Cover plate assembly and single battery

Abstract

The invention discloses a cover plate assembly and a single battery, and belongs to the technical field of batteries, the cover plate assembly comprises: a cover plate body having an explosion-proof hole; the explosion-proof valve covers and seals the explosion-proof hole, the explosion-proof valve comprises a connecting part, a first thinning part and a second thinning part, the first thinning part is connected to the second thinning part in a surrounding mode, and a nick is arranged at the connecting position of the first thinning part and the second thinning part. Through the arrangement of the boss, the electrode assembly and the explosion-proof hole can be separated, the explosion-proof hole is prevented from being blocked by the electrode assembly when the battery is subjected to thermal runaway, and meanwhile, the boss is provided with the first through hole, the second through hole and the circulation cavity, so that gas in the battery can conveniently pass through the first through hole, the second through hole and the circulation cavity to impact the explosion-proof valve; the explosion-proof valve can be opened to release pressure, even if the electrode assembly moves towards the direction of the explosion-proof valve, only the second through hole is blocked, gas still enters the circulation cavity through the first through hole, the explosion-proof valve cannot be blocked, and normal exhaust of the explosion-proof valve is guaranteed.

Description

Technical Field

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

[0002] The function of the explosion-proof valve is to open when the internal pressure of the battery exceeds the safety limit, allowing gas to be released from the battery to reduce the internal pressure. This can effectively prevent the battery from exploding and protect the safety of the surrounding environment and users. However, when the battery is in thermal runaway, the electrode assembly inside the battery will move toward the explosion-proof valve, blocking the explosion-proof valve and affecting normal exhaust. Summary of the invention

[0003] Purpose of the invention: An embodiment of the present application provides a cover plate assembly, aiming to overcome the technical problem that when a battery has thermal runaway, the internal electrode assembly will move toward the explosion-proof valve and block the explosion-proof valve; another purpose of an embodiment of the present application is to provide a single cell.

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

[0005] The cover body has explosion-proof holes;

[0006] An explosion-proof valve, covering the explosion-proof hole, the explosion-proof valve comprises a connecting portion, a first thinned portion and a second thinned portion, the first thinned portion is connected to the second thinned portion in a surrounding manner, a notch is provided at the connection between the first thinned portion and the second thinned portion, the connecting portion is connected to the first thinned portion in a surrounding manner, and is connected to the cover plate body;

[0007] A boss, located on a side of the explosion-proof valve facing the electrode assembly and connected to the cover body, the boss includes a side plate portion and a bottom plate portion, the side plate portion is connected to the cover body, the bottom plate portion is connected to a side of the side plate portion away from the cover body, and is enclosed with the side plate portion to form a flow cavity, the side plate portion has a first through hole, the bottom plate portion has a second through hole, and the first through hole and the second through hole are both connected to the flow cavity;

[0008] The cover plate assembly satisfies: 0.5≤S3 / (S1+S2)≤2;

[0009] Wherein, S1 is the total area of ​​the first through holes, S2 is the total area of ​​the second through holes, and S3 is the area of ​​the second thinned portion.

[0010] In some embodiments, the thickness of the cover body is a, and the height of the boss is b, satisfying: 0<b / a≤2;

[0011] Among them, 0.15mm≤a≤3mm.

[0012] In some embodiments, the cover body is made of steel, and the thickness a of the cover body satisfies: 0.15mm≤a≤1mm; or, the cover body is made of aluminum, and the thickness a of the cover body satisfies: 1mm≤a≤3mm.

[0013] In some embodiments, the included angle between the side plate portion and the bottom plate portion is A, satisfying: 90°<A<180°.

[0014] In some embodiments, the inner side surface and the outer side surface of the side plate portion are arc surfaces, and the angle between the tangent line at any point on the arc surface and the cover body is B, which satisfies: 90°<B<180°.

[0015] In some embodiments, the notch is disposed around the second thinned portion and is located on a side of the explosion-proof valve away from the boss.

[0016] In some embodiments, the explosion-proof valve is disposed on a side of the cover body facing away from the boss.

[0017] In some embodiments, the cover body has a placement groove connected to the explosion-proof hole, the placement groove is located on a side of the cover body away from the boss, and at least a portion of the connecting portion is disposed in the placement groove.

[0018] In some embodiments, the cover body and the boss are an integrated structure.

