Secondary battery, electronic equipment and terminal equipment

Abstract

The invention provides a secondary battery, electronic equipment and terminal equipment, and the secondary battery provided by the invention can improve or eliminate the problem of thickness difference between a positive pole lug and a negative pole lug, so that the local pressure of pole pieces around the pole lugs is uniform in the manufacturing and formation process of the secondary battery, the problem of insufficient electrolyte in the later period of circulation is improved, and the service life of the secondary battery is prolonged. Furthermore, the problem of lithium precipitation around the tab is improved, and the cycle life of the secondary battery can be prolonged.

Description

Technical Field

[0001] The present application relates to the field of electrochemical technology, and in particular to a secondary battery, an electronic device and a terminal device. Background Art

[0002] Secondary batteries, such as lithium-ion batteries, are currently widely used in consumer electronic products. Based on people's demand for thinner and lighter consumer electronic products such as mobile phones and laptops, as well as longer battery life, the requirements for the mass energy density and volume energy density of lithium-ion batteries are getting higher and higher.

[0003] Normally, in order to prevent the burrs generated at the welding of the pole ears from piercing the diaphragm and causing a short circuit between the positive and negative electrodes of the lithium-ion battery, insulating protective tape is usually pasted on the negative and positive pole ears. The material of the negative pole ear is generally copper-plated nickel or nickel, and the material of the positive pole ear is generally aluminum. Since the electrical conductivity of copper-plated nickel and nickel is worse than that of aluminum, the thickness of the negative pole ear is generally greater than that of the positive pole ear. As a result, the thickness of the negative pole ear of a two-pole ear secondary battery, a three-pole ear secondary battery or a multi-pole ear secondary battery is greater than the thickness of the positive pole ear. During the manufacturing and formation process of the secondary battery, there is uneven local pressure on the pole piece around the pole ear. When the electrolyte is insufficient in the later stage of the cycle, lithium deposition occurs first at the weak interface around the pole ear, which in turn shortens the cycle life of the secondary battery. Summary of the invention

[0004] The purpose of this application is to provide a secondary battery, an electronic device and a terminal device to improve the lithium deposition around the tabs in the secondary battery, thereby extending the cycle life of the secondary battery. The specific technical solution is as follows:

[0005] It should be noted that in the invention content of the present application, a lithium-ion battery is used as an example of a secondary battery to explain the present application, but the secondary battery of the present application is not limited to a lithium-ion battery.

[0006] The first aspect of the present application provides a secondary battery, which includes a positive electrode sheet, a negative electrode sheet, a separator, a first negative electrode tab insulation tape, a second negative electrode tab insulation tape, a third negative electrode tab insulation tape and a fourth negative electrode tab insulation tape;

[0007] The negative electrode plate comprises a negative electrode current collector and negative electrode material layers arranged on two surfaces of the negative electrode current collector, the negative electrode plate further comprises a negative electrode tab connected to the negative electrode current collector, and the area where the negative electrode current collector and the negative electrode tab are connected is the negative electrode tab area;

[0008] The positive electrode sheet comprises a positive electrode current collector and a positive electrode material layer arranged on two surfaces of the positive electrode current collector;

[0009] The first negative electrode tab insulating adhesive tape is arranged on the surface of the positive electrode material layer opposite to the negative electrode tab region, and the second negative electrode tab insulating adhesive tape is arranged on the surface of the positive electrode material layer opposite to the negative electrode tab region;

[0010] The third negative electrode tab insulation tape is disposed on the surface of the negative electrode material layer on one surface of the negative electrode current collector and covers the negative electrode tab region, and the fourth negative electrode tab insulation tape is disposed on the surface of the negative electrode material layer on the other surface of the negative electrode current collector and is opposite to the third negative electrode tab insulation tape;

[0011] Along the thickness direction of the secondary battery, the first negative electrode tab insulation tape and / or the second negative electrode tab insulation tape are at least partially embedded in the positive electrode material layer, and / or the third negative electrode tab insulation tape and / or the fourth negative electrode tab insulation tape are at least partially embedded in the negative electrode material layer.

[0012] In some embodiments of the present application, the third negative electrode tab insulation paper and the fourth negative electrode tab insulation paper are at least partially embedded in the negative electrode material layer;

[0013] Along the thickness direction of the secondary battery, the thickness H3 of the third negative electrode tab insulation glue embedded in the negative electrode material layer is 5μm to 10μm, and the thickness H4 of the fourth negative electrode tab insulation glue embedded in the negative electrode material layer is 5μm to 10μm; along the width direction of the secondary battery, the width W3 of the third negative electrode tab insulation glue embedded in the negative electrode material layer is 10mm to 16mm, and the width W4 of the fourth negative electrode tab insulation glue embedded in the negative electrode material layer is 10mm to 16mm; along the length direction of the secondary battery, the length L3 of the third negative electrode tab insulation glue embedded in the negative electrode material layer is 10mm to 40mm, and the length L4 of the fourth negative electrode tab insulation glue embedded in the negative electrode material layer is 10mm to 40mm.

[0014] In some embodiments of the present application, L3 is 20 mm to 30 mm, and / or L4 is 20 mm to 30 mm.

[0015] In some embodiments of the present application, the first negative electrode tab insulation paper and the second negative electrode tab insulation paper are at least partially embedded in the positive electrode material layer;

[0016] Along the thickness direction of the secondary battery, the thickness H1 of the first negative electrode tab insulation glue embedded in the positive electrode material layer is 5μm to 10μm, and the thickness H2 of the second negative electrode tab insulation glue embedded in the positive electrode material layer is 5μm to 10μm; along the width direction of the secondary battery, the width W1 of the first negative electrode tab insulation glue embedded in the positive electrode material layer is 10mm to 16mm, and the width W2 of the second negative electrode tab insulation glue embedded in the positive electrode material layer is 10mm to 16mm; along the length direction of the secondary battery, the length L1 of the first negative electrode tab insulation glue embedded in the positive electrode material layer is 10mm to 40mm, and the length L2 of the second negative electrode tab insulation glue embedded in the positive electrode material layer is 10mm to 40mm.

[0017] In some embodiments of the present application, L1 is 20 mm to 30 mm, and / or L2 is 20 mm to 30 mm.

[0018] In some embodiments of the present application, the first negative electrode tab insulation paper and the second negative electrode tab insulation paper are at least partially embedded in the positive electrode material layer, and the third negative electrode tab insulation paper and the fourth negative electrode tab insulation paper are at least partially embedded in the negative electrode material layer;

[0019] Along the thickness direction of the secondary battery, the thickness H1 of the first negative electrode tab insulation glue embedded in the positive electrode material layer is 2.5μm to 5μm; the thickness H2 of the second negative electrode tab insulation glue embedded in the positive electrode material layer is 2.5μm to 5μm; the thickness H3 of the third negative electrode tab insulation glue embedded in the negative electrode material layer is 2.5μm to 5μm, and the thickness H4 of the fourth negative electrode tab insulation glue embedded in the negative electrode material layer is 2.5μm to 5μm;

[0020] Along the width direction of the secondary battery, the width W1 of the first negative electrode tab insulation glue embedded in the positive electrode material layer is 10mm to 16mm, the width W2 of the second negative electrode tab insulation glue embedded in the positive electrode material layer is 10mm to 16mm, the width W3 of the third negative electrode tab insulation glue embedded in the negative electrode material layer is 8mm to 14mm, and the width W4 of the fourth negative electrode tab insulation glue embedded in the negative electrode material layer is 8mm to 14mm;

[0021] Along the length direction of the secondary battery, the length L1 of the first negative electrode tab insulation glue embedded in the positive electrode material layer is 10mm to 40mm, the length L2 of the second negative electrode tab insulation glue embedded in the positive electrode material layer is 10mm to 40mm, the length L3 of the third negative electrode tab insulation glue embedded in the negative electrode material layer is 10mm to 40mm, and the length L4 of the fourth negative electrode tab insulation glue embedded in the negative electrode material layer is 10mm to 40mm.

[0022] In some embodiments of the present application, the secondary battery satisfies at least one of the following characteristics:

[0023] (1) L1 is 20 mm to 30 mm;

[0024] (2) L2 is 20 mm to 30 mm;

[0025] (3) L3 is 20 mm to 30 mm;

[0026] (4) L4 is 20 mm to 30 mm.

