Battery and battery module

Abstract

The utility model provides a battery and a battery module. The battery comprises a top cover, a first battery cell and a shell, the first battery cell is arranged in a closed space defined by the shell and the top cover; m negative electrode layers are formed in the direction perpendicular to the winding direction of the first battery cell and connected with the top cover through N negative electrode tabs, and N is larger than or equal to 2 and smaller than or equal to M; the bent part of the negative tab is in a C shape with a convex part facing the shell, and is arranged on the inner wall surface of the shell; the end part of the first connecting part of the negative electrode lug is connected with the top cover, and the end part of the second connecting part of the negative electrode lug is connected with each negative electrode layer; insulating layers are arranged on the second connecting parts of the n negative electrode tabs, and n is smaller than or equal to N. According to the battery, the risk of tab interpolation short circuit caused by the fact that negative tab redundancy is torn by an adhesive tape in the battery cell rebounding process is avoided, the defect of short circuit caused by gathering uncontrollable previous few layers of tab interpolation is overcome, the thickness of the insulating layer is controllable, the risk of thermal runaway of the battery is effectively reduced, and the safety performance of the battery is improved.

Description

Technical Field

[0001] The utility model relates to a battery and a battery module. Background Art

[0002] The tabs of existing batteries are generally led out from the end face of the winding structure. Among them, after the tabs are welded to the adapter, the tabs need to be bent inwards to improve space utilization and the energy density of the lithium-ion battery. Because the tabs are made of multiple layers of aluminum foil or copper foil, the distance from the root of the outer tab to the edge of the weld mark is short during ultrasonic welding, and the distance from the root of the tab to the edge of the weld mark is longer the further inward. After the tabs are bent, the area near the root of the inner tab is relatively loose, and the redundancy is uncontrollable after the tabs are folded. After the core is closed and put into the shell, the top cover exerts a certain pressure on the adapter and the tabs. The loose part near the root of the tabs is easily inserted into the winding core, and is connected to the positive and negative electrodes or foils, causing a short circuit. In addition, the smaller the space for bending the tabs after entering the shell, the greater the risk of tab insertion. Utility Model Content

[0003] The technical problem to be solved by the present invention is to provide a battery and battery module to overcome the defects in the prior art, such as the risk of battery short circuits caused by direct contact between the negative electrode tab and the positive electrode, or vice versa. This battery avoids the risk of tab short circuits caused by redundant tabs being torn by ultrasonic welding tape during the rebound of the battery cell, and overcomes the defects of tab short circuits caused by the scattered and uncontrollable tab contact at the tab ends. The thickness of the insulation layer provided on the tab is controllable, effectively reducing the risk of thermal runaway and improving the safety performance of the battery. The production process of the battery cell is simple to operate.

[0004] The utility model solves the above technical problems through the following technical solutions:

[0005] In a first aspect, the present invention provides a battery, characterized in that it includes a top cover, a first battery cell and a shell; each of the first battery cells is arranged in a closed space formed by the shell and the top cover;

[0006] The first battery cell is formed by winding a positive electrode sheet, a separator, and a negative electrode sheet stacked on each other, forming M negative electrode layers perpendicular to the winding direction of the first battery cell, and the negative electrode layers are connected to the top cover through N negative electrode tabs, 2≤N≤M;

[0007] Each of the negative electrode tabs comprises a first connecting portion, a bending portion, and a second connecting portion that are sequentially connected and integrally formed; wherein,

[0008] The bent portion is in a C-shape with a convex portion facing the shell, and is provided on the inner wall surface of the shell; an end portion of the first connecting portion is connected to the top cover, and an end portion of each second connecting portion is independently connected to each of the negative electrode layers;

[0009] An insulating layer is provided on the second connecting portions of n negative electrode tabs, n≤N; at least one negative electrode tab closest to the shell is provided with the insulating layer, and at least one negative electrode tab farthest from the shell is provided with the insulating layer.