[0019] A single battery, comprising:

[0020] A housing having a receiving cavity;

[0021] An electrode assembly is disposed in the accommodating cavity;

[0022] As described in any one of the above-mentioned cover plate assemblies, the cover plate assembly covers the accommodating cavity and is connected to the shell.

[0023] Beneficial effect: The cover assembly of the embodiment of the present application includes: a cover body, which has an explosion-proof hole; an explosion-proof valve, which covers the explosion-proof hole, the explosion-proof valve includes a connecting portion, a first thinning portion and a second thinning portion, the first thinning portion is connected to the second thinning portion in a surrounding manner, and a notch is provided at the connection between the first thinning portion and the second thinning portion, the connecting portion is connected to the first thinning portion in a surrounding manner, and is connected to the cover body; a boss, which is located on the side of the explosion-proof valve facing the electrode assembly and is connected to the cover body, the boss includes a side plate portion and a bottom plate portion, the side plate portion is connected to the cover body, the bottom plate portion is connected to the side of the side plate portion away from the cover body, and is enclosed with the side plate portion to form a flow cavity, the side plate portion has a first through hole, the bottom plate portion has a second through hole, and the first through hole and the second through hole are both connected to the flow cavity; the cover assembly satisfies: 0.5≤S3 / (S1+S2)≤2; wherein S1 is the total area of ​​the first through hole, S2 is the total area of ​​the second through hole, and S3 is the area of ​​the second thinning portion. By setting the boss, the electrode assembly and the explosion-proof hole can be separated to prevent the electrode assembly from clogging the explosion-proof hole when the battery has thermal runaway. At the same time, the first through hole, the second through hole and the flow cavity are set on the boss to facilitate the gas inside the battery to impact the explosion-proof valve through the first through hole, the second through hole and the flow cavity, so that the explosion-proof valve can be opened to release pressure. Even if the electrode assembly moves toward the direction of the explosion-proof valve, only the second through hole will be blocked, and the gas will still enter the flow cavity through the first through hole, and will not cause clogging of the explosion-proof valve, thereby ensuring that the explosion-proof valve can be exhausted normally. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] 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.

[0025] Figure 1 This is a front cross-sectional view of the cover plate assembly of an embodiment of the present application;

[0026] Figure 2 A three-dimensional diagram of a cover plate assembly according to an embodiment of the present application;

[0027] Figure 3 This is a three-dimensional diagram of an explosion-proof valve according to an embodiment of the present application;

[0028] Figure 4 It is a front cross-sectional view of the boss of the embodiment of the present application, wherein the inner surface of the boss is a plane;

[0029] Figure 5 It is a front view and cross section of the boss of the embodiment of the present application, wherein the inner surface of the boss is a curved surface;

[0030] Figure 6This is a structural schematic diagram of a connection form between the explosion-proof valve and the cover plate body in an embodiment of the present application;

[0031] Figure 7 This is a structural schematic diagram of another connection form between the explosion-proof valve and the cover plate body in an embodiment of the present application;

[0032] Figure 8 This is a schematic diagram of the structure when the electrode assembly and the boss abut against each other in the embodiment of the present application;

[0033] Figure markings: 10-cover body; 11-explosion-proof hole; 12-placing groove; 20-explosion-proof valve; 21-connecting part; 22-first thinning part; 23-second thinning part; 24-notch; 30-boss; 31-side plate; 311-first through hole; 32-bottom plate; 321-second through hole; 33-circulation cavity; 40-electrode assembly. DETAILED DESCRIPTION

[0034] 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.

[0035] 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.

[0036] The battery has an explosion-proof valve, which automatically opens when the pressure inside the battery exceeds the preset opening pressure of the explosion-proof valve, thereby releasing the pressure inside the battery and ensuring the safe operation of the battery. When the explosion-proof valve opens, the battery is generally in an abnormal state (such as thermal runaway), and a large amount of high-temperature gas will be generated inside the battery, which will be discharged to the outside through the explosion-proof valve. At present, the explosion-proof valve is separated from the electrode assembly inside the battery by plastic, which can ensure insulation and smooth exhaust. When the explosion-proof valve is opened, it can also be exhausted normally. As the gas production increases, the pressure inside the battery shell increases, and the temperature increases, the plastic between the explosion-proof valve and the electrode assembly will melt, thereby losing its process function. The electrode assembly inside the battery shell will move toward the side of the explosion-proof valve, blocking the explosion-proof valve hole, affecting the normal exhaust of the explosion-proof valve, and then the internal air pressure will rise suddenly, causing the entire cavity to burst, and then more serious consequences will occur.

