Electrode assembly and battery

Abstract

The utility model provides an electrode assembly and a battery, and aims to solve the technical problem of short circuit of the electrode assembly. The electrode assembly comprises a first pole piece and a second pole piece, wherein the side edge of the first pole piece is concave inwards to form a first groove and a second groove; one end of the first flexible tab part extends into the first groove and is connected with the first pole piece; the side edge of the second pole piece is concave inwards to form a third groove and a fourth groove; one end of the second flexible tab part extends into the fourth groove and is connected with the second pole piece; the second pole piece and the first pole piece are stacked, the third groove corresponds to the first groove and is used for avoiding the first flexible tab part, and the second groove corresponds to the fourth groove and is used for avoiding the second flexible tab part; the diaphragm bag is arranged outside the second pole piece in a sleeving manner and is matched with the second pole piece in shape, and a via hole is formed in the diaphragm bag and is used for avoiding the second flexible tab part.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to an electrode assembly and a battery. Background Art

[0002] A battery cell consists of an electrode assembly and a housing that holds the electrode assembly. The electrode assembly typically includes a diaphragm and two pole pieces of opposite polarity. The diaphragm is located between the two pole pieces, which are connected to the external circuit via tabs. Because there is a height difference between the top of the tab and the top of the pole piece, when the electrode assembly is installed in the housing, the area within the housing corresponding to the height difference cannot be effectively utilized, which is not conducive to improving the energy density of the battery cell.

[0003] Related technologies create grooves in the electrode sheets, partially housing the tabs within them, thereby increasing the space utilization of the housing and, in turn, the energy density of the battery cells. However, with this approach, a tab connected to one electrode sheet can easily come into contact with a nearby electrode sheet of the opposite polarity, causing a short circuit in the electrode assembly. Utility Model Content

[0004] The embodiments of the present application provide an electrode assembly and a battery, which can improve the technical problem of short circuit of the electrode assembly.

[0005] In a first aspect, an embodiment of the present application provides an electrode assembly, comprising:

[0006] A first pole piece, wherein a side edge of the first pole piece is concave to form a first groove and a second groove;

[0007] a first flexible pole ear portion, one end of which extends into the first groove and is connected to the first pole piece;

[0008] A second pole piece, wherein a side edge of the second pole piece is concave to form a third groove and a fourth groove;

[0009] a second flexible pole ear portion, one end of the second flexible pole ear portion extends into the fourth groove and is connected to the second pole piece; the second pole piece is stacked with the first pole piece, the third groove corresponds to the first groove and is used to avoid the first flexible pole ear portion, and the second groove corresponds to the fourth groove and is used to avoid the second flexible pole ear portion;

[0010] A diaphragm bag is sleeved outside the second pole piece and is adapted to the shape of the second pole piece. A through hole is provided on the diaphragm bag, and the through hole is used to avoid the second flexible pole ear.

[0011] In one embodiment, the first pole piece includes a first current collector and a first active material layer arranged in a stacked manner, the first active material layer covers the surface of the first current collector, and one end of the first flexible pole ear portion extends into the first groove and is connected to the first current collector; and / or, the second pole piece includes a second current collector and a second active material layer arranged in a stacked manner, the second active material layer covers the surface of the second current collector, and one end of the second flexible pole ear portion extends into the fourth groove and is connected to the second current collector.

[0012] In one embodiment, the diaphragm bag includes two layers of diaphragms located on both sides of the second pole piece, and the side edges of each layer of the diaphragm are concave to form a fifth groove and a sixth groove, and the fifth groove and the sixth groove correspond to the third groove and the fourth groove respectively, and the edges of the two layers of diaphragms are hot-pressed together.

[0013] In one embodiment, the diaphragm is a ceramic adhesive-coated diaphragm, which includes a ceramic layer and a hot-melt adhesive layer stacked together, and the hot-melt adhesive layers of the two diaphragms are arranged facing each other.

[0014] In one embodiment, the width of the second flexible pole ear portion is smaller than the width of the fourth groove, and the width of the fourth groove is smaller than the width of the second groove; and / or the width of the first flexible pole ear portion is smaller than the width of the first groove, and the width of the first groove is smaller than the width of the third groove.

[0015] In one embodiment, the number of the third groove, the first groove and the first flexible pole ear portion is equal and they are arranged in one-to-one correspondence, the number of the first flexible pole ear portions is multiple, and the multiple first flexible pole ear portions are arranged in correspondence and connected together; the number of the second groove, the fourth groove and the second flexible pole ear portion is equal and they are arranged in one-to-one correspondence, the number of the second flexible pole ear portions is multiple, and the multiple second flexible pole ear portions are arranged in correspondence and connected together.

[0016] In one embodiment, a plurality of the first flexible pole ear portions are welded together and wrapped with a first insulating film at the welding position; a plurality of the second flexible pole ear portions are welded together and wrapped with a second insulating film at the welding position; and / or, the electrode assembly further includes a first pole ear and a second pole ear, a plurality of the first flexible pole ear portions are welded together with the first pole ear; a plurality of the second flexible pole ear portions are welded together with the second pole ear.

[0017] In one embodiment, the first pole piece and the second pole piece are arranged in a stacked and wound manner, and a plurality of the first grooves and a plurality of the second grooves are provided on one side edge of the first pole piece, and an area corresponding to half a circle of winding of the first pole piece is the first winding area, and a first groove and a second groove are provided on a single first winding area at intervals, and along the direction in which the first pole piece extends, the first grooves and the second grooves on two adjacent first winding areas are arranged in an opposite order; a plurality of the third grooves and a plurality of the fourth grooves are provided on one side edge of the second pole piece, and an area corresponding to half a circle of winding of the second pole piece is the second winding area, and a third groove and a fourth groove are provided on a single second winding area at intervals, and along the direction in which the second pole piece extends, the third grooves and the fourth grooves on two adjacent second winding areas are arranged in an opposite order.

