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. The battery includes a housing and a cover plate connected to the housing. An explosion-proof valve covers an explosion-proof hole. The explosion-proof valve includes a support portion, a weak portion, and a protrusion. The support portion is connected to the weak portion around the weak portion, and the weak portion is connected to the protrusion. The support portion is connected to the cover plate. The protrusion protrudes towards the side away from the electrode assembly and has a recessed portion towards the side closer to the electrode assembly. The weak portion includes a first surface of the cover plate near the electrode assembly in the thickness direction. The protrusion has a maximum dimension D mm in the thickness direction between itself and the first surface. The protrusion has a first dimension W3 mm in the width direction Y of the cover plate, satisfying: 5.5 ≤ W3 / D ≤ 8.0. By limiting the proportional range of the protrusion's dimensions in the thickness direction and the width direction Y, it is ensured that the protrusion can effectively absorb and disperse stress, avoiding problems such as deformation cracking or premature valve opening of the explosion-proof valve.

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 a first surface of the cover plate close to the electrode assembly in the thickness direction. In the thickness direction, the protrusion has a maximum dimension D mm between itself and the first surface. In the width direction of the cover plate, the protrusion has a first dimension W3 mm, satisfying: 5.5≤W3 / D≤8.0. The width direction intersects the thickness direction.

[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, the first sub-protrusion has a maximum dimension B mm between itself and the first surface in the thickness direction, and the second sub-protrusion has a second dimension W1 mm ​​in the width direction, satisfying:

[0012] 5.0≤W1 / (DB)≤8.5.

[0013] In some embodiments, in the thickness direction, the first sub-protrusion has a maximum dimension B mm between itself and the first surface, and the concave portion has a minimum dimension C mm between itself and the first surface. In the width direction, the concave portion has a third dimension W2 mm, satisfying: 3.0 ≤ W2 / (BC) ≤ 6.0.

[0014] In some embodiments, the bearing portion has a maximum dimension A mm in the thickness direction, satisfying: 0.4 ≤ A ≤ 0.6.

[0015] 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.

[0016] 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.

[0017] In some embodiments, along the thickness direction, the bearing portion has a maximum dimension A mm, and the bottom wall of the limiting groove and the side of the cover plate near the electrode assembly have a minimum dimension E mm, satisfying: E≥A.

[0018] Accordingly, this application provides a battery pack including the aforementioned single battery cell.

[0019] Accordingly, embodiments of this application provide an electrical device, including the aforementioned single battery cell, or including the aforementioned battery pack.

[0020] 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 support portion, a weak portion, and a protrusion. The support portion is connected around the weak portion, and the weak portion is connected around the protrusion. 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 protrusion protrudes from the connection point with the weak portion toward the side away from the electrode assembly, and the protrusion has a recess that is recessed toward the side closer to the electrode assembly. The weak portion includes a first surface of the cover plate in the thickness direction close to the electrode assembly. In the thickness direction, the protrusion has a maximum dimension D mm between itself and the first surface. In the width direction of the cover plate, the protrusion has a first dimension W3 mm, satisfying: 5.5 ≤ W3 / D ≤ 8.0. The width direction intersects the thickness direction. By setting protrusions and recesses and further defining the ratio range between the first dimension W3 of the protrusion in the width direction and the maximum dimension D of the protrusion and the first surface in the thickness direction, it can be ensured that the protrusion can absorb and disperse the stress brought to the explosion-proof valve by the pressure difference between the cavity and the outside of the casing 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.

[0021] 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.

[0022] 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

[0023] 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.

[0024] Figure 1 This is an exploded view of a single battery cell according to an embodiment of this application;

[0025] Figure 2 This is a cross-sectional view of a cover plate according to an embodiment of this application;

[0026] Figure 3 This is a top view of an explosion-proof valve according to an embodiment of this application;

[0027] Figure 4 This is a bottom view of an explosion-proof valve according to an embodiment of this application;

[0028] Figure 5 This is a top view of an explosion-proof valve according to another embodiment of this application;

[0029] Figure 6 This is a bottom view of an explosion-proof valve according to another embodiment of this application;

[0030] Figure 7 This is a cross-sectional view of an explosion-proof valve according to an embodiment of this application;

[0031] Figure 8 This is a cross-sectional view of an explosion-proof valve according to another embodiment of this application.

