Battery pack

Abstract

A battery pack. The battery pack comprises a housing, a plurality of battery modules, and fillers, wherein the housing comprises a plurality of side walls; one battery module comprises a plurality of battery cells arranged in a first direction; and the plurality of battery modules are arranged in a second direction. The fillers comprise first sub-portions and second sub-portions, wherein the first sub-portions are arranged between the battery modules and the side walls; each second sub-portion is arranged between two adjacent battery modules; and the elastic modulus of the fillers is less than the elastic modulus of the battery cells.

Description

Battery pack

[0001] This application claims priority to Chinese Patent Application No. 202423111667.7, filed on December 16, 2024, entitled "Battery Pack", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of battery technology, specifically to battery packs. Background Technology

[0003] With increasingly stringent requirements for battery pack assembly efficiency and energy density, battery pack assembly methods are gradually evolving from the original CTM (Cell to Module) technology to CTP (Cell to Pack) technology. CTM technology involves assembling battery cells into modules, which are then fixed to a casing or structural components to form a battery pack. CTP technology involves directly fixing battery cells to a casing using structural components to form a battery pack. Invention Overview

[0004] Battery packs using CTP technology suffer from insufficient safety and stability under conditions of vibration and impact. Related technologies use pressure strips added to the top of the cells, utilizing the pressure between the strips and the bottom wall of the pack to secure the cells. However, the connection between the pressure strips and the cells is rigid. When the battery pack is subjected to vibration or impact, the pressure from the pressure strips can cause increased stress at the internal weld points, leading to damage to the cells.

[0005] An embodiment of this application provides a battery pack, the battery pack comprising:

[0006] The box body includes multiple side walls, which together form an accommodating space;

[0007] Multiple battery modules are disposed within the accommodating space, one of the battery modules including multiple battery cells arranged along a first direction, and the multiple battery modules arranged along a second direction;

[0008] The filler includes a first sub-part and a second sub-part. The first sub-part is disposed between the battery module and the second sidewall, and the second sub-part is disposed between two adjacent battery modules. The elastic modulus of the filler is less than that of the battery cell. Beneficial effects

[0009] In the embodiments of this application, by providing fillers between battery modules arranged along the second direction, when the battery pack is subjected to vibration, impact, or other conditions, the fillers are more susceptible to deformation under stress than the cells because the elastic modulus of the fillers is less than that of the cells. This reduces the impact force on the cells and improves the technical problem of insufficient safety and stability of the battery pack under vibration, impact, and other conditions. Attached Figure Description

[0010] Figure 1 is a perspective view of the battery pack provided in an embodiment of this application;

[0011] Figure 2 is a schematic diagram of the disassembled structure of the battery pack in Figure 1;

[0012] Figure 3 is a top view of a partial structure of the battery pack in Figure 1;

[0013] Figure 4 is a schematic diagram of the cross-sectional structure of section BB in Figure 3;

[0014] Figure 5 is a schematic diagram of the cross-sectional structure of section CC in Figure 3;

[0015] Figure 6 is an enlarged structural diagram of the area marked by the dashed line in Figure 5. Embodiments of the present invention

[0016] In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in actual use or operation, specifically the orientation shown in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.

[0017] An embodiment of this application provides a battery pack 1, as shown in Figures 1 to 3. The battery pack 1 includes a housing 10, a plurality of battery modules 20, and a filler 30. The housing 10 includes a plurality of side walls, which together form an accommodating space. The plurality of battery modules 20 are disposed within the accommodating space. One battery module 20 includes a plurality of battery cells 21 arranged along a first direction D1, and the plurality of battery modules 20 are arranged along a second direction D2. The filler 30 includes a first sub-part 31 and a second sub-part 32. The first sub-part 31 is disposed between the battery module 20 and the second side wall 12, and the second sub-part 32 is disposed between two adjacent battery modules 20 along the second direction D2. The elastic modulus of the filler 30 is less than the elastic modulus of the battery cells 21.

[0018] The enclosure 10 includes multiple side walls, which are connected to form a receiving space. The shape of the enclosure 10 can be set as needed, and the number of side walls can also be set as needed.

[0019] In some embodiments, the housing 10 includes two first sidewalls 11 disposed opposite to each other along a first direction D1 and two second sidewalls 12 disposed opposite to each other along a second direction D2. The two ends of the first sidewalls 11 are respectively connected to a second sidewall 12, and the two ends of the second sidewalls 12 are respectively connected to a first sidewall 11. The multiple sidewalls are connected to form an accommodating space.

