Battery monomer and battery pack

Abstract

The utility model relates to the technical field of new energy batteries, and discloses a single battery and a battery pack, the single battery comprises: a housing provided with an accommodating cavity and having a first wall surface and a second wall surface; the cover plate covers and seals the containing cavity in the third direction, the cover plate is provided with a first face, a second face and a third face, the first face deviates from the shell in the third direction, the second face faces the shell in the third direction, the third face is connected between the first face and the second face, and the third face is matched with the first wall face in a stopping mode; the limiting structure comprises a limiting groove and a limiting table, one of the first wall surface and the third surface is provided with the limiting groove, the other one of the first wall surface and the third surface is provided with the limiting table, and the limiting table and the limiting groove are in stopping fit in the first direction, the second direction and the third direction. Through two-time limiting, the matching stability of the cover plate and the shell during welding is improved, the distance and height difference between the welding faces of the cover plate and the shell are controlled, and the laser welding quality is improved.

Description

Technical Field

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

[0002] Square lithium batteries are a common type of battery used in battery packs today, offering advantages such as high pack efficiency. A lithium battery typically consists of a casing, a cover, and electrode components. The casing has an open top, providing space for the internal components, including the electrode components, which are then installed inside. The cover, connected to the casing, forms a sealed space, enclosing the electrode components and preventing electrolyte leakage.

[0003] Current lithium battery packaging typically employs laser welding, where the connection between the casing and the cover is sealed using laser welding. During laser welding, the gap and height difference between the welding surfaces of the casing and the cover directly affect the welding result. If the casing and cover cannot fit securely, resulting in a large gap or height difference between the welding surfaces, the welding quality will be affected. Furthermore, weld slag can fall into the casing during laser welding, causing the lithium battery to fail and compromising its safety performance. Utility Model Content

[0004] The purpose of this invention is to provide a single battery cell to solve the problem that the cover and housing cannot be stably fitted together when laser welding the cover plate and housing in the prior art; this invention also provides a battery pack.

[0005] To achieve the above objectives, this utility model provides a battery cell having intersecting first, second, and third directions, and the battery cell includes:

[0006] A housing having a receiving cavity, the housing having a first wall facing the receiving cavity and a second wall facing away from the receiving cavity;

[0007] A cover plate, which is connected to the housing and covers the receiving cavity along the third direction, the cover plate having a first surface, a second surface and a third surface, the first surface being away from the housing along the third direction, the second surface being towards the housing along the third direction, and the third surface being connected between the first surface and the second surface, and along the first direction and / or the second direction, the third surface being in stop-fitting with the first wall surface;

[0008] The limiting structure includes a limiting groove and a limiting platform. One of the first wall surface and the third surface is provided with the limiting groove, and the other is provided with the limiting platform. The limiting platform is embedded in the limiting groove, and the limiting platform and the limiting groove are mutually stopped along the first direction, the second direction, and the third direction.

[0009] Preferably, the third surface includes a first stepped surface, a second stepped surface, and a third stepped surface. The second stepped surface connects the first stepped surface and the third stepped surface, and the third stepped surface connects to the second surface. The second stepped surface is disposed opposite to the housing along the third direction. The third stepped surface stops and cooperates with the first wall surface. The limiting groove is disposed on the third stepped surface, and the limiting platform is disposed on the first wall surface, or the limiting platform is disposed on the third stepped surface, and the limiting groove is disposed on the first wall surface.

[0010] The housing also has an end face, which is disposed opposite to the cover plate along the third direction, and the second stepped surface overlaps the end face along the third direction.

[0011] Preferably, the limiting groove has a first groove surface, a second groove surface, and a third groove surface. Along the first direction and / or the second direction, the first groove surface is disposed opposite to the first wall surface, the second groove surface is disposed opposite to the second step surface along the third direction, and the third groove surface intersects the first groove surface and the second groove surface in pairs.

[0012] The limiting platform has a first limiting surface, a second limiting surface and a third limiting surface. The first limiting surface is in contact with the first groove surface, the second limiting surface is in contact with the second groove surface, and the third limiting surface is in contact with the third groove surface.

[0013] Preferably, along the third direction, the limiting groove extends to the second step surface, and the limiting platform also has a top surface disposed opposite to the second limiting surface along the third direction, the top surface being flush with the end surface.

