Battery pack and manufacturing method thereof

Abstract

To provide a battery pack capable of increasing a load density of battery cells and capable of cooling each battery cell, tightly pressing and fixing each battery cell.SOLUTION: A battery pack (1) includes a battery case (10), battery cells (20) and a coolant jacket (30). The coolant jacket (30) includes: two plastic thin plates (31 and 32) which are mutually surface-bonded; and a coolant inlet (33), a coolant passage (43) and a coolant outlet (35) as gap portions. The battery cell (20) and the coolant jacket (30) are arrayed alternately in surface contact inside of the battery case (10). A non-compressed fluid of a predetermined pressure is caused to flow into the coolant passage (34) of the coolant jacket (30) and the coolant jacket (30) is expanded by plastic deformation, such that the battery cell (20) and the coolant jacket (30) are held and fixed between two end plates (11 and 12).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a battery pack for a BEV (battery electric vehicle) and a manufacturing method thereof. [Background technology]

[0002] Battery cells used in battery packs for BEVs (battery electric vehicles) need to be mounted under pressure at a given load. For this reason, currently, most battery packs have a battery module formed by bundling and binding multiple cells together, and multiple such modules are mounted (see, for example, Patent Document 1). Also, the battery cells need temperature management to ensure their performance. Currently, to deal with heat generation during charging and discharging, a water jacket for cooling (and heating as necessary) is laid out under the module mounting section, and temperature management is performed from the bottom of the battery cells.

[0003] In such a module-to-pack (MTP) battery pack, the amount of battery cells that can be mounted is limited by the space used by the structure of each battery module. In order to meet the demand for larger battery capacity and higher voltage, a cell-to-pack (CTP) system in which battery cells are directly mounted on a battery pack is being considered (see, for example, Patent Documents 2 and 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-16467 A [Patent Document 2] Special table 2023-502274 publication [Patent Document 3] Special Publication No. 2023-509695 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the cell-to-pack method, it is very difficult to arrange the individual battery cells in the pack while applying pressure to the battery cells. In addition, when supporting rapid charging, temperature control of the battery becomes more important, but bottom cooling has its limits, and cooling of the side of the cells is required.

[0006] The present invention has been made to solve these problems, and aims to provide a battery pack that enables an increase in the mounting density of battery cells, and that enables cooling, compression, and fixing of each battery cell. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention provides a battery pack (1) including a substantially box-shaped battery case (10), a plurality of battery cells (20) housed in the battery case, and a plurality of refrigerant jackets (30) for cooling the plurality of battery cells, wherein each of the refrigerant jackets (30) includes two thin plates (31, 32) having plasticity and surface-joined to each other, and a refrigerant inlet (33), a refrigerant passage (34), and a refrigerant outlet (35) formed as gaps between the two thin plates, The cells (20) and the refrigerant jackets (30) are arranged in a first direction (AA) in alternating face-to-face contact within the battery case (10), and are formed by sandwiching and fixing the plurality of battery cells (20) and the plurality of refrigerant jackets (30) between two end plates (11, 12) facing each other in the first direction by flowing a non-compressible fluid at a predetermined pressure into the refrigerant passage (34) of each of the refrigerant jackets (30) to expand the refrigerant jackets (30) by plastic deformation.

[0008] With this configuration, the battery cells and the pre-expanded refrigerant jackets are alternately arranged with a gap between them and the two opposing end plates, and then the refrigerant jackets are expanded, thereby fixing the battery cells with pressure applied to them. In addition, because the refrigerant jacket expands due to plastic deformation, the deformed state is maintained even if the hydraulic pressure is reduced to zero, and the pressure on the battery cells is also maintained, eliminating the need for a separate pressure mechanism and simplifying the structure.

[0009] A configuration in which the two end plates (11, 12) are end plates that constitute both ends of the battery cell housing portion (17) in the battery case (17) can be preferably adopted.

