Battery monomer and battery pack

Abstract

The utility model relates to the technical field of batteries, and discloses a single battery and a battery pack, the single battery comprises a shell, a first weak part and a second weak part, and the shell comprises a first wall with thickness; the first weak part and the second weak part are both arranged on the first wall, and the first weak part is arranged in a closed track to define an anti-explosion area; the second weak part and the first weak part are arranged at an interval, and the orthographic projection of the second weak part on the first wall in the first direction falls into the explosion-proof area; the first weak part and the second weak part are configured to be that when the internal pressure of the shell reaches a preset threshold value, at least one of the first weak part and the second weak part is damaged. The first weak part and the second weak part form an integrated pressure relief structure in the shell, so that an anti-explosion valve is prevented from being additionally mounted on the shell, and the problem that the performance of the battery monomer is damaged due to the fact that the anti-explosion valve is welded with the shell and a welding seam is easy to lose efficacy is solved. And the safety risk caused by the fact that a single weak part cannot be effectively opened can be avoided.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a battery cell and battery pack. Background Technology

[0002] With the development of lithium battery technology, the safety and reliability of individual battery cells are receiving increasing attention from users. The upright bottom-mounted battery cell separates the explosion-proof valve from the conductive end. The explosion-proof valve is located at the bottom of the battery cell casing, physically separating it from the conductive end. This allows high-temperature gases and ejected debris to move away from the conductive end in the event of thermal runaway, achieving thermoelectric separation. Currently, explosion-proof holes are typically opened at the bottom of the battery cell casing, and then the explosion-proof valve is welded to the casing, with the valve cover sealing the explosion-proof hole. However, the weld between the explosion-proof valve and the casing is prone to failure, leading to performance degradation of the battery cell. Utility Model Content

[0003] The purpose of this invention is to provide a battery cell and battery pack to solve the problem in the prior art where the weld between the explosion-proof valve and the casing is prone to failure, leading to damage to the performance of the battery cell.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] One aspect of this utility model is to provide a battery cell, comprising:

[0006] The housing includes a first wall disposed along a first direction;

[0007] The first weak point is located on the first wall. The structural strength of the first weak point is less than that of the first wall. The first weak point is arranged in a closed trajectory to enclose and form an explosion-proof area.

[0008] The second weak part is provided on the first wall. The structural strength of the second weak part is less than that of the first wall. The second weak part is spaced apart from the first weak part. The projection of the second weak part onto the first wall in the first direction falls into the explosion-proof area.

[0009] The first weak part and the second weak part are configured such that when the internal pressure of the housing reaches a preset threshold, at least one of the first weak part and the second weak part is destroyed to release the internal pressure of the housing.

[0010] In some embodiments, the first wall has a first surface and a second surface disposed opposite to each other, the first surface being disposed toward the outside of the housing along the first direction, and the second surface being disposed toward the inside of the housing along the first direction;

[0011] One of the first weak part and the second weak part is disposed on the first surface, and the other is disposed on the second surface.

[0012] In some embodiments, the first weak part is a groove, and / or the second weak part is a groove.

[0013] In some embodiments, the groove extends along a closed trajectory, the groove includes a groove bottom wall, and a notch is provided on the groove bottom wall and extends along the extending direction of the groove. Along the first direction, the depression size of the notch is H1, and the depression size of the groove is H2, and H1 and H2 satisfy: H1 < H2.

[0014] In some embodiments, the battery cell further includes a first connecting part, the first connecting part is disposed in the first weak part, and the first connecting part connects the first wall and the first weak part.

[0015] In some embodiments, along the first direction, the orthographic projection of the second weak part on the first wall and the orthographic projection of the first connecting part on the first wall at least partially overlap.

[0016] In some embodiments, the first wall further has a second direction perpendicular to the first direction; the battery cell further includes a second connecting part, the second connecting part is disposed in the second weak part, the second connecting part connects the first wall and the second weak part, and the second connecting part and the first connecting part are located on the same side of the center of the explosion-proof area in the second direction.

