Single cells, battery packs and electrical devices

Abstract

This application discloses a single-cell battery, a battery pack, and an electrical device, belonging to the field of battery technology. It includes: a housing and a cover plate connected to the housing, the cover plate having an explosion-proof hole; an explosion-proof valve covering the explosion-proof hole, the explosion-proof valve including a support portion, a weak portion, and a protrusion, the support portion being connected around the weak portion, the weak portion being connected around the protrusion, the support portion being connected to the cover plate, the protrusion protruding towards the side away from the electrode assembly, and the protrusion having a recessed portion towards the side closer to the electrode assembly. The weak portion includes a first surface of the cover plate close to the electrode assembly in the thickness direction. In the thickness direction, the minimum dimension C mm is between the recessed portion and the first surface, and the maximum dimension D mm is between the protrusion and the first surface, satisfying: 0.3 ≤ D - C ≤ 0.6. By limiting the difference range between the protrusion and the recessed portion in the thickness direction, it is ensured that the explosion-proof valve can effectively absorb and disperse stress, avoiding problems such as deformation cracking or premature valve opening.

Description

Technical Field

[0001] This application belongs to the field of battery technology, specifically relating to a single cell, a battery pack, and an electrical device. Background Art

[0002] Lithium-ion batteries are widely used in various fields such as transportation power supplies, power storage, new energy storage power supplies, and aerospace and military industries due to their advantages such as large capacity, high operating voltage, strong charge retention, and long cycle life. The cover plate of the battery typically integrates structures such as terminals and explosion-proof valves. The explosion-proof valve's main function is to relieve pressure and vent gas, allowing the directional release of high-temperature, high-pressure gas inside the battery cell in the event of thermal runaway due to mechanical impact, internal abnormal short circuits, or other reasons, thereby improving the safety performance of the battery pack. However, during the cell manufacturing process, such as electrolyte injection, pre-charge formation, and capacity testing, repeated positive and negative pressure differences exist between the battery's internal environment and the external environment, causing problems such as deformation, cracking, and premature opening of the explosion-proof valve, seriously affecting the battery manufacturing yield and safety performance. Summary of the Invention

[0003] Purpose of the invention: This application provides a single cell, a battery pack, and an electrical device, aiming to solve the technical problems of deformation, cracking, and premature opening of the explosion-proof valve due to pressure difference during battery manufacturing.

[0004] Technical solution: This application provides a single-cell battery, including:

[0005] The housing has a receiving cavity;

[0006] Electrode assembly, the electrode assembly is located within the receiving cavity;

[0007] A cover plate is connected to the housing and seals the receiving cavity; the cover plate is provided with explosion-proof holes.

[0008] An explosion-proof valve, with an explosion-proof valve cover sealing the explosion-proof hole, includes a support part, a weak part, and a protrusion. The support part is connected around the weak part, and the weak part is connected around the protrusion. The support part is connected to a cover plate. The weak part is configured to be destroyed when subjected to a preset pressure impact. The protrusion protrudes from the connection point with the weak part toward the side away from the electrode assembly. The protrusion has a recess that is recessed toward the side closer to the electrode assembly.

[0009] The weak part includes the first surface of the cover plate close to the electrode assembly in the thickness direction. In the thickness direction, the concave part has a minimum dimension C mm between itself and the first surface, and the protruding part has a maximum dimension D mm between itself and the first surface, satisfying: 0.3≤DC≤0.6.

[0010] In some embodiments, the protrusion includes a first sub-protrusion and a second sub-protrusion, the first sub-protrusion being disposed around the second sub-protrusion, and the recess being disposed between the first sub-protrusion and the second sub-protrusion and connected to the first sub-protrusion and the second sub-protrusion respectively.

[0011] In some embodiments, in the thickness direction, the first sub-protrusion has a minimum dimension B mm between it and the first surface, satisfying: 0.05≤BC≤0.15.

[0012] In some embodiments, the support portion has a maximum dimension A mm in the thickness direction, and the single cell satisfies: A < C, 0.4 ≤ A ≤ 0.6.

[0013] In some embodiments, a single cell satisfies: 0.7 ≤ D ≤ 1.2.

[0014] In some embodiments, the support portion is connected to the side of the cover plate near the electrode assembly, and the protrusion extends into the explosion-proof hole.

[0015] In some embodiments, a limiting groove is provided on the side of the cover plate near the electrode assembly. The limiting groove surrounds the explosion-proof hole. The limiting groove is provided on the side of the cover plate near the electrode assembly, and the bearing part is provided in the limiting groove.

[0016] In some embodiments, along the thickness direction, the bottom wall of the limiting groove and the side of the cover plate near the electrode assembly have a minimum dimension E mm, and the bearing portion has a maximum dimension A mm, satisfying: E≥A.