[0027] In some embodiments of the present application, the secondary battery further comprises a first positive electrode tab insulating tape, a second positive electrode tab insulating tape, a third positive electrode tab insulating tape and a fourth positive electrode tab insulating tape;

[0028] The positive electrode sheet further includes a positive electrode tab connected to the positive electrode collector, and the area where the positive electrode collector is connected to the positive electrode tab is the positive electrode tab area;

[0029] The first positive electrode tab insulating adhesive tape is arranged on the surface of the negative electrode material layer opposite to the positive electrode tab region, and the second positive electrode tab insulating adhesive tape is arranged on the surface of the negative electrode material layer opposite to the positive electrode tab region; the first positive electrode tab insulating adhesive tape and the second positive electrode tab insulating adhesive tape are at least partially embedded in the negative electrode material layer,

[0030] The third positive electrode tab insulation tape is arranged on the surface of the positive electrode material layer on one surface of the positive electrode current collector and covers the positive electrode tab region, and the fourth positive electrode tab insulation tape is arranged on the surface of the positive electrode material layer on the other surface of the positive electrode current collector and is opposite to the third positive electrode tab insulation tape; the third positive electrode tab insulation tape and the fourth positive electrode tab insulation tape are at least partially embedded in the positive electrode material layer;

[0031] Along the thickness direction of the secondary battery, the thickness of the first negative electrode tab insulation glue embedded in the positive electrode material layer is H1, the thickness of the second negative electrode tab insulation glue embedded in the positive electrode material layer is H2, the thickness of the third negative electrode tab insulation glue embedded in the negative electrode material layer is H3, and the thickness of the fourth negative electrode tab insulation glue embedded in the negative electrode material layer is H4; the thickness of the first positive electrode tab insulation glue embedded in the negative electrode material layer is H5, the thickness of the second positive electrode tab insulation glue embedded in the negative electrode material layer is H6, the thickness of the third positive electrode tab insulation glue embedded in the positive electrode material layer is H7, and the thickness of the fourth positive electrode tab insulation glue embedded in the positive electrode material layer is H8; the difference e between the thickness of the positive electrode tab and the negative electrode tab is 5μm to 20μm; (H1+H2+H3+H4)-(H5+H6+H7+H8)≤e / 2;

[0032] Along the width direction of the secondary battery, the width W1 of the first negative electrode tab insulation glue embedded in the positive electrode material layer is 10mm to 16mm, the width W2 of the second negative electrode tab insulation glue embedded in the positive electrode material layer is 10mm to 16mm, the width W3 of the third negative electrode tab insulation glue embedded in the negative electrode material layer is 8mm to 14mm, and the width W4 of the fourth negative electrode tab insulation glue embedded in the negative electrode material layer is 8mm to 14mm; the width W5 of the first positive electrode tab insulation glue embedded in the negative electrode material layer is 10mm to 16mm, the width W6 of the second positive electrode tab insulation glue embedded in the negative electrode material layer is 10mm to 16mm, the width W7 of the third positive electrode tab insulation glue embedded in the positive electrode material layer is 8mm to 14mm, and the width W8 of the fourth positive electrode tab insulation glue embedded in the positive electrode material layer is 8mm to 14mm;

[0033] Along the length direction of the secondary battery, the length L1 of the first negative electrode tab insulation glue embedded in the positive electrode material layer is 10mm to 40mm, the length L2 of the second negative electrode tab insulation glue embedded in the positive electrode material layer is 10mm to 40mm, the length L3 of the third negative electrode tab insulation glue embedded in the negative electrode material layer is 10mm to 40mm, and the length L4 of the fourth negative electrode tab insulation glue embedded in the negative electrode material layer is 10mm to 40mm; the length L5 of the first positive electrode tab insulation glue embedded in the negative electrode material layer is 10mm to 40mm, the length L6 of the second positive electrode tab insulation glue embedded in the negative electrode material layer is 10mm to 40mm, the length L7 of the third positive electrode tab insulation glue embedded in the positive electrode material layer is 10mm to 40mm, and the length L8 of the fourth positive electrode tab insulation glue embedded in the positive electrode material layer is 10mm to 40mm.

[0034] In some embodiments of the present application, along the thickness direction of the secondary battery, the secondary battery satisfies at least one of the following characteristics:

[0035] (1) H1 is 2.5 μm to 10 μm;

[0036] (2) H2 is 2.5 μm to 10 μm;

[0037] (3) H3 is 2.5 μm to 10 μm;

[0038] (4) H4: 2.5 μm to 10 μm;

[0039] (5) H5 is 2 μm to 5 μm;

[0040] (6) H6: 2 μm to 5 μm;

[0041] (7) H7: 2 μm to 5 μm;

[0042] (8) H8 is 2 μm to 5 μm.

[0043] In some embodiments of the present application, the secondary battery satisfies at least one of the following characteristics:

[0044] (1) L1 is 20 mm to 30 mm;

[0045] (2) L2 is 20 mm to 30 mm;

[0046] (3) L3 is 20 mm to 30 mm;

[0047] (4) L4 is 20 mm to 30 mm;

[0048] (5) L5 is 20 mm to 30 mm;

[0049] (6) L6 is 20 mm to 30 mm;

[0050] (7) L7 is 20 mm to 30 mm;

[0051] (8) L8 is 20 mm to 30 mm.

[0052] A second aspect of the present application provides an electronic device, which includes the secondary battery in any of the aforementioned embodiments.

[0053] A third aspect of the present application provides a terminal device, which includes the electronic device in any of the aforementioned embodiments.

[0054] Beneficial effects of this application:

[0055] The present application provides a secondary battery, an electronic device and a terminal device, wherein the secondary battery comprises a positive electrode sheet, a negative electrode sheet, a separator, a first negative electrode tab insulating adhesive tape, a second negative electrode tab insulating adhesive tape, a third negative electrode tab insulating adhesive tape and a fourth negative electrode tab insulating adhesive tape; the negative electrode sheet comprises a negative electrode current collector and a negative electrode material layer arranged on both surfaces of the negative electrode current collector, the negative electrode sheet also comprises a negative electrode tab connected to the negative electrode current collector, and the area where the negative electrode current collector and the negative electrode tab are connected is the negative electrode tab area; the positive electrode sheet comprises a positive electrode current collector and a positive electrode material layer arranged on both surfaces of the positive electrode current collector; the first negative electrode tab insulating adhesive tape is arranged on the positive electrode tab The positive electrode material layer is opposite to the region, the second negative electrode tab insulation tape is arranged on the positive electrode material layer opposite to the negative electrode tab region; the third negative electrode tab insulation tape is arranged on the negative electrode material layer on one surface of the negative electrode current collector and covers the negative electrode tab region, and the fourth negative electrode tab insulation tape is arranged on the negative electrode material layer on the other surface of the negative electrode current collector and is opposite to the third negative electrode tab insulation tape; along the thickness direction of the secondary battery, the first negative electrode tab insulation tape and / or the second negative electrode tab insulation tape are at least partially embedded in the positive electrode material layer, and / or the third negative electrode tab insulation tape and / or the fourth negative electrode tab insulation tape are at least partially embedded in the negative electrode material layer. Through the above arrangement, the lithium plating problem caused by the thickness difference between the positive electrode tab and the negative electrode tab can be improved, thereby extending the cycle life of the secondary battery.

[0056] Of course, implementing any product or method of the present application does not necessarily require achieving all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application, and for ordinary technicians in this field, other embodiments can also be obtained based on these drawings.

[0058] Figure 1 A schematic diagram of the structure of a secondary battery in one embodiment of the present application;

[0059] Figure 2 A schematic diagram of a partial cross-sectional structure of a secondary battery along its thickness direction in one embodiment of the present application;

[0060] Figure 3 A schematic diagram of a partial cross-sectional structure of a positive electrode sheet along its thickness direction according to an embodiment of the present application;

[0061] Figure 4 A schematic diagram of a partial cross-sectional structure of a positive electrode sheet along its thickness direction according to another embodiment of the present application;

[0062] Figure 5 A schematic diagram of a partial cross-sectional structure of a negative electrode sheet along its thickness direction according to an embodiment of the present application;

[0063] Figure 6 A schematic diagram of a partial cross-sectional structure of a negative electrode sheet along its thickness direction according to another embodiment of the present application;

[0064] Figure 7 A schematic diagram of a partial cross-sectional structure of a secondary battery along its thickness direction in another embodiment of the present application;

[0065] Figure 8 A schematic diagram of a partial structure of a negative electrode sheet in one embodiment of the present application;

[0066] Fig. 9 A schematic diagram of a partial structure of a positive electrode sheet in one embodiment of the present application;

[0067] Fig.10 This is a schematic diagram of a partial cross-sectional structure of a secondary battery along its thickness direction in another embodiment of the present application;

[0068] Fig.11 It is a schematic diagram of the partial cross-sectional structure of a secondary battery along its thickness direction in another embodiment of the present application. DETAILED DESCRIPTION

[0069] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those skilled in the art based on the present application belong to the scope of protection of the present application.

[0070] It should be noted that in the specific implementation manner of the present application, the present application is explained by taking a lithium-ion battery as an example of a secondary battery, but the secondary battery of the present application is not limited to a lithium-ion battery.

[0071] For ease of understanding, Figure 1 As shown, a three-dimensional rectangular coordinate system is established with the width direction of the secondary battery 10 as the X direction, the length direction as the Y direction, and the thickness direction as the Z direction. In the present application, the width direction of the positive electrode sheet, the negative electrode sheet, and the separator in the secondary battery is the same as the width direction of the secondary battery, the length direction of the positive electrode sheet, the negative electrode sheet, and the separator is the same as the length direction of the secondary battery, and the thickness direction of the positive electrode sheet, the negative electrode sheet, and the separator is the same as the thickness direction of the secondary battery.

[0072] The first aspect of the present application provides a secondary battery, such as Figure 1 and Figure 2As shown, the secondary battery 10 includes a positive electrode sheet 100, a negative electrode sheet 200, a separator 300, a first negative electrode tab insulating adhesive tape 251, a second negative electrode tab insulating adhesive tape 252, a third negative electrode tab insulating adhesive tape 253 and a fourth negative electrode tab insulating adhesive tape 254. The positive electrode sheet 100 includes a positive electrode collector 110 and a positive electrode material layer 120 disposed on both surfaces of the positive electrode collector 110; the negative electrode sheet 200 includes a negative electrode collector 210 and a negative electrode material layer 220 disposed on both surfaces of the negative electrode collector 210, and the negative electrode sheet 200 also includes a negative electrode tab 230 connected to the negative electrode collector 210, and the area where the negative electrode collector 210 and the negative electrode tab 230 are connected is the negative electrode tab area 240. The first negative electrode tab insulating adhesive tape 251 is disposed on the surface of the positive electrode material layer 120 opposite to the negative electrode tab region 240, and the second negative electrode tab insulating adhesive tape 252 is disposed on the surface of the positive electrode material layer 120 opposite to the negative electrode tab region 240. The third negative electrode tab insulating adhesive tape 253 is disposed on the surface of the negative electrode material layer 220 on one surface 211 of the negative electrode current collector 210 and covers the negative electrode tab region 240, and the fourth negative electrode tab insulating adhesive tape 254 is disposed on the surface of the negative electrode material layer 220 on the other surface 212 of the negative electrode current collector 210 and is opposite to the third negative electrode tab insulating adhesive tape 253.

