Cover plate assembly, battery cell and secondary battery

Abstract

The utility model provides a cover plate assembly, a battery cell and a secondary battery, the cover plate assembly is used for sealing the battery cell, and the cover plate assembly comprises: a cover plate body provided with an explosion-proof hole; the explosion-proof sheet is mounted at one end, close to the interior of the battery cell, of the explosion-proof hole, when the internal pressure of the battery cell reaches a threshold value, the explosion-proof sheet is folded and opened along one edge of the explosion-proof sheet, and an included angle between the folded explosion-proof sheet and the inner wall of the explosion-proof hole is alpha; the high-temperature-resistant sheet is arranged on the surface, far away from the interior of the battery cell, of the anti-explosion sheet, the thickness of the high-temperature-resistant sheet is e, before the anti-explosion sheet is turned over, the distance between the edge of the high-temperature-resistant sheet and the inner wall of the anti-explosion hole is L, and L is larger than or equal to e / tan alpha. The cover plate assembly, the battery cell and the secondary battery provided by the utility model are simple in structure and convenient to manufacture, normal opening of the explosion-proof valve is ensured while heat spreading is prevented, and the safety of the battery is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a cover plate assembly, a battery cell and a secondary battery. BACKGROUND

[0002] With the continuous development of the new energy industry, higher requirements are put forward for batteries. The cover plate assembly, as an important component of the battery structure, has also undergone several developments. The current cover plate assembly is provided with an explosion-proof valve structure, which can effectively relieve pressure when the battery cell is in thermal runaway. Some technologies set high-temperature-resistant sheets to improve the flame retardance of the explosion-proof valve, but the high-temperature-resistant sheets also hinder the opening of the explosion-proof valve, affecting the pressure relief effect. Therefore, there is an urgent need for a cover plate assembly that ensures the normal opening of the explosion-proof valve. CONTENT OF THE UTILITY MODEL

[0003] Therefore, the purpose of the present application is to provide a cover plate assembly, a battery cell and a secondary battery to solve the problems mentioned in the background art.

[0004] In a first aspect, the present application provides a cover plate assembly for enclosing a battery cell, comprising: a cover plate body provided with an explosion-proof hole; an explosion-proof sheet installed at one end of the explosion-proof hole close to the inside of the battery cell, which is folded and opened along one edge when the pressure inside the battery cell reaches a threshold value, and the included angle between the folded explosion-proof sheet and the inner wall of the explosion-proof hole is α; a high-temperature-resistant sheet provided on the surface of the explosion-proof sheet away from the inside of the battery cell, with a thickness of e, and the distance between the edge of the high-temperature-resistant sheet and the inner wall of the explosion-proof hole before the explosion-proof sheet is folded is L, L≥e / tanα.

[0005] Further, the thickness of the high-temperature-resistant sheet is less than the depth of the explosion-proof hole, and a protective sheet is installed at the end of the explosion-proof hole away from the explosion-proof sheet.

[0006] Further, 0°≤α≤30°, 0.2mm≤L≤5mm and / or 0.1mm≤e≤2mm.

[0007] Further, 0°≤α≤5°, 0.5mm≤L≤2mm, 0.3mm≤e≤1mm.

[0008] Further, a glue layer is provided between the high-temperature-resistant sheet and the explosion-proof sheet, and the orthographic projection of the high-temperature-resistant sheet on the explosion-proof sheet covers the orthographic projection of the glue layer on the explosion-proof sheet.

[0009] Further, the distance between the edge of the glue layer and the edge of the high-temperature-resistant sheet is n, 1mm≤n≤10mm; and / or the thickness of the glue layer is m, 0.03mm≤m≤0.4mm.

[0010] Further, 3mm≤n≤6mm, 0.05mm≤m≤0.15mm.

[0011] Further, the anti-explosion sheet is provided with a reinforcing rib, and the adhesive layer is provided with a avoiding hole corresponding to the reinforcing rib.

