Single battery, battery pack and power utilization device

Abstract

The invention discloses a single battery, a battery pack and a power utilization device, and belongs to the technical field of batteries, the single battery comprises a shell and a cover plate connected with the shell, and the cover plate is provided with an anti-explosion hole; the anti-explosion valve covers the anti-explosion hole, the anti-explosion valve comprises a bearing part, a weak part and a protruding part, the bearing part is connected to the weak part in a surrounding mode, the weak part is connected to the protruding part in a surrounding mode, the bearing part is connected with the cover plate, the protruding part protrudes towards the side away from the electrode assembly, and a concave part which is concave towards the side close to the electrode assembly is arranged on the protruding part. The weak part comprises a first surface close to the electrode assembly in the thickness direction of the cover plate, in the thickness direction, the minimum size C mm is formed between the concave part and the first surface, the maximum size D mm is formed between the convex part and the first surface, and 0.3 < = D-C < = 0.6 is satisfied. By limiting the difference value range of the protruding part and the concave part in the thickness direction, it is ensured that the anti-explosion valve can effectively absorb and disperse stress, and the problem that the anti-explosion valve deforms and cracks or is opened in advance is avoided.

Description

Technical Field

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

[0002] Lithium-ion batteries are currently widely used in various fields such as transportation power supply, electric energy storage power supply, new energy storage power supply, aerospace and military industry due to their large capacity, high operating voltage, strong charge retention ability and long cycle life. The cover plate in the battery is usually integrated with poles, explosion-proof valves and other structures. Among them, the main function of the explosion-proof valve is to release pressure and exhaust. It is used for the directional release of internal high-temperature and high-pressure gas when the battery cell has thermal runaway due to mechanical impact, internal abnormal lap short circuit and other reasons, thereby improving the safety performance of the battery pack. However, in the processes of battery cell injection, pre-charging formation, and capacity division, there is a repeated positive and negative alternating pressure difference between the inside of the battery and the outside world, which causes deformation, cracking, premature opening of the explosion-proof valve and other problems, seriously affecting the battery process yield and safety performance. Summary of the invention

[0003] Purpose of the invention: The embodiments of the present application provide 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 the battery preparation process.

[0004] Technical solution: The present application embodiment provides a single battery, including:

[0005] A housing having a receiving cavity;

[0006] An electrode assembly, the electrode assembly is located in the accommodating cavity;

[0007] A cover plate, which is connected to the shell and covers the accommodating cavity, and is provided with an explosion-proof hole;

[0008] An explosion-proof valve, the explosion-proof valve cover seals the explosion-proof hole, the explosion-proof valve comprises a bearing portion, a weak portion and a protruding portion, the bearing portion is connected to the weak portion in a surrounding manner, the weak portion is connected to the protruding portion in a surrounding manner, the bearing 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 with the weak portion toward a side away from the electrode assembly, and a concave portion is provided on the protruding portion and is concave toward a side close to the electrode assembly;

[0009] The weak portion includes a first surface close to the electrode assembly in the thickness direction of the cover plate, and in the thickness direction, the concave portion and the first surface have a minimum dimension C mm, and the protruding portion and the first surface have a maximum dimension D mm, 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 is arranged around the second sub-protrusion, and the recess is arranged 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, there is a minimum dimension B mm between the first sub-protrusion and the first surface, satisfying: 0.05≤BC≤0.15.

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

[0013] In some embodiments, the single battery satisfies: 0.7≤D≤1.2.

[0014] In some embodiments, the bearing portion is connected to a side of the cover plate close to the electrode assembly, and the protruding portion protrudes into the explosion-proof hole.

[0015] In some embodiments, a limiting groove is opened on one side of the cover plate close to the electrode assembly, the limiting groove is arranged around the explosion-proof hole, the limiting groove is opened on one side of the cover plate close to the electrode assembly, and the bearing part is arranged in the limiting groove.

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

[0017] Accordingly, an embodiment of the present application provides a battery pack, comprising the above-mentioned single battery.

