Battery cover assembly capable of improving safety and high power performance and battery

Abstract

The invention discloses a battery cover assembly capable of improving safety and high power performance and a battery, and belongs to the technical field of batteries, the battery cover assembly comprises a battery cover plate, a positive pole, a negative pole, an anti-explosion valve and a liquid injection hole cover, the positive pole comprises a positive current collector, a positive leading-out end, a positive sealing piece, a positive external insulating piece and a positive internal insulating piece, the cathode column comprises a cathode current collector, a cathode leading-out end, a cathode sealing piece, a cathode external insulating piece and a cathode internal insulating piece; and the battery cover plate, and the anode internal insulating piece and the cathode internal insulating piece which are positioned below the left side and the right side of the battery cover plate define a cavity with the height of not less than 3mm. According to the invention, the gas circulation channel is reserved in the battery, and meanwhile, the obstruction of structural members in the battery on gas flow is reduced, so that gas can quickly reach the anti-explosion valve port, and the safety of the battery is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of batteries, and in particular relates to a battery cover assembly and a battery with improved safety and high power performance. Background Art

[0002] In recent years, with the development of pure electric vehicles, hybrid vehicles, etc. in the civilian field and the development of various high-power equipment in the military field, the requirements for high-power discharge capabilities of batteries have become increasingly higher.

[0003] To ensure the safety of the battery during use, one of the methods commonly used in the current known technology is to set an explosion-proof valve on the battery cover. When the internal pressure of the battery rises to a certain level, the explosion-proof valve opens and the internal gas is released to the outside of the shell, thereby avoiding battery explosion.

[0004] In conventional battery design, in order to improve the volumetric energy of the battery, it is often hoped that as much battery active material as possible can be loaded into the limited internal space of the battery, and the internal space utilization rate of the battery is very high. When this design concept is transplanted into the design of high-power batteries, it will bring serious safety hazards.

[0005] For high-power batteries, especially ultra-high-power batteries with a discharge capacity of more than 30C, many measures are often used in the design to reduce the internal resistance of the battery, such as using high specific surface area and small particle size materials for the positive and negative active materials of the battery, adding more conductive agents to the electrodes, optimizing the conductive network of the conductive agents, and increasing the conductive cross-sectional area of ​​the current collector. Since the internal resistance of this type of battery is very small, the internal short-circuit current of the battery is very large, the internal reaction is very violent, and the gas generation rate is much higher than that of ordinary high-energy-density batteries in the event of internal short circuit, external short circuit, acupuncture, extrusion, etc. In this case, if the battery is overfilled, the channel for gas flow will be narrow, which will seriously hinder the release of gas inside the battery. In extreme cases, the gas release rate will be lower than the generation rate, and the gas will cause an explosion when it accumulates inside the battery to the pressure limit of the shell.

[0006] During battery use, when the internal pressure rises to the explosion-proof valve opening pressure, the explosion-proof valve opens and the gas inside the battery is discharged from the explosion-proof valve to prevent the gas inside the battery from accumulating pressure and preventing the battery from exploding. In the face of puncture, extrusion, short circuit and other situations, the gas inside the battery is generated very quickly. If the gas flow channel inside the battery is narrow, it will greatly affect the speed at which the gas reaches the explosion-proof valve port, causing the gas inside the battery to accumulate. Therefore, it is necessary to design a battery structure with an unobstructed gas discharge channel for high-power batteries. Summary of the invention

[0007] In view of the problems existing in the prior art, the present invention provides a battery cover assembly and a battery with improved safety and high power performance, and has a smooth air discharge channel.

[0008] The present invention is implemented as follows: a battery cover assembly with improved safety and high-power performance includes a battery cover, a positive electrode column, a negative electrode column, an explosion-proof valve and a liquid injection hole cover, the positive electrode column includes a positive electrode collector, a positive electrode lead-out terminal, a positive electrode seal, a positive electrode external insulating member, and a positive electrode internal insulating member, the negative electrode column includes a negative electrode collector, a negative electrode lead-out terminal, a negative electrode seal, a negative electrode external insulating member, and a negative electrode internal insulating member, the battery cover and the positive electrode internal insulating member and the negative electrode internal insulating member located below the left and right sides of the battery cover form a cavity with a height of not less than 3 mm.

