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 cover plate which is connected with a shell and covers a containing cavity, the cover plate is provided with an anti-explosion hole, an anti-explosion valve covers the anti-explosion hole, the anti-explosion valve comprises a bearing part, a weak part, a protruding part and a concave part which are sequentially connected in a surrounding mode from outside to inside, and the bearing part is connected with the cover plate; the protruding part protrudes towards one side far away from the electrode assembly from the joint with the weak part, and the concave part sinks towards one side close to the electrode assembly; 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 maximum size between the protruding part and the first surface is B mm, the minimum size between the concave part and the first surface is C mm, and 0.15 < = B-C < = 0.5 is satisfied. By limiting the difference value range between the protruding part and the concave part in the thickness direction, the protruding part and the concave part can fully 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 liquid injection, pre-charging formation, and capacity division in the single cell process, 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, a protruding portion and a concave portion which are connected in sequence from the outside to the inside, 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 the concave portion is concave toward a side close to the electrode assembly;

[0009] Among them, the weak part includes the first surface close to the electrode assembly in the thickness direction of the cover plate. In the thickness direction, the maximum dimension between the protrusion and the first surface is B mm, and the minimum dimension between the recess and the first surface is C mm, satisfying: 0.15≤BC≤0.5.

[0010] In some embodiments, in the thickness direction, the bearing portion has a maximum dimension of A mm, satisfying: C>A, 0.4≤A≤0.6.

[0011] In some embodiments, the recess has a first size W in the width direction of the cover plate. 1 mm, satisfying: 10≤W 1 / (BC)≤15, the width direction intersects with the thickness direction.

[0012] In some embodiments, in the thickness direction, the maximum dimension A of the bearing portion satisfies: 0.25≤BA≤1.1.

[0013] In some embodiments, in the width direction of the cover plate, the bearing portion has a maximum dimension W mm, satisfying: 15≤W / A≤70.

[0014] In some embodiments, the protrusion has a second size W in the width direction of the cover plate. 2 mm, satisfying: 4≤W 2 / B≤7.

[0015] 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.

[0016] In some embodiments, 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 and is provided on one side of the cover plate close to the electrode assembly. The bearing portion is arranged in the limiting groove.

[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, the explosion-proof valve covers the explosion-proof hole, and the explosion-proof valve includes a bearing portion, a weak portion, a protruding portion and a recessed portion that are sequentially connected from the outside to the inside, the bearing portion is connected to the cover plate, the weak portion is configured to be destroyed when subjected to a preset pressure shock, the protruding portion protrudes from the connection with the weak portion toward the side away from the electrode assembly, and the recessed portion is recessed toward the side close to the electrode assembly; wherein the weak portion includes a first surface close to the electrode assembly in the thickness direction of the cover plate, in the thickness direction, the maximum dimension between the protruding portion and the first surface is B mm, and the minimum dimension between the recessed portion and the first surface is C mm, satisfying: 0.15≤BC≤0.5. By limiting the difference range between the protrusion and the recess in the thickness direction, it is ensured that the setting of the protrusion and the recess can fully absorb and disperse the stress brought to the explosion-proof valve by the pressure difference inside the accommodating cavity and outside the shell during the production of the single cell, avoiding local stress concentration causing deformation of the explosion-proof valve, and further causing the explosion-proof valve to crack or open prematurely, 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 4 is a bottom view of an explosion-proof valve according to an embodiment of the present application;

[0027] Figure 5 is a cross-sectional view of a cover plate according to an embodiment of the present application;

[0028] Figure 6 It is a cross-sectional view of a cover plate according to yet another embodiment of the present application.

[0029] 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, protruding part; 43, recessed part; 310, bottom wall; 410, first surface; 411, notch; X, thickness direction. DETAILED DESCRIPTION

[0030] 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.

[0031] 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.

[0032] 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 liquid injection, pre-charging formation, and capacity division in the single cell process, 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.

[0033] In view of this, 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, a protruding part and a recessed part that are sequentially connected from the outside to the inside, 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 the side away from the electrode assembly, and the recessed part is recessed toward the 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, and in the thickness direction, the maximum dimension between the protruding part and the first surface is B mm, and the minimum dimension between the recessed part and the first surface is C mm, satisfying: 0.15≤BC≤0.5. By limiting the difference range between the protrusion and the recess in the thickness direction, it is ensured that the setting of the protrusion and the recess can fully absorb and disperse the stress brought to the explosion-proof valve by the pressure difference inside the accommodating cavity and outside the shell during the production of the single cell, avoiding local stress concentration causing deformation of the explosion-proof valve, and further causing the explosion-proof valve to crack or open prematurely, thereby effectively improving the production yield of the single cell and improving the safety and reliability of the single cell.

