Electrode assembly, battery, and electrical device

Abstract

To provide an electrode assembly that reduces the difference in electrical resistance between adjacent tabs, fully exhibits the advantages of low charging speed and low temperature rise, and improves the overcurrent capability and reduces temperature rise of the electrode assembly, and to provide a battery including the same.SOLUTION: An electrode assembly 100 includes a first pole piece 10 provided with a first tab 40, a second pole piece 20 provided with a second tab 50, and a separator 30 provided between the first pole piece and the second pole piece, and the first pole piece, the separator, and the second pole piece are wound to form the electrode assembly. The first pole piece has a first current collector and a first active material layer provided on the surface of the first current collector to form a first coating area, and the first tab and a third tab 60 are provided at an interval in the first coating area, dividing the first coating area into a first portion, a second portion, and a third portion. The length ratio of the first portion, the second portion, and the third portion is made 1:(0.5-1.5):(0.5-1.5).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to the technical field of electrochemical devices, and in particular to an electrode assembly and a battery and an electric device having the same. [Background technology]

[0002] With the advent of 5G, consumers are increasingly demanding higher battery performance for portable electronic products such as smartphones and tablet PCs. Conventional batteries suffer from the problem of high battery and overall device temperature, which can lead to reduced performance in batteries and electronic devices. Conventional batteries use a double-tab structure, which does not improve the overall battery's overcurrent capacity, resulting in high battery and overall device temperature rise. Summary of the Invention [Problem to be solved by the invention]

[0003] In view of the above, it is necessary to propose an electrode assembly and a battery and an electrical device including the electrode assembly in order to solve the above problems. [Means for solving the problem]

[0004] According to an embodiment of the present invention, there is provided an electrode assembly including a first pole piece having a first tab, a second pole piece having a second tab, and a separator film disposed between the first pole piece and the second pole piece, the electrode assembly being formed by winding the first pole piece, the separator film, and the second pole piece together. The electrode assembly further includes a third tab disposed on the first pole piece. The first pole piece includes a first current collector and a first active material layer disposed on the surface of the first current collector to form a first coating area. The first tab and the third tab are disposed at intervals in the first coating area along a first direction. The first tab and the third tab divide the first coating area into a first portion, a second portion, and a third portion along the first direction, and the length ratio of the first portion, the second portion, and the third portion is 1:(0.5-1.5):(0.5-1.5), preferably 1:(0.8-1.2):(0.8-1.2). Projections of the first tab, the second tab, and the third tab on the surface of the electrode assembly do not overlap along a third direction, the third direction is the thickness direction of the electrode assembly, and adjacent tabs along the third direction are separated by at least two layers of the first pole pieces or the second pole pieces. In this embodiment, the first direction is the longitudinal direction of the pole pieces in an unfolded state and is also the winding direction of the electrode assembly, the third direction is the thickness direction of the electrode assembly, and the third direction is perpendicular to the first direction.

[0005] In this way, the electrode assembly adds a third tab to the first pole piece to divide the current, and the first and third tabs divide the first application area at a predetermined ratio, thereby reducing the difference in electrical resistance between adjacent tabs and fully utilizing the advantages of low charging speed and low temperature rise, thereby improving the overcurrent capability and reducing temperature rise of the electrode assembly.

[0006] Furthermore, by providing multiple tabs that are offset from one another, it is possible to reduce the problem of uneven thickness of the electrode assembly due to overlapping tab thickness, which is advantageous in improving the problem of deformation of the electrode assembly during multiple charge / discharge processes. Also, by separating adjacent tabs through at least two layers of the first or second pole pieces, and preferably through four layers of pole pieces, there is a lot of gluing to the pole pieces in a single layer, which is advantageous in avoiding problems with the circulation interface due to misalignment of the pole piece interfaces.

