Battery pack

Abstract

The present application discloses a battery pack. The battery pack comprises a plurality of battery cells and a buffer member, wherein the plurality of battery cells are arranged spaced apart from one another; the buffer member is arranged between adjacent single batteries, and a buffer space comprises a plurality of interconnected basic units, wherein a side wall of each basic unit has N flat surfaces and N curved surfaces, the N flat surfaces and the N curved surfaces are connected edge-to-edge in an alternating manner, each basic unit is provided with a through-hole, and the curved surface curves toward the through-hole.

Description

A battery pack

[0001] This application claims priority to Chinese Patent Application No. 2024228097098, filed with the Chinese Patent Office on November 15, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of battery technology, and particularly to a battery pack. Background Technology

[0003] After the battery pack has been operating for a period of time, especially near the end of the life of a single cell, the single cell will swell significantly. Technical issues

[0004] This causes the material between individual cells to be compressed and deformed, and the width of the material between individual cells will exceed the width of the individual cells. This will cause the steel strip on the battery module to be stressed, and the deformation of the steel strip will change the contact area between the steel strip and the individual cells. This will affect the tightness of the steel strip binding the individual cells, which will affect the reliability and safety of the battery pack. Technical solutions

[0005] In a first aspect, this application provides a battery pack, which includes multiple individual cells and a buffer. The multiple individual cells are arranged at intervals between each other. The buffer is arranged between adjacent individual cells. The buffer includes multiple interconnected basic units. The sidewalls of the basic units have N planes and N curved surfaces. The N planes and N curved surfaces are alternately connected end to end. The basic units have through holes, and the curved surfaces are bent toward the through holes. Beneficial effects

[0006] The beneficial effects provided by this application are as follows: The sidewall of the basic unit has N planes and N curved surfaces, which are alternately connected end-to-end to form a closed loop, with the curved surfaces curving towards the through-hole. The portion of the basic unit located on the curved surface forms a concave structure, while the portion located on the plane forms a flat structure. During use, the plane can abut against the individual battery cell. As the individual battery cell deforms, it exerts a force on the plane. The plane ensures a sufficiently large contact area with the individual battery cell, thereby reducing the local pressure exerted by the individual battery cell on the basic unit. The plane will continue to transfer the pressure to the curved surface, causing the curved surface to gradually close under pressure. This occupies the space formed by the concave curvature of the curved surface, thus transferring the deformation space of the buffer to the space occupied by the curved surface of the basic unit. This achieves a zero Poisson's ratio or a negative Poisson's ratio for the basic unit, thereby ensuring that the width of the buffer does not exceed the width of the individual battery cell, reducing the squeezing effect on the buffer straps, ensuring that the tightness of the steel strap binding the individual battery cell is not affected, and thus ensuring the reliability and safety of the battery pack.

[0007] The basic unit has through holes. After the basic unit is deformed by force, some of the material of the basic unit will move into the through holes until the through holes are filled, thereby occupying the space of the through holes to achieve zero Poisson's ratio or negative Poisson's ratio of the basic unit. In this way, the deformation space of the buffer will be transferred to the space occupied by the through holes of the basic unit, thereby keeping the width of the buffer from exceeding the width of the single cell, reducing the squeezing effect on the buffer straps, ensuring that the tightness of the steel strip binding the single cell is not affected, and thus ensuring the reliability and safety of the steel strip for the battery pack. Attached Figure Description

[0008] Figure 1 is a schematic diagram of the battery pack provided in an embodiment of this application;

[0009] Figure 2 is a schematic diagram of the structure of the basic element provided in the embodiment of this application;

[0010] Figure 3 is a schematic diagram of a structure of an embodiment of the buffer provided in this application;

[0011] Figure 4 is a structural schematic diagram of another embodiment of the buffer provided in this application;

[0012] Figure 5 is a schematic diagram of another embodiment of the buffer provided in this application.

[0013] Explanation of reference numerals in the attached figures:

[0014] 200 individual cells, 100 buffer components, 10 basic cells, 12 flat surfaces, 14 curved surfaces, and 16 through holes.

