Preparation method of electrode assembly, electrode assembly, battery monomer, battery device and power utilization device

Abstract

The invention provides a preparation method of an electrode assembly, the electrode assembly, a battery monomer, a battery device and a power utilization device. The preparation method of the electrode assembly comprises the following steps: providing a first pole piece, a first isolating membrane, a second pole piece and a second isolating membrane; the first pole piece comprises a first main body and a first tab, and the second pole piece comprises a second main body and a second tab; sequentially laminating a first pole piece, a first isolating membrane, a second pole piece and a second isolating membrane; connecting the first isolating membrane and the second isolating membrane with an edge area, close to the first tab, of the second main body; the first pole piece, the first isolating membrane, the second pole piece and the second isolating membrane are wound to form the electrode assembly, so that the connecting area of the second main body and the first isolating membrane and the connecting area of the second main body and the second isolating membrane are arranged corresponding to the first tab, and the risk of short circuit caused by contact of the first tab and the second main body is reduced; the reliability of the battery monomer is improved; and the service life of the battery monomer is prolonged.

Description

Technical Field

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

[0002] Batteries are widely used in new energy vehicles, electronic equipment and other fields. As the demand for batteries increases, higher requirements are placed on battery reliability. As the market's requirements for battery life increase, the requirements for battery reliability are also increasing. Summary of the invention

[0003] The embodiments of the present application provide a method for preparing an electrode assembly, an electrode assembly, a battery cell, a battery device, and an electrical device, which can improve the reliability of the battery.

[0004] In a first aspect, an embodiment of the present application provides a method for preparing an electrode assembly, comprising: Step S100: providing a first pole piece, a first isolation film, a second pole piece and a second isolation film; the first pole piece includes a first body and a first pole ear, the first pole ear is connected to one end of the first body, the second pole piece includes a second body and a second pole ear, the second pole ear is connected to one end of the second body; Step S200: stacking the first pole piece, the first isolation film, the second pole piece and the second isolation film in sequence; Step S300: connecting the first isolation film and the second isolation film to the edge area of ​​the second body close to the first electrode tab; Step S400: Winding the first pole piece, the first isolation membrane, the second pole piece and the second isolation membrane to form an electrode assembly, so that the connection area between the second body and the first isolation membrane and the connection area between the second body and the second isolation membrane are arranged corresponding to the first pole lug.

[0005] In the above technical scheme, the first isolation membrane and the second isolation membrane are connected to the edge area of ​​the second body close to the first pole ear, and the first pole piece, the first isolation membrane, the second pole piece and the second isolation membrane are wound to form an electrode assembly, so that the connection area between the second body and the first isolation membrane and the connection area between the second body and the second isolation membrane are arranged corresponding to the first pole ear, and at the corresponding position of the first pole ear, there is no gap between the second body and the first isolation membrane, and between the second body and the second isolation membrane, or the gap is not enough for the first pole ear to be inserted. Therefore, the risk of redundant insertion of the first pole ear between the second body and the first isolation membrane and between the second body and the second isolation membrane is reduced, thereby reducing the risk of short circuit caused by contact between the first pole ear and the second body, reducing the risk of thermal runaway of the battery cell equipped with the electrode assembly, improving the reliability of the battery cell and extending the service life of the battery cell equipped with the electrode assembly.

[0006] In some embodiments of the first aspect of the present application, step S300 includes: Step S310: bonding the first isolation film and the second isolation film to the edge region of the second body close to the first electrode tab.

[0007] In the above technical solution, the first isolation membrane and the second isolation membrane are both adhesively connected to the edge area of ​​the second body close to the first pole ear, making it more convenient to connect the first isolation membrane and the second body, and to connect the second isolation membrane and the second body, and the connection stability between the first isolation membrane and the second body, and between the second isolation membrane and the second body is better.

[0008] In some embodiments of the first aspect of the present application, before step S200, the method for preparing the electrode assembly further includes: Step S500: disposing a first cured adhesive layer on both sides of the edge area of ​​the second body close to the first electrode tab; Step S310 includes: Step S311: heating the first curing adhesive layer into an adhesive; Step S312: bonding the adhesive on both sides of the edge region of the second body close to the first electrode tab to the first isolation film and the second isolation film respectively.

[0009] In the above technical solution, by arranging the first cured adhesive layer in the edge area of ​​the second body close to the first pole ear before stacking the first pole piece, the first isolation membrane, the second pole piece and the second isolation membrane in sequence, the first cured adhesive layer has no fluidity. Therefore, during the transportation of the second pole piece, the first cured adhesive layer will not flow along the transportation direction of the second pole piece or the risk of the first cured adhesive layer detaching from the second body is low, which facilitates the bonding of the first isolation membrane and the second isolation membrane to the second body, and is beneficial to achieving stable bonding between the first isolation membrane and the second body and between the first isolation membrane and the second body, thereby facilitating improving the quality of the electrode assembly.

[0010] In some embodiments of the first aspect of the present application, step S500 includes: Step S510: coating slurry on both sides of the edge area of ​​the second body close to the first electrode tab; Step S520: drying the slurry so that the slurry forms the first cured adhesive layer on both sides of the edge area of ​​the second body close to the first electrode tab.

[0011] In the above technical solution, the slurry is applied on both sides of the edge area of ​​the second body close to the first pole ear. The process is relatively simple to implement. The slurry is then dried to form a first cured adhesive layer. After the slurry is dried and cured, it is not sticky. During the transportation of the second pole piece, the cured slurry (first cured adhesive layer) is not easy to be contaminated by bonding with other substances, and the risk of reduced bonding performance of the first cured adhesive layer due to contamination is low. The cured slurry (first cured adhesive layer) is not fluid. During the transportation of the second pole piece, the first cured adhesive layer will not flow along the transportation direction of the second pole piece or other directions, or the risk of the first cured adhesive layer detaching from the second body is low, which facilitates the bonding of the first isolation film and the second isolation film to the second body, and is conducive to achieving stable bonding between the first isolation film and the second body, and between the first isolation film and the second body, thereby facilitating the improvement of the quality of the electrode assembly.

[0012] In some embodiments of the first aspect of the present application, step S510 includes: Step S511: coating slurry on one side of the edge area of ​​the second body close to the first electrode tab; Step S512: coating slurry on the other side of the edge region of the second body close to the first electrode tab.

[0013] In the above technical solution, slurry is applied on one side of the edge area of ​​the second body close to the first pole ear, and then slurry is applied on the other side of the edge area of ​​the second body close to the first pole ear. The slurry is applied on both sides of the edge area of ​​the second body close to the first pole ear in sequence, which is beneficial to improving the coating quality.

[0014] In some embodiments of the first aspect of the present application, step S511 includes: Step S5111: coating slurry at intervals along the length direction of the second body on one side of the edge region of the second body close to the first electrode tab; The step S512 includes: Step S5121: applying slurry at intervals along the length direction of the second body on the other side of the edge region of the second body close to the first electrode tab.

[0015] In the above technical solution, the slurry is applied at intervals along the length direction of the second body on both sides of the edge area of ​​the second body close to the first pole ear, so that less area of ​​the second body is covered by the slurry, which is beneficial to the wetting of the second pole piece, thereby facilitating the cycle performance and life of the battery cell.

[0016] In some embodiments of the first aspect of the present application, step S511 includes: Step S5111: continuously coating the slurry on one side of the edge region of the second body close to the first electrode tab along the length direction of the second body; The step S512 includes: Step S5121: Continuously apply slurry along the length direction of the second body on the other side of the edge region of the second body close to the first electrode tab.

[0017] In the above technical solution, the slurry is continuously coated on both sides of the edge area of ​​the second body close to the first pole ear along the length direction of the second body, which makes coating more convenient and allows a larger area of ​​the second body to be covered by the slurry, which is beneficial to increasing the bonding area between the second body and the first isolation membrane, and between the second body and the second isolation membrane. It not only provides bonding stability, but also reduces the risk of inserting the first pole ear between the second body and the first isolation membrane, and between the second body and the second isolation membrane after being misplaced.

[0018] In some embodiments of the first aspect of the present application, after step S520, step S400 includes: Step S410: Winding the first pole piece, the first isolation film, the second pole piece and the second isolation film to form an electrode assembly; The step S311 includes: Step S3111: heating the electrode assembly to heat the first cured adhesive layer into an adhesive; The step S312 includes: Step S3121: hot pressing the electrode assembly so that the adhesive on both sides of the edge region of the second body close to the first electrode tab is bonded to the first isolation film and the second isolation film respectively.

[0019] In the above technical scheme, since the length of the second electrode piece is relatively large, after the first electrode piece, the first isolation film, the second electrode piece and the second isolation film are wound to form an electrode assembly, the electrode assembly is heated to heat the first cured adhesive layer into an adhesive. In this way, when the electrode assembly is heated, the heat can be more concentrated to heat the electrode assembly, which can reduce energy consumption. After the first cured adhesive layer is heated to form an adhesive, the electrode assembly is hot pressed so that the adhesive on both sides of the edge area of ​​the second body close to the first electrode ear are respectively bonded to the first isolation film and the second isolation film. This not only achieves the bonding of the first isolation film and the second isolation film to the second body, but also is beneficial to further molding of the electrode assembly and optimizes the preparation process of the electrode assembly.

[0020] In some embodiments of the first aspect of the present application, the method for preparing the electrode assembly further includes: Step S600: connecting the first isolation film and the second isolation film to the edge area of ​​the first body close to the second electrode tab; The step S400 includes: Step S420: Winding the first pole piece, the first isolation membrane, the second pole piece and the second isolation membrane to form an electrode assembly, so that the connection area between the first body and the first isolation membrane and the connection area between the first body and the second isolation membrane are arranged corresponding to the second pole lug.

[0021] In the above technical solution, the first isolation membrane and the second isolation membrane are both connected to the edge area of ​​the first body close to the second pole ear, and the first pole piece, the first isolation membrane, the second pole piece and the second isolation membrane are wound to form an electrode assembly, so that the connection area between the first body and the first isolation membrane and the connection area between the first body and the second isolation membrane are arranged corresponding to the second pole ear. At the corresponding position of the second pole ear, there is no gap between the first body and the first isolation membrane, and between the first body and the second isolation membrane, or the gap is not enough for the second pole ear to be inserted. Therefore, the risk of redundant insertion of the second pole ear between the first body and the first isolation membrane and between the first body and the second isolation membrane is reduced, thereby reducing the risk of short circuit caused by contact between the second pole ear and the first body, reducing the risk of thermal runaway of the battery cell equipped with the electrode assembly, and improving the reliability of the battery cell.

[0022] In some embodiments of the first aspect of the present application, step S600 includes: Step S610: bonding the first isolation film and the second isolation film to the edge area of ​​the first body close to the second electrode tab.

[0023] In the above technical solution, the first isolation membrane and the second isolation membrane are both adhesively connected to the edge area of ​​the first body close to the second pole ear, making it more convenient to connect the first isolation membrane and the first body, and to connect the second isolation membrane and the first body, and the connection stability between the first isolation membrane and the first body, and between the second isolation membrane and the first body is better.

[0024] In some embodiments of the first aspect of the present application, before step S200, the method for preparing the electrode assembly further includes: Step S800: disposing a second cured adhesive layer on both sides of the edge area of ​​the first body close to the second electrode tab; Step S610 includes: Step S611: heating the second cured adhesive layer into an adhesive; Step S612: bonding the adhesive on both sides of the edge region of the first body close to the second electrode tab to the first isolation film and the second isolation film respectively.

[0025] In the above technical solution, by arranging the second cured adhesive layer in the edge area of ​​the first main body close to the second pole ear before stacking the first pole piece, the first isolation membrane, the second pole piece and the second isolation membrane in sequence, the second cured adhesive layer does not have fluidity. Therefore, during the transportation of the first pole piece, the second cured adhesive layer will not flow along the transportation direction of the first pole piece or the risk of the second cured adhesive layer detaching from the first main body is low, which facilitates the bonding of the first isolation membrane and the second isolation membrane to the first main body, and is beneficial to achieving stable bonding between the first isolation membrane and the first main body and between the first isolation membrane and the first main body, thereby facilitating improving the quality of the electrode assembly.

[0026] In some embodiments of the first aspect of the present application, step S800 includes: Step S810: coating slurry on both sides of the edge area of ​​the first body close to the second electrode tab; Step S820: drying the slurry so that the slurry forms the second cured adhesive layer on both sides of the edge area of ​​the first body close to the second electrode tab.

[0027] In the above technical solution, the slurry is applied on both sides of the edge area of ​​the first body close to the second pole ear. The process is relatively simple to implement. The slurry is then dried to form a second cured adhesive layer. After the slurry is dried and cured, it is not sticky. During the transportation of the first pole piece, the cured slurry (second cured adhesive layer) is not easy to be contaminated by bonding with other substances, and the risk of reduced bonding performance of the second cured adhesive layer due to contamination is low. The cured slurry (second cured adhesive layer) is not fluid. During the transportation of the first pole piece, the second cured adhesive layer will not flow along the transportation direction of the first pole piece or the risk of the second cured adhesive layer detaching from the first body is low, which facilitates the bonding of the first isolation film and the second isolation film to the first body, and is conducive to achieving stable bonding between the first isolation film and the first body, and between the first isolation film and the first body, thereby facilitating the improvement of the quality of the electrode assembly.

[0028] In some embodiments of the first aspect of the present application, after step S820 and after step S420, step S611 includes: Step S6111: heating the electrode assembly to heat the second cured adhesive layer into an adhesive; The step S612 includes: Step S6121: hot pressing the electrode assembly so that the adhesive on both sides of the edge region of the first body close to the second electrode tab is bonded to the first isolation film and the second isolation film respectively.

[0029] In the above technical solution, since the length of the first pole piece is relatively large, after the first pole piece, the first isolation film, the second pole piece and the second isolation film are wound to form an electrode assembly, the electrode assembly is heated to heat the second cured adhesive layer into an adhesive. In this way, when the electrode assembly is heated, the heat can be concentrated to heat the electrode assembly, which can reduce energy consumption. After the second cured adhesive layer is heated to form an adhesive, the electrode assembly is hot-pressed so that the adhesive on both sides of the edge area of ​​the first body close to the second pole ear is respectively bonded to the first isolation film and the second isolation film, which not only realizes that the first isolation film and the second isolation film are bonded to the first body, but also facilitates further molding of the electrode assembly and optimizes the preparation process of the electrode assembly. In the case where the second body is provided with a first cured adhesive layer, heating the electrode assembly can simultaneously heat the first cured adhesive layer and the second cured adhesive layer to form an adhesive, thereby improving production efficiency.

