Battery module, battery pack and vehicle comprising the same

Abstract

A battery module of the disclosure includes: a battery cell stack including a plurality of battery cells; first and second end plates covering top and bottom surfaces of the battery cell stack, respectively; first and second upper reinforcement plates located on the first end plate and extending from one side and the other side of the first end plate toward the middle of the first end plate in the length direction of the first end plate, respectively; first and second lower reinforcement plates located on the second end plate and extending from one side and the other side of the second end plate toward the middle of the second end plate in the length direction of the second end plate, respectively; a first fastening bolt located on one side of the battery cell stack in the length direction of the battery cell stack and passing through the first upper reinforcement plate, the first end plate, the second end plate, and the first lower reinforcement plate; and a second fastening bolt located on the other side of the battery cell stack in the length direction of the battery cell stack and passing through the second upper reinforcement plate, the first end plate, the second end plate, and the second lower reinforcement plate.

Description

Technical Field

[0001] This disclosure relates to a battery module having a structure capable of absorbing expansion, as well as a battery pack and a vehicle including the battery module. More specifically, it relates to a battery module having a structure capable of effectively absorbing the expansion of individual battery cells by improving the bending deformation resistance of the end plates without increasing the thickness of the end plates.

[0002] This application claims priority to Korean Patent Application No. 10-2020-0186475, filed in Korea on December 29, 2020, the disclosure of which is incorporated herein by reference. Background Technology

[0003] In such Figure 1 In the conventional battery module shown, end plates 4 are located on both sides of the battery cell stack 3. The battery cell stack 3 includes battery cells 1 and expansion absorption pads 2 in the stacking direction of the battery cell stack 3, and a pair of end plates 4 are fixed to each other by fastening bolts 5.

[0004] In this battery module structure, the end plate 4 restricts the deformation caused by the expansion of the battery cell 1. The expansion absorption pad 2 is located on the outermost side of the battery cell stack 3 and / or between adjacent battery cells 1 to primarily absorb the deformation caused by the expansion of the battery cell 1.

[0005] Furthermore, when expansion occurs beyond the extent of deformation that the expansion absorption pad 2 can absorb, the volume expansion of the battery cell 1 is limited by the end plate 4. The end plate 4 should have appropriate rigidity so that it does not excessively restrict expansion. To this end, the battery cell 1 should be subjected to expansion tests with repeated charging and discharging, and a verification procedure should be performed based on the test results to prevent structural damage to the battery module.

[0006] As the number of charge and discharge cycles increases, the expansion force applied to the module gradually increases. Therefore, the performance of battery cell 1 may decrease, and the lifespan of battery cell 1 may also decrease. In battery cell 1, when a large expansion force is applied locally, the separator within battery cell 1 may be partially compressed, thereby reducing the performance of battery cell 1. Conversely, when the pressure is too weak, problems may arise due to the generation of gas within battery cell 1.

[0007] In traditional battery module structures, when the thickness of the end plate 4 is reduced to decrease weight, the bending stiffness of the end plate 4 is insufficient. Therefore, due to expansion forces, bending deformation occurs in the portion of the end plate 4 corresponding to the middle of the battery cell 1. This partial deformation of the end plate 4 increases the pressure deviation among the multiple battery cells 1 constituting the battery cell stack 3, and the pressure deviation based on the position within a single battery cell 1, leading to performance degradation of the battery module.

[0008] Therefore, it is necessary to develop a battery module structure that can apply a uniform force to the entire battery cell stack 3 when the battery cell 1 expands. Summary of the Invention

[0009] Technical issues

[0010] This disclosure aims to address the problems of the prior art, and therefore one object of this disclosure is to apply uniform pressure to the battery cell by reducing the amount of bending deformation of the end plate due to expansion without increasing the thickness of the end.

[0011] In addition, another objective of this disclosure is to prevent the pressure applied to the battery cell from increasing excessively due to the reduction in the amount of bending deformation of the end plate.

[0012] However, the technical objectives to be addressed by this invention are not limited to those described above. Those skilled in the art will clearly understand other objectives not mentioned herein through the following disclosure.

