Method for manufacturing a cooler and battery pack

Abstract

To prevent the coolant flow path from being crushed when the battery is in use, while also preventing the battery from moving vertically when the thickness of the cooler changes. [Solution] A cooler disposed inside a case housing batteries, having a cooling section disposed between adjacent batteries in the stacking direction, the cooling section having a plurality of ribs that extend to connect the first inner surface of the first cooling surface and the second inner surface of the second cooling surface and are deformable in response to a change in the distance between the first inner surface and the second inner surface, the plurality of ribs include a pair of ribs that deform to move away from each other when the distance between the first inner surface and the second inner surface changes in the direction of widening, and deform to move closer to each other when the distance between the first inner surface and the second inner surface changes in the direction of narrowing, the pair of ribs come into contact with each other when the batteries expand and the distance between the first inner surface and the second inner surface narrows to a predetermined amount, and in that contact state the ribs support each other so that the first inner surface and the second inner surface do not come any closer together.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a cooler and a battery pack.

Background Art

[0002] Patent Document 1 discloses a battery pack in which a cooling device for cooling battery cells is provided inside a case that houses a plurality of battery cells. In the configuration described in Patent Document 1, the cooling device has a plurality of coolers, and the plurality of coolers and the plurality of battery cells are alternately stacked.

[0003] Patent Document 2 discloses providing a rib that has been bent in advance inside a heat exchange tube through which a coolant flows. The shape of the rib is a linear shape or a curved shape that is inclined with respect to the main surface.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a structure in which battery cells and coolers are alternately stacked as in the configuration described in Patent Document 1, during use, when the battery cells expand, the coolers are deformed so as to be compressed. In this case, when the coolers are greatly compressed, the flow path of the coolant provided inside the coolers becomes narrow, and the cooling performance deteriorates.

[0006] Although Patent Document 2 discloses that the heat exchange tube is formed in a flat shape including two main surfaces and an edge portion, it does not disclose anything about the change in the thickness of the heat exchange tube during battery use or the like.

[0007] The present invention has been made in view of the above circumstances, and aims to provide a cooler and a method for manufacturing a battery pack that can prevent the coolant flow path from being crushed when the battery is in use, and prevent the battery from moving in the height direction when the thickness of the cooler changes. [Means for solving the problem]

[0008] The cooler according to the present invention is a cooler disposed inside a case housing a battery and for cooling the battery, and has a cooling section disposed between adjacent batteries in the stacking direction of a stack of batteries, the cooling section has a flow path through which a cooling liquid flows in a width direction perpendicular to the stacking direction, a first cooling surface that contacts one of the batteries, a second cooling surface that contacts the other of the batteries, and an extension that connects the first inner surface which is the back surface of the first cooling surface and the second inner surface which is the back surface of the second cooling surface, and the distance between the first inner surface and the second inner surface The battery has a plurality of ribs that are deformable in response to changes, the plurality of ribs include a pair of ribs that deform to move away from each other when the distance between the first inner surface and the second inner surface changes in the direction of widening, and deform to move closer to each other when the distance between the first inner surface and the second inner surface changes in the direction of narrowing, the pair of ribs come into contact with each other when the battery expands and the distance between the first inner surface and the second inner surface narrows to a predetermined amount, and the ribs support each other in that contact state so that the first inner surface and the second inner surface do not come any closer together.

[0009] A method for manufacturing a battery pack according to the present invention is a method for manufacturing a battery pack comprising the cooler according to the above invention, wherein a cooling device having a structure in which the coolers are arranged so that their cooling surfaces face each other is installed inside a case that houses a plurality of battery cells, the method comprising an insertion step of inserting the battery cells between adjacent coolers, and a deformation step of, after the battery cells have been inserted between the coolers, deforming the cooler so that the pressure inside the cooler is increased and the cooling surface comes into contact with the battery cells, wherein, inside the cooler during the insertion step, the pair of ribs are separated from each other, and the deformation step is characterized in that, in the process of deforming the cooler to increase its thickness, the pair of ribs are deformed so that they separate from each other and the cooling surface is displaced only in the stacking direction. [Effects of the Invention]