[0018] Correspondingly, an embodiment of the present application provides an electrical device, including the above-mentioned single battery, or including the above-mentioned battery pack.

[0019] Beneficial effects: The single cell of the embodiment of the present application includes a shell, an electrode assembly, a cover plate and an explosion-proof valve. The shell has a housing cavity; the electrode assembly is located in the housing cavity; the cover plate is connected to the shell and covers the housing cavity, and the cover plate is provided with an explosion-proof hole; the explosion-proof valve covers the explosion-proof hole, and the explosion-proof valve includes a bearing part, a weak part and a protruding part, the bearing part is connected around the weak part, the weak part is connected around the protruding part, the bearing part is connected to the cover plate, the weak part is configured to be destroyed when subjected to a preset pressure shock, the protruding part protrudes from the connection with the weak part toward a side away from the electrode assembly, and the protruding part is provided with a concave part that is concave toward a side close to the electrode assembly; wherein the weak part includes a first surface close to the electrode assembly in the thickness direction of the cover plate, in the thickness direction, there is a minimum dimension C mm between the concave part and the first surface, and there is a maximum dimension D mm between the protruding part and the first surface, satisfying: 0.3≤DC≤0.6. By providing the protrusion and the recess and further limiting the difference range of the protrusion and the recess in the thickness direction, it can be ensured that the explosion-proof valve can absorb and disperse the stress caused to the explosion-proof valve by the pressure difference inside the accommodating cavity and outside the shell during the production of the single cell, thereby avoiding deformation of the explosion-proof valve due to stress concentration, which may lead to cracking of the explosion-proof valve or premature opening of the valve, thereby effectively improving the production yield of the single cell and improving the safety and reliability of the single cell.

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

[0021] The electrical device of the embodiment of the present application includes the above-mentioned single cell or the above-mentioned battery pack, so the electrical device can have all the technical features and beneficial effects of the above-mentioned single cell or battery pack, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 is an exploded diagram of a single cell of an embodiment of the present application;

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

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

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

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

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

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

[0030] Figure numerals: 1, shell; 2, electrode assembly; 3, cover plate; 4, explosion-proof valve; 10, accommodating chamber; 30, explosion-proof hole; 31, limiting groove; 40, bearing part; 41, weak part; 42, protrusion; 310, bottom wall; 410, first surface; 411, notch; 420, recess; 421, first sub-protrusion; 422, second sub-protrusion; X, thickness direction. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0032] In the description of the present application, it should be understood that the terms "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more features. In the description of the present application, "multiple" means two or more, and at least one means one, two or more, unless otherwise clearly and specifically defined. In the description of this application, "vertical" means completely vertical at 90° or almost completely vertical, for example, an angle within the range of 80° to 100° is considered vertical. Similarly, "parallel" means completely parallel or almost completely parallel, for example, an angle within 10° of completely parallel is considered parallel.

[0033] The applicant noted that lithium-ion batteries are currently widely used in various fields such as transportation power supply, electric energy storage power supply, new energy storage power supply, aerospace and military industry due to their large capacity, high operating voltage, strong charge retention ability and long cycle life. The cover plate in the battery is usually integrated with poles, explosion-proof valves and other structures. Among them, the main function of the explosion-proof valve is to release pressure and exhaust. It is used for the directional release of internal high-temperature and high-pressure gas when the battery cell has thermal runaway due to mechanical impact, internal abnormal lap short circuit and other reasons, thereby improving the safety performance of the battery pack. However, in the processes of battery cell injection, pre-charging formation, and capacity division, there is a repeated positive and negative alternating pressure difference between the inside of the battery and the outside world, which causes deformation, cracking, premature opening of the explosion-proof valve and other problems, seriously affecting the battery process yield and safety performance.