[0013] Technical solution

[0014] In one aspect of this disclosure, a battery module is provided, comprising: a battery cell stack including a plurality of battery cells; a first end plate and a second end plate, respectively covering the top and bottom surfaces of the battery cell stack; a first upper reinforcing plate and a second upper reinforcing plate located on the first end plate and extending along the length of the first end plate from one side and the other side toward the center of the first end plate, respectively; a first lower reinforcing plate and a second lower reinforcing plate located on the second end plate and extending along the length of the second end plate from one side and the other side toward the center of the second end plate, respectively; a first fastening bolt located on one side of the battery cell stack along the length of the battery cell stack and passing through the first upper reinforcing plate, the first end plate, the second end plate, and the first lower reinforcing plate; and a second fastening bolt located on the other side of the battery cell stack along the length of the battery cell stack and passing through the second upper reinforcing plate, the first end plate, the second end plate, and the second lower reinforcing plate.

[0015] The first upper reinforcing plate and the second upper reinforcing plate may extend toward each other but may be spaced apart from each other, and the first lower reinforcing plate and the second lower reinforcing plate may extend toward each other but may be spaced apart from each other.

[0016] A pair of first fastening bolts and a pair of second fastening bolts can be respectively disposed at one end and the other end of the battery module along the width direction of the battery module.

[0017] A pair of first upper reinforcing plates and a pair of first lower reinforcing plates can be respectively disposed at one end and the other end of the battery module along the width direction of the battery module, and a pair of second upper reinforcing plates and a pair of second lower reinforcing plates can be respectively disposed at one end and the other end of the battery module along the width direction of the battery module.

[0018] The first upper reinforcing plate and the first lower reinforcing plate can be fastened to the first end plate and the second end plate respectively by a pair of first fastening bolts, and the second upper reinforcing plate and the second lower reinforcing plate can be fastened to the first end plate and the second end plate respectively by a pair of second fastening bolts.

[0019] Each of the first and second fastening bolts may include an upper bolt and a lower bolt spaced apart from each other, wherein the battery module also includes a pressure relief coupler connecting the upper bolt and the lower bolt.

[0020] The pressure-reducing coupling may include: a first main hinge, which is coupled to an upper bolt; a second main hinge, which is coupled to a lower bolt; and a first connecting rod, which is fastened between the first main hinge and the second main hinge.

[0021] The pressure-reducing connector may also include a pair of first sub-connecting rod assemblies, which are respectively disposed on one side and the other side of the first connecting rod and hinged to the first main hinge and the second main hinge.

[0022] Each of the pair of first sub-connecting rod assemblies may include: a pair of first sub-connecting rods, respectively hinged to a first main hinge and a second main hinge; and a first sub-hinge, hinged between the pair of first sub-connecting rods.

[0023] The sum of the lengths of a pair of first sub-connecting rods can be greater than the length of the first connecting rod.

[0024] The pressure-reducing connector may also include a pair of second sub-connecting rod assemblies disposed on one side and the other side of the first connecting rod, located further outward than the first sub-connecting rod assembly, and hinged to the first main hinge and the second main hinge.

[0025] Each of the pair of second sub-connecting rod assemblies may include: a pair of second sub-connecting rods, respectively hinged to a first main hinge and a second main hinge; and a second sub-hinge, hinged between the pair of second sub-connecting rods.

[0026] The sum of the lengths of a pair of second sub-connecting rods can be greater than the sum of the lengths of a pair of first sub-connecting rods.

[0027] In another aspect of this disclosure, a battery pack and a vehicle including a battery module according to embodiments of this disclosure are also provided.

[0028] Beneficial effects

[0029] According to one aspect of this disclosure, uniform pressure can be applied to the battery cell by reducing the amount of bending deformation of the end plate due to expansion without increasing the thickness of the end plate.

[0030] Furthermore, according to another aspect of this disclosure, it is possible to prevent the pressure applied to the battery cell from increasing excessively due to the reduction in the amount of bending deformation of the end plate. Attached Figure Description

[0031] The accompanying drawings illustrate preferred embodiments of the present disclosure and, together with the foregoing disclosure, are intended to provide a further understanding of the technical features of the present disclosure. Therefore, the present disclosure is not to be construed as limited to the drawings.

[0032] Figure 1 This is a diagram showing a conventional battery module.

[0033] Figure 2 This is a side view showing a battery module according to an embodiment of the present disclosure.

