Electrode assembly, molding method thereof, and manufacturing system, secondary battery, battery module, and device

Abstract

To provide an electrode assembly, a forming method for the same, a manufacturing system, a secondary battery, a battery module, and a device.SOLUTION: An electrode assembly includes a first electrode sheet, and a second electrode sheet with a polarity opposite that of the first electrode sheet. The first electrode sheet includes a plurality of bent parts 511 and a plurality of first multilayer parts 512 including a stack of layers. Each bent part is used for connecting two of the first multilayer parts that are adjacent to each other. Here, the bent part includes a guide part that guides so that the bent part is bent during manufacture. The second electrode sheet includes a plurality of second multilayer parts. Each of the second multilayer parts is provided between the two adjacent first multilayer parts. It is possible to ensure that the electrode assembly according to this example exists at a predetermined position after the first electrode sheet and the second electrode sheet are stacked, and thus, it is possible to ensure that the secondary battery has excellent electrochemical performance.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] This application claims priority from Chinese Patent Application No. 201911224967.7, entitled "Stacked Battery Cell Manufacturing System and Stacked Battery Cell Forming Method," filed on December 4, 2019, the entire contents of which are incorporated herein by reference.

[0002] The present application relates to the field of battery technology, and in particular to an electrode assembly and a manufacturing method and system thereof, a secondary battery, a battery module, and an apparatus. [Background technology]

[0003] With the development of society and science and technology, secondary batteries are widely applied to provide power to high-power devices, such as electric vehicles, etc. Secondary batteries achieve greater capacity or power by connecting multiple battery cells in series or parallel to form a battery module.

[0004] A secondary battery includes a cathode sheet and an anode sheet, and the cathode sheet and the anode sheet are stacked to form an electrode assembly. However, after the cathode sheet and the anode sheet are stacked together, at least one of the cathode sheet and the anode sheet may shift from a predetermined position, thereby affecting the electrochemical performance of the secondary battery. Summary of the Invention

[0005] The embodiments of the present application provide an electrode assembly, a molding method thereof, a manufacturing system, a secondary battery, a battery module, and an apparatus that can ensure that the first electrode sheet and the second electrode sheet are in a predetermined position after being laminated, thereby ensuring that the secondary battery has good electrochemical performance.

[0006] In one aspect, an embodiment of the present application provides an electrode assembly for use in a secondary battery, the electrode assembly comprising: a first electrode sheet; and a second electrode sheet having an opposite polarity to the first electrode sheet; the first electrode sheet includes a plurality of folding portions and a plurality of stacked first laminate portions, each folding portion being used to connect two adjacent first laminate portions, wherein the folding portion has a guide portion that guides the folding portion so that it is folded during manufacturing; and the second electrode sheet includes a plurality of second laminate portions, each second laminate portion being disposed between two adjacent first laminate portions.

[0007] In another aspect, an embodiment of the present application provides a secondary battery including the electrode assembly according to the embodiment.

[0008] In another aspect, an embodiment of the present application provides a battery module including the secondary battery according to the embodiment.

[0009] In another aspect, embodiments of the present application provide a device that supplies electrical energy and includes a secondary battery according to any of the above embodiments.

[0010] In another aspect, embodiments of the present disclosure provide a method for forming an electrode assembly, the method comprising: providing a first electrode sheet including a plurality of folding portions and a plurality of first laminated portions, each folding portion being used to connect two adjacent first laminated portions, wherein the folding portion has a guide portion; providing a second electrode sheet having an opposite polarity to the first electrode sheet, the second electrode sheet including a plurality of second laminated sections, each second laminated section being disposed between two adjacent first laminated sections; and a step of stacking two adjacent first stacked portions connected to the folding portion by folding the folding portion along the guide portion.