[0012] In a second aspect of the present application, an electric core is provided, comprising a shell connected with the cover plate assembly of the first aspect, and internally provided with an electrode assembly.

[0013] In a third aspect of the present application, a secondary battery is provided, comprising the electric core of the second aspect.

[0014] From the above, it can be seen that the cover plate assembly, electric core and secondary battery provided by the present application, the cover plate assembly for closing the electric core, comprising: a cover plate body provided with an anti-explosion hole; an anti-explosion sheet installed at one end of the anti-explosion hole close to the inside of the electric core, when the pressure in the electric core reaches a threshold value, the anti-explosion sheet is folded along one edge to open, the included angle between the folded anti-explosion sheet and the inner wall of the anti-explosion hole is α; a high-temperature-resistant sheet is arranged on the surface of the anti-explosion sheet away from the inside of the electric core, and the thickness of the high-temperature-resistant sheet is e, before the anti-explosion sheet is folded, the edge of the high-temperature-resistant sheet is spaced apart from the inner wall of the anti-explosion hole by a distance L; by setting L≥e / tanα, after the anti-explosion sheet is folded due to thermal runaway of the electric core, it is ensured that the anti-explosion sheet can be folded at a larger angle without being affected by the high-temperature-resistant sheet, thereby ensuring the pressure relief effect of the electric core and improving the safety performance. The cover plate assembly, electric core and secondary battery have simple structure and are easy to manufacture, can prevent heat spread while ensuring that the anti-explosion valve can be normally opened, and improve the safety of the battery. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the present application or related art, the following will briefly introduce the drawings needed to be used in the embodiments or related art descriptions. Obviously, the drawings in the following description are only embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0016] Figure 1 It is an explosion structure schematic diagram of a cover plate assembly in an embodiment of the present application;

[0017] Figure 2 It is a cross-sectional schematic diagram of the anti-explosion sheet after folding in an embodiment of the present application;

[0018] Figure 3 It is a cross-sectional schematic diagram of the anti-explosion sheet before folding in an embodiment of the present application;

[0019] Figure 4 It is a top view structural schematic diagram of the anti-explosion hole in an embodiment of the present application;

[0020] Figure 5 FIG. 1 is a schematic diagram of a structure of a high-temperature-resistant sheet and a glue layer in an embodiment of the present application;

[0021] Figure 6 FIG. 2 is a schematic diagram of another structure of a high-temperature-resistant sheet and a glue layer in an embodiment of the present application;

[0022] Figure 7 FIG. 3 is a schematic diagram of a rupture disc in an embodiment of the present application.

[0023] The reference signs are as follows: 1, cover plate body; 1-1, explosion-proof hole; 1-2, liquid injection hole; 2, rupture disc; 2-1, score; 3, high-temperature-resistant sheet; 4, protective sheet; 5, glue layer; 5-1, avoiding hole; 6, upper insulating piece; 7, lower insulating piece; 8, riveting piece; 9, pole; 10, sealing ring; 11, pin. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below with reference to the embodiments and the accompanying drawings.

[0025] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should be understood as the common meanings understood by those skilled in the art to which the embodiments of the present application belong. The terms "first", "second" and similar terms used in the embodiments of the present application do not represent any order, number or importance, but are only used to distinguish different components. The terms "include" or "contain" and similar terms mean that the components or objects before the terms cover the components or objects listed after the terms and their equivalents, and do not exclude other components or objects. The terms "connect" or "connected" and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms "upper", "lower", "left", "right" and the like are only used to represent relative positional relationships, and when the absolute positions of the described objects change, the relative positional relationships may also change accordingly.

[0026] With the continuous development of the new energy industry, higher requirements are put forward for batteries. The cover plate assembly, as an important component of the battery structure, has also undergone several developments. The cover plate assembly is mainly composed of a riveting piece, a pole, a cover plate body, an upper insulating piece, a lower insulating piece, a sealing piece and the like. As an important structural component, the primary function of the cover plate assembly is to isolate the contact between the battery cell and the external air and moisture, and at the same time, the pole on the cover plate assembly can be connected with the external circuit to realize the charging and discharging function of the battery cell.