[0020] In some embodiments, the angle between the first direction D1 and the second direction D2 is an acute angle or a right angle. The accompanying drawings of this application illustrate the angle between the first direction D1 and the second direction D2 as a right angle, but this should not be construed as a limitation of this application.

[0021] It should be noted that the first sidewall 11 can be located inside the battery pack 1, that is, the first sidewall 11 and the sidewall of the battery pack 1 can be different sidewalls. As shown in Figure 2, a receiving space is formed between the first sidewall 11 and the sidewall of the battery pack 1, and this receiving space can be used to install the battery management system (BMS), etc.

[0022] The housing 10 also includes a bottom, and multiple side walls are provided around the edge of the bottom. The bottom and multiple side walls form a box-like structure, and the battery module 20 is disposed inside the housing 10.

[0023] It should be noted that the number of battery modules 20 can be set as needed. When the number of battery modules 20 is small, they can be arranged only along the second direction D2; when the number of battery modules 20 is large, they can be arranged simultaneously along the first direction D1 and the second direction D2. When the battery modules 20 are arranged simultaneously along the first direction D1 and the second direction D2, a middle beam can be provided between two adjacent battery modules 20 arranged along the first direction D1, and a middle beam can be provided between two adjacent battery modules 20 arranged along the second direction D2. The two middle beams in different directions intersect to form a cross shape. As shown in Figures 2 and 3, the figures show two middle beams in a cross shape. The middle beams are used to separate two adjacent battery modules 20 and increase the overall strength of the battery pack.

[0024] As shown in Figures 2 and 3, the battery module 20 includes a plurality of battery cells 21 arranged along the first direction D1. The battery cells 21 can be square cells 21 or cylindrical cells 21, and there is no limitation here.

[0025] In some embodiments, as shown in Figures 2 and 3, the battery cell 21 includes a housing and a cover plate. The housing is disposed in contact with the bottom of the casing, and the cover plate is located on the side of the housing away from the bottom of the casing. The housing can be made of metal, such as aluminum, but is not limited thereto.

[0026] In the embodiments of this application, as shown in Figures 2 and 3, the battery pack 1 adopts CTP technology. A filler 30 is provided between two adjacent battery modules 20, and the battery modules 20 are directly fixed to the housing 10 through the filler 30. The filler 30 is provided between two adjacent battery modules 20 along the second direction D2. The filler 30 and the second sidewall 12 achieve pre-tightening fixation of the battery modules 20, preventing the cells 21 from shaking and improving the safety and stability of the battery pack 1.

[0027] The elastic modulus of the filler 30 is lower than that of the battery cell 21. The casing of the battery cell 21 is typically made of metal, which is relatively rigid. The high elastic modulus of the battery cell 21 makes it prone to internal stress when subjected to external impact, potentially leading to casing damage. The lower elastic modulus of the filler 30 allows it to deform more easily under impact, acting as a buffer and reducing the impact on the battery cell 21, thus lowering the risk of damage. The elastic modulus refers to the ratio of stress to strain in a material under stress. Under the same stress, a higher elastic modulus makes a material less prone to deformation, while a lower elastic modulus makes it more susceptible to deformation.

[0028] The filler 30 can be made of adhesive materials, such as expanding foam, potting compound, etc., but is not limited to these. The material of the filler 30 can be selected according to the space to be filled.

[0029] As shown in Figures 2 and 3, the first sub-part 31 is disposed between the battery module 20 and the side wall, and the second sub-part 32 is disposed between two adjacent battery modules 20 along the second direction D2. The first sub-part 31 and the second sub-part 32 can bond and fix the multiple battery modules 20 inside the housing 10 to the second side wall 12. Through the above arrangement, the battery cell 21 and the housing 10 can be integrated into a whole, increasing the stability and reliability of the system.

[0030] The first sub-part 31 and the second sub-part 32 can be made of the same material, thus forming them using the same process, simplifying the manufacturing process of the battery pack 1.

[0031] As shown in Figures 2 and 3, the dimension of the first sub-part 31 in the first direction D1 is greater than or equal to the dimension of the battery module 20 in the first direction D1, so that the length of the first sub-part 31 in the first direction D1 covers the entire battery module 20 as much as possible.