[0007] In one embodiment, the first active material layer has a first groove and a third groove spaced apart, the first tab disposed in the first groove, and the third tab disposed in the third groove. In this embodiment, where L is the length of the first active material layer along the first direction and H is the distance between the first groove and the third groove, |L / 2-H|≦100 mm and L≧700 mm. This reduces the problem of short circuits caused by a short distance between the tabs being too small, and also facilitates dividing the first coating area into the first tab and the third tab at a predetermined ratio. Both the first groove and the third groove expose the first current collector. According to one aspect of the present application, the loss of the active material layer can expose the current collector or another coating layer coated on the surface of the current collector.

[0008] In one embodiment, the first groove penetrates the first active material layer along a second direction, and the first groove is formed on the first pole piece by gap coating, which can reduce the difficulty of the pole piece manufacturing process. The second direction is perpendicular to the first direction. The second direction is the width direction of the pole piece when the pole piece is in an expanded state, and can also be considered the longitudinal direction when the electrode assembly is wound.

[0009] In one embodiment, in the second direction, the first edge of the first groove is flush with the first side edge of the first current collector, and the second edge of the first groove is spaced apart from the second side edge of the first current collector, which is advantageous for reducing loss of the active material layer and maintaining the energy density of the battery assembly.

[0010] In one embodiment, a side edge of the first tab and a side edge of the first groove are spaced apart in the first direction to reduce contact problems of the tab with the active material.

[0011] In one embodiment, the distance between the side edge of the first tab and the side edge of the first groove in the first direction is 2 to 2.5 mm, and the first tab is attached within the tolerance limits of the device, reducing the problem of the tab contacting the active material.

[0012] In one embodiment, the width of the first tab is 6 to 8 mm and the width of the first groove is 10 to 13 mm in the first direction, thereby reducing the effect of excessive wear of the active material on the battery energy density.

[0013] In one embodiment, the first tab includes a first segment that is disposed in the first groove and connected to the first current collector, and a second segment that is bent toward the side of the first current collector that is away from the first segment, and the bent tab applies pressure to the pole piece, thereby strengthening the connection between the tab and the pole piece and reducing the problem of the tab being separated from the pole piece by external force.

[0014] In one embodiment, in the second direction, the first current collector has a first side edge and a second side edge arranged opposite each other, the first tab is provided protruding from the first side edge, and the third tab is provided protruding from the second side edge, and after the electrode assembly is wound and formed, the first tab and the third tab are located at both ends of the electrode assembly, respectively, and the distance in the first direction between the first tab and the third tab can be shortened, making it easier to miniaturize the battery.

[0015] In one embodiment, the first tab and the third tab are formed so as to extend beyond the first current collector from a portion of the side surface of the first current collector. Specifically, the first tab and the third tab can be formed by cutting out the first current collector, which can maximize the coverage area of ​​the first active material layer and is advantageous for improving the energy density of the electrode assembly.

[0016] In one embodiment, the second pole piece has a second current collector and a second active material layer provided on the surface of the second current collector to form a second coating area, and the second tab is provided in the second coating area.

[0017] In one embodiment, the second tab divides the second application area into a fourth portion and a fifth portion, and the length ratio of the fourth portion to the fifth portion along the first direction is 1:(0.5-1.5), preferably 1:(0.8-1.2), which is advantageous for reducing the difference in internal resistance between adjacent tabs.

[0018] In one embodiment, the electrode assembly further includes a fourth tab provided in the second application area and spaced apart from the second tab, the second tab and the fourth tab divide the second application area into a fourth portion, a fifth portion, and a sixth portion, and the length ratio of the fourth portion, the fifth portion, and the sixth portion in the winding direction of the second pole piece is 1:(0.5-1.5):(0.5-1.5), preferably 1:(0.8-1.2):(0.8-1.2). In this way, the current can be further divided to reduce the temperature rise of the electrode assembly.

[0019] In one embodiment, the first electrode piece is a cathode piece and the second electrode piece is an anode piece. Providing a first active material layer on both opposing surfaces of a current collector at the winding start end of the first electrode piece to make the winding start end of the first electrode piece a double-sided region, and not providing a second active material layer on both opposing surfaces of a current collector at the winding start end of the second electrode piece to make the winding start end of the second electrode piece a vacant foil region, is advantageous in reducing the occurrence of lithium deposition problems.

