Cover plate assembly, single battery and battery pack

Abstract

The invention discloses a cover plate assembly, a single battery and a battery pack, and belongs to the technical field of batteries, the cover plate assembly comprises: a cover plate body having a through hole; the explosion-proof valve is connected to the cover plate body and covers and seals the through hole, the explosion-proof valve comprises a main body part, a connecting part and a welding part, the main body part protrudes in the thickness direction of the cover plate body, the surface of one side in the thickness direction is an arc-shaped surface, and the connecting part is arranged around the periphery of the main body part and is connected with the main body part. By arranging the main body part of the explosion-proof valve into the arc-shaped structure, the rigidity of the main body part can be enhanced, the non-deformability of the main body part can be improved, and meanwhile, the connecting part and the welding part of the explosion-proof valve meet the requirement of a certain angle, so that the rigidity of the main body part can be further improved, and the non-deformability of the main body part can be improved in the use process of the battery. Even if the anti-explosion valve is affected by external force, the anti-explosion valve is not prone to deformation, so that it is guaranteed that the opening pressure of the anti-explosion valve does not change, and the anti-explosion valve can work normally.

Description

Technical Field

[0001] The present application belongs to the field of battery technology, and in particular relates to a cover plate assembly, a single cell and a battery pack. Background Art

[0002] The battery explosion-proof valve is a safety device used in battery systems to prevent the battery from exploding or catching fire under abnormal circumstances and to improve the safety of the battery during use. However, when the battery is in use, it may be affected by external forces, causing the explosion-proof valve to deform, thereby affecting the opening pressure of the explosion-proof valve. Summary of the invention

[0003] Purpose of the invention: The embodiment of the present application provides a cover plate assembly, which aims to overcome the technical problem that the explosion-proof valve may be deformed due to the influence of external forces when the battery is in use.

[0004] Technical solution: A cover plate assembly described in an embodiment of the present application includes:

[0005] The cover plate body has a through hole;

[0006] an explosion-proof valve connected to the cover body and sealing the through hole, the explosion-proof valve comprising a main body, a connecting part and a welding part, the main body protruding along the thickness direction of the cover body, and a surface on one side of the thickness direction is an arc surface, the connecting part is arranged around the periphery of the main body and connected to the main body, the welding part is arranged around the periphery of the connecting part and is respectively connected to the connecting part and the cover body;

[0007] The angle between the connecting portion and the welding portion is a, which satisfies: 90°≤a≤175°.

[0008] In some embodiments, the thickness of the welding portion is L, satisfying 0.3 mm ≤ L ≤ 1 mm.

[0009] In some embodiments, the thickness of the welding portion is L, and the thickness of the connecting portion is L1, satisfying: 0.15 mm ≤ L1 ≤ L.

[0010] In some embodiments, the maximum dimension of the explosion-proof valve in the thickness direction of the cover plate body is H, and the thickness of the welding portion is L, satisfying: 0mm≤H-1.1L≤5mm.

[0011] In some embodiments, the main body includes a bursting surface, a scoring segment and an adhesion segment, the scoring segment is connected to the periphery of the bursting surface, the adhesion segment is connected to the periphery of the bursting surface, and two ends of the adhesion segment are respectively connected to two ends of the scoring segment;

[0012] The thickness of the blasting surface is T, the thickness of the notched section is T1, and the thickness of the adhesion section is T2, satisfying: T2 / T1≥1.1, and T2≤T.

[0013] In some embodiments, the main body further comprises:

[0014] The outer ring is arranged around the blasting surface and connected to the connecting portion. The notched segment and the adhesion segment are located between the outer ring and the blasting surface. The outer ring is connected to the blasting surface through the notched segment and the adhesion segment. The thickness of the outer ring is B, satisfying: T≤B≤1.5mm.

[0015] In some embodiments, the orthographic projection area of ​​the main body on the plane perpendicular to the thickness direction is S, and the orthographic projection area of ​​the blasting surface on the plane perpendicular to the thickness direction is S1, satisfying: 50%≤S1 / S≤95%.

