Cooler and method for manufacturing a battery pack

Abstract

A cooler arranged in a housing that accommodates a battery comprises a cooling section positioned between adjacent batteries in a stacking direction. The cooling section includes a plurality of fins, each extending to connect a first inner surface of a first cooling surface to a second inner surface of a second cooling surface. The fins are deformable in response to changes in the distance between the first and second inner surfaces.The ribs comprise a pair of ribs configured to deform to move away from each other when the distance between the first inner surface and the second inner surface changes in a direction where the distance increases, and configured to deform to move towards each other when the distance between the first inner surface and the second inner surface changes in a direction where the distance decreases.

Description

BACKGROUND OF THE INVENTION 1. Field of the invention

[0001] The present invention relates to coolers and methods for manufacturing a battery pack. 2. Description of the state of the art

[0002] Japanese patent application JP 2024-509489A discloses a battery pack in which a cooling device is provided for cooling battery cells within a housing that accommodates a plurality of battery cells. In the configuration described in JP 2024-509489A, the cooling device comprises multiple coolers, and the coolers and battery cells are stacked alternately.

[0003] The Japanese patent application (translation of the PCT application) JP 2016 - 537 799 A discloses that a pre-bent fin is provided within a heat exchanger tube through which a coolant flows. The fin has a linear or curved shape that is inclined with respect to a major side face. SUMMARY OF THE INVENTION

[0004] In a structure where battery cells and coolers are stacked alternately, as in the configuration described in JP 2024-509489A, the battery cells expand during use, causing the coolers to deform and compress. In this case, the coolant channels inside the coolers become narrower under strong compression, resulting in a reduction in cooling capacity.

[0005] JP 2016-537799 A discloses that the heat exchanger tube is designed in a flat shape with two main side faces and edge sections. However, it does not disclose anything about changes in the thickness of the heat exchanger tube during battery operation, etc.

[0006] The present invention was developed taking into account the above circumstances and aims to provide a cooler and a method for manufacturing a battery pack that reduce the possibility of movement of the battery in the vertical direction when the thickness of the cooler is changed, and at the same time reduce the possibility of a collapse of a coolant channel during battery operation.

[0007] A cooler according to the present invention is a cooler arranged in a housing that accommodates a battery and configured to cool the battery. The cooler comprises a cooling section arranged in a stack of several batteries at a position between adjacent batteries in a stacking direction. The cooling section comprises: a channel through which coolant flows in a lateral direction perpendicular to the stacking direction; a first cooling surface in contact with one of the adjacent batteries; a second cooling surface in contact with the other of the adjacent batteries; and several fins, each extending to connect a first inner surface, which is a rear side of the first cooling surface, and a second inner surface, which is a rear side of the second cooling surface.The ribs are deformable in response to a change in the distance between the first and second inner surfaces. The ribs comprise a pair of ribs configured to deform to move away from each other when the distance between the first and second inner surfaces changes in a direction where the distance increases, and configured to deform to move towards each other when the distance between the first and second inner surfaces changes in a direction where the distance decreases.The pair of ribs is configured to come into contact with each other when the battery expands and the distance between the first inner surface and the second inner surface is reduced to a predetermined value, and in a state where the pair of ribs comes into contact with each other, they support each other so that the first inner surface and the second inner surface do not move any closer together.

[0008] 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 present invention. The method comprises an insertion step in which, in a state where a cooling device is arranged in a housing that accommodates several battery cells, each of the battery cells is inserted between corresponding adjacent coolers. The cooling device comprises a structure in which the coolers are arranged such that the cooling surfaces of the coolers face each other. The method further comprises a deformation step in which, after the insertion of each of the battery cells between the corresponding adjacent coolers, the internal pressure of the cooler is increased to deform the cooler so that the cooling surface comes into contact with the battery cell. In the insertion step, the pair of fins inside the cooler is in a separated state.The deformation step involves deforming the pair of ribs so that the pair of ribs moves away from each other, and shifting the cooling surface in the stacking direction while the cooler is deformed to increase the thickness of the cooler.