[0017] In some embodiments, the battery cell further includes a bottom support plate, the bottom support plate is disposed in the housing, the bottom support plate is spaced apart from the first wall, a gap between the bottom support plate and the first wall forms an exhaust space, and the bottom support plate is provided with a plurality of ventilation holes communicating with the exhaust space.

[0018] In some embodiments, the orthographic projection of the first weak part on the bottom support plate along the first direction of the first wall at least partially falls within the distribution area of the plurality of ventilation holes, and / or the orthographic projection of the second weak part on the bottom support plate along the first direction of the first wall at least partially falls within the distribution area of the plurality of ventilation holes.

[0019] In some embodiments, the battery cell further includes a support member, the support member is connected between the bottom support plate and the first wall, a plurality of support members are provided, and the plurality of support members at least surround the explosion-proof area.

[0020] In some embodiments, the battery cell further includes a first positioning member and a second positioning member, one of which is disposed on the base plate and the other is disposed on the support member, and the first positioning member and the second positioning member are connected in cooperation.

[0021] Another aspect of this invention is to provide a battery pack comprising the battery cells as described above.

[0022] Compared with the prior art, the advantages of this utility model embodiment of a battery cell and battery pack are as follows:

[0023] In this embodiment of the battery cell, a first weak point and a second weak point are provided on the first wall of the casing. The first weak point encloses an explosion-proof area, and the second weak point, along a first direction of the first wall, falls into the explosion-proof area via its projection onto the first wall. When the internal pressure of the casing reaches a preset threshold, at least one of the first and second weak points is destroyed, releasing the internal pressure of the casing. The first and second weak points form an integrated pressure relief structure in the casing, avoiding the need for an additional explosion-proof valve. This avoids the problem of welding the explosion-proof valve to the casing, where weld failure can easily damage the battery cell's performance. Furthermore, the first and second weak points provided in this application prevent a single weak point from failing to open effectively during thermal runaway of the battery cell, thus improving the safety and reliability of the battery cell. Attached Figure Description

[0024] Figure 1 This is a three-dimensional schematic diagram of a battery cell according to an embodiment of this utility model;

[0025] Figure 2 This is a top view schematic diagram of a battery cell according to an embodiment of this utility model;

[0026] Figure 3 yes Figure 2 Sectional view along line AA;

[0027] Figure 4 yes Figure 3 An enlarged diagram of 'a' in the diagram;

[0028] Figure 5 yes Figure 2 Sectional view along the BB direction;

[0029] Figure 6 This is a partial view of the housing from a bottom angle in one embodiment of the present invention;

[0030] Figure 7 This is a top view of a partial view of the housing in one embodiment of the present invention;

[0031] Figure 8 This is a partial cross-sectional view of the shell in one embodiment of the present invention;

[0032] Figure 9 This is a cross-sectional view of a battery cell according to another embodiment of the present invention;

[0033] Figure 10 yes Figure 9 Enlarged diagram of b in the middle;

[0034] Figure 11 This is a partial view of the housing from a bottom angle in another embodiment of the present invention;

[0035] Figure 12 This is a top view of a partial view of the housing in another embodiment of the present invention;

[0036] Figure 13 This is a cross-sectional view of the housing in another embodiment of the present invention;

[0037] Figure 14 yes Figure 13 A magnified diagram of 'c' in the diagram;

[0038] Figure 15 This is an exploded view of the bottom support plate and support component in this utility model.

[0039] Numbering on the map:

[0040] 10. Shell, 11. First wall, 111. First surface, 112. Second surface, 12. Second wall, 20. First weak part, 201. Explosion-proof area, 21. Groove, 211. Groove bottom wall, 22. Score, 30. Second weak part, 40. First connecting part, 50. Second connecting part, 60. Bottom plate, 601. Exhaust space, 61. Vent hole, 611. Distribution area, 62. First positioning element, 70. Support element, 71. Second positioning element, 80. Battery cell, Z, First direction, X, Second direction. Detailed Implementation

[0041] In the description of this utility model, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0042] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0043] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.

