Battery module

Abstract

The battery module has: a long battery cell formed by encapsulating an electrode body with a laminated film; and a case capable of accommodating a battery cell group in which a plurality of battery cells are arranged, the case being configured so as to include a pair of short side wall sections extending in the stacking direction of the battery cells, and a pair of long side wall sections connecting the short side wall sections to each other. The long side wall portion is formed in a shape that is less likely to deform in the plate thickness direction than the short side wall portion.

Description

Technical Field

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

[0002] A battery module in which an electrode assembly is housed in a housing is disclosed in U.S. Patent Application Publication No. 2018 / 287184. In addition, the battery module has a structure in which the thermal expansion of the electrode assembly is suppressed by surrounding the outside of the electrode assembly with a heat-shrinkable protective layer. Summary of the invention

[0003] However, since the heat-shrinkable protective layer is formed, the manufacturing man-hours and costs increase compared to a structure in which the heat-shrinkable protective layer is not formed.

[0004] The present invention has been made in consideration of the above-mentioned facts, and an object of the present invention is to obtain a battery module capable of suppressing thermal expansion while suppressing increases in manufacturing man-hours and costs.

[0005] The battery module involved in Scheme 1 comprises: an elongated (long) battery cell formed by encapsulating an electrode body using a laminate film; and a shell capable of accommodating a battery cell group formed by arranging a plurality of the battery cells, the shell being constructed to include a pair of short side wall portions extending along the stacking direction of the battery cells, and a pair of long side wall portions connecting the short side wall portions to each other, the long side wall portions being formed to have a shape that is difficult to deform in the plate thickness direction relative to the short side wall portions.

[0006] In the battery module involved in Scheme 1, the battery cell is formed by encapsulating the electrode body with a laminate film to form an elongated shape. In addition, the shell can accommodate a battery cell group formed by arranging a plurality of battery cells. Here, the shell is configured to include a pair of short side wall portions extending along the stacking direction of the battery cells, and a pair of long side wall portions connecting the short side wall portions to each other, and the long side wall portions are formed into a shape that is difficult to deform in the plate thickness direction relative to the short side wall portions. Thus, when the battery cell undergoes thermal expansion, a reaction force is applied to the battery cell from the long side wall portions of the shell, thereby suppressing the thermal expansion of the battery cell. In addition, since the long side wall portions of the shell are formed into a shape that is difficult to deform in the plate thickness direction to suppress the thermal expansion of the battery cell, a dedicated component such as a heat shrinkable protective layer may not be required.

[0007] The battery module according to claim 2 is based on claim 1, wherein the short side wall portion is formed in a straight line shape, and the long side wall portion is formed in a shape in which the center portion in the longitudinal direction is convex inward.

[0008] In the battery module according to Scheme 2, the longitudinal center of the long side wall bulges inward. The longitudinal center of the battery cell easily expands when the battery cell expands thermally, and the thermal expansion of the battery cell can be effectively suppressed by making the longitudinal center of the long side wall contact the battery cell group.

[0009] The battery module according to claim 3 is based on claim 2, wherein a longitudinal center portion of the long-side side wall portion is in contact with the battery cell group in a no-load state.

[0010] In the battery module according to claim 3, since the long-side side wall portions are in contact with the battery cell group in the no-load state, the long-side side wall portions can apply restraint pressure to the battery cell group.

[0011] A battery module according to claim 4 is based on claim 1, wherein a central portion in the longitudinal direction of the long-side side wall portion is formed thicker than other portions.

[0012] In the battery module according to the fourth embodiment, the longitudinal center of the long side wall is thick, so it is stronger than other parts. This makes it possible to well withstand the force from the battery cell when the battery cell expands thermally, and reduce the weight compared to the case where the long side wall is made thick as a whole.

[0013] The battery module according to claim 5 is based on claim 1, wherein a connection portion between the long-side side wall portion and the short-side side wall portion is formed thicker than other portions.