[0010] This configuration, i.e., the configuration in which the present invention is applied to a cell-to-pack type battery pack in which battery cells are directly housed in a battery case without being modularized, has the following effect in addition to the above effects: When the battery cells are mounted in the case, because there is a gap between the battery cells and the inner wall of the battery case before the refrigerant jacket expands, various mounting methods can be selected, such as mounting the battery cells in a row or as a whole set by gripping them with a robot hand, or mounting them from above using a loader. In addition, since the refrigerant jacket expands to fill the space defined by the battery cells and the inner wall of the battery case, it is also possible to absorb dimensional variations that occur during manufacturing of the battery case and battery cells. Furthermore, by flowing a refrigerant (cooling water, etc.) through the refrigerant flow path between the two thin plates that make up the refrigerant jacket after expansion, it is possible to cool the side of the cell, making it possible to accommodate rapid charging, which generates a lot of heat. In addition, the refrigerant jacket is rigid despite being hollow and lightweight, which also contributes to improving the rigidity of the entire battery pack.

[0011] A configuration in which the battery cells (10) are arranged in a row in a second direction (BB) perpendicular to the first direction (AA) and joined to form a cell assembly (20A), and the cell assembly (20A) and the refrigerant jacket (30) are arranged in surface contact with each other alternately in the first direction (AA) within the battery case (1) can be preferably adopted.

[0012] This configuration allows the battery cells to be arranged two-dimensionally in the battery pack, enabling a high-density arrangement.

[0013] The refrigerant jacket (30) has one end (30a) protruding from one end side of the cell assembly (20A) in the second direction (BB) and another end (30b) protruding from the other end side of the cell assembly (20A), the refrigerant inlet (33) has one face side inlet piping (33a) protruding in the first direction (AA) from one face side of the one end (30a) and another face side inlet piping (33b) protruding in the first direction (AA) from the other face side of the one end (30a), and the refrigerant outlet (35) has one face side inlet piping (33a) protruding in the first direction (AA) from one face side of the other end (30b). a second surface outlet pipe (35a) protruding from the second surface side of the second end (30b) in the first direction (AA), and a third surface outlet pipe (35b) protruding from the second surface side of the second end (30b) in the first direction (AA). When two of the refrigerant jackets (30) are adjacent to each other with the cell assembly (20) in between, the first surface inlet pipe (33a) of one of the refrigerant jackets (30) is connected to the second surface inlet pipe (33b) of the other refrigerant jacket (30) and the first surface outlet pipe (35a) of one of the refrigerant jackets (30) is connected to the second surface outlet pipe (35b) of the other refrigerant jacket (30).

[0014] It is particularly preferable to adopt a configuration in which the connection between the one surface side inlet pipe (33a) and the other surface side inlet pipe (33b) and the connection between the one surface side outlet pipe (35a) and the other surface side outlet pipe (35b) are each made via a flexible hose (36).

[0015] With these configurations, the refrigerant inlets and refrigerant outlets of multiple refrigerant jackets can be easily connected to each other, and the refrigerant can be flowed through all of the refrigerant jackets by sealing the unconnected refrigerant inlets and refrigerant outlets of the terminal refrigerant jackets and then injecting refrigerant through the refrigerant inlet of the base-end refrigerant jacket.

[0016] The predetermined pressure is preferably 10 times or more the pressure of the refrigerant during normal use, and more preferably 3±0.5 MPa.

[0017] This configuration allows the coolant jacket to be appropriately expanded and the battery cells to be fixed in place while pressure is applied to the battery cells.

[0018] The battery cell (20) or the cell combination (20A) is preferably fixed to the adjacent refrigerant jacket (30) by adhesive.

[0019] With this configuration, it is possible to prevent the battery cells from becoming misaligned when the refrigerant jacket is expanded.

[0020] The manufacturing method of the battery pack (1) of the present invention is a method for manufacturing the battery pack (1) including a substantially box-shaped battery case (10), a plurality of battery cells (20) housed in the battery case (10), and a plurality of refrigerant jackets (30) for cooling the plurality of battery cells (20), wherein each of the refrigerant jackets (30) includes two thin plates (31, 32) having plasticity and surface-joined to each other, and a refrigerant inlet (33), a refrigerant passage (34), and a refrigerant outlet (35) formed as gaps between the two thin plates (31, 32). The method includes the steps of: arranging the battery cells (20) and the refrigerant jackets (30) in a first direction (AA) within the battery case (10) in such a manner that the battery cells (20) and the refrigerant jackets (30) are alternately in surface contact with each other within the battery case (10); and introducing a non-compressible fluid at a predetermined pressure into the refrigerant passages (34) of each of the refrigerant jackets (30) to expand the refrigerant jackets (30) by plastic deformation, thereby sandwiching and fixing the plurality of battery cells (20) and the plurality of refrigerant jackets (30) between two end plates (11, 12) facing each other in the first direction.