[0011] In another aspect, embodiments of the present disclosure provide a system for manufacturing an electrode assembly, the system comprising: a first conveying mechanism for providing a first electrode sheet including a plurality of folded portions and a plurality of stacked first laminated portions, each folded portion being used to connect two adjacent first laminated portions; a trace forming mechanism used to provide a guide portion at the folding portion for guiding the folding portion during manufacturing; a second conveying mechanism for providing a second electrode sheet having an opposite polarity to the first electrode sheet, the second electrode sheet including a plurality of second stacked portions, each second stacked portion being disposed between two adjacent first stacked portions; and a stacking mechanism used to fold the folding portion along the guide portion and stack two adjacent first stacked portions connected to the folding portion.

[0012] The beneficial effects of the present invention are as follows: By providing a guide section at the folding section, the folding section is folded along the guide section during manufacturing, ensuring a more accurate folding position when the folding section is folded relative to the first stacked section, thereby ensuring that the first and second electrode sheets are in a predetermined position after being stacked, and that the secondary battery has good electrochemical performance. [Brief explanation of the drawings]

[0013] The features, advantages, and technical effects of exemplary embodiments of the present application are described below with reference to the drawings. [Figure 1] 1 is a structural schematic diagram of a vehicle disclosed in an embodiment of the present application. [Figure 2] 1 is a schematic exploded view of a battery pack disclosed in an embodiment of the present application; [Figure 3] 1 is a schematic diagram of a local structure of a battery module disclosed in an embodiment of the present application; [Figure 4] 1 is a schematic exploded view of a secondary battery disclosed in an embodiment of the present application; [Figure 5] 3 is a schematic diagram of a local planar structure of a first electrode sheet according to an embodiment of the present application before folding. FIG. [Figure 6]FIG. 6 is a schematic diagram of a side structure of a first electrode sheet according to the embodiment shown in FIG. 5. [Figure 7] 6 is a structural schematic diagram of the first electrode sheet according to the embodiment shown in FIG. 5 in a folded state. FIG. [Figure 8] 6 is a schematic diagram of a connection structure of a first electrode sheet, a second electrode sheet, and a separator according to the embodiment shown in FIG. 5. FIG. [Figure 9] 1 is a schematic side view of an electrode assembly according to an embodiment of the present invention; [Figure 10] 10 is a first structural schematic diagram in a plan view of the electrode assembly according to the embodiment shown in FIG. 9. FIG. [Figure 11] 10 is a second structural schematic diagram in a plan view of the electrode assembly according to the embodiment shown in FIG. 9. FIG. [Figure 12] FIG. 10 is a schematic side view of an electrode assembly according to another embodiment of the present application; [Figure 13] FIG. 10 is a structural schematic diagram of a first electrode sheet in a folded state according to another embodiment of the present application. [Figure 14] 14 is a schematic side view of the electrode assembly including the first electrode sheet according to the embodiment shown in FIG. 13. FIG. [Figure 15] FIG. 10 is a structural schematic diagram of a first electrode sheet in a folded state according to another embodiment of the present application. [Figure 16] FIG. 10 is a structural schematic diagram of a first electrode sheet in a folded state according to another embodiment of the present application. [Figure 17] 17 is a schematic cross-sectional structural diagram of a side view of an electrode assembly including a first electrode sheet according to the embodiment shown in FIG. 16. FIG. [Figure 18] FIG. 10 is a structural schematic diagram of a first electrode sheet in a folded state according to another embodiment of the present application. [Figure 19] FIG. 10 is a schematic side view of an electrode assembly according to another embodiment of the present application; [Figure 20] FIG. 10 is a schematic side view of an electrode assembly according to another embodiment of the present application; [Figure 21] 1 is a structural schematic diagram of a stacked battery cell manufacturing system according to an embodiment of the present application. [Figure 22] 1 is a structural schematic diagram of a first transport mechanism according to an embodiment of the present application. [Figure 23] 1 is a structural schematic diagram of an anode sheet and a trace forming mechanism according to an embodiment of the present application; FIG. [Figure 24] 1 is a schematic diagram of an anode sheet having a mark according to an embodiment of the present application. [Figure 25] FIG. 2 is a structural schematic diagram of a second transport mechanism according to an embodiment of the present application. [Figure 26] 1 is a structural schematic diagram of a composite mechanism according to an embodiment of the present application. [Figure 27] 1 is a structural schematic diagram of a heating and conveying assembly according to an embodiment of the present application; [Figure 28] FIG. 28 is a plan view of the structure shown in FIG. 27. [Figure 29] 1 is a structural schematic diagram of a stacking mechanism according to an embodiment of the present application. [Figure 30] FIG. 30 is a bottom view of the structure shown in FIG. 29. [Figure 31] 1 is a schematic diagram illustrating the cooperation of a stacking mechanism with a main transport mechanism and an assembly to be stacked according to an embodiment of the present application.In the drawings, the figures are not drawn to scale. [Explanation of symbols]