[0014] In the battery module involved in Scheme 5, since the connecting portion between the long side wall portion and the short side wall portion is thicker than other portions, deformation can be suppressed even if load is input from the battery cell to the long side wall portion during thermal expansion and the load is concentrated on the connecting portion between the long side wall portion and the short side wall portion.

[0015] As described above, according to the battery module according to the present invention, it is possible to suppress thermal expansion while suppressing an increase in manufacturing man-hours and costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals represent like elements, and in which:

[0017] Figure 1 It is a schematic plan view showing a main part of a vehicle to which the battery pack according to the first embodiment is applied.

[0018] Figure 2 It is a schematic perspective view of a battery module according to the first embodiment.

[0019] Figure 3This is a schematic diagram of a battery cell housed in the battery module according to the first embodiment, as viewed from the thickness direction.

[0020] Figure 4 It is a plan view of the battery module according to the first embodiment with the upper cover removed.

[0021] Figure 5 It is a plan view of a battery module according to the second embodiment with the upper cover removed.

[0022] Figure 6 It is a plan view of a battery module according to a third embodiment with an upper cover removed. DETAILED DESCRIPTION

[0023] <First Embodiment>

[0024] A battery module 11 according to a first embodiment will be described with reference to the drawings.

[0025] (Overall Structure of Vehicle 100)

[0026] Figure 1 1 is a schematic plan view showing the main parts of a vehicle 100 to which the battery module 11 according to the present embodiment is applied. Figure 1 As shown, the vehicle 100 is an electric vehicle (BEV) equipped with a battery pack 10 under the floor. In addition, the arrows UP, FR, and LH in each figure respectively indicate the upper side in the vehicle vertical direction, the front side in the vehicle front-back direction, and the left side in the vehicle width direction. When the front-back, left-right, up-down and left-right directions are used for explanation, unless otherwise specified, they indicate the front-back direction in the vehicle front-back direction, the left-right direction in the vehicle width direction, and the up-down direction in the vehicle vertical direction.

[0027] In the vehicle 100 of the present embodiment, as an example, 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. In addition, 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.

[0028] The DC current output from battery pack 10 is regulated in voltage by DC / DC converter 102 and then supplied to electric compressor 104, PTC heater 106, inverter 112, etc. In addition, by supplying electric power to motor 108 via inverter 112, the rear wheels rotate and vehicle 100 travels.

[0029] A charging port 116 is provided on the right side of the rear portion of the vehicle 100 . By connecting a charging plug of an external charging device (not shown) to the charging port 116 , electric power can be stored in the battery pack 10 via the on-vehicle charger 114 .

[0030] In addition, the configuration and structure of each component constituting the vehicle 100 are not limited to the above-mentioned configuration. For example, it can also be applied to a hybrid vehicle (HV: Hybrid Vehicle) or a plug-in hybrid vehicle (PHEV: Plug-in Hybrid Electric Vehicle) equipped with an engine. In addition, in the present embodiment, the motor 108 is mounted on the rear of the vehicle to drive the rear wheels, but it is not limited to this. It can also be a front-wheel drive vehicle with the motor 108 mounted on the front of the vehicle, and a pair of motors 108 can be mounted on the front and rear of the vehicle. Furthermore, it can also be a vehicle with a hub motor (In-wheel Motor) on each wheel.

[0031] Here, the battery pack 10 is configured to include a plurality of battery modules 11. In the present embodiment, as an example, 10 battery modules 11 are provided. Specifically, on the right side of the vehicle 100, five battery modules 11 are arranged in the vehicle front-rear direction, and on the left side of the vehicle 100, five battery modules 11 are arranged in the vehicle front-rear direction. In addition, each battery module 11 is electrically connected.

[0032] Figure 2 1 is a schematic three-dimensional diagram of the battery module 11. Figure 2 As shown, the battery module 11 is formed into a substantially rectangular parallelepiped shape with the vehicle width direction as the length direction. In addition, the housing 13 of the battery module 11 is formed of an aluminum alloy. For example, the housing 13 of the battery module 11 is formed by joining an aluminum alloy die casting to both ends of an aluminum alloy extrusion material by laser welding or the like.