[0017] Accordingly, this application provides a battery pack including the aforementioned single battery cell.

[0018] Accordingly, embodiments of this application provide an electrical device, including the aforementioned single battery cell, or including the aforementioned battery pack.

[0019] Beneficial Effects: The single-cell battery of this application embodiment includes a casing, an electrode assembly, a cover plate, and an explosion-proof valve. The casing has a receiving cavity; the electrode assembly is located in the receiving cavity; the cover plate is connected to the casing and seals the receiving cavity, and the cover plate has an explosion-proof hole; the explosion-proof valve seals the explosion-proof hole, and the explosion-proof valve includes a supporting part, a weak part, and a protruding part. The supporting part is connected around the weak part, and the weak part is connected around the protruding part. The supporting part is connected to the cover plate. The weak part is configured to be destroyed when subjected to a preset pressure impact. The protruding part protrudes from the connection with the weak part toward the side away from the electrode assembly, and the protruding part has a recessed part toward the side closer to the electrode assembly. The weak part includes a first surface of the cover plate close to the electrode assembly in the thickness direction. In the thickness direction, the minimum dimension C mm is between the recessed part and the first surface, and the maximum dimension D mm is between the protruding part and the first surface, satisfying: 0.3 ≤ DC ≤ 0.6. By setting protrusions and recesses and further limiting the range of the difference between the protrusions and recesses in the thickness direction, it can be ensured that the explosion-proof valve can absorb and disperse the stress brought to the explosion-proof valve by the pressure difference between the cavity and the outside of the shell during the production of a single cell. This avoids the explosion-proof valve from deforming due to stress concentration, which could lead to cracking or premature opening of the valve. As a result, the production yield of single cells can be effectively improved, as well as the safety and reliability of single cells.

[0020] The battery pack of this application embodiment includes the above-described single battery cell, and therefore the battery pack can have all the technical features and beneficial effects of the above-described single battery cell, which will not be repeated here.

[0021] The electrical device in this application includes the above-mentioned single battery or battery pack. Therefore, the electrical device can have all the technical features and beneficial effects of the above-mentioned single battery or battery pack, which will not be repeated here. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is an exploded view of a single battery cell according to an embodiment of this application;

[0024] Figure 2 This is a cross-sectional view of a cover plate according to an embodiment of this application;

[0025] Figure 3 This is a top view of an explosion-proof valve according to an embodiment of this application;

[0026] Figure 4This is a bottom view of an explosion-proof valve according to an embodiment of this application;

[0027] Figure 5 This is a top view of an explosion-proof valve according to another embodiment of this application;

[0028] Figure 6 This is a bottom view of an explosion-proof valve according to another embodiment of this application;

[0029] Figure 7 This is a cross-sectional view of an explosion-proof valve according to an embodiment of this application.

[0030] Reference numerals: 1. Housing; 2. Electrode assembly; 3. Cover plate; 4. Explosion-proof valve; 10. Receiving cavity; 30. Explosion-proof hole; 31. Limiting groove; 40. Bearing part; 41. Weak part; 42. Protrusion; 310. Bottom wall; 410. First surface; 411. Score; 420. Recess; 421. First sub-protrusion; 422. Second sub-protrusion; X, Thickness direction. Detailed Implementation

[0031] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0032] In the description of this application, it should be understood that the terms "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application 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 on this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, and "at least one" can mean one, two, or more, unless otherwise explicitly specified. In the description of this application, "perpendicular" means completely perpendicular to 90° or almost completely perpendicular, for example, the range of included angles from 80° to 100° is considered perpendicular. Similarly, "parallel" means completely parallel or almost completely parallel, for example, the range of completely parallel angles from 10° is considered parallel.

[0033] The applicant notes that lithium-ion batteries, due to their advantages such as large capacity, high operating voltage, strong charge retention, and long cycle life, are currently widely used in various fields including transportation power supplies, power storage, new energy storage power supplies, and aerospace and military industries. The cover plate in a battery typically integrates structures such as terminals and explosion-proof valves. The explosion-proof valve's main function is to release pressure and vent gas, allowing the directional release of high-temperature, high-pressure gas inside the battery cell when thermal runaway occurs due to mechanical impact, internal abnormal short circuits, or other reasons, thereby improving the safety performance of the battery pack. However, during the cell manufacturing process, including electrolyte injection, pre-charge formation, and capacity testing, repeated positive and negative pressure differences exist between the battery's internal environment and the external environment, leading to problems such as deformation, cracking, and premature opening of the explosion-proof valve, severely affecting battery manufacturing yield and safety performance.