[0021] With this configuration, the battery cells and the unexpanded refrigerant jackets are alternately arranged with a gap between them and the two opposing end plates, and then the refrigerant jackets are expanded, thereby fixing the battery cells with pressure applied to them. The reference numerals in parentheses above are shown as an example of the present invention, and are the reference numerals of corresponding components in the embodiment described below. Effect of the Invention

[0022] According to the battery pack and manufacturing method thereof of the present invention, the battery cells and the unexpanded refrigerant jackets are alternately arranged with a gap between them and the two opposing end plates, and then the refrigerant jackets are expanded, thereby fixing the battery cells with pressure applied to them. In addition, because the refrigerant jacket expands due to plastic deformation, the deformed state is maintained even if the hydraulic pressure is reduced to zero, and the pressure on the battery cells is also maintained, eliminating the need for a separate pressure mechanism and simplifying the structure. [Brief description of the drawings]

[0023] [Figure 1] 1 is a plan view illustrating a battery pack according to a first embodiment of the present invention. [Diagram 2] An enlarged view of part A of the battery pack in Figure 1. [Diagram 3] FIG. 1 shows a cell assembly, where (a) is a plan view and (b) is a front view. [Figure 4] FIG. 2 shows a refrigerant jacket, where (a) is a plan view and (b) is a front view. [Diagram 5] 5 is a schematic diagram showing a cross section of the refrigerant jacket taken along line BB in FIG. 4, where (a) shows the state before expansion and (b) shows the state after expansion. [Figure 6] FIG. 2 is a plan view showing the manufacturing method of the battery pack in FIG. 1; (a) shows the battery cells before bonding, (b) shows the joined cells after bonding, (c) shows the cell joint and the adhesive body of the refrigerant jacket before expansion, and (d) shows the state after the flexible hose is attached. [Figure 7]FIG. 2 is a plan view illustrating a method for manufacturing the battery pack of FIG. 1, showing a state in which the cell assembly and the bonded assembly of the refrigerant jacket before expansion are arranged in a battery case. [Figure 8] FIG. 6 is a plan view showing a battery pack according to a second embodiment of the present invention. [Figure 9] An enlarged view of part E of the battery pack in Figure 8. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. First Embodiment In this embodiment, the refrigerant inlet pipe and the refrigerant outlet pipe of the refrigerant jacket are connected by a flexible hose. As shown in FIG. 1 and the enlarged view 2 of part C in FIG. 1, the battery pack 1 of this embodiment includes a battery case 10, a plurality of battery cells 20, and a plurality of refrigerant jackets 30.

[0025] The battery case 10 has a thin box shape composed of a front end plate 11 and a rear end plate 12 provided at both ends in a first direction (front-to-back direction AA), a left end plate 13 and a right end plate 14 provided at both ends in a second direction (left-to-right direction BB), a bottom plate 15, and a top plate (not shown).

[0026] As shown in FIG. 3, in this embodiment, the battery cell 20 is a rectangular lithium ion battery with two terminals 21 protruding from the upper side. Six battery cells 20 are arranged in a row in the second direction (left-right direction) and joined to form a cell assembly 20A. However, in the present invention, the shape of the battery cell 20 is not limited to a rectangular shape and may be, for example, a cylindrical shape. However, a rectangular shape has the advantage that resin is not required to fill the gaps between the battery cells 20, and the environmental load during recycling is small. Furthermore, the type of battery is not limited to a lithium ion battery and may be an all-solid-state lithium ion battery, a sodium ion battery, or the like.

