Battery module and battery pack

Abstract

To provide a battery module and a battery pack in which the state of thermal expansion-shrinkage of battery cells can be precisely detected.SOLUTION: A battery module 11 includes: a long battery cell 20 formed by sealing an electrode body with a laminate film; a case 13 for storing a battery cell group in which the battery cells 20 are arranged; and a strain sensor 30 provided in at least one of the battery cell 20 and the case 13, the strain sensor detecting a strain.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a battery module and a battery pack. [Background technology]

[0002] Patent Document 1 discloses a battery module in which an electrode assembly is housed in a case. The outside of the electrode assembly (battery cell) is surrounded by a heat-shrinkable protective layer, thereby suppressing 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 [Problem to be solved by the invention]

[0004] Incidentally, although it is possible to indirectly detect the thermal expansion / contraction state of the battery cells based on information such as voltage output from the battery module, there is room for improvement in terms of improving the detection accuracy.

[0005] SUMMARY OF THE PRESENT INVETION The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a battery module and a battery pack that are capable of detecting the thermal expansion and contraction state of battery cells with high accuracy. [Means for solving the problem]

[0006] The battery module of claim 1 comprises a long battery cell formed by sealing an electrode body with a laminate film, a case capable of accommodating a battery cell group in which a plurality of the battery cells are arranged, and a strain sensor provided in at least one of the battery cell and the case and capable of detecting strain.

[0007] In the battery module according to claim 1, a long battery cell is formed by sealing the electrode body with a laminate film. The case is configured to be capable of housing a battery cell group in which a plurality of battery cells are arranged. At least one of the battery cell and the case is provided with a strain sensor capable of detecting strain. This makes it possible to directly detect the thermal expansion and contraction state of the battery cell by acquiring a signal from the strain sensor during thermal expansion and contraction.

[0008] The battery module of claim 2 is the same as claim 1, wherein the case includes 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, and the strain sensor is provided at least in the center of the long side wall portions.

[0009] In the battery module according to claim 2, the case includes a pair of short side wall portions and a pair of long side wall portions. The strain sensor is provided at least in the center of the long side wall portions. Here, the displacement due to thermal expansion and contraction is greater in the long side wall portions than in the short side wall portions, and the displacement is greater in the center of the long side wall portions than in the ends. Thus, by providing the strain sensor in the center of the long side wall portions where the displacement due to thermal expansion and contraction is greater, the thermal expansion and contraction state can be detected with high accuracy.

[0010] The battery module according to claim 3 is based on claim 2, and the long-side side wall portion is formed in a shape in which the longitudinal center portion is convex inward.

[0011] In the battery module according to claim 3, the central portion in the longitudinal direction of the long side wall portion is convex inward, so that by providing the strain sensor in this central portion, the strain sensor does not interfere with surrounding components.

[0012] A battery module according to a fourth aspect of the present invention is the battery module according to the first aspect, wherein the strain sensor is provided at least in a central portion in a longitudinal direction of the battery cell.

[0013] In the battery module according to claim 4, the strain sensor is provided in the center of the battery cell in the longitudinal direction, so that the thermal expansion and contraction state of the battery cell can be directly detected by acquiring a signal from the strain sensor.

[0014] A battery module according to a fifth aspect of the present invention is based on the first aspect, wherein the battery cell includes a housing portion that houses the electrode body, and the strain sensor is provided at least at an end of the housing portion.

[0015] In the battery module according to claim 5, the battery cell includes a housing portion that houses the electrode assembly. The strain sensor is provided at an end of the housing portion. Since the end of the housing portion is a location that experiences large displacement during thermal expansion and contraction of the battery cell, providing the strain sensor at this location makes it possible to accurately detect the thermal expansion and contraction state.

[0016] A battery pack according to a sixth aspect of the present invention is configured by arranging a plurality of the battery modules according to any one of the first to fifth aspects.