[0034] In view of this, embodiments of this application provide a single battery, a battery pack, and an electrical device. The single battery of this application includes a housing, an electrode assembly, a cover plate, and an explosion-proof valve. The housing has a receiving cavity; the electrode assembly is located in the receiving cavity; the cover plate is connected to the housing and seals the receiving cavity, and the cover plate has an explosion-proof hole; the explosion-proof valve seals the explosion-proof hole, and the explosion-proof valve includes a supporting part, a weak part, and a protruding part. The supporting part is connected around the weak part, and the weak part is connected around the protruding part. The supporting part is connected to the cover plate. The weak part is configured to be destroyed when subjected to a preset pressure impact. The protruding part protrudes from the connection point with the weak part toward the side away from the electrode assembly, and the protruding part has a recessed part toward the side closer to the electrode assembly. The weak part includes a first surface of the cover plate close to the electrode assembly in the thickness direction. In the thickness direction, the minimum dimension C mm is between the recessed part and the first surface, and the maximum dimension D mm is between the protruding part and the first surface, satisfying: 0.3 ≤ DC ≤ 0.6. By setting protrusions and recesses and further limiting the range of the difference between the protrusions and recesses in the thickness direction, it can be ensured that the explosion-proof valve can absorb and disperse the stress brought to the explosion-proof valve by the pressure difference between the cavity and the outside of the shell during the production of a single cell. This avoids the explosion-proof valve from deforming due to stress concentration, which could lead to cracking or premature opening of the valve. As a result, the production yield of single cells can be effectively improved, as well as the safety and reliability of single cells.

[0035] In this application, a single battery cell may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries, etc., and the embodiments of this application are not limited to this. A single battery cell may be cylindrical, flat, cuboid, or other shapes, etc., and the embodiments of this application are not limited to this either. Single batteries are generally classified into three types according to their packaging method: cylindrical single batteries, square single batteries, and pouch single batteries, and the embodiments of this application are not limited to this either.

[0036] The single-cell battery, battery pack, and power-consuming device of this application will be described in detail below with reference to the accompanying drawings. Unless otherwise specified, the features of the following embodiments and implementations can be combined with each other.

[0037] Figure 1 This is an exploded view of a single battery cell according to an embodiment of this application; Figure 2 This is a cross-sectional view of a cover plate 3 according to an embodiment of this application; Figure 3 This is a top view of an explosion-proof valve 4 according to an embodiment of this application; Figure 4 This is a bottom view of an explosion-proof valve 4 according to an embodiment of this application; Figure 5 This is a top view of an explosion-proof valve 4 according to another embodiment of this application; Figure 6 This is a bottom view of an explosion-proof valve 4 according to another embodiment of this application; Figure 7 This is a cross-sectional view of an explosion-proof valve 4 according to an embodiment of this application.

[0038] refer to Figures 1 to 7This application provides a single-cell battery, including a housing 1, an electrode assembly 2, a cover plate 3, and an explosion-proof valve 4. The housing 1 has a receiving cavity 10; the electrode assembly 2 is located within the receiving cavity 10; the cover plate 3 is connected to the housing 1 and seals the receiving cavity 10, the cover plate 3 has an explosion-proof hole 30, and the explosion-proof valve 4 seals the explosion-proof hole 30. The explosion-proof valve 4 includes a supporting part 40, a weak part 41, and a protruding part 42. The supporting part 40 is connected to the weak part 41 around the weak part 41, and the weak part 41 is connected to the protruding part 42 around the weak part 42. The supporting part 40 is connected to the cover plate 3, and the weak part 41 is configured to be destroyed when subjected to a preset pressure impact. When the internal pressure of the single-cell battery is too high (e.g., due to overcharging), the weak part 41 of the explosion-proof valve 4 is destroyed by the preset pressure to release the gas inside the single-cell battery, thereby reducing the internal pressure of the single-cell battery and preventing the single-cell battery from exploding due to excessively rapid internal pressurization. The protrusion 42 protrudes from the connection point with the weak portion 41 toward the side away from the electrode assembly 2. The protrusion 42 has a recess 420 recessed toward the side closer to the electrode assembly 2. The arrangement of the protrusion 42 and the recess 420 can avoid stress concentration. The weak portion 41 includes a first surface 410 of the cover plate 3 close to the electrode assembly 2 in the thickness direction X. In the thickness direction X, the minimum dimension C mm is between the recess 420 and the first surface 410, and the maximum dimension D mm is between the protrusion 42 and the first surface 410, satisfying: 0.3 ≤ DC ≤ 0.6. By setting the protrusion 42 and the recess 420 and further limiting the range of the difference between the protrusion 42 and the recess 420 in the thickness direction X, it can be ensured that the explosion-proof valve 4 can fully absorb and disperse the stress brought to the explosion-proof valve 4 by the pressure difference between the cavity 10 and the shell 1 during the production of the single cell. This avoids the problem that the weak part 41 will deform due to the pressure difference, which could lead to cracking of the weak part 41 or premature opening of the explosion-proof valve 4. This can effectively improve the production yield of the single cell and improve the safety and reliability of the single cell.