[0033] 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 described later is connected to the connector 14. Bus bars (not shown) are welded to both ends of the battery module 11 in the vehicle width direction.

[0034] The battery module 11 has a length MW in the vehicle width direction of, for example, 350 mm to 600 mm, a length ML in the vehicle front-rear direction of, for example, 150 mm to 250 mm, and a height MH in the vehicle vertical direction of, for example, 80 mm to 110 mm.

[0035] Figure 3 2 is a schematic diagram of a battery cell 20 housed in a battery module 11 as viewed from the thickness direction. Figure 3As shown, the battery cell 20 is formed in a substantially rectangular plate shape, and houses a long electrode body 19 inside. The electrode body 19 is formed by stacking a positive electrode, a negative electrode, and a separator, and is sealed by a laminate film 22 .

[0036] In this embodiment, as an example, the sheet-shaped laminate film 22 processed by stamping is folded and bonded to form the housing portion of the electrode body 19. In addition, two structures, a single cup stamping structure with stamping processing at one place and a double cup stamping structure with stamping processing at two places, can be adopted, but in this embodiment, a single cup stamping structure with a stretching depth of about 8mm to 10mm is adopted.

[0037] The upper ends of both ends of the battery cell 20 in the longitudinal direction are bent to form corners. In addition, the upper end of the battery cell 20 is bent, and a fixing band 24 is wound around the upper end of the battery cell 20 along the longitudinal direction.

[0038] Here, terminals (tabs) 26 are provided at both ends in the longitudinal direction of the battery cell 20. In the present embodiment, as an example, the terminals 26 are provided at positions offset downward from the vertical center of the battery cell 20. The terminals 26 are joined to bus bars (not shown) by laser welding or the like.

[0039] 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 region accommodating 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. Therefore, the battery cell 20 is formed in an elongated shape, and the directions of the lengths CW1 and CW2 are the longitudinal directions.

[0040] In addition, the thickness of the battery cell 20 is 7.0 mm to 9.0 mm, and the height TH of the terminal 26 is 40 mm to 50 mm.

[0041] Figure 4 FIG. 1 is a top view of the battery module 11 according to the first embodiment with the upper cover removed. Figure 4 As shown, a battery cell group in which a plurality of battery cells 20 are arranged is housed inside the battery module 11. In the present embodiment, as an example, 24 battery cells 20 are arranged in the vehicle front-rear direction and bonded to each other.

[0042] A flexible printed circuit (FPC) 21 is disposed on the battery cell 20. The flexible printed circuit 21 is formed in a strip shape with the vehicle width direction as the longitudinal direction, and thermistors 23 are provided at both ends of the flexible printed circuit 21. The thermistor 23 is not bonded to the battery cell 20 and is pressed toward the battery cell 20 by the upper cover of the battery module 11.

[0043] In addition, one or more buffer plates (not shown) are accommodated inside the battery module 11. For example, the buffer plate is a thin plate-shaped member that can be elastically deformed, and is arranged between adjacent battery cells 20 with the arrangement direction of the battery cells 20 as the thickness direction. In this embodiment, as an example, buffer materials are arranged at both ends in the longitudinal direction and the central part in the longitudinal direction of the battery module 11, but buffer materials may not be arranged.

[0044] Here, the shell 13 is constructed to include 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 to each other, and the long side wall portions 13B are formed into a shape that is difficult to deform in the plate thickness direction relative to the short side wall portions 13A.

[0045] Specifically, the pair of short side wall portions 13A constituting the housing 13 are each formed to be approximately straight in a plan view (in a plan view). On the other hand, the pair of long side wall portions 13B are each formed to be convex inward in the central portion in the longitudinal direction. That is, the pair of long side wall portions 13B are each recessed in the opposite directions.

[0046] In the present embodiment, the longitudinal center portion of the long side wall portion 13B is in contact with the battery cell 20 (battery cell group) in the no-load state, and the battery cell group is restrained from both sides by the long side wall portion 13B.