[0030] In some embodiments of the first aspect of the present application, the method for preparing the electrode assembly further includes: Step S900: connecting edge regions of the first isolation film close to the first electrode tab and edge regions of the second isolation film close to the first electrode tab on both sides of the second body.

[0031] In the above technical solution, the edge area of ​​the first isolation membrane close to the first pole ear and the edge area of ​​the second isolation membrane close to the first pole ear on both sides of the second body are connected, so that the risk of the first pole ear being inserted between the first isolation membrane and the second body and the risk of the first pole ear being inserted between the second isolation membrane and the second body are further reduced, and the risk of short circuit caused by contact between the first pole ear and the second body is further reduced, thereby reducing the risk of thermal runaway of the battery cell equipped with the electrode assembly, improving the reliability of the battery cell and extending the service life of the battery cell equipped with the electrode assembly.

[0032] In some embodiments of the first aspect of the present application, the method for preparing the electrode assembly further includes: Step S1000: connecting edge regions of the first isolation film close to the second electrode tab and edge regions of the second isolation film close to the second electrode tab on both sides of the first body.

[0033] In the above technical solution, the edge area of ​​the first isolation membrane close to the second pole ear and the edge area of ​​the second isolation membrane close to the second pole ear on both sides of the first main body are connected, so that the risk of the second pole ear being inserted between the first isolation membrane and the first main body and the risk of the second pole ear being inserted between the second isolation membrane and the first main body are further reduced, and the risk of short circuit caused by contact between the second pole ear and the first main body is further reduced, thereby reducing the risk of thermal runaway of the battery cell equipped with the electrode assembly, improving the reliability of the battery cell and extending the service life of the battery cell equipped with the electrode assembly.

[0034] In the second aspect, an embodiment of the present application provides an electrode assembly, which includes a first pole piece, a first isolation membrane, a second pole piece and a second isolation membrane, wherein the first pole piece, the first isolation membrane, the second pole piece and the second isolation membrane are stacked in sequence and wound to form a winding structure; the first pole piece includes a first main body and a first pole ear, the first pole ear is connected to one end of the first main body, and the second pole piece includes a second main body and a second pole ear, the second pole ear is connected to one end of the second main body; wherein the first isolation membrane and the second isolation membrane are both connected to the edge area of ​​the second main body close to the first pole ear, and the connection area between the second main body and the first isolation membrane and the connection area between the second main body and the second isolation membrane are arranged corresponding to the first pole ear.

[0035] In the above technical solution, the first isolation membrane and the second isolation membrane are both connected to the edge area of ​​the second body close to the first pole ear, and the connection area between the second body and the first isolation membrane and the connection area between the second body and the second isolation membrane are arranged corresponding to the first pole ear. At the corresponding position of the first pole ear, there is no gap between the second body and the first isolation membrane, and between the second body and the second isolation membrane, or the gap is insufficient for the first pole ear to be inserted. Therefore, the risk of redundant insertion of the first pole ear between the second body and the first isolation membrane and between the second body and the second isolation membrane is reduced, thereby reducing the risk of short circuit caused by contact between the first pole ear and the second body, reducing the risk of thermal runaway of the battery cell equipped with the electrode assembly, and improving the reliability of the battery cell.

[0036] In some embodiments of the second aspect of the present application, the electrode assembly includes a first glue layer and a second glue layer, the first isolation film and the edge area of ​​the second body close to the first pole ear are bonded through the first glue layer, and the second isolation film and the edge area of ​​the second body close to the first pole ear are bonded through the second glue layer.

[0037] In the above technical solution, the first isolation membrane is bonded to the edge area of ​​the second body close to the first pole ear by the first adhesive layer, and the second isolation membrane is bonded to the edge area of ​​the second body close to the first pole ear by the second adhesive layer, so that connecting the first isolation membrane and the second body, and connecting the second isolation membrane and the second body are more convenient, and the connection stability between the first isolation membrane and the second body, and between the second isolation membrane and the second body is better.

[0038] In some embodiments of the second aspect of the present application, the electrode assembly includes a plurality of the first glue layers and a plurality of the second glue layers, the plurality of the first glue layers are arranged at intervals along the length direction of the second pole piece, and the plurality of the second glue layers are arranged at intervals along the length direction of the second pole piece.

[0039] In the above technical solution, multiple first adhesive layers are arranged at intervals along the length direction of the second pole piece, and multiple second adhesive layers are arranged at intervals along the length direction of the second pole piece, so that a smaller area of ​​the second body is covered by the slurry, which is beneficial to the wetting of the second pole piece, thereby facilitating the improvement of the cycle performance and life of the battery cell equipped with the electrode assembly.

[0040] In some embodiments of the second aspect of the present application, along the length direction of the second pole piece, the first adhesive layer is located between two adjacent second pole tabs, and the second adhesive layer is located between two adjacent second pole tabs.

[0041] In the above technical solution, the first adhesive layer and the second adhesive layer are both located between two adjacent second pole ears, and the second adhesive layer is located between two adjacent second pole ears, which reduces the risk of interference between the first adhesive layer and the second adhesive layer and the second pole ears, and is conducive to the second pole ears having better conductive properties.

[0042] In some embodiments of the second aspect of the present application, the first isolation membrane and the second isolation membrane are both connected to the edge area of ​​the first body close to the second pole ear, and the connection area between the first body and the first isolation membrane and the connection area between the first body and the second isolation membrane are arranged corresponding to the second pole ear.

[0043] In the above technical solution, the first isolation membrane and the second isolation membrane are both connected to the edge area of ​​the first body close to the second pole ear, and the connection area between the first body and the first isolation membrane and the connection area between the first body and the second isolation membrane are arranged corresponding to the second pole ear. At the corresponding position of the second pole ear, there is no gap between the first body and the first isolation membrane, and between the first body and the second isolation membrane, or the gap is insufficient for the second pole ear to be inserted. Therefore, the risk of redundant insertion of the second pole ear between the first body and the first isolation membrane and between the first body and the second isolation membrane is reduced, thereby reducing the risk of short circuit caused by contact between the second pole ear and the first body, reducing the risk of thermal runaway of the battery cell equipped with the electrode assembly, and improving the reliability of the battery cell.

[0044] In a third aspect, an embodiment of the present application provides a battery cell, wherein the battery cell includes the electrode assembly provided in the above embodiment.

[0045] In the above technical solution, the electrode assembly provided by the above embodiment has a lower risk of thermal runaway, and therefore, the reliability of the battery cell equipped with the electrode assembly is better.

[0046] In a fourth aspect, an embodiment of the present application provides a battery device, comprising the battery cell provided by the above embodiment.

[0047] In the above technical solution, the battery cell provided in the above embodiment has good reliability, and the battery device including the battery cell also has good reliability.

[0048] In a fifth aspect, an embodiment of the present application provides an electrical device, comprising the battery cell provided in the above embodiment or the battery device provided in the above embodiment.

[0049] In the above technical solution, the reliability of the battery cells and battery devices provided in the above embodiments is good, and the power consumption reliability of the power consumption device powered by the battery cells or battery devices is also good. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0051] Figure 1 A schematic diagram of the structure of a vehicle provided in some embodiments of the present application; Figure 2 An exploded view of a battery device provided in some embodiments of the present application; Figure 3 A schematic diagram of the structure of a battery cell provided in some embodiments of the present application; Figure 4 A schematic diagram of the structure of an electrode assembly provided in some embodiments of the present application; Figure 5 A flow chart of a method for preparing an electrode assembly provided in some embodiments of the present application; Figure 6 A schematic diagram of the structure of a second conveying mechanism provided in some embodiments of the present application; Figure 7 A schematic diagram of the structure of a first pole piece provided in some embodiments of the present application; Figure 8 A schematic diagram of the structure of a first pole piece provided in some other embodiments of the present application; Fig. 9 A schematic diagram of the structure of a second pole piece provided in some embodiments of the present application; Fig.10 A schematic diagram of the structure of a second pole piece provided in some other embodiments of the present application; Fig.11 A flow chart of a method for preparing an electrode assembly provided in some other embodiments of the present application; Fig.12 A flow chart of a method for preparing an electrode assembly provided in some further embodiments of the present application; Fig.13 A partial flow chart of a method for preparing an electrode assembly provided in some embodiments of the present application; Fig.14 A partial flow chart of a method for preparing an electrode assembly provided in some other embodiments of the present application; Fig.15 A partial flow chart of a method for preparing an electrode assembly provided in some further embodiments of the present application; Fig.16 A partial flow chart of a method for preparing an electrode assembly provided in some other embodiments of the present application; Fig.17A flow chart of a method for preparing an electrode assembly provided in some other embodiments of the present application; Fig.18 A flow chart of a method for preparing an electrode assembly provided in yet other embodiments of the present application; Fig.19 A partial flow chart of a method for preparing an electrode assembly provided in some embodiments of the present application; Fig. 20 Another partial flow chart of the method for preparing an electrode assembly provided in some embodiments of the present application; Fig.21 A further partial flow chart of a method for preparing an electrode assembly provided in some embodiments of the present application; Fig. 22 A flowchart of another part of the method for preparing an electrode assembly provided in some embodiments of the present application; Fig.23 A flow chart of a method for preparing an electrode assembly provided in yet other embodiments of the present application.

[0052] Icon: 1000-vehicle; 100-battery device; 10-housing; 11-first housing; 12-second housing; 20-battery cell; 21-housing; 211-housing; 2111-opening; 212-end cap; 22-electrode assembly; 221-first pole piece; 2211-first body; 22111-third end; 2212-first pole ear; 22121-first pole ear root; 2213-first current collector; 2213a-first region; 2213b-second region; 2214-first active material layer; 2215-first insulating layer; 222-first isolation membrane; 223-second pole piece; 2231-second body; 22311-first end; 2232- The second pole ear; 22321-the root of the second pole ear; 2233-the second current collector; 2233a-the third region; 2233b-the fourth region; 2234-the second active material layer; 2235-the second insulating layer; 224-the second isolation membrane; 225-the first glue layer; 226-the second glue layer; 227-the third glue layer; 228-the fourth glue layer; 23-the electrode terminal; 200-the controller; 300-the motor; 2000-the electrode assembly manufacturing equipment; 2100-the pole piece conveying mechanism; 2110-the conveying roller; 2200-the first coating mechanism; 2300-the second coating mechanism; 2400-the first drying mechanism; 2500-the second drying mechanism; 2600-the pole ear detection mechanism. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0054] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field of this application; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0055] Reference to "embodiment" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments.

[0056] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0057] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the associated objects before and after are in an "or" relationship.

[0058] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0059] The term “plurality” used in this application refers to two or more (including two).

[0060] In the embodiment of the present application, the battery cell may be a secondary battery. A secondary battery refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0061] Battery cells include, but are not limited to, lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-hydrogen batteries, nickel-cadmium batteries, lead-acid batteries, and the like.

[0062] A battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of the battery cell, active ions (such as lithium ions) are embedded and removed between the positive electrode and the negative electrode. The separator is set between the positive electrode and the negative electrode to reduce the risk of short circuit between the positive and negative electrodes, while allowing active ions to pass through.

[0063] In some embodiments, the positive electrode may be a positive electrode sheet, and the positive electrode sheet may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0064] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material is disposed on either or both of the two facing surfaces of the positive electrode current collector.

[0065] As an example, the positive electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc. may be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0066] As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides, and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials for battery cells may also be used. These positive electrode active materials may be used alone or in combination of two or more. Among them, examples of lithium-containing phosphates may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. Examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3Mn 1 / 3 O2 (also referred to as NCM 333 )、LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 )、LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 )、LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 )、LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O2) and its modified compounds, etc.

[0067] In some embodiments, the positive electrode may be a foamed metal. The foamed metal may be a nickel foam, a copper foam, an aluminum foam, an alloy foam, etc. When the foamed metal is used as the positive electrode, the positive electrode active material may not be provided on the surface of the foamed metal, but of course, the positive electrode active material may also be provided. As an example, a lithium source material, potassium metal or sodium metal may also be filled or / and deposited in the foamed metal, and the lithium source material is lithium metal and / or a lithium-rich material.

[0068] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0069] As an example, the negative electrode current collector may be a metal foil, a foamed metal or a composite current collector. For example, as the metal foil, aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc. may be used. The foamed metal may be foamed nickel, foamed copper, foamed aluminum, foamed alloy, etc. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0070] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0071] As an example, the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active material is disposed on either or both of the two facing surfaces of the negative electrode current collector.

[0072] As an example, the negative electrode active material may adopt the negative electrode active material for battery cells known in the art. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for battery cells may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0073] In some embodiments, the material of the positive electrode current collector may be aluminum, and the material of the negative electrode current collector may be copper.

[0074] In some embodiments, the separator is a separator membrane, which can be any known porous separator membrane with good chemical stability and mechanical stability.

[0075] As an example, the material of the separator may include at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer may be the same or different. The separator may be a separate component located between the positive and negative electrodes, or may be attached to the surface of the positive and negative electrodes.

[0076] In some embodiments, the battery cell further includes an electrolyte, which plays a role in conducting ions between the positive and negative electrodes. The electrolyte can be liquid, gel or solid. Among them, the liquid electrolyte includes an electrolyte salt and a solvent.

[0077] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonyl imide, lithium bistrifluoromethanesulfonyl imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium dioxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0078] In some embodiments, the solvent may include at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclopentane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone. The solvent may also be an ether solvent. The ether solvent may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether and crown ether.

[0079] Among them, the gel electrolyte includes a skeleton network with a polymer as the electrolyte, combined with an ionic liquid-lithium salt.

[0080] Among them, solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0081] As an example, the polymer solid electrolyte may be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, a single ion polymer, polyionic liquid-lithium salt, cellulose, and the like.