[0039] When the difference between the maximum dimension D between the protrusion 42 and the first surface 410 and the minimum dimension C between the recess 420 and the first surface 410 is too small, the curvature of the concave surface of the recess 420 is too high and the concave area is insufficient. This makes it impossible for the explosion-proof valve 4 to effectively absorb and disperse the internal pressure in the single-cell battery manufacturing process, which can easily lead to abnormal concave deformation or even cracking of the explosion-proof valve.

[0040] When the difference between the maximum dimension D between the protrusion 42 and the first surface 410 and the minimum dimension C between the recess 420 and the first surface 410 is too large, the height of the outer convex surface of the protrusion 42 is too large. In the single-cell manufacturing process, an excessively high outer convex surface may cause the explosion-proof valve 4 to be easily damaged when it is subjected to abnormal pressure and deforms.

[0041] By limiting the range of the difference between the maximum dimension between the protrusion 42 and the first surface 410 and the minimum dimension between the recess 420 and the first surface 410, the structural strength, elastic deformation capability, and stress dispersion effect of the explosion-proof valve 4 are balanced. This avoids problems such as abnormal internal deformation and cracking of the explosion-proof valve 4 due to unreasonable dimensions, or abnormal external deformation leading to crushing. This allows the explosion-proof valve 4 to better cope with changes in the internal pressure of the individual battery, opening the valve promptly when subjected to preset pressure to prevent excessive internal pressure in the individual battery from causing fires or deflagrations. This ensures the safety and reliability of the individual battery.

[0042] In some embodiments, the maximum dimension D between the protrusion 42 and the first surface 410 in the thickness direction X satisfies: 0.7 ≤ D ≤ 1.2. Exemplarily, the maximum dimension D between the protrusion 42 and the first surface 410 in the thickness direction X can be any value from 0.7, 0.8, 0.9, 1, 1.1, 1.2, or a range between any two. When the maximum dimension D between the protrusion 42 and the first surface 410 in the thickness direction X is too small, the concave surface curvature of the recess 420 is too high, and the concave area is insufficient. This makes it difficult for the explosion-proof valve 4 to effectively absorb and disperse internal pressure during the single-cell manufacturing process, easily leading to abnormal concave deformation or even cracking of the explosion-proof valve 4. When the maximum dimension D between the protrusion 42 and the first surface 410 in the thickness direction X is too large, the height of the outer convex surface of the protrusion 42 is too large. During the single-cell manufacturing process, an excessively high outer convex surface may cause the explosion-proof valve 4 to be easily damaged when subjected to abnormal pressure and deformation. This embodiment of the application can balance the structural strength, elastic deformation capability and stress dispersion effect of the explosion-proof valve 4 by limiting the maximum dimension D between the protrusion 42 and the first surface 410 in the thickness direction X. On the one hand, it avoids the problem of abnormal deformation or even cracking of the explosion-proof valve 4 caused by insufficient concave area of ​​the recess 420. On the other hand, it can avoid the problem of being crushed when the outer convex surface of the protrusion 42 is too high due to abnormal pressure, thereby ensuring the safety and reliability of the single battery.

[0043] exist Figures 2 to 7 In the illustrated embodiment, the protrusion 42 includes a first sub-protrusion 421 and a second sub-protrusion 422. The first sub-protrusion 421 surrounds the second sub-protrusion 422, and a recess 420 is disposed between the first sub-protrusion 421 and the second sub-protrusion 422 and connected to both. The explosion-proof valve 4 can be circular or elliptical in shape. Correspondingly, the shapes of the protrusion 42 and the recess 420 can be configured to correspond to the shape of the explosion-proof valve 4, thereby helping to distribute stress more evenly on the explosion-proof valve 4. (Reference) Figure 7The cross-sectional shapes of the first sub-protrusion 421, the second sub-protrusion 422, and the recess 420 can be arc-shaped, circular arc-shaped, etc. The cross-sectional shapes of the first sub-protrusion 421, the recess 420, and the second sub-protrusion 422, which are arranged sequentially from the outside to the inside, can be wavy. This arrangement avoids stress concentration on the one hand; on the other hand, by setting the first sub-protrusion 421, the second sub-protrusion 422, and the recess 420, a larger range of elastic deformation can be achieved, thereby more effectively absorbing and dispersing the stress on the explosion-proof valve 4 caused by the pressure difference between the cavity 10 and the shell 1 during the production of a single cell, further reducing the risk of the weak part 41 cracking due to stress or the explosion-proof valve 4 opening prematurely.