[0073] In the present application, the above-mentioned “the first negative electrode tab insulating adhesive tape 251 is arranged on the surface of the positive electrode material layer 120 opposite to the negative electrode tab region 240” means that the negative electrode tab region 240 is arranged on a surface 211 of the negative electrode current collector 210, and the negative electrode material layer 220 on the surface is adjacent to the positive electrode material layer 120 on which the first negative electrode tab insulating adhesive tape 251 is arranged, and there is only one layer of separator 300 between the two. Moreover, along the Z direction, the orthographic projection of the first negative electrode tab insulating adhesive tape 251 on the separator 300 covers the orthographic projection of the negative electrode tab region 240 on the separator 300.

[0074] In the present application, the above-mentioned “the second negative electrode tab insulating adhesive tape 252 is arranged on the surface of the positive electrode material layer 120 opposite to the negative electrode tab region 240” means that the surface of the negative electrode current collector 210 opposite to the negative electrode tab region 240 is another surface 212 of the negative electrode current collector 210, and the negative electrode material layer 220 on this surface is adjacent to the positive electrode material layer 120 on which the second negative electrode tab insulating adhesive tape 252 is arranged, and there is only one layer of separator 300 between the two. Moreover, along the Z direction, the positive projection of the second negative electrode tab insulating adhesive tape 252 on the separator 300 covers the positive projection of the negative electrode tab region 240 on the separator 300.

[0075] In the present application, the above-mentioned “the third negative electrode tab insulating adhesive tape 253 is disposed on the surface of the negative electrode material layer 220 on one surface 211 of the negative electrode current collector 210 and covers the negative electrode tab region 240” means that the negative electrode material layer 220 on which the third negative electrode tab insulating adhesive tape 253 is disposed is adjacent to the positive electrode material layer 120 on which the first negative electrode tab insulating adhesive tape 251 is disposed, and there is only one layer of separator 300 between the two. It should be understood that the third negative electrode tab insulating adhesive tape 253 is partially disposed on the surface of the negative electrode material layer 220, partially disposed on the surface of the negative electrode tab 230, and partially disposed on one surface 211 of the negative electrode current collector 210, so that the third negative electrode tab insulating adhesive tape 253 can cover the negative electrode tab region 240 while being disposed on the surface of the negative electrode material layer 220 on one surface 211 of the negative electrode current collector 210.

[0076] In the present application, the above-mentioned “the fourth negative electrode tab insulation tape 254 is disposed on the surface of the negative electrode material layer 220 on the other surface 212 of the negative electrode current collector 210 and is opposite to the third negative electrode tab insulation tape 253” means that the negative electrode material layer 220 on which the fourth negative electrode tab insulation tape 254 is disposed is adjacent to the positive electrode material layer 120 on which the second negative electrode tab insulation tape 252 is disposed, and there is only one layer of separator 300 between the two. The fourth negative electrode tab insulation tape 254 and the third negative electrode tab insulation tape 253 are opposite to each other, which means that along the Z direction, the orthographic projections of the fourth negative electrode tab insulation tape 254 and the third negative electrode tab insulation tape 253 on the negative electrode current collector 210 completely overlap or partially overlap.

[0077] In some embodiments of the present application, along the thickness direction of the secondary battery, the first negative electrode tab insulation tape and / or the second negative electrode tab insulation tape are at least partially embedded in the positive electrode material layer, that is, the first negative electrode tab insulation tape and / or the second negative electrode tab insulation tape can be completely embedded in the positive electrode material layer, or partially embedded in the positive electrode material layer. Specifically, Figure 3 As shown, along the Z direction, the first negative electrode tab insulation tape 251 is completely embedded in the positive electrode material layer 120, that is, the surface of the first negative electrode tab insulation tape 251 is flush with the surface of the positive electrode material layer 120. It can be understood that when the first negative electrode tab insulation tape is completely embedded in the positive electrode material layer, the surface of the positive electrode material layer may also exceed the surface of the first negative electrode tab insulation tape. Figure 4 As shown, along the Z direction, the first negative electrode tab insulation tape 251 is partially embedded in the positive electrode material layer 120. It should be understood that the second negative electrode tab insulation tape can also be fully or partially embedded in the positive electrode material layer, or the first negative electrode tab insulation tape and the second negative electrode tab insulation tape are fully or partially embedded in the positive electrode material layer at the same time.

[0078] In some embodiments of the present application, along the thickness direction of the secondary battery, the third negative electrode tab insulation tape and / or the fourth negative electrode tab insulation tape are at least partially embedded in the negative electrode material layer, that is, the third negative electrode tab insulation tape and / or the fourth negative electrode tab insulation tape can be fully embedded in the negative electrode material layer, or partially embedded in the negative electrode material layer. Specifically, Figure 5 As shown, along the Z direction, the third negative electrode tab insulation tape 253 and the fourth negative electrode tab insulation tape 254 are all embedded in the negative electrode material layer 220, that is, the surfaces of the third negative electrode tab insulation tape 253 and the fourth negative electrode tab insulation tape 254 are respectively flush with the surface of the negative electrode material layer 220. It can be understood that when the third negative electrode tab insulation tape and the fourth negative electrode tab insulation tape are all embedded in the negative electrode material layer, the surface of the negative electrode material layer 220 exceeds the surface of the third negative electrode tab insulation tape and the fourth negative electrode tab insulation tape. Figure 6 As shown, along the Z direction, the third negative electrode tab insulation paper 253 and the fourth negative electrode tab insulation paper 254 are partially embedded in the negative electrode material layer 220. It should be understood that one of the third negative electrode tab insulation paper and the fourth negative electrode tab insulation paper may be fully or partially embedded in the negative electrode material layer.

[0079] In some embodiments of the present application, along the thickness direction of the secondary battery, the first negative electrode tab insulation paper and / or the second negative electrode tab insulation paper are at least partially embedded in the positive electrode material layer, and the third negative electrode tab insulation paper and / or the fourth negative electrode tab insulation paper are at least partially embedded in the negative electrode material layer. That is, all or part of the first negative electrode tab insulation paper and / or the second negative electrode tab insulation paper are embedded in the positive electrode material layer, and all or part of the third negative electrode tab insulation paper and / or the fourth negative electrode tab insulation paper are embedded in the negative electrode material layer.

[0080] Along the thickness direction of the secondary battery, the first negative electrode tab insulation tape and / or the second negative electrode tab insulation tape are at least partially embedded in the positive electrode material layer, and / or the third negative electrode tab insulation tape and / or the fourth negative electrode tab insulation tape are at least partially embedded in the negative electrode material layer. Through the above arrangement, the problem of thickness difference between the positive electrode tab and the negative electrode tab can be improved or eliminated, so that the local pressure of the pole piece around the tab is uniform during the secondary battery manufacturing formation process, the problem of insufficient electrolyte in the late cycle is improved, and then the problem of lithium precipitation around the tab is improved, which can extend the cycle life of the secondary battery. In addition, the problem of thickness difference between the positive electrode tab and the negative electrode tab is improved, which can improve the consistency of the secondary battery structure and reduce the volume of the secondary battery, thereby facilitating the improvement of the energy density of the secondary battery.

[0081] In some embodiments of the present application, the third negative electrode tab insulation tape and the fourth negative electrode tab insulation tape are at least partially embedded in the negative electrode material layer. That is, the third negative electrode tab insulation tape and the fourth negative electrode tab insulation tape are completely embedded in the negative electrode material layer, or the third negative electrode tab insulation tape and the fourth negative electrode tab insulation tape are partially embedded in the negative electrode material layer. Specifically, Figure 7 As shown, the third negative electrode tab insulation paper 253 and the fourth negative electrode tab insulation paper 254 are all embedded in the negative electrode material layer 220, and the first negative electrode tab insulation paper 251 and the second negative electrode tab insulation paper 252 are not embedded in the positive electrode material layer. Figure 5 and Figure 8 As shown, along the Z direction, the thickness of the third negative electrode tab insulation tape 253 embedded in the negative electrode material layer 220 is H3; along the X direction, the width of the third negative electrode tab insulation tape 253 embedded in the negative electrode material layer 220 is W3; along the Y direction, the length of the third negative electrode tab insulation tape 253 embedded in the negative electrode material layer 220 is L3. It should be understood that the meanings of the thickness H4, width W4 and length L4 of the fourth negative electrode tab insulation tape embedded in the negative electrode material layer correspond to the meanings of the above H3, W3 and L3, respectively, and can be referred to Figure 5 and Figure 8 For your understanding, this application will not go into details one by one.

[0082] In some embodiments of the present application, the third negative electrode tab insulation tape and the fourth negative electrode tab insulation tape are at least partially embedded in the negative electrode material layer. Along the thickness direction of the secondary battery, H3 is 5μm to 10μm, and H4 is 5μm to 10μm; along the width direction of the secondary battery, W3 is 10mm to 16mm, and W4 is 10mm to 16mm; along the length direction of the secondary battery, L3 is 10mm to 40mm, preferably, L3 is 20mm to 30mm; L4 is 10mm to 40mm, preferably, L4 is 20mm to 30mm. For example, H3 can be 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, or a range consisting of any two values ​​therebetween. For example, H4 can be 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, or a range consisting of any two values ​​therebetween. For example, W3 can be 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, or a range consisting of any two values ​​therebetween. For example, W4 can be 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, or a range consisting of any two values ​​therebetween. For example, L3 can be 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, or a range consisting of any two values ​​therebetween. For example, L4 can be 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, or a range consisting of any two values ​​therebetween.