[0082] As an example, the inorganic solid electrolyte may include an oxide solid electrolyte (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON film), a sulfide solid electrolyte (crystalline lithium superion conductor (lithium germanium phosphosulfide, silver germanium sulfide), amorphous sulfide) and one or more of a halide solid electrolyte, a nitride solid electrolyte and a hydride solid electrolyte.

[0083] As an example, the composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0084] In some embodiments, the electrode assembly is a wound structure, wherein the positive electrode sheet and the negative electrode sheet are wound into a wound structure.

[0085] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or polygonal.

[0086] In some embodiments, the electrode assembly is provided with tabs, which can lead current out of the electrode assembly. The tabs include a positive tab and a negative tab.

[0087] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing may be a steel housing, an aluminum housing, a plastic housing (such as polypropylene), a composite metal housing (such as a copper-aluminum composite housing), or an aluminum-plastic film.

[0088] As an example, the battery cell may be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell or a battery cell of other shapes. The prismatic battery cell includes a square-shell battery cell, a blade-shaped battery cell, a polygonal battery cell, such as a hexagonal battery cell.

[0089] The battery apparatus mentioned in the embodiments of the present application may include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly may include a plurality of battery cells, and the plurality of battery cells 20 may be connected in series, in parallel or in mixed connection through a busbar component.

[0090] In some embodiments, a battery cell assembly is generally formed by arranging a plurality of battery cells; as an example, the battery cell assembly may be a battery module, which is formed by arranging and fixing a plurality of battery cells to form an independent module.

[0091] As an example, a battery module may be formed by bundling a plurality of battery cells by cable ties.

[0092] In some embodiments, the battery device may be a battery pack, which may include a case and one or more battery cell assemblies, wherein the battery cell assemblies are accommodated in the case.

[0093] As an example, the battery cell assembly may be a battery module, and the battery cell assembly may be accommodated in the box by fixing the battery module in the box.

[0094] As an example, the battery cell assembly may also be housed in the case by directly fixing a plurality of battery cells to the case.

[0095] As an example, the box may include a first box and a second box. The first box and the second box are buckled together to form a closed space inside the box to accommodate the battery cell assembly. The closed here means covered or closed, which can be sealed or unsealed. The first box can be a top cover or a bottom plate.

[0096] As an example, the box body may include a top cover, a frame and a bottom plate. The top cover and the bottom plate are respectively connected to the frame, so that a closed space is formed inside the box body to accommodate the battery cell assembly.

[0097] As an example, the box body can be used as a part of the chassis structure of the vehicle. For example, the top cover of the box body can become at least a part of the floor of the vehicle, or the frame of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0098] In some embodiments, the battery device refers to an energy storage device, which includes a box body, at least one side of which is provided with a door. The energy storage device includes an energy storage container, an energy storage cabinet, and the like.

[0099] Batteries have outstanding advantages such as high energy density, low environmental pollution, high power density, long service life, wide adaptability, and low self-discharge coefficient. They are an important part of the development of new energy today. The development of battery technology must consider many design factors at the same time, such as performance parameters such as energy density, cycle life, discharge capacity, and charge and discharge rate. In addition, the reliability of the battery must also be considered.

[0100] During the extrusion process of the electrode assembly of the battery cell into the shell, redundant pole ears are prone to occur. During use, the redundant pole ears may be inserted into the active material area of ​​the pole piece with the opposite polarity to the pole ears, causing a short circuit. After the short circuit, the battery cell may experience thermal runaway, resulting in reduced reliability of the battery cell and shortened service life.

[0101] Based on the above considerations, in order to alleviate the problem that the redundant pole tabs of the battery cell may be inserted into the active material area of ​​the pole piece with the opposite polarity to the pole tab during use and cause a short circuit, an embodiment of the present application provides a method for preparing an electrode assembly, and the method for preparing the electrode assembly includes step S100: providing a first pole piece, a first isolation film, a second pole piece and a second isolation film; the first pole piece includes a first body and a first pole tab, the first pole tab is connected to one end of the first body, the second pole piece includes a second body and a second pole tab, and the second pole tab is connected to one end of the second body; Step S200: stacking a first pole piece, a first isolation film, a second pole piece, and a second isolation film in sequence; Step S300: connecting the first isolation film and the second isolation film to the edge area of ​​the second body close to the first electrode tab; Step S400: Winding the first pole piece, the first isolation membrane, the second pole piece and the second isolation membrane to form an electrode assembly, so that the connection area between the second body and the first isolation membrane and the connection area between the second body and the second isolation membrane are arranged corresponding to the first pole ear.

[0102] The first isolation membrane and the second isolation membrane are connected to the edge area of ​​the second body close to the first pole ear, and the first pole piece, the first isolation membrane, the second pole piece and the second isolation membrane are wound to form an electrode assembly, so that the connection area between the second body and the first isolation membrane and the connection area between the second body and the second isolation membrane are arranged corresponding to the first pole ear, and at the corresponding position of the first pole ear, there is no gap between the second body and the first isolation membrane, and between the second body and the second isolation membrane, or the gap is insufficient for the first pole ear to be inserted. Therefore, the risk of redundant insertion of the first pole ear between the second body and the first isolation membrane and between the second body and the second isolation membrane is reduced, thereby reducing the risk of short circuit caused by contact between the first pole ear and the second body, reducing the risk of thermal runaway of the battery cell equipped with the electrode assembly, improving the reliability of the battery cell and extending the service life of the battery cell equipped with the electrode assembly.

[0103] The technical solutions described in the embodiments of the present application are applicable to various electrical devices using battery cells and battery devices, such as mobile phones, portable devices, laptop computers, electric vehicles, electric toys, electric tools, vehicles, ships and spacecraft, for example, spacecraft include airplanes, rockets, space shuttles and spacecraft, etc.

[0104] For the convenience of description, the following embodiments are described by taking the electric device as a vehicle as an example.

[0105] Please refer to Figure 1 , Figure 1 The schematic diagram of the structure of the vehicle 1000 provided in some embodiments of the present application. The vehicle 1000 is provided with a battery device 100 inside, and the battery device 100 can be provided at the bottom, head or tail of the vehicle 1000. The battery device 100 can be used to power the vehicle 1000, for example, the battery device 100 can be used as an operating power source of the vehicle 1000.

[0106] The vehicle 1000 may further include a controller 200 and a motor 300 , wherein the controller 200 is used to control the battery device 100 to supply power to the motor 300 , for example, to meet the power requirements of starting, navigating, and driving the vehicle 1000 .

[0107] In some embodiments of the present application, the battery device 100 can not only serve as an operating power source for the vehicle 1000, but also serve as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0108] Please refer to Figure 2 , Figure 2 This is an exploded view of a battery device 100 provided in some embodiments of the present application. The battery device 100 may include a case 10 and a battery cell 20 . The case 10 is used to accommodate the battery cell 20 .

[0109] Among them, a closed space for accommodating the battery cell 20 is formed inside the box 10. The box 10 can adopt a variety of structures. In some embodiments, the box 10 may include a first box 11 and a second box 12, and the first box 11 and the second box 12 are buckled with each other. The first box 11 and the second box 12 can be in various shapes, such as a cuboid, a cylinder, etc. The first box 11 can be a hollow structure with one side open, and the second box 12 can also be a hollow structure with one side open. The open side of the second box 12 is buckled with the open side of the first box 11 to form a box 10 with a closed space. It is also possible that the first box 11 is a hollow structure with one side open, and the second box 12 is a plate-like structure. The second box 12 is buckled on the open side of the first box 11, so as to form a box 10 with a accommodating space.

[0110] In the battery device 100, there may be one or more battery cells 20. If there are more than one battery cell 20, the battery cells 20 may be connected in series, in parallel, or in a mixed connection. A mixed connection means that the battery cells 20 are connected in series and in parallel. A battery module may be formed by connecting a plurality of battery cells 20 in series, in parallel, or in a mixed connection, and then the plurality of battery modules are connected in series, in parallel, or in a mixed connection to form a whole and accommodated in the box 10. Alternatively, all the battery cells 20 may be directly connected in series, in parallel, or in a mixed connection, and then the whole formed by all the battery cells 20 is accommodated in the box 10.

[0111] In some embodiments, the battery device 100 may further include a busbar component (not shown in the figure), and the multiple battery cells 20 may be electrically connected through the busbar component to achieve series connection, parallel connection, or mixed connection of the multiple battery cells 20. The busbar component may be a metal conductor, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0112] Please refer to Figure 3 , Figure 3 An exploded view of a battery cell 20 provided in some embodiments of the present application. The battery cell 20 may include a housing 21 and an electrode assembly 22 , wherein the electrode assembly 22 is accommodated in the housing 21 .

[0113] In some embodiments, the housing 21 may include a shell 211 and an end cap 212, wherein the shell 211 has an opening 2111, and the end cap 212 closes the opening 2111 of the shell 211. The closing here means covering or closing, which may be sealed or unsealed.

[0114] The shell 211 is a component for accommodating the electrode assembly 22. The shell 211 may be a hollow structure with an opening 2111 formed at one end, or a hollow structure with openings 2111 formed at opposite ends. The shell 211 may be in various shapes, such as a cylindrical shape, a rectangular parallelepiped shape, etc. The material of the shell 211 may be various, such as copper, iron, aluminum, steel, aluminum alloy, etc. The electrode assembly 22 may be partially located in the shell 211, or may be completely located in the shell 211.

[0115] The end cap 212 and the shell 211 together define a receiving space for accommodating the electrode assembly 22 and other components. The end cap 212 can be connected to the shell 211 by welding, crimping, etc. to close the opening 2111 of the shell 211. The shape of the end cap 212 can be adapted to the shape of the shell 211. For example, the shell 211 is a rectangular parallelepiped structure, and the end cap 212 is a rectangular plate structure adapted to the shell 211. For another example, the shell 211 is a cylindrical structure, and the end cap 212 is a circular plate structure adapted to the shell 211. The material of the end cap 212 can also be a variety of materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. The material of the end cap 212 and the shell 211 can be the same or different.

[0116] In the embodiment where the housing 211 forms an opening 2111 at one end, one end cap 212 may be provided accordingly. In the embodiment where the housing 211 forms openings 2111 at two opposite ends, two end caps 212 may be provided accordingly, and the two end caps 212 respectively close the two openings 2111 of the housing 211, and the two end caps 212 and the housing 211 together define a receiving space.

[0117] In some embodiments, the battery cell 20 may further include an electrode terminal 23, which is disposed on the housing 21, and the electrode terminal 23 is used to electrically connect to the tab of the electrode assembly 22 to input or output the electrical energy of the battery cell 20. The electrode terminal 23 may be disposed on the shell 211 of the housing 21, or may be disposed on the end cover 212 of the housing 21. The electrode terminal 23 may be directly connected to the tab, for example, the electrode terminal 23 is welded to the tab. The electrode terminal 23 may also be indirectly connected to the tab, for example, the electrode terminal 23 is indirectly connected to the tab through a current collecting member. The current collecting member may be a metal conductor, for example, copper, iron, aluminum, steel, aluminum alloy, etc.

[0118] As an example, Figure 3As shown, an opening 2111 is formed at one end of the shell 211, and there is one end cap 212 in the shell 21, and one end cap 212 closes one opening 2111 of the shell 211. Two electrode terminals 23 are provided on the end cap 212, and the two electrode terminals 23 are respectively a positive electrode terminal 23 and a negative electrode terminal 23. A positive electrode tab and a negative electrode tab are formed at one end of the electrode assembly 22 facing the end cap 212, and the positive electrode terminal 23 is electrically connected to the positive electrode tab, and the negative electrode terminal 23 is electrically connected to the negative electrode tab.

[0119] like Figure 4 As shown, the embodiment of the present application provides an electrode assembly 22, which is a winding structure. The electrode assembly 22 includes a first pole piece 221, a first isolation film 222, a second pole piece 223 and a second isolation film 224, and the first pole piece 221, the first isolation film 222, the second pole piece 223 and the second isolation film 224 are stacked and wound in sequence to form a winding structure.

[0120] One of the first pole piece 221 and the second pole piece 223 is a positive pole piece, and the other is a negative pole piece.

[0121] The first pole piece 221 includes a first main body 2211 and a first pole ear 2212, and the first pole ear 2212 is connected to one end of the first main body 2211. The second pole piece 223 includes a second main body 2231 and a second pole ear 2232, and the second pole ear 2232 is connected to one end of the second main body 2231; wherein the first isolation membrane 222 and the second isolation membrane 224 are both connected to the edge area of ​​the second main body 2231 close to the first pole ear 2212, and the connection area between the second main body 2231 and the first isolation membrane 222 and the connection area between the second main body 2231 and the second isolation membrane 224 are arranged corresponding to the first pole ear 2212.

[0122] like Figure 5 As shown, the embodiment of the present application provides a method for preparing an electrode assembly 22, and the method for preparing the electrode assembly 22 includes: Step S100: providing a first pole piece 221, a first isolation film 222, a second pole piece 223 and a second isolation film 224; the first pole piece 221 includes a first body 2211 and a first pole ear 2212, the first pole ear 2212 is connected to one end of the first body 2211, the second pole piece 223 includes a second body 2231 and a second pole ear 2232, the second pole ear 2232 is connected to one end of the second body 2231; Step S200: stacking the first pole piece 221, the first isolation film 222, the second pole piece 223 and the second isolation film 224 in sequence; Step S300: connecting the first isolation film 222 and the second isolation film 224 to the edge area of ​​the second body 2231 close to the first electrode tab 2212; Step S400 : Winding the first pole piece 221 , the first isolation film 222 , the second pole piece 223 and the second isolation film 224 to form the electrode assembly 22 , so that the connection area between the second body 2231 and the first isolation film 222 and the connection area between the second body 2231 and the second isolation film 224 are arranged corresponding to the first pole ear 2212 .

[0123] In step S100, the first electrode 221, the first isolation film 222, the second electrode 223 and the second isolation film 224 can be provided by the electrode conveying mechanism 2100 and the isolation film conveying mechanism respectively. There can be two electrode conveying mechanisms 2100, and the two electrode conveying mechanisms 2100 are used to provide the first electrode 221 and the second electrode 223 respectively. There can be two isolation film conveying mechanisms, and the two isolation film conveying mechanisms are used to convey the first isolation film 222 and the second isolation film 224 respectively.