[0018] In one embodiment, the first pole piece and the second pole piece are stacked, and the number of the first pole piece and the number of the second pole piece are both multiple. A single first pole piece is provided with a first groove and a second groove at intervals, and a single second pole piece is provided with a third groove and a fourth groove at intervals.

[0019] In one embodiment, one of the first pole piece and the second pole piece is a positive pole piece, and the other of the first pole piece and the second pole piece is a negative pole piece.

[0020] In a second aspect, an embodiment of the present application provides a battery comprising the above-mentioned electrode assembly.

[0021] Beneficial effects of the embodiments of the present application:

[0022] In an embodiment of the present application, in an electrode assembly, a first groove and a second groove are provided on a first electrode sheet, and a third groove and a fourth groove are provided on a second electrode sheet. The first electrode sheet and the second electrode sheet are stacked, and the first groove corresponds to the third groove, and the second groove corresponds to the fourth groove. The first electrode sheet and the second electrode sheet are connected to an external circuit via a first flexible electrode ear and a second flexible electrode ear, respectively. Specifically, one end of the first flexible electrode ear extends into the first groove and is connected to the first electrode sheet, and one end of the second flexible electrode ear extends into the fourth groove and is connected to the second electrode sheet. In this way, when the electrode assembly is installed in the housing of a battery cell, the first flexible electrode ear can be deformed and bent and accommodated in the first and third grooves, and the second flexible electrode ear can also be deformed and bent and accommodated in the second and fourth grooves, thereby reducing the encroachment of the first and second flexible electrode ears on the space within the housing and improving the energy density of the battery cell.

[0023] In addition, the third groove is also configured to avoid the first flexible pole ear, thereby reducing the risk of direct contact between the first flexible pole ear and the second pole piece. The second groove is configured to avoid the second flexible pole ear, thereby reducing the risk of direct contact between the second flexible pole ear and the first pole piece. In addition, the second pole piece is housed in a diaphragm bag, which reduces the risk of direct contact between the first pole piece and the second pole piece. The diaphragm bag is adapted to the shape of the second pole piece. In this way, the diaphragm bag is attached to the outer surface of the second pole piece, especially to the inner surface of the third groove and the fourth groove, which not only avoids the first flexible pole ear and the second flexible pole ear, but also further reduces the risk of direct contact between the first flexible pole ear and the second pole piece. Since the risk of direct contact between the first pole piece and the second pole piece, the risk of direct contact between the first pole piece and the second flexible pole ear, and the risk of direct contact between the second pole piece and the first flexible pole ear are all reduced, the risk of short circuit in the electrode assembly is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 1 is a schematic diagram of the main structure of the first electrode piece in the electrode assembly provided in an embodiment of the present application;

[0026] Figure 2 yes Figure 1 Cross-sectional view along the AA axis;

[0027] Figure 3 1 is a schematic diagram of the main structure of the second electrode piece in the electrode assembly provided in an embodiment of the present application;

[0028] Figure 4 yes Figure 3 Cross-sectional view along the BB direction;

[0029] Figure 5 Schematic diagram of the assembly structure of the second electrode sheet and the diaphragm bag in the electrode assembly provided in an embodiment of the present application;

[0030] Figure 6 yes Figure 5 Cross-sectional view in CC direction;

[0031] Figure 7 1 is a schematic diagram of the main structure of the electrode assembly provided in an embodiment of the present application;

[0032] Figure 8 It is a schematic structural diagram of a battery provided in an embodiment of the present application.

[0033] Reference numerals:

[0034] 10. Electrode assembly;

[0035] 1. First pole piece; 11. First current collector; 12. First active material layer; 13. First groove; 14. Second groove; 15. First winding area;

[0036] 2. The first flexible pole ear portion;

[0037] 3. Second pole piece; 31. Second current collector; 32. Second active material layer; 33. Third groove; 34. Fourth groove; 35. Second winding region;

[0038] 4. The second flexible pole ear;

[0039] 5. Diaphragm bag; 51. Diaphragm; 511. First diaphragm; 512. Second diaphragm; 51a. Ceramic layer; 51b. Hot melt adhesive layer;

[0040] 6. First tab;

[0041] 7. Second tab;

[0042] 100. Battery. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0044] Furthermore, it should be understood that the specific embodiments described herein are intended only to illustrate and explain the present application and are not intended to limit the present application. In this application, unless otherwise indicated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in actual use or operation, specifically the directions of the drawings in the accompanying drawings; whereas "inner" and "outer" refer to the outline of the device.

[0045] The terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the specified features. In the description of this application, "plurality" means two or more, unless otherwise specifically specified.

[0046] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections, electrical connections, or mutual communication; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to internal communication between two components or the interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0047] The terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a..." does not preclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0048] In the description of the embodiments of this application, words such as "example" or "for example" are used to indicate an example, illustration, or description. Any embodiment or design described as "for example" or "for example" in the embodiments of this application is not to be construed as being preferred or having more advantages than another embodiment or design. The use of words such as "example" or "for example" is intended to clearly present relative concepts.

[0049] To facilitate understanding of the solution of the present application, the spline curves and arrows used in the drawings are explained here: the components indicated by the spline curves without arrows are solid components, that is, components with solid structures; the components indicated by the spline curves with arrows are virtual components, that is, components without solid structures.

[0050] First, see Figures 1 to 8 The embodiment of the present application provides an electrode assembly 10, which is used in a battery 100. Here, the electrode assembly 10 can be a wound structure or a laminated structure.

