Battery module

Abstract

To provide a battery module which can suppress increase of manufacturing steps and cost and can suppress thermal expansions.SOLUTION: A battery module 11 includes: a long battery cell 20 formed by sealing an electrode body with a laminate film; and a case 13 for storing a battery cell group in which a plurality of battery cells 20 are arranged. The case 13 includes: a pair of shorter-side wall parts 13A extending along the direction of lamination of the battery cells 20; and a pair of longer-side wall parts 13B connecting the shorter-side wall parts 13A to each other. The longer-side wall parts 13B are formed not to be easily deformed in the thickness direction with respect to the shorter-side wall parts 13A.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a battery module. [Background Art]

[0002] Patent Document 1 discloses a battery module in which an electrode assembly is housed in a case. Further, the outer side of the electrode assembly is surrounded by a heat-shrinkable protective layer, so that the structure suppresses thermal expansion of the electrode assembly. [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2018 / 287184 [Summary of the Invention] [Problems to be Solved by the Invention]

[0004] However, since the heat-shrinkable protective layer is formed, manufacturing man-hours and costs increase compared to a structure where the heat-shrinkable protective layer is not formed.

[0005] In view of the above facts, an object of the present invention is to obtain a battery module that can suppress thermal expansion while suppressing increases in manufacturing man-hours and costs. [Means for Solving the Problems]

[0006] A battery module according to claim 1 comprises: an elongated battery cell formed by sealing an electrode body with a laminate film; and a case capable of housing a battery cell group in which a plurality of said battery cells are arranged, wherein said case is configured to include a pair of short side wall portions extending along the stacking direction of said battery cells, and a pair of long side wall portions connecting said short side wall portions to each other, The aforementioned long side wall portion is formed with a greater thickness in the central part in the longitudinal direction than in other parts. .

[0007] In the battery module according to claim 1, the battery cells are formed by sealing electrode bodies with a laminate film and are elongated in shape. The case is capable of housing a group of battery cells arranged in a plurality of configurations. The case is composed of a pair of short side walls extending along the stacking direction of the battery cells and a pair of long side walls connecting the short side walls, with the long side walls being shaped to be less deformable in the thickness direction relative to the short side walls. As a result, when the battery cells undergo thermal expansion, a reaction force is applied from the long side walls of the case to the battery cells, thereby suppressing the thermal expansion of the battery cells. Furthermore, because the long side walls of the case are shaped to be less deformable in the thickness direction to suppress the thermal expansion of the battery cells, there is no need for a special component such as a heat-shrinkable protective layer.

[0013] Also Because the central part of the long side wall is thicker in the longitudinal direction, it has higher strength than other parts. This allows it to effectively receive the force from the battery cell when the battery cell expands due to heat, while also reducing weight compared to when the entire long side wall is thickened.

[0014] Claim 2 The battery module relating to this is The battery comprises a long battery cell formed by sealing an electrode body with a laminate film, and a case capable of housing a group of battery cells arranged in a plurality of the battery cells, wherein the case is composed of a pair of short side walls extending along the stacking direction of the battery cells and a pair of long side walls connecting the short side walls. The connection portion between the long side wall and the short side wall is formed to be thicker than other parts.

[0015] Claim 2 In the battery module, even if a load is applied from the battery cell to the long side wall during thermal expansion and the load concentrates at the connection point between the long side wall and the short side wall, deformation can be suppressed because this connection point is thicker than other parts. [Effects of the Invention]

[0016] As described above, the battery module according to the present invention can suppress thermal expansion while suppressing increases in manufacturing man-hours and costs. [Brief explanation of the drawing]

[0017] [Figure 1] This is a schematic plan view showing the main parts of a vehicle to which the battery pack according to the first embodiment is applied. [Figure 2] This is a schematic perspective view of the battery module according to the first embodiment. [Figure 3] This is a schematic diagram of a battery cell housed in a battery module according to the first embodiment, viewed from the thickness direction. [Figure 4] This is a plan view of the battery module according to the first embodiment with the top cover removed. [Figure 5] This is a plan view of the battery module according to the second embodiment with the top cover removed. [Figure 6] This is a plan view of the battery module according to the third embodiment with the top cover removed. [Modes for carrying out the invention]

[0018] <First Embodiment> The battery module 11 according to the first embodiment will be described with reference to the drawings.

[0019] (Overall configuration of vehicle 100) Figure 1 is a schematic plan view showing the main parts of a vehicle 100 to which the battery module 11 according to this embodiment is applied. As shown in Figure 1, the vehicle 100 is a battery electric vehicle (BEV) with a battery pack 10 mounted under the floor. In each figure, the arrows UP, FR, and LH indicate the upper side in the vertical direction of the vehicle, the front side in the longitudinal direction of the vehicle, and the left side in the width direction of the vehicle, respectively. When describing the directions of front, rear, left, right, up, and down, unless otherwise specified, they refer to the front and rear in the longitudinal direction of the vehicle, the left and right in the width direction of the vehicle, and the up and down in the vertical direction of the vehicle.