[0124] Figure 6 , a schematic diagram of a pole piece conveying mechanism 2100 is shown. The pole piece conveying mechanism 2100 includes a plurality of conveying rollers 2110 arranged at intervals, and the corresponding pole pieces are wound around the conveying rollers 2110 . Figure 6 Schematic diagram of the electrode sheet conveying mechanism 2100 for conveying the second electrode sheet 223 is shown in FIG.

[0125] The first electrode sheet 221 includes a first current collector 2213 and a first active material layer 2214. The first current collector 2213 is provided with the first active material layer 2214 on at least one side along the thickness direction thereof. The first electrode tab 2212 protrudes from one end of the first current collector 2213 along the width direction of the first electrode sheet 221. Figure 7 As shown, the first current collector 2213 and the first active material layer 2214 together form the first body 2211 of the first electrode 221. The first electrode tab 2212 and the first current collector 2213 can be connected as a whole by welding, conductive adhesive connection, etc. The first electrode tab 2212 and the first current collector 2213 can also be integrally formed. The first electrode 221 can be a positive electrode or a negative electrode. If the first electrode 221 is a positive electrode, such as Figure 8 As shown, in some embodiments, the first current collector 2213 includes a first region 2213a provided with a first active material layer 2214 and a second region 2213b not provided with the first active material layer 2214, and along the width direction of the first pole piece 221, the second region 2213b protrudes from the first active material layer 2214, the first pole piece 221 also includes a first insulating layer 2215, and the second region 2213b is provided with the first insulating layer 2215 on at least one side along the thickness direction thereof, and the first current collector 2213, the first active material layer 2214 and the first insulating layer 2215 together form the first main body 2211.

[0126] The second pole piece 223 includes a second current collector 2233 and a second active material layer 2234. The second current collector 2233 is provided with the second active material layer 2234 on at least one side along the thickness direction thereof. The second pole tab 2232 protrudes from one end of the second current collector 2233 along the width direction of the second pole piece 223. Fig. 9 As shown, the second current collector 2233 and the second active material layer 2234 together form the second body 2231 of the second pole piece 223. The second pole tab 2232 and the second current collector 2233 can be connected as a whole by welding connection, conductive adhesive connection, etc. The second pole tab 2232 and the second current collector 2233 can also be integrally formed.

[0127] The second electrode 223 can be a positive electrode or a negative electrode. Fig.10 As shown, in some embodiments, the second current collector 2233 includes a third region 2233a provided with a second active material layer 2234 and a fourth region 2233b not provided with the second active material layer 2234, and along the width direction of the second pole piece 223, the fourth region 2233b protrudes from the second active material layer 2234, the second pole piece 223 also includes a second insulating layer 2235, and the fourth region 2233b is provided with a second insulating layer 2235 on at least one side along its thickness direction, and the second current collector 2233, the second active material layer 2234 and the second insulating layer 2235 together form a second main body 2231.

[0128] The width direction of the first pole sheet 221 and the width direction of the second pole sheet 223 are parallel to the extending direction of the winding axis of the electrode assembly 22 .

[0129] The first electrode tab 2212 and the second electrode tab 2232 may be located at the same end of the electrode assembly 22 , or at two opposite ends of the electrode assembly 22 .

[0130] The first isolation film 222 and the second isolation film 224 insulate and separate the first pole piece 221 and the second pole piece 223 . After winding, the first pole piece 221 has the first isolation film 222 and the second isolation film 224 on both sides, and the second pole piece 223 has the first isolation film 222 and the second isolation film 224 on both sides.

[0131] The edge region of the second body 2231 close to the first pole ear 2212 refers to the region defined by a distance in the direction away from the first pole ear 2212 at one end of the second body 2231 close to the first pole ear 2212 in the width direction of the second pole piece 223. Exemplarily, along the width direction of the second pole piece 223, the size of the second body 2231 is a, the end of the second body 2231 close to the first pole ear 2212 is the first end 22311, and the region away from the first end 22311 is the edge region of the second body 2231 close to the first pole ear 2212, b≤a. Exemplarily, b=a / 3.

[0132] Step S400 can be performed before step S300 or after step S300, that is, after the first pole piece 221, the first isolation film 222, the second isolation film 224 and the second pole piece 223 are wound to form the electrode assembly 22, the first isolation film 222 and the second isolation film 224 are connected to the edge area of ​​the second body 2231 near the first pole ear 2212. Alternatively, after the first isolation film 222 and the second isolation film 224 are connected to the edge area of ​​the second body 2231 near the first pole ear 2212, the first pole piece 221, the first isolation film 222, the second isolation film 224 and the second pole piece 223 are wound to form the electrode assembly 22.

[0133] One end of the first pole tab 2212 connected to the first body 2211 is the first pole tab root 22121. Figure 4 , Figure 7 , Figure 8 As shown, in step S400, after the first pole piece 221, the first isolation film 222, the second isolation film 224 and the second pole piece 223 are wound to form the electrode assembly 22, the connection area between the second body 2231 and the first isolation film 222 and the connection area between the second body 2231 and the second isolation film 224 are arranged corresponding to the first pole ear 2212, which means that in the projection plane perpendicular to the winding axis direction of the electrode assembly 22, the orthographic projection of the connection area between the second body 2231 and the first isolation film 222 and the connection area between the second body 2231 and the second The orthographic projection of the connection area of ​​the isolation film 224 and the orthographic projection of the first pole ear root 22121 are stacked along the thickness direction of the electrode assembly 22. When observed along the thickness direction of the electrode assembly 22, the orthographic projection of the connection area between the second body 2231 and the first isolation film 222, the orthographic projection of the connection area between the second body 2231 and the second isolation film 224 in the projection plane perpendicular to the winding axis direction of the electrode assembly 22, and the orthographic projection of the first pole ear root 22121 in the projection plane perpendicular to the winding axis direction of the electrode assembly 22 at least partially overlap. Figure 4Q1 is the connection area between the second body 2231 and the first isolation film 222 and the connection area between the second body 2231 and the second isolation film 224 , and Q2 is the connection area between the second body 2231 and the first isolation film 222 and the connection area between the second body 2231 and the second isolation film 224 .

[0134] The first isolation film 222 and the second isolation film 224 are connected to the edge area of ​​the second body 2231 near the first pole ear 2212, and the first pole piece 221, the first isolation film 222, the second pole piece 223 and the second isolation film 224 are wound to form the electrode assembly 22, so that the connection area between the second body 2231 and the first isolation film 222 and the connection area between the second body 2231 and the second isolation film 224 are arranged corresponding to the first pole ear 2212, and the second body 2231 and the first isolation film 222 are arranged at the corresponding position of the first pole ear 2212. There is no gap between the electrode assembly 2211 and the second isolation film 224, or the gap is insufficient for the first pole ear 2212 to be inserted. Therefore, the risk of the first pole ear 2212 being redundantly inserted between the second body 2231 and the first isolation film 222 and between the second body 2231 and the second isolation film 224 is reduced, thereby reducing the risk of the first pole ear 2212 and the second body 2231 contacting to cause a short circuit, reducing the risk of thermal runaway of the battery cell 20 having the electrode assembly 22, improving the reliability of the battery cell 20, and extending the service life of the battery cell 20 having the electrode assembly 22.

[0135] There are many ways to connect the first isolation film 222 and the second body 2231, and there are many ways to connect the second isolation film 224 and the second body 2231, such as Fig.11 As shown, in some embodiments, step S300 includes: Step S310 : bonding the first isolation film 222 and the second isolation film 224 to the edge region of the second body 2231 close to the first electrode tab 2212 .

[0136] It can be understood that the first isolation film 222 and the edge area of ​​the second body 2231 near the first pole tab 2212 are connected by adhesive connection, and the second isolation film 224 and the edge area of ​​the second body 2231 near the first pole tab 2212 are connected by adhesive connection.

[0137] The first isolation membrane 222 and the second isolation membrane 224 are both bonded to the edge area of ​​the second body 2231 near the first pole ear 2212, making it more convenient to connect the first isolation membrane 222 and the second body 2231, and to connect the second isolation membrane 224 and the second body 2231. The connection stability between the first isolation membrane 222 and the second body 2231, and between the second isolation membrane 224 and the second body 2231 is better.

[0138] like Fig.12 As shown, in some other embodiments, before step S200, the method for preparing the electrode assembly 22 further includes: Step S500: a first cured adhesive layer is disposed on both sides of the edge region of the second body 2231 close to the first electrode tab 2212 ; Step S310 includes: Step S311: heating the first curing adhesive layer into an adhesive; Step S312 : bonding the adhesive on both sides of the edge region of the second body 2231 close to the first electrode tab 2212 to the first isolation film 222 and the second isolation film 224 respectively.

[0139] The two sides of the edge region of the second body 2231 close to the first electrode tab 2212 refer to the two sides of the edge region of the second body 2231 close to the first electrode tab 2212 in the thickness direction thereof.

[0140] The first cured adhesive layer can be formed by solidifying a fluid slurry. The first cured adhesive layer can also be formed by solidifying a gel-like slurry. After heating the first cured adhesive layer, the first cured adhesive layer melts to form a viscous adhesive.

[0141] The adhesive may be a thermoplastic adhesive, which includes, but is not limited to, cellulose esters, vinyl polymers (polyvinyl acetate, polyvinyl alcohol, perchlorethylene, polyisobutylene, etc.), polyesters, polyethers, polyamides, polyacrylates, a-cyanoacrylates, polyvinyl acetals, ethylene-vinyl acetate copolymers, and the like.

[0142] The adhesive can also be a synthetic rubber type or rubber resin type adhesive, such as chloroprene rubber, styrene-butadiene rubber, butyl rubber, sodium-butadiene rubber, isoprene rubber, polysulfide rubber, polyurethane rubber, chlorosulfonated polyethylene elastomer, silicone rubber, phenolic-nitrile rubber, phenolic-chloroprene rubber, phenolic-polyurethane rubber, epoxy-nitrile rubber, epoxy-polysulfide rubber, etc.

[0143] The adhesive may also be a thermosetting adhesive. Thermosetting adhesives include, but are not limited to, epoxy resins, phenolic resins, urea-formaldehyde resins, cyanuric-formaldehyde resins, silicone resins, furan resins, unsaturated polyesters, acrylic resins, polyimides, polybenzimidazoles, phenolic-polyvinyl acetals, phenolic-polyamides, phenolic-epoxy resins, epoxy-polyamides, and the like.

[0144] The first cured adhesive layer can be heated into an adhesive by infrared heating. Of course, other methods can also be used to heat the first cured adhesive layer into an adhesive, such as resistance heating.

[0145] Along the width direction of the second electrode piece 223, the size of the first cured adhesive layer may be the same as the size of the edge area of ​​the second body 2231 near the first electrode tab 2212. The size of the first cured adhesive layer may be smaller than the size of the edge area of ​​the second body 2231 near the first electrode tab 2212.

[0146] In the embodiment where the size of the first cured adhesive layer is smaller than the size of the edge region of the second body 2231 near the first pole ear 2212 along the width direction of the second pole piece 223, the edge of the first cured adhesive layer near the first pole ear 2212 can be flush with the edge of the second body 2231 near the first pole ear 2212, so as to further reduce the insertion of the first pole ear 2212 between the second body 2231 and the first isolation film 222 and between the second body 2231 and the first isolation film 222. In the embodiment where the size of the first cured adhesive layer is smaller than the size of the edge region of the second body 2231 near the first pole ear 2212 along the width direction of the second pole piece 223, the edge of the first cured adhesive layer near the first pole ear 2212 is farther away from the first pole ear 2212 than the edge of the second body 2231 near the first pole ear 2212, which can reduce the difficulty of setting the first cured adhesive layer.

[0147] By arranging a first cured adhesive layer in the edge area of ​​the second main body 2231 near the first pole ear 2212 before stacking the first pole piece 221, the first isolation film 222, the second pole piece 223 and the second isolation film 224 in sequence, the first cured adhesive layer does not have fluidity. Therefore, during the transportation of the second pole piece 223, the first cured adhesive layer will not flow along the transportation direction of the second pole piece 223 or the risk of the first cured adhesive layer detaching from the second main body 2231 is low, which facilitates the bonding of the first isolation film 222 and the second isolation film 224 to the second main body 2231, and is beneficial to achieving stable bonding between the first isolation film 222 and the second main body 2231 and between the first isolation film 222 and the second main body 2231, thereby facilitating improving the quality of the electrode assembly 22.

[0148] like Fig.13 As shown, in some embodiments, step S500 includes: Step S510: coating slurry on both sides of the edge area of ​​the second body 2231 close to the first electrode tab 2212; Step S520 : drying the slurry so that the slurry forms a first cured adhesive layer on both sides of the edge region of the second body 2231 close to the first electrode tab 2212 .

[0149] The slurry has certain fluidity and viscosity. The slurry is first applied to both sides of the edge area of ​​the second body 2231 close to the first pole ear 2212, and then the slurry on both sides of the edge area of ​​the second body 2231 close to the first pole ear 2212 is dried, so that the two layers of the slurry in the edge area of ​​the second body 2231 close to the first pole ear 2212 form a first cured adhesive layer.

[0150] The slurry is applied to both sides of the edge area of ​​the second body 2231 near the first pole ear 2212. The process is relatively simple to implement. The slurry is then dried to form a first cured adhesive layer. After the slurry is dried and cured, it has no viscosity. During the transportation of the second pole piece 223, the cured slurry (first cured adhesive layer) is not easy to be contaminated by bonding with other substances. The risk of the first cured adhesive layer being contaminated and reducing the bonding performance is low. The cured slurry (first cured adhesive layer) has no fluidity. During the transportation of the second pole piece 223, the first cured adhesive layer will not flow along the transportation direction of the second pole piece 223 or other directions, or the risk of the first cured adhesive layer being separated from the second body 2231 is low, which facilitates the bonding of the first isolation film 222 and the second isolation film 224 with the second body 2231, and is conducive to achieving stable bonding between the first isolation film 222 and the second body 2231, and between the first isolation film 222 and the second body 2231, thereby facilitating the improvement of the quality of the electrode assembly 22.

[0151] like Fig.14 As shown, in some embodiments, step S510 includes: Step S511: coating slurry on one side of the edge area of ​​the second body 2231 close to the first electrode tab 2212; Step S512 : coating slurry on the other side of the edge region of the second body 2231 close to the first electrode tab 2212 .