[0020] In one embodiment, the first pole piece and the second pole piece each have a structure in which the winding start end is a double-sided region and the winding end transitions from a single-sided region to a blank foil region, which is advantageous for balancing the active materials in both pole pieces and improving the energy density of the electrode assembly.

[0021] The present embodiment further provides a battery comprising a case and the electrode assembly according to the embodiment, the electrode assembly being disposed within the case.

[0022] The present invention also provides an electrical device including a circuit element and the battery described in the previous embodiment, the circuit element being electrically connected to the battery, such as, but not limited to, a mobile phone, a personal computer, or a mobile terminal. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a diagram showing a winding structure of an electrode assembly in one embodiment. [Figure 2] 2A and 2B are a front view and a side view of the expanded structure of the first pole piece in the electrode assembly shown in FIG. [Figure 3] 3A and 3B are a front view and a side view of the expanded structure of the second pole piece in the electrode assembly shown in FIG. [Figure 4] FIG. 4 is a front view of the electrode assembly shown in FIG. [Figure 5] 5 is a schematic diagram of both side surfaces of the first and second pole pieces in the electrode assembly shown in FIG. 1 after the tabs of the pole pieces have been removed. [Figure 6] FIG. 6 is a schematic diagram of both sides of a pole piece after removal of the tabs in one embodiment. [Figure 7] FIG. 7 is a schematic diagram of a part of the connection structure between the tab and the pole piece in one embodiment. [Figure 8] FIG. 8 is a schematic diagram of both side surfaces of the first pole piece in one embodiment. [Figure 9] FIG. 9 is a schematic diagram of both side surfaces of the second pole piece in one embodiment. [Figure 10] FIG. 10 is a schematic diagram of the winding structure of an electrode assembly having the pole pieces shown in FIGS. [Figure 11] FIG. 11 is a front view of the electrode assembly shown in FIG. [Figure 12] FIG. 12 is a schematic diagram of both side surfaces of a first pole piece in one embodiment. [Figure 13] FIG. 13 is a schematic diagram of both side surfaces of the second pole piece in one embodiment. [Figure 14] FIG. 14 is a schematic diagram of the winding structure of an electrode assembly having the pole pieces shown in FIGS. [Figure 15] FIG. 15 is a front view of the electrode assembly shown in FIG. [Figure 16] FIG. 16 is a schematic diagram of both side surfaces of a first pole piece in one embodiment. [Figure 17] FIG. 17 is a schematic diagram of both side surfaces of the second pole piece in one embodiment. [Figure 18] FIG. 18 is a schematic diagram of the winding structure of an electrode assembly having the pole pieces shown in FIGS. [Figure 19] FIG. 19 is a front view of the electrode assembly shown in FIG. [Figure 20] FIG. 20 is a schematic diagram of an electrode assembly in a comparative example. [Figure 21] 21A and 21B are a front view and a side view of the first pole piece in the electrode assembly shown in FIG. [Figure 22] 22 is a front view and a side view of the second pole piece in the electrode assembly shown in FIG. [Figure 23] FIG. 23 is a histogram of the detection results of the resistance between adjacent tabs of the electrode assembly shown in FIG. [Figure 24] FIG. 24 is a histogram of the detection results of the resistance between adjacent tabs of the electrode assembly shown in FIG. [Figure 25] FIG. 25 is a schematic diagram of a battery in one embodiment. [Figure 26] FIG. 26 is a schematic diagram of an electrical device according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0024] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be described in more detail below with reference to the accompanying drawings and examples. It should be understood that the specific examples described herein are for the purpose of illustrating the present invention and are not intended to limit the present invention.