[0010] In a second aspect, the present invention provides a battery comprising a top cover, second battery cells and a shell; each of the second battery cells is disposed in a closed space formed by the shell and the top cover;

[0011] The second battery cell is formed by winding a positive electrode sheet, a separator, and a negative electrode sheet stacked on each other, forming Y positive electrode layers perpendicular to the winding direction of the second battery cell, and the positive electrode layers are connected to the top cover through X positive electrode tabs, 2≤X≤Y;

[0012] Each of the positive electrode tabs comprises a first connecting portion, a bending portion, and a second connecting portion that are sequentially connected and integrally formed; wherein,

[0013] The bent portion is in a C-shape with a convex portion facing the shell, and is provided on the inner wall surface of the shell; an end portion of the first connecting portion is connected to the top cover, and an end portion of each second connecting portion is independently connected to each positive electrode layer;

[0014] An insulating layer is provided on the second connecting portions of x positive electrode tabs, x≤X; at least one positive electrode tab closest to the shell is provided with the insulating layer, and at least one positive electrode tab farthest from the shell is provided with the insulating layer.

[0015] In a third aspect, the present invention provides a battery module comprising the battery as described above.

[0016] The positive progress effect of this utility model is:

[0017] The battery avoids the risk of redundant tabs being torn by ultrasonic welding tape during the rebound of the battery cell, causing short circuits in the tabs. It overcomes the defects of the tab ends being relatively scattered and the first few layers of tabs being inserted and causing short circuits due to uncontrollable contraction. The thickness of the insulating layer on the tab is controllable, which effectively reduces the risk of thermal runaway of the battery and improves the safety performance of the battery. In addition, the production process of the battery cell is simple to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the battery structure of Example 1 of the present utility model;

[0019] Figure 2 Schematic diagram of the partial structure of the negative electrode tab in the battery of Example 1 of the present utility model;

[0020] Figure 3Schematic diagram of the unfolded negative electrode sheet in the battery of Embodiment 1 of the present utility model;

[0021] Figure 4 Schematic diagram of the processing of the insulating layer in the battery of Embodiment 1 of the present utility model;

[0022] Figure 5 Schematic diagram of the structure of the battery of Embodiment 3 of the present utility model.

[0023] Description of reference numerals:

[0024] Top cover 1

[0025] Connecting piece 2

[0026] Negative electrode tab 3

[0027] Three tabs 31 - 33 that are farthest from the housing and coated with an insulating layer

[0028] Three tabs 34 - 36 that are closest to the housing and coated with an insulating layer

[0029] Housing 4

[0030] First battery cell 5

[0031] Insulating layer 6

[0032] Negative electrode layer 7

[0033] Coating upper nozzle 81

[0034] Coating lower nozzle 82. Detailed implementation manners

[0035] The present utility model provides a battery, which includes a top cover, a first battery cell, and a housing; each of the first battery cells is disposed in a closed space formed by enclosing the housing and the top cover;

[0036] The first battery cell is wound by stacking a positive electrode sheet, a separator, and a negative electrode sheet, and M negative electrode layers are formed in a direction perpendicular to the winding direction of the first battery cell. The negative electrode layers are connected to the top cover through N negative electrode tabs, and 2 ≤ N ≤ M;

[0037] Each of the negative electrode tabs includes a first connecting portion, a bending portion, and a second connecting portion that are sequentially connected and integrally formed; wherein,

[0038] The bending portion is in a C shape with the convex portion facing the housing and is disposed on the inner wall surface of the housing; the end of the first connecting portion is connected to the top cover, and the ends of each of the second connecting portions are independently connected to each of the negative electrode layers;

[0039] An insulating layer is provided on the second connecting portions of n of the negative electrode tabs, where 2 ≤ n ≤ N; at least one negative electrode tab closest to the housing is provided with the insulating layer, and at least one negative electrode tab farthest from the housing is provided with the insulating layer.

[0040] In the present utility model, those skilled in the art should know that the first connecting portion, the bending portion, and the second connecting portion in each of the negative electrode tabs are of an integral structure; the negative electrode tab is divided into the above three parts to illustrate the bending structure and its connection relationship of the negative electrode tab.