[0051] Specifically, see Figures 1 to 7The electrode assembly 10 comprises a first tab 1, a first flexible tab 2, a second tab 3, a second flexible tab 4 and a diaphragm bag 5. The side edge of the first tab 1 is concave to form a first groove 13 and a second groove 14, and one end of the first flexible tab 2 extends into the first groove 13 and is connected with the first tab 1. The side edge of the second tab 3 is concave to form a third groove 33 and a fourth groove 34. One end of the second flexible tab 4 extends into the fourth groove 34 and is connected with the second tab 3. The second tab 3 is stacked with the first tab 1, the third groove 33 corresponds to the first groove 13 and the third groove 33 is used to avoid the first flexible tab 2, and the second groove 14 corresponds to the fourth groove 34 and the second groove 14 is used to avoid the second flexible tab 4. The diaphragm bag 5 is sleeved outside the second tab 3 and the shape of the diaphragm bag 5 is matched with the second tab 3. The diaphragm bag 5 is provided with a via hole (not shown in the figure), and the via hole is used to avoid the second flexible tab 4.

[0052] The first tab 1 and the second tab 3 are two kinds of tabs with opposite polarities. If the first tab 1 is a positive tab, the second tab 3 is a negative tab. If the first tab 1 is a negative tab, the second tab 3 is a positive tab. The number of the first tab 1 in the electrode assembly 10 can be one or more, and the number of the second tab 3 can be one or more. In the electrode assembly 10, the second tab 3 is usually located on one side of the first tab 1, that is, the first tab 1 is stacked with the second tab 3. As an example, the electrode assembly 10 is a winding structure, the number of the first tab 1 in the electrode assembly 10 is one, and the number of the second tab 3 is also one. The first tab 1 and the second tab 3 are stacked and wound together. As an example, the electrode assembly 10 is a laminated structure, the number of the first tab 1 in the electrode assembly 10 is multiple, and the number of the second tab 3 is also multiple. The first tab 1 and the second tab 3 are alternately distributed layer by layer. It should be noted that the two structures of the stack or the superposition in the present application can be direct contact or indirect contact.

[0053] The first tab 1 is also provided with the first groove 13 and the second groove 14. Specifically, the side edge of the first tab 1 is concave to form the first groove 13 and the second groove 14. It can be understood that the openings of the first groove 13 and the second groove 14 are located on the side edge of the first tab 1, the first groove 13 and the second groove 14 extend to the inner side of the first tab 1, and in addition, the first groove 13 and the second groove 14 penetrate the first tab 1 along the thickness direction of the first tab 1. The number of the first groove 13 on the first tab 1 can be one or more, and the number of the second groove 14 can be one or more.

[0054] The second pole piece 3 is further provided with a third groove 33 and a fourth groove 34. Specifically, the side edges of the second pole piece 3 are recessed to form the third groove 33 and the fourth groove 34. It will be understood that the notches of the third groove 33 and the fourth groove 34 are both located on the side edges of the second pole piece 3, and both extend inwardly of the second pole piece 3. In addition, along the thickness direction of the second pole piece 3, both the third groove 33 and the fourth groove 34 pass through the second pole piece 3. The number of the third groove 33 on the second pole piece 3 can be one or more, and the number of the fourth groove 34 can be one or more.

[0055] The first flexible pole ear portion 2 and the second flexible pole ear portion 4 are both electrically conductive and flexibly deformable. The first pole piece 1 can be connected to an external circuit via the first flexible pole ear portion 2, and the second pole piece 3 can be connected to an external circuit via the second flexible pole ear portion 4. The external circuit here refers to the circuit outside the battery cell. The first flexible pole ear portion 2 and the second flexible pole ear portion 4 can be the pole ear itself or a connecting structure connecting the pole ear and the pole piece. As an example, the first flexible pole ear portion 2 and the second flexible pole ear portion 4 are both metal foil strips. The first flexible pole ear portion 2 is connected to the first pole piece 1, and the second flexible pole ear portion 4 is connected to the second pole piece 3.

[0056] The first flexible pole ear portion 2 has opposite ends, one end of which extends into the first groove 13. That is, at least the width of the portion of the first flexible pole ear portion 2 extending into the first groove 13 is less than or equal to the width W12 of the first groove 13. Optionally, the width W11 of the first flexible pole ear portion 2 is less than the width W12 of the first groove 13. The length L11 of the first flexible pole ear portion 2 can be greater than, less than, or equal to the depth D11 of the first groove 13. When the length L11 of the first flexible pole ear portion 2 is greater than the depth D11 of the first groove 13, the other end of the first flexible pole ear portion 2 extends out of the first groove 13.

[0057] The second flexible pole ear portion 4 has opposite ends, one end of which extends into the fourth groove 34. That is, at least the width of the portion of the second flexible pole ear portion 4 extending into the fourth groove 34 is less than or equal to the width W23 of the fourth groove 34. Optionally, the width W21 of the second flexible pole ear portion 4 is less than the width W23 of the fourth groove 34. The length L21 of the second flexible pole ear portion 4 can be greater than, less than, or equal to the depth D21 of the fourth groove 34. When the length L21 of the second flexible pole ear portion 4 is greater than the depth D21 of the fourth groove 34, the other end of the second flexible pole ear portion 4 extends out of the fourth groove 34.

[0058] When the second pole piece 3 and the first pole piece 1 are stacked, the third groove 33 corresponds to the first groove 13, and the third groove 33 is used to avoid the first flexible pole ear portion 2, that is, the width W22 of the third groove 33 is greater than the width W11 of the first flexible pole ear portion 2. In this way, when the first flexible pole ear portion 2 is deformed and bent, the first flexible pole ear portion 2 can be accommodated in the first groove 13 and the third groove 33.

[0059] In addition, when the second pole piece 3 is stacked with the first pole piece 1, the second groove 14 corresponds to the fourth groove 34, and the second groove 14 is used to avoid the second flexible pole ear portion 4, that is, the width W13 of the second groove 14 is greater than the width W21 of the second flexible pole ear portion 4. In this way, when the second flexible pole ear portion 4 is deformed and bent, the second flexible pole ear portion 4 can be accommodated in the second groove 14 and the fourth groove 34.