[0044] exist Figure 7 In the illustrated embodiment, in the thickness direction X, the first sub-protrusion 421 has a minimum dimension B mm between it and the first surface 410, and the concave portion 420 has a minimum dimension C mm between it and the first surface 410, satisfying: 0.05 ≤ BC ≤ 0.1. It can be understood that the difference between the minimum dimension B between the first sub-protrusion 421 and the first surface 410 and the minimum dimension C between the concave portion 420 and the first surface 410 is the height difference between the highest point of the first sub-protrusion 421 and the lowest point of the concave portion 420. When the difference between the minimum dimension B between the first sub-protrusion 421 and the first surface 410 and the minimum dimension C between the concave portion 420 and the first surface 410 is relatively large, the height of the first sub-protrusion 421 is too large, and there is a problem of abnormal deformation and cracking of the explosion-proof valve 4 during the single-cell manufacturing process. When the difference between the minimum dimension B between the first sub-protrusion 421 and the first surface 410 and the minimum dimension C between the concave portion 420 and the first surface 410 is relatively small, the height of the first sub-protrusion 421 is too small, leading to abnormal deformation and cracking of the explosion-proof valve 4 during the single-cell manufacturing process. This application balances the structures of the first sub-protrusion 421 and the concave portion 420 by limiting the difference between the minimum dimension B between the first sub-protrusion 421 and the first surface 410 and the minimum dimension C between the concave portion 420 and the first surface 410. This allows them to better cope with internal pressure changes during single-cell manufacturing, preventing deformation and damage to the explosion-proof valve 4 due to structural inconsistencies, thereby ensuring the safety and reliability of the single-cell battery.

[0045] exist Figure 7In the illustrated embodiment, the support portion 40 has a maximum dimension A mm in the thickness direction X, satisfying: 0.4 ≤ A ≤ 0.6. Exemplarily, the maximum dimension A of the support portion 40 can be any value from 0.4, 0.42, 0.44, 0.46, 0.48, 0.5, 0.52, 0.54, 0.56, 0.58, and 0.6, or a range between any two. This configuration ensures the stability of the connection between the support portion 40 and the cover plate 3, preventing the explosion-proof valve 4 from loosening or falling off due to unstable connection during the single-cell manufacturing process or normal use, thus improving the safety and reliability of the single-cell battery.

[0046] exist Figure 7 In the illustrated embodiment, the support portion 40 has a maximum dimension A mm in the thickness direction X, and the recess 420 has a minimum dimension C mm between it and the first surface 410, satisfying A < C. By limiting the minimum dimension C between the recess 420 and the first surface 410 to be greater than the maximum dimension A of the support portion 40 in the thickness direction X, it can be ensured that the concave height of the recess 420 is within a reasonable range, avoiding the concave problem of the explosion-proof valve 4, thereby preventing the explosion-proof valve 4 from cracking or prematurely opening. This can effectively improve the production yield of the single battery and enhance the safety and reliability of the single battery.

[0047] In the embodiments of this application, explosion-proof valves 4 of different sizes (A, B, C, and D) are set and welded to the cover plate 3 for actual testing and verification. The abnormality of the explosion-proof valves 4 during the single cell manufacturing process is tracked, and the verification results are shown in Table 1.

[0048] Table 1:

[0049]

[0050]

[0051] Referring to Examples 1 to 9 in Table 1, when the single cell meets the following conditions: 0.3≤DC≤0.6, 0.05≤BC≤0.15, A<C, 0.4≤A≤0.6, and 0.7≤D≤1.2, there are no issues with deformation or abnormal cracking of the explosion-proof valve 4, such as concavity or convexity, during the single cell manufacturing process. It can be understood that by limiting the dimensions of the protrusion 42 and the concave portion 420 in the thickness direction X, it can be ensured that the explosion-proof valve 4 can absorb and disperse the stress caused by the pressure difference between the cavity 10 and the shell 1 during the single cell production process. This avoids the explosion-proof valve 4 from undergoing concavity or convexity deformation due to stress concentration, which could lead to cracking or premature opening of the explosion-proof valve 4. Therefore, it can effectively improve the production yield of the single cell and enhance its safety and reliability.

[0052] Referring to Comparative Example 1 in Table 1, with DC = 0.3 and BC = 0.04, the single cell meets the requirements of 0.3 ≤ DC ≤ 0.6, A < C, 0.4 ≤ A ≤ 0.6, and 0.7 ≤ D ≤ 1.2. However, BC is less than 0.04, failing to meet the requirement of 0.05 ≤ BC ≤ 0.15. The verification result is that the height of the first sub-protrusion 421 is too small, and the single cell manufacturing process exhibits abnormal deformation and cracking of the inner concave part of the explosion-proof valve 4. It is understandable that due to the small difference in BC, the distance between the first sub-protrusion 421 and the concave part 420 in the thickness direction X is too close, resulting in a smaller height for the first sub-protrusion 421. This causes the concave surface curvature of the concave part 420 to be too high, resulting in insufficient concave area. Consequently, the explosion-proof valve 4 cannot effectively absorb and disperse internal pressure during the single cell manufacturing process, leading to abnormal deformation and even cracking of the inner concave part.

