Pole piece, secondary battery and electric equipment

Abstract

The invention discloses a pole piece, a secondary battery and electric equipment, the pole piece comprises a current collector, the current collector is provided with a plurality of first slot positions and a plurality of second slot positions on one side of the current collector in the width direction, each first slot position is provided with a tab or two tabs arranged at intervals, and the second slot position is not provided with tabs. And in the length direction of the current collector, an odd number of second slots are arranged between every two adjacent first slots. The tab is arranged in the first slot position, so that when the pole piece participates in winding to form the electrode assembly of the secondary battery, the space occupied by the tab along the extending direction can be reduced, and the energy density of the secondary battery can be improved. An odd number of second slot positions are arranged between every two adjacent first slot positions, and the first slot positions and the second slot positions are located on the bending sections on the different sides of the winding structure respectively, so that the possibility that the first slot positions and the second slot positions interfere with each other along the thickness of the electrode assembly can be reduced; and the possibility of interference of tabs with different polarities along the thickness of the electrode assembly can be reduced.

Description

Technical Field

[0001] This application relates to the technical field of energy storage, and particularly to an electrode sheet, a secondary battery, and an electrical device. Background Art

[0002] Current secondary batteries include a housing and an electrode assembly disposed within the housing. Among them, the electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a separator that separates the positive electrode sheet from the negative electrode sheet. According to the stacking method and manufacturing process of the positive electrode sheet, negative electrode sheet, and separator, the electrode assembly can be divided into a stacked electrode assembly and a wound electrode assembly. Generally speaking, the polarities of both the stacked electrode assembly and the wound electrode assembly are led out through tabs. Summary of the Invention

[0003] Regarding the secondary batteries in the prior art, the inventors have found that currently, the positive tab is electrically connected to the positive electrode sheet and extends out of the edge of the positive electrode sheet, and the negative tab is electrically connected to the negative electrode sheet and extends out of the edge of the negative electrode sheet. The extended positive tab and negative tab will additionally occupy a certain amount of space, resulting in an increase in the size of the secondary battery in the extending direction of the tabs (i.e., the length direction or width direction of the secondary battery). Thus, the energy density of the secondary batteries in the prior art needs to be improved.

[0004] In view of the above situation, it is necessary to provide an electrode sheet that is conducive to improving the energy density of the secondary battery.

[0005] The first aspect of this application provides an electrode sheet, including a current collector. On one side in the width direction of the current collector, the current collector is provided with a plurality of first slots and a plurality of second slots. Each first slot is provided with one tab or two spaced-apart tabs, and no tab is provided in the second slot. Along the length direction of the current collector, an odd number of second slots are provided between two adjacent first slots.

[0006] The tabs are disposed in the first slots. When the electrode sheet participates in winding to form the electrode assembly of the secondary battery, it can reduce the space required for the tabs to extend along their extending direction, which is conducive to improving the energy density of the secondary battery. Moreover, along the length direction of the current collector, an odd number of second slots are provided between two adjacent first slots. When the electrode sheet participates in winding to form the electrode assembly of the secondary battery, by making the first slots and the second slots located on different side bends of the winding structure respectively, it can reduce the possibility of interference between the first slots and the second slots along the thickness of the electrode assembly, which is conducive to reducing the possibility of interference between the tabs of different polarities along the thickness of the electrode assembly.

[0007] In one or more of the above embodiments, each first slot is provided with two spaced-apart tabs, and the first slots and the second slots are alternately arranged. When the electrode sheet participates in winding to form the electrode assembly of the secondary battery, it can facilitate the arrangement of tabs in each winding layer.

[0008] In one or more of the above embodiments, on one side in the width direction of the current collector, a third slot is provided in the current collector, and a tab is provided in the third slot. Along the length direction of the current collector, the third slot is provided at the end of the current collector, and an odd number of second slots are provided between the third slot and the adjacent first slot. When the electrode sheet participates in winding to form the electrode assembly of the secondary battery, the third slot can be located at the winding starting end. Along the winding direction of the electrode sheet, it is beneficial for the electrode sheet to make full use of the space of the innermost winding layer, thereby being beneficial to further improving the energy density of the secondary battery.

[0009] In one or more of the above embodiments, from one end to the other end along the length direction of the current collector, the distance between two tabs in a plurality of first slots increases. When the electrode sheet participates in winding to form the electrode assembly of the secondary battery, as the number of winding layers increases, the bending section of the winding structure needs to have a larger arc length. From one end to the other end along the length direction of the current collector, by increasing the distance between two tabs in a plurality of first slots, it is possible to facilitate the alignment of a plurality of tabs of the same polarity located in different winding layers along the thickness direction of the electrode assembly, which is beneficial to reducing the space required for the tabs to occupy along their width direction, thereby being beneficial to further improving the energy density of the secondary battery.

[0010] In one or more of the above embodiments, from one end to the other end along the length direction of the current collector, the slot widths of a plurality of first slots increase, and the slot widths of a plurality of second slots increase. It is possible to reduce the space required for the first slots and the second slots to occupy along the length direction of the electrode sheet. When the electrode sheet participates in winding to form the electrode assembly of the secondary battery, it is possible to facilitate the alignment of a plurality of first slots and a plurality of second slots located in different winding layers along the thickness direction of the electrode assembly respectively, which is beneficial to reducing the space required for the first slots and the second slots to occupy along the width direction of the tabs, thereby being beneficial to further improving the energy density of the secondary battery.