[0034] In view of this, the embodiment of the present application provides a single cell, a battery pack and an electric device. The single cell of the embodiment of the present application includes a shell, an electrode assembly, a cover plate and an explosion-proof valve. The shell has a receiving cavity; the electrode assembly is located in the receiving cavity; the cover plate is connected to the shell and covers the receiving cavity, and the cover plate is provided with an explosion-proof hole; the explosion-proof valve covers the explosion-proof hole, and the explosion-proof valve includes a bearing part, a weak part and a protruding part, the bearing part is connected around the weak part, the weak part is connected around the protruding part, the bearing 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 a side away from the electrode assembly, and the protruding part is provided with a concave part that is concave toward a side close to the electrode assembly; wherein the weak part includes a first surface close to the electrode assembly in the thickness direction of the cover plate, in the thickness direction, there is a minimum dimension C mm between the concave part and the first surface, and there is a maximum dimension D mm between the protruding part and the first surface, satisfying: 0.3≤DC≤0.6. By providing the protrusion and the recess and further limiting the difference range of the protrusion and the recess in the thickness direction, it can be ensured that the explosion-proof valve can absorb and disperse the stress caused to the explosion-proof valve by the pressure difference inside the accommodating cavity and outside the shell during the production of the single cell, thereby avoiding deformation of the explosion-proof valve due to stress concentration, which may lead to cracking of the explosion-proof valve or premature opening of the valve, thereby effectively improving the production yield of the single cell and improving the safety and reliability of the single cell.

[0035] In the present application, a single cell may include a lithium-ion secondary battery, a lithium-ion primary battery, a lithium-sulfur battery, a sodium-lithium-ion battery, a sodium-ion battery or a magnesium-ion battery, etc., and the embodiments of the present application do not limit this. A single cell may be cylindrical, flat, rectangular or other shapes, etc., and the embodiments of the present application do not limit this. Single cells are generally divided into three types according to the packaging method: cylindrical single cells, square single cells and soft-pack single cells, and the embodiments of the present application do not limit this.

[0036] The following is a detailed description of the single cell, battery pack and electrical device of the present application in conjunction with the accompanying drawings. The features of the following embodiments and implementations can be combined with each other if there is no conflict.

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

[0038] refer to Figures 1 to 7The embodiment of the present application provides a single cell, comprising a shell 1, an electrode assembly 2, a cover plate 3 and an explosion-proof valve 4. The shell 1 has a housing chamber 10; the electrode assembly 2 is located in the housing chamber 10; the cover plate 3 is connected to the shell 1 and covers the housing chamber 10, the cover plate 3 is provided with an explosion-proof hole 30, the explosion-proof valve 4 covers the explosion-proof hole 30, the explosion-proof valve 4 includes a bearing portion 40, a weak portion 41 and a protruding portion 42, the bearing portion 40 is connected to the weak portion 41 around, the weak portion 41 is connected to the protruding portion 42 around, the bearing portion 40 is connected to the cover plate 3, and the weak portion 41 is configured to be destroyed when impacted by a preset pressure. When the internal pressure of the single cell is too high (for example, the internal pressure is too high due to overcharging), the weak portion 41 of the explosion-proof valve 4 is destroyed by the preset pressure to release the gas inside the single cell, thereby reducing the internal pressure of the single cell and preventing the single cell from exploding due to excessively rapid pressurization inside the single cell. The protrusion 42 protrudes from the connection with the weak portion 41 toward the side away from the electrode assembly 2, and a recessed portion 420 is provided on the protrusion 42, which is recessed toward the side close to the electrode assembly 2. The arrangement of the protrusion 42 and the recessed portion 420 can avoid stress concentration. Among them, the weak portion 41 includes a first surface 410 close to the electrode assembly 2 in the thickness direction X of the cover plate 3. In the thickness direction X, there is a minimum dimension C mm between the recessed portion 420 and the first surface 410, and there is a maximum dimension D mm between the protrusion 42 and the first surface 410, which satisfies: 0.3≤DC≤0.6. By providing the protrusion 42 and the recess 420 and further limiting the difference range 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 caused to the explosion-proof valve 4 by the pressure difference between the inside of the accommodating chamber 10 and the outside of the shell 1 during the production of the single cell, and avoid deformation of the weak portion 41 due to the pressure difference, which may lead to cracking of the weak portion 41 or premature opening of the explosion-proof valve 4, thereby effectively improving the production yield of the single cell and improving 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 inner concave surface of the recess 420 is too high and the inner concave area is insufficient, so that the explosion-proof valve 4 cannot effectively absorb and disperse the internal pressure during the single cell manufacturing process, which can easily lead to abnormal 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 convex surface of the protrusion 42 is too large. In the single cell manufacturing process, the excessively high convex surface may cause the explosion-proof valve 4 to be easily crushed when it is deformed by abnormal pressure.