[0009] The present invention can reduce the possibility of a battery moving vertically when the thickness of a cooler changes, and at the same time reduce the possibility of a coolant channel collapsing during battery use. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The features and advantages as well as the technical and economic significance of exemplary embodiments of the invention are described below with reference to the accompanying drawings, in which the same reference numerals denote the same elements, showing: Fig. 1 schematically a battery pack according to one embodiment; Fig. 2 a cooling device; Fig. 3 a cooler; Fig. 4 a cooling section; Fig. 5 cross-sectional views, wherein part (a) shows the shape of the cooling section in an extruded state and part (b) shows the shape of the cooling section in a deformed state after pressure has been applied to the interior of the cooler in a deformation step; and Fig. 6 cross-sectional views, where part (a) shows the shape of the cooling section during battery use and part (b) shows a state in which the battery cells have expanded during battery use and each pair of ribs within the cooling section supports each other. DETAILED DESCRIPTION OF EXECUTION FORMS

[0011] A cooler and a method for manufacturing a battery pack according to one embodiment of the present invention are described in detail below. The present invention is not limited to the embodiment described below.

[0012] Fig. Figure 1 schematically shows a battery pack according to the embodiment. The battery pack 1 comprises a plurality of battery cells 2, a housing 3, and a cooling device 4. The battery pack 1 is mounted in an electric vehicle. The electric vehicle equipped with the battery pack 1 moves by supplying the electrical energy stored in the battery pack 1 to a traction motor.

[0013] The battery cells 2 are cells formed in a rectangular parallelepiped shape. Of the surfaces of each battery cell 2, the one with the largest area is a flat surface 2a. The battery cells 2 are arranged in the housing 3 such that their flat surfaces 2a point in the X direction. Inside the housing 3, the battery cells 2 are stacked in the X direction. The X direction corresponds to the stacking direction of the battery cells 2 stack.

[0014] Housing 3 is a battery pack housing that contains the battery cells 2 and the cooling device 4. Inside housing 3, the battery cells 2 form a battery module. Housing 3 can accommodate multiple battery modules.

[0015] The cooling device 4 cools the battery cells 2 with a coolant. The cooling device 4 comprises a radiator 20 and a pipe 30. As shown in Fig. As shown in Figure 2, the cooling device 4 is an integrated structure in which several coolers 20 are connected to a pair of pipes 30.

[0016] The coolers 20 are stacked alternately with the battery cells 2 and cool the battery cells 2. Each cooler 20 is made of an extruded metal profile. The coolers 20 extend in the Y direction. The Y direction is perpendicular to the X direction. The Y direction corresponds to the width direction of the battery cell 2. The width direction is perpendicular to the stacking direction. Each cooler 20 has cooling surfaces 20a, each of which is in contact with a corresponding battery cell 2. The cooling device 4 has a structure in which the cooling surfaces 20a of the coolers 20 face each other. Each cooling surface 20a touches the flat surface 2a of a corresponding battery cell 2.

[0017] The tubes 30 are rectangular tubes extending in the X direction. Each tube 30 is made from an extruded metal profile. The coolers 20 are connected to each tube 30.

[0018] As in Fig. As shown in Figure 1, in the finished state of the battery pack 1, a stack is formed within the housing 3 in which the coolers 20 and the battery cells 2 are stacked alternately in the X-direction, with the coolers 20 located at both ends of the stack in the stacking direction. The stacking direction corresponds to the X-direction. Since the battery cells 2 have a prismatic shape and the coolers 20 have a flat plate shape, each battery cell 2 is sandwiched between two coolers 20. The battery cells 2 and the coolers 20 are stacked such that the surfaces with the largest area of ​​their respective faces are in contact with each other. The cooling surfaces 20a comprise a first cooling surface 20b, which is in contact with one of the adjacent battery cells 2, and a second cooling surface 20c, which is in contact with the other of the adjacent battery cells 2.The first cooling surface 20b and the second cooling surface 20c can be referred to together as cooling surface(s) 20a, unless otherwise specified.

[0019] Each cooler 20 comprises a cooling section 21 and connecting sections 22. In each cooler 20, the cooling section 21 is a part that includes the cooling surfaces 20a, and the connecting sections 22 are parts that do not include the cooling surfaces 20a.