[0011] In one or more of the above embodiments, along the length direction of the current collector, the slot width of the first slot is W1, the slot width of the second slot is W2, and 5 mm ≤ W1 ≤ 40 mm, 5 mm ≤ W2 ≤ 40 mm.

[0012] In one or more of the above embodiments, along the width direction of the current collector, the slot depths of a plurality of first slots are equal, the slot depths of a plurality of second slots are equal, the slot depth of the first slot is H1, the slot depth of the second slot is H2, and 1 mm ≤ H1 ≤ 15 mm, 1 mm ≤ H2 ≤ 15 mm.

[0013] In one or more of the above embodiments, the tab and the current collector are integrally formed. When machining the first slot on the current collector, the tab can also be machined incidentally, which is beneficial to improving the convenience of manufacturing the electrode sheet.

[0014] In one or more of the above embodiments, the electrode tab is a positive electrode tab according to its polarity, and the electrode lug is a positive electrode lug according to its polarity. The electrode tab further includes an insulating member that covers a part of the surface of the positive electrode tab and a part of the surface of the positive electrode lug. When the positive electrode tab participates in winding to form an electrode assembly of a secondary battery, it is beneficial to reduce the risk of short circuit caused by the burrs on the edge of the negative electrode tab contacting the positive electrode tab or the positive electrode lug.

[0015] In one or more of the above embodiments, the current collector includes a protruding portion disposed between the first slot and the adjacent second slot, and the surface of the protruding portion is coated with an active material. When the electrode tab participates in winding to form an electrode assembly of a secondary battery, it is beneficial to improve the energy density of the secondary battery.

[0016] The second aspect of the present application provides a secondary battery, including a housing and an electrode assembly, and the electrode assembly is received in the housing. The electrode assembly includes the electrode tab described in the first aspect of the present application. The electrode tabs are divided into positive electrode tabs and negative electrode tabs according to different polarities, and the electrode lugs are divided into positive electrode lugs and negative electrode lugs according to different polarities. The first slot of the positive electrode tab is defined as the first positive slot, the second slot of the positive electrode tab is defined as the second positive slot, the first slot of the negative electrode tab is defined as the first negative slot, and the second slot of the negative electrode tab is defined as the second negative slot. Two positive electrode lugs are provided in the first positive slot, no positive electrode lug is provided in the second positive slot, two negative electrode lugs are provided in the first negative slot, and no negative electrode lug is provided in the second negative slot. When observing along the first direction, the electrode assembly has a first notch portion and a second notch portion. A plurality of first positive slots and a plurality of second negative slots are disposed in the first notch portion, a plurality of first negative slots and a plurality of second positive slots are disposed in the second notch portion, a plurality of positive electrode lugs are led out from the first notch portion, and a plurality of negative electrode lugs are led out from the second notch portion. The first direction is the thickness direction of the electrode assembly.

[0017] By disposing a plurality of first positive slots and a plurality of second negative slots in the first notch portion, and a plurality of first negative slots and a plurality of second positive slots in the second notch portion, it is possible to arrange the positive electrode lugs in the first positive slot in the first notch portion and the negative electrode lugs in the first negative slot in the second notch portion, thereby reducing the space required for the electrode lugs along their extending direction and being beneficial to improving the energy density of the secondary battery.

[0018] In one or more of the above embodiments, the electrode assembly includes a separator that separates the positive electrode tab and the negative electrode tab. After the positive electrode tab, the negative electrode tab, and the separator are stacked, they are wound to form a wound structure.

[0019] In one or more of the above embodiments, along the first direction, a plurality of positive tabs are gathered to form a first tab bundle, a plurality of negative tabs are gathered to form a second tab bundle, the first tab bundle is accommodated in the first notch, and the second tab bundle is accommodated in the second notch. This can facilitate the first tab bundle not exceeding the first notch along the extension direction of the positive tab, and the second tab bundle not exceeding the second notch along the extension direction of the negative tab, which is conducive to further improving the energy density of the secondary battery.

[0020] In one or more of the above embodiments, the secondary battery includes a first adapter and a second adapter, the first adapter is connected to the first tab bundle and extends out of the shell, and the second adapter is connected to the second tab bundle and extends out of the shell. When the first tab bundle is accommodated in the first notch portion and the second tab bundle is accommodated in the second notch portion, the polarity of the electrode assembly can be easily drawn out through the first adapter and the second adapter.

[0021] In one or more of the above embodiments, the first notch portion and the second notch portion are respectively located at different corners of the electrode assembly. The shell is a flexible packaging bag, and the shell includes a first shell and a second shell. Along the first direction, the first shell and the second shell are arranged opposite to each other and heat-sealed, and a sealing edge portion is formed at the connection between the first shell and the second shell. The sealing edge portion includes a first side seal portion, a second side seal portion and a top seal portion. When viewed along the second direction, the first adapter and the second adapter are located between the first side seal portion and the second side seal portion, and the top seal portion is located between the first adapter and the second adapter. The second direction is the extension direction of the electrode ear. The first side seal portion, the second side seal portion and the top seal portion are bent toward the peripheral wall of the electrode assembly. By locating the first notch portion and the second notch portion at different corners of the electrode assembly, respectively, the first adapter and the second adapter can be conveniently disposed at different corners of the shell, respectively, which is beneficial to reducing the possibility of interference between the first side seal portion, the second side seal portion and the top seal portion when they are each bent toward the peripheral wall of the electrode assembly, and reducing the possibility of interference between the first adapter and the second adapter portion when the top seal portion is bent toward the peripheral wall of the electrode assembly, thereby helping to reduce the possibility of loss of energy density of the secondary battery due to the protrusion of the top seal portion.