[0017] In the battery pack according to claim 6, a plurality of battery modules are arranged, whereby the thermal expansion and contraction states of the plurality of battery modules can be grasped. Effect of the Invention

[0018] As described above, the battery module and battery pack according to the present invention can accurately detect the thermal expansion and contraction state of the battery cells. [Brief description of the drawings]

[0019] [Figure 1] 1 is a schematic plan view showing a main part of a vehicle to which a battery pack according to a first embodiment is applied. [Diagram 2] FIG. 2 is a schematic perspective view of a battery module. [Diagram 3] 3 is a schematic diagram of a battery cell accommodated in a battery module as viewed from the thickness direction. FIG. [Figure 4]FIG. 1A is a plan view of the battery module with the top cover removed, and FIG. 1B is a plan view showing the battery module in a thermally expanded state. [Diagram 5] FIG. 13(A) is a schematic diagram showing a battery cell in a first modified example, and FIG. 13(B) is a schematic diagram showing a battery cell in a second modified example. [Figure 6] FIG. 13 is a plan view of a battery module according to a third modified example with its top cover removed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] First Embodiment A battery module 11 according to a first embodiment will be described with reference to the drawings.

[0021] (Overall configuration of vehicle 100) Fig. 1 is a schematic plan view showing a main part of a vehicle 100 to which a battery pack 10 according to this embodiment is applied. As shown in Fig. 1, the vehicle 100 is an electric vehicle (BEV: Battery Electric Vehicle) in which the battery pack 10 is mounted under the floor. Note that the arrows UP, FR, and LH in each figure indicate the upper side in the vehicle vertical direction, the front side in the vehicle longitudinal direction, and the left side in the vehicle width direction, respectively. When describing using the front-rear, left-right, up-down directions, they refer to the front-rear in the vehicle longitudinal direction, the left-right in the vehicle width direction, and the up-down in the vehicle vertical direction, unless otherwise specified.

[0022] As an example, in the vehicle 100 of this embodiment, a DC / DC converter 102, an electric compressor 104, and a PTC (Positive Temperature Coefficient) heater 106 are disposed on the vehicle front side of the battery pack 10. In addition, a motor 108, a gear box 110, an inverter 112, and a charger 114 are disposed on the vehicle rear side of the battery pack 10.

[0023] The direct current output from the battery pack 10 has its voltage adjusted by a DC / DC converter 102, and is then supplied to an electric compressor 104, a PTC heater 106, an inverter 112, etc. In addition, power is supplied to a motor 108 via the inverter 112, causing the rear wheels to rotate and causing the vehicle 100 to run.

[0024] A charging port 116 is provided on the right side at the rear of the vehicle 100, and by connecting a charging plug of an external charging device (not shown) to the charging port 116, power can be stored in the battery pack 10 via the on-board charger 114.

[0025] The arrangement and structure of each component constituting the vehicle 100 are not limited to the above-mentioned configuration. For example, the present invention may be applied to a hybrid vehicle (HV: Hybrid Vehicle) equipped with an engine or a plug-in hybrid vehicle (PHEV: Plug-in Hybrid Electric Vehicle). In addition, in the present embodiment, the vehicle is a rear-wheel drive vehicle in which the motor 108 is mounted at the rear of the vehicle, but the present invention is not limited to this. The vehicle may be a front-wheel drive vehicle in which the motor 108 is mounted at the front of the vehicle, or a pair of motors 108 may be mounted at the front and rear of the vehicle. Furthermore, the vehicle may be equipped with an in-wheel motor on each wheel.

[0026] Here, the battery pack 10 is configured to include a plurality of battery modules 11. As an example in this embodiment, ten battery modules 11 are provided. Specifically, five battery modules 11 are arranged on the right side of the vehicle 100 in the vehicle front-rear direction, and five battery modules 11 are arranged on the left side of the vehicle 100 in the vehicle front-rear direction. In addition, each battery module 11 is electrically connected.