[0020] The cooling section 21 is arranged between adjacent battery cells 2 in the stacking direction and forms a stack together with the battery cells 2. As shown in Fig. As shown in Figure 3, each cooling section 21 is a multi-hole tube formed in a hollow flat plate shape and extending in the Y direction.

[0021] Within the cooling section 21, a channel 23, through which coolant flows, and several fins 24 are provided. The channel 23 extends along the Y-direction, and the coolant flows in the Y-direction. The interior of the cooling section 21 serves as the channel 23 for the coolant. The channel 23 is formed by the interior space between the opposing rear faces of the cooling surfaces 20a and is subdivided in the Z-direction by the fins 24. The Z-direction is perpendicular to the X- and Y-directions. The Z-direction corresponds to the vertical direction of the battery cells 2. The fins 24 extend such that they connect the opposing rear faces of the cooling surfaces 20a. The fins 24 are provided in the area where the cooling surfaces 20a extend in the Y-direction.

[0022] The connecting sections 22 are formed at both ends of the cooling section 21 in the Y-direction and are each connected to a corresponding pipe 30. Each connecting section 22 has a single channel that is not subdivided in the Z-direction. The channel of each cooler 20 is configured such that it branches off from the channel in the upstream connecting section 22 into the channels 23 in the cooling section 21 and merges from the cooling section 21 into the channel of the downstream connecting section 22. In the cooling device 4, the coolers 20 are arranged such that their cooling surfaces 20a face each other, and the connecting sections 22 of the coolers 20 are connected to the pipes 30.

[0023] Each tube 30 has several connection openings 31. Each tube 30 is formed by extrusion, and the connection openings 31 are opened by machining. Each connection opening 31 is an opening that opens in the Y direction, and the connecting section 22 of a corresponding cooler 20 is connected to each connection opening 31. The coolers 20 are connected to each tube 30 such that their connecting sections 22 fit into the connection openings 31.

[0024] A first end cap 32 and a second end cap 33 are connected to each of the tubes 30. The first end cap 32 is connected to the tube 30 to cover one open end of the tube 30 in the X direction. The second end cap 33 is connected to the tube 30 to cover the other open end of the tube 30 in the X direction. As shown in the Fig. 1 and Fig. As shown in Figure 2, a first pipe section 34 of one of the pipes 30 is connected to the first end cap 32, and a second pipe section 35 of the other pipe 30 is connected to the first end cap 32. The first pipe section 34 is an inlet-side pipe section. The coolant supplied to the cooling device 4 flows through the first pipe section 34 into the interior of the cooling device 4. The second pipe section 35 is an outlet-side pipe section. The coolant discharged from the cooling device 4 flows out of the cooling device 4 through the second pipe section 35.

[0025] In the cooling device 4, the cooling sections 21 are deformable such that their cooling surfaces 20a are displaced in the X-direction in response to the internal pressure in the cooler 20. The coolers 20 are configured to deform in such a way that their thickness increases in the X-direction. Fig. Figure 2 shows the coolers 20 before deformation, with their thickness remaining small in the X direction. Fig. Figure 1 shows the coolers 20 after deformation, where their thickness has increased in the X direction. The coolers 20 are manufactured in a thinner state than during use and soldered to the tubes 30.

[0026] As in Fig. As shown in Figure 3, the cooling section 21 comprises deformable sections 21a. The deformable sections 21a are sections that deform to change the thickness of the cooling section 21 in the X-direction. The deformable sections 21a are formed in a shape that is inclined in both the X-direction and the Z-direction. The deformable sections 21a include one deformable section 21a that is formed in an inverted V-shape on one side in the Z-direction and one deformable section 21a that is formed in a V-shape on the other side in the Z-direction.

[0027] As in Fig. As shown in Figure 4, the cooling section 21 has a hexagonal outer shape in its extruded state. The outer shape of the cooling section 21 is defined by the cooling surfaces 20a and the deformable sections 21a. The ribs 24 are provided within the cooling section 21.