[0053] Referring to Comparative Example 2 in Table 1, DC = 0.33, BC = 0.16. The single cell meets the requirements of 0.3 ≤ DC ≤ 0.6, A < C, 0.4 ≤ A ≤ 0.6, and 0.7 ≤ D ≤ 1.2. However, BC is greater than 0.15, failing to meet the requirement of 0.05 ≤ BC ≤ 0.15. The verification result is that the height of the first sub-protrusion 421 is too large, and the single cell manufacturing process has a problem of abnormal deformation and cracking of the explosion-proof valve 4. It is understandable that because the value of BC is large, the distance between the first sub-protrusion 421 and the concave part 420 in the thickness direction X is too large, resulting in the excessive height of the first sub-protrusion 421. In the single cell manufacturing process, an excessively high convex surface may cause the explosion-proof valve 4 to be easily damaged when subjected to abnormal pressure and deformation, leading to abnormal deformation and cracking.

[0054] Referring to Comparative Example 3 in Table 1, DC = 0.32, BC = 0.17. The single cell meets the requirements of 0.3 ≤ DC ≤ 0.6, A < C, 0.4 ≤ A ≤ 0.6, and 0.7 ≤ D ≤ 1.2. However, BC is greater than 0.15, failing to meet the requirement of 0.05 ≤ BC ≤ 0.15. The verification result is that the height of the first sub-protrusion 421 is too large, and the single cell manufacturing process has a problem of abnormal deformation and cracking of the explosion-proof valve 4. It is understandable that because the value of BC is large, the distance between the first sub-protrusion 421 and the concave part 420 in the thickness direction X is too large, resulting in the excessive height of the first sub-protrusion 421. In the single cell manufacturing process, an excessively high convex surface may cause the explosion-proof valve 4 to be easily damaged when subjected to abnormal pressure and deformation, leading to abnormal deformation and cracking.

[0055] Referring to Comparative Example 4 in Table 1, with DC = 0.29 and BC = 0.14, the single cell meets the requirements of 0.05 ≤ BC ≤ 0.15, A < C, 0.4 ≤ A ≤ 0.6, and 0.7 ≤ D ≤ 1.2. However, DC is less than 0.3, failing to meet the requirement of 0.3 ≤ DC ≤ 0.6. The verification result is that the concave surface curvature of recess 420 is too high, and the concave area is insufficient. This indicates an abnormal deformation and cracking problem in the concave area of ​​the explosion-proof valve 4 during the single cell manufacturing process. It is understandable that because the DC value is relatively small, the difference in thickness direction X between the protrusion 42 and the concave 420 is small, resulting in a high concave surface curvature and insufficient concave area in recess 420. This prevents the explosion-proof valve 4 from effectively absorbing and dispersing internal pressure during the single cell manufacturing process, leading to abnormal concave deformation and even cracking.

[0056] Referring to Comparative Example 5 in Table 1, with DC = 0.61 and BC = 0.1, the single cell meets the requirements of 0.05 ≤ BC ≤ 0.15, A < C, 0.4 ≤ A ≤ 0.6, and 0.7 ≤ D ≤ 1.2. However, DC is greater than 0.6, failing to meet the requirement of 0.3 ≤ DC ≤ 0.6. The verification result is that the height of the second sub-protrusion 422 is too large, leading to abnormal pressure damage to the explosion-proof valve 4 during the single cell manufacturing process. It is understandable that due to the large DC value, the difference in thickness direction X between the protrusion 42 and the recess 420 is too large, resulting in the excessive height of the second sub-protrusion 422. During the single cell manufacturing process, an excessively high protrusion may cause the explosion-proof valve 4 to be easily damaged when subjected to abnormal pressure and deformation.

[0057] Referring to Comparative Example 6 in Table 1, with DC = 0.55 and BC = 0.1, the individual cell meets the requirements of 0.3 ≤ DC ≤ 0.6, 0.05 ≤ BC ≤ 0.15, 0.4 ≤ A ≤ 0.6, and 0.7 ≤ D ≤ 1.2, but does not meet the requirement of A < C. The verification result shows that the concave surface of recess 420 is too low, leading to frequent concavity issues in the explosion-proof valve 4 during the vacuuming process in the individual cell manufacturing process. It is understandable that because the condition A ≥ C is not met, the overall structure of the explosion-proof valve 4 is affected, resulting in a low concave surface of recess 420. During the vacuuming process in the individual cell manufacturing process, the explosion-proof valve 4 cannot effectively cope with internal pressure changes, easily leading to concavity problems.