[0022] In one or more of the above embodiments, along the first direction, the projection of the first negative slot is located within the projection range of the second positive slot, and the projection of the second negative slot is located within the projection range of the first positive slot. Along the direction perpendicular to the first direction, the negative electrode sheet can be easily extended beyond the positive electrode sheet, which is beneficial to reduce the risk of lithium deposition in the secondary battery.

[0023] The third aspect of the present application provides an electric device, comprising the secondary battery described in the second aspect of the present application. By increasing the energy density of the secondary battery, it is beneficial to improve the endurance of the electric device. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1Schematic diagram of the structure of the electrode sheet provided in the first embodiment of the present application.

[0025] Figure 2 Schematic diagram of the structure of the electrode sheet provided in the second embodiment of the present application.

[0026] Figure 3 Schematic diagram of the structure of the electrode sheet provided in the third embodiment of the present application.

[0027] Figure 4 Schematic diagram of the structure of the electrode sheet provided in the fourth embodiment of the present application.

[0028] Figure 5 Schematic diagram of the structure of the electrode sheet provided in the fifth embodiment of the present application.

[0029] Figure 6 Schematic diagram of the winding of the positive electrode sheet and the negative electrode sheet provided in one embodiment of the present application.

[0030] Figure 7 Schematic diagram of the secondary battery provided in one embodiment of the present application.

[0031] Figure 8 Top view of the electrode assembly provided in one embodiment of the present application.

[0032] Figure 9 In one embodiment of the present application along Figure 8 Cross-sectional view taken along the center line A-A.

[0033] Figure 10 Overall schematic diagram of the electrical device provided in one embodiment of the present application.

[0034] Description of the main component symbols 1000, electrical device; 100, secondary battery; 10, electrode sheet; 101, protruding portion; 10a, positive electrode sheet; 10b, negative electrode sheet; 11, current collector; 111, first slot; 111a, first positive slot; 111b, first negative slot; 112, second slot; 112a, second positive slot; 112b, second negative slot; 113, third slot; 113a, third positive slot; 113b, third negative slot; 20, tab; 20a, positive tab; 20b, negative tab; 21, first tab bundle; 22, second tab bundle; 30, insulating member; 40, housing; 401, first side sealing portion; 402, second side sealing portion; 403, top sealing portion; 41, first housing; 42, second housing; 50, electrode assembly; 501, first notch portion; 502, second notch portion; 51, separator; 60, first adapter; 70, second adapter; 80, tab glue; X, first direction; Y, second direction. Detailed implementation manners

[0035] Next, the technical solutions in the embodiments of the present application will be described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments.

[0036] It should be noted that when an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element present at the same time. When an element is considered to be "disposed on" another element, it can be directly disposed on the other element or there may be an intermediate element present at the same time.

[0037] Unless otherwise specified, the term "plurality" used herein refers to two or more.

[0038] The terms "first", "second", etc. are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order or primary-secondary relationship of the indicated technical features.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. The terms used in the description of this application herein are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0040] Next, some embodiments of the present application will be described in conjunction with the accompanying drawings. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0041] Please refer to Figures 1 to 5 , an embodiment of the present application provides a pole piece 10. The pole piece 10 includes a current collector 11. On one side in the width direction of the current collector 11, the current collector 11 is provided with a plurality of first slots 111 and a plurality of second slots 112. The formation methods of the first slots 111 and the second slots 112 include but are not limited to cutting the current collector 11. Each of the first slots 111 is provided with one pole tab 20 or two pole tabs 20 arranged at intervals. For example, one of the first slots 111 is provided with one pole tab 20, and the other part of the first slots 111 is provided with two pole tabs 20 arranged at intervals; or, each of the first slots 111 is provided with one pole tab 20; or, each of the first slots 111 is provided with two pole tabs 20 arranged at intervals. No pole tab 20 is provided in the second slot 112. Along the length direction of the current collector 11, an odd number of second slots 112 are provided between two adjacent first slots 111. The so-called odd number is a positive odd number, such as one, three, five or seven, etc.

[0042] In some embodiments, when there is one tab 20 in the first slot 111, the tab 20 is located on one side of the first slot 111 along the slot depth direction.

[0043] In some embodiments, when there are two tabs 20 arranged at intervals in the first slot 111, the two tabs 20 are respectively located on both sides of the first slot 111 along the slot depth direction. In some embodiments, the two tabs 20 in the first slot 111 are symmetrically arranged along the slot depth direction.

[0044] The above tab 20 is arranged in the first slot 111. When the electrode tab 10 participates in winding to form the electrode assembly 50 of the secondary battery 100, the space required for the tab 20 along its protruding direction can be reduced, which is beneficial to improving the energy density of the secondary battery 100.

[0045] Along the length direction of the current collector 11, an odd number of second slots 112 are arranged between two adjacent first slots 111. When the electrode tab 10 participates in winding to form the electrode assembly 50 of the secondary battery 100, by making the first slot 111 and the second slot 112 located on different side bends of the winding structure respectively, the possibility of interference between the first slot 111 and the second slot 112 along the thickness of the electrode assembly 50 can be reduced, which is beneficial to reducing the possibility of interference between tabs 20 of different polarities along the thickness of the electrode assembly 50.