[0027] The refrigerant jacket 30 is a component that is arranged in surface contact with the cell assembly 20A alternately in a first direction (front-rear direction) inside the battery case 10 and cools each battery cell 20. As shown in FIG. 4, each refrigerant jacket 30 is a roll-bonded component that includes two aluminum plastic thin plates 31, 32 (see FIG. 5) that are surface-bonded to each other, and a refrigerant inlet 33, a refrigerant passage 34, and a refrigerant outlet 35 formed as gaps between the two thin plates. By introducing a non-compressible fluid of a predetermined pressure (water at 3.4 MPa in this embodiment) into the refrigerant passage 34 of the refrigerant jacket 30 to expand the refrigerant passage 34, even a normal pressure refrigerant (water at 0.3 MPa) can flow through it. At the same time, the refrigerant jacket 30 expands due to plastic deformation, so that the cell assembly 20A and the refrigerant jacket 30 are sandwiched and fixed between the front end plate 11 and the rear end plate 12 (see FIG. 1) that form both end plates of the battery cell storage section 17.

[0028] The refrigerant jacket 30 has one end 30a protruding from one end (left side) of the cell assembly 20A in the second direction (left-right direction) and the other end 30b protruding from the other end (right side) of the cell assembly 20A. The refrigerant inlet 33 has one surface inlet piping 33a protruding in a first direction (front-rear direction) from one surface side (front side) of the one end 30a, and another surface inlet piping 33b protruding in the first direction (front-rear direction) from the other surface side (rear side) of the one end 30a. On the other hand, the refrigerant outlet 35 has a one-side outlet piping 35a protruding in a first direction (front-to-back direction) from one side (front side) of the other end 30b, and an other-side outlet piping 35b protruding in the first direction (front-to-back direction) from the other side (rear side) of the other end 30b.

[0029] As shown in FIG. 2, of two refrigerant jackets 30 adjacent to each other with the cell assembly 20A in between, one of the refrigerant jackets 30 has a first inlet pipe 33a connected to a second inlet pipe 33b of the other refrigerant jacket 30 via an aluminum flexible hose 36. Also, one outlet pipe 35a of the first refrigerant jacket 30 is connected to a second outlet pipe 35b of the other refrigerant jacket 30 via a flexible hose 36. In this manner, the refrigerant inlets 33 of all the refrigerant jackets 30 arranged in the battery case 10 are connected to each other, and the refrigerant outlets 35 are connected to each other, and the first inlet pipe 33a and the first outlet pipe 35a of the first refrigerant jacket 30 are not provided, and the first side is sealed. On the other hand, the second inlet pipe 33b of the last refrigerant jacket 30 is connected to a refrigerant supply pipe 37 (see FIG. 1), and the first outlet pipe 35a is connected to a refrigerant return pipe 38 (see FIG. 1). When refrigerant (water) is supplied from the refrigerant supply pipe 37 to a group of refrigerant jackets 30 connected in this manner, the water branches out and flows in parallel through the refrigerant passages 34 of each refrigerant jacket 30 to cool the battery cells 20, and then joins together and flows into the refrigerant return pipe 38.

[0030] Two terminals 21 (see FIG. 3) protruding from the upper side of each battery cell 20 are connected by welding to a bus bar (not shown), which is a conductive plate, and are connected in parallel and in series within the battery pack, and are finally integrated into a positive terminal (not shown) and a negative terminal (not shown) for the entire battery pack. By applying a voltage between the positive terminal and the negative terminal from the outside, it is possible to charge each battery cell 20, and the power charged in each battery cell 20 can be supplied from the positive terminal and the negative terminal to a vehicle drive motor, etc.

[0031] Next, a method for manufacturing the battery pack 1 of this embodiment configured as described above will be described. First, as shown in Figures 6(a) and (b), a plurality of battery cells 20 (six in this embodiment) are arranged in a row in the second direction (left-right direction) and joined to form a cell assembly 20A (Figure 5(a)).