[0032] 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; Y, Width direction. Detailed Implementation

[0033] 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.

[0034] 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.

[0035] 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.

[0036] In view of this, embodiments of this application provide a single battery, a battery pack, and an electrical device, including 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 in the thickness direction close to the electrode assembly. In the thickness direction, the protruding part has a maximum dimension D mm between itself and the first surface. In the width direction of the cover plate, the protruding part has a first dimension W3 mm, satisfying: 5.5≤W3 / D≤8.0, and the width direction intersects the thickness direction. By setting protrusions and recesses and further defining the ratio range between the first dimension W3 of the protrusion in the width direction and the maximum dimension D of the protrusion and the first surface of the weak part in the thickness direction, it can be ensured that the protrusion 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 the single cell. This avoids the explosion-proof valve from deforming due to stress concentration, which could lead to cracking or premature opening of the explosion-proof valve. As a result, the production yield of the single cell can be effectively improved, as well as the safety and reliability of the single cell.

[0037] 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.

[0038] 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.

[0039] 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 7This is a cross-sectional view of an explosion-proof valve 4 according to an embodiment of this application; Figure 8 This is a cross-sectional view of an explosion-proof valve according to another embodiment of this application.

[0040] refer to Figures 1 to 8 This 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 is provided with a recess 420 that is 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 in the thickness direction X, which is close to the electrode assembly 2. In the thickness direction X, the protrusion 42 has a maximum dimension D mm between itself and the first surface 410. In the width direction Y of the cover plate 3, the protrusion 42 has a first dimension W3 mm, satisfying: 5.5 ≤ W3 / D ≤ 8.0. The width direction Y intersects the thickness direction X. By setting the protrusion 42 and the recess 420, and further limiting the ratio range of the first dimension W3 of the protrusion 42 in the width direction Y and the maximum dimension D of the protrusion 42 and the first surface 410 in the thickness direction X, it can be ensured that the protrusion 42 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, and avoid the problem that the weak part 41 will deform due to the pressure difference, which may lead to the cracking of the weak part 41 or the 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.

[0041] When the ratio of the first dimension W3 of the protrusion 42 in the width direction Y to the maximum dimension D of the protrusion 42 and the first surface 410 in the thickness direction X is too small, the dimension of the protrusion 42 in the width direction Y is relatively small, resulting in insufficient structural strength of the explosion-proof valve 4, which cannot effectively withstand the effects of internal pressure and external environment. Abnormal deformation and cracking are prone to occur during the manufacturing process of individual cells, affecting the safety and reliability of the individual cells.

[0042] When the ratio of the first dimension W3 of the protrusion 42 in the width direction Y to the maximum dimension D of the protrusion 42 and the first surface 410 in the thickness direction X is too large, on the one hand, the dimension of the protrusion 42 in the width direction Y is relatively large, thus encroaching on the space of the weak part 41. This may cause the weak part 41 to fail to be properly destroyed under preset pressure, affecting the function of the explosion-proof valve 4 in releasing internal gas. On the other hand, the maximum dimension D of the protrusion 42 and the first surface 410 in the thickness direction X is relatively small, resulting in insufficient structural strength of the explosion-proof valve 4, which cannot effectively withstand the effects of internal pressure and external environment. Abnormal deformation and cracking are prone to occur in the single cell manufacturing process, affecting the safety and reliability of the single cell.

[0043] By limiting the ratio range between the first dimension W3 of the protrusion 42 in the width direction Y and the maximum dimension D of the protrusion 42 and the first surface 410 in the thickness direction X, 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 of the explosion-proof valve 4 leading to crushing. This allows the explosion-proof valve 4 to better cope with changes in the internal pressure of the single battery and open the valve in time when subjected to preset pressure, preventing excessive internal pressure of the single battery from causing fire, deflagration and other situations, thus ensuring the safety and reliability of the single battery.

[0044] exist Figures 2 to 8 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 7 The 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.