[0060] The width W11 of the first flexible pole ear portion 2 refers to the distance between the two opposite sides of the first flexible pole ear portion 2 in the first direction; the length L11 of the first flexible pole ear portion 2 refers to the distance between the two opposite sides of the first flexible pole ear portion 2 in the second direction; the width W12 of the first groove 13 refers to the distance between the two opposite side walls of the first groove 13 in the first direction; the depth D11 of the first groove 13 refers to the distance between the notch of the first groove 13 and the bottom wall of the first groove 13; the width W13 of the second groove 14 refers to the distance between the two opposite side walls of the second groove 14 in the first direction; the first direction is perpendicular to the second direction. As an example, see Figure 1 , the first direction is the X direction, and the second direction is the Y direction.

[0061] The width W21 of the second flexible pole ear portion 4 refers to the distance between the two opposite sides of the second flexible pole ear portion 4 in the first direction; the length L21 of the second flexible pole ear portion 4 refers to the distance between the two opposite sides of the second flexible pole ear portion 4 in the second direction; the width W22 of the third groove 33 refers to the distance between the two opposite side walls of the third groove 33 in the first direction; the width W23 of the fourth groove 34 refers to the distance between the two opposite side walls of the fourth groove 34 in the first direction; the depth D21 of the fourth groove 34 refers to the distance between the notch of the fourth groove 34 and the bottom wall of the fourth groove 34; the first direction is perpendicular to the second direction. As an example, see Figure 3 , the first direction is the X direction, and the second direction is the Y direction.

[0062] The diaphragm bag 5 refers to a bag made of a diaphragm 51. The diaphragm 51 is also called an isolation membrane, which is generally a microporous and porous film. As an example, the diaphragm 51 is a porous polymer film or a rubber-coated diaphragm. The diaphragm bag 5 is used to load the second pole piece 3. In detail, the diaphragm bag 5 is arranged outside the second pole piece 3, and the second pole piece 3 is wrapped in the diaphragm bag 5. In this way, when the second pole piece 3 and the first pole piece 1 are stacked, the diaphragm 51 is between the second pole piece 3 and the first pole piece 1, and the diaphragm bag 5 can insulate and separate the second pole piece 3 and the first pole piece 1 to prevent the second pole piece 3 from contacting the first pole piece 1 and causing a short circuit. In addition, the diaphragm bag 5 is adapted to the shape of the second pole piece 3, so that when the second pole piece 3 is loaded in the diaphragm bag 5, the diaphragm bag 5 is attached to the outer surface of the second pole piece 3, especially to the inner surface of the third groove 33 and the fourth groove 34 to avoid the first flexible pole ear portion 2 and the second flexible pole ear portion 4. In addition, the diaphragm bag 5 is provided with a through hole for avoiding the second flexible pole ear portion 4, that is, one end of the second flexible pole ear portion 4 passes through the through hole to connect with the second pole piece 3 in the diaphragm bag 5 to achieve conductivity, while most of the second flexible pole ear portion 4 is still exposed outside the diaphragm bag 5.

[0063] In the electrode assembly 10 provided in the embodiment of the present application, a first groove 13 and a second groove 14 are provided on the first electrode sheet 1, and a third groove 33 and a fourth groove 34 are provided on the second electrode sheet 3. The first electrode sheet 1 and the second electrode sheet 3 are stacked, with the first groove 13 corresponding to the third groove 33 and the second groove 14 corresponding to the fourth groove 34. The first electrode sheet 1 and the second electrode sheet 3 are connected to an external circuit via a first flexible electrode ear 2 and a second flexible electrode ear 4, respectively. Specifically, one end of the first flexible electrode ear 2 extends into the first groove 13 and connects to the first electrode sheet 1, while one end of the second flexible electrode ear 4 extends into the fourth groove 34 and connects to the second electrode sheet 3. Thus, when the electrode assembly 10 is installed in the housing of a battery cell, the first flexible electrode ear 2 can be deformed and bent and accommodated in the first groove 13 and the third groove 33, and the second flexible electrode ear 4 can also be deformed and bent and accommodated in the second groove 14 and the fourth groove 34. This reduces the encroachment of the first flexible electrode ear 2 and the second flexible electrode ear 4 on the space within the housing, thereby improving the energy density of the battery cell.

[0064] In addition, the third groove 33 is configured to avoid the first flexible pole ear portion 2, thereby reducing the risk of direct contact between the first flexible pole ear portion 2 and the second pole piece 3. The second groove 14 is configured to avoid the second flexible pole ear portion 4, thereby reducing the risk of direct contact between the second flexible pole ear portion 4 and the first pole piece 1. In addition, the second pole piece 3 is accommodated in the diaphragm bag 5, which reduces the risk of direct contact between the first pole piece 1 and the second pole piece 3. The diaphragm bag 5 is adapted to the shape of the second pole piece 3. In this way, the diaphragm bag is attached to the outer surface of the second pole piece 3, especially to the inner surface of the third groove 33 and the fourth groove 34. This not only avoids the first flexible pole ear portion 2 and the second flexible pole ear portion 4, but also further reduces the risk of direct contact between the first flexible pole ear portion 2 and the second pole piece 3. Since the risk of direct contact between the first pole piece 1 and the second pole piece 3, the risk of direct contact between the first pole piece 1 and the second flexible pole ear portion 4, and the risk of direct contact between the second pole piece 3 and the first flexible pole ear portion 2 are all reduced, the risk of short circuit in the electrode assembly 10 is reduced.

[0065] In some embodiments, see Figure 1 and Figure 2 The first electrode piece 1 includes a first current collector 11 and a first active material layer 12 which are stacked together. The first active material layer 12 covers the surface of the first current collector 11 . One end of the first flexible electrode ear portion 2 extends into the first groove 13 and is connected to the first current collector 11 .