[0027] The current cover plate assembly can be provided with an explosion-proof valve structure, which can effectively release pressure when the battery cell is in thermal runaway. In the process of implementing the present application, it is found that after the battery cell is in thermal runaway, the explosion-proof valve is opened, and the substances sprayed from the explosion-proof hole can cause the melting of the explosion-proof sheet of the adjacent battery cell to a certain extent, causing the adjacent battery cell to also be in thermal runaway, leading to the inevitable heat spread of the battery cells inside the battery pack. Some technologies will set up high-temperature-resistant sheets to improve the flame retardance of the explosion-proof valve, for example, high-temperature-resistant and high-fireproof-grade materials such as mica are attached to the explosion-proof sheet to prevent the explosion-proof sheet from melting and to prevent heat spread. However, the setting of the high-temperature-resistant sheet will also hinder the turning of the explosion-proof sheet and affect the normal opening of the explosion-proof valve, thereby affecting the pressure relief effect. Therefore, there is an urgent need for a cover plate assembly that ensures the normal opening of the explosion-proof valve.

[0028] In the following, specific embodiments will be described in detail with reference to the accompanying drawings. Figures 1 to 7 The technical solutions of the present application will be described in further detail.

[0029] In some embodiments of the present application, a cover plate assembly for enclosing a battery cell is provided, comprising: a cover plate body 1 provided with an explosion-proof hole 1-1; an explosion-proof sheet 2 installed at one end of the explosion-proof hole 1-1 close to the inside of the battery cell, when the pressure inside the battery cell reaches a threshold value, the explosion-proof sheet 2 is folded along one edge to open, the included angle between the folded explosion-proof sheet 2 and the inner wall of the explosion-proof hole 1-1 is α; a high-temperature-resistant sheet 3 is arranged on the surface of the explosion-proof sheet 2 away from the inside of the battery cell, the thickness of the high-temperature-resistant sheet 3 is e, before the explosion-proof sheet 2 is folded, the distance between the edge of the high-temperature-resistant sheet 3 and the inner wall of the explosion-proof hole 1-1 is L, L≥e / tanα.

[0030] As shown in Figure 1 , it is an explosion structure schematic diagram of the cover plate assembly, the cover plate assembly comprises a cover plate body 1, the cover plate body 1 is for example an aluminum plate, and the specific limitation is not made. The cover plate body 1 can be provided with an explosion-proof hole 1-1 in the middle, when the battery cell is in thermal runaway, high-temperature gas can be discharged from the battery cell through the explosion-proof hole 1-1, to avoid explosion.

[0031] The bottom of the explosion-proof hole 1-1 is provided with an explosion-proof sheet 2, for example, an aluminum sheet, the explosion-proof sheet 2 can be connected at the explosion-proof hole 1-1 by adhesion or clamping, and the specific limitation is not made. As shown in Figure 7 , it is a structure schematic diagram of the explosion-proof sheet 2, the explosion-proof sheet 2 can form a notch 2-1, for example, a C-shaped notch, which is a weak area of the explosion-proof sheet 2, when the battery cell is in thermal runaway, the pressure inside the battery cell reaches a threshold value, which will first damage the notch 2-1, and the explosion-proof sheet (2) is folded along one edge to open, so that the explosion-proof hole 1-1 is conducted to release pressure.

[0032] As shown in Figure 2As shown in FIG. 1, the anti-explosion sheet 2 is folded before the anti-explosion sheet 2 can close the anti-explosion hole 1-1 to ensure the sealing of the battery cell.