[0046] Please refer to Figures 1 to 5 , in some embodiments, the current collector 11 includes a protruding portion 101 arranged between the first slot 111 and the adjacent second slot 112, and the surface of the protruding portion 101 is coated with an active material. When the electrode tab 10 participates in winding to form the electrode assembly 50 of the secondary battery 100, it is beneficial to improve the energy density of the secondary battery 100.

[0047] In some embodiments, the electrode tab 10 includes an active material layer (not shown in the figure), and the active material layer is arranged on two surfaces of the current collector 11 opposite to each other along the thickness direction.

[0048] In some embodiments, two tabs 20 arranged at intervals are respectively provided in each first slot 111, and the first slots 111 and the second slots 112 are arranged alternately. When the electrode tab 10 participates in winding to form the electrode assembly 50 of the secondary battery 100, it is convenient to make each winding layer provided with a tab 20. It can be understood that when the first slots 111 and the second slots 112 are arranged alternately, there is only one second slot 112 between any two adjacent first slots 111.

[0049] In some embodiments, the tab 20 is integrally formed with the current collector 11. When the first slot 111 is machined on the current collector 11, the tab 20 can also be machined incidentally, which is beneficial to improving the convenience of manufacturing the electrode sheet 10. The forming method of the tab 20 includes, but is not limited to, cutting the current collector 11.

[0050] Please refer to Figure 1 or Figure 2 , in some embodiments, the first slot 111 is provided at the end of the current collector 11, that is, the edge of the slot opening of the first slot 111 coincides with the long side of the current collector 11, and the edge of the slot wall of the first slot 111 coincides with the wide side of the current collector 11. When Figure 1 or Figure 2 the electrode sheet 10 of the illustrated embodiment participates in winding to form the electrode assembly 50 of the secondary battery 100, along the winding direction of the electrode sheet 10, the tab 20 close to the wide side of the current collector 11 and a smaller part of the current collector 11 are located in the innermost winding layer, and at this time, a relatively large space remains in the innermost winding layer. It can be understood that in some other embodiments, the second slot 112 is provided at the end of the current collector 11, that is, the edge of the slot opening of the second slot 112 coincides with the long side of the current collector 11, and the edge of the slot wall of the second slot 112 coincides with the wide side of the current collector 11.

[0051] Please refer to Figure 3 , in some embodiments, neither the first slot 111 nor the second slot 112 is provided at the end of the current collector 11. When Figure 3 the electrode sheet 10 of the illustrated embodiment participates in winding to form the electrode assembly 50 of the secondary battery 100, along the winding direction of the electrode sheet 10, the tab 20 close to the wide side of the current collector 11 and a larger part of the current collector 11 are located in the innermost winding layer, and at this time, a certain space still remains in the innermost winding layer.

[0052] Please refer to Figure 4 , in some embodiments, on one side in the width direction of the current collector 11, the current collector 11 is provided with a third slot 113. The forming method of the third slot 113 includes, but is not limited to, cutting the current collector 11. A tab 20 is provided in the third slot 113. Along the length direction of the current collector 11, the third slot 113 is provided at the end of the current collector 11, and an odd number of second slots 112 are provided between the third slot 113 and the adjacent first slot 111. The so-called third slot 113 being provided at the end of the current collector 11 means that the edge of the slot opening of the third slot 113 coincides with the long side of the current collector 11, and the edge of the slot wall of the third slot 113 coincides with the wide side of the current collector 11. The so-called odd number is a positive odd number, such as one, three, five, or seven, etc. When Figure 4When the electrode tab 10 of the illustrated embodiment participates in winding to form the electrode assembly 50 of the secondary battery 100, the third slot 113 can be located at the winding starting end. Along the winding direction of the electrode tab 10, it is beneficial for the electrode tab 10 to make full use of the space of the innermost winding layer, thereby being beneficial to further improving the energy density of the secondary battery 100.

[0053] In some embodiments, from one end to the other end along the length direction of the current collector 11, the distance between two electrode tabs 20 in multiple first slots 111 increases. That is, from one end to the other end along the length direction of the current collector 11, the distance between two electrode tabs 20 in the (N + 1)-th first slot 111 is greater than the distance between two electrode tabs 20 in the N-th first slot 111, where N is a positive integer. When the electrode tab 10 participates in winding to form the electrode assembly 50 of the secondary battery 100, as the number of winding layers increases, the bending section of the winding structure needs to have a larger arc length. From one end to the other end along the length direction of the current collector 11, by making the distance between two electrode tabs 20 in multiple first slots 111 increase, it is possible to facilitate the alignment of multiple like-polarity electrode tabs 20 located in different winding layers along the thickness direction of the electrode assembly 50, which is beneficial to reducing the space required for the electrode tabs 20 along their width direction, thereby being beneficial to further improving the energy density of the secondary battery 100.