[0041] By limiting the difference range of the maximum size between the protrusion 42 and the first surface 410 and the minimum size between the concave portion 420 and the first surface 410, the structural strength, elastic deformation capacity and stress dispersion effect of the explosion-proof valve 4 are balanced to avoid the problem of abnormal concave deformation and cracking of the explosion-proof valve 4 due to unreasonable size, or the problem of abnormal convex deformation of the explosion-proof valve 4 causing crushing, so that the explosion-proof valve 4 can better cope with the change of the internal pressure of the single battery, open the valve in time when it is subjected to the preset pressure, and prevent the internal pressure of the single battery from being too high, resulting in fire, explosion, etc., and ensure the safety and reliability of the single battery.

[0042] In some embodiments, in the thickness direction X, the maximum dimension D between the protrusion 42 and the first surface 410 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 one of 0.7, 0.8, 0.9, 1, 1.1, 1.2 or a range of values ​​between any two of them. When the maximum dimension D between the protrusion 42 and the first surface 410 in the thickness direction X is too small, the curvature of the inner concave surface of the concave portion 420 is too high, and the inner concave area is insufficient, so that the explosion-proof valve 4 cannot effectively absorb and disperse the internal pressure in the single cell process, which easily leads to abnormal 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. In the single cell process, the excessively high outer convex surface may cause the explosion-proof valve 4 to be easily crushed when it is deformed by abnormal pressure. The embodiment of the present application can balance the structural strength, elastic deformation capacity 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 can avoid the problem of abnormal deformation or even cracking of the explosion-proof valve 4 caused by insufficient concave area of ​​the concave portion 420. On the other hand, it can avoid the problem of being crushed when deformed by abnormal pressure due to the excessive convex surface of the protrusion 42, 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 is arranged around the second sub-protrusion 422, and the recess 420 is arranged between the first sub-protrusion 421 and the second sub-protrusion 422 and connected to the first sub-protrusion 421 and the second sub-protrusion 422 respectively. The shape of the explosion-proof valve 4 can be circular or elliptical, and correspondingly, the shapes of the protrusion 42 and the recess 420 can be arranged corresponding to the shape of the explosion-proof valve 4, so as to help the stress on the explosion-proof valve 4 to be more evenly distributed. Figure 7The cross-sectional shapes of the first sub-convex part 421, the second sub-convex part 422 and the concave part 420 can be arc-shaped, circular arc-shaped, etc., and the cross-sectional shapes of the first sub-convex part 421, the concave part 420 and the second sub-convex part 422 arranged in sequence from the outside to the inside can be wavy lines. In this way, on the one hand, stress concentration can be avoided; on the other hand, by setting the first sub-convex part 421, the second sub-convex part 422 and the concave part 420, a large elastic deformation can be performed, so that the stress caused to the explosion-proof valve 4 by the pressure difference between the inside of the accommodating cavity 10 and the outside of the shell 1 during the production of the single battery can be more effectively absorbed and dispersed, and the risk of the weak part 41 cracking due to stress or the explosion-proof valve 4 opening prematurely can be further reduced.