[0152] like Figure 6As shown, the electrode assembly manufacturing equipment 2000 includes a first coating mechanism 2200 and a second coating mechanism 2300, and the second coating mechanism 2300 is arranged downstream of the first coating mechanism 2200. The first coating mechanism 2200 is used to apply slurry to one side of the edge area of ​​the second body 2231 close to the first pole ear 2212, and the second coating mechanism 2300 is used to apply slurry to the other side of the edge area of ​​the second body 2231 close to the first pole ear 2212. When the first coating mechanism 2200 applies slurry to one side of the edge area of ​​the second body 2231 close to the first pole ear 2212, the side of the edge area of ​​the second body 2231 close to the first pole ear 2212 faces upward and faces the first coating mechanism 2200, so that the slurry applied on the side of the edge area of ​​the second body 2231 close to the first pole ear 2212 by the first coating mechanism 2200 is not easy to flow and drip before solidification. After the first coating mechanism 2200 completes coating, the position of the second pole piece 223 coated with the slurry is transported to the second coating mechanism 2300 under the transport of the first transport mechanism, with the side coated with the slurry facing downward, and the side to be coated by the second coating mechanism 2300 facing upward and facing the second coating mechanism 2300, so that the slurry coated on one side of the edge area of ​​the second body 2231 close to the first pole ear 2212 by the first coating mechanism 2200 is not easy to flow and drip before solidification.

[0153] The electrode assembly manufacturing equipment 2000 further includes a first drying mechanism 2400 and a second drying mechanism 2500. The first drying mechanism 2400 is disposed downstream of the first coating mechanism 2200 and upstream of the second coating mechanism 2300, and is used to dry the slurry coated by the first coating mechanism 2200 on one side of the edge region of the second body 2231 close to the first pole tab 2212, so as to form a first cured adhesive layer.

[0154] The second drying structure is arranged downstream of the second coating mechanism 2300, and the second drying mechanism 2500 is used to dry the slurry coated by the second coating mechanism 2300 on the other side of the edge region of the second body 2231 close to the first pole ear 2212, so as to form a first cured adhesive layer. The first drying mechanism 2400 is arranged downstream of the first coating mechanism 2200 and upstream of the second coating mechanism 2300, and the processing of the second pole piece 223 by the first drying mechanism 2400 is located after the processing of the second pole piece 223 by the first coating mechanism 2200 and before the processing of the second pole piece 223 by the second coating mechanism 2300.

[0155] It should be noted that the "upstream" and "downstream" described in the embodiments of the present application do not refer to the spatial position relationship between the mechanisms, but refer to the order of the processes. The second coating mechanism 2300 is located downstream of the first coating mechanism 2200, and the processing of the second pole piece 223 by the first coating mechanism 2200 is located before the processing of the second pole piece 223 by the second coating mechanism 2300.

[0156] The first coating mechanism 2200 first applies slurry to one side of the edge area of ​​the second body 2231 close to the first pole ear 2212, and the first conveying mechanism conveys the position where the second pole piece 223 is coated with slurry by the first coating mechanism 2200 to the first drying mechanism 2400, and dries it by the first drying mechanism 2400 to form a first cured adhesive layer.

[0157] The second coating mechanism 2300 then coats the slurry on the other side of the edge area of ​​the second body 2231 close to the first pole ear 2212, and the first conveying mechanism conveys the position where the second pole piece 223 is coated with the slurry by the second coating mechanism 2300 to the second drying mechanism 2500, and dries it by the second drying mechanism 2500 to form a first cured adhesive layer.

[0158] The first coating mechanism 2200 and the second coating mechanism 2300 can simultaneously coat the second body 2231 with slurry.

[0159] The slurry is applied on one side of the edge area of ​​the second body 2231 close to the first pole ear 2212, and then the slurry is applied on the other side of the edge area of ​​the second body 2231 close to the first pole ear 2212. The slurry is applied on both sides of the edge area of ​​the second body 2231 close to the first pole ear 2212 in sequence, which is beneficial to improve the coating quality.

[0160] like Fig.15 As shown, in some embodiments, step S511 includes: Step S5111: coating the slurry at intervals along the length direction of the second body 2231 on one side of the edge region of the second body 2231 close to the first electrode tab 2212 ; Step S512 includes: Step S5121 : coating the slurry at intervals along the length direction of the second body 2231 on the other side of the edge region of the second body 2231 close to the first electrode tab 2212 .

[0161] The slurry is applied at intervals along the length direction of the second body 2231 on one side of the edge region of the second body 2231 close to the first pole ear 2212, and a plurality of slurry application positions may be arranged at intervals along the length direction of the second body 2231 on one side of the edge region of the second body 2231 close to the first pole ear 2212. The first coating mechanism 2200 may work intermittently to achieve the slurry application at intervals along the length direction of the second body 2231 on one side of the edge region of the second body 2231 close to the first pole ear 2212.

[0162] The slurry is applied at intervals along the length direction of the second body 2231 on the other side of the edge region of the second body 2231 close to the first pole ear 2212, and a plurality of slurry application positions may be arranged at intervals along the length direction of the second body 2231 on the other side of the edge region of the second body 2231 close to the first pole ear 2212. The second coating mechanism 2300 may work intermittently to achieve the slurry application at intervals along the length direction of the second body 2231 on the other side of the edge region of the second body 2231 close to the first pole ear 2212.

[0163] The slurry is coated at intervals along the length direction of the second body 2231 on both sides of the edge area of ​​the second body 2231 close to the first pole ear 2212, so that a smaller area of ​​the second body 2231 is covered by the slurry, which is beneficial to the wetting of the second pole piece 223, thereby facilitating the improvement of the cycle performance and life of the battery cell 20.

[0164] like Fig.16 As shown, in some other embodiments, step S511 includes: Step S5111: Continuously apply slurry on one side of the edge region of the second body 2231 close to the first electrode tab 2212 along the length direction of the second body 2231 ; Step S512 includes: Step S5121 : continuously coating the slurry along the length direction of the second body 2231 on the other side of the edge region of the second body 2231 close to the first electrode tab 2212 .

[0165] The slurry is continuously coated on one side of the edge region of the second body 2231 close to the first pole tab 2212 along the length direction of the second body 2231, and the size of the slurry on one side of the edge region of the second body 2231 close to the first pole tab 2212 can be the same as the size of the second body 2231 along its length direction. The first coating mechanism 2200 can be operated continuously to achieve continuous coating of the slurry on one side of the edge region of the second body 2231 close to the first pole tab 2212 along the length direction of the second body 2231.

[0166] The slurry is continuously applied on the other side of the edge region of the second body 2231 close to the first pole tab 2212 along the length direction of the second body 2231, and the size of the slurry on the other side of the edge region of the second body 2231 close to the first pole tab 2212 can be the same as the size of the second body 2231 along its length direction. The second coating mechanism 2300 can be continuously operated to achieve continuous coating of the slurry on the side of the edge region of the second body 2231 close to the first pole tab 2212 along the length direction of the second body 2231.

[0167] The slurry is continuously applied on both sides of the edge area of ​​the second body 2231 close to the first pole ear 2212 along the length direction of the second body 2231, which makes coating more convenient and allows a larger area of ​​the second body 2231 to be covered by the slurry, which is beneficial to increasing the bonding area between the second body 2231 and the first isolation membrane 222, and between the second body 2231 and the second isolation membrane 224. It not only provides bonding stability, but also reduces the risk of the first pole ear 2212 being inserted between the second body 2231 and the first isolation membrane 222, and between the second body 2231 and the second isolation membrane 224 after being misplaced.

[0168] like Fig.17 As shown, in some embodiments, after step S520, step S400 includes: Step S410: Winding the first electrode sheet 221, the first isolation film 222, the second electrode sheet 223 and the second isolation film 224 to form the electrode assembly 22; The step S311 includes: Step S3111: heating the electrode assembly 22 to heat the first curing adhesive layer into an adhesive; The step S312 includes: Step S3121 : hot-pressing the electrode assembly 22 so that the adhesive on both sides of the edge region of the second body 2231 close to the first electrode tab 2212 is bonded to the first isolation film 222 and the second isolation film 224 respectively.

[0169] After drying the slurry coated on both sides of the edge area of ​​the second body 2231 near the first pole ear 2212 to form a first cured adhesive layer, the first pole piece 221, the first isolation film 222, the second pole piece 223 and the second isolation film 224 are wound to form the electrode assembly 22, and the electrode assembly 22 is heated to heat the first cured adhesive layer into an adhesive. Then, the electrode assembly 22 is hot-pressed to make the adhesive on both sides of the edge area of ​​the second body 2231 near the first pole ear 2212 bond to the first isolation film 222 and the second isolation film 224 respectively, so that the edge area of ​​the second body 2231 near the first pole ear 2212 is bonded to the first isolation film 222 by the adhesive, and the edge area of ​​the second body 2231 near the first pole ear 2212 is bonded to the second isolation film 224 by the adhesive.

[0170] Since the second electrode piece 223 is relatively long, after the electrode assembly 22 is formed by winding the first electrode piece 221, the first isolation film 222, the second electrode piece 223 and the second isolation film 224, the electrode assembly 22 is heated to heat the first cured adhesive layer into an adhesive. In this way, when the electrode assembly 22 is heated, the heat can be more concentrated to heat the electrode assembly 22, which can reduce energy consumption. After the first cured adhesive layer is heated to form an adhesive, the electrode assembly 22 is hot-pressed to make the adhesive on both sides of the edge area of ​​the second body 2231 close to the first pole ear 2212 bonded to the first isolation film 222 and the second isolation film 224 respectively. Not only does it achieve the bonding of the first isolation film 222 and the second isolation film 224 to the second body 2231, it is also beneficial to further forming the electrode assembly 22, and the preparation process of the electrode assembly 22 is optimized.

[0171] like Fig.18 As shown, in some embodiments, the method for preparing the electrode assembly 22 further includes: Step S600: connecting the first isolation film 222 and the second isolation film 224 to the edge area of ​​the first body 2211 close to the second electrode tab 2232; The step S400 includes: Step S420: Wind the first pole piece 221 , the first isolation film 222 , the second pole piece 223 and the second isolation film 224 to form the electrode assembly 22 , so that the connection area between the first body 2211 and the first isolation film 222 and the connection area between the first body 2211 and the second isolation film 224 are arranged corresponding to the second pole ear 2232 .

[0172] The edge region of the first body 2211 close to the second pole ear 2232 refers to a region defined by a distance in a direction away from the second pole ear 2232 at one end of the first body 2211 close to the second pole ear 2232 in the width direction of the first pole piece 221. Exemplarily, along the width direction of the first pole piece 221, the size of the first body 2211 is g, the end of the first body 2211 close to the second pole ear 2232 is the third end 22111, and the region away from the third end 22111 is the edge region of the first body 2211 close to the second pole ear 2232, k≤g. Exemplarily, g=k / 3.

[0173] Step S420 can be performed before step S600, that is, after the first electrode sheet 221, the first isolation membrane 222, the second isolation membrane 224 and the second electrode sheet 223 are wound to form the electrode assembly 22, the first isolation membrane 222 and the second isolation membrane 224 are connected to the edge area of ​​the first body 2211 near the second electrode ear 2232.

[0174] Step S300 and step S600 may be performed after step S400. Step S410 and step S420 may be the same execution step.

[0175] In the embodiment where step S400 is performed before step S300, step S600 can be performed after step S420, that is, after the first isolation membrane 222 and the second isolation membrane 224 are connected to the edge area of ​​the first body 2211 close to the second pole ear 2232, the first pole piece 221, the first isolation membrane 222, the second isolation membrane 224 and the second pole piece 223 are wound to form the electrode assembly 22, so as to facilitate the winding to form the electrode assembly 22.

[0176] One end of the second pole ear 2232 connected to the second body 2231 is the second pole ear root 22321. Figure 4 , Fig. 9 , Fig.10As shown, in step S400, after the first pole piece 221, the first isolation film 222, the second isolation film 224 and the second pole piece 223 are wound to form the electrode assembly 22, the connection area of ​​the first body 2211 and the first isolation film 222 and the connection area of ​​the first body 2211 and the second isolation film 224 are arranged corresponding to the second pole ear 2232, which means that in the projection plane perpendicular to the winding axis direction of the electrode assembly 22, the orthographic projection of the connection area of ​​the first body 2211 and the first isolation film 222 and the connection area of ​​the first body 2211 and the second The orthographic projection of the connection area of ​​the isolation film 224 and the orthographic projection of the second pole ear root 22321 are stacked along the thickness direction of the electrode assembly 22. When observed along the thickness direction of the electrode assembly 22, the orthographic projection of the connection area between the first body 2211 and the first isolation film 222, the orthographic projection of the connection area between the first body 2211 and the second isolation film 224 in the projection plane perpendicular to the winding axis direction of the electrode assembly 22, and the orthographic projection of the second pole ear root 22321 in the projection plane perpendicular to the winding axis direction of the electrode assembly 22 at least partially overlap. Figure 4 Q3 is the connection area between the first body 2211 and the first isolation film 222 and the connection area between the first body 2211 and the second isolation film 224 ; Q4 is the connection area between the first body 2211 and the first isolation film 222 and the connection area between the first body 2211 and the second isolation film 224 .

[0177] The first isolation film 222 and the second isolation film 224 are both connected to the edge area of ​​the first body 2211 near the second pole ear 2232, and the first pole piece 221, the first isolation film 222, the second pole piece 223 and the second isolation film 224 are wound to form the electrode assembly 22, so that the connection area between the first body 2211 and the first isolation film 222 and the connection area between the first body 2211 and the second isolation film 224 are arranged corresponding to the second pole ear 2232. At the corresponding position of the second pole ear 2232, the first body 2211 and the first isolation film 222 are connected. There is no gap between the first body 2211 and the first isolation membrane 224, or the gap is insufficient for the second pole ear 2232 to be inserted. Therefore, the risk of redundant insertion of the second pole ear 2232 between the first body 2211 and the first isolation membrane 222 and between the first body 2211 and the second isolation membrane 224 is reduced, thereby reducing the risk of short circuit caused by contact between the second pole ear 2232 and the first body 2211, reducing the risk of thermal runaway of the battery cell 20 equipped with the electrode assembly 22, and improving the reliability of the battery cell 20.