[0009] The positive electrode internal insulating part and the negative electrode internal insulating part adopt a split structure.

[0010] The positive electrode internal insulating member and the negative electrode internal insulating member adopt an integrated structure to form an integrated internal insulating member.

[0011] The difference between the thickness of the thicker one of the positive and negative internal insulating parts in the integrated internal insulating part and the thickness of the connecting part of the positive and negative internal insulating parts is not less than 3 mm.

[0012] At least one of the positive electrode lead-out terminal and the negative electrode lead-out terminal is fastened and assembled with the battery cover plate by metal riveting.

[0013] A gasket is arranged around the lead-out terminal, and the highest point of the gasket is located lower than the highest point of the lead-out terminal. Pressure is applied to the upper surface of the lead-out terminal in a direction perpendicular to the upper surface of the lead-out terminal to deform the lead-out terminal. The deformation of the lead-out terminal allows the lead-out terminal and the gasket to be tightly fixed, and at the same time, the lead-out terminal and the battery cover are tightly fixed.

[0014] A protrusion is arranged on the side wall of the positive lead-out terminal or the negative lead-out terminal, and at least one of the positive external insulating part and the negative external insulating part is firmly connected with the positive lead-out terminal or the negative lead-out terminal by injection molding, and is firmly connected with the battery cover.

[0015] At least one of the positive electrode lead-out terminal and the negative electrode lead-out terminal and its corresponding current collector are connected by welding; at least one of the positive electrode lead-out terminal and the negative electrode lead-out terminal and its corresponding current collector adopt an integrated structure; the positive electrode current collector and the negative electrode current collector adopt a pin method; at least one of the positive electrode lead-out terminal and the negative electrode lead-out terminal is provided with at least one threaded hole on its upper surface.

[0016] A battery using the above-mentioned battery cover assembly with improved safety and high-power performance includes a battery shell and a plate group, wherein the plate group is alternately stacked in the order of a diaphragm, a positive electrode, a diaphragm, and a negative electrode, the negative electrode is arranged on the outside, and the diaphragm is wrapped on the outermost side, or a winding structure is adopted; the positive electrode and the negative electrode each have a tab, which is led out from both sides of the plate group in the form of a positive electrode tab bundle and a negative electrode tab bundle, and is welded to the corresponding current collector.

[0017] The outside of the electrode group is wrapped with an insulating film, and the insulating film is provided with insulating film openings, two of which lead out the positive pole ear bundle and the negative pole ear bundle of the electrode group respectively, and the other opening is facing the explosion-proof valve of the battery cover; the total thickness of the electrode group is 85% to 95% of the width of the inner cavity of the battery shell.

[0018] The advantages and technical effects of the present invention are as follows: the present invention reserves a gas flow channel inside the battery and reduces the obstruction of the internal structural parts of the battery to the gas flow, so that the gas can quickly reach the explosion-proof valve port, thereby improving the safety of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of a preferred embodiment 1 of the present invention;

[0020] Figure 2 It is a schematic diagram of the structure of the integrated positive electrode internal insulating member and the negative electrode internal insulating member in the preferred embodiment 1 of the present invention;

[0021] Figure 3 It is a cross-sectional schematic diagram of a preferred embodiment 1 of the present invention;

[0022] Figure 4 This is a schematic diagram of the parts before assembly of the preferred embodiment 1 of the present invention;

[0023] Figure 5 Schematic diagram of coating of the positive electrode sheet of the present invention;

[0024] Figure 6 Schematic diagram of coating of the negative electrode sheet of the present invention;

[0025] Figure 7 is a schematic diagram of the electrode assembly of the present invention;

[0026] Figure 8 is a three-dimensional schematic diagram of the electrode assembly of the present invention;

[0027] Fig. 9 It is a cross-sectional view of the battery case of the present invention.

