Cooler and method for manufacturing battery pack

Abstract

The invention provides a cooler and a method for manufacturing a battery pack. The present invention relates to a battery cooling device in which a cooler is alternately stacked with batteries and cools the batteries, the cooler having a cooling unit disposed between adjacent batteries in the stacking direction, the cooling unit having: a flow path through which a coolant flows; a first cooling surface which is a cooling surface in contact with one of the batteries; a second cooling surface which is a cooling surface in contact with the other of the batteries; a first protrusion protruding in the stacking direction from the rear surface of the first cooling surface toward the rear surface of the second cooling surface; and a second protrusion protruding in the stacking direction from the rear surface of the second cooling surface toward the first cooling surface, the flow path is formed by an internal space in which the rear surfaces of the cooling surfaces face each other, and the first protrusion and the second protrusion face each other when the first cooling surface and the second cooling surface are in contact with the battery surface.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a cooler and a battery pack. Background Technology

[0002] Japanese Patent Application Publication No. 2024-509489 discloses a battery pack in which a cooling device for cooling battery cells is disposed inside a housing accommodating multiple battery cells. In the structure described in Japanese Patent Application Publication No. 2024-509489, the cooling device has multiple coolers, and the multiple coolers and multiple battery cells are alternately stacked. Summary of the Invention

[0003] In structures where battery cells and coolers are alternately stacked, as described in Japanese Patent Application Publication No. 2024-509489, the cooler is compressed and deformed during use due to the expansion of the battery cells. In this case, if the cooler is compressed significantly, the flow path of the coolant inside the cooler narrows, and the cooling performance decreases.

[0004] The present invention was made in view of the above circumstances, and its object is to provide a cooler and a method for manufacturing a battery pack that can prevent the coolant flow path from being crushed by the battery expanding during use, thereby ensuring cooling performance.

[0005] As a cooler of the present invention, the cooler is alternately stacked with batteries to cool the batteries. The cooler is characterized by having a cooling section disposed between adjacent batteries in the stacking direction. The cooling section includes: a flow path for coolant to flow through; a first cooling surface that contacts one of the batteries; a second cooling surface that contacts the other of the batteries; a first protrusion that protrudes from the back of the first cooling surface toward the back of the second cooling surface in the stacking direction; and a second protrusion that protrudes from the back of the second cooling surface toward the back of the first cooling surface in the stacking direction. The flow path is formed in the internal space where the backs of the cooling surfaces face each other. When the first and second cooling surfaces are in surface contact with the batteries, the first and second protrusions face each other in the stacking direction inside the cooling section.

[0006] As a method for manufacturing a battery pack according to the present invention, the battery pack includes the cooler of the present invention, characterized in that the manufacturing method includes: an insertion step in which, with a cooling device formed by a plurality of the coolers disposed inside a housing containing a plurality of battery cells, the battery cells are inserted between adjacent coolers, with the cooling surfaces of the coolers facing each other; and a deformation step in which, after the battery cells are inserted between the coolers, the internal pressure of the coolers is increased to deform the coolers so that the cooling surfaces contact the battery cells. Inside the coolers before deformation in the insertion step, the first protrusion and the second protrusion do not face each other in the stacking direction, and inside the coolers after deformation in the deformation step, the first protrusion and the second protrusion face each other in the stacking direction.

[0007] According to the present invention, the flow path of the coolant can be prevented from being crushed by the expanding battery during use, thus ensuring cooling performance. Attached Figure Description

[0008] The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described with reference to the accompanying drawings, wherein like reference numerals denote like elements, and the drawings include:

[0009] Figure 1 This is a schematic diagram illustrating the battery pack in the embodiment;

[0010] Figure 2 This is a diagram used to illustrate the cooling device;

[0011] Figure 3 This is a diagram used to illustrate the cooler;

[0012] Figure 4 This is a diagram used to illustrate the cooling section;

[0013] Figure 5 Part (a) is a diagram illustrating the shape of the state after extrusion molding, part (b) is a diagram illustrating the shape during deformation when pressure is applied to the inside of the cooler, and part (c) is a diagram illustrating the shape after deformation when pressure is applied to the inside of the cooler.

[0014] Figure 6 This diagram illustrates the state in which the battery cells expand during use and the protrusions inside the cooling section support each other.