[0037] 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.

[0038] See also Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 8 In an embodiment of the present application, the cover plate assembly includes a cover plate body 10 , an explosion-proof valve 20 and a boss 30 .

[0039] The cover body 10 has an explosion-proof hole 11, which is arranged along the thickness direction of the cover body 10, and can connect the space inside the battery shell with the external environment. The explosion-proof valve 20 covers the explosion-proof hole 11, and the explosion-proof valve 20 includes a connecting portion 21, a first thinning portion 22 and a second thinning portion 23. The first thinning portion 22 is connected to the second thinning portion 23 in a circumferential manner, and a notch 24 is provided at the connection between the first thinning portion 22 and the second thinning portion 23. The connecting portion 21 is connected to the first thinning portion 22 in a circumferential manner and is connected to the cover body 10. The explosion-proof valve 20 can be arranged inside the explosion-proof hole 11 or outside the explosion-proof hole 11, as long as it can cover the explosion-proof hole 11. The explosion-proof valve 20 is connected to the cover body 10 through the connecting portion 21 thereon, so that the explosion-proof valve 20 can be fixed as a whole on the cover body 10. A first thinning portion 22 and a second thinning portion 23 are provided on the explosion-proof valve 20. The dimensions of both in the thickness direction of the cover body 10 are smaller than the dimension of the connecting portion 21 in the thickness direction. At the same time, a notch 24 is provided at the connection between the first thinning portion 22 and the second thinning portion 23, so that the thickness dimension of the connection between the first thinning portion 22 and the second thinning portion 23 is smaller than the thickness dimension of the first thinning portion 22 and the second thinning portion 23. When an abnormality occurs in the battery and the internal pressure reaches a preset pressure value, the gas inside the battery will squeeze the explosion-proof valve 20. Since the connection between the first thinning portion 22 and the second thinning portion 23 is relatively weak, it is easy to be damaged when squeezed by the internal gas of the battery, which will cause the second thinning portion 23 to be at least partially separated from the first thinning portion 22, so that the explosion-proof valve 20 opens, and the gas inside the battery can be discharged to the outside from the position where the second thinning portion 23 is separated from the first thinning portion 22, thereby achieving pressure relief inside the battery.

[0040] The boss 30 is located on the side of the explosion-proof valve 20 facing the electrode assembly 40, and is connected to the cover body 10. The boss 30 includes a side plate portion 31 and a bottom plate portion 32. The side plate portion 31 is connected to the cover body 10. The bottom plate portion 32 is connected to the side of the side plate portion 31 away from the cover body 10, and is enclosed with the side plate portion 31 to form a flow cavity 33. The side plate portion 31 has a first through hole 311, and the bottom plate portion 32 has a second through hole 321. The first through hole 311 and the second through hole 321 are both connected to the flow cavity 33. It can be understood that the boss 30 can be set on the side of the cover body 10 facing the electrode assembly 40, and the boss 30 protrudes in the direction of the electrode assembly 40. The inside of the boss 30 is formed with a flow cavity 33. The flow cavity 33 can be directly connected to the explosion-proof hole 11, and can also be connected to the explosion-proof hole 11 when the explosion-proof valve 20 breaks. It can be set according to the position of the explosion-proof valve 20. One or more first through holes 311 are provided on the side plate 31 of the boss 30, which are used to connect the circulation chamber 33 with the space inside the battery shell, and one or more second through holes 321 are provided on the bottom plate 32 of the boss 30, which are also used to connect the circulation chamber 33 with the space inside the battery shell. When the battery is abnormal and more gas is generated inside, these gases can enter the circulation chamber 33 through the first through hole 311 and the second through hole 321, so that the explosion-proof valve can be squeezed to open the explosion-proof valve for pressure relief. When the electrode assembly 40 moves toward the direction of the boss 30 under the action of the gas, the second through hole 321 on the bottom plate 32 may be covered, so that the second through hole 321 is blocked, but the gas inside the battery can still circulate through the first through hole 311 on the side plate 31, enter the circulation chamber 33, and then be discharged to the outside, which will not affect the pressure relief inside the battery, and ensure that the explosion-proof valve can be exhausted normally.