[0033] As shown in FIG. 2, the anti-explosion sheet 2 is folded after the anti-explosion sheet 2 is connected to the bottom of the anti-explosion hole 1-1 on one side and separated from the anti-explosion hole 1-1 on the other side due to the high temperature and high pressure of thermal runaway. The anti-explosion sheet 2 is folded under the impact of the airflow, and the anti-explosion hole 1-1 is opened. The angle between the anti-explosion sheet 2 and the inner wall of the anti-explosion hole 1-1 is a, which can be set according to the pressure relief requirement, and the smaller the better. Figure 3 As shown in FIG. 3, the high-temperature-resistant sheet 3 is arranged on the anti-explosion sheet 2. The high-temperature-resistant sheet 3 is, for example, a mica sheet, which can be bonded to the anti-explosion sheet 2 without limitation. By arranging the high-temperature-resistant sheet 3, the anti-explosion sheet 2 can be protected, and the anti-explosion sheet 2 of the battery cell can also be melted and cause thermal runaway when the adjacent battery cell causes thermal runaway, thereby preventing the spread of heat.

[0034] Figure 2 As shown in FIG. 4, the thickness of the high-temperature-resistant sheet 3 is e. At the position where the anti-explosion sheet 2 is not provided with the notch 2-1, the distance between the edge of the high-temperature-resistant sheet 3 and the inner wall of the anti-explosion hole 1-1 is L. By setting L≥e / tan a, when the battery cell causes thermal runaway and the anti-explosion sheet 2 is folded, as shown in FIG. 5, it is ensured that the anti-explosion sheet 2 can be folded to an angle of a without being affected by the high-temperature-resistant sheet 3, thereby ensuring the pressure relief effect of the battery cell and improving the safety performance.

[0035] As shown in FIG. 6, the cover plate assembly is simple in structure and convenient to manufacture, which can prevent the spread of heat while ensuring that the explosion-proof valve can be normally opened to improve the safety of the battery. Figure 2 Figure 3 In some embodiments, the thickness of the high-temperature-resistant sheet 3 is less than the depth of the anti-explosion hole 1-1, and a protective sheet 4 is arranged at the end of the anti-explosion hole 1-1 away from the anti-explosion sheet 2.

[0036] As shown in FIG. 7, the thickness of the high-temperature-resistant sheet 3 is less than the depth of the anti-explosion hole 1-1, so that the high-temperature-resistant sheet 3 does not protrude from the anti-explosion hole 1-1. The protective sheet 4 is arranged at the top of the anti-explosion hole 1-1 to prevent the anti-explosion sheet 2 and the high-temperature-resistant sheet 3 from being touched by mistake.

[0037] In some embodiments, 0°≤a≤30°, 0.2mm≤L≤5mm and / or 0.1mm≤e≤2mm.

[0038] In some embodiments, 0°≤a≤30°, 0.2mm≤L≤5mm and / or 0.1mm≤e≤2mm. Figure 2 In some embodiments, 0°≤a≤30°, 0.2mm≤L≤5mm and / or 0.1mm≤e≤2mm.

[0039] In some embodiments, 0°≤a≤30°, 0.2mm≤L≤5mm and / or 0.1mm≤e≤2mm.

[0040] ​​Alpha is for example 0°, 2°, 5°, 10°, 15°, 20° or 30°, etc., and is not specifically limited. To avoid too large alpha angle, the gas in the battery cell cannot be quickly discharged, which is easy to cause safety accidents. Preferably, 0°≤ alpha ≤5°, to ensure that the battery cell is quickly depressurized when thermal runaway occurs.

[0041] As shown in Figure 4 , it is a top view structural schematic diagram of the explosion-proof hole 1-1. The length of the explosion-proof hole 1-1 is A, and the width is D. The length of the high-temperature-resistant sheet 3 is B, and the width is C. The edge of the high-temperature-resistant sheet 3 is arranged at equal intervals with the inner wall of the explosion-proof hole 1-1, that is, B = A + 2L, and D = C + 2L.