[0041] In the present utility model, those skilled in the art should know that the separator further includes a first separator and a second separator. The first separator is disposed between the positive electrode plate and the negative electrode plate, and the second separator is disposed on the other side of the positive electrode plate or the other side of the negative electrode plate; through winding, a structure of a first separator layer, a positive electrode layer, a second separator layer, and a negative electrode layer is formed.

[0042] In the present utility model, those skilled in the art should know that the first battery cell is vertically disposed inside the housing, with the cross-sections of the positive electrode layer and the negative electrode layer facing upward, so as to be connected to the cover plate through the tabs.

[0043] In some embodiments, an insulating layer is provided on one side of the second connecting portion.

[0044] In a specific embodiment, when an insulating layer is provided on one side of the second connecting portion, the insulating layer is disposed on the surface of the second connecting portion close to the housing side, or the insulating layer is disposed on the surface of the second connecting portion far from the housing side.

[0045] In some embodiments, insulating layers are provided on both sides of the second connecting portion.

[0046] In a specific embodiment, the number of the negative electrode layers is N - 100, for example, 2N.

[0047] In some embodiments, the number N of the negative electrode tabs is 20 - 60; the number of the tabs can be determined according to the negative electrode layer in the battery cell.

[0048] In a specific embodiment, the number N of the negative electrode tabs is 20 - 50, for example, 22, 40, 47, or 48.

[0049] In some embodiments, each of the negative electrode tabs converges at the positions of the first connecting portion and the bending portion to form a negative electrode tab bundle.

[0050] In some embodiments, the number n of the negative electrode tabs provided with the insulating layer is 3 - N.

[0051] In one embodiment, "the number n of the negative electrode tabs provided with the insulating layer is N" means that each negative electrode tab is coated with the insulating layer.

[0052] In some embodiments, at least 3 negative electrode tabs closest to the housing are provided with the insulating layer; at least 3 negative electrode tabs farthest from the housing are provided with the insulating layer; the tabs farthest from the housing are prone to the defect of internal insertion resulting in short circuit. By arranging the insulating layer in the above manner, the situation of internal insertion of multiple tabs can be effectively prevented.

[0053] In a specific embodiment, 3 negative electrode tabs closest to the housing are provided with the insulating layer; 3 negative electrode tabs farthest from the housing are provided with the insulating layer.

[0054] In a specific embodiment, 5 negative electrode tabs closest to the housing are provided with the insulating layer; 5 negative electrode tabs farthest from the housing are provided with the insulating layer.

[0055] In some embodiments, the battery further includes a connecting piece, which is arranged on the inner surface of the top cover and connected to the first connecting parts of the respective tabs.

[0056] In some embodiments, the total coating thickness of the insulating layer on the second connecting parts of the respective negative electrode tabs is 0 to 1 / 3 of the total thickness of the respective negative electrode layers, but not 0; wherein, the total coating thickness of the insulating layer on the second connecting parts of the respective negative electrode tabs refers to the sum of the thicknesses of the insulating layers on each negative electrode tab coated with the insulating layer; the total thickness of the respective negative electrode layers refers to the sum of the thicknesses of each negative electrode layer on the axial cross-section of the first battery cell.

[0057] In the present utility model, the height of the insulating layer is generally lower than the lower boundary of the ultrasonic welding mark; the lower boundary of the ultrasonic welding mark can be located at the junction of the second connecting part and the bending part.

[0058] In some embodiments, the single-sided coating height of the insulating layer is 2 - 8 mm; the single-sided coating height of the insulating layer refers to the vertical distance between the coated end of the insulating layer and the battery cell.

[0059] In a specific embodiment, the single-sided coating height of the insulating layer is 2 - 7.5 mm; preferably 2 - 3 mm or 5 - 7.5 mm, such as 2 mm, 3 mm, 5 mm or 7.5 mm.