[0010] In this invention, it is possible to prevent the cooling liquid flow path from being crushed when the battery is in use, while also preventing the battery from moving in the height direction when the thickness of the cooler changes. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic diagram showing the battery pack in the embodiment. [Figure 2] This is a diagram illustrating a cooling system. [Figure 3] This is a schematic diagram to explain a condenser. [Figure 4] This is a cross-sectional view illustrating the cooling section. [Figure 5] Figure 5(a) is a cross-sectional view illustrating the shape of the cooling section in the extruded state, and Figure 5(b) is a cross-sectional view illustrating the shape of the cooling section after the cooler has been deformed by the deformation process due to the pressure applied inside the cooler. [Figure 6]Figure 6(a) is a cross-sectional view illustrating the shape of the cooling section when the battery is in use, and Figure 6(b) is a cross-sectional view illustrating the state in which the battery cell expands when the battery is in use, causing a pair of ribs to support each other inside the cooling section. [Modes for carrying out the invention]

[0012] The following describes in detail the methods for manufacturing the cooler and battery pack according to embodiments of the present invention. However, the present invention is not limited to the embodiments described below.

[0013] Figure 1 is a schematic diagram of a battery pack in an embodiment. The battery pack 1 comprises a plurality of battery cells 2, a case 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 runs by supplying the power stored in the battery pack 1 to a motor for driving.

[0014] The battery cell 2 is a battery formed in the shape of a rectangular parallelepiped. Of the surfaces of the battery cell 2, the surface with the largest area is the flat surface 2a. The battery cell 2 is placed inside the case 3 with the flat surface 2a facing the X direction. Inside the case 3, multiple battery cells 2 are stacked in the X direction. The X direction is the same direction as the stacking direction of the stacked body of multiple battery cells 2.

[0015] Case 3 is a battery pack case that houses the battery cells 2 and the cooling device 4. Inside Case 3, multiple battery cells 2 constitute a battery module. Case 3 can accommodate multiple battery modules.

[0016] The cooling device 4 cools the battery cell 2 with a cooling liquid. The cooling device 4 comprises a cooler 20 and a pipe 30. As shown in Figure 2, the cooling device 4 is an integrated structure in which multiple coolers 20 are joined to a pair of pipes 30.

[0017] The cooler 20 is stacked alternately with the battery cells 2 to cool the battery cells 2. The cooler 20 is composed of a metal extruded material. The cooler 20 extends in the Y direction. The Y direction is a direction orthogonal to the X direction. The Y direction is the same direction as the width direction of the battery cell 2. The width direction is a direction orthogonal to the stacking direction. The cooler 20 has a cooling surface 20a that contacts the battery cell 2. The cooling device 4 has a structure in which the coolers 20 face each other with the cooling surfaces 20a. The cooling surface 20a contacts the flat surface 2a of the battery cell 2.

[0018] The pipe 30 is a square pipe extending in the X direction. The pipe 30 is composed of a metal extruded material. A plurality of coolers 20 are connected to the pipe 30.

[0019] As shown in FIG. 1, in the completed state of the battery pack 1, a laminate is formed inside the case 3 in which a plurality of coolers 20 and a plurality of battery cells 2 are alternately stacked in the X direction, and the coolers 20 are located on both ends in the stacking direction of the laminate. The stacking direction is the same direction as the X direction. Since the battery cell 2 is square and the cooler 20 is flat, one battery cell 2 is sandwiched between two coolers 20. The battery cell 2 and the cooler 20 are stacked so that the surfaces with the largest area among the plurality of surfaces contact each other. The cooling surface 20a includes a first cooling surface 20b that contacts one of the adjacent battery cells 2 and a second cooling surface 20c that contacts the other of the adjacent battery cells 2. When the first cooling surface 20b and the second cooling surface 20c are not particularly distinguished, it is described as the cooling surface 20a.

[0020] The cooler 20 has a cooling part 21 and a connecting part 22. In the cooler 20, the cooling part 21 is a part including the cooling surface 20a, and the connecting part 22 is a part not including the cooling surface 20a.

