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 casing and a cover plate, with an explosion-proof valve cover sealing the explosion-proof hole of the cover plate. 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 its connection with the weak portion towards the side away from the electrode assembly. In the thickness direction of the cover plate, the maximum dimension of the cover plate is A mm, and the maximum dimension of the protrusion is C mm, satisfying: 0.4 ≤ C / A ≤ 0.7. By setting the protrusion to absorb and disperse the stress on the explosion-proof valve caused by the pressure difference between the cavity and the outside of the casing during the single-cell battery production process, and limiting the range of the ratio of the maximum dimension C of the protrusion to the maximum dimension A of the cover plate, the risk of abnormal cracking and premature valve opening of the explosion-proof valve can be reduced, while avoiding the problem of the protrusion of the explosion-proof valve being crushed and dented.

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 Technology

[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 load-bearing part, a weak part, and a protruding part. The load-bearing part is connected around the weak part, and the weak part is connected around the protruding part. The load-bearing part is connected to a 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.

[0009] In the thickness direction of the cover plate, the maximum dimension of the cover plate is A mm, and the maximum dimension of the protrusion is C mm, satisfying: 0.4≤C / A≤0.7.

[0010] In some embodiments, the single cell satisfies: 1.5≤A≤2.5, 0.8≤C≤2.0.

[0011] In some embodiments, the single cell satisfies: 1.5≤A≤2, 0.8≤C≤1.5.

[0012] In some embodiments, a single cell satisfies: 2 < A ≤ 2.5, 1.0 ≤ C ≤ 2.0.

[0013] In some embodiments, the thickness of the protrusion is t mm, satisfying: 0.15≤t≤0.3.

[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 and is provided on the side of the cover plate near the electrode assembly. The supporting part is provided in the limiting groove.

[0016] In some embodiments, along the thickness direction, the bearing portion has a maximum dimension B mm, and the bottom wall of the limiting groove and the side of the cover plate near the electrode assembly have a minimum dimension D mm, satisfying: D≥B, 0.4≤B≤0.6.

[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 within 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. In the thickness direction of the cover plate, the maximum dimension of the cover plate is A mm, and the maximum dimension of the protrusion is C mm, satisfying: 0.4 ≤ C / A ≤ 0.7. By providing the protrusion, the stress on the explosion-proof valve caused by the pressure difference between the receiving cavity and the outside of the casing during the single-cell battery production process is absorbed and dispersed. Furthermore, by limiting the range of the ratio between the maximum size C of the protrusion and the maximum size A of the cover plate, the risk of abnormal cracking and premature opening of the explosion-proof valve can be reduced, while avoiding the problem of the protrusion of the explosion-proof valve being crushed and dented. This can effectively improve the production yield of individual cells and enhance the safety and reliability of individual 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 4 This is a bottom view of an explosion-proof valve according to an embodiment of this application;

[0027] Figure 5 This is a cross-sectional view of an explosion-proof valve according to an embodiment of this application.

[0028] 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. Score; X, Thickness direction. Detailed Implementation

[0029] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0030] 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.

[0031] 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.

[0032] In view of this, embodiments of this application provide a single-cell 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 within 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 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, and the weak portion is configured to be destroyed when subjected to a preset pressure impact. The protrusion protrudes from its connection with the weak portion toward a side away from the electrode assembly. In the thickness direction of the cover plate, the maximum dimension of the cover plate is A mm, and the maximum dimension of the protrusion is C mm, satisfying: 0.4 ≤ C / A ≤ 0.7. The protrusion is provided to absorb and disperse the stress on the explosion-proof valve caused by the pressure difference between the receiving cavity and the outside of the housing during the single-cell battery production process. Furthermore, by limiting the range of the ratio between the maximum size C of the protrusion and the maximum size A of the cover plate, the risk of abnormal cracking and premature opening of the explosion-proof valve can be reduced, while avoiding the problem of the protrusion of the explosion-proof valve being crushed and dented. This can effectively improve the production yield of individual cells and enhance the safety and reliability of individual cells.