[0025] In describing the present invention, the orientations and positional relationships indicated by terms such as "center," "vertical," "horizontal," "top," "bottom," "length," "width," "thickness," "top," "bottom," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise" are based on the orientations and positional relationships shown in the drawings. These are intended to facilitate and simplify the description of the present invention. They do not imply that the devices or elements referred to are configured or operate in a specific orientation or direction, and are not intended to limit the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or the number of technical features shown. Therefore, a feature qualified with "first" or "second" may explicitly or implicitly include one or more features. In describing the present invention, "plurality" means two or more, unless specifically limited otherwise.

[0026] The following disclosure provides many different embodiments or examples for realizing different configurations of the present invention. Hereinafter, in order to simplify the disclosure of the present invention, specific example configurations and arrangements will be described. Of course, these are merely examples and are not intended to limit the scope of the present invention. Furthermore, although the present invention repeatedly refers to numbers or letters in different embodiments, this is done for simplicity and clarity, and does not in itself represent a relationship between the different embodiments or configurations being discussed.

[0027] 1, 2, 3, and 4, in a first embodiment of the present application, an electrode assembly 100 includes a first pole piece 10, a second pole piece 20, and a separator 30. The first pole piece 10 and the second pole piece 20 have opposite polarities, and the separator 30 is provided between the first pole piece 10 and the second pole piece 20. The first pole piece 10, the separator 30, and the second pole piece 20 are wound together to form the electrode assembly 100. The first pole piece 10 is provided with a first tab 40 and a third tab 60, and the first tab 40, the third tab 60, and the first pole piece 10 have the same polarity. The second pole piece 20 is provided with a second tab 50, and the second tab 50 and the second pole piece 20 have the same polarity. In the electrode assembly 100 of the present application, the third tabs 60 are connected in parallel to divide the current flowing through the electrode assembly 100, thereby improving the overcurrent capability of the electrode assembly 100.

[0028] Specifically, referring again to FIG. 2 , the first pole piece 10 includes a first current collector 11 and a first active material layer 12 formed on the surface of the first current collector 11 to form a first coating region. The first active material layer 12 extends in a strip shape along a first direction A, and the first tab 40 and the third tab 60 are provided at intervals in the first coating region. The first tab 40 and the third tab 60 divide the first coating region into a first portion 111, a second portion 112, and a third portion 113 along the winding direction of the first pole piece 10, i.e., the winding direction of the electrode assembly 100. The length ratio of the first portion 111, the second portion 112, and the third portion 113 is 1:(0.5-1.5):(0.5-1.5), preferably 1:(0.8-1.2):(0.8-1.2). In the present embodiment, the first direction A is the longitudinal direction of the pole pieces in the deployed state, and is also the winding direction of the electrode assembly 100 .

[0029] 3, the second pole piece 20 includes a second current collector 21 and a second active material layer 22 formed on the surface of the second current collector 21 to form a second coating area, and the second tab 50 is provided in the second coating area. The second tab 50 divides the second coating area into a fourth portion 211 and a fifth portion 212, and the length ratio of the fourth portion 211 to the fifth portion 212 along the winding direction of the second pole piece 20, i.e., the winding direction of the electrode assembly 100, is 1:(0.5-1.5), preferably 1:(0.8-1.2).

[0030] In this way, the electrode assembly 100 adds a third tab 60 to the first pole piece 10 to divide the current in parallel, and the first tab 40, second tab 50, and third tab 60 divide the length of the active material layer on the first pole piece 10 and the second pole piece 20 at a predetermined ratio, thereby reducing the difference in electrical resistance between adjacent tabs and making the internal resistance between adjacent tabs approximately the same, fully demonstrating the advantages of reducing the charging speed and temperature rise, thereby improving the overcurrent capability of the electrode assembly and reducing the temperature rise of the electrode assembly.

[0031] 2 and 5, the first active material layer 12 has a first groove 121 and a third groove 122 spaced apart from each other. The first tab 40 is located in the first groove 121, and the third tab 60 is located in the third groove 122. When the length of the first active material layer 12 along the first direction A is L and the distance between the first groove 121 and the third groove 122 is H, |L / 2-H|≦100 mm and L≧700 mm are satisfied. This configuration reduces the problem of short circuits occurring due to an excessively small inter-tab distance and facilitates dividing the first application area between the first tab 40 and the third tab 60 at a predetermined ratio. The first groove 121 and the third groove 122 are formed by removing portions of the first active material layer 12. According to one embodiment of the present application, the loss of the first active material layer 12 may expose the first current collector 11 or another coating layer coated on the surface of the first current collector 11.