[0083] In some embodiments of the present application, the first negative electrode tab insulation tape and the second negative electrode tab insulation tape are at least partially embedded in the positive electrode material layer. That is, the first negative electrode tab insulation tape and the second negative electrode tab insulation tape are fully embedded in the positive electrode material layer, or the first negative electrode tab insulation tape and the second negative electrode tab insulation tape are partially embedded in the positive electrode material layer. Specifically, Figure 2 As shown, the first negative electrode tab insulation paper 251 and the second negative electrode tab insulation paper 252 are all embedded in the positive electrode material layer 120, and the third negative electrode tab insulation paper 253 and the fourth negative electrode tab insulation paper 254 are not embedded in the negative electrode material layer. Figure 3 and Fig. 9 As shown, along the Z direction, the thickness of the first negative electrode tab insulation tape 251 embedded in the positive electrode material layer 120 is H1; along the X direction, the width of the first negative electrode tab insulation tape 251 embedded in the positive electrode material layer 120 is W1; along the Y direction, the length of the first negative electrode tab insulation tape 251 embedded in the positive electrode material layer 120 is L1. It should be understood that the meanings of the thickness H2, width W2 and length L2 of the second negative electrode tab insulation tape embedded in the positive electrode material layer correspond to the meanings of the above H1, W1 and L1, respectively, and can be referred to Figure 3 and Fig. 9 For your understanding, this application will not go into details one by one.

[0084] In some embodiments of the present application, the first negative electrode tab insulation tape and the second negative electrode tab insulation tape are at least partially embedded in the positive electrode material layer. Along the thickness direction of the secondary battery, H1 is 5μm to 10μm, and H2 is 5μm to 10μm; along the width direction of the secondary battery, W1 is 10mm to 16mm, and W2 is 10mm to 16mm; along the length direction of the secondary battery, L1 is 10mm to 40mm, preferably, L1 is 20mm to 30mm; L2 is 10mm to 40mm, preferably, L2 is 20mm to 30mm. For example, H1 can be 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, or a range consisting of any two values ​​therebetween. For example, H2 can be 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, or a range consisting of any two values ​​therebetween. For example, W1 can be 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, or a range consisting of any two values ​​therebetween. For example, W2 can be 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, or a range consisting of any two values ​​therebetween. For example, L1 can be 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, or a range consisting of any two values ​​therebetween. For example, L2 can be 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, or a range consisting of any two values ​​therebetween.

[0085] In some embodiments of the present application, the first negative electrode tab insulation paper and the second negative electrode tab insulation paper are at least partially embedded in the positive electrode material layer, and the third negative electrode tab insulation paper and the fourth negative electrode tab insulation paper are at least partially embedded in the negative electrode material layer. That is, the first negative electrode tab insulation tape and the second negative electrode tab insulation tape are all embedded in the positive electrode material layer, and the third negative electrode tab insulation tape and the fourth negative electrode tab insulation tape are all embedded in the negative electrode material layer; or, the first negative electrode tab insulation tape and the second negative electrode tab insulation tape are all embedded in the positive electrode material layer, and the third negative electrode tab insulation tape and the fourth negative electrode tab insulation tape are partially embedded in the negative electrode material layer; or, the first negative electrode tab insulation tape and the second negative electrode tab insulation tape are partially embedded in the positive electrode material layer, and the third negative electrode tab insulation tape and the fourth negative electrode tab insulation tape are partially embedded in the negative electrode material layer; or, the first negative electrode tab insulation tape and the second negative electrode tab insulation tape are partially embedded in the positive electrode material layer, and the third negative electrode tab insulation tape and the fourth negative electrode tab insulation tape are all embedded in the negative electrode material layer. Specifically, Fig.10 As shown, the first negative electrode tab insulation paper 251 and the second negative electrode tab insulation paper 252 are all embedded in the positive electrode material layer 120 , and the third negative electrode tab insulation paper 253 and the fourth negative electrode tab insulation paper 254 are all embedded in the negative electrode material layer 220 .

[0086] In some embodiments of the present application, the first negative electrode tab insulation paper and the second negative electrode tab insulation paper are at least partially embedded in the positive electrode material layer, and the third negative electrode tab insulation paper and the fourth negative electrode tab insulation paper are at least partially embedded in the negative electrode material layer. Specifically, along the thickness direction of the secondary battery, H1 is 2.5μm to 5μm, H2 is 2.5μm to 5μm, H3 is 2.5μm to 5μm, and H4 is 2.5μm to 5μm; along the width direction of the secondary battery, W1 is 10mm to 16mm, W2 is 10mm to 16mm, W3 is 8mm to 14mm, and W4 is 8mm to 14mm; along the length direction of the secondary battery, L1 is 10mm to 40mm, preferably, L1 is 20mm to 30mm; L2 is 10mm to 40mm, preferably, L2 is 20mm to 30mm; L3 is 10mm to 40mm, preferably, L3 is 20mm to 30mm; L4 is 10mm to 40mm, preferably, L4 is 20mm to 30mm. For example, H1 can be 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, or a range consisting of any two values ​​therebetween. For example, H2 can be 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, or a range consisting of any two values ​​therebetween. For example, H3 can be 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, or a range consisting of any two values ​​therebetween. For example, H4 can be 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, or a range consisting of any two values ​​therebetween. For example, W1 can be 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, or a range consisting of any two values ​​therebetween. For example, W2 can be 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, or a range consisting of any two values ​​therebetween. For example, W3 can be 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, or a range consisting of any two values ​​therebetween. For example, W4 can be 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, or a range consisting of any two values ​​therebetween. For example, L1 can be 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, or a range consisting of any two values ​​therebetween. For example, L2 can be 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, or a range consisting of any two values ​​therebetween. For example, L3 may be 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, or a range consisting of any two values ​​therebetween.For example, L4 may be 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, or a range consisting of any two values ​​therebetween.

[0087] In some embodiments of the present application, Fig.11 As shown, the secondary battery 10 further includes a first positive electrode tab insulating adhesive tape 151, a second positive electrode tab insulating adhesive tape 152, a third positive electrode tab insulating adhesive tape 153 and a fourth positive electrode tab insulating adhesive tape 154. The positive electrode sheet 100 further includes a positive electrode tab 130 connected to the positive electrode current collector 110, and the area where the positive electrode current collector 110 is connected to the positive electrode tab 130 is the positive electrode tab area 140. The first positive electrode tab insulating adhesive tape 151 is arranged on the surface of the negative electrode material layer 220 opposite to the positive electrode tab area 140, and the second positive electrode tab insulating adhesive tape 152 is arranged on the surface of the negative electrode material layer 220 opposite to the positive electrode tab area 140. The third positive electrode tab insulating tape 153 is arranged on the surface of the positive electrode material layer 120 on one surface 111 of the positive electrode collector 110 and covers the positive electrode tab area 140. The fourth positive electrode tab insulating tape 154 is arranged on the surface of the positive electrode material layer 120 on the other surface 112 of the positive electrode collector 110 and is opposite to the third positive electrode tab insulating tape 153.

[0088] In the present application, the above-mentioned “the first positive electrode tab insulating adhesive tape 151 is arranged on the surface of the negative electrode material layer 220 opposite to the positive electrode tab region 140” means that the positive electrode tab region 140 is arranged on a surface 111 of the positive electrode current collector 110, and the positive electrode material layer 120 on the surface is adjacent to the negative electrode material layer 220 on which the first positive electrode tab insulating adhesive tape 151 is arranged, and there is only one layer of separator 300 between the two. Moreover, along the Z direction, the orthographic projection of the first positive electrode tab insulating adhesive tape 151 on the separator 300 covers the orthographic projection of the positive electrode tab region 140 on the separator 300.

[0089] In the present application, the above-mentioned “the second positive electrode tab insulating adhesive tape 152 is arranged on the surface of the negative electrode material layer 220 opposite to the positive electrode tab region 140” means that the surface of the positive electrode current collector 110 opposite to the positive electrode tab region 140 is another surface 112 of the positive electrode current collector 110, and the positive electrode material layer 120 on the surface is adjacent to the negative electrode material layer 220 on which the second positive electrode tab insulating adhesive tape 152 is arranged, and there is only one layer of separator 300 between the two. Moreover, along the Z direction, the orthographic projection of the second positive electrode tab insulating adhesive tape 152 on the separator 300 covers the orthographic projection of the positive electrode tab region 140 on the separator 300.

[0090] In the present application, the above-mentioned “the third positive electrode tab insulating adhesive tape 153 is disposed on the surface of the positive electrode material layer 120 on one surface 111 of the positive electrode current collector 110 and covers the positive electrode tab region 140” means that the positive electrode material layer 120 on which the third positive electrode tab insulating adhesive tape 153 is disposed is adjacent to the negative electrode material layer 220 on which the first positive electrode tab insulating adhesive tape 151 is disposed, and there is only one layer of separator 300 between the two. It should be understood that the third positive electrode tab insulating adhesive tape 153 is partially disposed on the surface of the positive electrode material layer 120, partially disposed on the surface of the positive electrode tab 130, and partially disposed on one surface 111 of the positive electrode current collector 110, so that the third positive electrode tab insulating adhesive tape 153 can cover the negative electrode tab region 240 while being disposed on the surface of the positive electrode material layer 120 on one surface 111 of the positive electrode current collector 110.

[0091] In the present application, the above-mentioned “the fourth positive electrode tab insulating tape 154 is disposed on the surface of the positive electrode material layer 120 on the other surface 112 of the positive electrode current collector 110 and is opposite to the third positive electrode tab insulating tape 153” means that the positive electrode material layer 120 on which the fourth positive electrode tab insulating tape 154 is disposed is adjacent to the negative electrode material layer 220 on which the second positive electrode tab insulating tape 152 is disposed, and there is only one layer of separator 300 between the two. The fourth positive electrode tab insulating tape 154 and the third positive electrode tab insulating tape 153 are opposite to each other, which means that along the Z direction, the orthographic projections of the fourth positive electrode tab insulating tape 154 and the third positive electrode tab insulating tape 153 on the positive electrode current collector 110 completely overlap or partially overlap.