[0016] In some embodiments, the thickness of the welding portion is L, and the thickness of the bursting surface is T, satisfying: 15%≤T / L≤70%.

[0017] A single battery, comprising:

[0018] A housing having a receiving cavity;

[0019] As described in any one of the above-mentioned cover plate assemblies, the cover plate assembly is connected to the shell and covers the accommodating cavity.

[0020] A battery pack comprises the single cell described above, or the cover plate assembly described in any one of the above.

[0021] Beneficial effect: The cover assembly of the embodiment of the present application includes: a cover body with a through hole; an explosion-proof valve connected to the cover body and sealing the through hole, the explosion-proof valve includes a main body, a connecting part and a welding part, the main body is convex along the thickness direction of the cover body, and the surface on one side of the thickness direction is an arc surface, the connecting part is arranged around the periphery of the main body, and is connected to the main body, the welding part is arranged around the periphery of the connecting part, and is respectively connected to the connecting part and the cover body; the angle between the connecting part and the welding part is a, which satisfies: 90°≤a≤175°. By setting the main body of the explosion-proof valve into an arc structure, the rigidity of the main body can be enhanced and its anti-deformation ability can be improved. At the same time, the connection part and the welding part of the explosion-proof valve meet the requirements of a certain angle, which can further improve the rigidity of the main body and improve its anti-deformation ability. During the use of the battery, even if the explosion-proof valve is affected by external force, it will not be easily deformed, thereby ensuring that the opening pressure of the explosion-proof valve will not change, so that it can work normally. 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 It is a partial cross-sectional view of the explosion-proof valve and the cover plate body in the embodiment of the present application;

[0024] Figure 2 A three-dimensional diagram of an explosion-proof valve in an embodiment of the present application;

[0025] Figure 3 A top view of the explosion-proof valve in the embodiment of the present application;

[0026] Figure 4 For the embodiment of this application Figure 3 Cross-sectional view of the middle MM;

[0027] Figure 5 For the embodiment of this application Figure 4 Enlarged view of area A in the middle;

[0028] Figure 6 For the embodiment of this application Figure 3 Sectional view of NN;

[0029] Figure 7 For the embodiment of this application Figure 6 Enlarged view of area B in the middle;

[0030] Figure 8 For the embodiment of this application Figure 6 Enlarged view of area C in the middle;

[0031] Figure numerals: 10 - cover plate body; 11 - through hole; 20 - explosion-proof valve; 21 - main body; 211 - explosion surface; 212 - notched section; 213 - adhesion section; 214 - outer ring; 22 - connecting part; 23 - welding part; X - thickness direction. DETAILED DESCRIPTION

[0032] 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.

[0033] In the description of the present application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not 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, "plurality" means two or more, and at least one means one, two or more, unless otherwise clearly and specifically defined.

[0034] A battery explosion-proof valve is a safety device used in battery systems to prevent the battery from exploding or catching fire under abnormal circumstances. It is commonly used in high-energy-density batteries such as lithium-ion batteries, because these batteries may experience dangerous conditions such as overheating, overvoltage, or overcharging when they are charged, discharged, or damaged externally. The main function of a battery explosion-proof valve is to monitor the pressure and temperature inside the battery and take measures to prevent the battery from exploding when the preset safety threshold is reached. When the internal pressure or temperature of the battery exceeds the safe range, the explosion-proof valve will automatically open to release the pressure inside the battery to prevent the battery from overheating or exploding. In addition, the battery explosion-proof valve can also prevent external flames from entering the battery, preventing flames from entering the battery, thereby reducing the risk of fire. However, the battery will inevitably be affected by external forces during use. External forces may cause the explosion-proof valve on the battery to deform, which will affect the residual thickness of the explosion-proof valve notch, resulting in a decrease in the opening pressure of the explosion-proof valve or even air leakage, which may make the explosion-proof valve easy to open or increase the difficulty of opening the explosion-proof valve. Both of these situations will affect the opening pressure of the explosion-proof valve, causing the explosion-proof valve to be opened before the pressure inside the battery reaches the preset pressure value, or the explosion-proof valve to be not opened before the pressure inside the battery reaches the preset pressure value, thereby affecting the safety of the battery during use.

