A lithium ion secondary battery with high safety performance

Abstract

The application discloses a high-safety lithium ion secondary battery, which comprises a battery shell, an insulating protective tape wrapped on the outer surface of the battery shell, a pole group protection sleeve arranged in the battery shell, a pole group arranged in the pole group protection sleeve, a positive electrode lug and a negative electrode lug arranged on the top of the pole group, an upper support covering the top of the pole group, positive electrode passing holes and negative electrode passing holes arranged at the left and right ends of the upper support, a battery cover and an outer gasket arranged above the upper support from bottom to top, a positive electrode column and a negative electrode column arranged at the left and right ends of the battery cover, the positive electrode lug of the pole group being connected with the lower end of the positive electrode column after penetrating through the positive electrode passing hole upward, the negative electrode lug of the pole group being connected with the lower end of the negative electrode column after penetrating through the negative electrode passing hole upward, at least one outer side surface of the pole group protection sleeve being an frosted surface, and / or at least one inner side surface of the battery shell being an frosted surface. The application can effectively improve the safety performance of the battery when responding to external impacts such as falling, vibration and bumping, and improve the overall safety performance of the lithium ion battery.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery, in particular to a high-safety lithium ion secondary battery. BACKGROUND

[0002] Lithium ion battery has the advantages of high specific energy, high cycle life and long storage time, and is widely used not only in portable electronic devices (such as mobile phones, digital cameras and laptop computers), but also in electric vehicles, electric bicycles and electric tools.

[0003] The performance of the vehicle-mounted large-capacity power battery directly affects the overall performance of the electric vehicle. This puts higher requirements on the vehicle-mounted power battery of the electric vehicle (such as higher safety, larger specific capacity and lighter weight). Therefore, the safety performance of the lithium ion battery is increasingly required.

[0004] For lithium ion batteries, safety performance is an important indicator for measuring lithium ion batteries and is also an indicator that battery manufacturers and customers are concerned about. Therefore, it is of great significance to improve the safety performance of the battery during the design and manufacture of the battery.

[0005] At present, the existing lithium ion battery may cause internal short circuit, safety valve opening and electrolyte overflow when subjected to external impact such as vibration or drop, which causes serious safety hazards and seriously affects the safety of the battery during use.

[0006] Therefore, it is urgent to develop a technology that can reliably improve the safety of lithium ion batteries when responding to external impact. SUMMARY

[0007] The purpose of the present application is to provide a high-safety lithium ion secondary battery to overcome the technical defects of the prior art.

[0008] To this end, the present application provides a high-safety lithium ion secondary battery, which comprises an outer gasket, a battery cover, an upper support, a pole group, a pole group protection sleeve, a battery shell and an insulating protective tape.

[0009] The outer surface of the hollow battery shell with a top opening is wrapped with an insulating protective tape.

[0010] A hollow pole group protection sleeve with a top opening is arranged in the inner cavity of the battery shell.

[0011] The inner cavity of the pole group protection sleeve is provided with a pole group.

[0012] The top left and right ends of the pole group are respectively provided with a positive electrode lug and a negative electrode lug.

[0013] The top of the pole group is covered with an upper support;

[0014] The left and right ends of the upper support are respectively provided with positive and negative through holes;

[0015] The uppermost part of the upper support is sequentially provided with a battery cover and an outer gasket from bottom to top;

[0016] The left and right ends of the battery cover are respectively provided with positive and negative post mounting holes;

[0017] The horizontal middle position of the battery cover is provided with a safety valve;

[0018] The outer gasket is provided with a safety valve exposure hole at a position corresponding to the safety valve;

[0019] A positive post is vertically and completely arranged in the positive post mounting hole;

[0020] A negative post is vertically and completely arranged in the negative post mounting hole;

[0021] The positive pole ear of the pole group is connected to the lower end of the positive post after being vertically and completely arranged in the positive through hole of the upper support;

[0022] The negative pole ear of the pole group is connected to the lower end of the negative post after being vertically and completely arranged in the negative through hole of the upper support;

[0023] The top of the battery cover is provided with an outer gasket;

[0024] The left and right ends of the outer gasket are respectively provided with positive and negative post accommodating holes;

[0025] The upper end of the positive post is embedded in the positive post accommodating hole;

[0026] The upper end of the negative post is embedded in the negative post accommodating hole;

[0027] Among them, the plurality of outer sides of the pole group protective sleeve used to contact the inner side of the battery shell, at least one of the outer sides is a frosted surface;

[0028] And / or, for the plurality of inner sides of the battery shell, at least one of the inner sides is a frosted surface.