[0066] The first electrode 1 includes a first current collector 11 and a first active material layer 12, and the first current collector 11 and the first active material layer 12 are stacked. Specifically, the first active material layer 12 covers the surface of the first current collector 11. The number of first current collectors 11 in the first electrode 1 is usually one, and the number of first active material layers 12 can be one or more. In other words, the first active material layer 12 is provided on at least one side of the surface of the first current collector 11; for example, the first active material layer 12 can be provided on one side of the surface of the first current collector 11, or the first active material layer 12 can be provided on both sides of the surface of the first current collector 11.

[0067] The first current collector 11 is a conductor used to collect current. Its primary function is to collect the current generated by the first active material layer 12 to form a larger current output. Optionally, the first current collector 11 is typically a metal foil. As an example, the first electrode sheet 1 is a positive electrode sheet, and the first current collector 11 is aluminum foil.

[0068] The first active material layer 12 is a layer structure containing active materials, and the charging and discharging process of lithium ions is achieved by embedding and de-embedding lithium ions in the first active material layer 12. Optionally, the first active material layer 12 also contains a conductive agent and a binder. Generally, the selection of active materials, conductive agents, and binders in the first active material layer 12 is related to the type of the first active material layer 12. As an example, if the first electrode 1 is a positive electrode electrode, the first active material layer 12 is a positive electrode active material layer, and the active material, conductive agent, and binder contained in the first active material layer 12 are respectively a positive electrode active material, a positive electrode conductive agent, and a positive electrode binder. As an example, the positive electrode active material includes at least one of nickel cobalt manganese ternary material (NMC), lithium cobalt oxide (LiCoO2), lithium iron phosphate (LiFePO4, LFP), lithium manganese oxide (LiMn2O4, LMO) and lithium nickel cobalt aluminum oxide (NCA); the positive electrode conductor includes at least one of carbon black, conductive graphite, graphene and carbon nanotubes; the positive electrode binder includes at least one of organic polymers such as polyacrylic acid (PAA) and polyvinylidene fluoride (PVDF).

[0069] The first flexible pole ear portion 2 is connected to the first pole piece 1, specifically, one end of the first flexible pole ear portion 2 extends into the first groove 13 and is connected to the first current collector 11. As an example, the first flexible pole ear portion 2 and the first current collector 11 can be integrally formed or welded together.

[0070] By connecting the first flexible electrode ear portion 2 and the first current collector 11 together, the efficiency of current transmission is improved.

[0071] In some embodiments, see Figure 3 and Figure 4 The second electrode piece 3 includes a second current collector 31 and a second active material layer 32 which are stacked together. The second active material layer 32 covers the surface of the second current collector 31 . One end of the second flexible electrode ear portion 4 extends into the fourth groove 34 and is connected to the second current collector 31 .

[0072] The second electrode sheet 3 includes a second current collector 31 and a second active material layer 32, which are stacked together. Specifically, the second active material layer 32 covers the surface of the second current collector 31. The number of second current collectors 31 in the second electrode sheet 3 is usually one, and the number of second active material layers 32 can be one or more. In other words, the second active material layer 32 is provided on at least one side of the second current collector 31; for example, the second active material layer 32 can be provided on one side of the second current collector 31, or on both sides of the second current collector 31.

[0073] The second current collector 31 is a conductor used to collect current. Its primary function is to collect the current generated by the second active material layer 32 to form a larger current output. Optionally, the second current collector 31 is typically a metal foil. As an example, the second electrode sheet 3 is a negative electrode sheet, and the second current collector 31 is copper foil.

[0074] The second active material layer 32 is a layered structure containing active material. The lithium ion charge and discharge process is achieved by the intercalation and deintercalation of lithium ions within the second active material layer 32. Optionally, the second active material layer 32 also contains a conductive agent and a binder. Typically, the selection of the active material, conductive agent, and binder in the second active material layer 32 is related to the type of second active material layer 32. For example, if the second electrode sheet 3 is a negative electrode sheet, then the second active material layer 32 is a negative electrode active material layer. The active material, conductive agent, and binder contained in the second active material layer 32 are, respectively, a negative electrode active material, a negative electrode conductive agent, and a negative electrode binder. For example, the negative electrode active material includes at least one of graphite, graphene, hard carbon, soft carbon, and a silicon-based material; the negative electrode conductive agent includes at least one of carbon black, graphene, acetylene black, carbon nanotubes, and conductive graphite; and the negative electrode binder includes styrene-butadiene rubber (SBR).

[0075] The second flexible pole ear 4 is connected to the second pole piece 3, specifically, one end of the second flexible pole ear 4 extends into the fourth groove 34 and is connected to the second current collector 31. As an example, the second flexible pole ear 4 and the second current collector 31 can be integrally formed or welded together.

[0076] By connecting the second flexible electrode ear portion 4 and the second current collector 31 together, the efficiency of current transmission is improved.

[0077] As an example, the manufacturing process of the electrode (including the first electrode 1 and the second electrode 3) is as follows: providing a metal foil, sticking adhesive tape on different positions of one side edge of the metal foil, coating the metal foil with a slurry by continuous coating, the slurry containing a solvent, an active material, a conductive agent and an adhesive, drying to obtain an active material layer; during the preparation of the active material layer, the adhesive tape is heated and separated from the metal foil, exposing a partial area of ​​the metal foil, which is called an exposed area; the exposed area is die-cut, and the metal foil corresponding to a part of the exposed area is completely cut off to obtain a groove, and the metal foil corresponding to another part of the exposed area is partially cut off to form an ear.

[0078] In some embodiments, see Figure 5 and Figure 6The diaphragm bag 5 includes two layers of diaphragms 51, which are respectively located on both sides of the second pole piece 3. The side edges of each layer of diaphragm 51 are concave to form a fifth groove (not shown) and a sixth groove (not shown). The fifth groove and the sixth groove correspond to the third groove 33 and the fourth groove 34 respectively. The edges of the two layers of diaphragms 51 are hot-pressed together.