[0035] In view of this, an embodiment of the present application provides a cover assembly to overcome at least one of the above-mentioned technical problems.

[0036] See also Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 In the embodiment of the present application, the cover assembly includes a cover body 10 and an explosion-proof valve 20. After the bare cell is installed in the battery shell, the shell can be sealed by the cover body 10 to isolate the inside of the battery from the external environment, play a certain protective role on the structure inside the battery shell, and provide a good working environment for these structures.

[0037] The cover body 10 has a through hole 11. The explosion-proof valve 20 is connected to the cover body 10 and seals the through hole 11. The through hole 11 is used to connect the inside of the shell with the external environment in some specific cases (such as when the battery needs to release pressure or dissipate heat), and the explosion-proof valve 20 is used to seal the through hole 11. Under normal circumstances, the explosion-proof valve 20 is closed to prevent the inside of the battery shell from being connected to the external environment through the through hole 11. The explosion-proof valve 20 includes a main body 21, a connecting part 22 and a welding part 23. The main body 21 is raised along the thickness direction X of the cover body 10, and the surface on one side of the thickness direction X is an arc-shaped surface. The connecting part 22 is arranged around the periphery of the main body 21 and is connected to the main body 21. The welding part 23 is arranged around the periphery of the connecting part 22 and is respectively connected to the connecting part 22 and the cover body 10. It can be understood that the explosion-proof valve 20 is welded to the cover body 10 through the welding part 23, so that the explosion-proof valve 20 is fixed as a whole at the position of the through hole 11 on the cover body 10, and the welding part 23 is connected to the main body 21 through the connecting part 22. The explosion-proof valve 20 mainly seals the through hole 11 through the main body 21. The main body 21 has a large force-bearing area, so that the main body 21 is convexly arranged upward (convexly arranged to the side away from the bare battery cell), or convexly arranged downward (convexly arranged to the side facing the bare battery cell). Preferably, the convex direction of the main body 21 is the same as the opening direction of the notch groove (the opening of the notch groove is the groove formed when processing the notch section 212), and one side of the main body 21 along the thickness direction X is an arc surface. By setting the main body 21 into an arc structure, when the main body 21 is subjected to an external force, the arc structure can better transmit the force to the cover body 10 through the connecting part 22 and the welding part 23 to reduce the influence of the force on the main body 21. The arc-shaped structure improves the rigidity of the main body 21 and its ability to resist deformation, thereby preventing the main body 21 from being deformed due to external forces and affecting the opening pressure of the explosion-proof valve.

[0038] The angle between the connection part 22 and the welding part 23 is a, which satisfies: 90°≤a≤175°. It can be understood that the connection part 22 and the welding part 23 of the explosion-proof valve 20 meet the requirements of a certain angle, which can further improve the rigidity of the main body 21 and improve its anti-deformation ability. During the use of the battery, even if the explosion-proof valve 20 is affected by external forces, it will not be easily deformed, thereby ensuring that the opening pressure of the explosion-proof valve 20 will not change, so that it can work normally. Among them, a is generally in the range of 90° to 175°, and a can be any value among 90°, 100°, 110°, 120°, 130°, 140°, 150°, 160°, 170°, and 175°, or a range value between any two values. The value of a can be measured by tools such as a protractor, an electronic angle meter, and a laser rangefinder. The explosion-proof valve 20 can be tested when a has different values, and a force F is applied to the explosion-proof valve 20 to test whether the main body 21 of the explosion-proof valve 20 is deformed. The test results of the embodiment and the comparative example are shown in the following table:

[0039]

[0040] It can be seen from the above table that when the angle a between the connection portion 22 and the welding portion 23 is within the range of 90° to 175°, the main body 21 of the explosion-proof valve 20 can withstand a certain degree of external force without significant deformation, which can avoid changes in the opening pressure of the explosion-proof valve 20 and ensure the normal opening of the explosion-proof valve 20. In the case where a is less than 90°, the opening of the connection portion 22 will be smaller than the bottom space thereof, so that the explosion-proof valve 20 cannot be separated from the mold during processing, which is not conducive to the processing and forming of the explosion-proof valve 20. In the case where a is greater than 175°, when a certain degree of force is applied to the main body 21 of the explosion-proof valve 20, the main body 21 will be significantly deformed, and the deformation will affect the residual thickness of the notched section 212 of the explosion-proof valve 20, thereby reducing the opening pressure of the explosion-proof valve 20 or even causing air leakage.