[0021] The cooling part 21 is disposed between adjacent battery cells 2 in the stacking direction and forms a laminate together with the battery cells 2. As shown in FIG. 3, the cooling part 21 is formed in a hollow flat plate shape and is a multi-hole pipe extending in the Y direction.

[0022] The cooling section 21 is provided with a flow path 23 through which coolant flows and a plurality of ribs 24. The flow path 23 extends along the Y direction, and the coolant flows in the Y direction. The internal space of the cooling section 21 is the flow path 23 for the coolant. The flow path 23 is formed by the internal space where the back surfaces of the cooling surface 20a face each other, and is partitioned in the Z direction by the ribs 24. The Z direction is perpendicular to the X and Y directions. The Z direction is the same direction as the height direction of the battery cell 2. The ribs 24 extend so as to connect the back surfaces of the cooling surface 20a. The ribs 24 are provided in the region where the cooling surface 20a extends in the Y direction.

[0023] The connection sections 22 are formed on both ends of the cooling section 21 in the Y direction and are connected to the pipe 30. The connection sections 22 have a single flow path that is not partitioned in the Z direction. The flow path of the cooler 20 is formed to branch from the flow path of the upstream connection section 22 into multiple flow paths 23 of the cooling section 21, and then merge at the flow path of the downstream connection section 22 from the cooling section 21. In the cooling device 4, the coolers 20 are arranged so that their cooling surfaces 20a face each other, and the connection sections 22 of the coolers 20 are joined to the pipe 30.

[0024] The pipe 30 has multiple connection ports 31. The pipe 30 is formed by extrusion molding, and the connection ports 31 are opened by machining. The connection ports 31 are openings that open in the Y direction, and the connection portion 22 of the cooler 20 is connected to them. The cooler 20 and the pipe 30 are joined when the connection portion 22 is fitted into the connection ports 31.

[0025] 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 so as to cover one open end of the pipe 30 in the X direction. The second end cap 33 is joined to the pipe 30 so as to cover the other open end of the pipe 30 in the X direction. As shown in Figures 1 and 2, in the pair of pipes 30, a first pipe section 34 is joined to one of the first end caps 32, and a second pipe section 35 is joined to the other first end cap 32. The first pipe section 34 is the inlet pipe section. The 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 pipe section. The coolant discharged from the cooling device 4 flows out to the outside of the cooling device 4 from the second pipe section 35.

[0026] In the cooling device 4, the cooling section 21 is deformable so as to displace the cooling surface 20a in the X direction in response to the pressure inside the cooler 20. The cooler 20 is configured to be deformable so that its thickness in the X direction increases. Figure 2 shows the cooler 20 before deformation, with its thickness in the X direction remaining thin. Figure 1 shows the cooler 20 after deformation, with its thickness in the X direction increased. The cooler 20 is manufactured in a thinner state than when in use and brazed to the pipe 30.

[0027] As shown in Figure 3, the cooling section 21 has a deformable section 21a. The deformable section 21a is a part that deforms so that the thickness of the cooling section 21 in the X direction changes. The deformable section 21a is formed in a shape that is inclined with respect to the X direction and inclined with respect to the Z direction. The deformable section 21a includes a deformable section 21a formed in an inverted V shape on one side in the Z direction and a deformable section 21a formed in a V shape on the other side in the Z direction.

[0028] As shown in Figure 4, the cooling section 21 in its extruded state has a hexagonal shape. The outer shape of the cooling section 21 consists of a cooling surface 20a and a deformed section 21a. Multiple ribs 24 are provided inside the cooling section 21.

[0029] The rib 24 extends to connect the first inner surface 21b, which is the back surface of the first cooling surface 20b, and the second inner surface 21c, which is the back surface of the second cooling surface 20c. The rib 24 includes a portion that protrudes relatively in the Z direction between the first inner surface 21b and the second inner surface 21c. The rib 24 is deformable in response to changes in the distance between the first inner surface 21b and the second inner surface 21c. In the cooling section 21, the deformable portion 21a and the rib 24 deform. Figure 4 shows the shapes of the deformable portion 21a and the rib 24 before deformation.