[0020] As an example, in the vehicle 100 of the present embodiment, a DC / DC converter 102, an electric compressor 104, and a PTC (Positive Temperature Coefficient) heater 106 are arranged on the vehicle front side relative to the battery pack 10. Further, a motor 108, a gear box 110, an inverter 112, and a charger 114 are arranged on the vehicle rear side relative to the battery pack 10.

[0021] The direct current output from the battery pack 10 has its voltage adjusted by the DC / DC converter 102, and is then supplied to the electric compressor 104, the PTC heater 106, the inverter 112 and the like. Further, electric power is supplied to the motor 108 via the inverter 112, whereby the rear wheels rotate to cause the vehicle 100 to travel.

[0022] A charging port 116 is provided on the right side of the rear portion of the vehicle 100, and when a charging plug of an external charging facility (not shown) is connected via the charging port 116, electric power can be stored in the battery pack 10 via the on-board charger 114.

[0023] It should be noted that the arrangement and structure of each component constituting the vehicle 100 are not limited to the configuration described above. For example, the present invention may be applied to a hybrid vehicle (HV: Hybrid Vehicle) equipped with an engine or a plug-in hybrid electric vehicle (PHEV: Plug-in Hybrid Electric Vehicle). Further, although the present embodiment adopts a rear-wheel drive vehicle in which the motor 108 is mounted on the rear portion of the vehicle, the present invention is not limited thereto, and may be a front-wheel drive vehicle in which the motor 108 is mounted on the front portion of the vehicle, or a pair of motors 108 may be mounted on the front and rear of the vehicle. Furthermore, the vehicle may be provided with an in-wheel motor for each wheel.

[0024] Here, the battery pack 10 is composed of multiple battery modules 11. In this embodiment, as an example, 10 battery modules 11 are provided. Specifically, 5 battery modules 11 are arranged in the longitudinal direction of the vehicle on the right side of the vehicle 100, and 5 battery modules 11 are arranged in the longitudinal direction of the vehicle on the left side of the vehicle 100. Furthermore, each battery module 11 is electrically connected.

[0025] Figure 2 is a schematic perspective view of the battery module 11. As shown in Figure 2, the battery module 11 is formed in a roughly rectangular parallelepiped shape with the vehicle width direction as the longitudinal direction. The case 13 of the battery module 11 is made of aluminum alloy. For example, the case 13 of the battery module 11 is formed by joining aluminum die-cast parts to both ends of an aluminum alloy extruded material by laser welding or the like.

[0026] A pair of voltage terminals 12 and a connector 14 are provided at both ends of the battery module 11 in the vehicle width direction. A flexible printed circuit board 21, which will be described later, is connected to the connector 14. In addition, busbars (not shown) are welded to both ends of the battery module 11 in the vehicle width direction.

[0027] The length MW of the battery module 11 in the vehicle width direction is, for example, 350 mm to 600 mm, the length ML in the vehicle longitudinal direction is, for example, 150 mm to 250 mm, and the height MH in the vehicle vertical direction is, for example, 80 mm to 110 mm.

[0028] Figure 3 is a schematic view of a battery cell 20 housed in a battery module 11, viewed from the thickness direction. As shown in Figure 3, the battery cell 20 is formed in a roughly rectangular plate shape, and a long electrode body 19 is housed inside. The electrode body 19 is constructed by laminating a positive electrode, a negative electrode, and a separator, and is sealed with a laminate film 22.

[0029] In this embodiment, as an example, the housing portion for the electrode body 19 is formed by folding and bonding an embossed sheet-like laminate film 22. While both a single-cup embossed structure with one embossed area and a double-cup embossed structure with two embossed areas can be employed, this embodiment uses a single-cup embossed structure with a fold depth of approximately 8mm to 10mm.

[0030] The upper ends of both longitudinal ends of the battery cell 20 are bent, and the corners form the outer shape. In addition, the upper end of the battery cell 20 is bent, and a fixing tape 24 is wrapped around the upper end of the battery cell 20 along the longitudinal direction.

[0031] Here, terminals (tabs) 26 are provided at both longitudinal ends of the battery cell 20. In this embodiment, as an example, the terminals 26 are provided at a position offset below the vertical center of the battery cell 20. The terminals 26 are joined to a busbar (not shown) by laser welding or the like.

[0032] The length CW1 of the battery cell 20 in the vehicle width direction is, for example, 530 mm to 600 mm, the length CW2 of the area housing the electrode body 19 is, for example, 500 mm to 520 mm, and the height CH of the battery cell 20 is, for example, 80 mm to 110 mm. For this reason, the battery cell 20 is formed in an elongated shape, and the directions of lengths CW1 and CW2 are the longitudinal directions.