[0054] In some embodiments, from one end to the other end along the length direction of the current collector 11, the distance between two electrode tabs 20 in multiple first slots 111 increases, the slot widths of multiple first slots 111 are equal, and the slot widths of multiple second slots 112 are equal. The slot width of the first slot 111 is large enough to accommodate two electrode tabs 20 when the increasing distance reaches the maximum. It can be understood that considering the accuracy of the processing technology, when the difference between the maximum value and the minimum value of the slot widths of multiple first slots 111 is within the error range of 10% of the minimum value, the slot widths of multiple first slots 111 should also be considered equal; when the difference between the maximum value and the minimum value of the slot widths of multiple second slots 112 is within the error range of 10% of the minimum value, the slot widths of multiple second slots 112 should also be considered equal.

[0055] In some embodiments, from one end to the other end along the length direction of the current collector 11, the distance between two tab ears 20 in multiple first slots 111 increases, the slot widths of the multiple first slots 111 increase, and the slot widths of the multiple second slots 112 increase. In this case, the slot width of the first slot 111 increases as the distance between two tab ears 20 in the first slot 111 increases, which can reduce the space occupied by the first slot 111 and the second slot 112 along the length direction of the electrode tab 10. When the electrode tab 10 participates in winding to form the electrode assembly 50 of the secondary battery 100, it can facilitate the alignment of the multiple first slots 111 and the multiple second slots 112 located in different winding layers along the thickness direction of the electrode assembly 50, which is beneficial to reducing the space occupied by the first slot 111 and the second slot 112 along the width direction of the tab ear 20, thereby being beneficial to further improving the energy density of the secondary battery 100.

[0056] In some embodiments, along the length direction of the current collector 11, the slot width of the first slot 111 is W1, and the slot width of the second slot 112 is W2, where 5 mm ≤ W1 ≤ 40 mm and 5 mm ≤ W2 ≤ 40 mm. For example, W1 is 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm or any value between the listed endpoint values, and W2 is 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm or any value between the listed endpoint values.

[0057] In some embodiments, along the width direction of the current collector 11, the slot depths of the multiple first slots 111 are equal, and the slot depths of the multiple second slots 112 are equal. It can be understood that considering the accuracy of the processing technology, when the difference between the maximum value and the minimum value of the slot depths of the multiple first slots 111 is within the error range of 10% of the minimum value, the slot depths of the multiple first slots 111 should also be considered equal; when the difference between the maximum value and the minimum value of the slot depths of the multiple second slots 112 is within the error range of 10% of the minimum value, the slot depths of the multiple second slots 112 should also be considered equal.

[0058] In some embodiments, along the width direction of the current collector 11, the slot depths of the multiple first slots 111 are equal, and the slot depths of the multiple second slots 112 are equal. The slot depth of the first slot 111 is H1, and the slot depth of the second slot 112 is H2, where 1 mm ≤ H1 ≤ 15 mm and 1 mm ≤ H2 ≤ 15 mm. For example, H1 is 1 mm, 2 mm, 3 mm, 5 mm, 10 mm, 15 mm or any value between the listed endpoint values, and H2 is 1 mm, 2 mm, 3 mm, 5 mm, 10 mm, 15 mm or any value between the listed endpoint values.

[0059] Please refer to Figure 5, in some embodiments, the electrode tab 10 further includes an insulating member 30, and the insulating member 30 covers a part of the surface of the electrode tab 10 and a part of the surface of the tab 20. In some embodiments, the insulating member 30 covers a part of the surface of the electrode tab 10 and a part of the surface of the tab 20 along the thickness direction of the electrode tab 10.

[0060] In some embodiments, the insulating member 30 includes, but is not limited to, insulating glue, and the insulating glue is attached to a part of the surface of the electrode tab 10 and a part of the surface of the tab 20. In some embodiments, the insulating member 30 is formed by spraying an insulating material on a part of the surface of the electrode tab 10 and a part of the surface of the tab 20, and the insulating material includes, but is not limited to, polymer materials such as polypropylene, polyethylene terephthalate, and polyethylene.

[0061] In some embodiments, the electrode tab 10 is a positive electrode tab 10a according to its polarity, and the tab 20 is a positive tab 20a according to its polarity. In some embodiments, the electrode tab 10 is a negative electrode tab 10b according to its polarity, and the tab 20 is a negative tab 20b according to its polarity. Please refer to Figure 6 , the positive electrode tab 10a and the negative electrode tab 10b jointly participate in winding to form the electrode assembly 50 of the secondary battery 100.

[0062] In some embodiments, the electrode tab 10 is a positive electrode tab 10a according to its polarity, and the tab 20 is a positive tab 20a according to its polarity. The insulating member 30 covers a part of the surface of the positive electrode tab 10a and a part of the surface of the positive tab 20a. When the positive electrode tab 10a participates in winding to form the electrode assembly 50 of the secondary battery 100, it is beneficial to reduce the risk of short circuit caused by the burrs on the edge of the negative electrode tab 10b contacting the positive electrode tab 10a or the positive tab 20a.

[0063] Define the first slot 111 of the positive electrode tab 10a as the first positive slot 111a, define the second slot 112 of the positive electrode tab 10a as the second positive slot 112a, define the first slot 111 of the negative electrode tab 10b as the first negative slot 111b, and define the second slot 112 of the negative electrode tab 10b as the second negative slot 112b. Two positive tabs 20a are provided in the first positive slot 111a, no positive tab 20a is provided in the second positive slot 112a, two negative tabs 20b are provided in the first negative slot 111b, and no negative tab 20b is provided in the second negative slot 112b. Among them, in the electrode assembly 50 formed by the joint winding of the positive electrode tab 10a and the negative electrode tab 10b, when observed along the thickness direction of the electrode assembly 50, the first positive slot 111a, the second negative slot 112b, and the positive tab 20a are located on one side of the electrode assembly 50 and overlap each other, and the first negative slot 111b, the second positive slot 112a, and the negative tab 20b are located on the other side of the electrode assembly 50 and overlap each other.