[0027] Fig. 2 is a schematic perspective view of the battery module 11. As shown in Fig. 2, the battery module 11 is formed in a substantially rectangular parallelepiped shape with the vehicle width direction as the longitudinal direction. The case 13 of the battery module 11 is formed of an aluminum alloy. For example, the case 13 of the battery module 11 is formed by joining aluminum die castings to both ends of an extruded aluminum alloy material by laser welding or the like.

[0028] 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, bus bars (not shown) are welded to both ends of the battery module 11 in the vehicle width direction.

[0029] 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 front-rear direction is, for example, 150 mm to 250 mm, and the height MH in the vehicle up-down direction is, for example, 80 mm to 110 mm.

[0030] Fig. 3 is a schematic diagram of a battery cell 20 housed in a battery module 11, viewed from the thickness direction. As shown in Fig. 3, the battery cell 20 is formed in a substantially rectangular plate shape, and houses a long electrode body 19 therein. The electrode body 19 is configured by laminating a positive electrode, a negative electrode, and a separator, and is sealed with a laminate film 22.

[0031] In this embodiment, as an example, an embossed sheet-like laminate film 22 is folded and bonded to form a housing portion for the electrode body 19. Note that although both a single cup embossed structure in which one portion is embossed and a double cup embossed structure in which two portions are embossed can be adopted, the present embodiment employs a single cup embossed structure with a drawing depth of about 8 mm to 10 mm.

[0032] The upper ends of the battery cells 20 at both ends in the longitudinal direction are bent to form corners. The upper end of the battery cells 20 is also bent, and a fixing tape 24 is wound around the upper end of the battery cells 20 along the longitudinal direction.

[0033] 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 positions offset downward from the vertical center of the battery cell 20. The terminals 26 are joined to a bus bar (not shown) by laser welding or the like.

[0034] 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 in which the electrode body 19 is housed 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 direction of the lengths CW1 and CW2 is the longitudinal direction.

[0035] 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.

[0036] Fig. 4(A) is a plan view of the battery module 11 with the top cover removed. As shown in Fig. 4(A), a battery cell group in which a plurality of battery cells 20 are arranged is housed inside the battery module 11. In this embodiment, as an example, 24 battery cells 20 are arranged in the front-rear direction of the vehicle and bonded to one another.

[0037] A flexible printed circuit (FPC) 21 is disposed on the battery cells 20. The flexible printed circuit 21 is formed in a strip shape with the vehicle width direction as the longitudinal direction, and a thermistor 23 is provided on each of both ends of the flexible printed circuit 21. The thermistor 23 is not bonded to the battery cells 20, and is configured to be pressed towards the battery cells 20 by the upper lid of the battery module 11.

[0038] One or more buffer plates (not shown) are housed inside the battery module 11. For example, the buffer plate is an elastically deformable thin plate member, and is disposed between adjacent battery cells 20 with the arrangement direction of the battery cells 20 being the thickness direction. As an example in this embodiment, buffer materials are disposed at both ends of the battery module 11 in the longitudinal direction and at the center portion in the longitudinal direction.

[0039] Here, a strain sensor 30 capable of detecting strain is provided in the case 13 of the battery module 11. Specifically, the case 13 is configured 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.

[0040] The strain sensor 30 is provided at least in the center of the long side wall portion 13B of the case 13. In the present embodiment, as an example, the strain sensor 30 is provided in the center of the long side wall portion 13B in the longitudinal direction and in the height direction. Moreover, the strain sensor 30 in the present embodiment is provided on each of the pair of long side wall portions 13B.

[0041] The strain sensor 30 is, for example, a sensor that utilizes the principle that a resistor expands and contracts in proportion to the expansion and contraction of the object to be measured by adhering it to the object to be measured via an electrical insulator, and the resistance value changes. The strain sensor 30 is also connected to lead wires (not shown), and is configured so that the signal output from the strain sensor 30 can be acquired by an external device.

[0042] Fig. 4(B) is a plan view showing a state in which the battery module 11 has thermally expanded from the state shown in Fig. 4(A). For ease of explanation, the expansion of the case 13 is exaggerated. As shown in Fig. 4(B), when the battery cell 20 thermally expands, it expands in the plate thickness direction, causing the long side wall portion 13B of the case 13 to expand. At this time, the thermal expansion and contraction state of the case 13 can be grasped by acquiring the signal output from the strain sensor 30.