[0060] In some embodiments, the material of the insulating layer is polyurethane, silane, boehmite, polyethylene, polyvinyl chloride, epoxy resin, alumina or magnesia.

[0061] The present utility model provides a battery, which includes a top cover, a second battery cell, and a housing; each of the second battery cells is disposed in a closed space formed by enclosing the housing and the top cover;

[0062] The second battery cell is formed by winding a positive electrode sheet, a separator, and a negative electrode sheet stacked on each other. Y positive electrode layers are formed in a direction perpendicular to the winding direction of the second battery cell. The positive electrode layers are connected to the top cover through X positive electrode tabs, where 2 ≤ X ≤ Y;

[0063] Each of the positive electrode tabs includes a first connection portion, a bent portion, and a second connection portion that are sequentially connected and integrally formed; wherein,

[0064] The bent portion is in a C shape with the convex portion facing the housing and is disposed on the inner wall surface of the housing; the end of the first connection portion is connected to the top cover, and the ends of each of the second connection portions are independently connected to each of the positive electrode layers;

[0065] Insulating layers are provided on the second connection portions of x positive electrode tabs, where x ≤ X; at least one positive electrode tab closest to the housing is provided with an insulating layer, and at least one positive electrode tab farthest from the housing is provided with an insulating layer.

[0066] In the present utility model, those skilled in the art should know that the first connection portion, the bent portion, and the second connection portion in each of the positive electrode tabs are of an integral structure; dividing the positive electrode tab into these three parts is used to illustrate the bent structure and connection relationship of the positive electrode tab.

[0067] In the present utility model, those skilled in the art should know that the separator further includes a first separator and a second separator. The first separator is disposed between the positive electrode sheet and the negative electrode sheet, and the second separator is disposed on the other side of the positive electrode sheet or the other side of the negative electrode sheet. Through winding, a structure of a first separator layer, a positive electrode layer, a second separator layer, and a negative electrode layer is formed.

[0068] In some embodiments, the number X of the positive electrode tabs is 20 - 60.

[0069] In a specific embodiment, the number X of the positive electrode tabs is 20 - 50, for example, 22, 40, 47, or 48.

[0070] In some embodiments, each of the positive electrode tabs converges at the positions of the first connection portion and the bent portion to form a positive electrode tab bundle.

[0071] In some embodiments, the number x of the positive electrode tabs provided with the insulating layer is 3 - X.

[0072] In a certain embodiment, "the number x of the positive electrode tabs provided with the insulating layer is X" means that each positive electrode tab is coated with an insulating layer.

[0073] In some embodiments, at least three positive electrode tabs closest to the housing are provided with the insulating layer; at least three positive electrode tabs farthest from the housing are provided with the insulating layer; the tabs farthest from the housing are prone to the defect of internal insertion resulting in short circuit. By arranging the insulating layer in the above manner, the effect of preventing the internal insertion of the tabs can be effectively improved.

[0074] In a specific embodiment, three positive electrode tabs closest to the housing are provided with the insulating layer; three positive electrode tabs farthest from the housing are provided with the insulating layer.

[0075] In a specific embodiment, five positive electrode tabs closest to the housing are provided with the insulating layer; five positive electrode tabs farthest from the housing are provided with the insulating layer.

[0076] In some embodiments, one side of the second connecting portion is provided with an insulating layer, or both sides of the second connecting portion are provided with insulating layers.

[0077] In some embodiments, the number of the positive electrode layers is X - 100, for example, 2X.

[0078] In some embodiments, the total coating thickness of the insulating layer on the second connecting portion of each positive electrode tab is 0 to 1 / 3 of the total thickness of each positive electrode layer, but not 0; wherein, the total coating thickness of the insulating layer on the second connecting portion of each positive electrode tab refers to the sum of the thicknesses of the insulating layer on each positive electrode tab coated with the insulating layer; the total thickness of each positive electrode layer refers to the sum of the thicknesses of each positive electrode layer on the axial cross-section of the second battery cell.