[0034] 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.

[0035] 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.

[0036] 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 cross-sectional view of a cover plate according to an embodiment of the present application; Figure 6 It is a cross-sectional view of a cover plate according to yet another embodiment of the present application.

[0037] refer to Figures 1 to 6 The embodiment of the present application provides a single cell, a battery pack and an electric device, including 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, and the explosion-proof valve 4 includes a bearing portion 40, a weak portion 41, a protruding portion 42 and a recessed portion 43 which are connected in sequence from the outside to the inside. Specifically, the bearing portion 40 is connected to the weak portion 41, the weak portion 41 is connected to the protruding portion 42, and the protruding portion 42 is connected to the recessed portion 43. 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 large (for example, the internal pressure is too large 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 the recess 43 is recessed toward the side close to the electrode assembly 2. The arrangement of the protrusion 42 and the recess 43 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, the maximum dimension between the protrusion 42 and the first surface 410 is B mm, and the minimum dimension between the recess 43 and the first surface 410 is C mm, which satisfies: 0.15≤BC≤0.5. By limiting the difference range between the protrusion 42 and the recess 43 in the thickness direction X, it is ensured that the arrangement of the protrusion 42 and the recess 43 can fully absorb and disperse the stress brought to the explosion-proof valve 4 by the pressure difference between the accommodating cavity 10 and the outside of the shell 1 during the production of the single cell, avoid the deformation of the explosion-proof valve 4 caused by the local stress concentration, and then cause the explosion-proof valve 4 to crack or open the valve in advance, thereby effectively improving the production yield of the single cell and improving the safety and reliability of the single cell.

[0038] exist Figure 6In the illustrated embodiment, in the thickness direction X, the maximum dimension between the protrusion 42 and the first surface 410 is B mm, and the minimum dimension between the recess 43 and the first surface 410 is C mm, satisfying: 0.15≤BC≤0.5. It can be understood that when the difference between the maximum dimension B between the protrusion 42 and the first surface 410 and the minimum dimension C between the recess 43 and the first surface 410 is too large, the height of the protrusion 42 is relatively high, resulting in a small distance between the protrusion 42 and the side of the cover plate 3 away from the electrode assembly 2, and there is a risk of the explosion-proof valve 4 being crushed in the single cell process. On the other hand, the concave part of the recess 43 is relatively high, and may be deformed due to local stress concentration during the production process, increasing the risk of abnormal concave deformation or even cracking of the explosion-proof valve 4. When the difference between the maximum dimension B between the protrusion 42 and the first surface 410 and the minimum dimension C between the recess 43 and the first surface 410 is too small, the protrusion 42 and the recess 43 may not be able to absorb and disperse the pressure in a timely and effective manner, thereby increasing the risk of the explosion-proof valve 4 becoming concave and convex, thereby causing cracking or premature valve opening. The present application reasonably controls the difference range between the maximum dimension B between the protrusion 42 and the first surface 410 and the minimum dimension C between the recess 43 and the first surface 410, fully absorbs and disperses the stress caused by the pressure difference inside the accommodating cavity 10 and outside the shell 1 to the explosion-proof valve 4 during the production of the single cell, avoids the problem of local stress concentration causing the explosion-proof valve 4 to become concave and convex, thereby causing the explosion-proof valve 4 to crack or premature valve opening, thereby effectively improving the production yield of the single cell and improving the safety and reliability of the single cell.

[0039] exist Figure 6 In the illustrated embodiment, in the thickness direction X, the maximum dimension A of the bearing portion 40 satisfies: 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. This arrangement ensures the connection stability between the bearing portion 40 and the cover plate 3, prevents 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 improves the safety and reliability of the single cell.

[0040] exist Figure 6In the illustrated embodiment, in the thickness direction X, the maximum dimension A of the bearing portion 40 and the minimum dimension C between the recess 43 and the first surface 410 satisfy: C>A. By limiting the minimum dimension C between the recess 43 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 indentation height of the recess 43 is within a reasonable size range, thereby avoiding the indentation problem of the explosion-proof valve 4, and further avoiding the problem of the explosion-proof valve 4 cracking or premature opening, thereby effectively improving the production yield of the single cell and improving the safety and reliability of the single cell.