[0044] See Figures 1-5 As shown, this utility model embodiment provides a battery cell, including a housing 10, a first weak portion 20, and a second weak portion 30. The housing 10 includes a first wall 11 having mutually perpendicular first directions Z and second directions X. The first direction Z refers to the thickness direction of the first wall 11, and the second direction X refers to the direction perpendicular to the first direction Z in the plane of the first wall 11. The first weak portion 20 and the second weak portion 30 are both disposed on the first wall 11. The structural strength of the first weak portion 20 is less than the structural strength of the first wall 11. The first weak portion 20 is arranged in a closed trajectory to enclose and form an explosion-proof area 201. The structural strength of the second weak portion 30 is less than the structural strength of the first wall 11. The second weak portion 30 is spaced apart from the first weak portion 20. The projection of the second weak portion 30 along the first direction Z of the first wall 11 falls into the explosion-proof area 201. The first weak portion 20 and the second weak portion 30 are configured such that when the internal pressure of the housing 10 reaches a preset threshold, at least one of the first weak portion 20 and the second weak portion 30 is destroyed to release the internal pressure of the housing 10.

[0045] By forming an integrated pressure relief structure on the housing 10 through the first weak point 20 and the second weak point 30, the need for additional explosion-proof valves on the housing 10 is avoided. This prevents the explosion-proof valve from being welded to the housing 10, as weld failure can easily lead to performance degradation of the battery cells. Furthermore, the inclusion of the first weak point 20 and the second weak point 30 in this application prevents a single weak point from failing to open effectively during thermal runaway of the battery cell, thus improving the safety and reliability of the battery cell. Moreover, when thermal runaway occurs in the battery cell, both the first weak point 20 and the second weak point 30 are located on the first wall 11, which can guide the high-pressure gas to be rapidly discharged in a predetermined single direction, preventing the high-pressure gas from spreading irregularly from multiple directions on the housing 10.

[0046] See Figure 3As shown, the housing 10 has a receiving cavity, and the housing 10 also includes a second wall 12, which is spaced apart from the first wall 11 along a first direction Z. The receiving cavity is located between the first wall 11 and the second wall 12. The battery cell also includes a battery cell 80, which is disposed within the receiving cavity. In some embodiments, the second wall 12 is a cover plate. The battery cell 80 has tabs that are connected to the cover plate.

[0047] See Figures 4-8 As shown, the first wall 11 has a first surface 111 and a second surface 112 disposed opposite to each other. The first surface 111 is disposed towards the outside of the housing 10 along the first direction Z, and the second surface 112 is disposed towards the inside of the housing 10 along the first direction Z, that is, the second surface 112 is disposed towards the battery cell 80. One of the first weak part 20 and the second weak part 30 is disposed on the first surface 111; the other of the first weak part 20 and the second weak part 30 is disposed on the second surface 112, such that the first weak part 20 and the second weak part 30 are disposed on different surfaces of the first wall 11. This design avoids the internal pressure from concentrating on a single surface during thermal runaway, preventing unintended tearing, warping, or other deformations in the first wall 11. Furthermore, since the strength of the first weak point 20 and the second weak point 30 is lower than other parts of the shell 10, distributing them on both sides of the first wall 11 ensures that the weak points are distributed on both sides, resulting in a more balanced stress distribution on the first wall 11. This prevents a significant decrease in the structural strength of a single surface, which could lead to dents or damage during everyday pressure or impacts. In other embodiments, the first weak point 20 and the second weak point 30 can also be located on the same surface of the first wall 11; for example, both the first weak point 20 and the second weak point 30 can be located on the first surface 111 or both on the second surface 112.