[0044] exist Figure 7 In the illustrated embodiment, in the thickness direction X, there is a minimum dimension B mm between the first sub-convex portion 421 and the first surface 410, and there is a minimum dimension C mm between the concave portion 420 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-convex portion 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-convex portion 421 and the lowest point of the concave portion 420. When the difference between the minimum dimension B between the first sub-convex portion 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-convex portion 421 is too large, and there is a problem of abnormal deformation and cracking of the explosion-proof valve 4 in the single cell manufacturing process. When the difference between the minimum dimension B between the first sub-convex portion 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-convex portion 421 is too small, and there is a problem of abnormal deformation and cracking of the inner concave of the explosion-proof valve 4 during the single cell manufacturing process. The present application can balance the structure of the first sub-convex portion 421 and the concave portion 420 by limiting the difference between the minimum dimension B between the first sub-convex portion 421 and the first surface 410 and the minimum dimension C between the concave portion 420 and the first surface 410, so that it can better cope with internal pressure changes during the manufacturing process of the single cell, avoid deformation and damage of the explosion-proof valve 4 caused by unreasonable structure, and thus ensure the safety and reliability of the single cell.

[0045] exist Figure 7In the illustrated embodiment, the bearing 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 bearing portion 40 may 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 of values ​​between any two of them. Such an arrangement can ensure the connection stability between the bearing portion 40 and the cover plate 3, prevent the explosion-proof valve 4 from loosening or falling off due to unstable connection during the manufacturing process of the single cell or during normal use, and improve the safety and reliability of the single cell.

[0046] exist Figure 7 In the illustrated embodiment, the bearing portion 40 has a maximum dimension A mm in the thickness direction X, and a minimum dimension C mm between the recess 420 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 bearing portion 40 in the thickness direction X, it is possible to ensure that the concave height of the recess 420 is within a reasonable dimension range, thereby avoiding the problem of the explosion-proof valve 4 being concave, and further avoiding the problem of the explosion-proof valve 4 being cracked or opening the valve in advance, thereby effectively improving the production yield of the single cell and improving the safety and reliability of the single cell.

[0047] In the embodiment of the present application, explosion-proof valves 4 of different sizes A, B, C and D are provided and welded to the cover plate 3 for actual measurement and verification, and whether abnormal conditions occur in the explosion-proof valve 4 during the single cell manufacturing process is tracked. The verification results are shown in Table 1.

[0048] Table 1:

[0049]

[0050]

[0051] Referring to Example 1 to Example 9 in Table 1, when the single cell meets 0.3≤DC≤0.6, 0.05≤BC≤0.15, A<C, 0.4≤A≤0.6 and 0.7≤D≤1.2, there is no deformation or abnormal cracking of the explosion-proof valve 4 such as concave or convex in the single cell manufacturing process. It can be understood that by limiting the size 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 inside of the accommodating cavity 10 and the outside of the shell 1 in the production process of the single cell, and avoid the explosion-proof valve 4 from being concave or convex due to stress concentration, which leads to the problem of cracking or premature opening of the explosion-proof valve 4, thereby effectively improving the production yield of the single cell and improving the safety and reliability of the single cell.

[0052] Referring to Table 1, comparative example 1, DC=0.3, 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, but BC is less than 0.04, and does not meet the requirements of 0.05≤BC≤0.15. The verification result is that the height of the first sub-convex portion 421 is too small, and the single cell process has the problem of abnormal deformation and cracking of the inner concave of the explosion-proof valve 4. It can be understood that due to the small difference in BC, the distance between the first sub-convex portion 421 and the concave portion 420 in the thickness direction X is too close, resulting in a small height of the first sub-convex portion 421. This will make the curvature of the inner concave surface of the concave portion 420 too high, and the inner concave area is insufficient. The explosion-proof valve 4 cannot effectively absorb and disperse the internal pressure in the single cell process, resulting in abnormal deformation and even cracking of the inner concave.