[0015] Figure 7 Part (a) is a diagram illustrating the insertion process, part (b) is a diagram illustrating the process of the deformation process, and part (c) is a diagram illustrating the state after the deformation process is completed.

[0016] Figure 8A This is a diagram used to illustrate the structure of a corner section with a thin-walled portion;

[0017] Figure 8B These are diagrams used to illustrate other shapes of thin-walled sections; and

[0018] Figure 8C This is a diagram used to illustrate another shape of a thin-walled section. Detailed Implementation

[0019] The following describes in detail the manufacturing method of the cooler and battery pack according to embodiments of the present invention. However, the present invention is not limited to the embodiments described below.

[0020] Figure 1 This diagram schematically illustrates a battery pack in an embodiment. The battery pack 1 includes multiple battery cells 2, a housing 3, and a cooling device 4. The battery pack 1 is mounted on an electric vehicle. The electric vehicle equipped with the battery pack 1 propels itself by supplying the electricity stored in the battery pack 1 to a driving motor.

[0021] Battery cell 2 is a battery formed in a cuboid shape. Battery cell 2 includes a flat surface 2a with the largest area on its surface. Battery cell 2 is arranged inside housing 3 with the flat surface 2a facing the X direction. The X direction is the first direction. Inside housing 3, multiple battery cells 2 are stacked in the X direction.

[0022] The housing 3 houses the battery cells 2 and the cooling device 4. Inside the housing 3, multiple battery cells 2 constitute a battery module. The housing 3 is a battery pack housing that accommodates multiple battery modules.

[0023] The cooling device 4 cools the battery cell 2 using a coolant. The cooling device 4 includes multiple coolers 20 and a pair of tubes 30.

[0024] Coolers 20 and battery cells 2 are alternately stacked to cool the battery cells 2. Coolers 20 are constructed from extruded metal parts. Coolers 20 extend in the Y direction. Coolers 20 have a cooling surface 20a that contacts the battery cells 2. Figure 2 As shown, the cooling device 4 is an integral structure consisting of multiple coolers 20 joined to a pair of pipes 30, with the cooling surfaces 20a of the coolers 20 facing each other. The coolers 20 are configured to be deformable, thereby increasing their thickness in the X direction. Figure 2 The image shows a cooler 20 with a small thickness in the X direction before deformation. Figure 1 The deformed cooler 20 with increased thickness in the X direction is shown. The cooler 20 is manufactured to be thinner than when in use and is brazed onto the tube 30.

[0025] like Figure 1As shown, in the completed state of the battery pack 1, a stack of multiple coolers 20 and multiple battery cells 2 are formed alternately in the X direction inside the housing 3. Coolers 20 are positioned at both ends of the stack in the X direction. The stacking direction is the same as the X direction. Since the battery cells 2 are square and the coolers 20 are flat, one battery cell 2 is held between two coolers 20. The battery cells 2 and coolers 20 are stacked with the largest surface area among multiple surfaces in contact. The cooling surface 20a contacts the flat surface 2a of the battery cell 2. The cooling surface 20a includes a first cooling surface that contacts one of the adjacent battery cells 2 and a second cooling surface that contacts the other of the adjacent battery cells 2.

[0026] The cooler 20 has a cooling section 21 and a connecting section 22.

[0027] Cooling sections 21 are disposed between adjacent battery cells 2 in the stacking direction. Cooling sections 21 are portions including cooling surfaces 20a. Figure 3 As shown, the cooling section 21 is a hollow plate component. A flow path 23 for coolant circulation is provided inside the cooling section 21. The internal space of the cooling section 21 is the coolant flow path 23. The flow path 23 is formed by internal spaces where the back surfaces of the cooling surfaces 20a face each other. The cooling section 21 and the battery cell 2 form a laminate. Figure 1 As shown, with the cooling device 4 housed within the housing 3, the cooling section 21 extends in the Y direction, which is orthogonal to the X direction. The Y direction is the second direction.

[0028] Connection portions 22 are formed on both ends of the cooling portion 21 and are connected to the pipe 30. In the cooling device 4, the coolers 20 are arranged facing each other with their cooling surfaces 20a facing each other, and the connection portions 22 of the coolers 20 are engaged with the pipe 30.