[0014] 1 vehicle 10 Battery pack 20 Battery Module 30 Secondary battery 40 cases 50 electrode assembly 50a Main body 50b tab 51 First electrode sheet 51a Current collector 51b Electrode active material layer 511 Bending part 511a connection 511b Intermediate transition section 5110 Weak region 5111 Guide part 5111a Groove 5111b Through hole 5112 Second outer edge 512, first stacked portion 5121 First outer edge 52 Second electrode sheet 521 second laminated part 5211 Third Outer Edge 53 Separator 60 Top cover assembly 61 Top cover plate 62 Electrode terminal 70 Adapter seat W Extension direction H thickness direction X first direction Y Second direction Z-fold direction 100 First transport mechanism 101 First unwinding device 102 First belt connecting device 103 First tension balance device 104 First deviation calibration device 105 First dust removal device 200 Separator conveying mechanism 300 Trace formation mechanism 301 First trace-forming member 302 Second trace-forming member 400 Second transport mechanism 401 Second unwinding device 402 Second belt connecting device 403 Second tension balance device 404 Second deviation calibration device 405 Cutting device 406 Second Dust Removal Device 4061 Belt Brush 4062 Dust suction device 500 complex mechanism 501 Heating conveying assembly 5011 Heating element 5012 Conveying member 5012a Transmission wheel 5012b Transmission Belt 502 Roller pressing member 5021 Pressure roller 503 Dust removal member 600 Lamination Mechanism 601 Power source 602 Oscillating mechanism 6021 Gap 6022 Mounting base 6023 Clamping roller 6024 Limit Reinforcement Roller 700 Main transport mechanism DETAILED DESCRIPTION OF THE INVENTION

[0015] The embodiments of the present application will be described in more detail below with reference to the drawings and examples. The detailed description and drawings of the following examples are used to exemplify the principles of the present application, but are not intended to limit the scope of the present application, i.e., the present application is not limited to the described examples.

[0016] In the description of this application, unless otherwise specified, "plurality" means two or more. Terms such as "upper," "lower," "left," "right," "inner," and "outer" indicate orientations or positional relationships solely for the purpose of facilitating and simplifying the description of this application and do not indicate or imply that the designated device or element must have a particular orientation, be constructed, or operate in a particular orientation, and should not be understood as limiting this application. Furthermore, terms such as "first," "second," and the like are used solely for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0017] All directional terms appearing in the following description refer to the directions shown in the drawings and do not limit the specific structure of the present application. As will be further explained in the description of the present application, unless otherwise clearly specified or limited, the terms "attached," "coupled," and "connected" should be understood in a broad sense, and may refer to, for example, a fixed connection, a detachable connection, or an integral connection. They may also be directly connected or indirectly connected via an intermediate medium. Those skilled in the art can understand the specific meanings of the above terms in the present application according to the specific circumstances.

[0018] For a better understanding of the present invention, an embodiment of the present invention will be described below with reference to FIGS.