[0058] Referring to Comparative Example 7 in Table 1, DC = 0.53, BC = 0.08. The single cell meets the requirements of 0.3 ≤ DC ≤ 0.6, 0.05 ≤ BC ≤ 0.15, 0.4 ≤ A ≤ 0.6, and 0.7 ≤ D ≤ 1.2, but does not meet the requirement of A < C. The verification result shows that the concave surface of recess 420 is too low. During the vacuuming process in the single cell manufacturing process, the explosion-proof valve 4 frequently exhibits concave problems. It is understandable that because the condition A ≥ C is not met, it affects the overall structure of the explosion-proof valve 4, resulting in the concave surface of recess 420 being too low. During the vacuuming process in the single cell manufacturing process, the explosion-proof valve 4 cannot effectively cope with internal pressure changes, and is prone to concave problems.

[0059] In some embodiments, a notch 411 is provided in the weak portion 41, and the notch 411 surrounds the protrusion 42. By providing the notch 411, the weak portion 41 can more accurately rupture at the notch 411 when subjected to a preset pressure, ensuring that the explosion-proof valve 4 releases the gas inside the single cell in a timely manner under appropriate pressure, thereby effectively reducing the internal pressure and preventing the single cell from becoming dangerous.

[0060] In some embodiments, the notch 411 may be provided on the side of the weak portion 41 away from the electrode assembly 2 and recessed towards the electrode assembly 2. In other embodiments, the notch 411 may be provided on the side of the weak portion 41 close to the electrode assembly 2 and recessed away from the electrode assembly 2. Specifically, in Figure 3 , Figure 5 and Figure 7 In the illustrated embodiment, the groove 411 is provided on the side of the weak portion 41 away from the electrode assembly 2 and recessed towards the electrode assembly 2. The groove 411 can be formed by laser etching or by machining or other methods, and this application does not limit this.

[0061] exist Figure 2 and Figure 7 In the illustrated embodiment, the support portion 40 is connected to the side of the cover plate 3 near the electrode assembly 2, and the protrusion 42 protrudes into the explosion-proof hole 30. Placing the explosion-proof valve 4 on the side of the cover plate 3 near the electrode assembly 2 avoids the problem of easy failure due to scratching that occurs when welding the explosion-proof valve 4 to the outer wall of the cover plate 3, thus ensuring the stability of the connection between the explosion-proof valve 4 and the cover plate 3.

[0062] exist Figure 2 and Figure 7In the illustrated embodiment, a limiting groove 31 is formed on the side of the cover plate 3 near the electrode assembly 2. The limiting groove 31 surrounds the explosion-proof hole 30 and is formed on the side of the cover plate 3 near the electrode assembly 2. The supporting part 40 is disposed within the limiting groove 31. The limiting groove 31 can position and fix the explosion-proof valve 4. By providing the limiting groove 31 on the cover plate 3 and placing the explosion-proof valve 4 within the limiting groove 31, the explosion-proof valve 4 will not occupy the space of the electrode assembly 2 in the receiving cavity 10, thereby improving the energy density and performance of the single battery cell.

[0063] exist Figure 7 In the illustrated embodiment, along the thickness direction X of the cover plate 3, the bottom wall 310 of the limiting groove 31 and the side of the cover plate 3 near the electrode assembly 2 have a minimum dimension E mm, and the supporting part 40 has a maximum dimension A mm, satisfying: E ​​≥ A. It can be understood that by limiting the minimum dimension E between the bottom wall 310 of the limiting groove 31 and the side of the cover plate 3 near the electrode assembly 2 to be greater than or equal to the maximum dimension A of the supporting part 40, the explosion-proof valve 4 can be prevented from protruding from the lower surface of the cover plate 3, thereby preventing the explosion-proof valve 4 from occupying the space of the electrode assembly 2 in the receiving cavity 10, thus improving the energy density and performance of the single battery. Furthermore, it can also prevent the explosion-proof valve 4 from colliding or scratching with other components under vibration conditions, reducing the possibility of the single battery being endangered due to damage to the explosion-proof valve 4.

[0064] In some embodiments, there are multiple recesses 420 arranged on the protrusion 42, with one of two adjacent recesses 420 surrounding the other. In some embodiments, the multiple recesses 420 may be connected to each other. In other embodiments, the multiple recesses 420 may be spaced apart on the protrusion 42.