[0033] Furthermore, the thickness of the battery cell 20 is 7.0mm to 9.0mm, and the height TH of the terminal 26 is 40mm to 50mm.

[0034] Figure 4 is a plan view of the battery module 11 according to the first embodiment with the top cover removed. As shown in Figure 4, the battery module 11 houses a group of battery cells, each containing multiple battery cells 20 arranged in a row. In this embodiment, as an example, 24 battery cells 20 are arranged in the front-rear direction of the vehicle and bonded to each other.

[0035] A flexible printed circuit board (FPC) 21 is placed on top of the battery cell 20. The flexible printed circuit board 21 is formed in a strip shape with the vehicle width direction as its longitudinal direction, and thermistors 23 are provided at both ends of the flexible printed circuit board 21. The thermistors 23 are not bonded to the battery cell 20, but are pressed toward the battery cell 20 by the upper cover of the battery module 11.

[0036] Furthermore, one or more buffer plates (not shown) are housed inside the battery module 11. For example, the buffer plates are elastically deformable thin plate-like members and are arranged between adjacent battery cells 20 with the arrangement direction of the battery cells 20 being the thickness direction. In this embodiment, as an example, buffer material is placed at both ends in the longitudinal direction and in the longitudinal center of the battery module 11, but buffer material may not be placed.

[0037] Here, the case 13 is composed of a pair of short side wall portions 13A extending along the stacking direction of the battery cells 20, and a pair of long side wall portions 13B connecting the short side wall portions 13A, and the long side wall portions 13B are formed in a shape that is less prone to deformation in the thickness direction compared to the short side wall portions 13A.

[0038] Specifically, the pair of short side wall portions 13A constituting case 13 are each formed in a substantially straight line when viewed from above. On the other hand, the pair of long side wall portions 13B are each formed in a shape where the central part in the longitudinal direction is convex inward. That is, the pair of long side wall portions 13B are each concave in opposite directions.

[0039] Furthermore, in this embodiment, the longitudinal central portion of the long side wall portion 13B is in contact with the battery cell 20 (battery cell group) when unloaded, and the battery cell group is restrained from both sides by the long side wall portion 13B.

[0040] (action) Next, the operation of the battery module 11 according to this embodiment will be explained.

[0041] In the battery module 11 according to this embodiment, the battery cell 20 is formed by sealing the electrode body 19 with a laminate film 22 and is elongated in shape. The case 13 is capable of housing a group of battery cells in which multiple battery cells 20 are arranged. Here, the long side wall portion 13B of the case 13 is formed in a shape that is less likely to deform in the thickness direction compared to the short side wall portion 13A. As a result, when the battery cell 20 undergoes thermal expansion, a reaction force is applied from the long side wall portion 13B of the case 13 to the battery cell 20, thereby suppressing the thermal expansion of the battery cell 20. Furthermore, because the long side wall portion 13B of the case 13 is shaped to be less likely to deform in the thickness direction, thereby suppressing the thermal expansion of the battery cell 20, there is no need for a special component such as a heat-shrinkable protective layer. In other words, the battery module 11 of this embodiment can suppress thermal expansion while suppressing increases in manufacturing man-hours and costs.

[0042] Furthermore, in this embodiment, the longitudinal central portion of the long side wall portion 13B is convex inward. Here, since the longitudinal central portion of the battery cell 20 tends to expand when it undergoes thermal expansion, the longitudinal central portion of the long side wall portion 13B is brought into contact with the battery cell group, thereby effectively suppressing the thermal expansion of the battery cell 20.

[0043] In particular, in this embodiment, since the long side wall portion 13B is in contact with the battery cell 20 (battery cell group) in the unloaded state, the long side wall portion 13B can apply restraining pressure to the battery cell group.

[0044] <Second Embodiment> Next, the battery module 50 according to the second embodiment will be described with reference to Figure 5. Note that components similar to those in the first embodiment are denoted by the same reference numerals, and their descriptions will be omitted as appropriate.

[0045] Figure 5 is a plan view of the battery module 50 in this embodiment with the top cover removed. As shown in Figure 5, in this embodiment, the long side wall portion 13B is formed with a greater thickness in the central part in the longitudinal direction than in other parts.

[0046] Specifically, the case 13 of the battery module 50 in this embodiment is composed of a pair of short side wall portions 13A formed in a substantially straight line in a plan view, and a pair of long side wall portions 13B formed in a substantially straight line in a plan view.

[0047] Here, each of the long side wall portions 13B has a thickened portion 52 formed in the longitudinal center. The thickened portion 52 is formed to be thicker than the other parts. As a result, the long side wall portion 13B is formed in a shape where the longitudinal center is convex inward. In addition, the thickened portion 52 is in contact with the battery cell 20 when there is no load.