[0029] The tube 30 is a square tube extending along the X direction. The tube 30 is made of an extruded metal component. Multiple coolers 20 are connected to the tube 30. The tube 30 has multiple connection ports 31. Each connection port 31 is an opening in the Y direction. The tube 30 is formed by extrusion molding, and the connection ports 31 are machined to form the tube. A connection portion 22 of the cooler 20 is connected to the connection port 31. With the connection portion 22 fitted into the connection port 31, the cooler 20 is engaged with the tube 30.

[0030] A first end cap 32 and a second end cap 33 are joined to the pipe 30. The first end cap 32 is joined to the pipe 30 such that it covers one open end of the pipe 30 in the X direction. The second end cap 33 is joined to the pipe 30 such that it covers the other open end of the pipe 30 in the X direction. In this pair of pipes 30, a first pipe section 34 is joined to one first end cap 32, and a second pipe section 35 is joined to another first end cap 32. The first pipe section 34 is the inlet-side pipe section. Coolant supplied to the cooling device 4 flows into the interior of the cooling device 4 from the first pipe section 34. The second pipe section 35 is the outlet-side pipe section. Coolant discharged from the cooling device 4 flows out to the exterior of the cooling device 4 from the second pipe section 35.

[0031] In the cooling device 4, the cooling section 21 is deformable in such a way that the cooling surface 20a is displaced in the X direction according to the internal pressure of the cooler 20. The cooling section 21 has a deformable section 21a. The deformable section 21a is a portion that deforms by increasing the thickness of the cooling section 21 in the X direction. Figure 3 As shown, the deformable part 21a is formed into a shape that is inclined relative to the X direction.

[0032] Figure 4 This is a diagram used to illustrate the cooling system. Additionally, Figure 4 The image shows the state of the deformable part 21a before deformation, that is, the state of the cooler 20 after it has just been extruded.

[0033] The cooling section 21 has a parallelogram shape immediately after extrusion molding. The cooling section 21 has protrusions 21b that project from the back side of the cooling surface 20a in the stacking direction. The protrusions 21b are designed to ensure internal space within the cooling section 21 during use. Inside the cooling section 21, a pair of protrusions 21b are provided on opposing inner surfaces in the stacking direction. Each protrusion 21b includes: a first protrusion projecting from the back side of one cooling surface 20a toward the back side of another cooling surface 20a in the stacking direction; and a second protrusion projecting from the back side of the other cooling surface 20a toward the back side of one cooling surface 20a in the stacking direction. In the cooling section 21 immediately after extrusion molding, the pair of protrusions 21b are arranged alternately.

[0034] The deformable portion 21a is inclined relative to the cooling surface 20a in its state before deformation. At both ends of the deformable portion 21a before deformation, one corner 21c between the deformable portion 21a and the cooling surface 20a is formed as an obtuse angle, and the other corner 21d between the deformable portion 21a and the cooling surface 20a is formed as an acute angle.

[0035] In the cooling section 21, the cooling surface 20a extends along the Z direction before and after deformation. That is, during the deformation of the deformation section 21a, the cooling surface 20a maintains its position along the Z direction, so the cooling section 21 deforms in a way that it thickens in the X direction.

[0036] like Figure 5 As shown in part (a), in the state before deformation of the deformable part 21a, the cooling part 21 is thin in the X direction. Figure 5 As shown in part (b), during the deformation process of the deformed section 21a, the thickness of the cooling section 21 in the X direction becomes thicker than before deformation. Figure 5 As shown in part (c), in the deformed state of the deformable portion 21a, the cooling portion 21 is thickest in the X direction. When the two cooling surfaces 20a are in surface contact with the flat surface 2a of the battery cell 2, inside the cooling portion 21, a pair of protrusions 21b face each other in the stacking direction. After deformation by applying internal pressure, the pair of protrusions 21b are aligned in the Z direction. The deformable portion 21a is orthogonal to the cooling surface 20a in the deformed state. The deformed cooling portion 21 has a rectangular shape.