[0048] See Figures 4-8As shown, in some embodiments, the first weak part 20 is a groove 21. The groove 21 extends along a closed trajectory. The depth direction of the groove 21 is the first direction Z of the first wall 11. By weakening the local thickness of the first wall 11, the first weak part 20 is formed, so that the structural strength of the first weak part 20 is lower than other positions of the first wall 11. Preferably, the first weak part 20 is an annular groove 21. The inner space of the ring formed by enclosing the first weak part 20 is an explosion-proof area 201. The groove 21 includes a groove bottom wall 211, and the groove bottom wall 211 is provided with a notch 22. The notch 22 extends along the extension direction of the groove 21. Along the first direction Z, the depression size of the notch 22 is H1, and the depression size of the groove 21 is H2. H1 and H2 satisfy: H1 < H2. The notch 22 forms a stress concentration point in the first weak part 20. When the first wall 11 bears an external force, the stress will preferentially accumulate at the notch 22, causing the crack to extend along the direction of the notch 22 instead of spreading randomly. Moreover, by setting the notch 22, the external force magnitude at which the first weak part 20 is damaged can be significantly reduced. The shape of the notch 22 is similar to the shape of the first weak part 20, and can be a runway shape, an oval shape, a circular shape, etc. There is one or more notch 22. The multiple notch 22 are arranged at intervals along the groove width direction of the groove 21.

[0049] Referring to Figure 6 , Figure 7 , Figure 11 and Figure 12 As shown, in order to improve the performance of the first wall 11 in resisting daily impacts, in some embodiments, the battery cell further includes a first connecting part 40. The first connecting part 40 is arranged in the first weak part 20, and the first connecting part 40 connects the first wall 11 and the first weak part 20. This can not only resist the daily impacts received by the battery cell, but also avoid the first weak part 20 flying out and causing harm when the first weak part 20 is damaged. When the first weak part 20 is a groove 21, the first connecting part 40 is arranged in the groove 21. One side of the first connecting part 40 facing the groove opening of the groove 21 is located in the groove 21, or one side of the first connecting part 40 facing the groove opening of the groove 21 is coplanar with the first surface 111 or the second surface 112 of the first wall 11 where the groove 21 is located.

[0050] Referring to Figure 11 and Figure 12 As shown, in some embodiments, the positive projection of the second weak part 30 in the first direction Z of the first wall 11 and the positive projection of the first connecting part 40 in the first direction Z of the first wall 11 at least partially overlap. With this setting, the strength at the position of the first connecting part 40 can be weakened through the second weak part 30, avoiding that the first weak part 20 cannot be damaged when the battery cell undergoes thermal runaway.

[0051] Referring to Figure 6 , Figure 7 , Figure 11 and Figure 12 As shown, in some embodiments, the second weak portion 30 is a groove 21. A notch 22 is provided within the groove 21, extending along the extension direction of the groove 21. Along the first direction Z, the recess size H1 of the notch 22 is smaller than the recess size H2 of the groove 21. The notch 22 forms a stress concentration point in the second weak portion 30. When the first wall 11 is subjected to external force, the stress preferentially accumulates at the notch 22, causing the crack to extend along the direction of the notch 22 rather than spreading randomly. Furthermore, by providing the notch 22, the magnitude of the external force causing damage to the second weak portion 30 can be significantly reduced.

[0052] See Figure 6 and Figure 8 As shown, in some embodiments, the battery cell further includes a second connecting portion 50, which is disposed within the second weak portion 30. The second connecting portion 50 connects the first wall 11 and the second weak portion 30. The second connecting portion 50 and the first connecting portion 40 are located on the same side of the center of the explosion-proof area 201 in the second direction X, to avoid the first weak portion 20 and the second weak portion 30 having opposite explosion tendencies, thus preventing them from being opened smoothly. By providing the second connecting portion 50, it is possible to prevent the second weak portion 30 from being damaged and splashing out.