[0015] 18 splicing holes, 300 stress sensor.

[0016] Implementation methods of this application

[0017] Referring to Figures 1 to 3, Figure 1 is a structural schematic diagram of the battery pack provided in an embodiment of this application, Figure 2 is a structural schematic diagram of the basic element 10 provided in an embodiment of this application, and Figure 3 is a structural schematic diagram of an embodiment of the buffer 100 provided in an embodiment of this application.

[0018] This application provides a battery pack, comprising: a plurality of individual cells 200 and a buffer member 100. The plurality of individual cells 200 are spaced apart from each other, and the buffer member 100 is disposed between adjacent individual cells 200. The buffer member 100 includes a plurality of basic elements 10. The plurality of basic elements 10 can be disposed in the thickness direction of the individual cells 200, that is, the plurality of basic elements 10 can be disposed on the largest side of the individual cells 200, where the individual cells 200 are most likely to deform and the amount of deformation is also the largest, thus providing a good buffering effect. The plurality of basic elements 10 can also be disposed in the width direction of the individual cells 200, that is, the plurality of basic elements 10 can be disposed on the smallest side of the individual cells 200.

[0019] The sidewall of the basic element 10 has N planes 12 and N curved surfaces 14, which are connected end to end to form a closed loop. The curved surfaces 14 are curved toward the through hole 16. The portion of the basic element 10 located on the curved surface 14 forms a concave structure, while the portion of the basic element 10 located on the plane 12 forms a flat structure.

[0020] During use, the plane 12 can abut against the individual cell 200. As the individual cell 200 deforms, it exerts a force on the plane 12. The plane 12 ensures a sufficiently large contact area with the individual cell 200, thereby reducing the local pressure exerted by the individual cell 200 on the cell 10. The plane 12 then transmits the pressure to the curved surface 14, which gradually closes under pressure. This occupies the space formed by the concave shape of the curved surface 14, transferring the deformation space of the buffer 100 to the space occupied by the curved surface 14 of the cell 10. This achieves a zero or negative Poisson's ratio for the cell 10, ensuring that the width of the buffer 100 does not exceed the width of the individual cell 200. This reduces the squeezing effect on the buffer 100 straps, ensuring that the tightness of the steel strap binding the individual cell 200 is not affected, thus ensuring the reliability and safety of the battery pack.

[0021] The basic unit 10 has a through hole 16. The through hole 16 can be located in the middle or approximately in the middle of the basic unit 10, so that the basic unit 10 near the through hole 16 experiences more balanced force, resulting in more balanced deformation. The through hole 16 can also be located at an off-center position of the basic unit 10. After the basic unit 10 deforms under force, some of the material of the basic unit 10 will move towards the through hole 16 until it fills the through hole 16, thereby occupying the space of the through hole 16 to achieve a zero Poisson's ratio or a negative Poisson's ratio for the basic unit 10. In this way, the deformation space of the buffer 100 is transferred to the space occupied by the through hole 16 of the basic unit 10, thereby keeping the width of the buffer 100 from exceeding the width of the single cell 200, reducing the squeezing effect on the strap of the buffer 100, ensuring that the tightness of the steel strap binding the single cell 200 is not affected, and thus ensuring the reliability and safety of the steel strap for the battery pack.

[0022] In one embodiment, N is a multiple of 2, and N can be 2, 4, 6, 8, 10, etc. The basic element 10 is a centrally symmetrical shape. The advantage of this arrangement is that when the basic element 10 is placed between the individual battery cells 200, the basic element 10 can be subjected to symmetrical force, thereby distributing the pressure evenly across the basic element 10 and preventing irreversible deformation due to excessive local pressure. For example, when N equals 2, the outer contour of the basic element 10 forms a near-square quadrilateral; when N equals 4, the outer contour of the basic element 10 forms a near-square octagon; and when N equals 6, the outer contour of the basic element 10 forms a near-square dodecagon.