[0033] In this application, a single battery cell may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-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, 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.

[0034] 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.

[0035] 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 cross-sectional view of an explosion-proof valve 4 according to an embodiment of this application.

[0036] refer to Figures 1 to 5This 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, which is sealed by the explosion-proof valve 4. 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, and the weak part 41 is connected to the protruding 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. This design ensures the sealing requirements of the single-cell battery under normal use and also ensures smooth explosion under pressure, facilitating venting. 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 battery from exploding due to excessively rapid internal pressurization. The protrusion 42 protrudes from the connection point with the weak part 41 towards the side away from the electrode assembly 2. The protrusion 42 avoids stress concentration. By providing the protrusion 42, 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 the single cell can be absorbed and dispersed, preventing the weak part 41 from deforming due to the pressure difference, which could lead to cracking of the weak part 41 or premature opening of the explosion-proof valve 4. In the thickness direction X of the cover plate 3, the maximum dimension of the cover plate 3 is A mm, and the maximum dimension of the protrusion 42 is C mm, satisfying: 0.4≤C / A≤0.7.

[0037] It is understandable that if the ratio of the maximum dimension C of the protrusion 42 to the maximum dimension A of the cover plate is too small, during the processes of electrolyte injection, pre-charge formation, and capacity testing in the single-cell manufacturing process, when there is an alternating positive and negative pressure difference between the single-cell housing cavity and the outside, problems such as deformation and cracking of the weak part 41 or premature opening of the explosion-proof valve 4 may easily occur. If the ratio of the maximum dimension C of the protrusion 42 to the maximum dimension A of the cover plate is too large, the protrusion 42 is easily damaged and dented, affecting the normal function of the explosion-proof valve 4. By limiting the range of the ratio of the maximum dimension C of the protrusion 42 to the maximum dimension A of the cover plate, this embodiment of the application can reduce the risk of abnormal cracking and premature opening of the explosion-proof valve 4, while avoiding the problem of damage and denting of the protrusion 42 of the explosion-proof valve 4, thereby effectively improving the production yield of single cells and improving the safety and reliability of single cells.

[0038] exist Figure 5In the illustrated embodiment, the thickness of the protrusion 42 is t mm, satisfying: 0.15 ≤ t ≤ 0.3. Exemplarily, the thickness t of the protrusion 42 can be any one of 0.15, 0.16, 0.17, 0.18, 0.19, 0.2, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, or 0.3, or a range between any two. If the thickness t of the protrusion 42 is too small, the structural strength of the explosion-proof valve 4 may be reduced, failing to adequately disperse and absorb the stress caused by the internal and external pressure differences during the single-cell manufacturing process, increasing the risk of abnormal cracking and premature valve opening of the explosion-proof valve 4. If the thickness t of the protrusion 42 is too large, the overall weight of the explosion-proof valve 4 increases, potentially slowing its response speed to pressure changes, preventing timely valve opening, and increasing the risk of single-cell fire and explosion. By limiting the thickness t of the protrusion, the structural strength of the explosion-proof valve 4 can be ensured, and abnormal cracking and premature opening of the explosion-proof valve 4 can be avoided. At the same time, the performance of the explosion-proof valve 4 can be ensured so that the valve can open normally under the preset pressure in the receiving cavity 10, thereby improving the safety and reliability of the single battery.

[0039] In some embodiments, the support portion 40 has a maximum dimension B mm in the thickness direction X of the cover plate 3, satisfying: 0.4 ≤ B ≤ 0.6. Exemplarily, the maximum dimension B of the support portion 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, or 0.6, or a range between any two. This configuration ensures the connection stability 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, thereby improving the safety and reliability of the single-cell battery.