[0079] In some embodiments, the single-sided coating height of the insulating layer is 2 - 8 mm; the single-sided coating height of the insulating layer refers to the vertical distance between the coated end of the insulating layer and the battery cell.

[0080] In a specific embodiment, the single-sided coating height of the insulating layer is 2 - 7.5 mm; preferably 2 - 3 mm or 5 - 7.5 mm, for example, 2 mm, 3 mm, 5 mm or 7.5 mm.

[0081] In some embodiments, the material of the insulating layer is polyurethane, silane, boehmite, polyethylene, polyvinyl chloride, epoxy resin, alumina or magnesia.

[0082] The present utility model provides a battery module, which includes the battery as described above.

[0083] The following are some preferred embodiments, and the present utility model will be described more clearly and completely in conjunction with the accompanying drawings.

[0084] Embodiment 1

[0085] This embodiment discloses a lithium-ion battery. Figure 1 It is a schematic structural diagram of the battery in this embodiment; Figure 2 It is a partial structural diagram of the negative electrode tab in the battery of this embodiment; Figure 3 It is an unfolded schematic diagram of the negative electrode sheet in the battery of this embodiment.

[0086] The lithium-ion battery includes a top cover 1, a connecting piece 2, a first battery cell 5, and a housing 4; each first battery cell 5 is arranged in a closed space formed by enclosing the housing 4 and the top cover 1;

[0087] The first battery cell 5 is wound by stacking a positive electrode sheet, a separator, and a negative electrode sheet. 20 negative electrode layers 7 are formed in a direction perpendicular to the winding direction of the first battery cell 5. The negative electrode layers 7 are connected to the top cover 1 through 10 negative electrode tabs 3; the connecting piece 2 is arranged on the inner surface of the top cover 1;

[0088] Each negative electrode tab 3 includes a first connecting portion, a bending portion, and a second connecting portion that are sequentially connected and integrally formed; wherein,

[0089] The bending portion is in a C shape with the convex portion facing the housing 4 and is arranged at the inner wall surface of the housing 4; the end of the first connecting portion is connected to the top cover 1, and the ends of each second connecting portion are independently connected to each negative electrode layer 7;

[0090] The 3 negative electrode tabs 3 closest to the housing 4 are provided with an insulating layer 6, that is, the 3 tabs 34 - 36 closest to the housing 4 and coated with the insulating layer 6; the 3 negative electrode tabs 3 farthest from the housing 4 are provided with an insulating layer 6, that is, the 3 tabs 31 - 33 farthest from the housing 4 and coated with the insulating layer 6.

[0091] The two sides of the second connecting portion are sprayed with an insulating material to form the insulating layer 6. The material of the insulating layer is polyurethane; each negative electrode tab 3 converges at the positions of the first connecting portion and the bending portion to form a negative electrode tab bundle.

[0092] Figure 4 It is a processing schematic diagram of the insulating layer in the battery of this embodiment; the end of the negative electrode tab 3 is sprayed by a coating upper nozzle 81 and a coating lower nozzle 82 to form the insulating layer 6; the total coating thickness of the insulating layer 6 on the second connecting portion of each negative electrode tab 3 is 1 / 3 of the total thickness of each negative electrode layer 7; the single-sided coating height of the insulating layer 6 is 5 mm.

[0093] In this embodiment, whether the first tab is pulled up by the ultrasonic welding tape during the battery cell rebound and then inserted into the core after core combination, or the first 3 layers of tabs with uncontrollable tab convergence are inserted into the core, it will not cause a short circuit in the battery cell, effectively improving the production yield and ensuring the safety performance of the battery cell.

[0094] Embodiment 2

[0095] This embodiment discloses a lithium-ion battery; the structure of this battery is similar to that of Embodiment 1.