[0028] Each rib 24 extends such that it connects a first inner surface 21b and a second inner surface 21c. The first inner surface 21b is the back side of the first cooling surface 20b, and the second inner surface 21c is the back side of the second cooling surface 20c. Each rib 24 includes a section that projects relatively in the Z-direction between the first inner surface 21b and the second inner surface 21c. Each 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 sections 21a and the ribs 24 deform. Fig. Figure 4 shows the shape of the deformable sections 21a and the ribs 24 before deformation.

[0029] Each rib 24 comprises a pair of ribs, i.e., a first rib 41 with a first contact section 25 and a second rib 42 with a second contact section 26. The in Fig. The cooling section 21 shown in Figure 4 is provided with two pairs of ribs 24.

[0030] The first rib 41 is connected to the first inner surface 21b at a first connection point 51 and to the second inner surface 21c at a second connection point 52. The first contact section 25 is located closer to the second rib 42 than the first connection point 51 and the second connection point 52. The section between the first connection point 51 and the first contact section 25 is linear and inclined with respect to the X-direction. The section between the second connection point 52 and the first contact section 25 is also linear and inclined with respect to the X-direction.

[0031] The second rib 42 is connected to the first inner surface 21b at a third connection point 53 and to the second inner surface 21c at a fourth connection point 54. The second contact section 26 is located closer to the first rib 41 than the third connection point 53 and the fourth connection point 54. The section between the third connection point 53 and the second contact section 26 is formed in a linear shape that is inclined with respect to the X-direction. The section between the fourth connection point 54 and the second contact section 26 is also formed in a linear shape that is inclined with respect to the X-direction.

[0032] In each pair of ribs 24, the distance between the first connection point 51 and the third connection point 53 is less than the sum of the distance from the first connection point 51 to the first contact section 25 and the distance from the third connection point 53 to the second contact section 26. Similarly, in each pair of ribs 24, the distance between the second connection point 52 and the fourth connection point 54 is less than the sum of the distance from the second connection point 52 to the first contact section 25 and the distance from the fourth connection point 54 to the second contact section 26.

[0033] As in Fig. As shown in Figure 4, in the extruded state of the cooling section 21, the first rib 41 and the second rib 42 are separated from each other. The first rib 41 and the second rib 42 face each other in the Z-direction, with their respective contact sections close together. In each pair of ribs 24, the first contact section 25 and the second contact section 26 can come into contact with each other. When the first contact section 25 and the second contact section 26 come into contact with each other, the two ribs 24 touch.

[0034] As in the Fig. 5 and Fig. As shown in Figure 6, each rib 24 comprises 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 an increasing direction, and that deform to move towards each other when the distance between the first inner surface 21b and the second inner surface 21c changes in a decreasing direction. As the battery cells 2 expand and the distance between the first inner surface 21b and the second inner surface 21c decreases to a predetermined value, each pair of ribs 24 comes into contact with each other and supports each other in this contact state, preventing the first inner surface 21b and the second inner surface 21c from moving any closer together. The predetermined value is set to the distance corresponding to the state in which the first inner surface 21b and the second inner surface 21c are separated.

[0035] The method for manufacturing the battery pack 1 comprises a joining step, a placement step, an insertion step, and a deformation step. In this method, after the battery cells 2 and the cooling device 4 are housed in the casing 3, pressure is applied to the interior of each cooler 20 to expand the cooling sections 21, thereby bringing the cooling sections 21 into close contact with the battery cells 2.

[0036] The joining step is a step for connecting the coolers 20 to the pipes 30. In the joining step, the cooling device 4 is formed as an integral structure by connecting its components so that the cooling surfaces 20a of the coolers 20 face each other. The cooling device 4 produced by the joining step is in Fig. 2 shown.

[0037] The placement step is a step to install the cooling device 4 as an integral structure in the housing 3. In the placement step, the cooling device 4 is installed in the housing 3, in which the battery cells 2 are not yet installed.