[0028] In the figure: 1. battery cover; 2. positive electrode current collector; 3. positive electrode lead-out terminal; 4. positive electrode external insulating member; 5. positive electrode internal insulating member; 6. negative electrode internal insulating member; 7. negative electrode current collector; 8. negative electrode lead-out terminal; 9. negative electrode external insulating member; 10. explosion-proof valve; 11. injection hole cover; 12. local riveting point; 13. threaded hole; 14. gasket; 15. connecting part of positive and negative electrode internal insulating members; 16. positive electrode seal; 17. negative electrode seal; 18. injection hole seal; 19. plate group; 20. battery shell; 21. positive electrode tab bundle; 22. negative electrode tab bundle; 23. insulating film; 24. positive electrode; 25. diaphragm; 26. negative electrode; 27. positive electrode tab; 28. negative electrode tab. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0030] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0031] In addition, the terms "first", "second", etc. are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features.

[0032] Thus, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0033] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0034] The electrical devices, controllers, etc. described in the present invention are all conventionally configured, and the electrical connection method is also conventionally connected.

[0035] like Figure 1-4 As shown, the battery cover assembly for improving safety and high power performance of the present invention comprises a battery cover plate 1, a positive electrode column, a negative electrode column, an explosion-proof valve 10 and a liquid injection hole cover 11, the positive electrode column comprises a positive electrode collector 2, a positive electrode lead-out terminal 3, a positive electrode seal 16, a positive electrode external insulating member 4, and a positive electrode internal insulating member 5, the negative electrode column comprises a negative electrode collector 7, a negative electrode lead-out terminal 8, a negative electrode seal 17, a negative electrode external insulating member 9, and a negative electrode internal insulating member 6, the battery cover plate 1 and the positive electrode internal insulating member 5 and the negative electrode internal insulating member 6 located below the left and right sides of the battery cover plate 1 form a cavity with a height of not less than 3 mm.

[0036] The positive electrode internal insulating member 5 and the negative electrode internal insulating member 6 adopt a separate structure. Or the positive electrode internal insulating member 5 and the negative electrode internal insulating member 6 adopt an integrated structure to form an integrated internal insulating member. The difference between the thickness of the thicker of the positive and negative electrode internal insulating members in the integrated internal insulating member and the thickness of the connecting portion of the positive and negative electrode internal insulating members is not less than 3 mm.

[0037] At least one of the positive electrode lead-out terminal 3 and the negative electrode lead-out terminal 8 is fastened and assembled with the battery cover plate 1 by metal riveting.

[0038] A gasket 14 is arranged around the lead-out terminal, and the highest point of the gasket 14 is located lower than the highest point of the lead-out terminal. Pressure is applied to the upper surface of the lead-out terminal in a direction perpendicular to the upper surface of the lead-out terminal to deform the lead-out terminal. The deformation of the lead-out terminal allows the lead-out terminal and the gasket to be tightly fixed, and at the same time, the lead-out terminal and the battery cover are tightly fixed.

[0039] A protrusion is provided on the side wall of the positive lead-out terminal 3 or the negative lead-out terminal 8, and at least one of the positive external insulating member 4 and the negative external insulating member 9 is firmly connected with the positive lead-out terminal 3 or the negative lead-out terminal 8 by injection molding, and is firmly connected with the battery cover plate 1.

[0040] At least one of the positive electrode lead-out terminal 3 and the negative electrode lead-out terminal 8 and its corresponding current collector are connected by welding; at least one of the positive electrode lead-out terminal 3 and the negative electrode lead-out terminal 8 and its corresponding current collector adopts an integrated structure; the positive electrode current collector 2 and the negative electrode current collector 7 adopt a pin method; at least one of the positive electrode lead-out terminal 3 and the negative electrode lead-out terminal 8 has at least one threaded hole 13 provided on its upper surface.

[0041] like Fig. 9As shown, the present invention adopts the battery of the battery cover assembly with improved safety and high power performance, including a battery shell and a plate group 19, wherein the plate group 19 is alternately stacked in the order of a separator 25, a positive electrode 24, a separator 25, and a negative electrode 26, and the negative electrode 26 is arranged on the outside, and the separator is wrapped on the outermost side, or a winding structure is adopted; the positive electrode and the negative electrode each contain a pole ear, which is led out from both sides of the pole plate group 19 in the form of a positive pole ear bundle 21 and a negative pole ear bundle 22, and is welded to the corresponding current collector.