[0042] L is for example 0.2mm, 0.5mm, 1mm, 2mm, 3mm, 4mm or 5mm, etc., and is not specifically limited. On the one hand, to avoid too large L size, the coverage area of the high-temperature-resistant sheet 3 is small, which makes the exposed area of the explosion-proof sheet 2 too large, and still has the risk of being melted by the adjacent thermal runaway battery cell. On the other hand, to avoid too small L size, which is too close to the explosion-proof hole 1-1, which will hinder the combination of the explosion-proof sheet 2 and the high-temperature-resistant sheet 3. Preferably, 0.5mm≤L≤2mm, to ensure the flame-retardant effect of the explosion-proof sheet 2 and reduce the installation difficulty of the high-temperature-resistant sheet 3.

[0043] E is for example 0.1mm, 0.3mm, 0.5mm, 1mm, 1.5mm or 2mm, etc., and is not specifically limited. On the one hand, to avoid too large e size, which makes the explosion-proof sheet 2 cannot be normally opened, causing safety accidents. On the other hand, to avoid too small e size, which makes the high-temperature-resistant sheet 3 is easily burned through, which is not enough to protect the explosion-proof sheet 2, and still has the risk of being melted by the adjacent thermal runaway battery cell. Preferably, 0.3mm≤e≤1mm, to ensure that the explosion-proof sheet 2 can be normally opened, and at the same time prevent the spread of heat.

[0044] In some embodiments, a glue layer 5 is arranged between the high-temperature-resistant sheet 3 and the explosion-proof sheet 2. The orthographic projection of the high-temperature-resistant sheet 3 on the explosion-proof sheet 2 covers the orthographic projection of the glue layer 5 on the explosion-proof sheet 2.

[0045] A glue layer 5 is arranged between the high-temperature-resistant sheet 3 and the explosion-proof sheet 2 to achieve bonding. The glue layer 5 can be a one-piece structure or a segmented structure, and is not specifically limited.

[0046] As shown in Figure 5 , it is a structural schematic diagram of the high-temperature-resistant sheet 3 and the glue layer 5. The orthographic projection of the high-temperature-resistant sheet 3 on the explosion-proof sheet 2 covers the orthographic projection of the glue layer 5 on the explosion-proof sheet 2, that is, the size of the glue layer 5 is less than or equal to the size of the high-temperature-resistant sheet 3, to ensure that the high-temperature-resistant sheet 3 and the explosion-proof sheet 2 can be closely combined, and to avoid too large size of the glue layer 5, which covers the notch 2-1, affects the melting of the explosion-proof sheet 2, and makes the explosion-proof sheet 2 cannot be normally opened.

[0047] In some embodiments, the distance between the edge of the glue layer 5 and the edge of the high-temperature-resistant sheet 3 is n, 1 mm≤n≤10 mm; and / or the thickness of the glue layer 5 is m, 0.03 mm≤m≤0.4 mm.

[0048] As shown in FIG. 1, the length of the glue layer 5 is a, and the width of the glue layer 5 is c. The edge of the glue layer 5 is arranged at the same distance from the edge of the high-temperature-resistant sheet 3, that is, A=a+2n, and C=c+2n. Figure 5

[0049] For example, n is 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm, etc., and the specific value is not limited. On the one hand, n is not too large to make the high-temperature-resistant sheet 3 and the explosion-proof sheet 2 unstable, which may cause the high-temperature-resistant sheet 3 to separate from the explosion-proof sheet 2 and fail to prevent the spread of heat. On the other hand, n is not too small to make the glue layer 5 cover the score 2-1, which may affect the melting of the explosion-proof sheet 2 and make the explosion-proof sheet 2 fail to open normally. Preferably, 3 mm≤n≤6 mm to ensure that the high-temperature-resistant sheet 3 and the explosion-proof sheet 2 can be closely attached without affecting the normal opening of the explosion-proof sheet 2.