[0029] Preferably, the shape of the pole group protective sleeve and the battery shell is a rectangular parallelepiped.

[0030] Preferably, the shape of the insulating protective tape is a "N" shape;

[0031] The insulating protective tape is pasted on the front and back sides of the battery shell.

[0032] Preferably, the roughness of the matte surface of the polar group protection sleeve and the roughness of the matte surface of the battery shell are both 6.3 μm≤Ra≤100 μm, wherein Ra is the profile arithmetic mean deviation.

[0033] Preferably, when the outer side surface of the polar group protection sleeve and the inner side surface of the battery shell both have matte surfaces, the matte surface on the polar group protection sleeve and the matte surface on the battery shell are in positive correspondence and in contact with each other.

[0034] Preferably, the polar group protection sleeve is a protection sleeve made of PET, PP or PE.

[0035] The battery shell is a hard shell or a soft shell.

[0036] Preferably, the material surface of the polar group protection sleeve is clean and free of oil stains and the edges are free of burrs.

[0037] The polar group protection sleeve is a one-piece protection sleeve or a split protection sleeve.

[0038] Preferably, the bottom of the polar group protection sleeve is provided with a plurality of holes at equal intervals.

[0039] Preferably, the left and right outer side surfaces of the polar group protection sleeve are matte surfaces.

[0040] The matte area of the matte surface is located at the lower end of the left and right outer side surfaces of the polar group protection sleeve.

[0041] As can be seen from the technical solutions provided by the present application, compared with the prior art, the present application provides a lithium ion secondary battery with high safety performance, which is designed scientifically and can effectively improve the safety performance of the battery when responding to external impacts such as falling, vibration and bumping, thereby improving the overall safety performance of the lithium ion battery, promoting the batch production and application of the lithium ion battery, and being beneficial to improving the market application prospect of the products of the battery production enterprise, and having great production practical significance. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 A cross-sectional view of a lithium ion secondary battery with high safety performance provided by the present application;

[0043] Figure 2 A perspective structural diagram of a polar group protection sleeve in a lithium ion secondary battery with high safety performance provided by the present application;

[0044] Figure 3 A front structural diagram of a lithium ion secondary battery with high safety performance provided by the present application (the front structural diagram of the battery of the comparative example is the same), Figure 3 The A area in the above is the area of the battery of the example and the battery of the comparative example for X-Ray photography.

[0045] Figure 4A schematic diagram obtained by X-ray photographing of the battery of the embodiment of the present application after the inverted drop test;

[0046] Figure 5 A schematic diagram obtained by X-ray photographing of the battery of the comparative example after the inverted drop test;

[0047] In the figure, 1 is an outer gasket, 2 is a battery cover, 3 is an upper support, 4 is a pole group, 5 is a pole group protective sleeve, 6 is a battery shell, and 7 is an insulating protective tape;

[0048] 10 is a safety valve exposure hole, 50 is a hole, and 51 is a frosted area;

[0049] 21 is a positive pole, and 22 is a negative pole;

[0050] 31 is a positive pole passing hole, and 32 is a negative pole passing hole;

[0051] 41 is a positive pole lug, and 42 is a negative pole lug. DETAILED DESCRIPTION

[0052] The technical solutions of the present application will be described clearly and completely below in combination with the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0053] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", and the like are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second", and the like can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0054] In the description of the present application, it should be noted that unless specifically defined and limited, the terms "mounting", "connection", "linking" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium, or internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0055] The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0056] Referring to Figures 1 to 5 The present application provides a high safety performance lithium ion secondary battery, comprising an outer gasket 1, a battery cover 2, an upper support 3, a pole group 4, a pole group protection sleeve 5, a battery shell 6 and an insulating protective tape 7.