[0041] The cover plate assembly satisfies: 0.5≤S3 / (S1+S2)≤2; wherein S1 is the total area of ​​the first through holes 311, S2 is the total area of ​​the second through holes 321, and S3 is the area of ​​the second thinned portion 23. S3 / (S1+S2) is generally in the range of 0.5 to 2, and S3 / (S1+S2) can be any value among 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, or a range between any two values. If the first through hole 311 and the second through hole 321 are regular shapes, such as circles, rectangles, etc., S1, S2 and S3 can be measured by a caliper: the corresponding size of the through hole can be directly measured using a caliper, and then the area of ​​the through hole can be obtained by calculation; if the first through hole 311 and the second through hole 321 are irregular shapes, they can be measured by a three-dimensional scanner, which can obtain three-dimensional data of the corresponding through holes, and then the area of ​​the through hole can be obtained by calculation. It should be noted that the performance of the boss 30 structure in the embodiment of the present application is represented by the battery state under the condition of battery heat spread. During the specific test, the battery heat spread was triggered by heating. Each scheme was tested with 5 samples to observe the battery state and valve opening status, and at the same time observe the integrity of the boss 30. The test results of the embodiment and the comparative example are as follows:

[0042]

[0043] It can be seen from the above table that the normal exhaust effect of the explosion-proof valve 20 can be guaranteed to a certain extent by setting the boss 30, but the exhaust effect may be weakened during long-term exhaust. It can be seen from Comparative Examples 1 and 2 that the first through hole 311 and the second through hole 321 on the boss 30 have a large area, the boss 30 itself has a low strength, and is in a normal exhaust state in the early stage of the eruption, but with the increase of gas volume and temperature, the boss 30 with insufficient strength may deform and collapse, and lose its normal exhaust function. In Comparative Example 3, the area of ​​the second thinning portion 23 is small, the area of ​​the first through hole 311 and the second through hole 321 is large, and the shell cover welding connection area of ​​two of the five samples has cracks. In Comparative Examples 4 and 5, the area of ​​the first through hole 311 and the second through hole 321 is small, and the strength of the corresponding boss 30 will become higher, but the exhaust is not timely, and some battery samples have serious damage to the cover plate and cracks in the welding position around the shell and cover plate. In Examples 1 to 4, no shell explosion was found, and no cracks were found at the connection between the shell and the cover plate, and the valve opening state was good. Therefore, by satisfying 0.5≤S3 / (S1+S2)≤2, the normal opening and exhaust of the explosion-proof valve 20 can be further guaranteed, so that the battery shell is intact and the safety of the battery during use is improved.

[0044] See also Figure 1 and Figure 4 , combined with the above embodiments, in some embodiments, the thickness of the cover body 10 is a, and the height of the boss 30 is b, which satisfies: 0<b / a≤2; wherein, 0.15mm≤a≤3mm. It can be understood that the thickness of the cover body 10 is between 0.15mm and 3mm, which can ensure the use strength of the cover body 10, and at the same time, it can also save the amount of material used for the cover body 10 and reduce the processing cost of the battery. Since the boss 30 and the cover body 10 are generally an integrated structure, the boss 30 can be stamped by the cover body 10. When the ratio of the height b of the boss 30 to the thickness a of the cover body 10 satisfies 0<b / a≤2, the processing and forming of the boss 30 can be facilitated. The height of the boss 30 is at most twice the thickness of the cover body 10, which can ensure that the boss 30 has a certain use strength. If it exceeds twice, the stamped boss 30 is prone to hardening and cracking.

[0045] See also Figure 1 and Figure 4 In combination with the above embodiments, in some embodiments, the cover body 10 is made of steel, and the thickness a of the cover body 10 satisfies: 0.15mm≤a≤1mm; or, the cover body 10 is made of aluminum, and the thickness a of the cover body 10 satisfies: 1mm≤a≤3mm. It can be understood that when the cover body 10 is made of steel (such as SUS304, SUS316, etc.), since the steel material has a high strength, the thickness of the cover body 10 can be in the range of 0.15mm to 1mm, and can be set thinner, saving materials, reducing the processing cost of the cover body 10, and at the same time ensuring the use strength of the cover body 10.

[0046] See also Figure 1 and Figure 4 In combination with the above embodiments, in some embodiments, the angle between the side plate portion 31 and the bottom plate portion 32 is A, which satisfies: 90°<A<180°. It can be understood that the angle between the side plate portion 31 and the bottom plate portion 32 is between 90° and 180°, so that the side plate portion 31 is in an inclined state. When the boss 30 is stamped and formed, since the boss 30 is wrapped on the mold and the angle between the side plate portion 31 and the bottom plate portion 32 is an obtuse angle, it is convenient to remove the boss 30 from the mold during demolding, so as to avoid the situation where the angle between the side plate portion 31 and the bottom plate portion 32 is too small and the boss 30 cannot be demolded.