[0030] Each of the multiple ribs 24 includes a pair of ribs consisting of a first rib 41 having a first contact portion 25 and a second rib 42 having a second contact portion 26. In the cooling section 21 illustrated in Figure 4, two sets of these pairs of ribs 24 are provided.

[0031] The first rib 41 is connected to the first inner surface 21b at the first connection point 51 and to the second inner surface 21c at the second connection point 52. The first abutment portion 25 is located on the second rib 42 side of the first connection point 51 and the second connection point 52. The portion between the first connection point 51 and the first abutment portion 25 is formed in a linear shape inclined with respect to the X direction. The portion between the second connection point 52 and the first abutment portion 25 is formed in a linear shape inclined with respect to the X direction.

[0032] The second rib 42 is connected to the first inner surface 21b at the third connection point 53 and to the second inner surface 21c at the fourth connection point 54. The second abutment portion 26 is located closer to the first rib 41 than the third connection point 53 and the fourth connection point 54. The portion between the third connection point 53 and the second abutment portion 26 is formed in a linear shape inclined with respect to the X direction. The portion between the fourth connection point 54 and the second abutment portion 26 is formed in a linear shape inclined with respect to the X direction.

[0033] In a pair of ribs 24, the length between the first connection point 51 and the third connection point 53 is shorter than the sum of the length from the first connection point 51 to the first contact portion 25 and the length from the third connection point 53 to the second contact portion 26. In a pair of ribs 24, the length between the second connection point 52 and the fourth connection point 54 is shorter than the sum of the length from the second connection point 52 to the first contact portion 25 and the length from the fourth connection point 54 to the second contact portion 26.

[0034] As shown in Figure 4, in the extruded cooling section 21, the first rib 41 and the second rib 42 are spaced apart. The first rib 41 and the second rib 42 face each other in the Z direction with their contact portions close together. The first contact portion 25 and the second contact portion 26 of the pair of ribs 24 can come into contact with each other. When the first contact portion 25 and the second contact portion 26 come into contact, the pair of ribs 24 come into contact with each other.

[0035] As shown in Figures 5 and 6, the rib 24 includes a pair of ribs that deform to move away from each other when the distance between the first inner surface 21b and the second inner surface 21c changes in the direction of widening, and deform to move closer to each other when the distance between the first inner surface 21b and the second inner surface 21c changes in the direction of narrowing. The pair of ribs 24 come into contact with each other when the battery cell 2 expands and the distance between the first inner surface 21b and the second inner surface 21c narrows to a predetermined amount, and in that contact state, the ribs support each other to prevent the first inner surface 21b and the second inner surface 21c from coming any closer together. The predetermined amount is set to an amount corresponding to the state in which the first inner surface 21b and the second inner surface 21c are separated.

[0036] The manufacturing method for the battery pack 1 includes a joining step, an installation step, an insertion step, and a deformation step. In this manufacturing method, after housing the battery cell 2 and the cooling device 4 in the case 3, the cooling section 21 is expanded by applying internal pressure to the cooler 20, causing the cooling section 21 to be in close contact with the battery cell 2.

[0037] The joining process involves joining multiple coolers 20 to a pair of pipes 30. In the joining process, the components are joined so that the coolers 20 face each other on the cooling surface 20a, thereby forming a single integrated cooling device 4. The cooling device 4 manufactured by the joining process is shown in Figure 2.

[0038] The installation process involves installing the integrated cooling device 4 inside the case 3. In the installation process, the cooling device 4 is installed inside the case 3 while the battery cells 2 are not yet installed.