[0079] The diaphragm bag 5 includes two layers of diaphragm 51. Each layer of diaphragm 51 is provided with a fifth groove and a sixth groove. The notches of the fifth and sixth grooves are located on the side edges of the diaphragm 51 and extend inward. The fifth groove corresponds to the third groove 33 to avoid the first flexible electrode lug 2, and the sixth groove corresponds to the fourth groove 34 to avoid the second flexible electrode lug 4. The edges of the two layers of diaphragm 51 are bonded together through a hot pressing process to form the diaphragm bag 5.

[0080] For ease of distinction, the two diaphragms 51 located on either side of the second electrode 3 are referred to as the first diaphragm 511 and the second diaphragm 512. On the diaphragm bag 5, most of the edges of the first diaphragm 511 and the second diaphragm 512 are hot-pressed together, while a small portion of the edges of the first diaphragm 511 and the second diaphragm 512 remain separated, thereby forming a via.

[0081] As an example, when preparing the diaphragm bag 5, it specifically includes: connecting the second pole piece 3 and the second flexible pole ear portion 4 together in advance, laying the first diaphragm 511 and the second diaphragm 512 on the opposite side surfaces of the second pole piece 3 respectively, the fifth grooves on the first diaphragm 511 and the second diaphragm 512 correspond to the third groove 33 on the second pole piece 3, the sixth grooves on the first diaphragm 511 and the second diaphragm 512 correspond to the fourth groove 34 on the second pole piece 3, and the edges of the first diaphragm 511 and the second diaphragm 512 slightly protrude from the edges of the second pole piece 3, and part of the second flexible pole ear portion 4 is located between the first diaphragm 511 and the second diaphragm 512; the edges of the first diaphragm 511 and the second diaphragm 512 are hot pressed to obtain the diaphragm bag 5.

[0082] By configuring the diaphragm bag 5 to include two layers of diaphragm 51 with their edges heat-pressed together, the second electrode sheet 3 can be loaded into the diaphragm bag 5 during the manufacturing process of the diaphragm bag 5 , thereby reducing the difficulty of manufacturing the electrode assembly 10 .

[0083] In some embodiments, see Figure 6 The diaphragm 51 is a ceramic adhesive-coated diaphragm, which includes a stacked ceramic layer 51a and a hot melt adhesive layer 51b. The hot melt adhesive layers 51b of the two diaphragms 51 are arranged facing each other.

[0084] The hot melt adhesive layers 51b of the two separators 51 are disposed facing each other, specifically, the hot melt adhesive layer 51b of the first separator 511 is disposed face to face with the hot melt adhesive layer 51b of the second separator 512. The edges of the two separators 51 are heat-pressed together, specifically, the edges of the hot melt adhesive layer 51b of the first separator 511 are heat-pressed together with the edges of the hot melt adhesive layer 51b of the second separator 512.

[0085] It can be foreseen that in the diaphragm bag 5, the hot melt adhesive layer 51b faces inward and the ceramic layer 51a faces outward.

[0086] By setting the diaphragm 51 as a ceramic coated diaphragm including a ceramic layer 51a and a hot melt adhesive layer 51b, since the hot melt adhesive layer 51b is sticky under hot pressing conditions and the ceramic layer 51a has good thermal stability, the diaphragm 51 can not only be bonded together by the hot melt adhesive layer 51b to form a diaphragm bag 5, but the diaphragm 51 also has good thermal stability and is not easy to shrink and cause the second electrode 3 to be exposed, thereby reducing the risk of short circuit of the electrode assembly 10.

[0087] In some embodiments, see Figure 1 and Figure 3 The width W21 of the second flexible pole ear portion 4 is smaller than the width W23 of the fourth groove 34 , and the width W23 of the fourth groove 34 is smaller than the width W13 of the second groove 14 .

[0088] It can be seen that W21<W23<W13. This setting not only makes it easier for the second flexible pole ear portion 4 to be accommodated in the second groove 14 and the fourth groove 34 when it is bent, but also increases the gap between the second flexible pole ear portion 4 and the side wall of the second groove 14, reducing the risk of direct contact between the second flexible pole ear portion 4 and the first pole piece 1, thereby reducing the risk of short circuit of the electrode assembly 10.

[0089] In some embodiments, see Figure 1 and Figure 3 The width W11 of the first flexible electrode ear portion 2 is smaller than the width W12 of the first groove 13 , and the width W12 of the first groove 13 is smaller than the width W22 of the third groove 33 .

[0090] It can be seen that W11<W12<W22. This arrangement not only makes it easier for the first flexible pole ear portion 2 to be accommodated in the first groove 13 and the third groove 33 when it is bent, but also increases the gap between the side walls of the first flexible pole ear portion 2 and the third groove 33, thereby reducing the risk of the first flexible pole ear portion 2 piercing the diaphragm bag 5 and causing the first flexible pole ear portion 2 to directly contact the second pole piece 3, thereby reducing the risk of short circuit of the electrode assembly 10.

[0091] In some embodiments, the number of third grooves 33, first grooves 13 and first flexible pole ear portions 2 are equal and arranged in one-to-one correspondence, the number of first flexible pole ear portions 2 is multiple, and the multiple first flexible pole ear portions 2 are correspondingly arranged and connected together. As an example, the number of first flexible pole lugs 2 is N, and N first flexible pole lugs 2 are correspondingly provided, where N is a positive integer greater than or equal to 2. The first grooves 13 are provided in a one-to-one correspondence with the first flexible pole lugs 2, so the number of first grooves 13 is also N, and the N first grooves 13 are also corresponding to each other; the third grooves 33 are provided in a one-to-one correspondence with the first flexible pole lugs 2, so the number of third grooves 33 is also N, and the N third grooves 33 are also corresponding to each other, and the first grooves 13 and the third grooves 33 are also mutually corresponding. In this way, the N first grooves 13 and the N third grooves 33 can define a receiving groove. Furthermore, when the N first flexible pole lugs 2 are connected together, at least part of the first flexible pole lugs 2 will bend, and the bent part of the first flexible pole lug 2 can be accommodated in the receiving groove. The first flexible pole lugs 2 are connected together, which facilitates the connection of the first flexible pole lugs 2 with other components. In addition, providing multiple first flexible pole lugs 2 can reduce the risk of current density concentration in the electrode assembly 10 and improve the ability of the electrode assembly 10 to conduct current.