[0032] The second active material layer 22 has a second groove 221, and the second tab 50 is disposed in the second groove 221. The second groove 221 is located at a substantially central position of the second active material layer 22 along the first direction A. The second groove 221 is formed by removing the second active material layer 22. According to one embodiment of the present application, the removal of the second active material layer 22 may expose the second current collector 21 or another coating layer coated on the surface of the second current collector 21.

[0033] To maintain the uniformity of the active material layer, the active material layer is missing from both surfaces of the current collector in the areas corresponding to the grooves. That is, no active material layer is provided on either surface of the current collector in the first groove 121, the second groove 221, and the third groove 122, and some blank areas are formed.

[0034] Furthermore, in the second direction B, the first edge 1211 of the first groove 121 is flush with the first side edge 114 of the first current collector 11, and the second edge 1212 of the first groove 121 is spaced apart from the second side edge 115 of the first current collector 11, which is advantageous for reducing loss of the active material layer and maintaining the energy density of the battery assembly. The second direction B is perpendicular to the first direction A. The second direction B is the width direction of the pole piece in the deployed pole piece state, and can also be said to be the longitudinal direction when the electrode assembly 100 is wound. The structures of the third groove 122 and the second groove 221 are substantially the same as the structure of the first groove 121, so a description thereof will be omitted.

[0035] In the manufacturing process of the first pole piece 10 and the second pole piece 20, after applying an active material layer to the surface of the current collector, a portion of the active material in the corresponding locations of the active material layer is washed with a chemical reagent to expose the current collector, thereby obtaining the first groove 121, the second groove 221, and the third groove 122. Alternatively, before applying the active material layer to the current collector, tape may be attached to the corresponding locations, and after applying the active material layer to the surface of the current collector, the tape may be peeled off to expose the current collector, thereby obtaining the first groove 121, the second groove 221, and the third groove 122.

[0036] 6, in one embodiment of the present application, the first grooves 121 penetrate the first active material layer 12 along the second direction B. The first grooves 121 can be formed on the first pole piece 10 by gap coating, i.e., the first grooves 121, the third grooves 122, etc. can be formed by intermittently coating the active material layer on the surface of the current collector according to a predetermined procedure, thereby reducing the difficulty of the pole piece manufacturing process.

[0037] Referring again to FIGS. 2 and 3, the side of the first tab 40 and the side of the first groove 121 are spaced apart along the first direction A to reduce the problem of the tab contacting the active material. Specifically, the distance between the side of the first tab 40 and the side of the first groove 121 is 2 to 2.5 mm, allowing the first tab 40 to be installed within the device tolerance limits and reducing the problem of the tab contacting the active material. In this embodiment, the width of the first tab 40 is 6 to 8 mm and the width of the first groove 121 is 10 to 13 mm in the first direction A, thereby reducing the impact on the battery energy density due to excessive wear of the active material. The dimensions of the second tab 50 and the third tab 60 are approximately the same as those of the first tab 40, and the dimensions of the second groove 221 and the third groove 122 are approximately the same as those of the first groove 121.

[0038] Referring again to FIG. 4, in the first embodiment, the first pole piece 10 is a cathode piece, and the second pole piece 20 is an anode piece, and when the electrode assembly 100 is wound and formed, the first tab 40, the second tab 50, and the third tab 60 are located at the same end of the electrode assembly 100, and the second tab 50 is provided spaced apart between the first tab 40 and the third tab 60.