[0050] For example, m is 0.03 mm, 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.3 mm, or 0.4 mm, etc., and the specific value is not limited. On the one hand, m is not too large to make the glue solution flow uncontrollably during the process of bonding the high-temperature-resistant sheet 3 with the glue layer 5, which may make the high-temperature-resistant sheet 3 too high and hinder the normal opening of the explosion-proof sheet 2. On the other hand, m is not too small to make the bonding strength insufficient, which may make the high-temperature-resistant sheet 3 slide and fail to prevent the spread of heat. Preferably, 0.05 mm≤m≤0.15 mm to ensure that the high-temperature-resistant sheet 3 and the explosion-proof sheet 2 can be stably attached and the explosion-proof sheet 2 can open normally.

[0051] In some embodiments, the explosion-proof sheet 2 is provided with a reinforcing rib, and the glue layer 5 is provided with a corresponding avoiding hole 5-1.

[0052] The reinforcing rib can be arranged on the explosion-proof sheet 2 to improve the strength, as shown in FIG. 2, which is a structural schematic diagram of the high-temperature-resistant sheet 3 and the glue layer 5. The glue layer 5 can be provided with the avoiding hole 5-1 corresponding to the reinforcing rib to ensure that the glue layer 5 is flat, does not increase the height of the high-temperature-resistant sheet 3, and does not affect the normal opening of the explosion-proof sheet 2. Figure 6

[0053] In addition, because the explosion-proof sheet 2 may be inflated in the middle when it is installed into the explosion-proof hole 1-1, the avoiding hole 5-1 can also provide space for the inflation to ensure that the glue layer 5 is flat, does not increase the height of the high-temperature-resistant sheet 3, and does not affect the normal opening of the explosion-proof sheet 2.

[0054] In some embodiments, as shown in FIG. 3, the explosion-proof sheet 2 is provided with a reinforcing rib 2-2, and the glue layer 5 is provided with a corresponding avoiding hole 5-1. Figure 1 ​​As shown, the cover plate assembly includes pole posts 9, for example including positive pole posts and negative pole posts, which pass through the cover plate body 1, one end of the pole posts 9 is located below the cover plate body 1, for electrical connection with the electrode assembly in the battery cell shell; the other end of the pole posts 9 is located above the cover plate body 1, for electrical connection with the external circuit of the battery cell.

[0055] The pole posts 9 can be sleeved with sealing rings 10, for example rubber rings, which can improve the insulation between the pole posts 9 and the cover plate body 1. The lower end of the pole posts 9 is connected with a connecting pin 11, for connecting the pole tabs of the electrode assembly.

[0056] In some embodiments, as shown, Figure 1 As shown, the top of the cover plate body 1 is provided with an upper insulating member 6, and the bottom is provided with a lower insulating member 7, which are for example plastic members, to ensure the insulation between the cover plate body 1 and the pole posts 9. The cover plate body 1 can also be provided with a limiting groove to accommodate the upper insulating member 6. The top surface of the upper insulating member 6 is provided with a riveting member 8, the pole posts 9 pass through the lower insulating member 7, the cover plate body 1 and the upper insulating member 6 in turn, and are riveted with the riveting member 8. The riveting member 8 is for example a conductive block, which can be electrically connected with the external circuit. The upper insulating member 6 is located between the riveting member 8 and the cover plate body 1, which can ensure the insulation between the riveting member 8 and the cover plate body 1. The cover plate body 1 is also provided with a liquid injection hole 1-2 which passes through the cover plate body 1, for injecting electrolyte into the battery cell.

[0057] In some embodiments of the present application, a battery cell is provided, which includes a shell, the shell is connected with the cover plate assembly as described in any of the above embodiments, and is internally provided with an electrode assembly.

[0058] The shell is for example an aluminum shell, which can be welded with the cover plate assembly. The battery cell has a simple structure, is easy to manufacture, and has high safety.

[0059] In some embodiments of the present application, a secondary battery is provided, which includes the battery cell as described in any of the above embodiments.