[0038] The insertion step is a step for inserting each battery cell 2 between correspondingly adjacent coolers 20. In the insertion step, with the cooling device 4 arranged in the housing 3 such that the coolers 20 face each other, each battery cell 2 is inserted between correspondingly adjacent coolers 20. When each battery cell 2 is inserted, there is a gap between the battery cell 2 and each of its correspondingly adjacent coolers 20. Before the battery cells 2 are inserted, the coolers 20 are in a thin state. The coolers 20 are extruded in this thin form. In the insertion step, with the coolers 20 undeformed, each battery cell 2 is placed at a position within the space between the corresponding opposing cooling surfaces 20a such that the flat surfaces 2a do not touch the cooling surfaces 20a.During the insertion step, each pair of ribs 24 within each cooler 20 is in a separated state.

[0039] The deformation step is a step to expand the cooling sections 21 by increasing the internal pressure of the coolers 20. In the deformation step, after each battery cell 2 has been inserted between the corresponding coolers 20, the internal pressure of the coolers 20 is increased to deform the coolers 20 so that the cooling surfaces 20a come into contact with the battery cells 2.

[0040] In the deformation step, after the cooling device 4 has been inserted into the housing 3, the second pipe section 35 is closed by a valve or the like, and coolant is fed from the first pipe section 34 into the interior of the coolers 20 via a pump or the like, thereby pressurizing the interior of the coolers 20. As the internal pressure of the coolers 20 increases, the deformable sections 21a and the fins 24 are deformed such that the channels 23 inside the coolers 20 expand in the X direction.

[0041] When pressure is applied to the interior of the coolers 20 during the deformation step, the coolers 20 begin to expand. As the coolers 20 are deformed, increasing their thickness, each pair of fins 24 is deformed to move away from each other, thus displacing the cooling surfaces 20a in the stacking direction. The shapes of the deformable sections 21a and the fins 24 allow the cooling sections 21a to expand in the X-direction, preventing the cooling surfaces 20a from moving in the Z-direction. If the cooling surfaces 20a were to move in the Z-direction during the deformation step, it would cause the battery cells 2, which are in contact with the cooling surfaces 20a, to be displaced in the Z-direction. This would result in a positional misalignment of the battery cells 2 in the Z-direction.To remedy this, each cooling section 21 is provided with ribs 24 whose shape allows the cooling surfaces 20a to be moved in the X direction without causing a displacement of the cooling surfaces 20a in the Z direction.

[0042] As in part (a) of Fig. As shown in Figure 5, the cooling section 21, in a state prior to the deformation of the deformable sections 21a by the deformation step, has a small thickness in the X-direction. The thickness of the cooling section 21 prior to deformation is W. As shown in part (b) of Fig. As shown in Figure 5, in the state after the deformation of the deformable sections 21a by the deformation step, the thickness of the cooling sections 21 in the X-direction is greater than before the deformation. The thickness of the cooling section 21 after deformation is W1. When pressure is applied to the interior of the cooler 20, the cooler 20 expands completely. In the deformation step, the cooling section 21 is deformed to increase its thickness in the X-direction, thereby bringing each of the cooling surfaces 20a into close contact with a corresponding battery cell 2.

[0043] In the deformation step, the coolers 20 are deformed so that each cooling surface 20a comes into contact with the flat surface 2a of a corresponding battery cell 2. After each battery cell 2 has been inserted into the space between the corresponding opposing cooling surfaces 20a, coolant is pumped to the first pipe section 34, thereby increasing the internal pressure of the coolers 20. As the internal pressure of the coolers 20 increases and the coolers 20 are deformed so that the thickness of the cooling sections 21 increases in the X direction, each of the cooling surfaces 20a can be brought into close contact with a corresponding flat surface 2a. In the deformation step, each cooling surface 20a is brought into contact with a corresponding battery cell 2 to form a stack of the coolers 20 and the battery cells 2, and the battery cells 2 are compressed by the coolers 20 in the stacking direction.

[0044] As in part (a) of Fig. As shown in Figure 6, the thickness of the cooling section is 21 W1 when each pair of fins 24 remains separated during battery operation. As shown in part (b) of Fig. As shown in Figure 6, the thickness of the cooling section 21 decreases in the X-direction when the cooling section 21 is compressed due to the expansion of the battery cells 2 in the X-direction. When each pair of fins 24 comes into contact with each other due to the expansion of the battery cells 2, the thickness of the cooling section 21 is W2. The thickness W2 is smaller than the thickness W1.