[0047] See also Figure 1 and Figure 5In combination with the above embodiments, in some embodiments, the inner side and outer side of the side plate portion 31 are arc surfaces, and the angle between the tangent at any point on the arc surface and the cover plate body 10 is B, which satisfies: 90°<B<180°. It can be understood that the inner surface and outer surface of the side plate portion 31 can be formed by splicing multiple planes, or multiple arc surfaces, or directly formed by the entire arc surface. If the inner surface and outer surface of the side plate portion 31 are arc surfaces, the angle B between the tangent at any point on the arc surface and the cover plate body 10 satisfies: 90°<B<180°, by setting the inner surface and outer surface of the side plate portion 31 as arc surfaces, the area of ​​the inner surface and outer surface of the side plate portion 31 can be increased, so that more first through holes 311 can be set on the side plate portion 31, or the area of ​​the first through hole 311 can be set larger, which is conducive to the discharge of gas inside the battery when the battery is abnormal.

[0048] See also Figure 3 and Figure 4 In combination with the above embodiments, in some embodiments, the notch 24 is arranged around the second thinning portion 23 and is located on the side of the explosion-proof valve 20 away from the boss 30. It can be understood that the notch 24 is arranged between the first thinning portion 22 and the second thinning portion 23, and can be used to adjust the critical pressure value of the explosion of the explosion-proof valve 20. The depth of the notch 24 is different, and the critical pressure value of the explosion of the explosion-proof valve 20 is also different (the critical pressure value of the explosion of the explosion-proof valve 20 refers to the minimum pressure value required for the explosion. When the pressure inside the battery is greater than the critical pressure value of the explosion, the explosion-proof valve 20 will open the valve to exhaust. For different systems, the critical explosion value of the explosion-proof valve 20 is also different. The ternary system has PA, and the iron-lithium system has PB, which satisfies: 0.7MPa≤PA≤1.1MPa, 0.4MPa≤PB≤0.8Mpa). The notch 24 is located on the side of the explosion-proof valve 20 away from the boss 30. When an abnormality occurs in the battery, the gas generated inside will impact the second thinning portion 23 on the explosion-proof valve 20. Since the opening of the notch 24 is in the same direction as the impact direction of the gas inside the battery, when the gas impacts the second thinning portion 23, the second thinning portion 23 slightly bulges upward, and a portion of the outer circumference of the second thinning portion 23 can be filled into the inside of the notch 24, allowing the second thinning portion 23 to deform to a greater extent, so that when an abnormality occurs in the battery, the second thinning portion 23 is more easily separated from the first thinning portion 22. If the opening of the notch 24 is opened toward the boss 30, when the second thinning portion 23 is impacted by gas, the degree of upward bulging deformation is small (there is not much space for the second thinning portion 23 to deform), which will increase the difficulty of separating the second thinning portion 23 from the first thinning portion 22.

[0049] See also Figure 6In combination with the above embodiments, in some embodiments, the explosion-proof valve 20 is arranged on the side of the cover body 10 away from the boss 30. It is understandable that when the explosion-proof valve 20 is fixed, it can be arranged on the side of the cover body 10 away from the boss 30, that is, it is arranged on the top of the cover body 10, and the explosion-proof valve 20 and the cover body 10 can be welded by penetration welding (the explosion-proof valve 20 and the cover body 10 are welded by penetrating the connection part 21 of the explosion-proof valve 20). The explosion-proof valve 20 is located outside the explosion-proof hole 11, which is convenient for welding and fixing the explosion-proof valve 20 and reducing the difficulty of operation. When this connection method is adopted, the cover body 10 is preferably made of steel.