[0096] The lithium-ion battery includes a top cover, a connecting piece, a second battery cell, and a housing; each second battery cell is disposed in a closed space formed by enclosing the housing and the top cover;

[0097] The second battery cell is formed by winding a positive electrode sheet, a separator, and a negative electrode sheet stacked on each other, and 20 positive electrode layers are formed in a direction perpendicular to the winding direction of the second battery cell. The positive electrode layers are connected to the top cover through 10 positive electrode tabs; the connecting piece is disposed on the inner surface of the top cover;

[0098] Each tab includes a first connecting portion, a bending portion, and a second connecting portion that are sequentially connected and integrally formed; wherein,

[0099] The bending portion is in a C shape with the convex portion facing the housing and is disposed at the inner wall surface of the housing; the end of the first connecting portion is connected to the top cover, and the ends of each second connecting portion are independently connected to each positive electrode layer;

[0100] Insulating layers are provided on the 3 positive electrode tabs closest to the housing; insulating layers are provided on the 3 positive electrode tabs farthest from the housing.

[0101] The double sides of the second connecting portion are sprayed with an insulating material to form an insulating layer, and the material of the insulating layer is polyurethane; each positive electrode tab converges at the positions of the first connecting portion and the bending portion to form a positive electrode tab bundle.

[0102] The total coating thickness of the insulating layer on the second connecting portion of each positive electrode tab is 1 / 3 of the total thickness of each positive electrode layer; the single-sided coating height of the insulating layer is 5 mm.

[0103] In this embodiment, whether the first tab is pulled up by the ultrasonic welding tape during the rebound of the battery cell and then inserted into the core after the cores are combined, or the first 3 layers of tabs with uncontrollable tab convergence are inserted into the core, it will not cause a short circuit of the battery cell, effectively improving the yield rate of mass production and ensuring the safety performance of the battery cell.

[0104] Embodiment 3

[0105] This embodiment discloses a lithium-ion battery. Figure 5 It is a schematic structural diagram of the battery of this embodiment.

[0106] The lithium-ion battery includes a top cover, a housing, a first battery cell as in Embodiment 1, and a second battery cell as in Embodiment 2; the first battery cell and the second battery cell are symmetrically arranged along the central axis of the battery in a closed space formed by enclosing the top cover and the housing.

[0107] Such as Figure 5As shown, cross-section B is the cross-section of the battery cell at the negative electrode, and its specific structure is as in Embodiment 1. Cross-section A is the cross-section of the battery cell at the positive electrode, and its specific structure is as in Embodiment 2.

[0108] In this embodiment, whether the first tab is pulled up by the ultrasonic welding tape during the rebound of the battery cell and then inserted into the core after core combination, or the first three layers of tabs with uncontrollable tab convergence are inserted into the core, it will not cause a short circuit in the battery cell, effectively improving the yield of mass production and ensuring the safety performance of the battery cell.

[0109] It can be seen from the embodiments of the present application that the battery of the present utility model can avoid the risk of short circuit caused by the tearing of the negative tab redundancy by the ultrasonic welding tape during the rebound of the battery cell, overcome the defect of short circuit caused by the scattered connection at the end of the tab and the insertion of the first few layers of tabs with uncontrollable convergence, and the thickness of the insulating layer provided on the tab is controllable, effectively reducing the risk of causing thermal runaway of the battery and improving the safety performance of the battery; and the production process of this battery cell is simple to operate.

Claims

1. A battery, characterized in that, It includes a top cover, a first battery cell, and a housing; each of the first battery cells is disposed in a closed space formed by enclosing the housing and the top cover; The first battery cell is formed by winding a positive electrode sheet, a separator, and a negative electrode sheet stacked on each other, and M negative electrode layers are formed in a direction perpendicular to the winding direction of the first battery cell. The negative electrode layers are connected to the top cover through N negative electrode tabs, where 2 ≤ N ≤ M; Each of the negative electrode tabs includes a first connection portion, a bent portion, and a second connection portion that are sequentially connected and integrally formed; where The bent portion is in a C shape with the convex portion facing the housing and is disposed at the inner wall surface of the housing; the end of the first connection portion is connected to the top cover, and the ends of each of the second connection portions are independently connected to each of the negative electrode layers; An insulating layer is provided on the second connection portions of n negative electrode tabs, where 2 ≤ n ≤ N; at least 1 negative electrode tab closest to the housing is provided with the insulating layer, and at least 1 negative electrode tab farthest from the housing is provided with the insulating layer.