[0043] In this embodiment, the strain sensor 30 is provided on the long side wall portion 13B of the case 13, but the present invention is not limited to this, and the strain sensor 30 may be provided on the battery cell 20 as in the first and second modified examples shown in Figures 5(A) and 5(B). Also, the shape of the case 13 may be changed as in the third modified example shown in Figure 6.

[0044] (First Modification) Fig. 5(A) is a schematic diagram showing a battery cell 20 in a first modified example. As shown in Fig. 5(A), the laminate film 22 constituting the battery cell 20 has a single-cup embossed structure and includes an accommodating portion 22A (embossed portion) that accommodates the electrode body 19.

[0045] A strain sensor 30 is provided at the center of the housing section 22A in the longitudinal direction of the battery cell 20. By acquiring a signal from the strain sensor 30, the expansion state of the housing section 22A can be grasped.

[0046] (Second Modification) Fig. 5(B) is a schematic diagram showing a battery cell 20 in a first modified example. As shown in Fig. 5(B), in this modified example, a strain sensor 30 is provided at the end of the storage section 22A. That is, the strain sensor 30 is provided at the shoulder of the embossed cup.

[0047] (Third Modification) Fig. 6 is a plan view of a battery module according to a third modified example with the top cover removed. As shown in Fig. 6, in this modified example, the long side wall portion 13B of the case 13 is recessed. Specifically, the long side wall portion 13B is formed in a shape in which the longitudinal center portion is convex inward. In addition, a strain sensor 30 is provided in the longitudinal center portion of the long side wall portion 13B.

[0048] In this modification, since the strain sensor 30 is provided in the recessed portion, even when a plurality of battery modules 11 are arranged, the strain sensor 30 can be prevented from interfering with adjacent battery modules.

[0049] (action) Next, the operation of the battery pack 10 and the battery module 11 according to this embodiment will be described.

[0050] In the battery module 11 according to this embodiment, as shown in FIG. 3, an elongated battery cell 20 is formed by sealing an electrode body 19 with a laminate film 22. Also, as shown in FIG. 4(A), the case 13 is configured to be capable of housing a battery cell group in which a plurality of battery cells 20 are arranged. Furthermore, the case 13 is provided with a strain sensor 30 capable of detecting strain. As a result, the thermal expansion and contraction state of the battery cell 20 can be directly detected by acquiring a signal from the strain sensor 30 during thermal expansion and contraction. As a result, the thermal expansion and contraction state of the battery cell 20 can be detected with high accuracy. In the battery pack 10, a plurality of battery modules 11 are arranged. As a result, the thermal expansion and contraction states of the plurality of battery modules 11 can be grasped.

[0051] In this embodiment, the case 13 includes a pair of short side wall portions 13A and a pair of long side wall portions 13B, and the strain sensor 30 is provided at least in the center of the long side wall portion 13B. As shown in Fig. 4B, the displacement due to thermal expansion and contraction is larger in the long side wall portion 13B than in the short side wall portion 13A, and the displacement is larger in the center of the long side wall portion 13B than in the end portion. Thus, by providing the strain sensor 30 in the center of the long side wall portion 13B where the displacement due to thermal expansion and contraction is larger, the thermal expansion and contraction state can be detected with high accuracy.

[0052] Furthermore, in the first modified example, as shown in FIG. 5(A), a strain sensor 30 is provided in the center of the longitudinal direction of the battery cell 20, so that the thermal expansion and contraction state of the battery cell 20 can be directly detected by acquiring a signal from the strain sensor 30.

[0053] 5(B), in the second modified example, a strain sensor 30 is provided at the end of the housing portion 22A of the battery cell 20. Here, the end of the housing portion 22A, i.e., the shoulder of the embossed cup, is a portion that experiences large displacement when the battery cell 20 thermally expands and contracts, so by providing the strain sensor 30 at this portion, the thermal expansion and contraction state can be detected with high accuracy.