[0041] See also Figure 4 and Figure 5, combined with the above embodiments, in some embodiments, the thickness of the welding part 23 is L, which satisfies 0.3mm≤L≤1mm. It can be understood that when the thickness of the welding part 23 is in the range of 0.3mm to 1mm, the welding part 23 has good rigidity, which facilitates the welding between the welding part 23 and the cover body 10, and ensures the stability of the welding between the two. When the thickness of the welding part 23 is less than 0.3mm, the thickness of the welding part 23 is thinner. When the welding part 23 is welded to the cover body 10, the welding part 23 may be deformed due to excessive temperature, and it cannot be welded to the cover body 10, or a large weld will appear at the welding point, and the welding quality is poor. Therefore, the thickness of the welding part 23 needs to be kept above 0.3mm. At the same time, within this range, while the welding part 23 meets the welding rigidity requirements, the materials used in production will not be too much, and the cost of the welding part 23 during production will not increase too much. When the thickness of the welding part 23 exceeds 1mm, its cost will increase significantly.

[0042] See also Figure 4 and Figure 5 In combination with the above embodiments, in some embodiments, the thickness of the welding portion 23 is L, and the thickness of the connecting portion 22 is L1, which satisfies: 0.15mm≤L1≤L. It can be understood that in the process of setting the welding portion 23 and the connecting portion 22, the thickness of the connecting portion 22 needs to be greater than or equal to 0.15mm to ensure that the connecting portion 22 has a certain rigidity, so as to prevent the explosion-proof valve 20 from deforming during normal use. When the thickness of the connecting portion 22 is less than 0.15mm, the rigidity is weak and it is easy to deform, which may cause the main body 21 to deform. At the same time, the thickness of the connecting portion 22 needs to be less than or equal to the thickness of the welding portion 23, so that the connecting portion 22 meets certain rigidity requirements while not increasing the difficulty of processing and forming the explosion-proof valve 20, reducing the material used in the connecting portion 22 and reducing costs.

[0043] See also Figure 4 and Figure 5In combination with the above embodiments, in some embodiments, the maximum dimension H of the explosion-proof valve 20 in the thickness direction X of the cover body 10 is H, and the thickness of the welding part 23 is L, which satisfies: 0mm≤H-1.1L≤5mm. It can be understood that when the maximum dimension H of the explosion-proof valve 20 in the thickness direction X of the cover body 10 and the thickness L of the welding part 23 satisfy 0mm≤H-1.1L≤5mm, the explosion-proof valve 20 has relatively good rigidity and anti-deformation ability, which can prevent it from being deformed by a certain external force. At the same time, the explosion-proof valve 20 will not occupy the internal space of the battery shell, avoid occupying the space inside the shell, and affect the volume energy density of the battery. The maximum dimension H of the explosion-proof valve 20 in the thickness direction X of the cover body 10 and the thickness L of the welding part 23 can be measured by measuring tools such as a vernier caliper and a digital caliper. H-1.1L is in the range of 0 mm to 5 mm, and can be any value among 0 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, and 5 mm, or a range value between any two values. The explosion-proof valve 20 is tested within this range, and a force G is applied to the explosion-proof valve 20 to test whether the explosion-proof valve 20 is deformed and whether the explosion-proof valve 20 occupies the internal space of the battery housing. The test results of the embodiments and comparative examples are shown in the following table:

[0044]

[0045] From the above table, it can be seen that when the maximum dimension H of the explosion-proof valve 20 in the thickness direction X of the cover body 10 and the thickness L of the welding portion 23 satisfy 0mm≤H-1.1L≤5mm, the explosion-proof valve 20 does not deform, the normal opening of the explosion-proof valve 20 can be guaranteed, and the explosion-proof valve 20 does not occupy the internal space of the battery shell, and will not affect the normal setting of other structures inside the battery shell.