[0019] An embodiment of the present application provides an apparatus that uses a secondary battery 30 as a power source. This apparatus may be, but is not limited to, a vehicle, a ship, or an aircraft. As shown in FIG. 1 , one embodiment of the present application provides a vehicle 1 including a vehicle body and a battery module. The battery module is installed in the vehicle body. Here, the vehicle 1 may be a pure electric vehicle, a hybrid vehicle, or an extended-range vehicle. The vehicle body is equipped with a drive motor electrically connected to the battery module. The battery module supplies electric energy to the drive motor. The drive motor is connected to wheels of the vehicle body via a transmission mechanism, thereby driving the vehicle. Preferably, the battery module may be installed horizontally at the bottom of the vehicle body.

[0020] As shown in FIG. 2 , the battery module may be a battery pack 10. The battery pack 10 may be installed in various ways. In some alternative embodiments, the battery pack 10 includes a housing and a battery module 20 installed in the housing. The number of battery modules 20 may be one or more. The one or more battery modules 20 are arranged in an array within the housing. The type of housing is not limited. The housing may be a frame-shaped housing, a dish-shaped housing, a box-shaped housing, or the like. Preferably, the housing includes a lower housing for accommodating the battery module 20 and an upper housing covered by the lower housing. The upper and lower housings form a housing for accommodating the battery module 20 after being closed. As can be understood, the battery module may be the battery module 20, i.e., the battery module 20 is directly installed in the vehicle body.

[0021] As shown in FIG. 3 , the battery module 20 includes a plurality of secondary batteries 30. The battery module 20 may be installed in various ways. In one embodiment, the battery module 20 includes a receiving portion and a plurality of secondary batteries 30 located within the receiving portion. The plurality of secondary batteries 30 are arranged side by side within the receiving portion. The receiving portion may be installed in various ways. For example, the receiving portion may include a housing and a cover plate installed to cover the housing. Alternatively, the receiving portion may include side plates and end plates connected in series. Alternatively, the receiving portion may include two end plates installed opposite each other and a band wrapped around the end plates and the secondary batteries 30.

[0022] The applicant, after focusing on the problem of poor electrochemical performance in conventional secondary batteries, discovered that at least one of the cathode sheet and the anode sheet in a molded electrode assembly is misaligned from its predetermined position, affecting the electrochemical performance of the secondary battery. The applicant further discovered that when at least one of the cathode sheet and the anode sheet in a molded electrode assembly is misaligned from its predetermined position, lithium deposition occurs in the electrode assembly, thereby affecting the electrochemical performance of the secondary battery. It is speculated that this may be due to the size of the portion of the anode sheet that extends beyond the outer edge of the cathode sheet being too small, or the anode sheet not extending beyond the outer edge of the cathode sheet.

[0023] By analyzing the assembly process of the electrode assembly, the applicant further studied the lithium deposition phenomenon and found, taking the example of installing the anode sheet continuously and the cathode sheet intermittently, that because the anode sheet is difficult to fold along a predetermined region during the folding process, after the cathode sheet and the anode sheet are stacked to form the electrode assembly, the dimension of the portion of the anode sheet that extends beyond the outer edge of the cathode sheet may be too small, making it easy for lithium deposition to occur in the electrode assembly, which will affect the electrochemical performance and safety of the secondary battery.

[0024] Based on the above problems discovered by the applicant, the applicant has improved the structure of the electrode assembly 50, and the embodiments of the present application will be further described below.

[0025] As shown in FIG. 4, the secondary battery 30 according to the embodiment of the present invention includes a case 40 , an electrode assembly 50 installed in the case 40 , and a top cover assembly 60 hermetically connected to the case 40 .

[0026] The case 40 according to this embodiment may have a rectangular structure or other shapes. The case 40 has an internal space for accommodating the electrode assembly 50 and the electrolyte, and an opening communicating with the internal space. The case 40 may be made of a material such as aluminum, an aluminum alloy, or plastic.