[0034] Figure 3 and Figure 4 It is shown Figure 2 A plan view of the battery module.

[0035] Figure 5 This is a side view showing a battery module according to another embodiment of the present disclosure.

[0036] Figure 6 This is a diagram illustrating a pressure-reducing connector applied to a battery module according to another embodiment of the present disclosure. Detailed Implementation

[0037] Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Before description, it should be understood that the terminology used in the specification and appended claims should not be construed as limited to its general or dictionary meaning, but rather interpreted according to the meaning and concept corresponding to the technical aspects of the present disclosure, based on the principle of allowing the inventors to appropriately define the terms for the best interpretation. Therefore, the descriptions presented herein are merely preferred examples and are for illustrative purposes only, and not intended to limit the scope of the present disclosure. Consequently, it should be understood that other equivalents and modifications may be made without departing from the scope of the present disclosure.

[0038] Reference Figure 2 According to embodiments of the present disclosure, the battery module includes a battery cell stack 10, an end plate 20, a reinforcing plate 40, and fastening bolts 30.

[0039] The battery cell stack 10 includes multiple battery cells 11. For example, a pouch cell can be used as the battery cell 11. Although Figure 2 As not shown, the battery cell 11 includes a pair of electrode leads (not shown) extending longitudinally (parallel to the X-axis) to the outside of the battery cell 11. The pair of electrode leads may extend in the same or opposite directions. Multiple battery cells 11 are stacked in the vertical direction (parallel to the Z-axis).

[0040] The battery cell stack 10 may also include an expansion absorption pad 12 located between adjacent battery cells 11 and / or at the outermost position in the stacking direction (parallel to the Z-axis) of the battery cell stack 10. The expansion absorption pad 12 can be squeezed during the expansion of the battery cells 11 due to repeated charging and discharging to absorb the volume expansion of the battery cells 11.

[0041] The end plate 20 includes a first end plate 21 covering the top surface of the battery cell stack 10 and a second end plate 22 covering the bottom surface of the battery cell stack 10. The first end plate 21 and the second end plate 22 have corresponding areas. The area of ​​the first end plate 21 and the second end plate 22 is larger than the area of ​​the battery cell stack 10 to facilitate engagement using fastening bolts 30.

[0042] Each of the first end plate 21 and the second end plate 22 has sufficient rigidity to protect the battery cell stack 10 from external impacts and to suppress volume expansion due to expansion. Considering these functions, each of the first end plate 21 and the second end plate 22 can be formed of a metallic material.

[0043] The reinforcing plate 40 includes a first upper reinforcing plate 41 and a second upper reinforcing plate 42 located on the first end plate 21, and a first lower reinforcing plate 43 and a second lower reinforcing plate 44 located on the second end plate 22.

[0044] The first upper reinforcing plate 41 extends from one side of the first end plate 21 toward the center along the length direction of the first end plate 21 (parallel to the X-axis). The second upper reinforcing plate 42 extends from the other side of the first end plate 21 toward the center along the length direction of the first end plate 21. The first upper reinforcing plate 41 and the second upper reinforcing plate 42 extend toward each other but are spaced apart from each other.

[0045] The first lower reinforcing plate 43 extends from one side of the second end plate 22 toward the center along the length direction of the second end plate 22 (parallel to the X-axis). The second lower reinforcing plate 44 extends from the other side of the second end plate 22 toward the center along the length direction of the second end plate 22. The first lower reinforcing plate 43 and the second lower reinforcing plate 44 extend toward each other but are spaced apart from each other.

[0046] When the battery cell 11 expands, the portion where the volume expansion is concentrated is the middle part of the battery cell 11 in the length direction (parallel to the X-axis). Therefore, each of the first end plate 21 and the second end plate 22 is subjected to concentrated pressure at the middle part in the length direction (parallel to the X-axis).

[0047] The first upper reinforcing plate 41 and the second upper reinforcing plate 42 partially strengthen the rigidity of the first end plate 21, thus reducing the strain of the first end plate 21 due to expansion pressure. Similarly, the first lower reinforcing plate 43 and the second lower reinforcing plate 44 partially strengthen the rigidity of the second end plate 22, thus reducing the strain of the second end plate 22 due to expansion pressure.