[0045] As described above, according to the present embodiment, even if the battery cells 2 expand during use, each pair of fins 24 provided within each cooling section 21 remains in contact with each other. This reduces the possibility of the channels 23 collapsing completely. Consequently, the cross-sectional area of ​​the channels 23 can be maintained and cooling performance ensured.

[0046] 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 can also be used in which the battery cells 2 are arranged side by side in the Y direction.

[0047] The shape of rib 24 is not based on the one in Fig. The linear form shown in Figure 4, etc., is limited. The ribs 24 can have a curved shape. Likewise, the shape of the deformable sections 21a is not limited to the V-shape or the inverted V-shape and can be a curved shape.

[0048] The first contact section 25 and the second contact section 26 are not limited to shapes that establish line contact with each other. The first contact section 25 and the second contact section 26 can be shapes that establish surface contact with each other.

[0049] The number of contact sections provided on rib 24 is not particularly limited. The first rib 41 can comprise a plurality of first contact sections 25 between the first connection point 51 and the second connection point 52. The second rib 42 can comprise a plurality of second contact sections 26 between the third connection point 53 and the fourth connection point 54. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2024 - 509 489 A [0002, 0004] JP 2016 - 537 799 A [0003, 0005]

Claims

[1] A cooler arranged in a housing that accommodates a battery and configured to cool the battery, the cooler comprising a cooling section arranged in a stack of multiple batteries at a position between adjacent batteries in a stacking direction of the stack, wherein: the cooling section includes a channel through which coolant flows in a lateral direction perpendicular to the stacking direction, a first cooling surface that is in contact with one of the neighboring batteries, a second cooling surface that is in contact with the other of the adjacent batteries, and several ribs, each extending to connect a first inner surface, which is a back side of the first cooling surface, and a second inner surface, which is a back side of the second cooling surface, wherein the ribs are deformable in response to a change in the distance between the first inner surface and the second inner surface; the ribs comprise a pair of ribs configured to deform to move away from each other when the distance between the first inner surface and the second inner surface changes in a direction where the distance increases, and configured to deform to move towards each other when the distance between the first inner surface and the second inner surface changes in a direction where the distance decreases; and the pair of ribs is configured to come into contact with each other when the battery expands and the distance between the first inner surface and the second inner surface is reduced to a predetermined value, and in a state where the pair of ribs comes into contact with each other, they support each other so that the first inner surface and the second inner surface do not move any closer together. [2] Cooler according to claim 1, wherein: the pair of ribs a first rib with a first contact section, and a second rib arranged so that it faces the first rib and has a second contact section configured to come into contact with the first contact section; the first contact section is located closer to the second rib than a first connection point where the first rib is connected to the first inner surface, and a second connection point where the first rib is connected to the second inner surface; the second contact section is located closer to the first rib than a third connection point where the second rib is connected to the first inner surface, and a fourth connection point where the second rib is connected to the second inner surface; and the pair of ribs is configured so that they come into contact with each other when the first contact section and the second contact section come into contact with each other. [3] Cooler according to claim 2, wherein a distance between the first connection point and the third connection point is less than the sum of a distance from the first connection point to the first contact section and a distance from the third connection point to the second contact section. [4] Cooler according to claim 3, wherein a distance between the second connection point and the fourth connection point is less than the sum of a distance from the second connection point to the first contact section and a distance from the fourth connection point to the second contact section. [5] Method for manufacturing a battery pack with the cooler according to any one of claims 1 to 4, wherein the method comprises: an insertion step in which, in a state where a cooling device is arranged in a housing that accommodates multiple battery cells, each of the battery cells is inserted between corresponding adjacent coolers, the cooling device comprising a structure in which the coolers are arranged such that the cooling surfaces of the coolers face each other; and a deformation step in which, after inserting each of the battery cells between the corresponding adjacent coolers, the internal pressure of the cooler is increased in order to deform the cooler so that the cooling surface comes into contact with the battery cell, wherein: During the insertion step, the pair of fins inside the cooler is in a separated state; and The deformation step includes deforming the pair of ribs so that the pair of ribs moves away from each other, and shifting the cooling surface in the stacking direction while the cooler is deformed to increase the thickness of the cooler.

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