[0092] In some embodiments of the present application, along the thickness direction of the secondary battery, the first positive electrode tab insulation tape and the second positive electrode tab insulation tape are at least partially embedded in the negative electrode material layer, and the third positive electrode tab insulation tape and the fourth positive electrode tab insulation tape are at least partially embedded in the positive electrode material layer. That is, the first positive electrode tab insulation tape and the second positive electrode tab insulation tape are all embedded in the negative electrode material layer, and the third positive electrode tab insulation tape and the fourth positive electrode tab insulation tape are all embedded in the positive electrode material layer; or, the first positive electrode tab insulation tape and the second positive electrode tab insulation tape are all embedded in the negative electrode material layer, and the third positive electrode tab insulation tape and the fourth positive electrode tab insulation tape are partially embedded in the positive electrode material layer; or, the first positive electrode tab insulation tape and the second positive electrode tab insulation tape are partially embedded in the negative electrode material layer, and the third positive electrode tab insulation tape and the fourth positive electrode tab insulation tape are partially embedded in the positive electrode material layer; or, the first positive electrode tab insulation tape and the second positive electrode tab insulation tape are partially embedded in the negative electrode material layer, and the third positive electrode tab insulation tape and the fourth positive electrode tab insulation tape are all embedded in the positive electrode material layer. Specifically, Fig.11As shown, the first positive electrode tab insulation tape 151 and the second positive electrode tab insulation tape 152 are all embedded in the negative electrode material layer 220 , and the third positive electrode tab insulation tape 153 and the fourth positive electrode tab insulation tape 154 are all embedded in the positive electrode material layer 120 .

[0093] In some embodiments of the present application, the first negative electrode tab insulation tape and the second negative electrode tab insulation tape are at least partially embedded in the positive electrode material layer, and the third negative electrode tab insulation tape and the fourth negative electrode tab insulation tape are at least partially embedded in the negative electrode material layer; the first positive electrode tab insulation tape and the second positive electrode tab insulation tape are at least partially embedded in the negative electrode material layer, and the third positive electrode tab insulation tape and the fourth positive electrode tab insulation tape are at least partially embedded in the positive electrode material layer.

[0094] Specifically, along the thickness direction of the secondary battery, the thickness of the first negative electrode tab insulation glue embedded in the positive electrode material layer is H1, the thickness of the second negative electrode tab insulation glue embedded in the positive electrode material layer is H2, the thickness of the third negative electrode tab insulation glue embedded in the negative electrode material layer is H3, and the thickness of the fourth negative electrode tab insulation glue embedded in the negative electrode material layer is H4; the thickness of the first positive electrode tab insulation glue embedded in the negative electrode material layer is H5, the thickness of the second positive electrode tab insulation glue embedded in the negative electrode material layer is H6, the thickness of the third positive electrode tab insulation glue embedded in the positive electrode material layer is H7, and the thickness of the fourth positive electrode tab insulation glue embedded in the positive electrode material layer is H8; the difference e between the thickness of the positive electrode tab and the negative electrode tab is 5μm to 20μm, preferably, e is 8μm to 15μm; (H1+H2+H3+H4)-(H5+H6+H7+H8)≤e / 2. For example, e can be 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm, 20μm, or a range consisting of any two values ​​therebetween. Among them, H5 has a similar meaning to H1, and H6 has a similar meaning to H2. Figure 3 and Fig. 9 H7 has a similar meaning to H3, and H8 has a similar meaning to H4. Figure 5 and Figure 8 For your understanding, this application will not go into details one by one.

[0095] Along the width direction of the secondary battery, the width W1 of the first negative electrode tab insulation glue embedded in the positive electrode material layer is 10mm to 16mm, the width W2 of the second negative electrode tab insulation glue embedded in the positive electrode material layer is 10mm to 16mm, the width W3 of the third negative electrode tab insulation glue embedded in the negative electrode material layer is 8mm to 14mm, and the width W4 of the fourth negative electrode tab insulation glue embedded in the negative electrode material layer is 8mm to 14mm; the width W5 of the first positive electrode tab insulation glue embedded in the negative electrode material layer is 10mm to 16mm, the width W6 of the second positive electrode tab insulation glue embedded in the negative electrode material layer is 10mm to 16mm, the width W7 of the third positive electrode tab insulation glue embedded in the positive electrode material layer is 8mm to 14mm, and the width W8 of the fourth positive electrode tab insulation glue embedded in the positive electrode material layer is 8mm to 14mm. For example, W1 can be 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, or a range consisting of any two values ​​therebetween. For example, W2 can be 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm or a range consisting of any two values ​​therebetween. For example, W3 can be 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm or a range consisting of any two values ​​therebetween. For example, W4 can be 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm or a range consisting of any two values ​​therebetween. W5 can be 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm or a range consisting of any two values ​​therebetween. For example, W6 can be 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm or a range consisting of any two values ​​therebetween. For example, W7 can be 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm or a range consisting of any two values ​​therebetween. For example, W8 can be 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm or a range of any two values ​​therebetween. Among them, W5 has a similar meaning to W1, and W6 has a similar meaning to W2. Figure 3 and Fig. 9 W7 and W3 have similar meanings, and W8 and W4 have similar meanings. Figure 5 and Figure 8 For your understanding, this application will not go into details one by one.

[0096] Along the length direction of the secondary battery, the length L1 of a negative electrode tab insulation glue embedded in the positive electrode material layer is 10mm to 40mm, preferably, L1 is 20mm to 30mm; the length L2 of a second negative electrode tab insulation glue embedded in the positive electrode material layer is 10mm to 40mm, preferably, L2 is 20mm to 30mm; the length L3 of a third negative electrode tab insulation glue embedded in the negative electrode material layer is 10mm to 40mm, preferably, L3 is 20mm to 30mm; the length L4 of a fourth negative electrode tab insulation glue embedded in the negative electrode material layer is 10mm to 40mm, preferably, L4 is 20mm to 30mm. The length L5 of the first positive pole tab insulation glue embedded in the negative electrode material layer is 10mm to 40mm, preferably, L5 is 20mm to 30mm; the length L6 of the second positive pole tab insulation glue embedded in the negative electrode material layer is 10mm to 40mm, preferably, L6 is 20mm to 30mm; the length L7 of the third positive pole tab insulation glue embedded in the positive electrode material layer is 10mm to 40mm, preferably, L7 is 20mm to 30mm; the length L8 of the fourth positive pole tab insulation glue embedded in the positive electrode material layer is 10mm to 40mm, preferably, L8 is 20mm to 30mm. For example, L1 can be 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm or a range consisting of any two values ​​therebetween. For example, L2 can be 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm or a range consisting of any two values ​​therebetween. For example, L3 can be 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, or a range consisting of any two values ​​therebetween. For example, L4 can be 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, or a range consisting of any two values ​​therebetween. For example, L5 can be 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, or a range consisting of any two values ​​therebetween. For example, L6 can be 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, or a range consisting of any two values ​​therebetween. For example, L7 can be 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, or a range consisting of any two values ​​therebetween. For example, L8 may be 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, or a range consisting of any two values ​​therebetween.

[0097] In some embodiments of the present application, H1 is 2.5 μm to 10 μm. For example, H1 can be 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, or a range consisting of any two values ​​therebetween. In some embodiments of the present application, H2 is 2.5 μm to 10 μm. For example, H2 can be 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, or a range consisting of any two values ​​therebetween. In some embodiments of the present application, H3 is 2.5 μm to 10 μm. For example, H3 can be 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, or a range consisting of any two values ​​therebetween. In some embodiments of the present application, H4 is 2.5 μm to 10 μm. For example, H4 can be 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, or a range consisting of any two values ​​therebetween. In some embodiments of the present application, H5 is 2 μm to 5 μm. For example, H5 can be 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, or a range consisting of any two values ​​therebetween. In some embodiments of the present application, H6 is 2 μm to 5 μm. For example, H6 can be 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, or a range consisting of any two values ​​therebetween. In some embodiments of the present application, H7 is 2 μm to 5 μm. For example, H7 can be 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, or a range consisting of any two values ​​therebetween. In some embodiments of the present application, H8 is 2 μm to 5 μm. For example, H8 can be 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, or a range consisting of any two values ​​therebetween.

[0098] In the present application, at least two of the above features H1, H2, H3, H4, H5, H6, H7, and H8 can be combined arbitrarily as long as the purpose of the present application can be achieved.

[0099] In the present application, the first negative electrode tab insulation tape, the second negative electrode tab insulation tape, the third negative electrode tab insulation tape, the fourth negative electrode tab insulation tape, the first positive electrode tab insulation tape, the second positive electrode tab insulation tape, the third positive electrode tab insulation tape and the fourth positive electrode tab insulation tape are all conventional tapes known in the art, and the present application does not limit this. The present application does not particularly limit the method of embedding the above-mentioned tape into the positive electrode material layer and / or the negative electrode material layer, as long as the purpose of the present application can be achieved. For example, taking the first negative electrode tab insulation tape as an example, a groove is first provided on the surface of the positive electrode material layer, and then the first negative electrode tab insulation tape is provided in the groove, the depth of the groove corresponds to the thickness H1 of the first negative electrode tab insulation tape embedded in the positive electrode material layer, the width of the groove corresponds to the width W1 of the first negative electrode tab insulation tape embedded in the positive electrode material layer, and the length of the groove corresponds to the length L1 of the first negative electrode tab insulation tape embedded in the positive electrode material layer. The second negative electrode tab insulation tape, the third negative electrode tab insulation tape, the fourth negative electrode tab insulation tape, the first positive electrode tab insulation tape, the second positive electrode tab insulation tape, the third positive electrode tab insulation tape and the fourth positive electrode tab insulation tape are arranged according to the first negative electrode tab insulation tape arrangement method, and this application will not go into details one by one.