[0042] like Figure 8 As shown, the outside of the electrode group 19 is wrapped with an insulating film 23, and the insulating film 23 is provided with insulating film openings, two of which lead out the positive pole tab bundle 21 and the negative pole tab bundle 22 of the electrode group respectively, and the other opening is facing the explosion-proof valve 10 of the battery cover; the total thickness of the electrode group 19 is 85% to 95% of the width of the inner cavity of the battery shell.

[0043] The present invention applies pressure only to the periphery of the upper surface, which is achieved by applying pressure only to local riveting points on the periphery, and the number of the riveting points is not less than 2.

[0044] In order to further understand the content, features and effects of the present invention, the following embodiments are given as examples and described in detail with reference to the accompanying drawings:

[0045] Example 1

[0046] A battery cover assembly includes: 1. a battery cover; 2. a positive electrode current collector; 3. a positive electrode lead-out terminal; 4. a positive electrode external insulating member; 5. a positive electrode internal insulating member; 6. a negative electrode internal insulating member; 7. a negative electrode current collector; 8. a negative electrode lead-out terminal; 9. a negative electrode external insulating member; 10. an explosion-proof valve; 11. a liquid injection hole cover; 12. local riveting points; 13. threaded holes; 14. a gasket; 15. a connecting portion of the positive and negative electrode internal insulating members; 16. a positive electrode seal; 17. a negative electrode seal; and 18. a liquid injection hole seal.

[0047] The thickness of the positive electrode internal insulation and the negative electrode internal insulation is 5.3mm, and an integrated structure is adopted. The thickness of the connection between the two parts is 2mm, and the difference is 3.3mm, which reserves a channel for the internal gas of the battery to flow to the explosion-proof valve. The positive electrode current collector and the positive electrode lead-out terminal adopt an integrated structure. The negative electrode lead-out terminal and the negative electrode current collector are welded together by laser welding. Two M6 threaded holes are set on each of the positive and negative electrode lead-out terminals.

[0048] The positive lead passes through the positive seal, positive internal insulation, battery cover, positive external insulation, and gasket in turn, and then rivets to make each part fit tightly. When riveting, the mold is first used to evenly apply downward pressure around the gasket to deform the positive seal below. Then, the mold is used to apply downward pressure at the local riveting points shown in the figure to deform the positive lead and tightly fit with the gasket, while keeping the positive seal in a compressed deformation state to achieve permanent sealing. The negative lead is riveted in the same way.

[0049] Example 2

[0050] A high-power and high-safety battery, wherein the battery cover adopts the battery cover in the above-mentioned embodiment 1, and the electrochemical system of the battery adopts a lithium iron phosphate-graphite system.

[0051] Lithium iron phosphate, conductive carbon black, carbon nanotubes, PVDF binder slurry, etc. were mixed evenly in a certain proportion to prepare positive electrode slurry, and the positive electrode slurry was evenly coated on both sides of the aluminum foil. A non-coating area with a width of 11 mm was reserved during coating. The positive electrode sheet was prepared by drying, rolling, and punching. The thickness was 100 μm, and the total amount of double-sided coating was 20 mg / cm 2 The thickness of the aluminum foil is 15 μm, the length of the pole piece excluding the pole ear is 119 mm, and the width is 80 mm. The pole ear is 7 mm long, 11 mm wide, and is centered. Figure 5 As shown, area A is the positive electrode non-coating area; area B is the positive electrode coating area.

[0052] Graphite, conductive carbon black, SBR binder slurry, etc. were mixed evenly in a certain proportion to prepare the negative electrode slurry, and the negative electrode slurry was evenly coated on both sides of the copper foil. A non-coating area with a width of 9 mm was reserved during coating. The negative electrode sheet was prepared by drying, rolling, and punching. The thickness was 100 μm, and the total amount of double-sided coating was 10 mg / cm 2 The thickness of the aluminum foil is 10 μm, the length of the pole piece excluding the pole ear is 123 mm, and the width is 84 mm. The pole ear is 60 mm long, 9 mm wide, and is centered. Figure 6 As shown, area C is the negative electrode non-coated area; area D is the negative electrode coated area.