[0092] Similarly, the number of the second grooves 14 , the fourth grooves 34 and the second flexible pole lugs 4 are equal and arranged in one-to-one correspondence. There are multiple second flexible pole lugs 4 , and the multiple second flexible pole lugs 4 are arranged in correspondence and connected together. As an example, the number of second flexible pole lugs 4 is M, and M second flexible pole lugs 4 are correspondingly provided, where M is a positive integer greater than or equal to 2. The fourth grooves 34 are provided in a one-to-one correspondence with the second flexible pole lugs 4, so the number of fourth grooves 34 is also M, and the M fourth grooves 34 are also corresponding to each other; the second grooves 14 are provided in a one-to-one correspondence with the second flexible pole lugs 4, so the number of second grooves 14 is also M, and the M second grooves 14 are also corresponding to each other, and the second grooves 14 and the fourth grooves 34 are also corresponding to each other, so that the M second grooves 14 and the M fourth grooves 34 can define a receiving groove; further, when the M second flexible pole lugs 4 are connected together, at least part of the second flexible pole lugs 4 will bend, and the bent part of the second flexible pole lug 4 can be accommodated in the receiving groove, and the second flexible pole lugs 4 are connected together, which facilitates the connection of the second flexible pole lugs 4 to other components. In addition, providing multiple second flexible pole lugs 4 can reduce the risk of current density concentration in the electrode assembly 10 and improve the ability of the electrode assembly 10 to conduct current.

[0093] In some embodiments, multiple first flexible pole ears 2 are welded together, and a first insulating film (not shown) is wrapped around the outside of the multiple first flexible pole ears 2. Specifically, the first insulating film is wrapped around the welding positions of the multiple first flexible pole ears 2, that is, the multiple first flexible pole ears 2 are wrapped in the first insulating film, and the first insulating film is used to insulate the multiple first flexible pole ears 2, thereby reducing the risk of direct contact between the first flexible pole ears 2 and the second pole piece 3, thereby reducing the risk of short circuit of the electrode assembly 10.

[0094] Similarly, multiple second flexible pole ears 4 are welded together, and a second insulating film (not shown) is wrapped around the outside of the multiple second flexible pole ears 4. Specifically, the second insulating film is wrapped around the welding positions of the multiple second flexible pole ears 4, that is, the multiple second flexible pole ears 4 are wrapped in the second insulating film. The second insulating film is used to insulate the multiple second flexible pole ears 4, thereby reducing the risk of direct contact between the second flexible pole ears 4 and the first pole piece 1, thereby reducing the risk of short circuit of the electrode assembly 10.

[0095] In some embodiments, see Figure 7 The electrode assembly 10 further includes a first pole tab 6 and a second pole tab 7. That is, the first flexible pole tab portion 2 and the second flexible pole tab portion 4 are a connection structure for connecting the pole tabs. A plurality of first flexible pole tab portions 2 are connected together and welded to the first pole tab 6, and a plurality of second flexible pole tab portions 4 are connected together and welded to the second pole tab 7. In other words, a plurality of first flexible pole tab portions 2 are connected to the same first pole tab 6, and a plurality of second flexible pole tab portions 4 are connected to the same second pole tab 7. By providing a plurality of first flexible pole tab portions 2 and a plurality of second flexible pole tab portions 4, the ability of the electrode assembly 10 to conduct current is easily improved. The connection of a plurality of first flexible pole tab portions 2 to the same first pole tab 6 and a plurality of second flexible pole tab portions 4 to the same second pole tab 7 facilitates reducing the weight of the electrode assembly 10, thereby ensuring the energy density of the battery cell.

[0096] In some embodiments, the first pole piece 1 and the second pole piece 3 are arranged in a stacked and wound manner, that is, the electrode assembly 10 is a wound structure. A plurality of first grooves 13 and a plurality of second grooves 14 are respectively provided on one side edge of the first pole piece 1. The area corresponding to the half-turn winding of the first pole piece 1 is the first winding area 15. A first groove 13 and a second groove 14 are arranged at intervals on a single first winding area 15, and the number of first winding areas 15 is multiple. Along the direction in which the first pole piece 1 extends, the order in which the first grooves 13 and the second grooves 14 are arranged on two adjacent first winding areas 15 is opposite. As an example, on two adjacent first winding areas 15, the first groove 13, the second groove 14, the second groove 14, and the first groove 13 are arranged in sequence. A plurality of third grooves 33 and a plurality of fourth grooves 34 are provided on one side edge of the second pole piece 3. The area corresponding to a half-turn of the second pole piece 3 is defined as the second winding area 35. A third groove 33 and a fourth groove 34 are arranged alternately in a single second winding area 35. There are multiple second winding areas 35. Along the extension direction of the second pole piece 3, the third grooves 33 and the fourth grooves 34 are arranged in the opposite order in two adjacent second winding areas 35. For example, in two adjacent second winding areas 35, the third groove 33, the fourth groove 34, the fourth groove 34, and the third groove 33 are arranged in that order.

[0097] By arranging multiple first grooves 13 and multiple second grooves 14 on a single first pole piece 1, and arranging multiple third grooves 33 and multiple fourth grooves 34 on a single second pole piece 3, and then stacking and winding the first pole piece 1 and the second pole piece 3 together, the first groove 13 can correspond to the third groove 33, and the second groove 14 can correspond to the fourth groove 34.