[0100] The present application has no particular restrictions on the method for setting the above grooves, as long as the purpose of the present application can be achieved. For example, the grooves can be set by laser cleaning; the grooves can also be set by scraping the positive electrode material layer or negative electrode material layer in the corresponding area with a scraper; or the positive electrode material layer or negative electrode material layer can be coated by gap coating in the preparation process of the positive electrode sheet or negative electrode sheet, so as to directly obtain the positive electrode material layer or negative electrode material layer with grooves.

[0101] The present application has no particular restriction on the thickness of the first negative electrode tab insulation tape, the second negative electrode tab insulation tape, the third negative electrode tab insulation tape, the fourth negative electrode tab insulation tape, the first positive electrode tab insulation tape, the second positive electrode tab insulation tape, the third positive electrode tab insulation tape and the fourth positive electrode tab insulation tape, as long as the purpose of the present application can be achieved. For example, the thickness of the above-mentioned insulation tapes is independently selected from 6μm to 15μm.

[0102] In some embodiments of the present application, the difference e between the thickness of the positive electrode tab and the negative electrode tab is 5 μm to 20 μm, preferably, e is 8 μm to 15 μm. The present application has no particular limitation on the thickness of the positive electrode tab, as long as the purpose of the present application can be achieved. For example, the thickness of the positive electrode tab can be 70 μm to 90 μm, and the thickness of the negative electrode tab can be 90 μm to 110 μm.

[0103] The present application has no particular limitation on the thickness of the positive electrode material layer and the negative electrode material layer, as long as the purpose of the present application can be achieved. For example, the thickness of the positive electrode material layer can be 60 μm to 100 μm, and the thickness of the negative electrode material layer can be 60 μm to 100 μm.

[0104] In the present application, the positive electrode tab, the negative electrode tab, the positive electrode current collector, the negative electrode current collector and the separator may be conventional positive electrode tabs, negative electrode tabs, positive electrode current collector, negative electrode current collector and separator in the art, and the present application does not limit this. The composition of the positive electrode material layer and the negative electrode material layer may also be conventional positive electrode material layer and negative electrode material layer in the art, and the present application does not limit this.

[0105] In the present application, the secondary battery may also include other necessary or optional components or materials in addition to the above components, such as a packaging shell, an electrolyte, etc. The present application does not limit the above other necessary or optional components or materials, as long as a complete secondary battery can be obtained.

[0106] The second aspect of the present application provides an electronic device, which includes a secondary battery in any of the aforementioned embodiments. In the present application, the electronic device includes a handheld device, a vehicle-mounted device, a wearable device, etc. with an image processing function. Exemplarily, the electronic device may include, but is not limited to: a mobile phone, a tablet computer, a PDA, a laptop computer, a watch, etc. For example, the secondary battery of the present application is applied to electronic devices such as mobile phones, and the secondary battery has a longer cycle life, thereby extending the service life of the electronic device.

[0107] The third aspect of the present application provides a terminal device, which includes an electronic device in any of the aforementioned embodiments. In the present application, the terminal device may include but is not limited to mobile Internet devices, wearable devices, virtual reality devices, augmented reality devices, wireless terminals in industrial control, wireless terminals in unmanned driving, wireless terminals in remote surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, cellular phones, cordless phones, session initiation protocol phones, wireless local loop stations, personal digital assistants, handheld devices with wireless communication functions, computing devices, terminal devices in 5G networks, terminal devices in public land mobile communication networks, etc., and the implementation scheme of the present application is not limited to this.

[0108] Example

[0109] Hereinafter, the embodiments of the present application will be described in more detail with reference to Examples and Comparative Examples. Various tests and evaluations were performed according to the following methods.

[0110] Test methods and equipment:

[0111] Lithium deposition performance test:

[0112] The lithium-ion battery is charged and discharged cyclically and disassembled in a fully charged state to observe whether lithium is deposited in the area around the negative electrode tab. The number of cycles in which lithium deposition occurs in the area around the negative electrode tab is recorded as N, which is used to evaluate the lithium deposition performance of the lithium-ion battery. The more cycles, the less likely the lithium-ion battery is to deposit lithium; the fewer cycles, the more likely the lithium-ion battery is to deposit lithium. When the number of cycles N is 1000, if there is still no lithium deposition in the area around the negative electrode tab, it is recorded as "greater than 1000".

[0113] The lithium-ion battery is cyclically charged and discharged according to the following steps: at 25°C, the lithium-ion battery is charged to 4.35V at a constant current of 0.5C, then charged at a constant voltage of 4.35V until the current is less than 0.025C, left to stand for 5 minutes, and discharged to 3.0V at a constant current of 0.5C. This is one charge and discharge cycle.

[0114] The structure of the secondary battery of the present application can be applied to any secondary battery known in the art. It is understood that the following embodiments are only examples and do not limit the scope of protection of the present application. For example, the positive electrode collector, positive electrode active material, conductive agent, binder in the positive electrode sheet of the lithium-ion battery, the negative electrode collector, negative electrode active material, conductive agent, binder in the negative electrode sheet, and the components of the separator and electrolyte can all be made of materials or substances known in the art.

[0115] Example 1-1

[0116] <Preparation of positive electrode sheet>

[0117] The positive electrode active material lithium cobalt oxide, the conductive agent conductive carbon black, and the binder polyvinylidene fluoride are mixed in a mass ratio of 98:1:1, and N-methylpyrrolidone (NMP) is added as a solvent to prepare a slurry with a solid content of 75wt%, and the positive electrode slurry is obtained after vacuum stirring. The positive electrode slurry is evenly coated on one surface of a positive electrode current collector aluminum foil with a thickness of 10μm, and dried to obtain a positive electrode sheet with a single-sided positive electrode material layer coated with a coating thickness of 80μm. Then repeat the above steps on the other surface of the aluminum foil to obtain a positive electrode sheet with a double-sided positive electrode material layer. Cold press, then cut and weld the positive electrode tabs to obtain a positive electrode sheet with a specification of 74mm×867mm. Among them, the material of the positive electrode tab is aluminum with a thickness of 80μm.

[0118] Reference Figure 7The first negative electrode insulating tape and the second negative electrode insulating tape are pasted at the positions of the positive electrode material layer corresponding to the first negative electrode insulating tape and the second negative electrode insulating tape, and the first negative electrode insulating tape and the second negative electrode insulating tape are not embedded in the positive electrode material layer. The first negative electrode insulating tape and the second negative electrode insulating tape are both green glue, and the size of the first negative electrode insulating tape is 26mm×16mm×8μm (length×width×thickness), and the size of the second negative electrode insulating tape is 26μm×16mm×8mm (length×width×thickness).

[0119] <Preparation of negative electrode sheet> Thickness

[0120] The negative electrode active material artificial graphite, the thickener sodium carboxymethyl cellulose, and the binder styrene butadiene rubber are mixed in a mass ratio of 96:2:2, and deionized water is added as a solvent to prepare a slurry with a solid content of 50wt%. The negative electrode slurry is obtained after being stirred evenly by a vacuum mixer. The negative electrode slurry is evenly coated on one surface of a negative electrode current collector copper foil with a thickness of 10μm, and dried to obtain a negative electrode sheet with a single-sided negative electrode material layer coated with a coating thickness of 80μm. Then repeat the above steps on the other surface of the copper foil to obtain a negative electrode sheet with a double-sided negative electrode material layer coated. Cold press, then cut and weld the tabs to obtain a negative electrode sheet with a specification of 78mm×875mm for standby use. Among them, the material of the positive electrode tab is nickel and the thickness is 100μm.

[0121] Reference Figure 7 and Figure 8 At the positions of the negative electrode material layer corresponding to the third negative electrode insulating tape and the fourth negative electrode insulating tape, grooves are set by laser cleaning, and the third negative electrode insulating tape and the fourth negative electrode insulating tape are embedded in the negative electrode material layer. H3, W3, and W3 of the third negative electrode insulating tape embedded in the negative electrode material layer, and H4, W4, and W4 of the fourth negative electrode insulating tape embedded in the negative electrode material layer are shown in Table 1. The size of the third negative electrode insulating tape is 22mm×10mm×8μm (length×width×thickness), and the size of the fourth negative electrode insulating tape is 22mm×10mm×8μm (length×width×thickness). The third negative electrode insulating tape and the fourth negative electrode insulating tape are both green glue.

[0122] <Preparation of Electrolyte>

[0123] In a dry argon atmosphere glove box, ethylene carbonate (EC), propylene carbonate (PC), and diethyl carbonate (DEC) are mixed in a mass ratio of 1:1:1 to obtain an organic solvent, and then lithium salt LiPF6 is added to the organic solvent and mixed evenly to obtain an electrolyte. Among them, based on the mass of the electrolyte, the mass percentage of LiPF6 is 12.5%, and the rest is the organic solvent.

[0124] <Diaphragm>

[0125] A porous polypropylene film with a thickness of 7 μm was used as the separator.

[0126] <Preparation of lithium-ion batteries>

[0127] The positive electrode sheet, separator, and negative electrode sheet prepared above are stacked in order, so that the separator is located between the positive electrode sheet and the negative electrode sheet to play an isolating role, and the dielectric coating in the separator is adjacent to the negative electrode sheet, and the electrode assembly is wound. The electrode assembly is placed in an aluminum-plastic film packaging bag, and the moisture is removed at 80°C, and the prepared electrolyte is injected, and a lithium-ion battery is obtained through vacuum packaging, standing, formation, degassing, trimming and other processes.