[0046] See also Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 and Figure 8In combination with the above embodiments, in some embodiments, the main body 21 includes a blasting surface 211, a notched section 212 and an adhesion section 213, the notched section 212 is connected to the periphery of the blasting surface 211, the adhesion section 213 is connected to the periphery of the blasting surface 211, and the two ends of the adhesion section 213 are respectively connected to the two ends of the notched section 212, and the two form a ring, surrounding and connecting the periphery of the blasting surface 211. The thickness of the blasting surface 211 is T, the thickness of the notched section 212 is T1, and the thickness of the adhesion section 213 is T2, satisfying: T2 / T1≥1.1, and T2≤T. Among them, the values ​​of T, T1 and T2 can be measured by tools such as vernier calipers, laser rangefinders, and digital measuring instruments. It can be understood that the bursting surface 211 in the main body 21 is used as a structure for opening the explosion-proof valve 20. It is connected to other structures through the notched section 212 and the adhesive section 213. When the gas pressure inside the battery is too high, the bursting surface 211 will be squeezed, so that the notched section 212 connected to the bursting surface 211 is destroyed. Since the thickness T2 of the adhesive section 213 and the thickness T1 of the notched section 212 satisfy: T2 / T1≥1.1, when the gas pressure reaches the size of destroying the notched section 212, the adhesive section 213 cannot be destroyed. Therefore, the adhesive section 213 still connects the bursting surface 211 with other structures on the explosion-proof valve 20 to prevent the bursting surface 211 from flying out. At this time, a part of the bursting surface 211 loses the constraint of the notched section 212, and will be lifted up by the gas with a higher pressure inside the battery, so that the bursting surface 211 is opened, the space inside the shell is connected to the external environment, and the gas inside the shell is released to the outside world, achieving the effect of pressure relief and temperature reduction. Since the thickness T2 of the adhesion section 213 and the thickness T of the bursting surface 211 satisfy: T2≤T, the thickness T2 of the adhesion section 213 is less than or equal to the thickness T of the bursting surface 211, which is conducive to the processing and molding of the explosion-proof valve 20 through the mold. Otherwise, it will increase the manufacturing difficulty of the production mold, which is not conducive to the processing and molding of the explosion-proof valve 20. When the battery meets the conditions of T2 / T1≥1.1 and T2≤T, the explosion-proof valve 20 is subjected to a burst test, and the test pressure is set according to the rated pressure and design requirements of the battery explosion-proof valve 20. The test pressure should be slightly higher than the rated pressure of the explosion-proof valve 20 to ensure that the explosion-proof valve 20 can work normally; connect the test equipment to the battery explosion-proof valve 20 to ensure that the connection is tight and reliable without leakage; gradually increase the test pressure until the set test pressure is reached. During the test, pay attention to the working status of the explosion-proof valve 20 and any abnormal conditions. The test results of the embodiment and comparative example are as follows:

[0047]

[0048]

[0049] See also Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 and Figure 8 In combination with the above embodiments, in some embodiments, the main body 21 further includes an outer ring 214. The outer ring 214 is arranged around the blasting surface 211 and is connected to the connecting portion 22. The notched segment 212 and the adhesive segment 213 are located between the outer ring 214 and the blasting surface 211. The outer ring 214 is connected to the blasting surface 211 through the notched segment 212 and the adhesive segment 213. The thickness of the outer ring 214 is B, which satisfies: T≤B≤1.5mm. It can be understood that the outer ring 214 of the main body 21 is arranged around the notched segment 212 and the adhesive segment 213 and is connected to the notched segment 212 and the adhesive segment 213. The notched segment 212 and the adhesive segment 213 are connected to form an annular structure and are arranged between the outer ring 214 and the blasting surface 211. The notched segment 212 and the adhesive segment 213 fill the gap between the outer ring 214 and the blasting surface 211. The thickness of the outer ring 214 is B, and the thickness of the bursting surface 211 is T, which satisfies: T≤B≤1.5mm. Under this condition, the outer ring 214 has good rigidity, can withstand a certain external force, and improves the ability to resist deformation. The purpose of satisfying T≤B is to make the outer ring 214 more resistant to deformation than the bursting surface 211, and to ensure that when the explosion-proof valve 20 is squeezed by the internal gas of the battery, the bursting surface 211 can be broken and opened normally, and the state of the outer ring 214 remains unchanged. The purpose of satisfying B≤1.5mm is to facilitate the processing and forming of the outer ring 214 while meeting the rigidity requirements of the outer ring 214, reduce the material consumption of the outer ring 214, and reduce the processing cost.

