic crimping, ultrasonic welding, friction stir welding, etc. Continuous sealing joining is joining using bite processing (mechanical joining) such as folding and curling.

[0089] Although not shown, the supply pipe and the drain pipe are connected to the coolant flow path 104 via the metal bottom member 101. Specifically, the supply pipe and the drain pipe are directly connected to the hole provided in the metal bottom member 101 and connected to the coolant flow path 104 via the hole.

[0090] Figure 5A The figure shows a state where the outer peripheral edge 101a of the metal bottom member 101 and the outer peripheral edge 102a of the flat metal bottom plate 102 are welded. Figure 5B The outer peripheral edge 101a of the metal bottom lower member 101 and the outer peripheral edge 102a of the flat metal bottom plate 102 are shown in a curled state. The outer peripheral edge 101a of the metal bottom lower member 101 and the outer peripheral edge 102a of the flat metal bottom plate 102 may also be riveted.

[0091] The outer peripheral edge 101a of the metal bottom lower member 101 and the outer peripheral edge 102a of the flat metal bottom plate 102 are directly and continuously joined to form the joint 130, thereby preventing the leakage of the refrigerant and preventing the battery cells 3 placed on the cooling bottom member 100A from being flooded. Even if the refrigerant leaks, the continuous melting joining or continuous sealing joining is performed, so the leakage of the refrigerant can be improved only by repairing the outer peripheral edge 101a of the metal bottom lower member 101 and the outer peripheral edge 102a of the flat metal bottom plate 102.

[0092] In this embodiment, if Figure 2A As shown, partition members 105 are arranged so that coolant flow path 104 meanders. By allowing the coolant to flow along partition members 105 arranged in a meandering manner, battery cells 3 can be cooled more efficiently. Coolant flow path 104 may not be a single path but a plurality of paths, or may be mesh-shaped.

[0093] like Figure 2A as well as Figure 2B As shown, in this embodiment, the cooling liquid flow path 104 meanders in such a way that the Y direction becomes the longitudinal direction, but the meandering direction is not limited thereto. For example, the cooling liquid flow path 104 may meander in such a way that the X direction becomes the longitudinal direction. Furthermore, the cooling liquid flow path 104 may not meander.

[0094] The partition member 105 may be a solid resin 106 formed by solidifying a liquid resin. In this case, the cooling liquid flow path 104 is formed by the solid resin 106. The liquid resin is a gel-like resin, such as a sealant.

[0095] An example of a manufacturing method of this embodiment is shown. Here, for example, a plurality of liquid resins are arranged side by side on the surface of one of the metal bottom member 101 and the flat metal bottom plate 102 in a plan view. The liquid resins arranged side by side are solidified to form partition members 105, forming a path of a desired shape. Here, the liquid resin includes a paste resin (also called a gel resin).

[0096] The liquid resin is applied in a stripe shape using, for example, a dedicated gun (application gun) held by a robot, thereby enabling arbitrary flow paths to be arranged.

[0097] The other of the metal bottom lower part 101 and the flat metal bottom plate 102 is overlapped on the solidified resin, that is, on the partition part 105, and the metal bottom lower part 101 and the outer periphery of the flat metal bottom plate 102 are directly and continuously joined, so that the path between the partition parts 105 arranged side by side becomes the coolant flow path 104. In addition, as described above, a supply pipe (not shown) and a discharge pipe (not shown) are provided for the coolant flow path 104. In addition, as for the timing of sandwiching the partition part 105 by the metal bottom lower part 101 and the flat metal bottom plate 102, as long as the metal bottom lower part 101 and the flat metal bottom plate 102 are not joined to the partition part 105, it can be after the resin constituting the partition part 105 is completely solidified, or before the solidification is completed.

[0098] When solid resin is used, since there are no welded portions between the partition member 105, the metal bottom member 101, and the flat metal bottom plate 102, leakage of the refrigerant to the outside of the cooling bottom member 100A from welding defects such as pinholes formed near the welded portions can be avoided.

[0099] The partition member 105 may be a viscoelastic resin 107. The viscoelastic resin 107 is, for example, a rubber-like resin. The partition member 105 may be a viscoelastic resin 107 having a Young's modulus of 0.01 GPa or more and 0.1 GPa or less.