[0014] Preferably, along the direction perpendicular to the third direction, the dimension between the first limiting surface and the first wall surface is b, and the dimension between the first wall surface and the second wall surface is δ, where 0.1≤b≤δ / 2;

[0015] Along a direction perpendicular to the third direction, the dimension between the first groove surface and the third step surface is B, where 0 ≤ Bb ≤ 0.1.

[0016] Preferably, along the direction perpendicular to the third direction, the dimension between the first groove surface and the first step surface is A, -0.2≤A-(δ+b)≤0.2.

[0017] Preferably, along the third direction, the dimension between the second groove surface and the second step surface is H, and the dimension between the second limiting surface and the end face is h, where 0≤Hh≤0.1.

[0018] Preferably, along the third direction, the dimension between the first surface and the second surface is α, where α / 10 ≤ H ≤ α / 2.

[0019] Preferably, both the housing and the cover plate are provided with a radius (R-angle), and both the limiting groove and the limiting platform are located at the radius (R-angle).

[0020] This utility model also provides a battery pack, including the battery cells described in any of the above technical solutions.

[0021] Compared with the prior art, the beneficial effects of this utility model embodiment of a battery cell and battery pack are as follows: the first wall surface of the housing and the third surface of the cover plate stop and cooperate along the first direction and / or the second direction. After the housing and the cover plate are assembled, they are limited by the first wall surface and the third surface in the first and second directions, respectively. The first wall surface and the third surface limit the housing and the cover plate. At the same time, a limiting structure formed by a limiting groove and a limiting platform is provided between the first wall surface of the housing and the third surface of the cover plate. After the limiting platform is embedded in the limiting groove, the limiting platform and the limiting groove stop along the first direction, the second direction and the third direction, respectively, to limit the housing and the cover plate in three directions. The above-mentioned limiting improves the fit stability of the cover plate and the housing during welding, controls the distance and height difference between the two welding surfaces, improves the laser welding quality and improves the safety performance of the lithium battery. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of a single battery cell of this utility model;

[0023] Figure 2 yes Figure 1 A schematic diagram of the structure of the cover plate of the battery cell;

[0024] Figure 3 yes Figure 2 A magnified view of the cover plate at point M;

[0025] Figure 4 yes Figure 1 A schematic diagram of the casing of a single battery cell;

[0026] Figure 5 yes Figure 4 A magnified view of the shell at point N;

[0027] Figure 6 This is a cross-sectional view of the housing and cover plate of the battery cell of this utility model at the limiting structure;

[0028] Figure 7 yes Figure 6 An exploded view of the shell and cover plate at the limiting structure;

[0029] Figure 8 yes Figure 7 A schematic diagram showing the dimensions of the shell and cover at the limiting structure.

[0030] In the figure, 1. Shell, 11. Receiving cavity, 12. First wall surface, 13. Second wall surface, 14. End face, 2. Cover plate, 21. First surface, 22. Second surface, 23. Third surface, 231. First step surface, 232. Second step surface, 233. Third step surface, 3. Limiting structure, 31. Limiting groove, 311. First groove surface, 312. Second groove surface, 313. Third groove surface, 32. Limiting platform, 321. First limiting surface, 322. Second limiting surface, 323. Third limiting surface, 324. Top surface, 4. R angle, 5. Electrode assembly, 6. Electrode post, 7. Explosion-proof valve, 8. Liquid injection port, X. First direction, Y. Second direction, Z. Third direction. Detailed Implementation

[0031] 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.

[0032] A preferred embodiment of a battery cell of this utility model is as follows: Figures 1 to 8 As shown, the battery cell includes a housing 1, a cover plate 2, and a limiting structure 3. The battery cell also has a first direction X, a second direction Y, and a third direction Z that intersect each other. In this embodiment, the first direction X is the thickness direction of the battery cell, the second direction Y is the width direction of the battery cell, and the third direction Z is the height direction of the battery cell. The first direction X, the second direction Y, and the third direction Z are perpendicular to each other.

[0033] The housing 1 has a receiving cavity 11 for installing the electrode assembly 5 of the battery cell. The housing 1 has a first wall surface 12 facing the receiving cavity 11 and a second wall surface 13 facing away from the receiving cavity 11. That is, the first wall surface 12 is the cavity wall of the receiving cavity 11, and the second wall surface 13 is the outer surface of the housing 1.