[0040] In some embodiments, the single cell satisfies: 1.5 ≤ A ≤ 2.5, 0.8 ≤ C ≤ 2.0. Exemplarily, the maximum dimension A of the cover plate can be any value from 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, or a range between any two. This configuration ensures that the cover plate 3 has sufficient strength to effectively seal the receiving cavity 10, guaranteeing the structural stability of the single cell. The maximum dimension C of the protrusion 42 can be any value from 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, or a range between any two. This configuration reduces the risk of abnormal cracking and premature opening of the explosion-proof valve 4, while preventing the protrusion 42 of the explosion-proof valve 4 from being damaged or dented, thereby effectively improving the production yield of the single cell and enhancing its safety and reliability.

[0041] In some embodiments, the single cell satisfies: 1.5≤A≤2, 0.8≤C≤1.5. In the embodiments of this application, the maximum dimension B of the support part 40 in the thickness direction X is designed to be 0.5, and the maximum dimension A of the cover plate 3 in the thickness direction X is between 1.5 and 2. Explosion-proof valves 4 with different dimensions C are provided and welded to the cover plate 3. By tracking and testing the scratch thickness of the explosion-proof valve 4 and the application process of the cover plate 3 on the production line, the influence of the C / A ratio on the residual thickness of the scratch of the explosion-proof valve 4 and the application on the production line under the same burst pressure is verified. The verification results are shown in Table 1.

[0042] Table 1:

[0043]

[0044] Referring to Examples 1 to 7 in Table 1, when the maximum dimension C of the protrusion 42 and the maximum dimension A of the cover plate simultaneously satisfy 1.5≤A≤2, 0.8≤C≤1.5, and 0.4≤C / A≤0.7, the average burst pressure is 0.9 MPa. At this time, the residual thickness of the groove 410 of the explosion-proof valve 4 is basically stable between 68.5 μm and 69.8 μm. The structural strength of the explosion-proof valve 4 is improved, which can reduce the risk of abnormal cracking and premature valve opening of the explosion-proof valve 4, and the problem of the protrusion 42 of the explosion-proof valve 4 being crushed and dented does not occur.

[0045] Referring to Comparative Examples 1 to 3 in Table 1, when the C / A ratio is less than 0.4, that is, when the maximum dimension C of the protrusion 42 is small, the residual thickness of the notch 410 of the explosion-proof valve 4 is between 60.1 μm and 64.4 μm. It is understandable that a small protrusion size of the protrusion 42 may prevent the absorption and dispersion of stress on the explosion-proof valve 4 caused by the pressure difference between the cavity 10 and the shell 1 during the production of the single-cell battery. This can lead to deformation of the weak part 41 due to the pressure difference, resulting in problems such as deformation and cracking of the weak part 41, or premature opening of the explosion-proof valve 4.

[0046] Referring to Comparative Examples 4 and 5 in Table 1, when the C / A ratio is greater than 0.7, that is, when the maximum size C of the protrusion 42 is too large, the residual thickness of the scratch 410 of the explosion-proof valve 4 does not change much. However, in the process of manufacturing a single cell, the protrusion 42 of the explosion-proof valve 4 is damaged and dented, which affects the yield and safety performance of the single cell process.

[0047] In some embodiments, the single cell satisfies: 2 < A ≤ 2.5, 1.0 ≤ C ≤ 2.0. In the embodiments of this application, by designing the maximum dimension B of the support part 40 in the thickness direction X to be 0.5, and the maximum dimension A of the cover plate 3 in the thickness direction X to be between 2 and 2.5, explosion-proof valves 4 with different dimensions C are set and welded to the cover plate 3. By tracking and testing the score thickness of the explosion-proof valve 4 and the application process of the cover plate 3 on the production line, the influence of the C / A ratio on the residual score thickness of the explosion-proof valve 4 and the application on the production line under the same burst pressure is verified. The verification results are shown in Table 2.