[0128] Example 1-2 to Example 1-3

[0129] Except for adjusting the relevant preparation parameters according to Table 1, the rest is the same as Example 1-1. Among them, when the thickness, width and length of the third negative electrode insulating tape and the fourth negative electrode insulating tape embedded in the negative electrode material layer change, the thickness of the third negative electrode insulating tape and the fourth negative electrode insulating tape itself remains unchanged, and the width and length of the third negative electrode insulating tape and the fourth negative electrode insulating tape itself change accordingly, and are the same as the embedded width and length. In Example 1-3, the size of the first negative electrode insulating tape and the second negative electrode insulating tape is 40μm×16mm×8mm (length×width×thickness).

[0130] Examples 1-4

[0131] In <Preparation of Positive Electrode Sheet> and <Preparation of Negative Electrode Sheet>, in addition to the reference Figure 2 The first negative electrode insulating tape, the second negative electrode insulating tape, the third negative electrode insulating tape and the fourth negative electrode insulating tape are provided, and the relevant preparation parameters are adjusted according to Table 1, and the rest are the same as Example 1-1.

[0132] Among them, laser cleaning is used Figure 2 The positions of the positive electrode material layer corresponding to the first negative electrode insulating tape and the second negative electrode insulating tape are provided with grooves, the first negative electrode insulating tape and the second negative electrode insulating tape are embedded in the positive electrode material layer, and the third negative electrode insulating tape and the fourth negative electrode insulating tape are not embedded in the negative electrode material layer. H1, W1, W1 of the first negative electrode insulating tape embedded in the positive electrode material layer, and H2, W2, W2 of the second negative electrode insulating tape embedded in the positive electrode material layer are shown in Table 1.

[0133] Example 1-5 to Example 1-6

[0134] Except for adjusting the relevant preparation parameters according to Table 1, the rest is the same as Example 1-4. Among them, when the thickness, width and length of the first negative electrode insulating tape and the second negative electrode insulating tape embedded in the negative electrode material layer change, the thickness of the first negative electrode insulating tape and the second negative electrode insulating tape itself remains unchanged, and the width and length of the first negative electrode insulating tape and the second negative electrode insulating tape itself change accordingly, and are the same as the embedded width and length. In Example 1-6, the size of the third negative electrode insulating tape and the fourth negative electrode insulating tape is 32μm×10mm×8mm (length×width×thickness).

[0135] Examples 1-7

[0136] In <Preparation of Positive Electrode Sheet> and <Preparation of Negative Electrode Sheet>, in addition to the reference Fig.10 The first negative electrode insulating tape, the second negative electrode insulating tape, the third negative electrode insulating tape and the fourth negative electrode insulating tape are provided, and the relevant preparation parameters are adjusted according to Table 1, and the rest are the same as Example 1-1.

[0137] Among them, laser cleaning is used Fig.10 A groove is set at the position of the positive electrode material layer corresponding to the first negative electrode insulating tape and the second negative electrode insulating tape, and the first negative electrode insulating tape and the second negative electrode insulating tape are embedded in the positive electrode material layer; laser cleaning is adopted Fig.10 The positions of the negative electrode material layers corresponding to the third negative electrode insulating tape and the fourth negative electrode insulating tape are provided with grooves, and the third negative electrode insulating tape and the fourth negative electrode insulating tape are embedded in the negative electrode material layer. The first negative electrode insulating tape is embedded in H1, W1, W1 of the positive electrode material layer, the second negative electrode insulating tape is embedded in H2, W2, W2 of the positive electrode material layer, the third negative electrode insulating tape is embedded in H3, W3, W3 of the negative electrode material layer, and the fourth negative electrode insulating tape is embedded in H4, W4, W4 of the negative electrode material layer as shown in Table 1.

[0138] Example 1-8 to Example 1-10

[0139] Except for adjusting the relevant preparation parameters according to Table 1, the rest is the same as Example 1-7. Among them, when the thickness, width and length of the first negative electrode insulating tape and the second negative electrode insulating tape embedded in the negative electrode material layer change, the thickness of the first negative electrode insulating tape and the second negative electrode insulating tape itself remains unchanged, and the width and length of the first negative electrode insulating tape and the second negative electrode insulating tape itself change accordingly, and are the same as the embedded width and length. When the thickness, width and length of the third negative electrode insulating tape and the fourth negative electrode insulating tape embedded in the negative electrode material layer change, the thickness of the third negative electrode insulating tape and the fourth negative electrode insulating tape itself remains unchanged, and the width and length of the third negative electrode insulating tape and the fourth negative electrode insulating tape itself change accordingly, and are the same as the embedded width and length.

[0140] Example 2-1

[0141] In <Preparation of Positive Electrode Sheet> and <Preparation of Negative Electrode Sheet>, in addition to the reference Fig.11 The first positive electrode insulating tape, the second positive electrode insulating tape, the third positive electrode insulating tape and the fourth positive electrode insulating tape are provided, and the relevant preparation parameters are adjusted according to Table 2, and the rest is the same as Example 1-7.

[0142] Among them, laser cleaning is used Fig.11 A groove is set at the position of the negative electrode material layer corresponding to the first positive electrode insulating tape and the second positive electrode insulating tape, and the first positive electrode insulating tape and the second positive electrode insulating tape are embedded in the negative electrode material layer; laser cleaning is adopted Fig.11 The positions of the positive electrode material layers corresponding to the third positive electrode insulating tape and the fourth positive electrode insulating tape are provided with grooves, and the third positive electrode insulating tape and the fourth positive electrode insulating tape are embedded in the positive electrode material layer. The first positive electrode insulating tape, the second positive electrode insulating tape, the third positive electrode insulating tape and the fourth positive electrode insulating tape are all green glue, and the size of the first positive electrode insulating tape and the second positive electrode insulating tape is 26mm×16mm×8μm (length×width×thickness), and the size of the third positive electrode insulating tape and the fourth positive electrode insulating tape is 22μm×10mm×8mm (length×width×thickness).

[0143] Example 2-2 to Example 2-3

[0144] Except for adjusting the relevant preparation parameters according to Table 2, the rest is the same as Example 2-1.

[0145] Comparative Example 1

[0146] In <Preparation of Negative Electrode Sheet>, except that the groove is not provided in the negative electrode material layer, and the third negative electrode insulating tape and the fourth negative electrode insulating tape are directly pasted, the rest is the same as Example 1-1.

[0147] The preparation parameters and performance tests of various embodiments and comparative examples are shown in Tables 1 and 2.

[0148] Table 1

[0149]

[0150] Note: “ / ” in Table 1 indicates that there is no corresponding preparation parameter.

[0151] Referring to Table 1, it can be seen from Examples 1-1 to 1-10 and Comparative Example 1 that by setting the first negative electrode insulating tape, the second negative electrode insulating tape, the third negative electrode insulating tape and the fourth negative electrode insulating tape within the scope of the present application, the number of cycles of lithium deposition in the negative electrode tab area of ​​the obtained lithium ion battery is greater, indicating that the lithium deposition performance of the lithium ion battery is improved, so that the obtained lithium ion battery has a longer cycle life.

[0152] From Examples 1-1 to 1-10, the thickness, width, and length of the first negative electrode insulating tape, the second negative electrode insulating tape, the third negative electrode insulating tape, and the fourth negative electrode insulating tape embedded in the positive electrode material layer or the negative electrode material layer will affect the cycle performance and energy density of the lithium ion battery. When the above parameters are within the scope of the present application, the number of cycles of lithium deposition in the negative electrode tab region of the obtained lithium ion battery is relatively large, indicating that the lithium deposition performance of the lithium ion battery is improved, so that the obtained lithium ion battery has a longer life.

[0153] Table 2

[0154]

[0155] Note: “ / ” in Table 2 indicates that there is no corresponding preparation parameter.

[0156] Referring to Table 2, it can be seen from Examples 1-7 and 2-1 to 2-3 that, on the basis of setting the first negative electrode insulating tape, the second negative electrode insulating tape, the third negative electrode insulating tape and the fourth negative electrode insulating tape within the scope of the present application, the first positive electrode insulating tape, the second positive electrode insulating tape, the third positive electrode insulating tape and the fourth positive electrode insulating tape are also set within the scope of the present application, and the number of cycles in which lithium plating occurs in the negative electrode lug region of the lithium-ion battery is further increased, indicating that the lithium plating performance of the lithium-ion battery is improved, which is beneficial to further extend the cycle life of the lithium-ion battery.

[0157] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A secondary battery comprising a positive electrode sheet, a negative electrode sheet, a separator, a first negative electrode tab insulating adhesive tape, a second negative electrode tab insulating adhesive tape, a third negative electrode tab insulating adhesive tape and a fourth negative electrode tab insulating adhesive tape; The negative electrode plate comprises a negative electrode current collector and negative electrode material layers arranged on two surfaces of the negative electrode current collector, the negative electrode plate further comprises a negative electrode tab connected to the negative electrode current collector, and the area where the negative electrode current collector and the negative electrode tab are connected is the negative electrode tab area; The positive electrode sheet comprises a positive electrode current collector and a positive electrode material layer arranged on two surfaces of the positive electrode current collector; The first negative electrode tab insulating adhesive tape is arranged on the surface of the positive electrode material layer opposite to the negative electrode tab region, and the second negative electrode tab insulating adhesive tape is arranged on the surface of the positive electrode material layer opposite to the negative electrode tab region; The third negative electrode tab insulation tape is disposed on the surface of the negative electrode material layer on one surface of the negative electrode current collector and covers the negative electrode tab region, and the fourth negative electrode tab insulation tape is disposed on the surface of the negative electrode material layer on the other surface of the negative electrode current collector and is opposite to the third negative electrode tab insulation tape; Along the thickness direction of the secondary battery, the first negative electrode tab insulation tape and / or the second negative electrode tab insulation tape are at least partially embedded in the positive electrode material layer, and / or the third negative electrode tab insulation tape and / or the fourth negative electrode tab insulation tape are at least partially embedded in the negative electrode material layer.