[0057] The outer surface of the hollow battery shell 6 with a top opening is wrapped with an insulating protective tape 7.

[0058] In the inner cavity of the battery shell 6, a hollow pole group protection sleeve 5 with a top opening is arranged.

[0059] In the inner cavity of the pole group protection sleeve 5, a pole group 4 is arranged.

[0060] The top left and right ends of the pole group 4 are respectively provided with a positive electrode lug 41 and a negative electrode lug 42.

[0061] The top of the pole group 4 is covered with an upper support 3.

[0062] The left and right ends of the upper support 3 are respectively provided with a positive electrode through hole 31 and a negative electrode through hole 32.

[0063] Directly above the upper support 3, a battery cover 2 and an outer gasket 1 are arranged in sequence from bottom to top.

[0064] The left and right ends of the battery cover 2 are respectively provided with a positive electrode column mounting hole and a negative electrode column mounting hole.

[0065] A positive electrode column 21 is vertically arranged through the positive electrode column mounting hole.

[0066] A negative electrode column 22 is vertically arranged through the negative electrode column mounting hole.

[0067] The positive electrode lug 41 of the pole group 4 is connected to the lower end of the positive electrode column 21 after being arranged upward through the positive electrode through hole 31 of the upper support 3.

[0068] The negative electrode lug 42 of the pole group 4 is connected to the lower end of the negative electrode column 22 after being arranged upward through the negative electrode through hole 32 of the upper support 3.

[0069] On the top of the battery cover 2, an outer gasket 1 is provided;

[0070] At the left and right ends of the outer gasket 1, a positive electrode post receiving hole 11 and a negative electrode post receiving hole 12 are respectively provided;

[0071] The upper end of the positive electrode post 21 is embedded in the positive electrode post receiving hole 11;

[0072] The upper end of the negative electrode post 22 is embedded in the negative electrode post receiving hole 12;

[0073] Among them, for the multiple outer sides of the electrode group protective sleeve 5 that are used to contact the inner side of the battery case 6 (such as Figure 1 the left outer side, right outer side, front outer side and rear outer side of the electrode group protective sleeve shown), at least one of the outer sides is a matte surface;

[0074] And / or, for the multiple inner sides of the battery case 6 (such as Figure 1 the left inner side, right inner side, front inner side and rear inner side of the battery case 6 shown), at least one of the inner sides is a matte surface.

[0075] In the present invention, specifically, the shapes of the electrode group protective sleeve 5 and the battery case 6 are both rectangular parallelepiped shapes.

[0076] In the present invention, specifically, the shape of the insulating protective tape 7 is a "U" shape;

[0077] The insulating protective tape 7 is pasted on the front and rear sides of the battery case 6.

[0078] In the present invention, specifically, the roughness of the matte surface of the electrode group protective sleeve 5 and the matte surface of the battery case 6 is both 6.3μm ≤ Ra ≤ 100μm. Here, Ra is the arithmetic mean deviation of the profile.

[0079] In the present invention, specifically, when there are matte surfaces on both the outer side of the electrode group protective sleeve 5 and the inner side of the battery case 6, for the matte surface on the electrode group protective sleeve 5 and the matte surface on the battery case 6, it is preferably set in a positive correspondence and in contact with each other to enhance the frictional force and improve the ability to resist external impacts.

[0080] In the present invention, specifically, at the horizontal middle position of the battery cover 2, a safety valve (i.e., a pressure relief valve) is provided through an opening;

[0081] At the position corresponding to the safety valve on the outer gasket 1, a safety valve exposure hole 10 is provided. <G

[0082] In the present invention, specifically, the electrode group protective sleeve 5 is located between the electrode group 4 made by winding or laminating and the battery case 6;

[0083] In specific implementation, the material of the pole group protective sleeve 5 is a material that is corrosion-resistant, high-temperature-resistant, low-temperature-resistant and does not shrink after long-term use, and is preferably a protective sleeve made of PET (polyethylene terephthalate), PP (polypropylene) or PE (polyethylene). The material surface of the pole group protective sleeve 5 is clean and free of oil stains, and the edge (i.e. the edge) is free of burrs.