[0053] Referring to Table 1, Example 2, 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, but BC is greater than 0.15, and does not meet the requirement of 0.05 ≤ BC ≤ 0.15. The verification result is that the height of the first sub-convex portion 421 is too large, and the single cell process has the problem of abnormal deformation and cracking of the convex outer surface of the explosion-proof valve 4. It can be understood that because the value of BC is large, the distance between the first sub-convex portion 421 and the concave portion 420 in the thickness direction X is too large, so that the height of the first sub-convex portion 421 is too large. In the single cell process, the excessively high convex surface may cause the explosion-proof valve 4 to be easily crushed when it is deformed by abnormal pressure, resulting in abnormal deformation and cracking of the convex outer surface.

[0054] Referring to Table 1, Example 3, 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, but BC is greater than 0.15, and does not meet the requirement of 0.05 ≤ BC ≤ 0.15. The verification result is that the height of the first sub-convex portion 421 is too large, and the single cell process has the problem of abnormal deformation and cracking of the convex outer surface of the explosion-proof valve 4. It can be understood that because the value of BC is large, the distance between the first sub-convex portion 421 and the concave portion 420 in the thickness direction X is too large, so that the height of the first sub-convex portion 421 is too large. In the single cell process, the excessively high convex surface may cause the explosion-proof valve 4 to be easily crushed when it is deformed by abnormal pressure, resulting in abnormal deformation and cracking of the convex outer surface.

[0055] Referring to Table 1, Example 4, DC = 0.29, 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, but DC is less than 0.3, which does not meet the requirement of 0.3 ≤ DC ≤ 0.6. The verification result is that the curvature of the inner concave surface of the concave portion 420 is too high, the inner concave area is insufficient, and the single cell process has the problem of abnormal deformation and cracking of the inner concave of the explosion-proof valve 4. It can be understood that due to the small value of DC, the difference between the protrusion 42 and the concave portion 420 in the thickness direction X is small, resulting in a high curvature of the inner concave surface of the concave portion 420 and insufficient inner concave area. This will make it impossible for the explosion-proof valve 4 to effectively absorb and disperse the internal pressure in the single cell process, resulting in abnormal deformation and even cracking of the inner concave.

[0056] Referring to Table 1, Example 5, DC = 0.61, 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, but DC is greater than 0.6, and does not meet the requirement of 0.3 ≤ DC ≤ 0.6. The verification result is that the height of the second sub-convex portion 422 is too large, and there is a problem of abnormal crushing of the explosion-proof valve 4 in the single cell process. It can be understood that due to the large value of DC, the difference between the protrusion 42 and the concave portion 420 in the thickness direction X is too large, resulting in a large height of the second sub-convex portion 422. In the single cell process, an overly high convex portion may cause the explosion-proof valve 4 to be easily crushed when it is deformed by abnormal pressure.

[0057] Referring to Table 1, Example 6, DC=0.55, BC=0.1, 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 is that the inner concave surface of the concave portion 420 is low, and the explosion-proof valve 4 has many concave problems in the vacuum pumping process in the single cell process. It can be understood that since A≥C does not meet the conditions, the overall structure of the explosion-proof valve 4 is affected, resulting in a low inner concave surface of the concave portion 420. In the vacuum pumping process in the single cell process, the explosion-proof valve 4 cannot effectively cope with the internal pressure changes and is prone to concave problems.

[0058] Referring to Table 1, Example 7, 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 is that the inner concave surface of the concave portion 420 is low, and the explosion-proof valve 4 has many concave problems in the vacuum pumping process in the single cell process. It can be understood that since A ≥ C does not meet the conditions, the overall structure of the explosion-proof valve 4 is affected, resulting in a low inner concave surface of the concave portion 420. In the vacuum pumping process in the single cell process, the explosion-proof valve 4 cannot effectively cope with the internal pressure changes and is prone to concave problems.

[0059] In some embodiments, a notch 411 is provided on the weak portion 41, and the notch 411 is provided around the protrusion 42. By providing the notch 411, the weak portion 41 can be more accurately ruptured at the notch 411 when subjected to a preset pressure, ensuring that the explosion-proof valve 4 releases the internal gas of the single cell in time at an appropriate pressure, thereby effectively reducing the internal pressure and preventing the single cell from being in danger.