[0032] Next, the cell assemblies 20A and the refrigerant jackets 30 are alternately arranged in a first direction (front-rear direction) so as to be in surface contact with each other, and are bonded to each other. Specifically, first, one refrigerant jacket 30 is bonded to one cell assembly 20A so as to be in surface contact with each other (FIG. 6(c)), and aluminum flexible hoses 36 are attached to one side inlet pipe 33a and one side outlet pipe 35a provided at the left and right ends of the refrigerant jacket 30, respectively (FIG. 6(d)). Next, the cell assembly 20A and the bonded assembly of the refrigerant jacket 30 are aligned and bonded one after the other inside the battery case 10 as shown in Fig. 7. By bonding them, it is possible to prevent the alignment of the battery cells 20 from shifting during the process of expanding the refrigerant jacket 30, which will be described later. 2, of the two refrigerant jackets 30 adjacent to each other with the cell assembly 20A in between, the other side inlet pipe 33b and the other side outlet pipe 35b of one refrigerant jacket 30 are fitted into the flexible hoses 36 attached to the one side inlet pipe 33a and the one side outlet pipe 35a of the other refrigerant jacket 30, respectively, to connect the inlet pipes (33a, 33b) to each other and the outlet pipes (35a, 35b) to each other. Note that the one side inlet pipe 33a and the one side outlet pipe 35a of the front-most refrigerant jacket 30 are not provided, and the one side is sealed. When all of the cell assemblies 20A and the adhesive bodies of the refrigerant jackets 30 are arranged and bonded, the refrigerant inlets 33 of all of the refrigerant jackets 30 arranged inside the battery case 10 are connected to each other, and the refrigerant outlets 35 are connected to each other.

[0033] 7, which is a block in which the cell assemblies 20A and the refrigerant jackets 30 are alternately arranged, the thickness of the refrigerant jackets 30 has not yet expanded, so the dimension of the cell body 40 in the first direction (front-rear direction) is sufficiently smaller than the dimension of the battery cell housing section 17 in the battery case 10. Therefore, in the first direction, there is a space S between the cell body 40 and the rear end plate 12 or the front end plate 11, and various methods for transporting the bonded assembly of the cell assemblies 20A and the refrigerant jackets 30 can be used.

[0034] Next, after sealing the one-side outlet pipe 35a of the last-stage refrigerant jacket 30, the refrigerant supply pipe 37 is connected to the other-side inlet pipe 33b, and a non-compressible fluid of a predetermined pressure (water at 3.4 MPa in this embodiment) is made to flow into the refrigerant passage 34 (see FIG. 4) of the refrigerant jacket 30. This non-compressible fluid may be the same as or different from the refrigerant. As a result, the refrigerant jacket 30 expands due to plastic deformation, so that even if the refrigerant pressure is reduced to zero, the deformed state is maintained, and even a refrigerant of normal pressure (water at 0.3 MPa) can flow through the expanded refrigerant passage 34. At the same time, the pressure on the battery cell 20 is maintained, so the cell assembly 20A and the refrigerant jacket 30 are sandwiched and fixed between the rear end plate 12 and the front end plate 11 that form the two end plates of the battery cell housing portion 17, and the terminals 21 of the battery cells 20 are correctly positioned (FIG. 1).

[0035] A bus bar (not shown), which is a conductive plate, is placed on the surface of each battery cell 20 on which terminals 21 are arranged (the upper surface in FIG. 1), and is welded to each terminal 21.

[0036] Furthermore, a refrigerant supply pipe 37, a refrigerant return pipe 38, etc. are connected, urethane foam is filled in the gap around the cell body 40, and an upper plate (not shown) is adhered, thereby completing the battery pack 1.

[0037] According to this embodiment, the battery cells 20 and the refrigerant jackets 30 before expansion are alternately arranged with a gap between them and the two opposing end plates (11, 12), and then the refrigerant jackets 30 are expanded, thereby fixing the battery cells 20 with pressure applied to them. In addition, since the refrigerant jacket 30 expands due to plastic deformation, the deformed state is maintained even if the hydraulic pressure is reduced to zero, and the pressure on the battery cells 20 is also maintained, eliminating the need for a separate pressure mechanism and simplifying the structure.

[0038] Second Embodiment In this embodiment, the refrigerant jackets 30 in the first embodiment are connected to each other by straight steel pipes (33a, 33b, 35a, 35b) instead of the flexible hose 36. The same or substantially the same components as those in the first embodiment are denoted by the same reference numerals, and duplicated explanations will be omitted. Fig. 8 shows a plan view of the battery pack according to this embodiment, and Fig. 9 shows an enlarged view of part E.