[0023] The length of plane 12 and the straight line length of surface 14 can be equal. In this way, the closed loop formed by the alternating connection of N planes 12 and N surfaces 14 is a quasi-regular polygon.

[0024] Optionally, the curved surface 14 can be arc-shaped, and the curvature of the curved surface 14 can be 1 / 4 circle, 1 / 2 circle, 1 / 4 circle, 1 / 2 circle, etc. The arc-shaped curved surface 14 has a smooth transition, and during the deformation process of the basic element 10, the resisting force experienced by the basic element 10 at the curved surface 14 is minimal, thus making deformation more favorable. In addition, the arc-shaped curved surface 14 has its own elasticity to recover deformation. After the external force is removed, the curved surface 14 can rely on its own elasticity to return to its original shape, thus it can be reused, improving the utilization efficiency of the basic element 10.

[0025] In one embodiment, the height of the base element 10 is H in the thickness direction of the single cell 200, and the height direction of the base element 10 is the thickness direction of the single cell 200, with a range of 0.5 mm ≤ H ≤ 20 mm. H can be 0.5 mm, 2 mm, 4 mm, 5 mm, 8 mm, 10 mm, 12 mm, 16 mm, 18 mm, 20 mm, etc. Within this range, the base element 10 can play a buffering role without excessively occupying the installation space of the single cell 200. When the base element 10 is larger than this value, the buffering effect of the base element 10 is not significantly improved, but it will excessively occupy the installation space of the single cell 200. When the base element 10 is smaller than this value, the buffering effect of the base element 10 will be greatly weakened, and it will be unable to play a role in transitioning and reducing the compression of the bandage by the single cell 200.

[0026] Optionally, the diameter of the through hole 16 is R, where R ≤ 0.25H, and R can be 0.25H, 0.2H, 0.15H, 0.1H, etc. As the size of the basic element 10 increases, the diameter of the through hole 16 also increases accordingly. Within the above range, the through hole 16 will not damage the overall structural strength of the basic element 10, so that when the basic element 10 is subjected to external force, the basic element 10 can slowly deform until the limit state, and after the external force disappears, the basic element 10 can still return to its original shape.

[0027] Optionally, the planes 12 of adjacent primitives 10 abut against each other, and the curved surfaces 14 of adjacent primitives 10 join together to form a splicing hole 18. The planes 12 are flat, so when subjected to force, the force can be smoothly transmitted to the contacting planes. In addition, the contact between the planes 12 can ensure the stability of the arrangement of the primitives 10 and prevent the primitives 10 from loosening during the process of being subjected to force.

[0028] Optionally, this embodiment protects the arrangement shown in FIG3. The interconnected basic units 10 are connected to each other through planes 12. The planes 12 located at opposite ends of the buffer member 100 are configured to abut against the individual battery 200, and the curved surface 14 faces the individual battery 200. In this embodiment, the buffer member 100 has at least two parts, referred to as the first part and the second part, respectively. The first part is provided on opposite sides of the second part. The first part and the second part form a sandwich structure. The first part is configured to abut against the individual battery 200. Multiple basic units 10 of the first part are arranged at intervals. The planes 12 of the basic units 10 of the first part are configured to abut against the individual battery 200. The planes 12 of the basic units 10 of the second part abut against each other and are connected to form a whole. At the same time, the planes 12 of the basic units 10 of the second part are also connected to the planes 12 of the basic units 10 of the first part, so that the first part and the second part are connected to form a whole.

[0029] In this embodiment, the buffer 100 is divided into multiple parts, which are connected to each other through their respective planes 12 to form a complete whole. When the buffer 100 is subjected to force, the basic elements 10 transmit the force to each other through the planes 12. The planes 12 can increase the contact area relative to the curved surface 14, thereby improving the stability of the overall structure and preventing the buffer 100 from loosening during use.

[0030] Referring to Figures 1, 4 and 5, Figure 4 is a structural schematic diagram of another embodiment of the buffer 100 provided in this application, and Figure 5 is a structural schematic diagram of another embodiment of the buffer 100 provided in this application.