[0034] The cover plate 2 is connected to the housing 1 and seals the receiving cavity 11 in the third direction Z, forming an integral sealed structure after the cover plate 2 is connected to the housing 1. The cover plate 2 is also provided with an electrode post 6, an explosion-proof valve 7, and a liquid injection port 8. The electrode post 6 is electrically connected to the electrode assembly 5 in the receiving cavity 11 to enable the battery cell to complete the charging and discharging function. The liquid injection port 8 is a through hole provided on the cover plate 2. After the cover plate 2 is connected and sealed to the housing 1, electrolyte can be injected into the receiving cavity 11 of the housing 1 through the liquid injection port 8. The explosion-proof valve 7 can be opened in the event of thermal runaway of the battery cell to discharge the generated heat and gas, preventing further risks such as explosion.

[0035] The cover plate 2 has a first surface 21, a second surface 22 and a third surface 23. The first surface 21 is away from the housing 1 along the third direction Z, the second surface 22 is towards the housing 1 along the third direction Z, and the third surface 23 is connected between the first surface 21 and the second surface 22. That is, in this embodiment, the first surface 21 is the top surface of the cover plate 2, the second surface 22 is the bottom surface of the cover plate 2, and the third surface 23 is the side surface connected between the first surface 21 and the second surface 22.

[0036] Along the first direction X and / or the second direction Y, the third surface 23 engages with the first wall surface 12. In this embodiment, the battery cell is a square battery, and the third surface 23 of the cover plate 2 is arranged in a closed rectangle, with the third surface 23 facing the first wall surface 12 of the housing 1 along the first direction X and the second direction Y. After the cover plate 2 is assembled with the housing 1, the third surface 23 engages with the first wall surface 12, providing initial positioning of the housing 1 and the cover plate 2 in the first direction X and the second direction Y.

[0037] At least two limiting structures 3 are spaced apart, increasing the number of limiting structures 3. This ensures that the forces on the housing 1 and the cover plate 2 are balanced at each limiting structure 3, increasing the stability of the assembly between the housing 1 and the cover plate 2. In this embodiment, the limiting structures 3 are spaced apart in a Z-direction perpendicular to the third direction, and are symmetrical to each other to further increase the stability of the assembly between the cover plate 2 and the housing 1. In some embodiments, the limiting structures 3 can be integrally formed with the cover plate 2 or the housing 1, or they can be assembled separately.

[0038] The limiting structure 3 includes a limiting groove 31 and a limiting platform 32. One of the first wall surface 12 and the third surface 23 has a limiting groove 31, and the other has a limiting platform 32. The limiting platform 32 is embedded in the limiting groove 31 along the first direction X and / or the second direction Y. In this embodiment, the limiting groove 31 is formed on the third surface 23, and the limiting platform 32 is set on the first wall surface 12. This avoids cutting grooves on the housing 1, which would affect the strength of the housing 1, and also makes reasonable use of the size of the cover plate 2. In this embodiment, multiple limiting platforms 32 are provided on the first wall surface 12, and the limiting grooves 31 are correspondingly set on the third surface 23. Since the third surface 23 is a closed rectangle, some of the limiting platforms 32 are embedded in the limiting groove 31 along the first direction X, and some of the limiting platforms 32 are embedded in the limiting groove 31 along the second direction Y.

[0039] The limiting platform 32 and the limiting groove 31 are mutually stopped along the first direction X, the second direction Y, and the third direction Z. The limiting platform 32 and the limiting groove 31 can mutually limit each other in the first direction X, the second direction Y, and the third direction Z, thereby limiting the housing 1 and the cover plate 2 in three directions at the same time. This ensures that the position of the cover plate 2 and the housing 1 is stable during assembly, and that the relative position of the housing 1 and the cover plate 2 is within a controllable range during the welding process. This ensures that the steps and gaps of the welded surface are within a controllable range after the fit, and improves the stability of the welding quality.