[0039] Furthermore, projections of the first tab 40, the second tab 50, and the third tab 60 on the surface of the electrode assembly 100 do not overlap along the third direction C. The third direction C is perpendicular to the first direction A. In this embodiment, the third direction C corresponds to the thickness direction of the electrode assembly 100. By staggering the tabs, the electrode assembly 100 can be prevented from having uneven thickness due to overlapping tabs, which is advantageous in improving the deformation of the electrode assembly during multiple charge / discharge cycles. In the third direction C, adjacent tabs are separated by at least two layers of the first pole piece 10 or the second pole piece 20, preferably four layers of pole pieces. This allows for more adhesive bonding to a single layer of pole pieces, which is advantageous in avoiding circulation interface problems due to misalignment of the pole piece interfaces.

[0040] 2 and 7, the first tab 40 further includes a first segment 41 disposed in the first groove 121 and connected to the first current collector 11, and a second segment 42 formed by bending the first current collector 11 toward the side away from the first segment 41. The bent tab applies pressure to the pole piece, thereby strengthening the connection between the tab and the pole piece and reducing the problem of the tab separating from the pole piece due to external force.

[0041] In an embodiment of the present application, the first tab 40 and the third tab 60 may be formed so as to protrude from a portion of a side surface of the first current collector 11. The second tab 50 may be formed so as to protrude from a portion of a side surface of the second current collector 21. Specifically, the first tab 40 and the third tab 60 may be formed by cutting out the first current collector 11, and the second tab 50 may be formed by cutting out the second current collector 21. This can maximize the coverage area of ​​the first active material layer 12 and the second active material layer 22, which is advantageous for improving the energy density of the electrode assembly 100.

[0042] 8, 9, 10, and 11, the electrode assembly 200 of the second embodiment is substantially similar to the electrode assembly 100 of the first embodiment, except that in the second embodiment, the first pole piece 10 is an anode piece, and the corresponding first tab 40 and third tab 60 are positive tabs, and the second pole piece 20 is a cathode piece, and the corresponding second tab 50 is a negative tab. After the electrode assembly 200 is wound and formed, the first tab 40, the second tab 50, and the third tab 60 are located at the same end of the electrode assembly 200, and the second tab 50 is provided with a gap between the first tab 40 and the third tab 60.

[0043] 12, 13, 14, and 15, the electrode assembly 300 of the third embodiment is substantially similar to the electrode assembly 100 of the first embodiment, but differs in that the first tab 40 protrudes from the first side edge 114 of the first current collector 11, the third tab 60 protrudes from the second side edge 115 of the first current collector 11, and the second tab 50 is installed in the same direction as the first tab 50 on the second pole piece 20. After the electrode assembly 300 is wound and formed, the second tab 50 and the first tab 40 are located at the same end of the electrode assembly 300, and the first tab 40 and the third tab 60 are located at opposite ends of the electrode assembly 300, thereby shortening the distance between the first tab 40 and the third tab 60 in the first direction A, facilitating miniaturization of the battery.

[0044] 16, 17, 18, and 19, the electrode assembly 400 of the fourth embodiment is substantially similar to the electrode assembly 100 of the first embodiment, but differs in that the fourth embodiment further includes a fourth tab 70 disposed in the second application area and spaced apart from the second tab 50. The second tab 50 and the fourth tab 70 divide the second application area into a fourth portion 211, a fifth portion 212, and a sixth portion 213. The length ratio of the fourth portion 211, the fifth portion 212, and the sixth portion 213 along the winding direction of the second pole piece is 1:(0.5-1.5):(0.5-1.5), preferably 1:(0.8-1.2):(0.8-1.2). In this way, the current can be further divided, thereby reducing the temperature rise of the electrode assembly 400.

[0045] After the electrode assembly 400 is wound, the first tab 40, the second tab 50, the third tab 60, and the fourth tab 70 are located at the same end of the electrode assembly 400, and the second tab 50 and the fourth tab 70 are spaced apart from each other between the first tab 40 and the third tab 60.