2. The battery according to claim 1, characterized in that, The insulating layer is provided on one side of the second connection portion; Or, the insulating layer is provided on both sides of the second connection portion; Or, the number of the negative electrode layers is N - 100.

3. The battery according to claim 1, characterized in that, The negative electrode tabs satisfy one or more of the following conditions: ① The number N of the negative electrode tabs is 20 - 60; ② Each of the negative electrode tabs converges at the positions of the first connection portion and the bent portion to form a negative electrode tab bundle; ③ The number n of the negative electrode tabs provided with the insulating layer is 3 - N; ④ At least 3 negative electrode tabs closest to the housing are provided with the insulating layer; at least 3 negative electrode tabs farthest from the housing are provided with the insulating layer.

4. The battery according to claim 1, wherein, The battery further includes a connecting piece, which is disposed on the inner surface of the top cover and is connected to the first connection portions of each of the negative electrode tabs.

5. The battery according to claim 1, characterized in that, The insulating layer satisfies one or more of the following conditions: ① The total coating thickness of the insulating layer on the second connection portions of each of the negative electrode tabs is 0 to 1 / 3 of the total thickness of each of the negative electrode layers, but not 0; ② The single-sided coating height of the insulating layer is 2 - 8 mm; ③ The material of the insulating layer is polyurethane, silane, boehmite, polyethylene, polyvinyl chloride, epoxy resin, alumina, or magnesia.

6. A battery, characterized in that, It includes a top cover, a second battery cell, and a housing; each of the second battery cells is disposed in a closed space formed by enclosing the housing and the top cover; The second battery cell is formed by winding a positive electrode sheet, a separator, and a negative electrode sheet stacked on each other, and Y positive electrode layers are formed in a direction perpendicular to the winding direction of the second battery cell. The positive electrode layers are connected to the top cover through X positive electrode tabs, where 2 ≤ X ≤ Y; Each of the positive electrode tabs includes a first connection portion, a bent portion, and a second connection portion that are sequentially connected and integrally formed; where The bent portion is in a C shape with the convex portion facing the housing and is disposed at the inner wall surface of the housing; the end of the first connection portion is connected to the top cover, and the ends of each of the second connection portions are independently connected to each of the positive electrode layers; An insulating layer is provided on the second connecting portion of x of the positive electrode tabs, where x ≤ X; at least one positive electrode tab closest to the housing is provided with the insulating layer, and at least one positive electrode tab farthest from the housing is provided with the insulating layer.

7. The battery according to claim 6, wherein, The positive electrode tab satisfies one or more of the following conditions: ① The number X of the positive electrode tabs is 20 - 60; ② Each of the positive electrode tabs converges at the positions of the first connecting portion and the bent portion to form a positive electrode tab bundle; ③ The number x of the positive electrode tabs provided with the insulating layer is 3 - X; ④ At least 3 positive electrode tabs closest to the housing are provided with the insulating layer; at least 3 positive electrode tabs farthest from the housing are provided with the insulating layer.

8. The battery according to claim 6, characterized in that, The battery satisfies one or more of the following conditions: ① The insulating layer is provided on one side of the second connecting portion, or, the insulating layer is provided on both sides of the second connecting portion; ② The number of the positive electrode layers is X - 100; ③ The total coating thickness of the insulating layer on the second connecting portion of each positive electrode tab is 0 to 1 / 3 of the total thickness of each positive electrode layer, but not 0; ④ The single-sided coating height of the insulating layer is 2 - 8 mm; ⑤ The material of the insulating layer is polyurethane, silane, boehmite, polyethylene, polyvinyl chloride, epoxy resin, alumina or magnesia.

9. A battery module, characterized in that, It includes the battery according to any one of claims 1 - 5 or the battery according to any one of claims 6 - 8.

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