[0048] Because the first upper reinforcing plate 41 and the second upper reinforcing plate 42 partially reinforce the first end plate 21, the bending stiffness of the first end plate 21 can be effectively strengthened without significantly increasing the weight of the battery module. Furthermore, because the first upper reinforcing plate 41 and the second upper reinforcing plate 42 are spaced apart from each other and not connected, excessive suppression of volume expansion due to expansion can be prevented. Similarly, because the first lower reinforcing plate 43 and the second lower reinforcing plate 44 partially reinforce the second end plate 22, the bending stiffness of the second end plate 22 can be effectively strengthened without significantly increasing the weight of the battery module. Furthermore, because the first lower reinforcing plate 43 and the second lower reinforcing plate 44 are spaced apart from each other and not connected, excessive suppression of volume expansion due to expansion can be prevented.

[0049] The fastening bolt 30 includes a first fastening bolt 31 located on one side of the battery cell stack 10 along the length direction (parallel to the X-axis) of the battery cell stack 10 and a second fastening bolt 32 located on the other side of the battery cell stack 10 along the length direction of the battery cell stack 10.

[0050] The first fastening bolt 31 passes through one end of each of the first upper reinforcing plate 41, the first end plate 21, the second end plate 22, and the first lower reinforcing plate 43 along its length (parallel to the X-axis). The first end plate 21 and the second end plate 22 are securely fixed to the battery cell stack 10 by the first fastening bolt 31. The first upper reinforcing plate 41 and the first lower reinforcing plate 43 are also securely fixed to the first end plate 21 and the second end plate 22, respectively, by the first fastening bolt 31.

[0051] The second fastening bolt 32 passes along its length (parallel to the X-axis) through the other end of each of the second upper reinforcing plate 42, the first end plate 21, the second end plate 22, and the second lower reinforcing plate 44. The second fastening bolt 32 secures the first end plate 21 and the second end plate 22 tightly to the battery cell stack 10. The second upper reinforcing plate 42 and the second lower reinforcing plate 44 are also securely fixed to the first end plate 21 and the second end plate 22, respectively, by the second fastening bolt 32.

[0052] Reference Figure 3A pair of first fastening bolts 31 and a pair of second fastening bolts 32 can be respectively disposed at one end and the other end of the battery module along the width direction of the battery module (parallel to the Y-axis). In this case, a pair of first upper reinforcing plates 41 and a pair of first lower reinforcing plates 43 can be respectively disposed at one end and the other end of the battery module along the width direction of the battery module. Similarly, a pair of second upper reinforcing plates 42 and a pair of second lower reinforcing plates 44 can be respectively disposed at one end and the other end of the battery module along the width direction of the battery module.

[0053] Reference Figure 2 and Figure 4 ,and Figure 3 In contrast, a first upper reinforcing plate 41 and a first lower reinforcing plate 43 may be disposed at one end of the battery module along the length direction of the battery module. In this case, each of the first upper reinforcing plate 41 and the first lower reinforcing plate 43 extends from one end of the battery module toward the other end along the width direction of the battery module, and the first end plate 21 and the second end plate 22 are fastened by a pair of first fastening bolts 31.

[0054] Similarly, a second upper reinforcing plate 42 and a second lower reinforcing plate 44 may also be disposed at the other end of the battery module along the length direction of the battery module. In this case, each of the second upper reinforcing plate 42 and the second lower reinforcing plate 44 extends from one end of the battery module toward the other end along the width direction of the battery module, and the first end plate 21 and the second end plate 22 are fastened by a pair of second fastening bolts 32.

[0055] Reference Figure 5 and Figure 6 Each of the first fastening bolt 31 and the second fastening bolt 32 may include an upper bolt 30a and a lower bolt 30b spaced apart from each other. In this case, the battery module may also include a pressure-reducing connector 50 connecting the upper bolt 30a and the lower bolt 30b.

[0056] The pressure-reducing connector 50 includes a first main hinge 51 engaged with an upper bolt 30a, a second main hinge 52 engaged with a lower bolt 30b, and a first connecting rod 53 fastened between the first main hinge 51 and the second main hinge 52. The first connecting rod 53 prevents the pressure applied to the battery cell 11 from increasing excessively due to the increased bending stiffness of the end plate 20 with the application of the reinforcing plate 40.