[0178] There are many ways to connect the first isolation film 222 to the first body 2211, and there are many ways to connect the second isolation film 224 to the first body 2211, such as Fig.18 , Fig.19 As shown, in some embodiments, step S600 includes: Step S610 : bonding the first isolation film 222 and the second isolation film 224 to the edge region of the first body 2211 close to the second electrode tab 2232 .

[0179] It can be understood that the first isolation film 222 is connected to the edge area of ​​the first body 2211 near the second pole ear 2232 by adhesive connection, and the second isolation film 224 is connected to the edge area of ​​the first body 2211 near the second pole ear 2232 by adhesive connection.

[0180] The first isolation membrane 222 and the second isolation membrane 224 are both bonded to the edge area of ​​the first body 2211 near the second pole ear 2232, making it more convenient to connect the first isolation membrane 222 and the first body 2211, and to connect the second isolation membrane 224 and the first body 2211, and the connection stability between the first isolation membrane 222 and the first body 2211, and between the second isolation membrane 224 and the first body 2211 is better.

[0181] like Fig.18 , Fig.19 As shown, in some embodiments, before step S200, the method for preparing the electrode assembly 22 further includes: Step S800: a second cured adhesive layer is disposed on both sides of the edge area of ​​the first body 2211 close to the second electrode tab 2232; Step S610 includes: Step S611: heating the second curing adhesive layer to form an adhesive; Step S612 : bonding the adhesive on both sides of the edge region of the first body 2211 close to the second electrode tab 2232 to the first isolation film 222 and the second isolation film 224 respectively.

[0182] The two sides of the edge region of the first body 2211 close to the second electrode tab 2232 refer to the two sides of the edge region of the first body 2211 close to the second electrode tab 2232 in the thickness direction thereof.

[0183] The second cured adhesive layer can be formed by solidifying a fluid slurry. The second cured adhesive layer can also be formed by solidifying a gel-like slurry. After heating the second cured adhesive layer, the second cured adhesive layer melts to form a viscous adhesive.

[0184] The material of the second curing adhesive layer may be the same as or different from that of the first curing adhesive layer.

[0185] The second cured adhesive layer can be heated into an adhesive by infrared heating. Of course, other methods can also be used to heat the second cured adhesive layer into an adhesive, such as resistance heating.

[0186] Along the width direction of the first electrode piece 221, the size of the second cured adhesive layer may be the same as the size of the edge area of ​​the first body 2211 near the second electrode tab 2232. The size of the second cured adhesive layer may be smaller than the size of the edge area of ​​the first body 2211 near the second electrode tab 2232.

[0187] In the embodiment where the size of the second cured adhesive layer is smaller than the size of the edge region of the first body 2211 near the first pole ear 2212 along the width direction of the first pole piece 221, the edge of the second cured adhesive layer near the second pole ear 2232 may be flush with the edge of the first body 2211 near the second pole ear 2232, so as to further reduce the insertion of the second pole ear 2232 between the first body 2211 and the first isolation film 222 and between the first body 2211 and the first isolation film 222. In the embodiment where the size of the second cured adhesive layer is smaller than the size of the edge region of the first body 2211 near the second pole ear 2232 along the width direction of the first pole piece 221, the edge of the second cured adhesive layer near the second pole ear 2232 is farther away from the second pole ear 2232 than the edge of the first body 2211 near the second pole ear 2232, which can reduce the difficulty of setting the second cured adhesive layer.

[0188] By arranging a second cured adhesive layer in the edge area of ​​the first main body 2211 near the second pole ear 2232 before stacking the first pole piece 221, the first isolation film 222, the second pole piece 223 and the second isolation film 224 in sequence, the second cured adhesive layer does not have fluidity. Therefore, during the transportation of the first pole piece 221, the second cured adhesive layer will not flow along the transportation direction of the first pole piece 221 or the risk of the second cured adhesive layer detaching from the first main body 2211 is low, which facilitates the bonding of the first isolation film 222 and the second isolation film 224 to the first main body 2211, and is beneficial to achieving stable bonding between the first isolation film 222 and the first main body 2211 and between the first isolation film 222 and the first main body 2211, thereby facilitating improving the quality of the electrode assembly 22.

[0189] like Fig.18 As shown, in some embodiments, step S800 includes: Step S810: coating slurry on both sides of the edge area of ​​the first body 2211 close to the second electrode tab 2232; Step S820 : drying the slurry so that the slurry forms a second cured adhesive layer on both sides of the edge region of the first body 2211 close to the second electrode tab 2232 .

[0190] First, apply slurry on both sides of the edge area of ​​the first body 2211 close to the second pole ear 2232, and then dry the slurry on both sides of the edge area of ​​the first body 2211 close to the second pole ear 2232, so that the two layers of slurry in the edge area of ​​the first body 2211 close to the second pole ear 2232 form second cured adhesive layers respectively.

[0191] The slurry is applied to both sides of the edge area of ​​the first body 2211 near the second pole ear 2232. The process is relatively simple to implement. The slurry is then dried to form a second cured adhesive layer. After the slurry is dried and cured, it has no viscosity. During the transportation of the first pole piece 221, the cured slurry (second cured adhesive layer) is not easy to be contaminated by bonding other substances, and the risk of the second cured adhesive layer being contaminated and reduced in bonding performance is low. The cured slurry (second cured adhesive layer) has no fluidity. During the transportation of the first pole piece 221, the second cured adhesive layer will not flow along the transportation direction of the first pole piece 221 or the risk of the second cured adhesive layer being separated from the first body 2211 is low, which facilitates the bonding of the first isolation film 222 and the second isolation film 224 to the first body 2211, and is conducive to achieving stable bonding between the first isolation film 222 and the first body 2211, and between the first isolation film 222 and the first body 2211, thereby facilitating the improvement of the quality of the electrode assembly 22.

[0192] like Fig.18 , Fig. 20 In some embodiments, step S810 includes: Step S811: coating slurry on one side of the edge area of ​​the first body 2211 close to the second electrode tab 2232; Step S812 : applying slurry on the other side of the edge region of the first body 2211 close to the second electrode tab 2232 .

[0193] The electrode assembly manufacturing equipment 2000 includes a third coating mechanism (not shown in the figure) and a fourth coating mechanism (not shown in the figure), and the fourth coating mechanism is arranged downstream of the third coating mechanism. The third coating mechanism is used to apply slurry to one side of the edge area of ​​the first body 2211 close to the second pole ear 2232, and the fourth coating mechanism is used to apply slurry to the other side of the edge area of ​​the first body 2211 close to the second pole ear 2232. When the third coating mechanism applies slurry to one side of the edge area of ​​the first body 2211 close to the second pole ear 2232, the side of the edge area of ​​the first body 2211 close to the second pole ear 2232 faces upward and faces the third coating mechanism, so that the slurry applied by the third coating mechanism to one side of the edge area of ​​the first body 2211 close to the second pole ear 2232 is not easy to flow and drip before solidification. After the third coating mechanism completes coating, the position of the first pole piece 221 coated with the slurry is transported to the fourth coating mechanism under the transport of the second transport mechanism, with the side coated with the slurry facing downward, and the side to be coated by the fourth coating mechanism facing upward and facing the fourth coating mechanism, so that the slurry coated on one side of the edge area of ​​the first body 2211 close to the second pole ear 2232 by the third coating mechanism is not easy to flow and drip before solidification.

[0194] The electrode assembly manufacturing equipment 2000 further includes a third drying mechanism (not shown in the figure) and a fourth drying mechanism (not shown in the figure). The third drying mechanism is arranged downstream of the third coating mechanism and upstream of the fourth coating mechanism, and is used to dry the slurry coated by the third coating mechanism on one side of the edge area of ​​the fourth body close to the second pole ear 2232, so as to form a second cured adhesive layer.

[0195] The fourth drying structure is arranged downstream of the fourth coating mechanism, and the fourth drying mechanism is used to dry the slurry coated by the fourth coating mechanism on the other side of the edge area of ​​the first body 2211 close to the second pole ear 2232, so as to form a second cured adhesive layer. The third drying mechanism is arranged downstream of the third coating mechanism and upstream of the fourth coating mechanism, and the processing of the first pole piece 221 by the third drying mechanism is located after the processing of the first pole piece 221 by the third coating mechanism and before the processing of the first pole piece 221 by the fourth coating mechanism.

[0196] The third coating mechanism is used to first coat one side of the edge area of ​​the first body 2211 close to the second pole ear 2232 with slurry, and the second conveying mechanism conveys the first pole piece 221 coated with slurry by the first coating mechanism 2200 to the third drying mechanism, and the third drying mechanism dries it to form a second cured adhesive layer.

[0197] The slurry is then applied to the other side of the edge area of ​​the first body 2211 close to the second pole ear 2232 by the fourth coating mechanism, and the second conveying mechanism conveys the position where the first pole piece 221 is coated with the slurry by the fourth coating mechanism to the fourth drying mechanism, and is dried by the fourth drying mechanism to form a second cured adhesive layer.

[0198] The third coating mechanism and the fourth coating mechanism can simultaneously coat the first body 2211 with slurry.

[0199] The slurry is applied on one side of the edge area of ​​the first body 2211 close to the second pole ear 2232, and then the slurry is applied on the other side of the edge area of ​​the first body 2211 close to the second pole ear 2232. The slurry is applied on both sides of the edge area of ​​the first body 2211 close to the second pole ear 2232 in sequence, which is beneficial to improve the coating quality.

[0200] like Fig.18 , Fig. 20 As shown, in some embodiments, step S811 includes: Step S8111: coating the slurry at intervals along the length direction of the first body 2211 on one side of the edge region of the first body 2211 close to the second electrode tab 2232 ; Step S812 includes: Step S8121 : applying the slurry at intervals along the length direction of the first body 2211 on the other side of the edge region of the first body 2211 close to the second electrode tab 2232 .

[0201] The slurry is applied at intervals along the length direction of the first body 2211 on one side of the edge region of the first body 2211 close to the second pole ear 2232, and multiple slurry application positions can be arranged at intervals along the length direction of the first body 2211 on one side of the edge region of the first body 2211 close to the second pole ear 2232. The third coating mechanism can be intermittently operated to achieve the slurry application at intervals along the length direction of the first body 2211 on one side of the edge region of the first body 2211 close to the second pole ear 2232. The slurry application position is located between two adjacent second pole ears 2232 to avoid the slurry and the second pole ear 2232 from interfering and affecting the input or output of electric energy of the second pole ear 2232. Therefore, the electrode assembly manufacturing equipment 2000 may also include a pole ear detection mechanism 2600, which is used to detect the position of the pole ear on the pole piece, such as detecting the position of the second pole ear 2232 of the second pole piece 223, so that the slurry application positions of the first coating mechanism 2200 and the second coating mechanism 2300 can avoid the second pole ear 2232. Each pole piece conveying mechanism 2100 may be provided with two pole lug detection mechanisms 2600, one pole lug detection mechanism 2600 is located upstream of the first coating mechanism 2200, and is used to detect the position of the pole lug before the first coating mechanism 2200 applies the slurry, and the other pole lug detection mechanism 2600 is located upstream of the second coating mechanism 2300 and downstream of the first drying mechanism 2400, and is used to detect the position of the pole lug before the second coating mechanism 2300 applies the slurry. The pole lug detection mechanism 2600 may have a variety of structures, for example, the pole lug detection mechanism 2600 includes a transmitter and a receiver, the transmitter and the receiver are respectively located on both sides of the pole piece thickness direction, the transmitter is used to emit laser, and the receiver is used to receive the laser emitted by the transmitter. When the pole lug is located in an area outside the transmitter and the receiver, the receiver can receive the laser emitted by the transmitter, when the pole lug moves between the transmitter and the receiver, the laser emitted by the transmitter is blocked by the pole lug, and the receiver cannot receive the laser emitted by the transmitter, and when the receiver fails to receive the laser emitted by the transmitter, it is determined that the pole lug is detected.

[0202] The slurry is applied at intervals along the length direction of the first body 2211 on the other side of the edge region of the first body 2211 close to the second pole ear 2232, and a plurality of slurry application positions may be arranged at intervals along the length direction of the first body 2211 on the other side of the edge region of the first body 2211 close to the second pole ear 2232. The fourth coating mechanism may work intermittently to achieve the slurry application at intervals along the length direction of the first body 2211 on the other side of the edge region of the first body 2211 close to the second pole ear 2232.

[0203] The slurry is coated at intervals along the length direction of the first body 2211 on both sides of the edge area of ​​the first body 2211 close to the second pole ear 2232, so that a smaller area of ​​the first body 2211 is covered by the slurry, which is beneficial to the wetting of the first pole piece 221, thereby facilitating the improvement of the cycle performance and life of the battery cell 20.

[0204] like Fig.18 , Fig.21 As shown, in some other embodiments, step S811 includes: Step S8111: Continuously apply slurry on one side of the edge area of ​​the first body 2211 close to the second electrode tab 2232 along the length direction of the first body 2211; Step S812 includes: Step S8211 : Continuously apply the slurry along the length direction of the first body 2211 on the other side of the edge region of the first body 2211 close to the second electrode tab 2232 .

[0205] The slurry is continuously applied on one side of the edge region of the first body 2211 close to the second pole ear 2232 along the length direction of the first body 2211, and the size of the slurry on the side of the edge region of the first body 2211 close to the second pole ear 2232 can be the same as the size of the first body 2211 along its length direction. The third coating mechanism can be continuously operated to achieve continuous coating of the slurry on one side of the edge region of the first body 2211 close to the second pole ear 2232 along the length direction of the first body 2211.

[0206] The slurry is continuously coated on the other side of the edge region of the first body 2211 close to the second pole ear 2232 along the length direction of the first body 2211, and the size of the slurry on the other side of the edge region of the first body 2211 close to the second pole ear 2232 can be the same as the size of the first body 2211 along its length direction. The fourth coating mechanism can be continuously operated to achieve continuous coating of the slurry on one side of the edge region of the first body 2211 close to the second pole ear 2232 along the length direction of the first body 2211.