[0046] In one embodiment of the present application, the first pole piece 10 is a cathode piece, and the second pole piece 20 is an anode piece. A first active material layer 12 is provided on both opposing sides of the winding start current collector of the first pole piece 10, forming a double-sided region at the winding start end of the first pole piece 10. A second active material layer 22 is not provided on both opposing sides of the winding start current collector of the second pole piece 20, forming a blank foil region at the winding start end of the second pole piece 20, which is advantageous in reducing the occurrence of lithium deposition problems within the electrode assembly.

[0047] In one embodiment of the present application, the winding start ends of the first pole piece 10 and the second pole piece 20 are double-sided regions, and the winding end ends transition from single-sided regions to blank foil regions, which is advantageous for balancing the active materials of both pole pieces and improving the energy density of the electrode assembly.

[0048] 20, 21, and 22, the electrode assembly 100' in the first comparative example is substantially similar to the electrode assembly 100 of the first embodiment. However, the first comparative example differs in that the first tab 40 is provided in the blank foil area at the winding start end of the first pole piece 10, the third tab 60 is provided in the first coated area of ​​the first pole piece 10, and the first tab 40 and the third tab 60 do not divide the first coated area at a predetermined ratio. Combining FIG. 23 reveals that the internal resistance between adjacent tabs of the electrode assembly 100' is significantly different after winding. Referring to FIG. 24, the difference in internal resistance between adjacent tabs in the first embodiment is significantly smaller after winding the electrode assembly 100 than in the first comparative example.

[0049] The following table shows test results of charging and temperature rise data for the electrode assembly 100 of the first embodiment and the electrode assembly 100' of the first comparative example in the same charging method.

[0050] [Table 1]

[0051] As can be seen from the data in Table 1, the charging speed within 30 minutes of the electrode assembly 100 of the first embodiment is 3.2% higher than that of the first comparative example. This proves that the electrode assembly 100 of the first embodiment can reduce the difference in internal resistance between adjacent tabs by providing the first tabs 40 and the third tabs 60 in the first application area at a predetermined ratio, thereby effectively increasing the overcurrent capacity of the electrode assembly 100 and improving the charging speed of the electrode assembly 100.

[0052] [Table 2]

[0053] As can be seen from the data in Table 2, the temperature rise data of the electrode assembly 100 of the first embodiment is 4.2°C lower than that of the first comparative example, which proves that the electrode assembly 100 of the first embodiment can reduce the difference in internal resistance between adjacent tabs by arranging the first tabs 40 and the third tabs 60 in the first application area at a predetermined ratio, thereby effectively reducing the temperature rise of the electrode assembly 100 and improving the safety of the electrode assembly 100.

[0054] Referring to FIG. 25, according to an embodiment of the present invention, there is further provided a battery 500 including a case 501 and an electrode assembly described in any of the above embodiments, the electrode assembly being disposed within the case 501.

[0055] Referring to FIG. 26, according to an embodiment of the present invention, there is further provided an electric device 600, which includes a circuit element 601 and the battery 500 in the above embodiment, wherein the circuit element 601 is electrically connected to the battery 500.

[0056] The electrical device 600 may be, but is not limited to, an electronic device such as a mobile phone, a personal computer, or a mobile terminal. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that other specific forms may be embodied without departing from the spirit or essential characteristics of the present invention. Therefore, each embodiment should be considered as illustrative rather than restrictive of the present invention, and the scope of the present invention is not limited by the above description, but is defined by the claims. All changes within the meaning and range of equivalent elements of the claims are encompassed by the present invention.

[0057] The above embodiments are only for illustrating the technical solutions of the present invention and are not intended to be limiting. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or equivalently substituted without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0058] Electrode assembly 100, 200, 300, 400, 100' First pole piece 10 First current collector 11 Part 1 111 Part 2 112 Part 3 113 1st side 114 2nd side 115 First active material layer 12 1st groove 121 First Edge 1211 Second Edge 1212 3rd groove 122 Second pole piece 20 Second current collector 21 Part 4 211 Part 5 212 Part 6 213 Second active material layer 22 2nd groove 221 Separation membrane 30 First tab 40 1st segment 41 Second segment 42 Second Tab 50 Third tab 60 Tab 4: 70 battery 500 Case 501 Electrical Equipment 600 Circuit element 601