[0040] The first wall surface 12 of the battery cell housing 1 and the third surface 23 of the cover plate 2 stop along the first direction X and / or the second direction Y. After the housing 1 and the cover plate 2 are assembled, they are limited by the first wall surface 12 and the third surface 23 in the first direction X and the second direction Y, respectively. The first wall surface 12 and the third surface 23 limit the housing 1 and the cover plate 2. At the same time, a limiting structure 3 is formed by a limiting groove 31 and a limiting platform 32 between the first wall surface 12 of the housing 1 and the third surface 23 of the cover plate 2. After the limiting platform 32 is embedded in the limiting groove 31, the limiting platform 32 and the limiting groove 31 stop along the first direction X, the second direction Y and the third direction Z, respectively, thus limiting the housing 1 and the cover plate 2 in three directions. The above-mentioned limiting improves the fit stability of the cover plate 2 and the housing 1 during welding, controls the distance and height difference between the two welding surfaces, improves the laser welding quality and improves the safety performance of the lithium battery.

[0041] In some embodiments, the third surface 23 includes a first step surface 231, a second step surface 232, and a third step surface 233. The second step surface 232 is connected between the first step surface 231 and the third step surface 233, and the third step surface 233 is connected to the second surface 22. The second step surface 232 is disposed opposite to the housing 1 along the third direction Z. The third step surface 233 is in stop-fitting with the first wall surface 12. The limiting groove 31 is disposed on the third step surface 233, and the limiting platform 32 is disposed on the first wall surface 12, or the limiting platform 32 is disposed on the third step surface 233, and the limiting groove 31 is disposed on the first wall surface 12. The housing 1 also has an end face 14, which is disposed opposite to the cover plate 2 along the third direction Z. The second step surface 232 overlaps the end face 14 along the third direction Z.

[0042] The cover plate 2 is configured with a stepped structure. In this embodiment, the limiting groove 31 is formed on the third stepped surface 233, the limiting platform 32 is provided on the first wall surface 12, and the second stepped surface 232 overlaps the end face 14 of the housing 1 along the third direction Z. In other embodiments, the limiting platform 32 can also be provided on the third stepped surface 233, and the limiting groove 31 can be formed on the first wall surface 12.

[0043] After the third step surface 233 contacts the first wall surface 12, the first wall surface 12 of the housing 1 and the third step surface 233 engage in a stop-fitting action, limiting the position in the first direction X and the second direction Y. The second step surface 232 of the cover plate 2 overlaps on the end face 14 of the housing 1 along the third direction Z. The end face 14 can limit the second step surface 232 in the third direction Z. The third step surface 233 and the second step surface 232 cooperate with each other, so that the housing 1 provides limiting action on the cover plate 2 in the first direction X, the second direction Y and the third direction Z, reducing the relative displacement that may occur between the housing 1 and the cover plate 2 during welding.

[0044] In some embodiments, the limiting groove 31 has a first groove surface 311, a second groove surface 312, and a third groove surface 313. Along the first direction X and / or the second direction Y, the first groove surface 311 is disposed opposite to the first wall surface 12, the second groove surface 312 is disposed opposite to the second step surface 232 along the third direction Z, and the third groove surface 313 intersects the first groove surface 311 and the second groove surface 312 in pairs. The limiting platform 32 has a first limiting surface 321, a second limiting surface 322, and a third limiting surface 323. The first limiting surface 321 is attached to the first groove surface 311, the second limiting surface 322 is attached to the second groove surface 312, and the third limiting surface 323 is attached to the third groove surface 313.

[0045] After the first groove surface 311 of the limiting groove 31 is attached to the first limiting surface 321 of the limiting platform 32, the housing 1 and the cover plate 2 are limited by a stop along the first direction X and / or the second direction Y. After the second groove surface 312 of the limiting groove 31 is attached to the second limiting surface 322 of the limiting platform 32, the housing 1 and the cover plate 2 are limited by a stop along the third direction Z. After the third groove surface 313 of the limiting groove 31 is attached to the third limiting surface 323 of the limiting platform 32, the housing 1 and the cover plate 2 are limited by a stop along the first direction X and / or the second direction Y. Since the third groove surface 313 and the first groove surface 311 intersect and their limiting directions are different, the three-way limiting between the housing 1 and the cover plate 2 is guaranteed.

[0046] In some embodiments, along the third direction Z, the limiting groove 31 extends to the second step surface 232, and the limiting platform 32 also has a top surface 324 disposed opposite to the second limiting surface 322 along the third direction Z, and the top surface 324 is flush with the end surface 14.