[0037] like Figure 6 As shown, when the battery cell 2 expands and the cooling surface 20a deforms, narrowing the internal space of the cooling section 21, a pair of protrusions 21b abut against each other inside the cooling section 21, with the back surfaces of one cooling surface 20a separated from the back surfaces of the other cooling surface 20a. With the pair of protrusions 21b abutting against each other, the load exerted on the cooling surface 20a by the battery cell 2 is borne by the pair of protrusions 21b, 21b, to prevent the flow path 23 from being crushed and blocked. The cooling section 21 has a shape such that, once expanded and deformed, the pair of protrusions 21b support each other, preventing the cooling section 21 from returning to a thin state. Even if the battery cell 2 expands during use, the support of the pair of protrusions 21b inside the cooling section 21 prevents the flow path 23 from being crushed and blocked.

[0038] The manufacturing method of the battery pack 1 includes a joining process, a setting process, an insertion process, and a deformation process. In this manufacturing method, after the battery cell 2 is assembled into the cooler 20, the cooler 20 is expanded by applying internal pressure to make the cooler 20 fit tightly against the battery cell 2.

[0039] The joining process is the process of joining multiple coolers 20 with a pair of tubes 30. In the joining process, the components of the cooling device 4, which forms an integral structure, are joined in such a manner that the cooling surfaces 20a of the coolers 20 face each other. Through the joining process, a... Figure 2 The cooling device 4 shown.

[0040] The installation process involves installing the cooling device 4 of the integrated structure inside the housing 3. In this process, the cooling device 4 of the integrated structure is installed inside the housing 3 when the battery unit 2 is not installed.

[0041] The insertion process involves inserting the battery cells 2 between the coolers 20. In this process, with the cooling devices 4 installed in the housing 3, the battery cells 2 are inserted between adjacent coolers 20, wherein the cooling devices 4 are configured such that the cooling surfaces 20a of the coolers 20 face each other. Before inserting the battery cells 2, the coolers 20 are in a thin state. The coolers 20 are extruded into this thin shape.

[0042] like Figure 7 As shown in part (a), in the insertion process, with the cooler 20 in an undeformed state, the battery cell 2 is positioned in a space where the cooling surfaces 20a face each other, at a position where the flat surface 2a does not contact the cooling surface 20a. The insertion process includes the step of positioning the battery cell 2 in a position where the battery cell 2 does not contact the cooler 20 while the cooler 20 is undeformed. When inserting the battery cell 2, there is a gap between the cooler 20 and the battery cell 2. Inside the cooler 20 before deformation in the insertion process, as shown... Figure 7 Part (a) and Figure 5 As shown in part (a), a pair of protrusions 21b do not face each other in the stacking direction.

[0043] The deformation process is a process that increases the internal pressure of the cooler 20, causing the cooling section 21 to expand. In the deformation process, after the battery cell 2 is inserted between the coolers 20, the internal pressure of the cooler 20 is increased, causing the cooler 20 to deform so that the cooling surface 20a contacts the battery cell 2.

[0044] When pressure is applied to the interior of the cooler 20 through the deformation process, such as Figure 7 As shown in part (b), the cooler 20 begins to expand. During the deformation process, when pressure is applied to the interior of the cooler 20, as... Figure 7 As shown in part (c), the cooler 20 is in an expanded state. Inside the deformed cooler 20 during the deformation process, as... Figure 7 Part (c) and Figure 5 As shown in part (c), a pair of protrusions 21b are facing each other and separated in the stacking direction.

[0045] In addition, the deformation process includes the process of bringing the cooling surface 20a into contact with the battery cell 2 to form a laminate of the cooler 20 and the battery cell 2, and using the cooler 20 to compress the battery cell 2 along the lamination direction of the laminate.

[0046] For example, in the deformation process, after the cooling device 4 is placed inside the housing 3, the second pipe 35 side is closed using a valve or the like, and coolant is supplied from the first pipe 34 side using a pump or the like, applying pressure to the inside of the cooler 20. As the pressure inside the cooler 20 increases, the deformation portion 21a is deformed by widening the flow path 23 in the X direction. In the deformation process, the cooling surface 20a is brought into close contact with the battery cell 2 by deforming the cooling portion 21 to increase its thickness in the X direction. In the deformation process, the cooling surface 20a abuts against the flat surface 2a of the battery cell 2 by deforming the cooler 20. After the battery cell 2 is inserted into the opposing space between the cooling surfaces 20a, coolant is supplied from the pump to the first pipe 34, and the pressure inside the cooling device 20 increases. When the internal pressure of the cooling device 20 increases and the thickness of the cooling portion 21 in the X direction increases during deformation, the cooling surface 20a can come into close contact with the flat surface 2a. In the deformation process, the cooling surface 20a is brought into contact with the battery cell 2 to form a laminated body consisting of the cooler 20 and the battery cell 2, and the cooler 20 is used to compress the battery cell 2 along the stacking direction of the laminated body.