[0032] In some embodiments, as shown in Figures 3 and 5, the filler 30 is disposed in contact with the battery cell 21, and the height h1 of the filler 30 is less than or equal to the height h2 of the battery cell 21.

[0033] In this application, height refers to the direction that is perpendicular to both the first direction D1 and the second direction D2, and the height direction is also the direction perpendicular to the bearing surface of the bottom of the box.

[0034] As shown in Figure 5, the lower surface of the filler 30 can be on the same horizontal plane as the lower surface of the battery cell 21, that is, the lower surface of the filler 30 can contact the bottom of the box, and the lower surface of the battery cell 21 can also contact the bottom of the box. The height h1 of the filler 30 is less than the height h2 of the battery cell 21, thereby preventing the filler 30 from overflowing onto the upper surface of the battery cell 21 and affecting the closing of the box body 10 and the box cover 50.

[0035] In some embodiments, the ratio of the height h1 of the filler 30 to the height h2 of the cell 21 is 10% to 90%. With the above setting, the height h1 of the filler 30 can be at least 10% lower than the height h2 of the cell 21, further reducing the risk of the filler 30 overflowing onto the upper surface of the cell 21.

[0036] In some embodiments, as shown in FIG5, the thickness s2 of the second sub-part 32 is less than or equal to the thickness s1 of the first sub-part 31. The thickness s2 of the second sub-part 32 refers to the dimension in the direction where the smallest dimension of the second sub-part 32 is located. As shown in FIG3 and FIG5, the thickness s2 of the second sub-part 32 is the dimension of the second sub-part 32 in the second direction D2, and the thickness s1 of the first sub-part 31 is the dimension of the first sub-part 31 in the second direction D2. By setting the thickness s1 of the second sub-part 32 to be less than or equal to the thickness s1 of the first sub-part 31, the spacing between two adjacent cell modules 21 in the second direction D2 can be reduced, increasing the energy density of the battery pack 1. The thickness s1 of the first sub-part 31 is greater than the thickness s2 of the second sub-part 32, which makes the fixation between the second sidewall 12 and the battery module 20 more secure.

[0037] In some embodiments, as shown in Figures 3 to 5, the battery module 20 includes a first structural member 22 disposed between two adjacent battery cells 21, wherein the elastic modulus of the first structural member 22 is less than the elastic modulus of the filler 30.

[0038] The first structural member 22 is disposed between two adjacent cells 21 along the first direction D1. On the one hand, the first structural member 22 can provide a preload force on the battery module 20 in the first direction D1. On the other hand, the elastic modulus of the first structural member 22 is less than that of the filler 30, and the first structural member 22 is more easily deformed under stress than the cell 21, thereby reducing the impact force on the cell 21 in the first direction D1, and further improving the technical problem of insufficient safety and stability of the battery pack 1 under vibration, impact and other working conditions.

[0039] The material of the first structural member 22 is different from that of the filler 30. For example, the first structural member 22 can be made of a cushioning material such as foam. The first structural member 22 is more easily deformable than the filler 30.

[0040] It should be noted that the battery cell 21 will expand after a certain period of use, and the expansion amount of the battery cell 21 can be different in different directions. For example, taking a square battery cell 21 as an example, the area of ​​two of the sidewalls of the square battery cell 21 is larger than the area of ​​the other two. For ease of description, the two larger surfaces of the sidewalls of the square battery cell 21 are called large end faces, and the two smaller surfaces are called small end faces. The battery cell 21 has a greater expansion amount in the direction perpendicular to the large end face. Therefore, a material with a lower elastic modulus can be placed between the large end faces of two adjacent battery cells 21 to absorb the deformation of the battery cell 21 caused by expansion during its lifespan, thereby improving the stress concentration problem caused by the expansion of the battery cell 21.

[0041] Referring to Figure 2, in this application, the large end face of the battery cell 21 is perpendicular to the first direction D1, and the small end face of the battery cell 21 is perpendicular to the second direction D2. The first structural member 22 is disposed between two adjacent battery cells 21 along the first direction D1. The elastic modulus of the first structural member 22 is less than the elastic modulus of the filler 30, thereby better absorbing the deformation caused by the expansion of the battery cell 21.

[0042] As shown in Figures 5 and 6, in order to avoid interference between two adjacent first structural members 22 along the second direction D2, the first structural member 22 can be made not to extend beyond the large end face of the cell 21.