[0050] See also Figure 2 , Figure 3 , Figure 4 , Figure 5In combination with the above embodiments, in some embodiments, the orthographic projection area of ​​the main body 21 on the plane perpendicular to the thickness direction X is S, and the orthographic projection area of ​​the bursting surface 211 on the plane perpendicular to the thickness direction X is S1, which satisfies: 50%≤S1 / S≤95%. When S1 / S is within the range of 50% to 95%, the bursting surface 211 can be opened in time when it is squeezed by the preset pressure inside the battery, ensuring that the gas inside the battery can be released to the external environment in time, thereby improving the safety of the battery. Among them, S1 and S can be measured by a caliper: the corresponding size of the corresponding projection can be directly measured using a caliper, or the corresponding size of the corresponding structure can be directly measured, and then the corresponding area is obtained by calculation; it can also be measured by a three-dimensional scanner, which can obtain three-dimensional data of the corresponding projection or structure, and then the area of ​​the corresponding projection or structure is obtained by calculation. S1 / S is in the range of 50% to 95%, and can be any value among 50%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or any range between two values. When it is within this range, the thermal spread of the battery is triggered by heating to simulate the thermal runaway state of the battery, and the opening of the explosion-proof valve 20 is observed to see whether the valve can be opened normally when the preset opening pressure is reached. The test results of the embodiment and the comparative example are as follows:

[0051]

[0052] From the above table, it can be seen that when the ratio of the orthographic projection area S1 of the explosion surface 211 on the plane perpendicular to the thickness direction X to the orthographic projection area S of the main body 21 on the plane perpendicular to the thickness direction X is in the range of 50% to 95%, the battery is in a thermal runaway state, and the explosion-proof valve 20 can open the valve normally to release the pressure inside the battery in time to prevent the battery from exploding and ensure the safety of the battery.

[0053] See also Figure 4 , Figure 5 and Figure 6In combination with the above embodiments, in some embodiments, the thickness of the welding portion 23 is L, and the thickness of the bursting surface 211 is T, which satisfies: 15% ≤ T / L ≤ 70%. When T / L is within the range of 15% to 70%, while facilitating the processing of the explosion-proof valve 20, the welding portion 23 and the bursting surface 211 can have a certain rigidity, thereby avoiding the concave situation of the explosion-proof valve 20 and affecting the opening pressure of the explosion-proof valve 20. Among them, the sizes of T and L can be measured by measuring tools such as vernier calipers and digital calipers. Within the range of 15% to 70%, T / L can be any value of 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, or a range value between any two values. When it is within this range, test whether the explosion-proof valve 20 can be processed and formed; and perform a breathing test on the explosion-proof valve 20 (the breathing test is to place the explosion-proof valve 20 in a specific test device, which can simulate the pressure changes inside the battery. By applying different pressure and temperature conditions, the response and gas release ability of the explosion-proof valve 20 under different conditions can be tested), and observe whether the explosion-proof valve 20 that meets the ratio requirements has a concave phenomenon. The test results of the embodiment and the comparative example are as follows:

[0054]

[0055] It can be seen from the above table that when the ratio of the thickness T of the bursting surface 211 to the thickness L of the welding portion 23 is in the range of 15% to 70%, it will not affect the normal processing of the explosion-proof valve 20. At the same time, when the explosion-proof valve 20 is subjected to a breathing test, the explosion-proof valve 20 does not appear concave. When T / L is in the range of 15% to 70%, the explosion-proof valve 20 has good anti-deformation ability, and when the preset pressure is reached inside the battery, the normal opening of the explosion-proof valve 20 can be guaranteed.