[0039] The refrigerant jacket 30 has one end 30a protruding from one end (left side) of the cell assembly 20A in the second direction (left-right direction) and the other end 30b protruding from the other end (right side) of the cell assembly 20A. The refrigerant inlet 33 has one face inlet piping 33a protruding in a first direction (front direction) from one face side (front side) of the one end 30a, and another face inlet piping 33b protruding in the first direction (rear direction) from the other face side (rear side) of the one end 30a. The outer periphery of the other face inlet piping 33b is formed to a size that allows it to be press-fitted into the inner periphery of the one face inlet piping 33a. On the other hand, the refrigerant outlet 35 has one surface side outlet piping 35a protruding in a first direction (front direction) from one surface side (front side) of the other end 30b, and another surface side outlet piping 35b protruding in the first direction (rear direction) from the other surface side (rear side) of the other end 30b. The outer periphery of the other surface side outlet piping 35b is also formed to a size that allows it to be press-fitted into the inner periphery of the one surface side outlet piping 35a.

[0040] When the two refrigerant jackets 30 are press-fitted with the one-side inlet pipe 33a of one of the refrigerant jackets 30, the other-side inlet pipe 33b of the other refrigerant jacket 30 is press-fitted and connected to the one-side outlet pipe 35a of the one refrigerant jacket 30. In this way, the refrigerant inlets 33 of all the refrigerant jackets 30 arranged in the battery case 10 are connected to each other, and the refrigerant outlets 35 are connected to each other, and the one-side inlet pipe 33a and the one-side outlet pipe 35a of the refrigerant jacket 30 at the front stage are not provided, and the one side is sealed. On the other hand, the refrigerant supply pipe 37 is connected to the other-side inlet pipe 33b of the refrigerant jacket 30 at the last stage, and the refrigerant return pipe 38 is connected to the one-side outlet pipe 35a.

[0041] A refrigerant supply pipe 37 is connected to the other side inlet pipe 33b of the group of refrigerant jackets 30 connected in this manner, and a non-compressible fluid of a predetermined pressure (water at 3.4 MPa in this embodiment) is made to flow into the refrigerant passage 34 (see FIG. 4) of the refrigerant jacket 30. As a result, as in the first embodiment, the refrigerant jacket 30 expands due to plastic deformation, and even a refrigerant of normal pressure (water at 0.3 MPa) can flow through the expanded refrigerant passage 34. At the same time, the cell assembly 20A and the refrigerant jacket 30 are sandwiched and fixed between the rear end plate 12 and the front end plate 11 that form the two end plates of the battery cell housing portion 17, and the terminals 21 of the battery cells 20 are correctly positioned (FIG. 1). At this time, due to the expansion of each refrigerant jacket 30, tension is applied to the fitting portion between the one-side inlet piping 33a and the other-side inlet piping 33b and the fitting portion between the one-side outlet piping 35a and the other-side outlet piping 35b. However, the thickness of the one end 20a and the other end 30b of the refrigerant jacket 30 also expands, so the fitting is maintained.

[0042] The rest of the configuration is the same as in the first embodiment, and the manufacturing method is also the same as in the first embodiment except that the assembly process does not use the flexible hose 36. Since there is no need to attach the flexible hose 36 (see FIG. 2) to the one-side inlet piping 33a and the one-side outlet piping 35a in the assembly process, the assembly process can be simplified.

[0043] Although an embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible within the scope of the claims and the technical ideas described in the specification and drawings. For example, in each of the above embodiments, an example is described in which the battery cells 20 are directly accommodated in the battery case 10 without being modularized, but the present invention is not limited to this and can also be applied to a module-to-pack battery pack 1. In this case, the battery cells 20 and the refrigerant jackets 30 are arranged in a first direction in a frame of a module in a surface contact with each other, and a non-compressible fluid of a predetermined pressure is introduced into the refrigerant passage 34 of each refrigerant jacket 30 to expand the refrigerant jacket 30 by plastic deformation, thereby sandwiching and fixing the multiple battery cells 20 and the multiple refrigerant jackets 30 between two end plates facing each other in the first direction to form a module, which may be arranged in a multiple battery pack 1.