[0207] The slurry is continuously applied on both sides of the edge area of ​​the first body 2211 close to the second pole ear 2232 along the length direction of the first body 2211, which makes coating more convenient and allows a larger area of ​​the first body 2211 to be covered by the slurry, which is beneficial to increasing the bonding area between the first body 2211 and the first isolation membrane 222, and between the first body 2211 and the second isolation membrane 224. It not only provides bonding stability, but also reduces the risk of the second pole ear 2232 being inserted between the first body 2211 and the first isolation membrane 222, and between the first body 2211 and the second isolation membrane 224 after being misplaced.

[0208] like Fig.18, Fig. 22 As shown, in some embodiments, after step S820, and after step S420, step S611 includes; Step S6111: heating the electrode assembly 22 to heat the second curing adhesive layer into an adhesive; Step S612 includes: Step S6121 : hot-pressing the electrode assembly 22 so that the adhesive on both sides of the edge region of the first body 2211 close to the second electrode tab 2232 is bonded to the first isolation film 222 and the second isolation film 224 , respectively.

[0209] After drying the slurry coated on both sides of the edge area of ​​the first body 2211 near the second pole ear 2232 to form a second cured adhesive layer, the first pole piece 221, the first isolation film 222, the second pole piece 223 and the second isolation film 224 are wound to form the electrode assembly 22, and the electrode assembly 22 is heated to heat the second cured adhesive layer into an adhesive. Then, the electrode assembly 22 is hot-pressed to make the adhesive on both sides of the edge area of ​​the first body 2211 near the second pole ear 2232 bond to the first isolation film 222 and the second isolation film 224 respectively, so that the edge area of ​​the first body 2211 near the second pole ear 2232 is bonded to the first isolation film 222 by the adhesive, and the edge area of ​​the first body 2211 near the second pole ear 2232 is bonded to the second isolation film 224 by the adhesive.

[0210] Step S410 and step S420 can be completed by the same execution step, that is, after the first pole piece 221, the first isolation membrane 222, the second pole piece 223 and the second isolation membrane 224 are wound to form the electrode assembly 22, the connection area between the second body 2231 and the first isolation membrane 222 and the connection area between the second body 2231 and the first isolation membrane 222 in the electrode assembly 22 correspond to the position of the first pole ear 2212, and the connection area between the first body 2211 and the first isolation membrane 222 and the connection area between the first body 2211 and the first isolation membrane 222 correspond to the position of the second pole ear 2232.

[0211] Step S3111 and step S6111 can be completed by the same execution step, that is, after heating the electrode assembly 22, the first cured adhesive layer can be heated into an adhesive and the second cured adhesive layer can be heated into an adhesive simultaneously. Step S3121 and step S6121 can be completed by the same execution step, that is, hot pressing the electrode assembly 22, and the adhesive on both sides of the edge area of ​​the second body 2231 close to the first pole ear 2212 can be bonded to the first isolation film 222 and the second isolation film 224 respectively, and the adhesive on both sides of the edge area of ​​the first body 2211 close to the second pole ear 2232 can be bonded to the first isolation film 222 and the second isolation film 224 respectively.

[0212] Since the length of the first pole piece 221 is relatively large, after the first pole piece 221, the first isolation film 222, the second pole piece 223 and the second isolation film 224 are wound to form the electrode assembly 22, the electrode assembly 22 is heated to heat the second cured adhesive layer into an adhesive, so that when the electrode assembly 22 is heated, the heat can be concentrated to heat the electrode assembly 22, which can reduce energy consumption. After the second cured adhesive layer is heated to form an adhesive, the electrode assembly 22 is hot-pressed to make the adhesive on both sides of the edge area of ​​the first body 2211 close to the second pole ear 2232 bonded to the first isolation film 222 and the second isolation film 224 respectively, which not only realizes that the first isolation film 222 and the second isolation film 224 are bonded to the first body 2211, but also facilitates the further molding of the electrode assembly 22 and optimizes the preparation process of the electrode assembly 22. In the case where the second body 2231 is provided with a first cured adhesive layer, heating the electrode assembly 22 can simultaneously heat the first cured adhesive layer and the second cured adhesive layer to form an adhesive, thereby improving production efficiency.

[0213] like Fig.23 As shown, in some embodiments, the method for preparing the electrode assembly 22 further includes: Step S900 : connecting the edge regions of the first isolation film 222 close to the first electrode tab 2212 and the edge regions of the second isolation film 224 close to the first electrode tab 2212 on both sides of the second body 2231 .

[0214] The edge region of the first isolation film 222 near the first pole ear 2212 may be a region where the first isolation film 222 exceeds the first body 2211 and the second body 2231 on the side near the first pole ear 2212, which is defined as the first region 2213a. The edge region of the second isolation film 224 near the first pole ear 2212 may be a region where the first isolation film 222 exceeds the first body 2211 and the second body 2231 on the side near the first pole ear 2212, which is defined as the second region 2213b. The first region 2213a and the second region 2213b are connected, so that the risk of the first pole ear 2212 being inserted between the first isolation film 222 and the second body 2231 and the risk of the first pole ear 2212 being inserted between the second isolation film 224 and the second body 2231 are further reduced, and the risk of short circuit caused by contact between the first pole ear 2212 and the second body 2231 is further reduced, thereby reducing the risk of thermal runaway of the battery cell 20 having the electrode assembly 22, improving the reliability of the battery cell 20 and extending the service life of the battery cell 20 having the electrode assembly 22.

[0215] The edge regions of the first isolation film 222 close to the first pole tab 2212 and the edge regions of the second isolation film 224 close to the first pole tab 2212 on both sides of the second body 2231 may be connected by bonding.

[0216] like Fig.23 As shown, in some embodiments, the method for preparing the electrode assembly 22 further includes: Step S1000 : connecting the edge regions of the first isolation film 222 close to the second electrode tab 2232 and the edge regions of the second isolation film 224 close to the second electrode tab 2232 on both sides of the first body 2211 .

[0217] In an embodiment where the first pole ear 2212 and the second pole ear 2232 are located at the same end of the electrode assembly 22, the edge area of ​​the first isolation membrane 222 near the second pole ear 2232 can be the same as the edge area of ​​the first isolation membrane 222 near the first pole ear 2212, that is, the edge area of ​​the first isolation membrane 222 near the second pole ear 2232 is the first area 2213a of the first isolation membrane 222 that extends beyond the first body 2211 and the second body 2231 on the side near the first pole ear 2212; the edge area of ​​the second isolation membrane 224 near the second pole ear 2232 can be the same as the edge area of ​​the second isolation membrane 224 near the first pole ear 2212, that is, the edge area of ​​the second isolation membrane 224 near the second pole ear 2232 is the second area 2213b of the second isolation membrane 224 that extends beyond the first body 2211 and the second body 2231 on the side near the first pole ear 2212. The first region 2213a and the second region 2213b are connected, so the risk of the second pole ear 2232 being inserted between the first isolation membrane 222 and the first main body 2211 and the risk of the second pole ear 2232 being inserted between the second isolation membrane 224 and the first main body 2211 are further reduced, and the risk of short circuit caused by contact between the second pole ear 2232 and the first main body 2211 is further reduced, thereby reducing the risk of thermal runaway of the battery cell 20 having the electrode assembly 22, improving the reliability of the battery cell 20 and extending the service life of the battery cell 20 having the electrode assembly 22.

[0218] In the embodiment where the first pole tab 2212 and the second pole tab 2232 are located at opposite ends of the electrode assembly 22, the edge region of the first isolation film 222 near the second pole tab 2232 may be a region where the first isolation film 222 exceeds the first body 2211 and the second body 2231 on the side near the second pole tab 2232, which is defined as the third region 2233a. The edge region of the second isolation film 224 near the second pole tab 2232 may be a region where the second isolation film 224 exceeds the first body 2211 and the second body 2231 on the side near the second pole tab 2232, which is defined as the fourth region 2233b. When the third region 2233a and the fourth region 2233b are connected, the risk of the second pole ear 2232 being inserted between the first isolation membrane 222 and the first main body 2211 and the risk of the second pole ear 2232 being inserted between the second isolation membrane 224 and the first main body 2211 are further reduced, and the risk of short circuit caused by contact between the second pole ear 2232 and the first main body 2211 is further reduced, thereby reducing the risk of thermal runaway of the battery cell 20 having the electrode assembly 22, improving the reliability of the battery cell 20 and extending the service life of the battery cell 20 having the electrode assembly 22.

[0219] like Figure 4 As shown, an embodiment of the present application provides an electrode assembly 22, which includes a first electrode piece 221, a first isolation membrane 222, a second electrode piece 223 and a second isolation membrane 224, wherein the first electrode piece 221, the first isolation membrane 222, the second electrode piece 223 and the second isolation membrane 224 are stacked in sequence and wound to form a winding structure; the first electrode piece 221 includes a first main body 2211 and a first pole ear 2212, wherein the first pole ear 2212 is connected to one end of the first main body 2211, and the second electrode piece 223 includes a second main body 2231 and a second pole ear 2232, wherein the second pole ear 2232 is connected to one end of the second main body 2231; wherein the first isolation membrane 222 and the second isolation membrane 224 are both connected to the edge area of ​​the second main body 2231 close to the first pole ear 2212, and the connection area between the second main body 2231 and the first isolation membrane 222 and the connection area between the second main body 2231 and the second isolation membrane 224 are arranged corresponding to the first pole ear 2212.

[0220] By connecting the first isolation film 222 and the second isolation film 224 to the edge area of ​​the second body 2231 close to the first pole ear 2212, and the connection area between the second body 2231 and the first isolation film 222 and the connection area between the second body 2231 and the second isolation film 224 are arranged corresponding to the first pole ear 2212, there is no gap or the gap is insufficient for the first pole ear 2212 to be inserted between the second body 2231 and the first isolation film 222 and between the second body 2231 and the second isolation film 224 at the corresponding position of the first pole ear 2212, thereby reducing the risk of redundant insertion of the first pole ear 2212 between the second body 2231 and the first isolation film 222 and between the second body 2231 and the second isolation film 224, thereby reducing the risk of short circuit caused by contact between the first pole ear 2212 and the second body 2231, reducing the risk of thermal runaway of the battery cell 20 equipped with the electrode assembly 22, and improving the reliability of the battery cell 20.

[0221] like Figure 4 As shown, in some embodiments, the electrode assembly 22 includes a first adhesive layer 225 and a second adhesive layer 226, the first isolation film 222 and the edge area of ​​the second body 2231 near the first pole ear 2212 are bonded by the first adhesive layer 225, and the second isolation film 224 and the edge area of ​​the second body 2231 near the first pole ear 2212 are bonded by the second adhesive layer 226.

[0222] The first adhesive layer 225 and the second adhesive layer 226 may be formed by heating the aforementioned first cured adhesive layer to form an adhesive.

[0223] The first isolation film 222 and the second main body 2231 are bonded to the edge area near the first pole ear 2212 by the first adhesive layer 225, and the second isolation film 224 and the second main body 2231 are bonded to the edge area near the first pole ear 2212 by the second adhesive layer 226, so that connecting the first isolation film 222 and the second main body 2231, and connecting the second isolation film 224 and the second main body 2231 are more convenient, and the connection stability between the first isolation film 222 and the second main body 2231, and between the second isolation film 224 and the second main body 2231 is better.

[0224] In some embodiments, the electrode assembly 22 includes a plurality of first adhesive layers 225 and a plurality of second adhesive layers 226 , wherein the plurality of first adhesive layers 225 are spaced apart along the length direction of the second electrode piece 223 , and the plurality of second adhesive layers 226 are spaced apart along the length direction of the second electrode piece 223 .

[0225] When the first pole piece 221 and the second pole piece 223 are in a wound state, the length direction of the first pole piece 221 and the length direction of the second pole piece 223 are both consistent with the winding direction of the electrode assembly 22 .

[0226] The plurality of first adhesive layers 225 are arranged at intervals along the length direction of the second pole piece 223, and can be formed by applying adhesive at intervals on the side of the second body 2231 of the second pole piece 223 facing the first isolation film 222. The plurality of second adhesive layers 226 are arranged at intervals along the length direction of the second pole piece 223, and can be formed by applying adhesive at intervals on the side of the second body 2231 of the second pole piece 223 facing the second isolation film 224.

[0227] Multiple first adhesive layers 225 are arranged at intervals along the length direction of the second pole piece 223, and multiple second adhesive layers 226 are arranged at intervals along the length direction of the second pole piece 223, so that a smaller area of ​​the second body 2231 is covered by the slurry, which is beneficial to the wetting of the second pole piece 223, thereby facilitating the improvement of the cycle performance and life of the battery cell 20 having the electrode assembly 22.

[0228] In other embodiments, the first glue layer 225 may be a continuous structure extending along the length direction of the second pole piece 223, and the first glue layer 225 may be formed by continuously applying glue along the length direction of the second pole piece 223 on the side of the second body 2231 facing the first isolation film 222. The length of the first glue layer 225 may be the same as the length of the second pole piece 223. The length of the first glue layer 225 may also be different from the length of the second pole piece 223. The second glue layer 226 may be a continuous structure extending along the length direction of the second pole piece 223, and the second glue layer 226 may be formed by continuously applying glue along the length direction of the second pole piece 223 on the side of the second body 2231 facing the second isolation film 224. The length of the second glue layer 226 may be the same as the length of the second pole piece 223. The length of the second glue layer 226 may also be different from the length of the second pole piece 223.

[0229] The first adhesive layer 225 and the second adhesive layer 226 are continuous structures extending along the length direction of the second pole piece 223, and can be formed by continuously coating slurry along the length direction of the second body 2231 on both sides of the edge area of ​​the second body 2231 close to the first pole ear 2212. The formation of the first adhesive layer 225 and the second adhesive layer 226 is more convenient, and is beneficial to increase the bonding area between the second body 2231 and the first isolation film 222, and between the second body 2231 and the second isolation film 224, which not only provides bonding stability, but also reduces the risk of inserting the first pole ear 2212 between the second body 2231 and the first isolation film 222, and between the second body 2231 and the second isolation film 224 after being misplaced.

[0230] In some embodiments, along the length direction of the second electrode piece 223 , the first adhesive layer 225 is located between two adjacent second electrode tabs 2232 , and the second adhesive layer 226 is located between two adjacent second electrode tabs 2232 .