[0064] When the current collector 11 is provided with a third slot 113, the third slot 113 of the positive electrode sheet 10a is defined as the third positive slot 113a, and the third slot 113 of the negative electrode sheet 10b is defined as the third negative slot 113b. A positive electrode tab 20a is provided in the third positive slot 113a, and a negative electrode tab 20b is provided in the third negative slot 113b. Please refer to Figure 5 When observing along the thickness direction of the electrode assembly 50, the third positive slot 113a, the second negative slot 112b, the first positive slot 111a, and the positive electrode tab 20a are located on one side of the electrode assembly 50 and overlap with each other. The third negative slot 113b, the second positive slot 112a, the first negative slot 111b, and the negative electrode tab 20b are located on the other side of the electrode assembly 50 and overlap with each other.

[0065] Please refer to Figure 7 and Figure 8 An embodiment of the present application provides a secondary battery 100, including a housing 40 and an electrode assembly 50. The electrode assembly 50 is received in the housing 40. The electrode assembly 50 includes the positive electrode sheet 10a and the negative electrode sheet 10b as described above.

[0066] When observing along the first direction X, the electrode assembly 50 has a first notch 501 and a second notch 502 (see Figure 8 ). Please refer to Figure 6 and Figure 8 Multiple first positive slots 111a and multiple second negative slots 112b are provided in the first notch 501. Multiple first negative slots 111b and multiple second positive slots 112a are provided in the second notch 502. Multiple positive electrode tabs 20a are led out from the first notch 501, and multiple negative electrode tabs 20b are led out from the second notch 502. The first direction X is the thickness direction of the electrode assembly 50. By providing multiple first positive slots 111a and multiple second negative slots 112b in the first notch 501, and multiple first negative slots 111b and multiple second positive slots 112a in the second notch 502, it is possible to arrange the positive electrode tab 20a in the first positive slot 111a in the first notch 501 and the negative electrode tab 20b in the first negative slot 111b in the second notch 502, thereby reducing the space required for the tabs 20 to occupy along their extending directions, which is beneficial to improving the energy density of the secondary battery 100.

[0067] In some embodiments, along the first direction X, the projection of the first negative slot 111b is within the projection range of the second positive slot 112a, and the projection of the second negative slot 112b is within the projection range of the first positive slot 111a. Along the direction perpendicular to the first direction X, it is convenient to make the negative electrode sheet 10b extend beyond the positive electrode sheet 10a, which is beneficial to reducing the risk of lithium deposition in the secondary battery 100.

[0068] Please refer to Figure 8In some embodiments, the first notch 501 and the second notch 502 are respectively located at different corners of the electrode assembly 50. The so-called corner refers to the intersection angle between the long side edge and the wide side edge of the electrode assembly 50. Generally, the electrode assembly 50 has four corners, and the first notch 501 and the second notch 502 are respectively located at two corners oppositely arranged along the length direction or the width direction of the electrode assembly 50, rather than at two corners diagonally arranged.

[0069] In some embodiments, the housing 40 is a metal housing, including but not limited to a steel shell. In some embodiments, the housing 40 is a flexible packaging bag, including but not limited to an aluminum-plastic film. The housing 40 includes a first housing 41 and a second housing 42, and along the first direction X, the first housing 41 and the second housing 42 are arranged opposite to each other. In some embodiments, the housing 40 is a metal housing, and the first housing 41 and the second housing 42 are welded and connected. In some embodiments, the housing 40 is a flexible packaging bag, and the first housing 41 and the second housing 42 are heat-sealed and connected.

[0070] In some embodiments, the housing 40 is a metal housing, and the first housing 41 is insulated from the second housing 42. The positive electrode of the electrode assembly 50 is electrically connected to one of the first housing 41 and the second housing 42, and the negative electrode of the electrode assembly 50 is electrically connected to the other of the first housing 41 and the second housing 42. The materials of the first housing 41 and the second housing 42 may be the same or different.

[0071] In some embodiments, the housing 40 is a metal housing, and a conductive connection is provided between the first housing 41 and the second housing 42. The secondary battery 100 includes a pole (not shown), which is insulated and provided in the housing 40. One of the positive and negative poles of the electrode assembly 50 is electrically connected to the housing 40, and the other of the positive and negative poles of the electrode assembly 50 is electrically connected to the pole. In some other embodiments, the positive and negative poles of the electrode assembly 50 are electrically connected to different poles, respectively.

[0072] In some embodiments, along the first direction X, a plurality of positive tabs 20a are gathered to form a first tab bundle 21, and a plurality of negative tabs 20b are gathered to form a second tab bundle 22. In some embodiments, the first tab bundle 21 is bent in a direction opposite to the gathering direction, and the second tab bundle 22 is bent in a direction opposite to the gathering direction.

[0073] In some embodiments, the first tab bundle 21 is accommodated in the first notch 501, and the second tab bundle 22 is accommodated in the second notch 502. This can facilitate the first tab bundle 21 not to exceed the first notch 501 along the extension direction of the positive tab 20a, and the second tab bundle 22 not to exceed the second notch 502 along the extension direction of the negative tab 20b, which is conducive to further improving the energy density of the secondary battery 100.