[0100] When the viscoelastic resin 107 is used for the partition member 105, the metal bottom lower member 101 and the flat metal bottom plate 102 have different linear expansion coefficients from the viscoelastic resin 107, but since they are not bonded to each other, the strain generated at the contact interface during expansion and contraction due to temperature changes can be mitigated. Therefore, a stable coolant flow path 104 can be maintained. Furthermore, the out-of-plane deformation of the metal bottom lower member 101 and the flat metal bottom plate 102 is small, and the shape of the metal bottom lower member 101 and the flat metal bottom plate 102 can be easily maintained flat.

[0101] The viscoelastic resin 107 is applied in a stripe shape using, for example, a dedicated gun held by a robot, whereby an arbitrary flow path can be arranged.

[0102] Similar to the case of using solid resin, when the viscoelastic resin 107 is used for the partition component 105, since there are no welding locations between the partition component 105 and the metal bottom member 101 and the flat metal bottom plate 102, it is possible to prevent the refrigerant from leaking to the outside of the cooling bottom component 100A through welding defects such as pinholes formed near the welding portions.

[0103] [Second embodiment]

[0104] Reference Figure 3A as well as Figure 3B A cooling bottom member 100B according to a second embodiment will be described. In the second embodiment, the same components as those of the first embodiment are denoted by the same reference numerals and their descriptions are omitted, and only the differences will be described.

[0105] The present embodiment is different from the first embodiment in that the partition member 105 is a sheet-like solid object 110 .

[0106] When viewed from above, if the distance between the metal bottom lower part 101 and the outer periphery of the flat metal bottom plate 102 in the X direction or the Y direction and the partition part 105 is close, it is difficult to make the distance between the metal bottom lower part 101 and the flat metal bottom plate 102 in the height direction (thickness direction) close due to the partition part 105, and sometimes it is impossible to directly and continuously join the two. In the case where the partition part 105 is a sheet-like solid object, the possibility of such poor welding increases due to the large area of ​​the partition part 105 near the corresponding outer periphery. Therefore, in the present structure, it is preferred that the shortest distance from the end of the partition part 105 to the joint 130 in a plan view is 9.5 times or more of the thickness of the partition part 105, or Figure 5A The metal bottom member 101 is subjected to press working in this manner. Such a structure is also preferred in other embodiments.

[0107] Figure 3AIt is an exploded perspective view for explaining a schematic structure of the cooling bottom member 100B according to the present embodiment. Figure 3B It means along Figure 3A The figure shows the state of the flat metal bottom plate 102 and the metal bottom lower part 101 being joined in the cross section when viewed along the arrow BB'. Figure 3A 1 shows the state where the metal bottom member 101 and the flat metal bottom plate 102 are not joined. Figure 3B 2 shows a state where the outer peripheral edge of the metal bottom member 101 and the outer peripheral line of the flat metal bottom plate 102 are directly and continuously joined.

[0108] The sheet-like solid object 110 is formed, for example, by stamping a flat resin or a flat steel plate. Thus, the sheet-like solid object 110 is provided with a path portion 140 (e.g., a recess or a through hole) which becomes the coolant flow path 104 and a plane portion 141 (e.g., an unprocessed area) around it. In the present embodiment, a partition member 105 serving as the sheet-like solid object 110 is sandwiched between the metal bottom lower member 101 and the flat metal bottom plate 102, and the metal bottom lower member 101 and the outer peripheral edge of the flat metal bottom plate 102 are directly and continuously joined. At this time, the metal bottom lower member 101 and the flat metal bottom plate 102 are not joined to the sheet-like solid object. In addition, as described above, a supply pipe (not shown) and a discharge pipe (not shown) are provided for the path portion (coolant flow path 104).

[0109] The partition member 105 of this embodiment is in the form of a sheet, so it is easy to manufacture in accordance with the desired shape of the coolant flow path 104, and the degree of freedom in layout design is high. Furthermore, the shape of the flow path can be easily confirmed visually.

[0110] In this embodiment, if Figure 3A as well as Figure 3B As shown, the sheet-like solid object 110 is arranged along the Y direction, but the arrangement direction of the sheet-like solid object 110 is not limited thereto. For example, the sheet-like solid object 110 may be arranged along the X direction. In addition, the sheet-like solid object 110 may be arranged in a manner such that the coolant flow path 104 meanders as in the first embodiment.

[0111] By causing the coolant to flow along the sheet-like solid object 110 arranged in this manner, the battery cells 3 can be cooled more efficiently.