[0053] See Figures 6-8 As shown, in some embodiments, both the first weak point 20 and the second weak point 30 are racetrack-shaped grooves. The first weak point 20 and the second weak point 30 are coaxially arranged. The first connecting part 40 and the second connecting part 50 are located on the same side of the center of the explosion-proof area 201 in the second direction X. The first weak point 20 is provided on the second surface 112, and the second weak point 30 is provided on the first surface 111. See reference. Figures 9-14 As shown, in some embodiments, the first weak portion 20 is provided on the first surface 111, and the second weak portion 30 is provided on the second surface 112. The first weak portion 20 is a circular groove, and the second weak portion 30 is a strip groove. Two first connecting portions 40 are provided at intervals within the first weak portion 20, and the two first connecting portions 40 are symmetrically arranged with respect to the circular center of the first weak portion 20. The first connecting portions 40 are arranged opposite to the strip groove, and the orthographic projections of the two first connecting portions 40 along the first direction Z of the first wall 11 both fall into the strip groove. The second connecting portion 50 may not be provided in the strip groove, thereby weakening the structural strength of the first wall 11 at the location of the first connecting portion 40.

[0054] See Figure 4 , Figure 5 and Figure 10As shown, in some embodiments, the battery cell further includes a base plate 60, which is disposed within the housing 10. The base plate 60 and the first wall 11 are spaced apart along a first direction Z. The gap between the base plate 60 and the first wall 11 forms an exhaust space 601. The base plate 60 has multiple vent holes 61 communicating with the exhaust space 601. The battery cell 80 is placed on the side of the base plate 60 away from the first wall 11, and the base plate 60 provides support for the battery cell 80. When the battery cell 80 experiences thermal runaway, high-temperature gas enters the exhaust space 601 through the vent holes 61 and is discharged to the positions of the first weak part 20 and the second weak part 30 through the exhaust space 601, thereby destroying the first weak part 20 and the second weak part 30 and facilitating gas release and pressure relief.

[0055] See Figure 4 , Figure 5 , Figure 10 and Figure 15 As shown, the orthographic projection of the first weak portion 20 along the first direction Z of the first wall 11 onto the base plate 60 at least partially falls within the distribution area 611 of the plurality of vent holes 61, and / or, the orthographic projection of the second weak portion 30 along the first direction Z of the first wall 11 onto the base plate 60 at least partially falls within the distribution area 611 of the plurality of vent holes 61. The distribution area 611 of the plurality of vent holes 61 refers to the total area occupied by the plurality of vent holes 61 on the base plate 60, within which the plurality of vent holes 61 are evenly distributed. This arrangement allows the high-temperature gas discharged through the vent holes 61 to directly reach the locations of the first weak portion 20 and the second weak portion 30, and after damaging the first weak portion 20 and the second weak portion 30, it can be smoothly discharged outside the housing 10.

[0056] See Figure 4 , Figure 5 , Figure 10 and Figure 15 As shown, the battery cell also includes a support member 70, which is connected between the base plate 60 and the first wall 11. Multiple support members 70 are provided, and they are arranged to surround at least the explosion-proof area 201. The support members 70 support the base plate 60, maintaining a gap between the base plate 60 and the first wall 11, ensuring the stability of the exhaust space 601 and facilitating the smooth discharge of high-temperature gases. The support member 70 is a gasket.

[0057] See Figure 15As shown, the battery cell also includes a first positioning member 62 and a second positioning member 71. One of the first positioning member 62 and the second positioning member 71 is disposed on the base plate 60, and the other of the first positioning member 62 and the second positioning member 71 is disposed on the support member 70. The first positioning member 62 and the second positioning member 71 are connected in cooperation. Through the cooperation of the first positioning member 62 and the second positioning member 71, the base plate 60 and the support member 70 are quickly positioned, facilitating the connection between the base plate 60 and the support member 70. The first positioning member 62 is one of a positioning post and a positioning hole, and the second positioning member 71 is the other of a positioning post and a positioning hole. The positioning post can be inserted and fixed in the positioning hole. In this embodiment, the first positioning member 62 is a positioning hole, which is opened in the base plate 60; the second positioning member 71 is a positioning post, which is fixed to the support member 70.

[0058] This utility model also provides a battery pack, including the battery cells as described above.

[0059] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present utility model, and these improvements and substitutions should also be considered within the protection scope of the present utility model.