[0074] In some embodiments, the housing 40 is a metal housing, and the pole post is insulated and disposed on the housing 40. The first tab bundle 21 is connected to the housing 40, and the second tab bundle 22 is connected to the pole post; alternatively, the first tab bundle 21 is connected to the pole post, and the second tab bundle 22 is connected to the housing 40. The connection method includes but is not limited to welding connection.

[0075] In some embodiments, the housing 40 is a flexible packaging bag. The secondary battery 100 includes a first adapter 60 and a second adapter 70. The first adapter 60 is connected to the first tab bundle 21 and extends out of the housing 40, and the second adapter 70 is connected to the second tab bundle 22 and extends out of the housing 40. The connection method includes but is not limited to welding connection. When the first tab bundle 21 is received in the first notch 501 and the second tab bundle 22 is received in the second notch 502, the polarities of the electrode assembly 50 can be easily led out through the first adapter 60 and the second adapter 70. In some embodiments, the materials of the first adapter 60 and the second adapter 70 include one or more of conductive materials such as copper, aluminum, nickel, and nickel alloy.

[0076] In some embodiments, the first notch 501 and the second notch 502 are respectively located at different corners of the electrode assembly 50. The housing 40 is a flexible packaging bag. The first housing 41 and the second housing 42 are heat-sealed and connected, and a sealing edge is formed at the connection of the first housing 41 and the second housing 42. The sealing edge includes a first side sealing portion 401, a second side sealing portion 402, and a top sealing portion 403. When observed along the second direction Y, the first adapter 60 and the second adapter 70 are located between the first side sealing portion 401 and the second side sealing portion 402, and the top sealing portion 403 is located between the first adapter 60 and the second adapter 70. The second direction Y is the extending direction of the tab 20. The first side sealing portion 401, the second side sealing portion 402, and the top sealing portion 403 are bent toward the peripheral wall of the electrode assembly 50. By making the first notch 501 and the second notch 502 respectively located at different corners of the electrode assembly 50, it is possible to facilitate the first adapter 60 and the second adapter 70 to be respectively disposed at different corners of the housing 40, which is beneficial to reducing the interference generated when the first side sealing portion 401, the second side sealing portion 402, and the top sealing portion 403 are bent toward the peripheral wall of the electrode assembly 50, and reducing the possibility of interference between the first adapter 60 and the second adapter 70 when the top sealing portion 403 is bent toward the peripheral wall of the electrode assembly 50. Therefore, it is beneficial to reduce the possibility of the secondary battery 100 losing energy density due to the protrusion of the top sealing portion 403.

[0077] In some embodiments, the housing 40 is a flexible packaging bag, and the first housing 41 and the second housing 42 are heat-sealed and connected. The first adapter 60 is connected to the first tab bundle 21 and extends out of the housing 40, and the second adapter 70 is connected to the second tab bundle 22 and extends out of the housing 40. The secondary battery 100 includes a tab adhesive 80, and the tab adhesive 80 is disposed around the outer periphery of the first adapter 60 and the outer periphery of the second adapter 70, so that the first adapter 60 and the second adapter 70 can be respectively and hermetically connected to the housing 40.

[0078] In some embodiments, the first housing 41 and the second housing 42 together form a receiving cavity, an electrolyte is filled in the receiving cavity, and the electrode assembly 50 is disposed in the receiving cavity. Please refer to Figure 9 , the electrode assembly 50 includes a separator 51, the separator 51 separates the positive electrode sheet 10a and the negative electrode sheet 10b, and the positive electrode sheet 10a, the negative electrode sheet 10b and the separator 51 are stacked and wound to form a wound structure.

[0079] In some embodiments, the positive electrode sheet 10a includes a positive electrode current collector and a positive electrode active material layer, and the positive electrode active material layer is disposed on two opposite sides of the positive electrode current collector in the thickness direction. The material of the positive electrode current collector includes, but is not limited to, aluminum foil. The positive electrode active material layer may be formed by coating a positive electrode active material on the positive electrode current collector, and the positive electrode active material layer is adhered to the positive electrode current collector.

[0080] In some embodiments, the negative electrode sheet 10b includes a negative electrode current collector and a negative electrode active material layer, and the negative electrode active material layer is disposed on two opposite sides of the negative electrode current collector in the thickness direction. The material of the negative electrode current collector includes, but is not limited to, copper foil. The negative electrode active material layer may be formed by coating a negative electrode active material on the negative electrode current collector, and the negative electrode active material layer is adhered to the negative electrode current collector.

[0081] In some embodiments, the separator 51 is a film material such as a polyethylene film, a polypropylene film, a polyester film or a polyimide film that can be insulated.

[0082] Please refer to Figure 10 , an embodiment of the present application provides an electrical device 1000, including the secondary battery 100 as described above. By increasing the energy density of the secondary battery 100, it is beneficial to improve the battery life of the electrical device 1000. The electrical device 1000 includes, but is not limited to, electronic devices such as e-book players, mobile phones, fax machines, copiers, printers, headphones, video recorders, LCD TVs, tape recorders, radios, cameras, tablet computers and notebook computers.

[0083] In addition, those of ordinary skill in the art should recognize that the above embodiments are only used to illustrate the present application and are not intended to limit the present application. As long as appropriate changes and variations are made to the above embodiments within the substantial scope of the present application, they fall within the scope disclosed by the present application.