[0060] In some embodiments, the notch 411 may be disposed on a side of the weak portion 41 away from the electrode assembly 2 and recessed in a direction toward the electrode assembly 2. In other embodiments, the notch 411 may be disposed on a side of the weak portion 41 close to the electrode assembly 2 and recessed in a direction away from the electrode assembly 2. Figure 3 , Figure 5 and Figure 7 In the illustrated embodiment, the notch 411 is disposed on a side of the weak portion 41 away from the electrode assembly 2 and is recessed toward the electrode assembly 2. The notch 411 may be formed by laser etching or by mechanical processing, and the present application does not limit this.

[0061] exist Figure 2 and Figure 7 In the illustrated embodiment, the bearing portion 40 is connected to the side of the cover plate 3 close to the electrode assembly 2, and the protruding portion 42 protrudes into the explosion-proof hole 30. The explosion-proof valve 4 is arranged on the side of the cover plate 3 close to the electrode assembly 2, which can avoid the problem of the explosion-proof valve 4 being easily damaged by scratches when welding the explosion-proof valve 4 on the outer wall of the cover plate 3, and ensure the connection stability 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 provided on one side of the cover plate 3 close to the electrode assembly 2. The limiting groove 31 is arranged around the explosion-proof hole 30 and is arranged on one side of the cover plate 3 close to the electrode assembly 2. The bearing portion 40 is arranged in the limiting groove 31. The limiting groove 31 can play a role in positioning and fixing the explosion-proof valve 4. By providing the limiting groove 31 on the cover plate 3 and arranging the explosion-proof valve 4 in the limiting groove 31, the explosion-proof valve 4 will not occupy the space of the electrode assembly 2 in the accommodating cavity 10, thereby improving the energy density and performance of the single battery.

[0063] exist Figure 7 In the illustrated embodiment, along the thickness direction X of the cover plate 3, there is a minimum dimension E mm between the bottom wall 310 of the limit groove 31 and the side of the cover plate 3 close to the electrode assembly 2, and the bearing portion 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 limit groove 31 and the side of the cover plate 3 close to the electrode assembly 2 to be greater than or equal to the maximum dimension A of the bearing portion 40, it is possible to prevent the explosion-proof valve 4 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 accommodating cavity 10, thereby improving the energy density and performance of the single cell. Furthermore, it is also possible to prevent the explosion-proof valve 4 from colliding or scratching with other components under vibration conditions, thereby reducing the possibility of danger to the single cell due to damage to the explosion-proof valve 4.

[0064] In some embodiments, there are multiple recesses 420, and the multiple recesses 420 are arranged on the protrusion 42, and one of two adjacent recesses 420 is arranged around the other. In some embodiments, the multiple recesses 420 can be connected to each other. In other embodiments, the multiple recesses 420 can be arranged on the protrusion 42 at intervals.

[0065] In some embodiments, the area of ​​the protrusion 42 is S1 mm 2 , the area of ​​explosion-proof valve 4 is S2 mm 2, satisfying: 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 can be understood that the area occupied by the protrusion 42 in the explosion-proof valve 4 is too large, thereby occupying the space of the weak part 41. This may cause the weak part 41 to fail to be destroyed normally when subjected to a preset pressure, affecting the function of the explosion-proof valve 4 to release the 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 is impossible to fully absorb and disperse the pressure difference stress from the production process of the single battery, which is easy to cause the weak part 41 to crack due to stress concentration or cause the explosion-proof valve 4 to open the valve in advance, reducing the safety and reliability of the single battery. By limiting the ratio range 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 are controlled within a certain ratio range, which can ensure that the protrusion 42 reaches a relatively ideal state when playing the role of absorbing and dispersing stress. The protrusion 42 will not be too small to effectively disperse stress, nor will it be too large to affect the pressure relief function of the explosion-proof valve 4. A reasonable area ratio helps the explosion-proof valve 4 to quickly release internal gas when the internal pressure of the single battery is too high, reduce the internal pressure, and improve the safety and reliability of the single battery.