[0045] exist Figure 8In the embodiment shown, the protrusion 42 and the first surface 410 have a maximum dimension D mm in the thickness direction X, which is the maximum dimension between the second sub-protrusion 422 and the first surface 410; in the thickness direction X, the first sub-protrusion 421 and the first surface 410 have a maximum dimension B mm; in the width direction Y, the second sub-protrusion 422 has a second dimension W1 mm, satisfying: 5.0≤W1 / (DB)≤8.5. When W1 / (DB) is relatively small, W1 is relatively small while DB is relatively large, indicating that the height of the second sub-protrusion 422 is too small. Due to the insufficient structural dimensions of the second sub-protrusion 422, the explosion-proof valve 4 cannot effectively disperse stress through the second sub-protrusion 422 when subjected to internal pressure, resulting in abnormal internal deformation or even cracking during the single-cell manufacturing process. When W1 / (DB) is relatively large, W1 is relatively large while DB is relatively small, indicating that the dimensions of the first sub-protrusion 421 and the second sub-protrusion 422 in the thickness direction X are large, resulting in abnormal external deformation and cracking of the explosion-proof valve 4 during the single-cell manufacturing process. This application limits the protruding dimensions of the first sub-protrusion 421 and the second sub-protrusion 422 to better cope with changes in internal and external pressure during the single-cell manufacturing process, avoiding deformation or abnormal cracking of the explosion-proof valve 4 due to internal or external deformation caused by unreasonable structure, thereby ensuring the safety and reliability of the single-cell battery.

[0046] exist Figure 8 In the illustrated embodiment, in the thickness direction X, the first sub-protrusion 421 has a maximum dimension B mm between itself and the first surface 410, and the recess 420 has a minimum dimension C mm between itself and the first surface 410. In the width direction Y, the recess 420 has a third dimension W2 mm, satisfying: 3.0 ≤ W2 / (BC) ≤ 6.0. When W2 / (BC) is relatively small, W2 is relatively small and BC is relatively large, indicating that the dimension of the recess 420 in the width direction Y is small, and the single-cell manufacturing process may have problems with abnormal internal deformation or even cracking. When W2 / (BC) is relatively large, W2 is relatively large and BC is relatively small, indicating that the height of the first sub-protrusion 421 is relatively large. In the single-cell manufacturing process, an excessively high external convex surface may cause the explosion-proof valve 4 to be easily damaged when it is subjected to abnormal pressure and deformed. This application limits the dimensions of the recess 420, the first sub-protrusion 421, and the second sub-protrusion 422 to better cope with internal and external pressure changes during the manufacturing process of a single cell, and avoids deformation or abnormal cracking of the explosion-proof valve 4 due to unreasonable structure, thereby ensuring the safety and reliability of the single cell.

[0047] In the embodiments of this application, explosion-proof valves 4 of different sizes (B, C, D, W1, W2, W3) are provided 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, the individual cells meet the requirements of 5.0≤W1 / (DB)≤8.5, 3.0≤W2 / (BC)≤6.0, and 5.5≤W3 / D≤8.0. The verification results show that the individual cell manufacturing process does not exhibit deformation or abnormal cracking issues such as concavity or convexity of the explosion-proof valve 4. It is understood that this application, through reasonable design of the dimensions of the first sub-convex portion 421, the second sub-convex portion 422, and the concave portion 420, can effectively balance the structural strength, elastic deformation capability, and stress dispersion effect of the explosion-proof valve 4. This avoids the concavity or convexity of the explosion-proof valve 4 caused by unreasonable heights of the first sub-convex portion 421 and the second sub-convex portion 422, preventing deformation or abnormal cracking of the explosion-proof valve 4 during the individual cell manufacturing process, thus ensuring the safety and reliability of the individual cells.

[0052] Referring to Comparative Example 1 in Table 1, W1 / (DB) = 4.9, W2 / (BC) = 5.5, and W3 / D = 5.63. The individual cells meet the requirements of 3.0 ≤ W2 / (BC) ≤ 6.0 and 5.5 ≤ W3 / D ≤ 8.0, but W1 / (DB) is less than 5.0, failing to meet the requirement of 5.0 ≤ W1 / (DB) ≤ 8.5. This verification indicates that the height of the second sub-protrusion 422 is too small, resulting in an abnormal concave deformation during the individual cell manufacturing process. It is understandable that when W1 / (DB) is relatively small, W1 is relatively small, while DB is relatively large, indicating that the height of the second sub-protrusion 422 is too small. Due to the insufficient structural dimensions of the second sub-protrusion 422, the explosion-proof valve 4 cannot effectively disperse stress through the second sub-protrusion 422 when subjected to internal pressure, leading to abnormal concave deformation and even cracking during the individual cell manufacturing process.