[0043] In some embodiments, as shown in Figures 5 and 6, the first structural member 22 includes two first sub-members 221 arranged along the second direction D2. The two first sub-members 221 are respectively disposed corresponding to an edge region of the battery cell 21, and the dimension of the first sub-member 221 in the height direction of the battery pack 1 is greater than or equal to the height of the second sub-part 32 and less than or equal to the height h2 of the battery cell 21.

[0044] As shown in Figure 6, the two first sub-components 221 can be respectively positioned corresponding to the left and right edges of the large end face of the battery cell 21. The dimension of the first sub-component 221 in the height direction of the battery pack 1 is less than or equal to the height h2 of the battery cell 21, thereby preventing the first sub-component 221 from extending beyond the large end face of the battery cell 21 in the height direction of the battery pack 1. The dimension of the first sub-component 221 in the second direction D2 is less than the dimension of the battery cell 21 in the second direction D2, and adjacent first sub-components 221 are spaced apart, so that the first sub-component 221 does not extend beyond the large end face of the battery cell 21 in the second direction D2. Through the above arrangement, the orthographic projection of the first sub-component 221 on the large end face of the battery cell 21 can be located on the large end face of the battery cell 21, that is, the first sub-component 221 does not extend beyond the large end face of the battery cell 21.

[0045] Optionally, as shown in FIG6, in some embodiments, the first sub-component 221 has a dimension in the height direction of the battery pack 1 that is greater than or equal to the height of the second sub-component 32, so that the first sub-component 221 can block the filler 30 and prevent the filler 30 from overflowing from the left and right sides of the cell 21 into the large end face of two adjacent cells 21 during the potting process.

[0046] Furthermore, as shown in Figure 6, the end of the first sub-component 221 near the bottom of the casing is close to the bottom surface of the battery cell 21, thereby reducing the risk of the filler 30 overflowing from the gap between the first sub-component 221 and the bottom surface of the battery cell 21 into the large end face of the battery cell 21. For example, the distance between the lower end of the first sub-component 221 and the lower surface of the battery cell 21 can be smaller than the distance between the upper end of the first sub-component 221 and the upper surface of the battery cell 21.

[0047] In some embodiments, as shown in FIG6, the first structural member 22 includes two second sub-members 222 arranged along the height direction of the battery pack 1. The two second sub-members 222 are respectively disposed corresponding to an edge region of the battery cell 21, and the two ends of the second sub-members 222 abut against the first sub-members 221.

[0048] As shown in Figure 6, two second sub-components 222 are respectively disposed on the upper and lower edges of the large end face of the cell 21. In the second direction D2, the size of the second sub-component 222 is smaller than the size of the cell 21; in the height direction of the battery pack 1, the size of the second sub-component 222 is smaller than the height h2 of the cell 21, and the two second sub-components 222 are spaced apart in the height direction of the battery pack 1. The second sub-components 222 can prevent the filler 30 from overflowing from the upper and lower sides of the cell 21 to the large end face of the cell 21.

[0049] Optionally, both ends of the second sub-component 222 abut against the first sub-component 221. Specifically, the left end of the second sub-component 222 abuts against the first sub-component 221 located on the left edge, and the right end of the second sub-component 222 abuts against the first sub-component 221 located on the right edge. With the above arrangement, the first sub-component 221 and the second sub-component 222 can form an approximately closed frame structure, further reducing the risk of the filler 30 overflowing onto the large end face of the cell 21.

[0050] It should be noted that in the battery pack 1, both the first sub-component 221 and the second sub-component 222 are in a compressed state, and the thickness of the first sub-component 221 after compression is the same as the thickness of the second sub-component 222. Both the first sub-component 221 and the second sub-component 222 can be used to provide pre-tightening force to achieve pre-tightening fixation of the battery cell 21 in the first direction D1.

[0051] In some embodiments, the elastic modulus of the first sub-component 221 is greater than or equal to the elastic modulus of the second sub-component 222.

[0052] Optionally, both the first sub-component 221 and the second sub-component 222 are made of foam, but the foaming ratios of the first sub-component 221 and the second sub-component 222 are different, thus giving them different elastic moduli. The foaming ratio of the first sub-component 221 is less than that of the second sub-component 222. For example, the first sub-component 221 can be foam with a foaming ratio of 5, and the second sub-component 222 can be foam with a foaming ratio of 10 to 20.