[0047] The limiting groove 31 is connected to the second step surface 232 in the third direction Z. After the second step surface 232 overlaps with the end face 14 of the limiting platform 32, the second step surface 232 and the end face 14 can be used to limit the housing 1 and the cover plate 2 in the third direction Z. In addition, after the top surface 324 of the limiting platform 32 is flush with the end face 14 of the housing 1, the height difference between the end face 14 of the housing 1 and the top surface of the limiting platform 32 can be avoided, and there is no need to form a separate top surface in the limiting groove 31, which is convenient for processing.

[0048] In some embodiments, along the direction perpendicular to the third direction Z, the dimension between the first limiting surface 321 and the first wall surface 12 is b, and the dimension between the first wall surface 12 and the second wall surface 13 is δ, 0.1≤b≤δ / 2; along the direction perpendicular to the third direction Z, the dimension between the first groove surface 311 and the third step surface 233 is B, 0≤Bb≤0.1.

[0049] When the housing 1 and the cover plate 2 are assembled, the limiting groove 31 and the limiting platform 32 cooperate by utilizing the elastic deformation capacity of the housing 1 and the cover plate 2. Therefore, the various mating surfaces of the limiting platform 32 and the limiting groove 31 need to meet certain dimensions to effectively cooperate and achieve the function of limiting the housing 1 and the cover plate 2.

[0050] Along the direction Z perpendicular to the third third direction, the dimension b between the first limiting surface 321 and the first wall surface 12 is the shortest straight-line distance between any point on the first limiting surface 321 and the first wall surface 12; the dimension δ between the first wall surface 12 and the second wall surface 13 is the thickness of the shell 1; along the direction Z perpendicular to the third third direction, the dimension B between the first groove surface 311 and the third step surface 233 is the shortest straight-line distance between any point on the intersection edge of the first groove surface 311 and the second groove surface 312 and the third step surface 233.

[0051] If b is too small, the stabilizing effect of the limiting platform 32 and the cover plate 2 after mating will be poor, and the cover plate 2 will easily loosen, failing to achieve the corresponding limiting effect. If b is too large, the fixing structure will protrude excessively, exceeding the elastic deformation limit of the cover plate 2 and the shell 1, making it difficult for the cover plate 2 and the shell 1 to fit together. If the size of b does not meet the requirements, the limiting groove 31 and the limiting platform 32 will easily loosen or form gaps after mating, affecting the fitting effect. When 0.1≤b≤δ / 2 and 0≤Bb≤0.1 are satisfied, the fitting effect of the shell 1 and the cover plate 2 can be guaranteed.

[0052] In some embodiments, the dimension between the first groove surface 311 and the first step surface 231 along the direction perpendicular to the third third direction Z is A, -0.2≤A-(δ+b)≤0.2.

[0053] Along the direction Z perpendicular to the third third, the dimension A between the first groove surface 311 and the first step surface 231 is the shortest straight-line distance from any point on the first groove surface 311 to the first step surface 231. When dimension A does not meet the requirements, there will be a large step height difference between the cover plate 2 and the shell 1 on the welded surface after mating, which will affect the welding effect. When -0.2≤A-(δ+b)≤0.2 is satisfied, the welding accuracy between the cover plate 2 and the shell 1 can be guaranteed.

[0054] In some embodiments, along the third direction Z, the dimension between the second groove surface 312 and the second step surface 232 is H, and the dimension between the second limiting surface 322 and the end surface 14 is h, where 0≤Hh≤0.1.

[0055] Along the third direction Z, the dimension H between the second groove surface 312 and the second step surface 232 is the height of the limiting groove 31 in the third direction Z, and the dimension h between the second limiting surface 322 and the end face 14 is the height of the limiting platform 32 in the third direction Z. When 0≤Hh≤0.1, it can be ensured that the limiting platform 32 is embedded in the limiting groove 31 and that there is no large height difference between the second step surface 232 and the end face 14.

[0056] In some embodiments, the dimension between the first face 21 and the second face 22 along the third direction Z is α, where α / 10≤H≤α / 2.