2. The secondary battery according to claim 1, wherein The third negative electrode tab insulation tape and the fourth negative electrode tab insulation tape are at least partially embedded in the negative electrode material layer; Along the thickness direction of the secondary battery, the thickness H3 of the third negative electrode tab insulation glue embedded in the negative electrode material layer is 5μm to 10μm, and the thickness H4 of the fourth negative electrode tab insulation glue embedded in the negative electrode material layer is 5μm to 10μm; along the width direction of the secondary battery, the width W3 of the third negative electrode tab insulation glue embedded in the negative electrode material layer is 10mm to 16mm, and the width W4 of the fourth negative electrode tab insulation glue embedded in the negative electrode material layer is 10mm to 16mm; along the length direction of the secondary battery, the length L3 of the third negative electrode tab insulation glue embedded in the negative electrode material layer is 10mm to 40mm, and the length L4 of the fourth negative electrode tab insulation glue embedded in the negative electrode material layer is 10mm to 40mm.

3. The secondary battery according to claim 2, wherein: L3 is 20 mm to 30 mm, and / or L4 is 20 mm to 30 mm.

4. The secondary battery according to claim 1, wherein The first negative electrode tab insulation tape and the second negative electrode tab insulation tape are at least partially embedded in the positive electrode material layer; Along the thickness direction of the secondary battery, the thickness H1 of the first negative electrode tab insulation glue embedded in the positive electrode material layer is 5μm to 10μm, and the thickness H2 of the second negative electrode tab insulation glue embedded in the positive electrode material layer is 5μm to 10μm; along the width direction of the secondary battery, the width W1 of the first negative electrode tab insulation glue embedded in the positive electrode material layer is 10mm to 16mm, and the width W2 of the second negative electrode tab insulation glue embedded in the positive electrode material layer is 10mm to 16mm; along the length direction of the secondary battery, the length L1 of the first negative electrode tab insulation glue embedded in the positive electrode material layer is 10mm to 40mm, and the length L2 of the second negative electrode tab insulation glue embedded in the positive electrode material layer is 10mm to 40mm.

5. The secondary battery according to claim 4, wherein L1 is 20 mm to 30 mm, and / or L2 is 20 mm to 30 mm.

6. The secondary battery according to claim 1, wherein The first negative electrode tab insulation tape and the second negative electrode tab insulation tape are at least partially embedded in the positive electrode material layer, and the third negative electrode tab insulation tape and the fourth negative electrode tab insulation tape are at least partially embedded in the negative electrode material layer; Along the thickness direction of the secondary battery, the thickness H1 of the first negative electrode tab insulation glue embedded in the positive electrode material layer is 2.5μm to 5μm; the thickness H2 of the second negative electrode tab insulation glue embedded in the positive electrode material layer is 2.5μm to 5μm; the thickness H3 of the third negative electrode tab insulation glue embedded in the negative electrode material layer is 2.5μm to 5μm, and the thickness H4 of the fourth negative electrode tab insulation glue embedded in the negative electrode material layer is 2.5μm to 5μm; Along the width direction of the secondary battery, the width W1 of the first negative electrode tab insulation glue embedded in the positive electrode material layer is 10mm to 16mm, the width W2 of the second negative electrode tab insulation glue embedded in the positive electrode material layer is 10mm to 16mm, the width W3 of the third negative electrode tab insulation glue embedded in the negative electrode material layer is 8mm to 14mm, and the width W4 of the fourth negative electrode tab insulation glue embedded in the negative electrode material layer is 8mm to 14mm; Along the length direction of the secondary battery, the length L1 of the first negative electrode tab insulation glue embedded in the positive electrode material layer is 10mm to 40mm, the length L2 of the second negative electrode tab insulation glue embedded in the positive electrode material layer is 10mm to 40mm, the length L3 of the third negative electrode tab insulation glue embedded in the negative electrode material layer is 10mm to 40mm, and the length L4 of the fourth negative electrode tab insulation glue embedded in the negative electrode material layer is 10mm to 40mm.

7. The secondary battery according to claim 6, wherein The secondary battery satisfies at least one of the following characteristics: (1) L1 is 20 mm to 30 mm; (2) L2 is 20 mm to 30 mm; (3) L3 is 20 mm to 30 mm; (4) L4 is 20mm to 30mm.

8. The secondary battery according to claim 1, wherein The secondary battery further comprises a first positive electrode tab insulation tape, a second positive electrode tab insulation tape, a third positive electrode tab insulation tape and a fourth positive electrode tab insulation tape; The positive electrode sheet further includes a positive electrode tab connected to the positive electrode collector, and the area where the positive electrode collector is connected to the positive electrode tab is the positive electrode tab area; The first positive electrode tab insulating adhesive tape is arranged on the surface of the negative electrode material layer opposite to the positive electrode tab region, and the second positive electrode tab insulating adhesive tape is arranged on the surface of the negative electrode material layer opposite to the positive electrode tab region; the first positive electrode tab insulating adhesive tape and the second positive electrode tab insulating adhesive tape are at least partially embedded in the negative electrode material layer, The third positive electrode tab insulation tape is arranged on the surface of the positive electrode material layer on one surface of the positive electrode current collector and covers the positive electrode tab region, and the fourth positive electrode tab insulation tape is arranged on the surface of the positive electrode material layer on the other surface of the positive electrode current collector and is opposite to the third positive electrode tab insulation tape; the third positive electrode tab insulation tape and the fourth positive electrode tab insulation tape are at least partially embedded in the positive electrode material layer; Along the thickness direction of the secondary battery, the thickness of the first negative electrode tab insulation glue embedded in the positive electrode material layer is H1, the thickness of the second negative electrode tab insulation glue embedded in the positive electrode material layer is H2, the thickness of the third negative electrode tab insulation glue embedded in the negative electrode material layer is H3, and the thickness of the fourth negative electrode tab insulation glue embedded in the negative electrode material layer is H4; the thickness of the first positive electrode tab insulation glue embedded in the negative electrode material layer is H5, the thickness of the second positive electrode tab insulation glue embedded in the negative electrode material layer is H6, the thickness of the third positive electrode tab insulation glue embedded in the positive electrode material layer is H7, and the thickness of the fourth positive electrode tab insulation glue embedded in the positive electrode material layer is H8; the difference e between the thickness of the positive electrode tab and the negative electrode tab is 5μm to 20μm; (H1+H2+H3+H4)-(H5+H6+H7+H8)≤e / 2; Along the width direction of the secondary battery, the width W1 of the first negative electrode tab insulation glue embedded in the positive electrode material layer is 10mm to 16mm, the width W2 of the second negative electrode tab insulation glue embedded in the positive electrode material layer is 10mm to 16mm, the width W3 of the third negative electrode tab insulation glue embedded in the negative electrode material layer is 8mm to 14mm, and the width W4 of the fourth negative electrode tab insulation glue embedded in the negative electrode material layer is 8mm to 14mm; the width W5 of the first positive electrode tab insulation glue embedded in the negative electrode material layer is 10mm to 16mm, the width W6 of the second positive electrode tab insulation glue embedded in the negative electrode material layer is 10mm to 16mm, the width W7 of the third positive electrode tab insulation glue embedded in the positive electrode material layer is 8mm to 14mm, and the width W8 of the fourth positive electrode tab insulation glue embedded in the positive electrode material layer is 8mm to 14mm; Along the length direction of the secondary battery, the length L1 of the first negative electrode tab insulation glue embedded in the positive electrode material layer is 10mm to 40mm, the length L2 of the second negative electrode tab insulation glue embedded in the positive electrode material layer is 10mm to 40mm, the length L3 of the third negative electrode tab insulation glue embedded in the negative electrode material layer is 10mm to 40mm, and the length L4 of the fourth negative electrode tab insulation glue embedded in the negative electrode material layer is 10mm to 40mm; the length L5 of the first positive electrode tab insulation glue embedded in the negative electrode material layer is 10mm to 40mm, the length L6 of the second positive electrode tab insulation glue embedded in the negative electrode material layer is 10mm to 40mm, the length L7 of the third positive electrode tab insulation glue embedded in the positive electrode material layer is 10mm to 40mm, and the length L8 of the fourth positive electrode tab insulation glue embedded in the positive electrode material layer is 10mm to 40mm.

9. The secondary battery according to claim 8, wherein Along the thickness direction of the secondary battery, the secondary battery satisfies at least one of the following characteristics: (1) H1 is 2.5 μm to 10 μm; (2) H2 is 2.5 μm to 10 μm; (3) H3 is 2.5 μm to 10 μm; (4) H4: 2.5 μm to 10 μm; (5) H5 is 2 μm to 5 μm; (6) H6: 2 μm to 5 μm; (7) H7: 2 μm to 5 μm; (8) H8 is 2 μm to 5 μm.

10. The secondary battery according to claim 8, wherein The secondary battery satisfies at least one of the following characteristics: (1) L1 is 20 mm to 30 mm; (2) L2 is 20 mm to 30 mm; (3) L3 is 20 mm to 30 mm; (4) L4 is 20 mm to 30 mm; (5) L5 is 20 mm to 30 mm; (6) L6 is 20 mm to 30 mm; (7) L7 is 20 mm to 30 mm; (8) L8 is 20 mm to 30 mm. 11 . An electronic device comprising the secondary battery according to claim 1 .

12. A terminal device, comprising the electronic device according to claim 11.

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