[0056] A single cell battery refers to an independent battery unit that can generate electricity to supply electronic equipment or systems. A single cell battery usually has a shell containing components such as a positive electrode, a negative electrode, an electrolyte and a diaphragm. The shell has a receiving cavity, and the positive electrode, the negative electrode, the electrolyte and the diaphragm are arranged in the receiving cavity; it also includes the cover plate assembly mentioned above, which is connected to the shell and covers the receiving cavity, so that the structure inside the receiving cavity has a good working environment and is not affected by external factors.

[0057] A battery pack, including the above-mentioned single cell, or the above-mentioned cover assembly. The battery pack is a whole composed of multiple single cells, usually including battery cells, battery management system (BMS), connectors, protective shell and other components. Its main function is to provide higher voltage, capacity and energy density to meet the needs of various applications. Battery packs are usually used in electric vehicles, drones, portable electronic devices, energy storage systems, emergency power supplies and other fields.

[0058] 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.

[0059] The cover plate assembly, single cell and battery pack provided in the embodiments of the present application are introduced in detail above, and the principles and implementation methods of the present application are explained by using specific examples. 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 solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A cover plate assembly, characterized in that: include: The cover plate body has a through hole; an explosion-proof valve connected to the cover body and sealing the through hole, the explosion-proof valve comprising a main body, a connecting part and a welding part, the main body protruding along the thickness direction of the cover body, and a surface on one side of the thickness direction is an arc surface, the connecting part is arranged around the periphery of the main body and connected to the main body, the welding part is arranged around the periphery of the connecting part and is respectively connected to the connecting part and the cover body; The angle between the connecting portion and the welding portion is a, which satisfies: 90°≤a≤175°.

2. The cover plate assembly according to claim 1, characterized in that: The thickness of the welding portion is L, which satisfies 0.3 mm ≤ L ≤ 1 mm.

3. The cover plate assembly according to claim 1, characterized in that: The thickness of the welding portion is L, and the thickness of the connecting portion is L1, which satisfies: 0.15 mm ≤ L1 ≤ L.

4. The cover plate assembly according to claim 1, characterized in that: The maximum dimension of the explosion-proof valve in the thickness direction of the cover plate body is H, and the thickness of the welding portion is L, which satisfies: 0mm≤H-1.1L≤5mm.

5. The cover plate assembly according to claim 1, characterized in that: The main body comprises a bursting surface, a notched section and an adhesive section, wherein the notched section is connected to the periphery of the bursting surface, the adhesive section is connected to the periphery of the bursting surface, and two ends of the adhesive section are respectively connected to two ends of the notched section; The thickness of the bursting surface is T, the thickness of the notched section is T1, and the thickness of the adhesion section is T2, satisfying: T2 / T1≥1.1, and T2≤T.

6. The cover plate assembly according to claim 5, characterized in that: The main body also includes: The outer ring is arranged around the blasting surface and connected to the connecting portion. The notched segment and the adhesion segment are located between the outer ring and the blasting surface. The outer ring is connected to the blasting surface through the notched segment and the adhesion segment. The thickness of the outer ring is B, satisfying: T≤B≤1.5mm.

7. The cover plate assembly according to claim 5, characterized in that: The orthographic projection area of ​​the main body on the plane perpendicular to the thickness direction is S, and the orthographic projection area of ​​the blasting surface on the plane perpendicular to the thickness direction is S1, satisfying: 50%≤S1 / S≤95%.

8. The cover plate assembly according to claim 5, characterized in that: The thickness of the welding portion is L, and the thickness of the bursting surface is T, which satisfies: 15%≤T / L≤70%.

9. A single cell battery, characterized in that: include: A housing having a receiving cavity; The cover plate assembly according to any one of claims 1 to 8, wherein the cover plate assembly is connected to the shell and covers the accommodating cavity.

10. A battery pack, characterized in that: The invention comprises the single battery as claimed in claim 9, or the cap plate assembly as claimed in any one of claims 1 to 8.

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