[0057] The dimension α between the first surface 21 and the second surface 22 is the thickness of the cover plate 2. If H is too small, the limiting groove 31 and the limiting platform 32 are prone to loosening and falling off after they are engaged, resulting in poor engagement. If H is too large, the gap between the limiting groove 31 and the limiting platform 32 is too large after they are engaged, affecting the engagement effect. If h is too small, the engagement is not tight. If h is too large, it is difficult to engage, and the cover plate 2 may deform after engagement.

[0058] In some embodiments, both the housing 1 and the cover plate 2 are provided with an R-angle 4, and the limiting groove 31 and the limiting platform 32 are both provided at the R-angle 4.

[0059] The limiting groove 31 and limiting platform 32 at R-angle 4 are arc-shaped extending around the third direction Z. After the first groove surface 311 and the first limiting surface 321 of the limiting groove 31 and the limiting platform 32 are attached, they can simultaneously have the limiting effect of the first direction X and the second direction Y, which improves the cooperation effect between the shell 1 and the cover plate 2.

[0060] When the cover plate 2 of the battery cell in this application is welded and assembled with the housing 1, the following dimensions are adjusted: B between the first groove surface 311 and the third step surface 233 along the direction perpendicular to the third third direction; b between the first limiting surface 321 and the first wall surface 12; δ between the first wall surface 12 and the second wall surface 13; A between the first groove surface 311 and the first step surface 231; H between the second groove surface 312 and the second step surface 232; h between the second limiting surface 322 and the end face 14; and α between the first surface 21 and the second surface 22. The welding qualification rate is judged. When there are unwelded areas, burst points, pinholes, or cracks, the welding is considered unqualified.

[0061] The welding pass rates of each embodiment and comparative example are shown in Table 1. Except for the dimensions in the table, the other experimental conditions are the same. Each embodiment or comparative example welded 50 cover plates 2 and shells 1, and the welding results were statistically analyzed. Welding pass rate = (1 - number of unqualified welds / number of welded cover plates and shells) × 100%.

[0062] Table 1

[0063] B / mm b / mm δmm A / mm H / mm h / mm αmm pass rate Example 1 0.2 0.1 0.6 0.8 0.8 0.7 2 100％ Example 2 0.3 0.2 0.6 0.9 0.8 0.7 2 100％ Example 3 0.4 0.3 0.6 1 0.8 0.7 2 100％ Example 4 0.4 0.3 0.6 1.1 0.8 0.7 2 100％ Example 5 0.4 0.3 0.6 0.7 0.8 0.7 2 100％ Example 6 0.4 0.4 0.8 1.2 0.8 0.7 2 100％ Example 7 0.4 0.4 0.8 1.2 0.2 0.1 2 100％ Example 8 0.4 0.4 0.8 1.2 0.4 0.3 2 100％ Example 9 0.4 0.4 0.8 1.2 0.6 0.5 2 100％ Example 10 0.4 0.4 0.8 1.2 0.8 0.7 2 100％ Example 11 0.4 0.4 0.8 1.2 1 0.9 2 100％ Test Example 1 0.1 0.05 0.6 0.8 0.8 0.7 2 92％ Test Example 2 0.5 0.4 0.6 0.9 0.8 0.7 2 84％ Test Example 3 0.5 0.5 0.6 0.9 0.8 0.7 2 88％ Test Example 4 0.2 0.3 0.6 0.9 0.8 0.7 2 70％ Test Example 5 0.5 0.3 0.6 0.9 0.8 0.7 2 80％ Test Example 6 0.4 0.3 0.6 1.2 0.8 0.7 2 72％ Test Example 7 0.4 0.3 0.6 0.6 0.8 0.7 2 78％ Test Example 8 0.4 0.4 0.8 1.2 0.1 0.1 2 90％ Test Example 9 0.4 0.4 0.8 1.2 1.1 1 2 88％ Test Case 10 0.4 0.4 0.8 1.2 0.8 0.9 2 74％ Test Example 11 0.4 0.4 0.8 1.2 0.8 0.5 2 80％

[0064] As shown in Table 1 above, the welding qualification rate can reach 100% when the following conditions are met: 0.1≤b≤δ / 2, 0≤Bb≤0.1, -0.2≤A-(δ+b)≤0.2, 0≤Hh≤0.1, and α / 10≤H≤α / 2.