[0112] The sheet-like solid object 110 may also be a solid resin 111. The solid resin 111 is, for example, a hard resin, specifically, an epoxy resin.

[0113] When the solid resin 111 is used, since the compressive strength is high, it is possible to prevent the flat metal bottom plate 102 from being deformed by the weight of the loaded battery cells 3. In particular, when the sheet-like solid object 110 is used as the partition member 105, since the area of ​​the partition member 105 facing the flat metal bottom plate 102 is large, the above-mentioned deformation prevention effect is high.

[0114] When the solid resin 111 is used, since there are no welded portions between the partition member 105 and the metal bottom member 101 and the flat metal bottom plate 102, leakage of the refrigerant to the outside of the cooling bottom member 100B from welding defects such as pinholes formed near the welded portions can be avoided.

[0115] The sheet-like solid object 110 may also be a viscoelastic resin 112. The viscoelastic resin 112 is, for example, a vinyl chloride resin.

[0116] When the viscoelastic resin 112 is used, the metal bottom lower member 101 and the flat metal bottom plate 102 have different linear expansion coefficients from the viscoelastic resin 112, so that the strain generated at the contact interface during expansion and contraction with respect to temperature changes can be alleviated. Therefore, a stable coolant flow path 104 can be maintained. Furthermore, the out-of-plane deformation of the metal bottom lower member 101 and the flat metal bottom plate 102 is small, and the shape of the metal bottom lower member 101 and the flat metal bottom plate 102 can be easily maintained flat.

[0117] Similar to the case of using the solid resin 111, when using the viscoelastic resin 112, since there are no welding locations between the partition member 105 and the metal bottom member 101 and the flat metal bottom plate 102, it is possible to prevent the refrigerant from leaking to the outside of the cooling bottom member 100B through welding defects such as pinholes formed near the welding portions.

[0118] The sheet solid object 110 may also be the same metal 113 as the metal bottom member 101 and the flat metal bottom plate 102. Thus, it is possible to avoid deterioration caused by contact corrosion of dissimilar metals at the connection between the sheet solid object 110, the metal bottom member 101 and the flat metal bottom plate 102, or reduction in joining strength caused by fusion joining of dissimilar metals.

[0119] [Third Embodiment]

[0120] Reference Figure 4A as well as Figure 4B A cooling bottom member 100C according to a third embodiment will be described. In the third embodiment, the same components as those of the first embodiment are denoted by the same reference numerals and their descriptions are omitted, and only the differences will be described.

[0121] The present embodiment is different from the first embodiment in that the partition member is a covering resin formed by covering the partition member with a resin.

[0122] Figure 4A It is an exploded perspective view for explaining the schematic structure of the cooling bottom member according to the present embodiment. Figure 4B It means along Figure 4A FIG. 1 is a diagram showing a state in which the flat metal bottom plate 102 and the metal bottom member 101 are joined in a cross section when viewed along the arrow CC'. Figure 4A 1 shows the state where the metal bottom member 101 and the flat metal bottom plate 102 are not joined. Figure 4B 2 shows a state where the outer peripheral edge of the metal bottom member 101 and the outer peripheral edge of the flat metal bottom plate 102 are directly and continuously joined.

[0123] In the present embodiment, the cooling liquid flow path 104 is formed by peeling off a part of the resin (covering resin 120 ) covering the surface of one of the metal bottom member 101 and the flat metal bottom plate 102 . Figure 4A (a) shows a state where the upper surface of the metal bottom member 101 is covered with resin, and is a state before the covering resin 120 is peeled off. Figure 4A (b) shows a state where a part of the covering resin 120 is peeled off.

[0124] For example, Figure 4A As shown in (a), a resin is covered on one surface of the metal bottom lower part 101 (the upper surface of the metal bottom lower part 101). Secondly, a part of the covered resin is peeled off to form a flow path, the flat metal bottom plate 102 is overlapped on the resin, and the outer peripheral edge of the metal bottom lower part 101 is directly and continuously joined to the outer peripheral edge of the flat metal bottom plate 102. As a result, the resin that is not peeled off and remains becomes the partition member 105, and the path after peeling becomes the coolant flow path 104. In addition, as described above, a supply pipe (not shown) and a discharge pipe (not shown) are provided for the coolant flow path 104. Here, the resin that is not peeled off from the metal bottom lower part 101 and remains, that is, the partition member 105, is separated from the metal bottom lower part as time passes. The separation period can be before the flat metal bottom plate 102 is directly and continuously joined, or it can be after the joining. The joint 130 where the metal bottom lower part 101 and the flat metal bottom plate 102 are directly and continuously joined is not covered with resin, or even if it is covered with resin, it is peeled off before the direct and continuous joining. In addition, similarly to the above, a supply pipe (not shown) and a discharge pipe (not shown) are provided in the cooling liquid flow path 104 .