[0039] The insertion process involves inserting battery cells 2 between two coolers 20. In the insertion process, with the cooling device 4 configured so that the coolers 20 face each other installed inside the case 3, battery cells 2 are inserted between adjacent coolers 20. When inserting the battery cells 2, there is a clearance between the cooler 20 and the battery cells 2. Before inserting the battery cells 2, the coolers 20 are thin. The coolers 20 are extruded into this thin shape. In the insertion process, with the coolers 20 in an undeformed state, the battery cells 2 are placed in a position where the flat surface 2a and the cooling surface 20a do not come into contact within the space where the cooling surfaces 20a face each other. Inside the cooler 20 during the insertion process, a pair of ribs 24 are spaced apart.

[0040] The deformation process involves increasing the internal pressure of the cooler 20 to expand the cooling section 21. In the deformation process, after the battery cells 2 are inserted between the coolers 20, the internal pressure of the cooler 20 is increased to deform the cooler 20 so that the cooling surface 20a comes into contact with the battery cells 2.

[0041] In the deformation process, after the cooling device 4 is placed inside the case 3, the second pipe section 35 is closed with a valve or the like, and the cooling liquid inside the cooler 20 is supplied from the first pipe section 34 side by a pump or the like, thereby pressurizing the inside of the cooler 20. As the pressure inside the cooler 20 increases, the deformation section 21a and the rib 24 are deformed so that the flow path 23 inside the cooler 20 expands in the X direction.

[0042] When pressure is applied to the inside of the cooler 20 during the deformation process, the cooler 20 begins to expand. In the process of deforming the cooler 20 to increase its thickness, a pair of ribs 24 are deformed to separate from each other, causing the cooling surface 20a to be displaced only in the stacking direction. The shape of the deformed part 21a and the ribs 24 allows the cooling part 21 to expand in the X direction while preventing the cooling surface 20a from moving in the Z direction. If the cooling surface 20a moves in the Z direction during the deformation process, it will move the battery cell 2 that the cooling surface 20a is in contact with in the Z direction. In this case, the battery cell 2 will be misaligned in the Z direction. To prevent this, the cooling part 21 is provided with ribs 24 with a shape that allows the cooling surface 20a to be displaced in the X direction while preventing it from being displaced in the Z direction.

[0043] As shown in Figure 5(a), before deformation of the deformable portion 21a by the deformation process, the thickness of the cooling portion 21 in the X direction is thin. The thickness of the cooling portion 21 before deformation is thickness W. As shown in Figure 5(b), after deformation of the deformable portion 21a by the deformation process, the thickness of the cooling portion 21 in the X direction becomes thicker than before deformation. The thickness of the cooling portion 21 after deformation is thickness W1. When pressure is applied inside the cooler 20, the cooler 20 expands to its fullest extent. In the deformation process, the cooling portion 21 is deformed to increase its thickness in the X direction, thereby bringing the cooling surface 20a into close contact with the battery cell 2.

[0044] In the deformation process, the cooler 20 is deformed to bring the cooling surface 20a into contact with the flat surface 2a of the battery cell 2. After the battery cell 2 is inserted into the space between the opposing cooling surfaces 20a, coolant is supplied from the pump to the first pipe section 34 to increase the internal pressure of the cooler 20. As the internal pressure of the cooler 20 increases and it deforms so that the thickness of the cooling section 21 in the X direction increases, the cooling surface 20a can be brought into close contact with the flat surface 2a. The deformation process brings the cooling surface 20a into contact with the battery cell 2 to form a laminate in which the cooler 20 and the battery cell 2 are stacked, and the cooler 20 compresses the battery cell 2 in the stacking direction of the laminate.

[0045] As shown in Figure 6(a), when the battery is in use, the thickness of the cooling section 21 is W1 when the pair of ribs 24 are separated. As shown in Figure 6(b), when the cooling section 21 is compressed in the X direction due to the expansion of the battery cell 2, the thickness of the cooling section 21 in the X direction becomes thinner. When the pair of ribs 24 are in contact due to the expansion of the battery cell 2, the thickness of the cooling section 21 is W2. Thickness W2 is thinner than thickness W1.

[0046] As described above, according to this embodiment, even if the battery cell 2 expands during use, the pair of ribs 24 provided inside the cooling section 21 make contact with it, preventing the flow path 23 from collapsing completely. This ensures that the flow path cross-sectional area of ​​the flow path 23 is maintained and that cooling performance is ensured.