[0053] Referring to Comparative Example 2 in Table 1, W1 / (DB) = 8.67, W2 / (BC) = 3.24, and W3 / D = 5.63. The individual cells meet the requirements of 3.0 ≤ W2 / (BC) ≤ 6.0 and 5.5 ≤ W3 / D ≤ 8.0, but W1 / (DB) is greater than 8.5, failing to meet the requirement of 5.0 ≤ W1 / (DB) ≤ 8.5. This verifies that the individual cell manufacturing process exhibits abnormal deformation and cracking of the explosion-proof valve 4 due to outward bulging. It is understandable that when W1 / (DB) is relatively large, W1 is relatively large while DB is relatively small, indicating that the dimensions of the first sub-protrusion 421 and the second sub-protrusion 422 are large in the thickness direction X, suggesting an abnormal deformation and cracking problem of the explosion-proof valve 4 in the individual cell manufacturing process.

[0054] Referring to Comparative Example 3 in Table 1, W1 / (DB) = 6.5, W2 / (BC) = 2.9, and W3 / D = 5.29. The individual cells meet the requirements of 5.0 ≤ W1 / (DB) ≤ 8.5 and 5.5 ≤ W3 / D ≤ 8.0. However, W2 / (BC) is less than 3.0, failing to meet the requirement of 3.0 ≤ W2 / (BC) ≤ 6.0. This verifies that the individual cell manufacturing process has an abnormal concave issue with the explosion-proof valve 4. It is understandable that when W2 / (BC) is relatively small, W2 is relatively small, and BC is relatively large, indicating that the dimension of the concave portion 420 in the width direction Y is small, suggesting an abnormal concave deformation or even cracking problem in the individual cell manufacturing process.

[0055] Referring to Comparative Example 4 in Table 1, W1 / (DB) = 5.65, W2 / (BC) = 6.11, and W3 / D = 5.11. The individual cell meets the requirements of 5.0 ≤ W1 / (DB) ≤ 8.5 and 5.5 ≤ W3 / D ≤ 8.0. However, W2 / (BC) is greater than 6.0, failing to meet the requirement of 3.0 ≤ W2 / (BC) ≤ 6.0. This verifies that the individual cell manufacturing process has an abnormal deformation and cracking problem with the explosion-proof valve 4. It is understandable that the relatively large W2 and relatively small BC indicate that the height of the first sub-protrusion 421 is relatively large. In the individual 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.

[0056] Referring to Comparative Example 5 in Table 1, W1 / (DB) = 5.2, W2 / (BC) = 4.58, and W3 / D = 5.44. The individual cell meets the requirements of 5.0 ≤ W1 / (DB) ≤ 8.5 and 3.0 ≤ W2 / (BC) ≤ 6.0, but W3 / D is less than 5.5, failing to meet the requirement of 5.5 ≤ W3 / D ≤ 8.0. This verifies that the explosion-proof valve 4 exhibits abnormal deformation and cracking during the individual cell manufacturing process. It is understandable that when W3 / D is relatively small, the protrusion 42 has a relatively small dimension in the width direction Y, resulting in insufficient structural strength of the explosion-proof valve 4, making it unable to effectively withstand internal pressure and external environmental forces. This can easily lead to abnormal deformation and cracking during the individual cell manufacturing process, affecting the safety and reliability of the individual cell.