[0047] As explained above, according to the embodiment, even if the battery cell 2 expands during use, the flow path 23 can be prevented from collapsing due to the pair of protrusions 21b provided inside the cooling section 21. This ensures the cross-sectional area of ​​the flow path 23 and guarantees cooling performance.

[0048] Furthermore, there is no particular limitation on the number of battery cells 2. The number of battery cells 2 stacked in the X direction is not limited. It can also be a configuration in which multiple battery cells 2 are arranged in the Y direction.

[0049] Furthermore, in the cooling section 21, the wall thickness of the corner portions 21c and 21d can be thinner than that of other portions. By providing thin-walled portions at the corner portions 21c and 21d, the cooling unit 20, which is an extruded component, can deform while maintaining its parallelogram shape when pressure is applied to its interior. Figure 8A As shown, corner 21c is formed by a thin-walled portion extending along deformed portion 21a. Corner 21c is thinner than deformed portion 21a. The shape of the thin-walled portion is not particularly limited. Figure 8B As shown, corner 21c can also be formed from a thin-walled portion extending along the Z direction. Or, as... Figure 8C As shown, the corner 21C can also be formed from a thin-walled portion extending along the X direction.

Claims

1. A cooler, which is alternately stacked with a battery to cool the battery, characterized in that, The aforementioned cooler has a cooling section disposed between the aforementioned batteries that are adjacent to each other in the stacking direction. The above-mentioned cooling section has: A flow path for the coolant to circulate; A first cooling surface, which is a cooling surface that contacts one of the aforementioned batteries; The second cooling surface is the cooling surface that contacts the other of the aforementioned batteries; A first protrusion protrudes from the back of the first cooling surface toward the back of the second cooling surface in the stacking direction; as well as The second protrusion protrudes from the back of the second cooling surface toward the back of the first cooling surface in the stacking direction. The aforementioned airflow routes are formed in the internal spaces where the back surfaces of the aforementioned cooling surfaces face each other. When the first cooling surface and the second cooling surface are in surface contact with the battery, inside the cooling section, the first protrusion and the second protrusion face each other in the stacking direction.

2. The cooler as claimed in claim 1, characterized in that, When the battery expands and the cooling surface deforms, causing the internal space to narrow, inside the cooling section, the first protrusion and the second protrusion abut against each other in a state where the back surfaces of the first cooling surface and the second cooling surface are separated.

3. The cooler as described in claim 2, characterized in that, With the first protrusion and the second protrusion in contact, the first protrusion and the second protrusion bear the load from the battery acting on the cooling surface, so that the flow path will not be crushed and blocked.

4. A method for manufacturing a battery pack, the battery pack comprising the cooler according to any one of claims 1 to 3, characterized in that, The above manufacturing method includes: In the insertion process, with a cooling device formed by a plurality of the aforementioned coolers disposed inside a housing housing a plurality of battery cells, the battery cells are inserted between adjacent coolers, with the cooling surfaces of the coolers facing each other; and In the deformation process, after the battery cells are inserted between the coolers, the internal pressure of the coolers is increased to deform the coolers so that the cooling surfaces come into contact with the battery cells. Inside the cooler before deformation during the insertion process, the first protrusion and the second protrusion do not face each other in the stacking direction. Inside the cooler after deformation in the above deformation process, the first protrusion and the second protrusion face each other in the stacking direction.

5. The method for manufacturing a battery pack as described in claim 4, characterized in that, The insertion process described above includes the following steps: placing the battery cell inside the housing at a position where the battery cell does not contact the cooling surface, while the cooler remains undeformed. The above-mentioned deformation process includes the following steps: bringing the cooling surface into contact with the battery cell to form a laminate of the cooler and the battery cell, and using the cooler to compress the battery cell along the lamination direction of the laminate. Inside the cooler after deformation in the above deformation process, the first protrusion and the second protrusion are in a separated state.

Images