[0084] In the present application, in specific implementation, the shape of the pole group protective sleeve 5 follows the design requirements of the battery and can be a one-piece protective sleeve or a split protective sleeve.

[0085] In the present application, in specific implementation, the pole group protective sleeve 5 can be provided with a bending mark before being made, so that the pole group protective sleeve can be shaped and processed through the bending mark during processing, achieving rapid processing.

[0086] In the present application, in specific implementation, referring to Figure 2 As shown in the figure, the bottom of the pole group protective sleeve 5 is provided with a plurality of (not limited to Figure 2 three) holes 50 at equal intervals.

[0087] It should be noted that in the present application, the pole group protective sleeve 5 can be provided with holes to ensure the infiltration of the electrolyte into the pole group. The main purpose of the pole group protective sleeve opening is to ensure the absorption of the electrolyte by the pole group, maintain the normal charge and discharge performance of the battery, and improve the life of the battery cell.

[0088] It should be noted that the design of the holes of the pole group protective sleeve is different in different batteries. Whether the pole group protective sleeve is provided with holes depends on the absorption of the electrolyte by the pole group. If the holes are designed, the contact of the electrolyte with the inner wall of the battery shell is a normal condition, because under normal conditions, it will not cause corrosion or leakage of the battery shell.

[0089] It should be noted that in theory, after the pole group protective sleeve is opened, the breakdown voltage between the pole group and the battery shell will be reduced. Therefore, in the case of opening design of the pole group protective sleeve, an insulating gasket can be added inside the battery shell, and a bottom gasket of insulating material can be added at the bottom of the battery shell. To ensure the insulation between the pole group and the battery shell.

[0090] In the present application, in specific implementation, referring to Figure 2 As shown in the figure, the left and right outer sides of the pole group protective sleeve 5 are frosted;

[0091] The frosted area 51 (i.e. the area where frosting exists) of the frosted surface is located at the lower end of the left and right outer sides of the pole group protective sleeve 5.

[0092] In the present application, it is necessary to point out that the pole group of the battery is a conventional pole group design, and the pole group comprises a positive plate, a negative plate and a separator, and the positive plate and the negative plate are respectively located on two sides of the separator.

[0093] The positive plate comprises a positive current collector and a positive mixture mainly composed of an active material, a conductive agent and a binder; the components and component proportions of the positive mixture can be conventional technologies, and will not be described here.

[0094] The negative plate comprises a negative current collector and a negative mixture mainly composed of a negative active material, a negative conductive agent, a negative dispersant and a negative binder; the components and component proportions of the negative mixture can be conventional technologies, and will not be described here.

[0095] In the present application, the positive plate, the negative plate and the separator can be made into the pole group of the battery by a winding process or a stacking process.

[0096] In the present application, the battery shell 6 can be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. The battery shell 6 can also be a soft package, such as a bag type soft package. The material of the soft package can be plastic, and as the plastic, polypropylene, polybutylene terephthalate and polybutylene succinate, etc. can be used.

[0097] In the present application, it is necessary to point out that by setting a frosted surface on the outer side of the pole group protective sleeve and / or the inner side of the battery shell, the friction between the pole group and the inner wall of the battery shell can be significantly increased, the acceleration of the pole group when subjected to external impact can be reduced, the relative sliding between the pole group and the battery shell can be reduced, and the safety performance of the battery can be improved.

[0098] In order to more clearly understand the technical solutions of the present application, the working principle of the present application is described below.