[0053] like Figure 7As shown: the electrode group 19 is prepared by stacking the separator 25, the positive electrode sheet 24, the separator 25, the negative electrode sheet 26, the separator 25, the positive electrode sheet 24, the separator 25, the negative electrode sheet 26... in the order of lamination, and the positive and negative electrode non-coating areas are located at both ends of the electrode group as the positive and negative electrode ears. All the positive ears form a positive electrode ear bundle, and all the negative ears form a negative electrode ear bundle. The thickness of a single-layer separator is about 20μm. The total thickness of the electrode group is about 24mm. An insulating film 23 is wrapped around the periphery of the electrode group, and the positive electrode ear bundle and the negative electrode ear bundle extend from the openings at both ends of the insulating film. Another opening is left in the middle of the side of the insulating film. The position of the opening is such that after the battery shell cover is assembled, the opening is opposite to the explosion-proof valve on the battery cover.

[0054] All positive electrode tabs are divided into two upper and lower bundles to form two positive electrode tab bundles 21. All negative electrode tabs are divided into two upper and lower bundles to form two negative electrode tab bundles 22. Figure 8 shown.

[0055] The positive electrode tab bundle and the positive electrode current collector 2 are welded together by laser, and the negative electrode tab bundle and the negative electrode current collector 7 are welded together by laser.

[0056] The battery case 20 has an external dimension of 148 mm×27 mm×97 mm, a thickness of 0.6 mm, is made of aluminum alloy, and has an inner cavity width of 25.8 mm.

[0057] The electrode plate group with the battery cover welded to it is placed into the battery shell, and the battery shell and the battery cover are welded together using a laser.

[0058] The electrolyte is injected into the battery through the injection hole. The amount of electrolyte is 130g. The injection hole seal is placed in the injection hole, and the injection hole cover is placed on it and laser welded to the battery cover. Figure 3 , Fig. 9 The main components are shown in cross-section, and the battery case is shown in cutaway form.

[0059] The battery is formed to complete the preparation of the battery. The battery capacity is 20Ah and has the ability to continuously discharge at a current of more than 30C.

[0060] In this embodiment, the battery cover, positive electrode internal insulation, and negative electrode internal insulation enclose a cavity with a width of 3.3 mm. The thickness of the electrode group is 24 mm, the width of the battery shell cavity is 25.8 mm, and the total thickness of the electrode group is 93% of the width of the battery shell cavity.

[0061] When a battery is punctured or other safety incident occurs, a large amount of gas generated inside the battery plate group can smoothly reach the explosion-proof valve port through the three openings of the insulating film: In the first channel, the gas generated by the plate group directly reaches the explosion-proof valve port through the side openings of the insulating film of the plate group. In the second channel, the gas generated by the plate group flows through the openings of the insulating film where the positive electrode lug bundle is located to the gap between the plate group and the battery shell, and flows to the explosion-proof valve port through the cavity surrounded by the battery cover, the positive electrode internal insulating parts, and the negative electrode internal insulating parts.

[0062] When a needle puncture test was conducted on a fully charged battery, the battery's explosion-proof valve opened and released a large amount of white smoke, but the battery did not explode or catch fire, and had very good safety.

[0063] This design is more beneficial to improving safety for high-power batteries because the internal resistance of high-power batteries is very small, and the gas generated inside will be faster when situations such as needle puncture occur.

[0064] Therefore, the present invention is very suitable for use in high-power and high-safety batteries.