[0053] In some embodiments, as shown in FIG4, the battery pack 1 includes an end plate 40, which is disposed on the surfaces of the battery module 20 at opposite ends along the first direction D1. A second structural member 41 is disposed between the end plate 40 and the battery module 20. The elastic modulus of the second structural member 41 is less than the elastic modulus of the filler 30.

[0054] The material of the second structural component 41 can be foam, and the foaming ratio of the foam can be set as needed. For example, the foam of the second structural component 41 can have the same foaming ratio as that of the first sub-component 221. The second structural component 41 can further realize the pre-tightening fixation of the battery cell 21 in the first direction D1.

[0055] End plates 40 are used to enhance structural stability, improve safety, and optimize thermal management. End plates 40 can be made of high-strength materials, such as metals or composite materials. These materials have good mechanical strength and impact resistance. When the battery module 20 is subjected to external impact or vibration, the end plates 40 can provide additional protection to prevent mutual squeezing or damage between the cells 21, thereby reducing safety risks such as short circuits and thermal runaway of the cells 21.

[0056] In some embodiments, as shown in Figures 1 and 2, the battery pack 1 includes a cover 50, which covers the housing 10, and a gap is provided between the cover 50 and the side surface of the battery module 20 near the cover 50.

[0057] The cover 50 closes to the side wall of the housing 10. Since the battery module 20 is pre-tightened and fixed by the filler 30 and the first structural member 22 in the first direction D1 and the second direction D2, the cover plate and the upper surface of the battery module 20 can be spaced apart; that is, the surface of the cover 50 near the housing 10 is spaced apart from the surface of the battery module 20 near the cover 50. This arrangement prevents the cover 50 from squeezing the battery cell 21 along the height direction of the battery pack 1, thus preventing damage to the battery cell 21.

Claims

1. A battery pack (1), comprising: The box (10) includes multiple side walls, which together form an accommodating space; Multiple battery modules (20) are disposed within the accommodating space. One of the battery modules (20) includes multiple battery cells (21) arranged along a first direction (D1), and the multiple battery modules (20) are arranged along a second direction (D2). The filler (30) includes a first sub-part (31) and a second sub-part (32). The first sub-part (31) is disposed between the battery module (20) and the side wall, and the second sub-part (32) is disposed between two adjacent battery modules (20). The elastic modulus of the filler (30) is less than that of the cell (21).

2. The battery pack (1) according to claim 1, wherein, The filler (30) is disposed in contact with the battery cell (21), and the height (h1) of the filler (30) is less than or equal to the height (h2) of the battery cell (21).

3. The battery pack (1) according to claim 2, wherein, The ratio of the height (h1) of the filler (30) to the height (h2) of the cell (21) is 10% to 90%.

4. The battery pack (1) according to claim 1, wherein, The thickness (s2) of the second sub-part (32) is less than or equal to the thickness (s1) of the first sub-part (31).

5. The battery pack (1) according to any one of claims 1 to 4, wherein, The battery module (20) includes a first structural member (22) disposed between two adjacent cells (21), the elastic modulus of the first structural member (22) being less than the elastic modulus of the filler (30).

6. The battery pack (1) according to claim 5, wherein, The first structural member (22) includes two first sub-members (221) arranged along the second direction (D2). The two first sub-members (221) are respectively disposed corresponding to an edge region of the cell (21), and the dimension of the first sub-member (221) in the height direction of the battery pack (1) is greater than or equal to the height of the second sub-part (32) and less than or equal to the height (h2) of the cell (21).

7. The battery pack (1) according to claim 6, wherein, The first structural member (22) includes two second sub-members (222) arranged along the height direction of the battery pack (1). The two second sub-members (222) are respectively disposed corresponding to an edge region of the battery cell (21), and the two ends of the second sub-members (222) abut against the first sub-member (221).

8. The battery pack (1) according to claim 7, wherein, The elastic modulus of the first sub-component (221) is greater than or equal to the elastic modulus of the second sub-component (222).

9. The battery pack (1) according to any one of claims 1 to 4 or any one of claims 6 to 8, comprising an end plate (40) disposed on the surfaces of the battery module (20) at opposite ends along the first direction (D1), wherein a second structural member (41) is disposed between the end plate (40) and the battery module (20), the elastic modulus of the second structural member (41) being less than the elastic modulus of the filler (30).

10. The battery pack (1) according to any one of claims 1 to 4 or any one of claims 6 to 8, comprising a cover (50) that covers the housing (10), and a gap is provided between the cover (50) and a side surface of the battery module (20) near the cover (50).

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