[0099] It is necessary to point out that in the prior art, the pole group protective sleeve is made of a smooth material. The friction between the pole group protective sleeve and the inner wall of the battery shell is very small. Therefore, when the battery is subjected to external impact such as vibration, inverted drop, bumping, etc., the pole group has a great probability of relative displacement in the battery shell. This displacement may increase the pressure near the safety valve in a short time, and then cause the opening of the safety valve. After the safety valve is opened, the risk of spilling of the flammable electrolyte increases, causing serious safety hazards. At the same time, in the process of relative displacement of the pole group, the separator in the battery may be extruded, causing deformation and bending of the separator, and then leading to the loss of the isolation effect of the separator on the positive plate and the negative plate, thereby causing internal short circuit of the battery and battery thermal runaway accident.

[0100] Compared with the prior art, the high-safety lithium ion secondary battery provided by the application can improve the safety performance of the battery from two aspects. Firstly, when the battery is subjected to external impact, the application can increase the friction between the pole group and the battery shell by providing a frosted surface on the pole group protective sleeve 5 and / or the battery shell 6, thereby reducing the acceleration of the pole group when it slides in the battery, avoiding the instantaneous high pressure on the safety valve inside the battery, and reducing the risk of opening of the safety valve and spilling of the electrolyte. Secondly, the application can reduce the displacement of the pole group in the battery shell caused by external impact, thereby avoiding the bending or deformation of the separator. In this way, the application can significantly reduce the probability of contact between the positive electrode plate and the negative electrode plate inside the battery, thereby effectively avoiding the thermal runaway accident of the battery.

[0101] In order to further clearly understand the technical solutions of the application, the working principle and technical effects of the lithium ion battery prepared by the application will be described below in combination with specific examples and comparative examples.

[0102] Examples

[0103] Reference Figure 1 As shown in the drawings, for the application, after the positive electrode plate, the negative electrode plate and the separator are made into a pole group 4 by winding or stacking, the pole group 4 is isolated from the upper support 3 by the separator surrounding the negative electrode plate (the top of the negative electrode plate has an exposed negative electrode tab). When the battery is inverted, the pole group 4 is only supported by the separator between the pole group 4 and the upper support 3, and the supporting force is very small. Figure 2 In order to test the appearance of the pole group protective sleeve of the lithium ion secondary battery, the pole group protective sleeve 5 is located between the pole group 4 and the battery shell 6, and plays a role in protecting the pole group structure. It should be noted that the pole group protective sleeve in the prior art is designed with a smooth surface.

[0104] In the examples of the application, a battery is made using a frosted protective sleeve with Ra=50μm. The battery of the example is subjected to the same inversion drop test as the comparative example, i.e. the battery of the example is placed on the existing drop test device to perform the battery inversion drop test, and the drop height of the battery is set to 1.6m. After the test, the safety valve of the battery is not opened, and there is no phenomenon of electrolyte spilling.

[0105] Comparative example

[0106] The battery as a comparative example is a battery made using a pole group protective sleeve with a smooth surface. For the battery of the comparative example, after the positive electrode plate, the negative electrode plate and the separator are made into a pole group by winding or stacking, the pole group is isolated from the upper support by the separator surrounding the negative electrode plate (the top of the negative electrode plate has an exposed negative electrode tab). When the battery is inverted, the pole group is only supported by the separator between the pole group and the upper support, and the supporting force is very small. The pole group protective sleeve in the prior art is designed with a smooth surface.

[0107] The battery of the comparative example was placed on an existing drop test device to perform a vertical downward inverted drop test. To simulate the actual use, the drop height of the battery was set to 1.6 m. When the battery of the comparative example was inverted, the top end of the electrode group was only supported by the separator, and the support strength was insufficient. When the battery of the comparative example contacted the ground, the electrode group slid further in the direction of the ground (downward direction) in the battery case due to the inability of the separator to support the electrode group, thereby causing the relative displacement of the electrode group and the battery case. When the acceleration of the battery during the inverted drop process is large, this relative displacement can cause the electrode group to exert a high pressure on the electrolyte inside the battery, thereby transmitting a large instantaneous pressure to the safety valve (usually provided on the battery cover) of the battery through hydraulic pressure, and thus possibly causing the safety valve to open, the electrolyte to overflow, and safety hazards. After inspection, the safety valve of the battery of the comparative example was opened after the inverted drop test, and there was a case of electrolyte overflow.