[0231] The first adhesive layer 225 and the second adhesive layer 226 are both disposed to avoid the second electrode tab 2232 .

[0232] The first adhesive layer 225 and the second adhesive layer 226 are both located between two adjacent second pole tabs 2232 , and the second adhesive layer 226 is located between two adjacent second pole tabs 2232 , which reduces the risk of interference between the first adhesive layer 225 and the second adhesive layer 226 and the second pole tabs 2232 , and is beneficial for the second pole tabs 2232 to have better conductive properties.

[0233] In some embodiments, the first isolation film 222 and the second isolation film 224 are both connected to the edge area of ​​the first body 2211 near the second pole ear 2232, and the connection area between the first body 2211 and the first isolation film 222 and the connection area between the first body 2211 and the second isolation film 224 are arranged corresponding to the second pole ear 2232.

[0234] By connecting the first isolation film 222 and the second isolation film 224 to the edge area of ​​the first body 2211 close to the second pole ear 2232, and the connection area between the first body 2211 and the first isolation film 222 and the connection area between the first body 2211 and the second isolation film 224 are arranged corresponding to the second pole ear 2232, at the corresponding position of the second pole ear 2232, there is no gap between the first body 2211 and the first isolation film 222, and between the first body 2211 and the second isolation film 224, or the gap is not enough for the second pole ear 2232 to be inserted, thereby reducing the risk of redundant insertion of the second pole ear 2232 between the first body 2211 and the first isolation film 222 and between the first body 2211 and the second isolation film 224, thereby reducing the risk of short circuit caused by contact between the second pole ear 2232 and the first body 2211, reducing the risk of thermal runaway of the battery cell 20 equipped with the electrode assembly 22, and improving the reliability of the battery cell 20.

[0235] In some embodiments, in some embodiments, the electrode assembly 22 includes a third glue layer 227 and a fourth glue layer 228, the first isolation film 222 is bonded to the edge area of ​​the first body 2211 near the second pole ear 2232 through the third glue layer 227, and the second isolation film 224 is bonded to the edge area of ​​the first body 2211 near the second pole ear 2232 through the second glue layer 226.

[0236] The third adhesive layer 227 and the fourth adhesive layer 228 may be formed by heating the aforementioned second cured adhesive layer.

[0237] The first isolation film 222 is bonded to the edge area of ​​the first main body 2211 near the second pole ear 2232 by the third adhesive layer 227, and the second isolation film 224 is bonded to the edge area of ​​the first main body 2211 near the second pole ear 2232 by the fourth adhesive layer 228, so that it is more convenient to connect the first isolation film 222 and the first main body 2211, and to connect the second isolation film 224 and the first main body 2211, and the connection stability between the first isolation film 222 and the first main body 2211, and between the second isolation film 224 and the first main body 2211 is better.

[0238] The embodiment of the present application further provides a battery cell 20 , and the battery cell 20 includes the electrode assembly 22 provided in any of the above embodiments.

[0239] The electrode assembly 22 provided in the above embodiment has a lower risk of thermal runaway, and therefore, the battery cell 20 having the electrode assembly 22 has better reliability.

[0240] The embodiment of the present application further provides a battery device 100 , and the battery device 100 includes the battery cell 20 provided in the above embodiment.

[0241] The battery cell 20 provided in the above embodiment has good reliability, and the battery device 100 including the battery cell 20 also has good reliability.

[0242] An embodiment of the present application provides an electrical device, which includes the battery cell 20 provided in the above embodiment or the battery device 100 provided in the above embodiment.

[0243] The battery cells 20 and the battery device 100 provided in the above embodiments have good reliability, and the power consumption reliability of the power consumption device powered by the battery cells 20 or the battery device 100 is also good.

[0244] The embodiment of the present application provides a method for preparing an electrode assembly 22, and the method for preparing the electrode assembly 22 includes: step S100: providing a first electrode piece 221, a first isolation film 222, a second electrode piece 223, and a second isolation film 224; the first electrode piece 221 includes a first body 2211 and a first pole ear 2212, the first pole ear 2212 is connected to one end of the first body 2211, and the second electrode piece 223 includes a second body 2231 and a second pole ear 2232, the second pole ear 2232 is connected to one end of the second body 2231; after step S100, performing step S5111: applying slurry at intervals along the length direction of the second body 2231 on one side of the edge area of ​​the second body 2231 close to the first pole ear 2212. After step S5111 is completed, the slurry applied to the second body 2231 in step S5111 is dried, and a first cured adhesive layer is formed on one side of the edge area of ​​the second body 2231 close to the first pole ear 2212. Then, step S5121 is performed: the slurry is applied at intervals along the length direction of the second body 2231 on the other side of the edge region of the second body 2231 close to the first pole ear 2212. After step S5121 is completed, the slurry applied to the second body 2231 in step S5121 is dried to form a first cured adhesive layer on the other side of the edge region of the second body 2231 close to the first pole ear 2212. After step S100, step S8111 is performed: the slurry is applied at intervals along the length direction of the first body 2211 on the side of the edge region of the first body 2211 close to the second pole ear 2232; after step S8111 is completed, the slurry applied to the first body 2211 in step S8111 is dried to form a second cured adhesive layer on the side of the edge region of the first body 2211 close to the second pole ear 2232. Then, step S8121 is performed: the slurry is applied at intervals along the length direction of the first body 2211 on the other side of the edge region of the first body 2211 close to the second pole ear 2232. After step S8121 is completed, the slurry applied to the first body 2211 in step S8121 is dried to form a second cured adhesive layer on the other side of the edge region of the first body 2211 close to the second pole ear 2232. After the first cured adhesive layer is formed on both sides of the edge region of the second body 2231 close to the first pole ear 2212 and the second cured adhesive layer is formed on both sides of the edge region of the first body 2211 close to the second pole ear 2232, step S200 is performed: the first pole piece 221, the first isolation film 222, the second pole piece 223 and the second isolation film 224 are stacked in sequence; after step S200 is completed, steps S410 and S420 are performed: the first pole piece 221, the first isolation film 222, the second pole piece 223 and the second isolation film 224 are wound to form the electrode assembly 22.After step S410 and step S420 are executed, step S3111 is executed: heating the electrode assembly 22 to heat the first cured adhesive layer into adhesive and step S6111 is executed: heating the electrode assembly 22 to heat the second cured adhesive layer into adhesive. After step S3111 and step S6111 are executed, steps S3121 and step S6121 are executed: hot pressing the electrode assembly 22 to make the adhesive on both sides of the edge area of ​​the second body 2231 close to the first pole ear 2212 bonded to the first isolation film 222 and the second isolation film 224 respectively, so that the connection area between the second body 2231 and the first isolation film 222 and the connection area between the second body 2231 and the second isolation film 224 are arranged corresponding to the first pole ear 2212.

[0245] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0246] The above embodiments are only used to illustrate the technical solution of the present application and are not used to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing an electrode assembly, characterized in that: include: Step S100: providing a first pole piece, a first isolation film, a second pole piece and a second isolation film; The first pole piece includes a first body and a first pole ear, the first pole ear is connected to one end of the first body, and the second pole piece includes a second body and a second pole ear, the second pole ear is connected to one end of the second body; Step S200: stacking the first pole piece, the first isolation film, the second pole piece and the second isolation film in sequence; Step S300: connecting the first isolation film and the second isolation film to the edge area of ​​the second body close to the first electrode tab; Step S400: Winding the first pole piece, the first isolation membrane, the second pole piece and the second isolation membrane to form an electrode assembly, so that the connection area between the second body and the first isolation membrane and the connection area between the second body and the second isolation membrane are arranged corresponding to the first pole lug.

2. The method for preparing an electrode assembly according to claim 1, wherein: The step S300 includes: Step S310: bonding the first isolation film and the second isolation film to the edge region of the second body close to the first electrode tab.

3. The method for preparing an electrode assembly according to claim 2, wherein: Before step S200, the method for preparing the electrode assembly further includes: Step S500: disposing a first cured adhesive layer on both sides of the edge area of ​​the second body close to the first electrode tab; Step S310 includes: Step S311: heating the first curing adhesive layer into an adhesive; Step S312: bonding the adhesive on both sides of the edge region of the second body close to the first electrode tab to the first isolation film and the second isolation film respectively.

4. The method for preparing an electrode assembly according to claim 3, wherein: The step S500 includes: Step S510: coating slurry on both sides of the edge area of ​​the second body close to the first electrode tab; Step S520: drying the slurry so that the slurry forms the first cured adhesive layer on both sides of the edge area of ​​the second body close to the first electrode tab.

5. The method for preparing an electrode assembly according to claim 4, characterized in that: The step S510 includes: Step S511: coating slurry on one side of the edge area of ​​the second body close to the first electrode tab; Step S512: coating slurry on the other side of the edge region of the second body close to the first electrode tab.

6. The method for preparing an electrode assembly according to claim 5, characterized in that: The step S511 comprises: Step S5111: coating slurry at intervals along the length direction of the second body on one side of the edge region of the second body close to the first electrode tab; The step S512 includes: Step S5121: applying slurry at intervals along the length direction of the second body on the other side of the edge region of the second body close to the first electrode tab.

7. The method for preparing an electrode assembly according to claim 5, wherein: The step S511 comprises: Step S5111: continuously coating the slurry on one side of the edge region of the second body close to the first electrode tab along the length direction of the second body; The step S512 includes: Step S5121: Continuously apply slurry along the length direction of the second body on the other side of the edge region of the second body close to the first electrode tab.

8. The method for preparing an electrode assembly according to claim 4, characterized in that: After step S520, step S400 includes: Step S410: Winding the first pole piece, the first isolation film, the second pole piece and the second isolation film to form an electrode assembly; The step S311 includes: Step S3111: heating the electrode assembly to heat the first cured adhesive layer into an adhesive; The step S312 includes: Step S3121: hot pressing the electrode assembly so that the adhesive on both sides of the edge region of the second body close to the first electrode tab is bonded to the first isolation film and the second isolation film respectively.

9. The method for preparing an electrode assembly according to claim 1, wherein: The method for preparing the electrode assembly further includes: Step S600: connecting the first isolation film and the second isolation film to the edge area of ​​the first body close to the second electrode tab; The step S400 includes: Step S420: Winding the first pole piece, the first isolation membrane, the second pole piece and the second isolation membrane to form an electrode assembly, so that the connection area between the first body and the first isolation membrane and the connection area between the first body and the second isolation membrane are arranged corresponding to the second pole lug.

10. The method for preparing an electrode assembly according to claim 9, characterized in that: The step S600 includes: Step S610: bonding the first isolation film and the second isolation film to the edge area of ​​the first body close to the second electrode tab.

11. The method for preparing an electrode assembly according to claim 10, characterized in that: Before step S200, the method for preparing the electrode assembly further includes: Step S800: disposing a second cured adhesive layer on both sides of the edge area of ​​the first body close to the second electrode tab; Step S610 includes: Step S611: heating the second cured adhesive layer into an adhesive; Step S612: bonding the adhesive on both sides of the edge region of the first body close to the second electrode tab to the first isolation film and the second isolation film respectively.

12. The method for preparing an electrode assembly according to claim 11, characterized in that: The step S800 includes: Step S810: coating slurry on both sides of the edge area of ​​the first body close to the second electrode tab; Step S820: drying the slurry so that the slurry forms the second cured adhesive layer on both sides of the edge area of ​​the first body close to the second electrode tab.

13. The method for preparing an electrode assembly according to claim 12, wherein: After step S820 and after step S420, step S611 includes: Step S6111: heating the electrode assembly to heat the second cured adhesive layer into an adhesive; The step S612 includes: Step S6121: hot pressing the electrode assembly so that the adhesive on both sides of the edge region of the first body close to the second electrode tab is bonded to the first isolation film and the second isolation film respectively.

14. The method for preparing an electrode assembly according to claim 1, wherein: The method for preparing the electrode assembly further includes: Step S900: connecting edge regions of the first isolation film close to the first electrode tab and edge regions of the second isolation film close to the first electrode tab on both sides of the second body.

15. The method for preparing an electrode assembly according to claim 1, wherein: The method for preparing the electrode assembly further includes: Step S1000: connecting edge regions of the first isolation film close to the second electrode tab and edge regions of the second isolation film close to the second electrode tab on both sides of the first body.

16. An electrode assembly, characterized in that: include: A first pole piece, a first isolation film, a second pole piece and a second isolation film, wherein the first pole piece, the first isolation film, the second pole piece and the second isolation film are sequentially stacked and wound to form a winding structure; the first pole piece includes a first body and a first pole ear, the first pole ear is connected to one end of the first body, and the second pole piece includes a second body and a second pole ear, the second pole ear is connected to one end of the second body; The first isolation membrane and the second isolation membrane are both connected to the edge area of ​​the second body close to the first pole lug, and the connection area between the second body and the first isolation membrane and the connection area between the second body and the second isolation membrane are arranged corresponding to the first pole lug.

17. The electrode assembly according to claim 16, characterized in that The electrode assembly includes a first adhesive layer and a second adhesive layer, the first isolation film and the second body are bonded to an edge area near the first electrode tab through the first adhesive layer, and the second isolation film and the second body are bonded to an edge area near the first electrode tab through the second adhesive layer.

18. The electrode assembly according to claim 17, characterized in that The electrode assembly includes a plurality of the first glue layers and a plurality of the second glue layers, wherein the plurality of the first glue layers are arranged at intervals along the length direction of the second pole piece, and the plurality of the second glue layers are arranged at intervals along the length direction of the second pole piece.

19. The electrode assembly according to claim 18, characterized in that Along the length direction of the second pole piece, the first adhesive layer is located between two adjacent second pole tabs, and the second adhesive layer is located between two adjacent second pole tabs.

20. The electrode assembly according to claim 16, wherein: The first isolation film and the second isolation film are both connected to the edge area of ​​the first body close to the second pole lug, and the connection area between the first body and the first isolation film and the connection area between the first body and the second isolation film are arranged corresponding to the second pole lug.

21. A battery cell, characterized in that: An electrode assembly comprising any one of claims 16-20.

22. A battery device, characterized in that: Comprising the battery cell as claimed in claim 21.

23. An electrical device, characterized in that: Comprising the battery cell according to claim 21 or the battery device according to claim 22.

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