[0050] See also Figure 7 In combination with the above embodiments, in some embodiments, the cover body 10 has a placement groove 12 connected to the explosion-proof hole 11, the placement groove 12 is located on the side of the cover body 10 away from the boss 30, and at least part of the connecting portion 21 is arranged in the placement groove 12. It can be understood that the explosion-proof valve 20 can be partially arranged inside the explosion-proof hole 11 when fixed. A placement groove 12 is opened on the side of the cover body 10 away from the boss 30, the placement groove 12 is arranged around the explosion-proof hole 11, and is connected to the explosion-proof hole 11, the explosion-proof valve 20 is placed in the placement groove 12 and the explosion-proof hole 11, at least part of the connecting portion 21 of the explosion-proof valve 20 is arranged in the placement groove 12, and the connecting portion 21 and the cover body 10 are welded. This structure can reduce the space occupied by the battery, making the structure more compact, and can also play a certain protective role for the explosion-proof valve 20, avoiding deformation caused by foreign objects and affecting the normal use of the explosion-proof valve 20. When this connection method is adopted, the cover body 10 is preferably made of aluminum, which is convenient for processing and forming the placement groove 12.

[0051] See also Figure 1 In combination with the above embodiments, in some embodiments, the cover body 10 and the boss 30 are an integrated structure. It is convenient to process the boss 30 by stamping, saving steps and reducing costs. At the same time, the cover body 10 and the boss 30 are integrally formed, which can improve the connection strength between the cover body 10 and the boss 30 and improve the stability of the boss 30.

[0052] A single cell battery comprises a shell, an electrode assembly 40 and any one of the above-mentioned cover plate assemblies. The shell has a receiving cavity. The electrode assembly 40 is arranged in the receiving cavity. The cover plate assembly covers the receiving cavity and is connected to the shell. A single cell battery is an independent battery unit that can generate electrical energy for use in electronic equipment or systems. A single cell battery usually has an electrode assembly 40 including a positive electrode, a negative electrode, an electrolyte and a diaphragm, and also comprises a shell, the shell has a receiving cavity, and the electrode assembly 40 is arranged in the receiving cavity. The single cell battery also comprises a cover plate assembly, 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.

[0053] 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.

[0054] The cover plate assembly and single cell 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 solution deviate from the scope of the technical solution of the embodiments of the present application.

Claims

1. A cover plate assembly, characterized in that: include: The cover body has explosion-proof holes; An explosion-proof valve, covering the explosion-proof hole, the explosion-proof valve comprises a connecting portion, a first thinned portion and a second thinned portion, the first thinned portion is connected to the second thinned portion in a surrounding manner, a notch is provided at the connection between the first thinned portion and the second thinned portion, the connecting portion is connected to the first thinned portion in a surrounding manner, and is connected to the cover plate body; A boss, located on a side of the explosion-proof valve facing the electrode assembly and connected to the cover body, the boss includes a side plate portion and a bottom plate portion, the side plate portion is connected to the cover body, the bottom plate portion is connected to a side of the side plate portion away from the cover body, and is enclosed with the side plate portion to form a flow cavity, the side plate portion has a first through hole, the bottom plate portion has a second through hole, and the first through hole and the second through hole are both connected to the flow cavity; The cover plate assembly satisfies: 0.5≤S3 / (S1+S2)≤2; Wherein, S1 is the total area of ​​the first through holes, S2 is the total area of ​​the second through holes, and S3 is the area of ​​the second thinned portion.

2. The cover plate assembly according to claim 1, characterized in that: The thickness of the cover body is a, and the height of the boss is b, which satisfies: 0<b / a≤2; Among them, 0.15mm≤a≤3mm.

3. The cover plate assembly according to claim 2, characterized in that: The cover plate body is made of steel, and the thickness a of the cover plate body satisfies: 0.15mm≤a≤1mm; or, the cover plate body is made of aluminum, and the thickness a of the cover plate body satisfies: 1mm≤a≤3mm.

4. The cover plate assembly according to claim 1, characterized in that: The included angle between the side plate portion and the bottom plate portion is A, which satisfies: 90°<A<180°.

5. The cover plate assembly according to claim 4, characterized in that: The inner side surface and the outer side surface of the side plate portion are arc surfaces, and the angle between the tangent line at any point on the arc surface and the cover plate body is B, which satisfies: 90°<B<180°.

6. The cover plate assembly according to claim 1, characterized in that: The notch is arranged around the second thinned portion and is located on a side of the explosion-proof valve away from the boss.

7. The cover plate assembly according to claim 1, characterized in that: The explosion-proof valve is arranged on a side of the cover plate body away from the boss.

8. The cover plate assembly according to claim 1, characterized in that: The cover body has a placement groove communicated with the explosion-proof hole, the placement groove is located on a side of the cover body away from the boss, and at least a part of the connecting portion is arranged in the placement groove.

9. The cover plate assembly according to claim 1, characterized in that: The cover plate body and the boss are an integrated structure.

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

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