Claims

1. A battery cell, characterized in that, include: The housing (10) includes a first wall (11) disposed along a first direction (Z); The first weak part (20) is provided on the first wall (11). The structural strength of the first weak part (20) is less than that of the first wall (11). The first weak part (20) is arranged in a closed trajectory to enclose and form an explosion-proof area (201). The second weak part (30) is provided on the first wall (11). The structural strength of the second weak part (30) is less than that of the first wall (11). The second weak part (30) is provided at intervals from the first weak part (20). The orthographic projection of the second weak part (30) along the first direction (Z) onto the first wall (11) falls into the explosion-proof area (201). The first weak part (20) and the second weak part (30) are configured such that when the internal pressure of the housing (10) reaches a preset threshold, at least one of the first weak part (20) and the second weak part (30) is destroyed to release the internal pressure of the housing (10).

2. The battery cell according to claim 1, characterized in that, The first wall (11) has a first surface (111) and a second surface (112) disposed opposite to each other. The first surface (111) is disposed towards the outside of the housing (10) along the first direction (Z), and the second surface (112) is disposed towards the inside of the housing (10) along the first direction (Z). One of the first weak part (20) and the second weak part (30) is located on the first surface (111), and the other is located on the second surface (112).

3. The battery cell according to claim 1 or 2, characterized in that, The first weak part (20) is a groove (21), and / or the second weak part (30) is a groove (21).

4. The battery cell according to claim 3, characterized in that, The groove (21) extends along a closed trajectory. The groove (21) includes a bottom wall (211) with a groove groove (22) extending along the extension direction of the groove (21). Along the first direction (Z), the recess size of the groove (22) is H1, and the recess size of the groove (21) is H2. H1 and H2 satisfy: H1 <H2。 5. The battery cell according to claim 1, characterized in that, The battery cell also includes a first connecting part (40), which is disposed in the first weak part (20) and connects the first wall (11) and the first weak part (20).

6. The battery cell according to claim 5, characterized in that, Along the first direction (Z), the orthographic projection of the second weak portion (30) onto the first wall (11) at least partially overlaps with the orthographic projection of the first connecting portion (40) onto the first wall (11).

7. The battery cell according to claim 5, characterized in that, The first wall (11) also has a second direction (X) perpendicular to the first direction (Z); the battery cell also includes a second connecting part (50), the second connecting part (50) is disposed in the second weak part (30), the second connecting part (50) connects the first wall (11) and the second weak part (30), and the second connecting part (50) and the first connecting part (40) are located on the same side of the center of the explosion-proof area (201) in the second direction (X).

8. The battery cell according to claim 1, characterized in that, The battery cell also includes a bottom support plate (60), which is disposed inside the housing (10). The bottom support plate (60) is spaced apart from the first wall (11). The gap between the bottom support plate (60) and the first wall (11) forms an exhaust space (601). The bottom support plate (60) is provided with a plurality of vent holes (61) communicating with the exhaust space (601).

9. The battery cell according to claim 8, characterized in that, The first weak portion (20) along the first wall (11) in the first direction (Z) of the first wall (11) is projected onto the bottom plate (60) in at least a portion of the distribution area (611) of the plurality of vent holes (61), and / or, the second weak portion (30) along the first wall (11) in the first direction (Z) of the first wall (11) of the bottom plate (60) is projected onto the bottom plate (60) in at least a portion of the distribution area (611) of the plurality of vent holes (61).

10. The battery cell according to claim 8, characterized in that, The battery cell also includes a support member (70), which is connected between the base plate (60) and the first wall (11). Multiple support members (70) are provided, and multiple support members (70) are arranged around the explosion-proof area (201) at least.

11. The battery cell according to claim 10, characterized in that, The battery cell also includes a first positioning element (62) and a second positioning element (71), one of which is located on the bottom plate (60) and the other is located on the support element (70). The first positioning element (62) and the second positioning element (71) are connected in cooperation.

12. A battery pack, characterized in that, Includes the battery cell as described in any one of claims 1-11.

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