[0065] In summary, this utility model embodiment provides a battery cell in which the first wall surface of the casing and the third surface of the cover plate stop and cooperate along the first and / or second directions. After the casing and the cover plate are assembled, they are limited by the first wall surface and the third surface in the first and second directions, respectively, and the first wall surface and the third surface provide initial positioning of the casing and the cover plate. At the same time, a positioning structure is formed by a positioning groove and a positioning platform between the first wall surface of the casing and the third surface of the cover plate. After the positioning platform is embedded in the positioning groove, the positioning platform and the positioning groove cooperate with the stop along the first, second, and third directions, and the casing and the cover plate are again positioned in three directions. Through the two positioning, the fit stability of the cover plate and the casing during welding is improved, the distance and height difference between the two welding surfaces are controlled, the laser welding quality is improved, and the safety performance of the lithium battery is improved.

[0066] 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, The battery cell has a first direction, a second direction, and a third direction that intersect each other in pairs, and the battery cell includes: A housing having a receiving cavity, the housing having a first wall facing the receiving cavity and a second wall facing away from the receiving cavity; A cover plate, which is connected to the housing and covers the receiving cavity along the third direction, the cover plate having a first surface, a second surface and a third surface, the first surface being away from the housing along the third direction, the second surface being towards the housing along the third direction, and the third surface being connected between the first surface and the second surface, and along the first direction and / or the second direction, the third surface being in stop-fitting with the first wall surface; The limiting structure includes a limiting groove and a limiting platform. One of the first wall surface and the third surface is provided with the limiting groove, and the other is provided with the limiting platform. The limiting platform is embedded in the limiting groove, and the limiting platform and the limiting groove are mutually stopped along the first direction, the second direction, and the third direction.

2. The battery cell according to claim 1, characterized in that, The third surface includes a first stepped surface, a second stepped surface, and a third stepped surface. The second stepped surface connects the first stepped surface and the third stepped surface. The third stepped surface is connected to the second surface. The second stepped surface is disposed opposite to the housing along the third direction. The third stepped surface stops and cooperates with the first wall surface. The limiting groove is disposed on the third stepped surface and the limiting platform is disposed on the first wall surface, or the limiting platform is disposed on the third stepped surface and the limiting groove is disposed on the first wall surface. The housing also has an end face, which is disposed opposite to the cover plate along the third direction, and the second stepped surface overlaps the end face along the third direction.

3. The battery cell according to claim 2, characterized in that, The limiting groove has a first groove surface, a second groove surface, and a third groove surface. Along the first direction and / or the second direction, the first groove surface is disposed opposite to the first wall surface, the second groove surface is disposed opposite to the second step surface along the third direction, and the third groove surface intersects the first groove surface and the second groove surface in pairs. The limiting platform has a first limiting surface, a second limiting surface and a third limiting surface. The first limiting surface is in contact with the first groove surface, the second limiting surface is in contact with the second groove surface, and the third limiting surface is in contact with the third groove surface.

4. The battery cell according to claim 3, characterized in that, Along the third direction, the limiting groove extends to the second step surface, and the limiting platform also has a top surface that is disposed opposite to the second limiting surface along the third direction, and the top surface is flush with the end surface.

5. The battery cell according to claim 4, characterized in that, Along the direction perpendicular to the third direction, the dimension between the first limiting surface and the first wall surface is b, and the dimension between the first wall surface and the second wall surface is δ, 0.1≤b≤δ / 2; Along a direction perpendicular to the third direction, the dimension between the first groove surface and the third step surface is B, where 0 ≤ Bb ≤ 0.

1.

6. The battery cell according to claim 5, characterized in that, Along the direction perpendicular to the third direction, the dimension between the first groove surface and the first step surface is A, -0.2≤A-(δ+b)≤0.

2.

7. The battery cell according to claim 6, characterized in that, Along the third direction, the dimension between the second groove surface and the second step surface is H, and the dimension between the second limiting surface and the end face is h, where 0≤Hh≤0.

1.

8. The battery cell according to claim 7, characterized in that, Along the third direction, the dimension between the first face and the second face is α, where α / 10 ≤ H ≤ α / 2.

9. The battery cell according to any one of claims 1-8, characterized in that, Both the housing and the cover plate are provided with a radius (R-angle), and the limiting groove and the limiting platform are both located at the radius (R-angle).

10. A battery pack, characterized in that, Includes the battery cell described in any one of claims 1-9.

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