[0108] Figure 3 A front view of a high-safety lithium ion secondary battery provided by the present application (the front view of the battery of the comparative example is the same), Figure 3 The A area in the above figure is the area of the battery of the example and the battery of the comparative example that was X-rayed.

[0109] Figure 4 The X-ray measurement results of the battery of the example after the inverted drop test. Figure 5 The X-ray measurement results of the battery of the comparative example after the inverted drop test.

[0110] In the comparative example and the example, the batteries before and after the drop were respectively subjected to X-Ray (X-ray) tests, and the distance between the electrode group and the battery cover was recorded and compared.

[0111] Referring to Table 1 below, for the battery of the example and the battery of the comparative example, it can be seen from the comparison of the distance between the top end of the negative plate in the battery and the battery cover before and after the inverted drop that the electrode group of the battery of the example did not significantly displace before and after the inverted drop, while the battery of the comparative example displaced about 2.1 mm.

[0112] It should be noted that, Figure 4 The photo of the battery of the example after the drop. Due to the optimization effect in the example, the internal structure of the battery did not change significantly before the test. It can be understood as being basically consistent with the battery that has not been tested.

[0113] Referring to Figure 4 Since the separator 401 has good light transmittance to X-ray, the X-Ray image is not clear and appears light gray without stacking.

[0114] The separator 401 is located between the negative tab 402 and the upper bracket 3, and does not contact the upper bracket 3, as shown in the position. Figure 4 The negative tab 402 is the black part at the bottom. Figure 4 Since the battery cover 2 and the negative tab 402, the negative lug 42 can be clearly photographed. Therefore, in the description of the present patent, the distance between the top end of the negative tab 402 and the battery cover 2 (as shown in Table 1) is selected as the representation of the displacement before and after the drop test. It can be seen from Figure 4 that the separator 401 does not significantly stack or deform. The distance between the top end of the negative tab 402 and the battery cover 2 remains relatively ideal.

[0115] It should be noted that the negative lug 42 in Figure 4 is welded together or integrally formed with the negative tab 402, and is welded on the battery cover by ultrasonic welding or laser welding. The positive lug is the same.

[0116] It should be noted that the bottom of the battery cover 2 has an insulating film 404.

[0117] Referring to Figure 5 , for the comparative battery, after falling, it can be seen that due to the overall upward movement of the pole group, the separator 401 has deformed and stacked, and the negative tab 402 may contact the upper bracket 3. The distance between the upper edge of the negative tab 402 and the battery cover 2 is shortened. The explosion-proof valve position on the battery cover is extruded, causing risks.

[0118] For the comparative battery, it can be seen from Figure 5 that after the inverted drop test, the top of the negative tab inside the pole group of the comparative battery has contacted the upper bracket, and the separator has been bent at this time, which makes the separator lose the ability to isolate and protect the positive and negative tabs, and has a higher risk of internal short circuit and thermal runaway. For the battery of the embodiment, it can be seen from Figure 4 that after the inverted drop test, the top of the negative tab inside the pole group of the battery does not contact the upper bracket, which can effectively avoid the above risks.

[0119] Table 1 Comparison of distance between top end of negative tab and battery cover before and after inverted drop

[0120]

[0121] It should be noted that the operation in the embodiment is only for further illustration of the implementation method of the present application, and does not limit the application range of the present application. In the normal manufacturing, use, storage and testing process, the safety performance of the lithium ion secondary battery can be improved by the technical solution of the present application.

[0122] Compared with the prior art, the lithium ion secondary battery with high safety performance provided by the application has scientific design, can effectively improve the safety performance of the battery when coping with external impacts such as falling, vibration and bumping, further improve the overall safety performance of the lithium ion battery, promote the batch production and application of the lithium ion battery, help improve the market application prospect of the products of the battery production enterprise, and has great production practical significance.