[0066] The present application embodiment provides a battery pack, including the above-mentioned single battery, so the battery pack can have all the technical features and beneficial effects of the above-mentioned single battery, which will not be repeated here. The battery pack also includes a box body, wherein at least one single battery is accommodated inside the box body.

[0067] Correspondingly, the embodiment of the present application also provides an electrical device, including the above-mentioned single cell, or, including the above-mentioned battery pack, so the electrical device can have all the technical features and beneficial effects of the above-mentioned single cell or battery pack, which will not be repeated here. The electrical device can be a mobile phone, a portable device, a laptop computer, an electric car, an electric car, a ship, a spacecraft, an electric toy, and an electric tool. For example, spacecraft include airplanes, rockets, space shuttles, and spacecrafts; electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys; electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers.

[0068] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0069] The above is a detailed introduction to a single cell battery, a battery pack and an electrical device provided in the embodiments of the present application, and specific examples are used to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the technical solution and its core idea of ​​the present application; ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents; and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the present application.

Claims

1. A single cell battery, characterized in that: include: A housing having a receiving cavity; an electrode assembly, wherein the electrode assembly is located in the accommodating cavity; A cover plate, the cover plate is connected to the shell and covers the accommodating cavity, and the cover plate is provided with an explosion-proof hole; An explosion-proof valve, the explosion-proof valve covers the explosion-proof hole, the explosion-proof valve comprises a bearing portion, a weak portion and a protruding portion, the bearing portion is connected to the weak portion in a surrounding manner, the weak portion is connected to the protruding portion in a surrounding manner, the bearing 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 a connection with the weak portion toward a side away from the electrode assembly, and the protruding portion is provided with a concave portion that is concave toward a side close to the electrode assembly; The weak portion includes a first surface close to the electrode assembly in the thickness direction of the cover plate, and in the thickness direction, the concave portion and the first surface have a minimum dimension C mm, and the protruding portion and the first surface have a maximum dimension D mm, satisfying: 0.3≤DC≤0.

6.

2. The single cell according to claim 1, characterized in that: The protrusion includes a first sub-protrusion and a second sub-protrusion, the first sub-protrusion is arranged around the second sub-protrusion, and the recess is arranged between the first sub-protrusion and the second sub-protrusion and is connected to the first sub-protrusion and the second sub-protrusion respectively.

3. The single cell according to claim 2, characterized in that: In the thickness direction, a minimum dimension B mm exists between the first sub-convex portion and the first surface, satisfying: 0.05≤BC≤0.

15.

4. The single cell according to claim 1, characterized in that: The bearing portion has a maximum dimension A mm in the thickness direction, and the single battery satisfies: A<C, 0.4≤A≤0.

6.

5. The single cell according to claim 1, characterized in that: The single cell satisfies: 0.7≤D≤1.

2.

6. The single cell according to claim 1, characterized in that: The bearing portion is connected to a side of the cover plate close to the electrode assembly, and the protruding portion protrudes into the explosion-proof hole.

7. The single cell according to claim 1 or 6, characterized in that: A limiting groove is provided on one side of the cover plate close to the electrode assembly, the limiting groove is arranged around the explosion-proof hole, the limiting groove is provided on one side of the cover plate close to the electrode assembly, and the bearing part is arranged in the limiting groove.

8. The single cell according to claim 7, characterized in that: Along the thickness direction, there is a minimum dimension E mm between the bottom wall of the limiting groove and the side of the cover plate close to the electrode assembly, and the bearing portion has a maximum dimension A mm, satisfying: E≥A.

9. A battery pack, characterized in that: The invention comprises the single cell according to any one of claims 1 to 8.

10. An electrical device, characterized in that: The method comprises the single cell according to any one of claims 1 to 8, or comprises the battery pack according to claim 9.

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