[0047] (effect)

[0048] Next, the operation of the battery module 11 according to the present embodiment will be described.

[0049] In the battery module 11 involved in the present embodiment, the battery cell 20 is formed by encapsulating the electrode body 19 with a laminate film 22, and has a long shape. In addition, the housing 13 can accommodate a battery cell group in which a plurality of battery cells 20 are arranged. Here, the long side wall portion 13B of the housing 13 is formed into a shape that is difficult to deform in the plate thickness direction relative to the short side wall portion 13A. As a result, when the battery cell 20 undergoes thermal expansion, a reaction force is applied to the battery cell 20 from the long side wall portion 13B of the housing 13, thereby suppressing the thermal expansion of the battery cell 20. In addition, since the long side wall portion 13B of the housing 13 is made into a shape that is difficult to deform in the plate thickness direction to suppress the thermal expansion of the battery cell 20, a dedicated component such as a heat shrinkable protective layer is not required. That is, according to the battery module 11 of the present embodiment, thermal expansion can be suppressed while suppressing the increase in manufacturing man-hours and costs.

[0050] In addition, in the present embodiment, the longitudinal center of the long side wall 13B is convex inward. Here, the longitudinal center of the battery cell 20 is easy to expand when the battery cell 20 is thermally expanded, so the longitudinal center of the long side wall 13B is in contact with the battery cell group, thereby effectively suppressing the thermal expansion of the battery cell 20.

[0051] In particular, in the present embodiment, since the long-side side wall portions 13B are in contact with the battery cells 20 (battery cell group) in the no-load state, the long-side side wall portions 13B can apply restraint pressure to the battery cell group.

[0052] <Second Embodiment>

[0053] Next, refer to Figure 5 A battery module 50 according to the second embodiment will be described. Note that the same reference numerals are used for the same configurations as those of the first embodiment, and description thereof will be omitted as appropriate.

[0054] Figure 5 FIG. 2 is a top view of the battery module 50 in this embodiment with the upper cover removed. Figure 5 As shown, in the present embodiment, the longitudinal center portion of the long-side side wall portion 13B is formed thicker than other portions.

[0055] Specifically, the case 13 of the battery module 50 of the present embodiment includes a pair of short-side side walls 13A formed in a substantially linear shape in plan view (in plan view) and a pair of long-side side walls 13B formed in a substantially linear shape in plan view.

[0056] Here, the long side wall portion 13B is formed with a thick wall portion 52 in the central portion in the longitudinal direction. The thick wall portion 52 is formed to be thicker than other portions. Therefore, the long side wall portion 13B is formed in a shape that is convex inward in the central portion in the longitudinal direction. In addition, the thick wall portion 52 contacts the battery cell 20 in the unloaded state.

[0057] (effect)

[0058] Next, the operation of the battery module 50 according to the present embodiment will be described.

[0059] In this embodiment, the thick wall portion 52 in the longitudinal center of the long side wall portion 13B is thick, so it is stronger than other parts. As a result, it is possible to well withstand the force from the battery cell 20 when the battery cell 20 is thermally expanded, and the weight can be reduced compared to the case where the long side wall portion 13B is made thick as a whole. The other effects are the same as those of the first embodiment.

[0060] <Third Embodiment>

[0061] Next, refer to Figure 6A battery module 60 according to a third embodiment will be described. Note that the same components as those of the first embodiment are denoted by the same reference numerals and description thereof will be omitted as appropriate.

[0062] Figure 6 FIG. 2 is a top view of the battery module 60 in this embodiment with the upper cover removed. Figure 6 As shown, in the present embodiment, the connection portion between the long-side side wall portion 13B and the short-side side wall portion 13A is formed thicker than other portions.

[0063] Specifically, the case 13 of the battery module 60 of the present embodiment includes a pair of short side walls 13A formed substantially linearly in a plan view (in a plan view) and a pair of long side walls 13B connecting the short side walls 13A.