[0047] The number of battery cells 2 is not particularly limited. The number of battery cells 2 stacked in the X direction is not limited. A structure in which multiple battery cells 2 are arranged side by side in the Y direction is also possible.

[0048] Furthermore, the shape of the rib 24 is not limited to the straight shape exemplified in Figure 4, etc. The rib 24 may also have a curved shape. Similarly, the shape of the deformed portion 21a is not limited to a V-shape or an inverted V-shape, and may also be curved.

[0049] Furthermore, the first contact portion 25 and the second contact portion 26 are not limited to a line contact shape. They may also be surface contact shapes.

[0050] Furthermore, the number of contact points provided on the rib 24 is not particularly limited. The first rib 41 may have multiple first contact points 25 between the first connection point 51 and the second connection point 52. The second rib 42 may have multiple second contact points 26 between the third connection point 53 and the fourth connection point 54. [Explanation of symbols]

[0051] 1 Battery pack 2 battery cells 3 cases 4 Cooling device 20 Cooler 20b 1st cooling surface 20c 2nd cooling surface 21 Cooling section 23 Flow channels 24 Ribs 25 1st contact part 26 Second contact part 41. First Rib 42. Second Rib

Claims

1. A cooler, which is placed inside a case that houses a battery and cools the battery, A stack of the batteries is provided with a cooling section located between adjacent batteries in the stacking direction of the stack. The cooling unit is A flow path through which coolant flows in the width direction perpendicular to the stacking direction, A first cooling surface that contacts one of the aforementioned batteries, A second cooling surface that contacts the other of the aforementioned batteries, It has a plurality of ribs that extend to connect the first inner surface, which is the back surface of the first cooling surface, and the second inner surface, which is the back surface of the second cooling surface, and which are deformable in accordance with a change in the distance between the first inner surface and the second inner surface, The plurality of ribs include a pair of ribs that deform to move away from each other when the distance between the first inner surface and the second inner surface changes in a direction that widens, and deform to move closer to each other when the distance between the first inner surface and the second inner surface changes in a direction that narrows, The pair of ribs will come into contact with each other when the battery expands and the distance between the first inner surface and the second inner surface narrows to a predetermined amount, and in that contact state, the ribs will support each other to prevent the first inner surface and the second inner surface from coming any closer together. A cooler characterized by the following features.

2. The pair of ribs are, A first rib having a first contact portion, It includes a second rib that is positioned opposite the first rib and has a second contact portion that contacts the first contact portion, The first contact portion is located on the second rib side of the first connection point where the first rib is connected to the first inner surface, and the second connection point where the first rib is connected to the second inner surface. The second contact portion is located on the first rib side of the third connection point where the second rib is connected to the first inner surface, and the fourth connection point where the second rib is connected to the second inner surface. When the first contact portion and the second contact portion come into contact, the pair of ribs come into contact with each other. The cooler according to feature 1.

3. The length between the first connection point and the third connection point is shorter than the sum of the length from the first connection point to the first contact portion and the length from the third connection point to the second contact portion. The cooler according to feature 2.

4. The length between the second connection point and the fourth connection point is shorter than the sum of the length from the second connection point to the first contact point and the length from the fourth connection point to the second contact point. The cooler according to feature 3.

5. A method for manufacturing a battery pack comprising a cooler according to any one of claims 1 to 4, In a cooling device having a structure in which the coolers are arranged so that their cooling surfaces face each other, the cooling device is installed inside a case that houses multiple battery cells, and the process includes an insertion step of inserting the battery cells between adjacent coolers, After the battery cells are inserted between the coolers, a deformation step is performed to deform the coolers by increasing the internal pressure of the coolers so that the cooling surface comes into contact with the battery cells. Includes, In the insertion process, the pair of ribs are separated from each other inside the cooler. The deformation step includes a step of deforming the cooler so that its thickness is increased, by deforming the pair of ribs so that they separate from each other, thereby displacing the cooling surface only in the stacking direction. A method for manufacturing a battery pack characterized by the following:

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