[0123] The above only describes the preferred embodiments of the application, and it should be noted that those skilled in the art can make several improvements and refinements without departing from the principles of the application, and these improvements and refinements should also be considered within the protection scope of the application.

Claims

1. A high-safety lithium-ion secondary battery, characterized in that, The battery includes an outer gasket (1), a battery cover (2), an upper support (3), a pole group (4), a pole group protective sleeve (5), a battery shell (6), and an insulating protective tape (7); The outer surface of the hollow battery shell (6) with a top opening is wrapped with the insulating protective tape (7); A hollow pole group protective sleeve (5) with a top opening is arranged in the inner cavity of the battery shell (6); A pole group (4) is arranged in the inner cavity of the pole group protective sleeve (5); Positive and negative pole ears (41) and (42) are respectively arranged at the top left and right ends of the pole group (4); An upper support (3) is arranged on the top of the pole group (4); Positive and negative pole passing holes (31) and (32) are respectively arranged at the left and right ends of the upper support (3); A battery cover (2) and an outer gasket (1) are sequentially arranged above the upper support (3) from bottom to top; Positive and negative pole column mounting holes are respectively arranged at the left and right ends of the battery cover (2); A safety valve is arranged at the transverse middle position of the battery cover (2); An outer gasket (1) is arranged at the position corresponding to the safety valve; A positive pole column (21) is vertically arranged in the positive pole column mounting hole; A negative pole column (22) is vertically arranged in the negative pole column mounting hole; The positive pole ear (41) of the pole group (4) is connected with the lower end of the positive pole column (21) after passing through the positive pole passing hole (31) of the upper support (3) upward; The negative pole ear (42) of the pole group (4) is connected with the lower end of the negative pole column (22) after passing through the negative pole passing hole (32) of the upper support (3) upward; An outer gasket (1) is arranged on the top of the battery cover (2); Positive and negative pole column accommodating holes (11) and (12) are respectively arranged at the left and right ends of the outer gasket (1); The upper end of the positive pole column (21) is embedded in the positive pole column accommodating hole (11); The upper end of the negative pole column (22) is embedded in the negative pole column accommodating hole (12); At least one of the outer sides of the pole group protective sleeve (5) in contact with the inner side of the battery shell (6) is a frosted surface, and at least one of the inner sides of the battery shell (6) is a frosted surface; When the outer side of the pole group protective sleeve (5) and the inner side of the battery shell (6) both have frosted surfaces, the frosted surfaces of the pole group protective sleeve (5) and the battery shell (6) are in positive correspondence and in contact with each other; The roughness of the frosted surfaces of the pole group protective sleeve (5) and the battery shell (6) is 6.3 μm≤Ra≤100 μm, where Ra is the arithmetic mean deviation of the profile.

2. The high safety lithium ion secondary battery as claimed in claim 1, wherein The shapes of the pole group protective sleeve (5) and the battery shell (6) are both cuboid.

3. The high safety lithium ion secondary battery as claimed in claim 1, wherein The shape of the insulating protective tape (7) is a "N" shape; The insulating protective tape (7) is pasted on the front and back sides of the battery shell (6).

4. The high safety lithium ion secondary battery as claimed in claim 1, wherein The pole group protective sleeve (5) is made of PET, PP, or PE; The battery shell (6) is a hard shell or a soft shell.

5. The high safety lithium ion secondary battery as claimed in claim 1, wherein The material surface of the pole group protective sleeve (5) is clean and free of oil stains, and the edge is free of burrs. The pole group protective sleeve (5) is a one-piece protective sleeve or a split protective sleeve.

6. The high safety lithium ion secondary battery as claimed in claim 1, wherein The bottom of the pole group protection sleeve (5) is provided with a plurality of holes (50) at equal intervals.

7. The high safety lithium-ion secondary battery according to any one of claims 1 to 6, wherein The left and right outer sides of the pole group protection sleeve (5) are frosted surfaces. The frosted area (51) of the frosted surface is located at the lower end of the left and right outer sides of the pole group protection sleeve (5).

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