[0125] For example, the resin is preliminarily coated on the metal bottom part 101. The method of coating the metal bottom part 101 with the resin is, for example, coating by hot pressing or bonding. Alternatively, coating is performed by slit coating or dip coating. In the present embodiment, as described above, the resin coated on the metal bottom part 101 is bonded to the metal bottom part 101 with a bonding force to the extent that the metal bottom part 101 can be separated. In order to achieve such a bonding force, for example, during hot pressing, it is preferred that the constructor selects conditions in which the applied pressure and the heating temperature are appropriately adjusted. Furthermore, for example, as an adhesive used for bonding, it is preferred that the constructor selects a material in which the bonding strength is appropriately adjusted.

[0126] The thickness of the covering resin is 1 mm to 7 mm. Although it depends on the shape of the water channel and the required amount of water, from the viewpoint of moldability, the thickness of the covering resin is preferably 1 mm to 5 mm. The thickness of the covering resin is more preferably 3 mm.

[0127] The covering resin is peeled off by, for example, a cutter, punching, or laser processing.

[0128] The covering resin 120 can be easily peeled off in accordance with the desired shape of the cooling liquid flow path 104, and the degree of freedom in layout design is high. Furthermore, the shape of the flow path can be easily confirmed visually.

[0129] The covering resin 120 can be provided by covering a metal coil or a metal sheet, and therefore, the possibility of the covering resin 120 falling off during the manufacturing process of the cooling liquid flow path 104 is low.

[0130] In this embodiment, if Figure 4A as well as Figure 4B As shown, the covering resin 120 is arranged along the Y direction, but the arrangement direction of the covering resin 120 is not limited thereto. For example, the covering resin 120 may be arranged along the X direction. In addition, the covering resin 120 may be peeled off so that the cooling liquid flow path 104 meanders as in the first embodiment.

[0131] By allowing the coolant to flow along the cover resin 120 disposed in this manner, the liquid battery cells 3 can be cooled more efficiently.

[0132] The covering resin may be a solid resin 121. The solid resin 121 is, for example, a hard resin, and specifically, a vinyl chloride resin.

[0133] When the solid resin 121 is used, since the compression strength is high, it is possible to prevent the flat metal base plate 102 from being deformed by the weight of the loaded battery cells 3. In particular, when the resin covers a large area, the area of ​​the partition member 105 facing the flat metal base plate 102 becomes large, so the deformation prevention effect is high.

[0134] When solid resin 121 is used, since there are no welded portions between partition member 105, metal bottom member 101, and flat metal bottom plate 102, leakage of refrigerant to the outside of cooling bottom member 100A from welding defects such as pinholes formed near welded portions can be avoided.

[0135] The covering resin may be a viscoelastic resin 122. The viscoelastic resin 122 is, for example, polyethylene resin.

[0136] When the viscoelastic resin 122 is used, the metal bottom lower member 101 and the flat metal bottom plate 102 have different linear expansion coefficients from the viscoelastic resin 112, so that the strain generated at the contact interface during expansion and contraction with respect to temperature changes can be alleviated. Therefore, a stable coolant flow path 104 can be maintained. Furthermore, the out-of-plane deformation of the metal bottom lower member 101 and the flat metal bottom plate 102 is small, and the shape of the metal bottom lower member 101 and the flat metal bottom plate 102 can be easily maintained flat.

[0137] Similar to the case of using the solid resin 121, when using the viscoelastic resin 122, since there are no welding locations between the partition member 105 and the metal bottom member 101 and the flat metal bottom plate 102, it is possible to prevent the refrigerant from leaking to the outside of the cooling bottom member 100C through welding defects such as pinholes formed near the welding portions.

[0138] The cooling bottom members 100A, 100B, and 100C described in the above-mentioned embodiments are applied to, for example, electric vehicles and hybrid vehicles.