Claims

1. An electrode assembly, a first pole piece provided with a first tab; a second pole piece provided with a second tab; a separation membrane provided between the first pole piece and the second pole piece, the first pole piece, the separator, and the second pole piece are wound together to form the electrode assembly; The electrode assembly further includes a third tab provided on the first pole piece, the first pole piece has a first current collector and a first active material layer provided on a surface of the first current collector to form a first coating area, the first tab and the third tab are provided in the first coating area along a first direction with a gap therebetween, the first direction being a winding direction of the electrode assembly, Along the first direction, the first tab and the third tab divide the first application area into a first portion, a second portion, and a third portion, and a length ratio of the first portion, the second portion, and the third portion is 1:(0.5-1.5):(0.5-1.5); projections of the first tab, the second tab, and the third tab on a surface of the electrode assembly do not overlap along a third direction, the third direction being a thickness direction of the electrode assembly; an electrode assembly, wherein adjacent tabs along the third direction are separated by at least two layers of the first pole pieces or the second pole pieces;

2. a first groove and a third groove are provided in the first active material layer at an interval, the first tab is provided in the first groove, and the third tab is provided in the third groove; when a length of the first active material layer along the first direction is L and a distance between the first groove and the third groove is H, |L / 2−H|≦100 mm and L≧700 mm; The electrode assembly of claim 1 , wherein the first groove and the third groove both expose the first current collector.

3. The electrode assembly of claim 2 , wherein the first groove penetrates the first active material layer along a second direction perpendicular to the first direction.

4. 3. The electrode assembly of claim 2, wherein a first edge of the first groove is flush with a first side edge of the first current collector, and a second edge of the first groove is spaced apart from a second side edge of the first current collector, along a second direction perpendicular to the first direction.

5. The electrode assembly of claim 2 , wherein a side of the first tab and a side of the first groove are spaced apart from each other along the first direction.

6. 6. The electrode assembly of claim 5, wherein a distance between a side of the first tab and a side of the first groove in the first direction is 2 to 2.5 mm.

7. 6. The electrode assembly of claim 5, wherein the width of the first tab is 6 to 8 mm and the width of the first groove is 10 to 13 mm along the first direction.

8. 3. The electrode assembly of claim 2, wherein the first tab includes: a first segment disposed in the first groove and connected to the first current collector; and a second segment connected to the first segment, not disposed in the first groove, and bent from one end connected to the first segment toward a side of the first current collector away from the first segment.

9. 2. The electrode assembly of claim 1, wherein the first current collector has a first side edge and a second side edge that are disposed opposite each other in the second direction, the first tab protruding from the first side edge, and the third tab protruding from the second side edge.

10. The electrode assembly of claim 1 , wherein the first and third tabs are formed on a side surface of the first current collector and protrude from the first current collector.

11. 2. The electrode assembly of claim 1, wherein the second pole piece comprises a second current collector and a second active material layer formed on a surface of the second current collector to form a second coating area, and the second tab is provided in the second coating area.

12. 12. The electrode assembly of claim 11, wherein the second tab divides the second coating area into a fourth portion and a fifth portion, and a length ratio of the fourth portion to the fifth portion along the winding direction of the second pole piece is 1:(0.5-1.5).

13. 12. The electrode assembly of claim 11, further comprising a fourth tab provided in the second application area and spaced apart from the second tab, wherein the second tab and the fourth tab divide the second application area into a fourth portion, a fifth portion, and a sixth portion, and a length ratio of the fourth portion, the fifth portion, and the sixth portion along the first direction is 1:(0.5-1.5):(0.5-1.5).

14. A battery, A battery comprising a case and the electrode assembly according to any one of claims 1 to 13, wherein the electrode assembly is provided within the case.

15. An electrical device, 15. An electrical device comprising: a circuit element; and the battery according to claim 14, said circuit element being electrically connected to said battery.

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