[0064] Here, the long side wall portion 13B is formed in a shape in which the outer surface is recessed toward the stacking direction of the battery cells 20. In addition, the inner surface of the long side wall portion 13B is substantially parallel to the battery cells 20. Therefore, the long side wall portion 13B is formed in a shape in which the thickness increases from the center portion in the longitudinal direction to the end portion, and the portion connecting the long side wall portion 13B with the short side wall portion 13A is the thickest.

[0065] (effect)

[0066] Next, the operation of the battery module 60 according to the present embodiment will be described.

[0067] In this embodiment, since the connection portion between the long side wall portion 13B and the short side wall portion 13A is thicker than other portions, even if a load is input 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 on the connection portion between the long side wall portion 13B and the short side wall portion 13A, deformation can be suppressed. Other effects are the same as those of the first embodiment.

[0068] The battery modules 11, 50, and 60 involved in the embodiments are described above, but the present invention is not limited thereto and can be implemented in various ways without departing from the gist of the present invention. For example, in the above-mentioned embodiments, the longitudinal center of the long side wall portion 13B is in contact with the battery cell 20 in the no-load state, but the present invention is not limited thereto and the long side wall portion may be configured not to be in contact with the battery cell.

[0069] In the first embodiment, the longitudinal central portion of the long side wall portion 13B is formed into a shape that is convex inward, but the present invention is not limited thereto and may be formed into other shapes. For example, the long side wall portion 13B may be formed into a shape in which a portion of the long side wall portion that is offset toward the end side from the longitudinal central portion is convex inward.

[0070] The following supplementary notes are disclosed with respect to the above-mentioned embodiment.

[0071] (Note 1)

[0072] A battery module comprising:

[0073] A long battery cell formed by encapsulating an electrode body with a laminate film; and

[0074] The housing can accommodate a battery cell group formed by arranging a plurality of battery cells.

[0075] The housing is configured to include a pair of short-side wall portions extending along the stacking direction of the battery cells and a pair of long-side wall portions connecting the short-side wall portions to each other.

[0076] The long-side side wall portion is formed into a shape that is less likely to deform in the plate thickness direction than the short-side side wall portion.

[0077] (Note 2)

[0078] According to the battery module described in Supplementary Note 1,

[0079] The short side wall portion is formed in a straight line shape,

[0080] The long side wall portion is formed in a shape in which a central portion in the longitudinal direction is convex inward.

[0081] (Note 3)

[0082] The battery module according to Supplement 1 or 2,

[0083] A longitudinal center portion of the long-side side wall portion is in contact with the battery cell group in a no-load state.

[0084] (Note 4)

[0085] The battery module according to any one of Supplementary Notes 1 to 3,

[0086] The longitudinal center portion of the long side wall portion is formed to be thicker than other portions.

[0087] (Note 5)

[0088] According to the battery module described in Supplementary Note 1,

[0089] The connection portion between the long-side side wall portion and the short-side side wall portion is formed thicker than other portions.

Claims

1. A battery module comprising: A long battery cell formed by encapsulating an electrode body with a laminate film; and The housing can accommodate a battery cell group formed by arranging a plurality of battery cells. The housing is configured to include a pair of short-side wall portions extending along the stacking direction of the battery cells and a pair of long-side wall portions connecting the short-side wall portions to each other. The long-side side wall portion is formed into a shape that is less likely to deform in the plate thickness direction than the short-side side wall portion.

2. The battery module according to claim 1, The short side wall portion is formed in a straight line shape, The long side wall portion is formed in a shape in which a central portion in the longitudinal direction is convex inward.

3. The battery module according to claim 2, A longitudinal center portion of the long-side side wall portion is in contact with the battery cell group in a no-load state.

4. The battery module according to claim 1, The longitudinal center portion of the long side wall portion is formed to be thicker than other portions.

5. The battery module according to claim 1, The connection portion between the long-side side wall portion and the short-side side wall portion is formed thicker than other portions.

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