[0139] The embodiments of the present invention are described above, but the embodiments are presented as examples, and the scope of the present invention is not limited to the embodiments. The embodiments can be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the disclosed subject matter. The embodiments and their variations are included in the disclosed scope and subject matter, and are included in the disclosure and equivalent scope recorded in the scope of the patent claims.

[0140] For example, Figure 1 As shown, the cooling bottom member in each of the above-described embodiments is disposed between the lower cover 4 and the battery cell 3 , but may be disposed between the battery cells 3 when a plurality of battery cells 3 are stacked in the Z direction.

[0141] Industrial Applicability

[0142] According to the present invention, a cooling bottom member and a method for manufacturing the cooling bottom member can be provided, which can suppress leakage of refrigerant, are lightweight, have stable cooling performance, and are excellent in cooling efficiency. Therefore, the industrial applicability is high.

[0143] Explanation of symbols

[0144] 1: battery pack; 2: upper side cover; 3: battery cell; 4: lower side cover; 100, 100A, 100B, 100C: cooling bottom part; 101: metal bottom bottom part; 101a, 102a: outer periphery; 102: flat metal bottom plate; 104: cooling liquid flow path; 105: partition part (insert part); 106, 111, 121: solid resin; 107, 112, 122: viscoelastic resin; 110: sheet solid; 120: covering resin; 130: joint part.

Claims

1. A cooling bottom member for cooling a battery cell, comprising: Metal bottom parts; A flat metal bottom plate is disposed opposite to the metal bottom lower member, and a surface opposite to the metal bottom lower member is in contact with the battery cell; A partition member that is not joined to the metal bottom member and the flat metal bottom plate but is clamped thereto; and The joint portion is formed by directly and continuously joining the outer peripheral edge of the metal bottom lower member and the outer peripheral edge of the flat metal bottom plate. The area surrounded by the metal bottom member, the flat metal bottom plate, and the partition member is a coolant flow path through which the coolant flows.

2. The cooling bottom element according to claim 1, wherein: The partition member is a sheet-like solid object.

3. The cooling bottom element according to claim 1 or 2, wherein: The above-mentioned partition member is a solid resin.

4. The cooling bottom element according to claim 3, wherein: The partition member is a viscoelastic resin having a Young's modulus of 0.01 GPa to 0.1 GPa.

5. The cooling bottom member according to claim 2, wherein: The sheet-like solid object is made of the same metal as the metal bottom member and the flat metal bottom plate.

6. The cooling bottom member according to claim 1, wherein: The metal bottom member and the flat metal bottom plate are made of steel.

7. A method for manufacturing a cooling bottom member, comprising: A step of forming a flow path by arranging a plurality of liquid resins in parallel on a surface of one of the metal bottom member and the flat metal bottom plate in a plan view; The step of overlapping the other of the metal bottom member and the flat metal bottom plate on the liquid resin and directly and continuously joining the outer peripheral edge of the metal bottom member to the outer peripheral edge of the flat metal bottom plate; and The process of providing a supply pipe for supplying a cooling liquid and a discharge pipe for discharging the cooling liquid to the flow path surrounded by the metal bottom member and the flat metal bottom plate, The metal bottom member and the flat metal bottom plate are not bonded to the liquid resin.

8. The method for manufacturing a cooling bottom member according to claim 7, comprising: A step of sandwiching a sheet-like solid object including a path portion between the metal bottom member and the flat metal bottom plate, wherein the path portion is a recess or a through hole; The step of directly and continuously joining the outer peripheral edge of the metal bottom member to the outer peripheral edge of the flat metal bottom plate; and The process of providing a supply pipe for supplying a coolant and a discharge pipe for discharging the coolant to the path portion surrounded by the metal bottom member and the flat metal bottom plate, The metal bottom member and the flat metal bottom plate are not joined to the sheet-like solid object.

9. A method for manufacturing a cooling bottom member, comprising: A step of coating a surface of one of the metal bottom member and the flat metal bottom plate with a resin; a step of peeling off a portion of the resin covered to form a flow path; The step of overlapping the other of the metal bottom member and the flat metal bottom plate on the resin and directly and continuously bonding the outer peripheral edge of the metal bottom member to the outer peripheral edge of the flat metal bottom plate; and The process of providing a supply pipe for supplying a cooling liquid and a discharge pipe for discharging the cooling liquid to the flow path surrounded by the metal bottom member and the flat metal bottom plate, The metal bottom member and the flat metal bottom plate are not bonded to the resin.

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