[0065] In some embodiments, the area of ​​the protrusion 42 is S1 mm. 2 The area of ​​explosion-proof valve 4 is S2 mm. 2The following condition must be met: 0.8 ≤ S1 / S2 ≤ 0.85. When the ratio of the area S1 of the protrusion 42 to the area S2 of the explosion-proof valve 4 is too large, it is understandable that the area occupied by the protrusion 42 in the explosion-proof valve 4 is too large, thus encroaching on the space of the weak part 41. This may cause the weak part 41 to fail to be properly destroyed when subjected to a preset pressure, affecting the function of the explosion-proof valve 4 in releasing internal gas. When the ratio of the area S1 of the protrusion 42 to the area S2 of the explosion-proof valve 4 is too small, the area of ​​the protrusion 42 is too small, and it cannot fully absorb and disperse the pressure difference stress from the production process of the single cell. This may easily cause the weak part 41 to crack due to stress concentration or cause the explosion-proof valve 4 to open prematurely, reducing the safety and reliability of the single cell. By limiting the range of the ratio of the area S1 of the protrusion 42 to the area S2 of the explosion-proof valve 4, the area of ​​the protrusion 42 and the area of ​​the explosion-proof valve 4 can be controlled within a certain ratio range, ensuring that the protrusion 42 achieves a more ideal state when playing its role in absorbing and dispersing stress. The design ensures that the protrusion 42 is neither too small to effectively distribute stress nor too large to impair the pressure relief function of the explosion-proof valve 4. This optimal area ratio allows the explosion-proof valve 4 to quickly release internal gas and reduce internal pressure when the internal pressure of a single battery cell is excessive, thereby improving the safety and reliability of the battery cell.

[0066] This application provides a battery pack including the aforementioned individual battery cells. Therefore, the battery pack can possess all the technical features and beneficial effects of the aforementioned individual battery cells, which will not be repeated here. The battery pack also includes a housing, wherein at least one individual battery cell is housed inside the housing.

[0067] Accordingly, this application also provides an electrical device, including the aforementioned single battery cell, or the aforementioned battery pack. Therefore, the electrical device can possess all the technical features and beneficial effects of the aforementioned single battery cell or battery pack, which will not be elaborated upon here. The electrical device can be a mobile phone, portable device, laptop computer, electric vehicle, electric car, ship, spacecraft, electric toy, and power tool, etc. For example, spacecraft include airplanes, rockets, space shuttles, and spacecraft; electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys; power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc.

[0068] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0069] The foregoing has provided a detailed description of a single battery, battery pack, and power device provided in the embodiments of this application, and specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the technical solutions and core ideas of this application. Those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A single-cell battery, characterized in that, include: A housing having a receiving cavity; An electrode assembly located within the receiving cavity; A cover plate, which is connected to the housing and seals the receiving cavity, and the cover plate is provided with explosion-proof holes; An explosion-proof valve, wherein the explosion-proof valve cover seals the explosion-proof orifice, the explosion-proof valve includes a support portion, a weak portion, and a protruding portion, the support portion is connected to the weak portion around the weak portion, the weak portion is connected to the protruding portion around the protruding portion, the support portion is connected to the cover plate, the weak portion is configured to be destroyed when subjected to a preset pressure impact, the protruding portion protrudes from the connection point with the weak portion toward the side away from the electrode assembly, the protruding portion is provided with a recessed portion toward the side closer to the electrode assembly; the protruding portion includes a first sub-protruding portion and a second sub-protruding portion, the first sub-protruding portion is disposed around the second sub-protruding portion, the recessed portion is disposed between the first sub-protruding portion and the second sub-protruding portion and is respectively connected to the first sub-protruding portion and the second sub-protruding portion; The weak portion includes a first surface of the cover plate near the electrode assembly in the thickness direction. The supporting portion has a maximum dimension A mm in the thickness direction. The first sub-protrusion has a minimum dimension B mm between itself and the first surface in the thickness direction. The concave portion has a minimum dimension C mm between itself and the first surface in the thickness direction. The protruding portion has a maximum dimension D mm between itself and the first surface, satisfying: A < C, 0.4 ≤ A ≤ 0.6, 0.05 ≤ BC ≤ 0.15, 0.3 ≤ DC ≤ 0.6, 0.7 ≤ D ≤ 1.

2.

2. The single-cell battery according to claim 1, characterized in that, The supporting part is connected to the side of the cover plate near the electrode assembly, and the protrusion protrudes into the explosion-proof hole.

3. The single-cell battery according to claim 1 or 2, characterized in that, A limiting groove is formed on the side of the cover plate near the electrode assembly. The limiting groove surrounds the explosion-proof hole. The limiting groove is formed on the side of the cover plate near the electrode assembly. The supporting part is disposed in the limiting groove.

4. The single-cell battery according to claim 3, characterized in that, Along the thickness direction, the bottom wall of the limiting groove and the side of the cover plate near the electrode assembly have a minimum dimension E mm, and the bearing part has a maximum dimension A mm, satisfying: E≥A.

5. A battery pack, characterized in that, Includes the single-cell battery as described in any one of claims 1 to 4.

6. An electrical device, characterized in that, It includes a single battery cell as described in any one of claims 1 to 4, or it includes a battery pack as described in claim 5.

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