[0060] The secondary battery is for example a battery module, a battery pack, etc., which includes a housing, and the housing is internally provided with a plurality of battery cells. The secondary battery can be applied to an electrical equipment, which can be a vehicle, a mobile phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy and an electric tool, etc. The vehicle can be a fuel automobile, a gas automobile or a new energy automobile, and the new energy automobile can be a pure electric automobile, a hybrid electric automobile or a range extended automobile, etc.; the spacecraft includes an airplane, a rocket, a space shuttle and a spacecraft, etc.; the electric toy includes a fixed or mobile electric toy, for example a game console, an electric automobile toy, an electric ship toy and an electric airplane toy, etc.; the electric tool includes a metal cutting electric tool, a grinding electric tool, an assembling electric tool and a railway electric tool, for example an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact electric drill, a concrete vibrator and an electric planer, etc.

[0061] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present application (including the claims) is limited to these examples. Within the scope of the present application, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the embodiments of the present application as described above, which are not provided in detail for the sake of simplicity.

[0062] In addition, when details are set forth to describe exemplary embodiments of the present application, it will be apparent to those skilled in the art that the present application embodiments can be implemented without these details or with variations in these details. Therefore, these descriptions should be considered illustrative rather than restrictive.

[0063] While the present application has been described in conjunction with the embodiments thereof, many alternatives, modifications and variations of these embodiments will be apparent to those skilled in the art in light of the foregoing description.

[0064] The embodiments of the present application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present application should be included in the scope of protection of this application.

Claims

1. A cover plate assembly for enclosing a battery cell, characterized by, The cover plate body is provided with an explosion-proof hole. An explosion-proof sheet is installed at one end of the explosion-proof hole close to the inside of the battery cell. When the pressure in the battery cell reaches a threshold value, the explosion-proof sheet is folded along one edge to open. The included angle between the folded explosion-proof sheet and the inner wall of the explosion-proof hole is α. A high-temperature-resistant sheet is arranged on the surface of the explosion-proof sheet away from the inside of the battery cell. The thickness of the high-temperature-resistant sheet is e. Before the explosion-proof sheet is folded, the distance between the edge of the high-temperature-resistant sheet and the inner wall of the explosion-proof hole is L, and L≥e / tanα. The thickness of the high-temperature-resistant sheet is less than the depth of the explosion-proof hole. A protective sheet is installed at the end of the explosion-proof hole away from the explosion-proof sheet.

2. The cover plate assembly of claim 1, wherein, 0°≤α≤30°, 0.2mm≤L≤5mm and / or 0.1mm≤e≤2mm.

3. The cover plate assembly of claim 1, wherein, 0°≤α≤5°, 0.5mm≤L≤2mm, 0.3mm≤e≤1mm.

4. The cover plate assembly of claim 3, wherein, A glue layer is arranged between the high-temperature-resistant sheet and the explosion-proof sheet. The orthographic projection of the high-temperature-resistant sheet on the explosion-proof sheet covers the orthographic projection of the glue layer on the explosion-proof sheet.

5. The cover plate assembly of claim 1, wherein, The distance between the edge of the glue layer and the edge of the high-temperature-resistant sheet is n, and 1mm≤n≤10mm. The thickness of the glue layer is m, and 0.03mm≤m≤0.4mm.

6. The cover plate assembly of claim 5, wherein, 3mm≤n≤6mm, 0.05mm≤m≤0.15mm.

7. The cover plate assembly of claim 6, wherein, A reinforcing rib is arranged on the explosion-proof sheet, and an avoiding hole corresponding to the reinforcing rib is arranged on the glue layer.

8. The cover plate assembly of claim 5, wherein, The shell is connected with the cover plate assembly as claimed in any one of claims 1-8, and is internally provided with an electrode assembly.

9. An electric cell characterized by The battery cell comprises the electrode assembly as claimed in claim 9.

10. A secondary battery characterized by comprising: ​

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