[0065] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A battery cover assembly with improved safety and high power performance, comprising a battery cover plate (1), a positive electrode column, a negative electrode column, an explosion-proof valve (10) and a liquid injection hole cover (11), wherein the positive electrode column comprises a positive electrode current collector (2), a positive electrode lead-out terminal (3), a positive electrode seal (16), a positive electrode external insulating member (4), and a positive electrode internal insulating member (5), and the negative electrode column comprises a negative electrode current collector (7), a negative electrode lead-out terminal (8), a negative electrode seal (17), a negative electrode external insulating member (9), and a negative electrode internal insulating member (6), characterized in that: The battery cover plate (1) and the positive electrode internal insulating member (5) and the negative electrode internal insulating member (6) located below the left and right sides of the battery cover plate (1) form a cavity with a height of not less than 3 mm.

2. The battery cover assembly with improved safety and high power performance according to claim 1, characterized in that: The positive electrode internal insulating component (5) and the negative electrode internal insulating component (6) adopt a split structure.

3. The battery cover assembly with improved safety and high power performance according to claim 1, characterized in that: The positive electrode internal insulating member (5) and the negative electrode internal insulating member (6) adopt an integrated structure to form an integrated internal insulating member.

4. The battery cover assembly with improved safety and high power performance according to claim 3, characterized in that: The difference between the thickness of the thicker one of the positive and negative internal insulating parts in the integrated internal insulating part and the thickness of the connecting part of the positive and negative internal insulating parts is not less than 3 mm.

5. The battery cover assembly with improved safety and high power performance according to claim 1, characterized in that: At least one of the positive electrode lead-out terminal (3) and the negative electrode lead-out terminal (8) is fastened and assembled with the battery cover plate (1) by means of metal riveting.

6. The battery cover assembly with improved safety and high power performance according to claim 5, characterized in that: A gasket (14) is arranged around the lead-out terminal, and the highest point of the gasket (14) is located lower than the highest point of the lead-out terminal. Pressure is applied to the upper surface of the lead-out terminal in a direction perpendicular to the upper surface of the lead-out terminal to deform the lead-out terminal. The lead-out terminal and the gasket are tightly fixed through the deformation of the lead-out terminal, and the lead-out terminal and the battery cover are tightly fixed at the same time.

7. The battery cover assembly with improved safety and high power performance according to claim 1, characterized in that: A protrusion is provided on the side wall of the positive electrode lead-out terminal (3) or the negative electrode lead-out terminal (8), and at least one of the positive electrode external insulating member (4) and the negative electrode external insulating member (9) is firmly connected to the positive electrode lead-out terminal (3) or the negative electrode lead-out terminal (8) by injection molding, and is firmly connected to the battery cover plate (1).

8. The battery cover assembly with improved safety and high power performance according to claim 5, characterized in that: At least one of the positive electrode lead-out terminal (3) and the negative electrode lead-out terminal (8) and the current collector corresponding thereto are connected by welding; at least one of the positive electrode lead-out terminal (3) and the negative electrode lead-out terminal (8) and the current collector corresponding thereto adopts an integrated structure; the positive electrode current collector (2) and the negative electrode current collector (7) adopt a pin-type method; and at least one of the positive electrode lead-out terminal (3) and the negative electrode lead-out terminal (8) is provided with at least one threaded hole (13) on its upper surface.

9. A battery using the battery cover assembly with improved safety and high power performance as claimed in any one of claims 1 to 8, characterized in that: The invention comprises a battery shell and an electrode group (19), wherein the electrode group (19) is alternately stacked in the order of a separator (25), a positive electrode (24), a separator (25), and a negative electrode (26), wherein the negative electrode (26) is arranged on the outside and the separator is wrapped on the outermost side, or a winding structure is adopted; the positive electrode and the negative electrode each have a pole ear, which is led out from both sides of the electrode group (19) in the form of a positive pole ear bundle (21) and a negative pole ear bundle (22), and is welded to the corresponding current collector.

10. The battery using the battery cover assembly with improved safety and high power performance according to claim 9, characterized in that: The electrode group (19) is wrapped with an insulating film (23) on the outside, and the insulating film (23) is provided with insulating film openings, wherein two openings lead out the positive electrode tab bundle (21) and the negative electrode tab bundle (22) of the electrode group respectively, and the other opening is directed toward the explosion-proof valve (10) of the battery cover; the total thickness of the electrode group (19) is 85% to 95% of the width of the inner cavity of the battery shell.

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