[0057] Referring to Comparative Example 6 in Table 1, W1 / (DB) = 5.2, W2 / (BC) = 4.58, and W3 / D = 8.11. The individual battery cell meets the requirements of 5.0 ≤ W1 / (DB) ≤ 8.5 and 3.0 ≤ W2 / (BC) ≤ 6.0, but W3 / D is greater than 8.0, failing to meet the requirement of 5.5 ≤ W3 / D ≤ 8.0. This verifies that the individual battery cell manufacturing process exhibits abnormal deformation and cracking of the explosion-proof valve 4. It is understandable that when W3 / D is relatively large, on the one hand, the protrusion 42 has a relatively large dimension in the width direction Y, thus encroaching on the space of the weak part 41. This may prevent the weak part 41 from being properly destroyed under preset pressure, affecting the function of the explosion-proof valve 4 in releasing internal gas. On the other hand, the maximum dimension D between the protrusion 42 and the first surface 410 in the thickness direction X is relatively small, resulting in insufficient structural strength of the explosion-proof valve 4, making it unable to effectively withstand internal pressure and the effects of the external environment. Abnormal deformation and cracking can easily occur during the manufacturing process of individual cells, affecting the safety and reliability of individual cells.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] exist Figure 8 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 cover plate 3 have a minimum dimension E mm, and the supporting part 40 has a maximum dimension A mm, satisfying: E ​​≥ A, 0.4 ≤ A ≤ 0.6. Exemplarily, the maximum dimension A of the supporting part 40 can be any one of 0.4, 0.42, 0.44, 0.46, 0.48, 0.5, 0.52, 0.54, 0.56, 0.58, 0.6, or a range between any two. It is 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 cell. Furthermore, it can also prevent the explosion-proof valve 4 from colliding or scraping with other components under vibration conditions, reducing the possibility of damage to the explosion-proof valve 4 causing danger to the individual battery.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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: The housing (1) has a receiving cavity (10); Electrode assembly (2), the electrode assembly (2) being located within the receiving cavity (10); Cover plate (3), the cover plate (3) is connected to the housing (1) and covers the receiving cavity (10), the cover plate (3) is provided with explosion-proof hole (30); An explosion-proof valve (4) is provided, which covers the explosion-proof hole (30). The explosion-proof valve (4) includes a support part (40), a weak part (41) and a protrusion (42). The support part (40) is connected around the weak part (41), and the weak part (41) is connected around the protrusion (42). The support part (40) is connected to the cover plate (3). The weak part (41) is configured to be destroyed when subjected to a preset pressure impact. The protrusion (42) protrudes from the connection with the weak part (41) toward the side away from the electrode assembly (2). The protrusion (42) is provided with a recess (420) that is recessed toward the side close to the electrode assembly (2). The weak part (41) includes a first surface (410) of the cover plate (3) in the thickness direction (X) close to the electrode assembly (2). In the thickness direction (X), the protrusion (42) has a maximum dimension D mm between it and the first surface (410). In the width direction (Y) of the cover plate (3), the protrusion (42) has a first dimension W3 mm, satisfying: 5.5≤W3 / D≤8.

0. The width direction (Y) intersects the thickness direction (X). The protrusion (42) includes a first sub-protrusion (421) and a second sub-protrusion (422). The first sub-protrusion (421) is disposed around the second sub-protrusion (422). The recess (420) is disposed between the first sub-protrusion (421) and the second sub-protrusion (422) and is connected to the first sub-protrusion (421) and the second sub-protrusion (422) respectively. In the thickness direction (X), the first sub-protrusion (421) has a maximum dimension Bmm between it and the first surface (410), and in the width direction (Y), the second sub-protrusion (422) has a second dimension W1mm, satisfying: 5.0≤W1 / (DB)≤8.5; In the thickness direction (X), the first sub-protrusion (421) has a maximum 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). In the width direction (Y), the concave portion (420) has a third dimension W2 mm, satisfying: 3.0 ≤ W2 / (BC) ≤ 6.

0.

2. The single-cell battery according to claim 1, characterized in that, In the thickness direction (X), the bearing part (40) has a maximum dimension A mm, which satisfies: 0.4≤A≤0.

6.

3. The single-cell battery according to claim 1, characterized in that, The support portion (40) is connected to the cover plate (3) on the side near the electrode assembly (2), and the protrusion (42) protrudes into the explosion-proof hole (30).

4. The single-cell battery according to claim 1 or 3, characterized in that, The cover plate (3) has a limiting groove (31) on the side near the electrode assembly (2). The limiting groove (31) surrounds the explosion-proof hole (30). The limiting groove (31) is located on the side of the cover plate (3) near the electrode assembly (2). The bearing part (40) is located in the limiting groove (31).

5. The single-cell battery according to claim 4, characterized in that, Along the thickness direction (X), the bearing part (40) has a maximum size A mm, and 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 size E mm, satisfying: E≥A.

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

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

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