[0054] Furthermore, in the third modified example, as shown in FIG. 6, the longitudinal center portion of the long side wall portion 13B of the case 13 is convex inward, so that by providing the strain sensor 30 in this center portion, the strain sensor 30 does not interfere with surrounding components such as adjacent battery modules.

[0055] Although the battery pack 10 and the battery module 11 according to the embodiment have been described above, the present invention is not limited thereto, and may be embodied in various forms without departing from the spirit and scope of the present invention. For example, in the above embodiment, the strain sensor 30 is provided at the center in the height direction of the long side wall portion 13B, but the present invention is not limited thereto, and the position in the height direction at which the strain sensor 30 is attached may be changed.

[0056] Furthermore, as the strain sensor, strain sensors of various configurations can be used as long as they are configured to be able to detect strain in the case 13 and the battery cell 20.

[0057] Furthermore, the strain sensor 30 may be provided in both the case 13 and the battery cell 20. In this case, the strain sensor provided in the case 13 and the strain sensor provided in the battery cell 20 may be different types of sensors. For example, the strain sensor provided in the battery cell 20 may be one with a thinner shape.

[0058] Furthermore, although the above embodiment employs a single-cup embossed structure, the present invention is not limited to this and may be applied to a battery cell having a double-cup embossed structure. In this case, a strain sensor can be provided in one or both of the embossed cups to detect the thermal expansion state of the battery cell.

[0059] Regarding the above embodiment, the following notes are disclosed.

[0060] (Appendix 1) a long battery cell formed by sealing the electrode body with a laminate film; a case capable of accommodating a battery cell group in which a plurality of the battery cells are arranged; a strain sensor provided in at least one of the battery cell and the case and capable of detecting a strain; A battery module having (Appendix 2) the case is configured to include a pair of short side wall portions extending along a stacking direction of the battery cells and a pair of long side wall portions connecting the short side wall portions, 2. The battery module according to claim 1, wherein the strain sensor is provided at least in a central portion of the long side wall portion. (Appendix 3) The battery module according to claim 1 or 2, wherein the long-side side wall portion is formed so that a longitudinal center portion thereof is convex inwardly. (Appendix 4) The battery module according to any one of claims 1 to 3, wherein the strain sensor is provided at least in a central portion in a longitudinal direction of the battery cell. (Appendix 5) The battery cell includes a housing portion that houses the electrode assembly, 5. The battery module according to claim 4, wherein the strain sensor is provided at least at an end of the storage portion. (Appendix 6) A battery pack comprising a plurality of battery modules according to any one of claims 1 to 5 arranged in an array. [Explanation of symbols]

[0061] 10 Battery pack 11 Battery module 13 Cases 13A Short side wall 13B Long side wall 19 Electrode body 20 Battery Cells 22 Laminating film 22A Storage section 30 Strain Sensor

Claims

1. a long battery cell formed by sealing the electrode body with a laminate film; a case capable of accommodating a battery cell group in which a plurality of the battery cells are arranged; a strain sensor provided in at least one of the battery cell and the case and capable of detecting a strain; A battery module having

2. the case is configured to include a pair of short side wall portions extending along a stacking direction of the battery cells and a pair of long side wall portions connecting the short side wall portions, The battery module according to claim 1 , wherein the strain sensor is provided at least in a central portion of the long side wall portion.

3. The battery module according to claim 2 , wherein the long-side sidewall portion has a longitudinal center portion formed into a shape that is convex inward.

4. The battery module according to claim 1 , wherein the strain sensor is provided at least in a central portion of the battery cell in a longitudinal direction.

5. The battery cell includes a housing portion that houses the electrode assembly, The battery module according to claim 4 , wherein the strain sensor is provided at least at an end of the housing portion.

6. A battery pack comprising a plurality of battery modules according to any one of claims 1 to 5 arranged in an array.

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