[0048] Table 2:

[0049]

[0050]

[0051] Referring to Examples 8 to 13 in Table 2, when the maximum dimension C of the protrusion 42 and the maximum dimension A of the cover plate simultaneously satisfy 2<A≤2.5, 0.8≤C≤2, and 0.4≤C / A≤0.7, the average burst pressure is 0.9 MPa. At this time, the residual thickness of the groove 410 of the explosion-proof valve 4 is basically stable between 68.8 μm and 70.5 μm. The structural strength of the explosion-proof valve 4 is improved, which can reduce the risk of abnormal cracking and premature valve opening of the explosion-proof valve 4, and the problem of the protrusion 42 of the explosion-proof valve 4 being crushed and dented does not occur.

[0052] Referring to Comparative Examples 6 and 7 in Table 2, when C / A is less than 0.4, that is, when the maximum dimension C of the protrusion 42 is small, the residual thickness of the notch 410 of the explosion-proof valve 4 is 63.3 μm and 65.8 μm, respectively. It is understandable that the small size of the protrusion 42 may lead to insufficient absorption and dispersion of 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 the single cell. This can cause the weak part 41 to deform due to the pressure difference, which may result in deformation and cracking of the weak part 41, or premature opening of the explosion-proof valve 4.

[0053] Referring to Comparative Examples 8 and 9 in Table 2, when C / A is greater than 0.7, that is, when the maximum size C of the protrusion 42 is too large, the residual thickness of the scratch 410 of the explosion-proof valve 4 does not change much as the maximum size C of the protrusion 42 increases. However, in the process of manufacturing a single cell, the protrusion 42 of the explosion-proof valve 4 is damaged and dented, which affects the yield and safety performance of the single cell process.

[0054] 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.

[0055] In some embodiments, a notch 410 is provided in the weak portion 41, and the notch 410 surrounds the protrusion 42. By providing the notch 410, the weak portion 41 can more accurately rupture at the notch 410 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. By forming an annular notch 410 in at least a portion of the weak portion, the local thinning of the annular notch 410 can provide a path guide for opening the weak portion 41, facilitating the opening of the explosion-proof valve along the path of the notch 410.

[0056] In some embodiments, the notch 410 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 410 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 and Figure 5 In the illustrated embodiment, the groove 410 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 410 can be formed by laser etching or by machining or other methods, and this application does not limit this.

[0057] exist Figure 2 and Figure 5In 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.

[0058] exist Figure 2 and Figure 5 In 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.

[0059] exist Figure 5 In the illustrated embodiment, along the thickness direction X of the cover plate 3, the supporting portion 40 has a maximum dimension B 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 dimension D mm, satisfying: D ≥ B, 0.4 ≤ B ≤ 0.6. Exemplarily, the maximum dimension B of the supporting portion 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 D 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 B of the supporting portion 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.

[0060] 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.

[0061] 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.

[0062] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0063] 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) has explosion-proof holes (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). In the thickness direction (X) of the cover plate (3), the maximum dimension of the cover plate (3) is A mm, and the maximum dimension of the protrusion (42) is C mm, satisfying: 0.4≤C / A≤0.7; 1.5≤A≤2.5, 0.8≤C≤2.

0.

2. The single-cell battery according to claim 1, characterized in that, The individual cell satisfies: 1.5≤A≤2, 0.8≤C≤1.

5.

3. The single-cell battery according to claim 1, characterized in that, The single cell satisfies: 2 < A ≤ 2.5, 1.0 ≤ C ≤ 2.

0.

4. The single-cell battery according to claim 1, characterized in that, The thickness of the protrusion (42) is t mm, which satisfies: 0.15≤t≤0.

3.

5. 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).

6. The single-cell battery according to claim 1 or 5, 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) and 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).

7. The single-cell battery according to claim 6, characterized in that, Along the thickness direction (X), the bearing part (40) has a maximum size B 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 D mm, satisfying: D≥B, 0.4≤B≤0.

6.

8. A battery pack, characterized in that, Includes the single-cell battery as described in any one of claims 1 to 7.

9. An electrical device, characterized in that, It includes a single cell battery as described in any one of claims 1 to 7, or it includes a battery pack as described in claim 8.

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