[0044] Furthermore, the piping connection structures on the inlet and outlet sides of the refrigerant jacket 30 are not limited to those in the above-described embodiments, and any structure that allows the refrigerant to flow through the refrigerant jacket 30 may be used. [Explanation of symbols]

[0045] 1 Battery pack 10 Battery case 11 Front end plate 12 Rear end plate 13 Left end plate 14 Right end plate 15 Bottom plate 17 Battery cell housing 20 Battery Cells 20A Cell Joint 21 Terminal 30 Refrigerant jacket 30a One end 30b Other end 31,32 thin plate 33 Refrigerant inlet 33a One side inlet piping 33b Other side inlet piping 34 Refrigerant passage 35 Refrigerant outlet 35a One side outlet piping 35b Other side outlet piping 36 Flexible Hose 37 Refrigerant supply piping 38 Refrigerant return pipe 40 Cell Body S Space

Claims

1. A roughly box-shaped battery case; A plurality of battery cells housed in the battery case; a plurality of refrigerant jackets for cooling the plurality of battery cells, Each of the refrigerant jackets includes two plastic thin plates that are surface-bonded to each other, and a refrigerant inlet, a refrigerant passage, and a refrigerant outlet that are formed as gaps between the two thin plates, The battery cells and the refrigerant jackets are arranged in a first direction in the battery case in alternating surface contact with each other, a battery pack formed by sandwiching and fixing the plurality of battery cells and the plurality of refrigerant jackets between two end plates facing each other in the first direction, the battery pack being formed by injecting a non-compressible fluid at a predetermined pressure into the refrigerant passage of each of the refrigerant jackets to expand the refrigerant jackets through plastic deformation.

2. The battery pack according to claim 1 , wherein the two end plates are end plates that constitute both ends of a battery cell housing portion in the battery case.

3. The plurality of battery cells are arranged in a row in a second direction perpendicular to the first direction to form a cell assembly, The battery pack according to claim 2 , wherein the cell assemblies and the coolant jackets are arranged in surface contact with each other alternately in the first direction inside the battery case.

4. the refrigerant jacket has one end protruding from one end side of the cell assembly in the second direction and another end protruding from the other end side of the cell assembly, the refrigerant inlet includes a first surface side inlet pipe protruding in the first direction from one surface side of the one end portion, and an other surface side inlet pipe protruding in the first direction from the other surface side of the one end portion, the refrigerant outlet includes a one-surface-side outlet pipe protruding in the first direction from one surface side of the other end portion, and an other-surface-side outlet pipe protruding in the first direction from the other surface side of the other end portion, When the two refrigerant jackets are adjacent to each other with the cell assembly interposed therebetween, the one-side inlet pipe of one of the refrigerant jackets is connected to the other-side inlet pipe of the other refrigerant jacket, The battery pack according to claim 3 , wherein the one-side outlet pipe of one of the refrigerant jackets is configured to be connected to the other-side outlet pipe of another of the refrigerant jackets.

5. 5. The battery pack according to claim 4, wherein the connection between the one surface side inlet pipe and the other surface side inlet pipe and the connection between the one surface side outlet pipe and the other surface side outlet pipe are each made via a flexible hose.

6. 5. The battery pack according to claim 4, wherein the predetermined pressure is 10 times or more the pressure of the refrigerant during normal use.

7. 7. The battery pack according to claim 6, wherein the predetermined pressure is 3±0.5 MPa.

8. The battery pack according to claim 1 , wherein the battery cells or the cell combinations are fixed to the adjacent coolant jackets by adhesive.

9. A roughly box-shaped battery case; A plurality of battery cells housed in the battery case; a plurality of refrigerant jackets for cooling the plurality of battery cells; A method of manufacturing a battery pack comprising: Each of the refrigerant jackets includes two thin plates having plasticity and surface-bonded to each other, and a refrigerant inlet, a refrigerant passage, and a refrigerant outlet formed as gaps between the two thin plates, arranging the battery cells and the refrigerant jackets in a first direction in the battery case so as to be in surface contact with each other in the battery case; and a step of injecting a non-compressible fluid at a predetermined pressure into the refrigerant passage of each of the refrigerant jackets to expand the refrigerant jackets by plastic deformation, thereby sandwiching and fixing the plurality of battery cells and the plurality of refrigerant jackets between two end plates facing each other in the first direction.

Images