[0098] In some embodiments, the first electrode piece 1 and the second electrode piece 3 are stacked, that is, the electrode assembly 10 has a stacked structure. There are multiple first electrode pieces 1 and multiple second electrode pieces 3, and each first electrode piece 1 is provided with a first groove 13 and a second groove 14 at intervals, and each second electrode piece 3 is provided with a third groove 33 and a fourth groove 34 at intervals.

[0099] By setting a first groove 13 and a second groove 14 on a single first pole piece 1, and setting a third groove 33 and a fourth groove 34 on a single second pole piece 3, but the number of first pole pieces 1 and the number of second pole pieces 3 are both multiple, and then stacking multiple first pole pieces 1 and multiple second pole pieces 3 together, the first groove 13 can also correspond to the third groove 33, and the second groove 14 can correspond to the fourth groove 34.

[0100] Second, see Figure 8 , an embodiment of the present application provides a battery 100 including the above-mentioned electrode assembly 10.

[0101] Optionally, the battery 100 includes a battery cell. Specifically, the battery cell includes a housing and an electrode assembly 10 , and the electrode assembly 10 is loaded in the housing.

[0102] The above is a detailed introduction to the embodiments of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of ​​the present application. At the same time, for those skilled in the art, based on the ideas of the present application, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. An electrode assembly, characterized in that: include: A first pole piece, wherein a side edge of the first pole piece is concave to form a first groove and a second groove; a first flexible pole ear portion, one end of which extends into the first groove and is connected to the first pole piece; A second pole piece, wherein a side edge of the second pole piece is concave to form a third groove and a fourth groove; a second flexible pole ear portion, one end of the second flexible pole ear portion extends into the fourth groove and is connected to the second pole piece; the second pole piece is stacked with the first pole piece, the third groove corresponds to the first groove and is used to avoid the first flexible pole ear portion, and the second groove corresponds to the fourth groove and is used to avoid the second flexible pole ear portion; A diaphragm bag is sleeved outside the second pole piece and is adapted to the shape of the second pole piece. A through hole is provided on the diaphragm bag, and the through hole is used to avoid the second flexible pole ear.

2. The electrode assembly according to claim 1, wherein The first electrode sheet includes a first current collector and a first active material layer stacked together, the first active material layer covers the surface of the first current collector, and one end of the first flexible electrode ear extends into the first groove and is connected to the first current collector; And / or, the second pole piece includes a second current collector and a second active material layer stacked together, the second active material layer covers the surface of the second current collector, and one end of the second flexible pole ear extends into the fourth groove and is connected to the second current collector.

3. The electrode assembly according to claim 1, wherein The diaphragm bag includes two layers of diaphragms located on both sides of the second pole piece, and the side edges of each layer of the diaphragm are concave to form a fifth groove and a sixth groove. The fifth groove and the sixth groove correspond to the third groove and the fourth groove respectively, and the edges of the two layers of diaphragms are hot-pressed together.

4. The electrode assembly according to claim 3, characterized in that The diaphragm is a ceramic adhesive-coated diaphragm, which includes a ceramic layer and a hot-melt adhesive layer that are stacked, and the hot-melt adhesive layers of the two diaphragms are arranged facing each other.

5. The electrode assembly according to claim 1, wherein: The width of the second flexible pole ear portion is smaller than the width of the fourth groove, and the width of the fourth groove is smaller than the width of the second groove; and / or the width of the first flexible pole ear portion is smaller than the width of the first groove, and the width of the first groove is smaller than the width of the third groove.

6. The electrode assembly according to any one of claims 1 to 5, characterized in that: The number of the third groove, the first groove and the first flexible pole ear portion is equal and they are arranged in one-to-one correspondence, the number of the first flexible pole ear portions is multiple, and the multiple first flexible pole ear portions are arranged in correspondence and connected together; the number of the second groove, the fourth groove and the second flexible pole ear portion is equal and they are arranged in one-to-one correspondence, the number of the second flexible pole ear portions is multiple, and the multiple second flexible pole ear portions are arranged in correspondence and connected together.

7. The electrode assembly according to claim 6, characterized in that Multiple first flexible pole ear portions are welded together and wrapped with a first insulating film at the welding position; multiple second flexible pole ear portions are welded together and wrapped with a second insulating film at the welding position; and / or, the electrode assembly further includes a first pole ear and a second pole ear, multiple first flexible pole ear portions are welded together with the first pole ear; multiple second flexible pole ear portions are welded together with the second pole ear.

8. The electrode assembly according to claim 6, wherein: The first pole piece and the second pole piece are stacked and wound, and a plurality of first grooves and a plurality of second grooves are provided on one side edge of the first pole piece, and an area corresponding to half a circle of the first pole piece is wound as the first winding area, and a first groove and a second groove are provided on a single first winding area at intervals, and along the direction in which the first pole piece extends, the first grooves and the second grooves on two adjacent first winding areas are arranged in an opposite order; a plurality of third grooves and a plurality of fourth grooves are provided on one side edge of the second pole piece, and an area corresponding to half a circle of the second pole piece is wound as the second winding area, and a third groove and a fourth groove are provided on a single second winding area at intervals, and along the direction in which the second pole piece extends, the third grooves and the fourth grooves on two adjacent second winding areas are arranged in an opposite order; or, The first pole piece and the second pole piece are stacked, and the number of the first pole piece and the second pole piece is multiple. A single first pole piece is provided with a first groove and a second groove at intervals, and a single second pole piece is provided with a third groove and a fourth groove at intervals.

9. The electrode assembly according to any one of claims 1 to 5, characterized in that: One of the first pole piece and the second pole piece is a positive pole piece, and the other of the first pole piece and the second pole piece is a negative pole piece.

10. A battery, characterized in that: Comprising the electrode assembly according to any one of claims 1 to 9.

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