[0057] To perform this function, the first connecting rod 53 has a rod shape with a thickness smaller than that of the upper bolt 30a and lower bolt 30b constituting the fastening bolt 30. The upper bolt 30a and lower bolt 30b, as well as the first connecting rod 53, are all formed of metallic material. Even when a force in the vertical direction (parallel to the Z-axis) is applied to the end plate 20 due to expansion pressure, the relatively thick upper bolt 30a and lower bolt 30b hardly elongate. Conversely, when a larger force is applied to the end plate 20, the relatively thin first connecting rod 53 can elongate to reduce the pressure applied to the battery cell stack 10. When the pressure applied to the battery cell stack 10 is too high, the pores of the separator in the battery cell 11 may become blocked, thus potentially degrading the performance of the battery cell 11. The pressure-reducing connector 50 corresponds to an element used to prevent performance degradation of the battery cell 11.

[0058] The pressure-reducing connector 50 may also include at least a pair of first sub-connecting rod assemblies 54, which are disposed on one side and the other side of the first connecting rod 53 and hinged to the first main hinge 51 and the second main hinge 52.

[0059] The first sub-connecting rod assembly 54 includes a pair of first sub-connecting rods 54a and 54b respectively hinged to the first main hinge 51 and the second main hinge 52, and a first sub-hinge 54c hinged between the pair of first sub-connecting rods 54a and 54b.

[0060] Each of the pair of first sub-connecting rods 54a and 54b is formed of metal and has a thickness less than that of the upper bolt 30a and the lower bolt 30b. The sum of the lengths of the pair of first sub-connecting rods 54a and 54b is greater than the length of the first connecting rod 53. Therefore, as the first connecting rod 53 elongates due to the increase in expansion pressure, the first sub-hinge 54c extends along... Figure 6 The arrow in the diagram moves towards the first connecting rod 53. When the first sub-hinge 54c reaches a position where it can no longer move, tension is applied to the first sub-connecting rods 54a and 54b according to the expansion pressure. Therefore, the first sub-connecting rods 54a and 54b extend together with the first connecting rod 53, thereby reducing the expansion pressure.

[0061] The pressure-reducing connector 50 may further include at least one pair of second sub-connecting rod assemblies 55 disposed on one side and the other side of the first connecting rod 53, and located further outward than the first sub-connecting rod assembly 54. The pair of second sub-connecting rod assemblies 55 are hinged to the first main hinge 51 and the second main hinge 52.

[0062] The second sub-connecting rod assembly 55 includes a pair of second sub-connecting rods 55a and 55b respectively hinged to the first main hinge 51 and the second main hinge 52, and a second sub-hinge 55c hinged between the pair of second sub-connecting rods 55a and 55b.

[0063] Each of the pair of second sub-connecting rods 55a and 55b is formed of metal and has a thickness less than that of the upper bolt 30a and the lower bolt 30b. The sum of the lengths of the pair of second sub-connecting rods 55a and 55b is greater than the sum of the lengths of the pair of first sub-connecting rods 54a and 54b. Therefore, as the first sub-connecting rods 54a and 54b elongate due to the increase in expansion pressure, the second sub-hinge 55c extends along... Figure 6 The arrow moves in the direction of the first sub-connecting rod assembly 54. When the second sub-hinge 55c reaches the position where the second sub-hinge 55c can no longer move, tension is applied to the second sub-connecting rods 55a and 55b according to the expansion pressure. Therefore, the second sub-connecting rods 55a and 55b extend together with the first connecting rod 53 and the first sub-connecting rods 54a and 54b, thereby reducing the expansion pressure.

[0064] Although the accompanying drawings illustrate a battery module according to embodiments of the present disclosure including a first sub-connecting rod assembly 54 and a battery module including a first sub-connecting rod assembly 54 and a second sub-connecting rod assembly 55, the present disclosure is not limited thereto. That is, the battery module according to embodiments of the present disclosure may include additional sub-connecting rod assemblies besides the first sub-connecting rod assembly 54 and the second sub-connecting rod assembly 55.

[0065] A battery pack according to an embodiment of the present disclosure includes a battery module as described above according to an embodiment of the present disclosure. Furthermore, a vehicle according to an embodiment of the present disclosure includes a battery module as described above according to an embodiment of the present disclosure.