[0048] (action) Next, the operation of the battery module 50 according to this embodiment will be explained.

[0049] In this embodiment, the thickened portion 52 in the longitudinal center of the long side wall portion 13B is thicker, resulting in higher strength than other parts. This allows the structure to effectively receive the force from the battery cell 20 during thermal expansion, while reducing weight compared to when the entire long side wall portion 13B is thickened. Other functions are the same as in the first embodiment.

[0050] <Third Embodiment> Next, the battery module 60 according to the third embodiment will be described with reference to Figure 6. Note that components similar to those in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted as appropriate.

[0051] Figure 6 is a plan view of the battery module 60 in this embodiment with the top cover removed. As shown in Figure 6, in this embodiment, the connection portion of the long side wall portion 13B with the short side wall portion 13A is formed to be thicker than other parts.

[0052] Specifically, the case 13 of the battery module 60 in this embodiment is composed of a pair of short side wall portions 13A formed in a substantially straight line in plan view, and a pair of long side wall portions 13B connecting the short side wall portions 13A.

[0053] Here, the long side wall portion 13B has an outer surface that is recessed toward the stacking direction of the battery cells 20. Also, the inner surface of the long side wall portion 13B is approximately parallel to the battery cells 20. For this reason, the long side wall portion 13B is formed in a shape in which the thickness increases from the center in the longitudinal direction toward the ends, and the connection portion of the long side wall portion 13B with the short side wall portion 13A is formed to be the thickest.

[0054] (action) Next, the operation of the battery module 60 according to this embodiment will be explained.

[0055] In this embodiment, even when a load is applied from the battery cell 20 to the long side wall portion 13B during thermal expansion of the battery cell 20, and the load is concentrated at the connection point between the long side wall portion 13B and the short side wall portion 13A, deformation can be suppressed because this connection point between the long side wall portion 13B and the short side wall portion 13A is thicker than other parts. Other functions are the same as in the first embodiment.

[0056] Although the battery modules 11, 50, and 60 according to the embodiment have been described above, the invention is not limited thereto and can be implemented in various forms without departing from the spirit of the present invention. For example, in the above embodiment, the longitudinal central portion of the long side wall portion 13B is in contact with the battery cell 20 in an unloaded state, but the invention is not limited thereto, and the long side wall portion may be configured not to be in contact with the battery cell.

[0057] Furthermore, in the first embodiment described above, the longitudinal center of the long side wall portion 13B was formed in a shape that is convex inward, but the embodiment is not limited to this and may be formed in other shapes. For example, the portion of the long side wall portion that is offset toward the end from the longitudinal center may be formed in a shape that is convex inward.

[0058] The following additional information is disclosed regarding the above embodiment.

[0059] (Note 1) A long battery cell formed by sealing the electrode body with a laminate film, A case capable of housing a group of battery cells arranged in multiples of the aforementioned battery cells, It has, The case is configured to include a pair of short side walls extending along the stacking direction of the battery cells, and a pair of long side walls connecting the short side walls. The long side wall portion is formed in a shape that is less prone to deformation in the thickness direction compared to the short side wall portion. Battery module. (Note 2) The aforementioned short side wall portion is formed in a straight line, The battery module as described in Appendix 1, wherein the long side wall portion is formed in a shape in which the central portion in the longitudinal direction is convex inward. (Note 3) The battery module according to Appendix 1 or 2, wherein the longitudinal central portion of the long side wall is in contact with the battery cell group in an unloaded state. (Note 4) The battery module according to any one of the appendices 1 to 3, wherein the long side wall portion is formed with a greater thickness in the central part in the longitudinal direction than in other parts. (Note 5) The battery module as described in Appendix 1, wherein the connection portion between the long side wall and the short side wall is formed to be thicker than other parts. [Explanation of Symbols]

[0060] 11 Battery Modules 13 cases 13A Short side wall section 13B Long side wall section 19 Electrode body 20 battery cells 22 Laminating film 50 Battery Modules 60 Battery Modules

Claims

1. A long battery cell formed by sealing the electrode body with a laminate film, A case capable of housing a group of battery cells arranged in multiples of the aforementioned battery cells, It has, The case is configured to include a pair of short side walls extending along the stacking direction of the battery cells, and a pair of long side walls connecting the short side walls. The aforementioned long side wall portion is formed with a greater thickness in the central part in the longitudinal direction than in other parts. Battery module.

2. A long battery cell formed by sealing an electrode body with a laminate film, A case capable of housing a group of battery cells arranged in multiples of the aforementioned battery cells, It has, The case is configured to include a pair of short side walls extending along the stacking direction of the battery cells, and a pair of long side walls connecting the short side walls. The connection portion between the long side wall and the short side wall is formed to be thicker than other parts. Battery module.

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