Claims

1. A pole piece, characterized in that: include: A current collector, wherein on one side in the width direction of the current collector, the current collector is provided with a plurality of first slots and a plurality of second slots, each of the first slots is provided with a pole ear or two pole ears arranged at intervals, and the second slots are not provided with the pole ears; along the length direction of the current collector, an odd number of the second slots are provided between two adjacent first slots.

2. The pole piece according to claim 1, characterized in that: Each of the first slots is provided with two pole ears arranged at intervals, and the first slots and the second slots are arranged alternately.

3. The pole piece according to claim 1, characterized in that: On one side of the current collector in the width direction, the current collector is provided with a third slot, in which a pole ear is provided; along the length direction of the current collector, the third slot is provided at the end of the current collector, and an odd number of the second slots are provided between the third slot and the adjacent first slot.

4. The pole piece according to claim 1, characterized in that: Along the length direction of the current collector from one end to the other end, the distance between two of the pole tabs in the first slots increases gradually.

5. The pole piece according to claim 4, characterized in that: Along the length direction of the current collector from one end to the other end, the widths of the first slots increase gradually, and the widths of the second slots increase gradually.

6. The pole piece according to claim 5, characterized in that: Along the length direction of the current collector, the width of the first slot is W1, the width of the second slot is W2, 5mm≤W1≤40mm, 5mm≤W2≤40mm.

7. The pole piece according to claim 1, characterized in that: Along the width direction of the current collector, the groove depths of the plurality of first grooves are equal, and the groove depths of the plurality of second grooves are equal, the groove depth of the first groove is H1, and the groove depth of the second groove is H2, 1mm≤H1≤15mm, 1mm≤H2≤15mm.

8. The pole piece according to claim 1, characterized in that: The pole ear and the current collector are integrally formed.

9. The pole piece according to any one of claims 1 to 8, characterized in that: The pole piece is a positive pole piece according to polarity, and the pole lug is a positive pole lug according to polarity; the pole piece also includes an insulating member, and the insulating member covers a portion of the surface of the positive pole piece and a portion of the surface of the positive pole lug.

10. The pole piece according to any one of claims 1 to 8, characterized in that: The current collector includes a protrusion disposed between the first slot and the adjacent second slot, and a surface of the protrusion is coated with an active material.

11. A secondary battery, characterized in that: include: case; An electrode assembly is accommodated in the shell; the electrode assembly comprises an electrode sheet as described in any one of claims 1 to 10, the electrode sheet is divided into a positive electrode sheet and a negative electrode sheet according to different polarities, and the electrode ear is divided into a positive electrode ear and a negative electrode ear according to different polarities; the first slot of the positive electrode sheet is defined as a first positive slot, the second slot of the positive electrode sheet is defined as a second positive slot, the first slot of the negative electrode sheet is defined as a first negative slot, and the second slot of the negative electrode sheet is defined as a second negative slot, the first positive slot is provided with two positive electrodes, the second positive slot is not provided with the positive electrode ear, the first negative slot is provided with two negative electrodes, and the second negative slot is not provided with the negative electrode ear; observed along the first direction, the electrode assembly has a first notch portion and a second notch portion, a plurality of the first positive slots and a plurality of the second negative slots are arranged in the first notch portion, a plurality of the first negative slots and a plurality of the second positive slots are arranged in the second notch portion, a plurality of the positive electrodes are led out of the first notch portion, and a plurality of the negative electrodes are led out of the second notch portion, and the first direction is the thickness direction of the electrode assembly.

12. The secondary battery according to claim 11, wherein: The electrode assembly includes a separator for separating the positive electrode sheet and the negative electrode sheet. The positive electrode sheet, the negative electrode sheet and the separator are stacked and then wound to form a winding structure.

13. The secondary battery according to claim 12, characterized in that: Along the first direction, the plurality of positive tabs are gathered to form a first tab bundle, and the plurality of negative tabs are gathered to form a second tab bundle. The first tab bundle is received in the first notch, and the second tab bundle is received in the second notch.

14. The secondary battery according to claim 13, characterized in that: The secondary battery includes a first adapter and a second adapter, wherein the first adapter is connected to the first electrode tab bundle and extends out of the shell, and the second adapter is connected to the second electrode tab bundle and extends out of the shell.

15. The secondary battery according to claim 14, characterized in that: The first notch portion and the second notch portion are respectively located at different corners of the electrode assembly; The shell is a flexible packaging bag; the shell includes a first shell and a second shell, and along the first direction, the first shell and the second shell are arranged opposite to each other and heat-sealed, and a sealing edge is formed at the connection between the first shell and the second shell; the sealing edge includes a first side seal, a second side seal and a top seal, and when viewed along the second direction, the first adapter and the second adapter are located between the first side seal and the second side seal, and the top seal is located between the first adapter and the second adapter, and the second direction is the extending direction of the electrode ear; the first side seal, the second side seal and the top seal are bent toward the peripheral wall of the electrode assembly.

16. The secondary battery according to claim 11, wherein: Along the first direction, the projection of the first negative slot is located within the projection range of the second positive slot, and the projection of the second negative slot is located within the projection range of the first positive slot.

17. An electrical equipment, characterized in that: Includes the secondary battery according to any one of claims 11 to 16.

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