[0066] Although embodiments of the present disclosure have been shown and described above, the present disclosure is not limited to the specific embodiments described above. Various modified embodiments can be made by those skilled in the art without departing from the scope of the present disclosure as claimed in the claims.

Claims

1. A battery module, comprising: A battery cell stack, wherein the battery cell stack comprises multiple battery cells; A first end plate and a second end plate, the first end plate and the second end plate respectively covering the top and bottom surfaces of the battery cell stack; The first upper reinforcing plate and the second upper reinforcing plate are located on the first end plate and extend from one side and the other side of the first end plate toward the middle of the first end plate along the length direction of the first end plate, respectively. The first lower reinforcing plate and the second lower reinforcing plate are located on the second end plate and extend from one side and the other side of the second end plate toward the middle of the second end plate along the length direction of the second end plate, respectively. The first fastening bolt is located on one side of the battery cell stack along its length and passes through the first upper reinforcing plate, the first end plate, the second end plate, and the first lower reinforcing plate. as well as The second fastening bolt is located on the other side of the battery cell stack along its length and passes through the second upper reinforcing plate, the first end plate, the second end plate, and the second lower reinforcing plate. Each of the first fastening bolt and the second fastening bolt includes an upper bolt and a lower bolt spaced apart from each other. The battery module also includes a pressure-reducing connector that connects the upper bolt and the lower bolt.

2. The battery module according to claim 1, wherein, The first upper reinforcing plate and the second upper reinforcing plate extend toward each other but are spaced apart from each other, and The first lower reinforcing plate and the second lower reinforcing plate extend toward each other but are spaced apart from each other.

3. The battery module according to claim 1, wherein, A pair of first fastening bolts and a pair of second fastening bolts are respectively disposed at one end and the other end of the battery module along the width direction of the battery module.

4. The battery module according to claim 3, wherein, A pair of first upper reinforcing plates and a pair of first lower reinforcing plates are respectively disposed at one end and the other end of the battery module along the width direction of the battery module, and A pair of second upper reinforcing plates and a pair of second lower reinforcing plates are respectively disposed at one end and the other end of the battery module along the width direction of the battery module.

5. The battery module according to claim 3, wherein, The first upper reinforcing plate and the first lower reinforcing plate are respectively fastened to the first end plate and the second end plate by a pair of first fastening bolts, and The second upper reinforcing plate and the second lower reinforcing plate are fastened to the first end plate and the second end plate respectively by a pair of second fastening bolts.

6. The battery module according to claim 1, wherein, The pressure-reducing connector includes: The first main hinge is connected to the upper bolt; The second main hinge, which is coupled to the lower bolt; and A first connecting rod is fastened between the first main hinge and the second main hinge.

7. The battery module according to claim 6, wherein, The pressure-reducing connector further includes a pair of first sub-connecting rod assemblies, which are respectively disposed on one side and the other side of the first connecting rod and hinged to the first main hinge and the second main hinge.

8. The battery module according to claim 7, wherein, Each of the pair of first sub-connecting rod assemblies includes: A pair of first sub-connecting rods, the pair of first sub-connecting rods being respectively hinged to the first main hinge and the second main hinge; and The first sub-hinge is hinged between the pair of first sub-connecting rods.

9. The battery module according to claim 8, wherein, The sum of the lengths of the pair of first sub-connecting rods is greater than the length of the first connecting rod.

10. The battery module according to claim 9, wherein, The pressure-reducing connector further includes a pair of second sub-connecting rod assemblies, which are disposed on one side and the other side of the first connecting rod, are located further outward than the first sub-connecting rod assembly, and are hinged to the first main hinge and the second main hinge.

11. The battery module according to claim 10, wherein, Each of the pair of second sub-connecting rod assemblies includes: A pair of second sub-connecting rods, the pair of second sub-connecting rods being respectively hinged to the first main hinge and the second main hinge; and The second sub-hinge is hinged between the pair of second sub-connecting rods.

12. The battery module according to claim 11, wherein, The sum of the lengths of the pair of second sub-connecting rods is greater than the sum of the lengths of the pair of first sub-connecting rods.

13. A battery pack comprising a battery module according to any one of claims 1 to 12.

14. A vehicle comprising a battery module according to any one of claims 1 to 12.

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