[0041] exist Figure 6 In the illustrated embodiment, in the thickness direction X, the maximum dimension A of the bearing portion 40 and the maximum dimension B between the protrusion 42 and the first surface 410 satisfy: 0.25≤BA≤1.1. If the difference in BA is too large, the protrusion height of the protrusion 42 relative to the bearing portion 40 is large, and the overall convex height of the protrusion 42 is high, and there is a risk of the explosion-proof valve 4 being crushed. If the difference in BA is too small, the protrusion height of the protrusion 42 relative to the bearing portion 40 is small, and the overall convex height of the protrusion 42 is low. In the negative pressure extraction processes such as liquid injection and sealing nailing in the single cell manufacturing process, due to the effect of external pressure, the explosion-proof valve 4 may be subjected to inward pressure, and then the problem of concave deformation occurs.

[0042] In the embodiment of the present application, explosion-proof valves 4 of different sizes A, B and C 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.

[0043] Table 1:

[0044]

[0045]

[0046] With reference to Examples 1 to 9, the single cells all satisfy 0.15≤BC≤0.5, C>A, 0.4≤A≤0.6 and 0.25≤BA≤1.1, and the verification results are that the explosion-proof valve 4 in the single cell manufacturing process does not have abnormal problems such as concave and convex deformation, crushing, premature opening, etc.

[0047] Referring to comparative example 1, BC=0.45, BA=0.4, the single cell satisfies: 0.15≤BC≤0.5, 0.25≤BA≤1.1 and 0.4≤A≤0.6, but does not satisfy C>A, and the verification result is that the height of the concave part of the concave portion 43 is insufficient, and the explosion-proof valve 4 has a concave deformation problem. It can be understood that when the minimum dimension C between the concave portion 43 and the first surface 410 is relatively small, due to the insufficient height of the concave part of the concave portion 43, when subjected to stress, the concave portion 43 may not be able to effectively deform to disperse the stress, resulting in stress concentration in the concave portion 43, thereby causing the explosion-proof valve 4 to have a concave deformation problem.

[0048] Referring to comparative example 2, BC=0.1, BA=0.2, the single cell satisfies: C>A, 0.4≤A≤0.6, but does not satisfy 0.15≤BC≤0.5, 0.25≤BA≤1.1, and the verification result is that the overall convex height of the protrusion 42 is low, and the explosion-proof valve 4 has a concave deformation problem in the negative pressure extraction process such as liquid injection and sealing nailing in the single cell process. It can be understood that the protrusion 42 has a small protrusion height relative to the bearing part 40 and the concave part 43. In the negative pressure extraction process such as liquid injection and sealing nailing in the single cell process, the external pressure will act on the explosion-proof valve 4, making the explosion-proof valve 4 easily deformed inward.

[0049] Referring to Comparative Example 3, BC=0.55, BA=0.65, the single battery satisfies: C>A, 0.4≤A≤0.6 and 0.25≤BA≤1.1, but does not satisfy 0.15≤BC≤0.5, and the verification result is that the height of the inner concave part of the concave part 43 is not enough, and the explosion-proof valve 4 has the problem of inner concave deformation. It can be understood that the distance between the highest point of the protrusion 42 and the lowest point of the concave part 43 is relatively large, the height of the inner concave part of the concave part 43 is not enough, and the external pressure will act on the explosion-proof valve 4, making the explosion-proof valve 4 easily deformed inward.

[0050] Referring to comparative example 4, BC=1.06, BA=1.11, the single cell satisfies: C>A, 0.4≤A≤0.6 and 0.25≤BA≤1.1, but does not satisfy 0.15≤BC≤0.5. The verification result is that the overall convex height of the protrusion 42 is too high, the distance between the explosion-proof valve 4 and the upper surface of the cover plate 3 is small, and there is a problem of the explosion-proof valve 4 being crushed in the single cell process. It can be understood that the distance between the highest point of the protrusion 42 and the lowest point of the recess 43 is too large, and the height of the convexity of the protrusion 42 is too high, resulting in a small distance between the protrusion 42 and the side of the cover plate 3 away from the electrode assembly 2, and there is a risk of the explosion-proof valve 4 being crushed in the single cell process.