[0031] In one embodiment, the battery pack further includes a stress sensor 300, which is disposed within the buffer 100. The stress sensor 300 can be a piezoelectric sensor, an electrostatic sensor, or a capacitive sensor. During the deformation process of the element 10, stress is synchronously applied to the stress sensor 300. Even without deformation, the stress sensor 300 senses stress and collects a mechanical signal. The manager in the battery pack can acquire this mechanical signal, thereby enabling more accurate management decisions.

[0032] Furthermore, the stress sensor 300 is housed within the buffer 100, with the element 10 encasing it. This prevents the stress sensor 300 from directly contacting the individual battery cell 200 to acquire pressure data, thus avoiding damage to the cell. In contrast, related solutions that attach the stress sensor 300 to the surface of the individual battery cell 200 alter the original mechanical boundaries of the battery module. Under prolonged pressure, the stress sensor 300 may puncture the blue film covering the cell cell 200, affecting electrical safety.

[0033] Optionally, the stress sensor 300 can be disposed in the through hole 16, which is a closed environment and thus protects the stress sensor 300. Alternatively, adjacent elements 10 can form a splicing hole 18, in which the stress sensor 300 can also be disposed, and the splicing hole 18 can also protect the stress sensor 300.

[0034] Optionally, there are multiple stress sensors 300, with each pair of stress sensors 300 forming a group. Each group of stress sensors 300 is symmetrically arranged along the thickness direction perpendicular to the single cell 200. Each stress sensor 300 can acquire a mechanical signal. By grouping two stress sensors 300 together, the signal strength at a certain location is multiplied, thereby achieving the purpose of locally strengthening the signal.

Claims

1. A battery pack, comprising: Multiple individual battery cells are arranged at intervals between them; A buffer element is disposed between adjacent individual cells. The buffer space includes multiple interconnected basic units. The sidewalls of the basic units have N planes and N curved surfaces, which are alternately connected end to end. The basic units have through holes, and the curved surfaces are bent toward the through holes.

2. The moiety according to claim 1, wherein, The planes of adjacent basic elements abut against each other, and the curved surfaces of adjacent basic elements abut against each other to form a splicing hole.

3. The moiety of claim 1, wherein, The surface is an arc shape.

4. The basis element of claim 3, wherein, The curvature of the surface is 1 / 4 circle or 1 / 2 circle.

5. The moiety of claim 1, wherein, N is a multiple of 2, and the primitive is a centrally symmetric figure.

6. The basis element of claim 5, wherein, N can be 2, 4, 6, 8, or 10.

7. The zyme of any one of claims 1 to 6, wherein, In the thickness direction of the single cell, the height of the cell is H, where 0.5 mm ≤ H ≤ 20 mm.

8. The moiety of claim 7, wherein, 5 mm ≤ H ≤ 10 mm.

9. The basemodule of claim 7, wherein, The diameter of the through hole is R, where R ≤ 0.25H.

10. The battery pack of claim 5, wherein, The curved surfaces located at opposite ends of the buffer member face the individual battery cell.

11. The battery pack of claim 1, wherein, The battery pack also includes a stress sensor disposed in the buffer.

12. The battery pack of claim 11, wherein, The stress sensor is a piezoelectric sensor, an electrostatic sensor, or a capacitive sensor.

13. The battery pack of claim 11, wherein, The stress sensor is disposed in the through hole.

14. The battery pack of claim 11, wherein, The curved surfaces of adjacent basic elements are joined to form a splicing hole, and the stress sensor is disposed in the splicing hole.

15. The battery pack of claim 11, wherein, The stress sensor is a plurality of them, and each pair of stress sensors is arranged in a group. Each group of stress sensors is symmetrically arranged along the thickness direction perpendicular to the individual battery cell.

16. The basemodule of claim 1, wherein, Multiple of the aforementioned basic elements are disposed on the side surface of the single cell in the thickness direction.

17. The basemodule of claim 1, wherein, The through hole is located at the middle position of the basic element.

18. The basemodule of claim 1, wherein, The length of the plane is equal to the length of the straight line of the curved surface.

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