[0051] exist Figure 6In the illustrated embodiment, in the thickness direction X, the maximum dimension between the protrusion 42 and the first surface 410 is B mm, the minimum dimension between the recess 43 and the first surface 410 is C mm, and in the width direction Y of the cover plate 3, the recess 43 has a first dimension W 1 mm, satisfying: 10≤W 1 / (BC)≤15, the width direction Y intersects the thickness direction X. By limiting the ratio range of the first dimension of the concave portion 43 in the width direction Y and the height difference between the protrusion 42 and the concave portion 43 in the thickness direction X, it is ensured that the protrusion 42 and the concave portion 43 can fully absorb and disperse the stress caused by the pressure difference inside the accommodating cavity 10 and outside the shell 1 to the explosion-proof valve 4 during the production of the single battery, avoiding the problem of the explosion-proof valve 4 being concave inside and convex outside due to local stress concentration, and then causing the explosion-proof valve 4 to crack or open prematurely, thereby effectively improving the production yield of the single battery and improving the safety and reliability of the single battery.

[0052] exist Figure 6 In the embodiment shown, in the width direction Y, the protrusion 42 has a second dimension W 2 mm, the maximum dimension B between the protrusion 42 and the first surface 410 in the thickness direction X satisfies: 4≤W 2 / B≤7. It is understandable that if W 2 / B ratio is too large, the overall convex height of the protrusion 42 is too low, and in the negative pressure extraction process such as liquid injection and sealing nailing in the single cell manufacturing process, the explosion-proof valve 4 may be subjected to inward pressure due to the effect of external pressure, and then the problem of concave deformation occurs. 2 The ratio of / B is too small, the overall convex height of the protrusion 42 is too high, the explosion-proof valve 4 is close to the upper surface of the cover plate 3, and the explosion-proof valve 4 may be crushed. 2 The ratio range of the maximum dimension B between the protrusion 42 and the first surface 410 in the thickness direction X can avoid the explosion-proof valve 4 from being deformed inward and crushed, thereby ensuring the safety and reliability of the single cell manufacturing process.

[0053] exist Figure 6In the embodiment shown, in the thickness direction X, the bearing part 40 has a maximum dimension A mm, and in the width direction Y, the bearing part 40 has a maximum dimension W mm, satisfying: 15≤W / A≤70. If the ratio of W / A is too small, the maximum dimension A of the bearing part 40 in the thickness direction X is too large, so that the overall convex height of the protrusion 42 is too high, the distance between the explosion-proof valve 4 and the upper surface of the cover plate 3 is small, and there is a problem of the explosion-proof valve 4 being crushed. If the ratio of W / A is too large, the maximum dimension A of the bearing part 40 in the thickness direction X is too small, and the size design of the explosion-proof valve 4 is unreasonable, resulting in insufficient overall strength of the explosion-proof valve 4, and the problem of abnormal convex and concave deformation in the single cell process. The embodiment of the present application can ensure the structural stability of the explosion-proof valve 4 by limiting the ratio range of the maximum dimension W of the bearing part 40 in the width direction Y relative to the maximum dimension A of the bearing part 40 in the thickness direction X, avoid the problem of the explosion-proof valve 4 being crushed and abnormal convex and concave deformation, ensure the safety and reliability in the single cell process, and improve the production yield of the single cell.

[0054] 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.

[0055] 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 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.

[0056] exist Figure 2 and Figure 5 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.

[0057] exist Figure 2 and Figure 5In 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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, a protruding portion and a concave portion which are connected in sequence from the outside to the inside, the bearing portion is connected to the cover plate, the weak portion is configured to be destroyed when impacted by a preset pressure, the protruding portion protrudes from the connection with the weak portion toward a side away from the electrode assembly, and the concave portion is recessed toward a side close to the electrode assembly; Wherein, 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 maximum dimension between the protrusion and the first surface is B mm, and the minimum dimension between the recess and the first surface is C mm, satisfying: 0.15≤BC≤0.

5.

2. The single cell according to claim 1, characterized in that: In the thickness direction, the bearing portion has a maximum dimension of A mm, satisfying: C>A, 0.4≤A≤0.

6.

3. The single cell according to claim 2, characterized in that: In the width direction of the cover plate, the recess has a first size W1 mm, satisfying: 10≤W1 / (BC)≤15, and the width direction intersects the thickness direction.

4. The single cell according to claim 1, characterized in that: In the thickness direction, the maximum dimension A of the bearing portion satisfies: 0.25≤BA≤1.

1.

5. The single cell according to claim 1, characterized in that: In the width direction of the cover plate, the bearing portion has a maximum dimension W mm, satisfying: 15≤W / A≤70.

6. The single cell according to claim 1, characterized in that: In the width direction of the cover plate, the protrusion has a second size W2 mm, satisfying: 4≤W2 / B≤7.

7. 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.

8. The single cell according to claim 1 or 7, 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 and is provided on one side of the cover plate close to the electrode assembly. The bearing portion is arranged in the limiting groove.

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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