[0027] The top cover assembly 60 according to this embodiment includes a top cover plate 61 and an electrode terminal 62. The top cover plate 61 according to this embodiment has opposing outer and inner surfaces, and an electrode lead-out hole penetrating the outer and inner surfaces. The top cover plate 61 can cover the opening of the case 40 and is hermetically connected to the case 40. The inner surface of the top cover 61 faces the electrode assembly 50. The electrode terminal 62 is provided on the top cover plate 61 and is provided to correspond to the electrode lead-out hole. A portion of the electrode terminal 62 is exposed on the outer surface of the top cover plate 61 and is used for welding to a bus bar.

[0028] The electrode assembly 50 according to the present embodiment includes a main body 50a and tabs 50b extending from the main body 50a. In the present embodiment, one tab 50b extends from each of two opposing end surfaces of the main body 50a. In some other embodiments, two tabs 50b extend from one of the two opposing end surfaces of the main body 50a. The two tabs 50b have opposite polarities, one being a cathode tab and the other being an anode tab. The active material of the cathode sheet is applied to the coated area of ​​the cathode sheet, and the active material of the anode sheet is applied to the coated area of ​​the anode sheet. Multiple uncoated areas extending from the coated area of ​​the main body 50a are stacked as tabs 50b. The cathode tab extends from the coated area of ​​the cathode sheet, and the anode tab extends from the coated area of ​​the anode sheet. The adapter sheet 70 connects the tabs 50b of the electrode assembly 50 to the electrode terminal 62.

[0029] In one embodiment, FIG. 5 schematically illustrates the local structure of a first electrode sheet 51 in an unfolded state. As shown in FIG. 5, the first electrode sheet 51 includes a plurality of folded portions 511 and a plurality of first laminated portions 512, where the folded portions 511 are at least partially folded after being folded. The first electrode sheet 51 has a continuous extending structure as a whole. The folded portions 511 and the first laminated portions 512 are alternately arranged along the extending direction W of the first electrode sheet 51 itself. Each folded portion 511 is connected to two adjacent first laminated portions 512. Along the first direction X, each first laminated portion 512 has two opposing first outer edges 5121, and each folded portion 511 has two opposing second outer edges 5112. The first direction X is the same as the width direction of the first electrode sheet 51. The first direction X is perpendicular to the extending direction W. In this embodiment, the first outer edge 5121 and the second outer edge 5112, which are located on the same side along the first direction X, are aligned. The first electrode sheet 51 further includes tabs 50b extending in the first direction X from the first outer edge 5121 of the first laminated portion 512. The number and positions of the tabs 50b correspond one-to-one to the number and positions of the first laminated portion 512. In this embodiment, the first electrode sheet 51 includes guide portions 5111 provided on the folding portions 511. The number of guide portions 5111 may be the same as the number of folding portions 511. Of course, as can be understood, the guide portions 5111 may be provided on some of the folding portions 511, and the guide portions 5111 may not be provided on other folding portions 511. The guide portions 5111 are provided to guide the folding of the folding portions 511 during manufacturing. During the manufacturing process, when an external force is applied to the first electrode sheet 51 to perform the bending operation, the guide portion 5111 is installed at the bending portion 511, so that the bending portion 511 can easily achieve bending in the area where the guide portion 5111 is located, thereby improving the controllability and accuracy of the bending position, and further ensuring that the first electrode sheet 51 and the second electrode sheet 52 are respectively in the predetermined positions, and ensuring that the secondary battery 30 has good electrochemical performance.

[0030] FIG. 6 schematically illustrates a side view of the first electrode sheet 51 according to the embodiment shown in FIG. 5. The first electrode sheet 51 includes a current collector 51a and an electrode active material layer 51b applied to the current collector 51a. The current collector 51a has two opposing surfaces in the thickness direction H of the first electrode sheet 51. Two electrode active material layers 51b are provided on each of the two surfaces. In one example, when the first electrode sheet 51 is a cathode sheet, the current collector 51a is made of a metal material such as aluminum or an aluminum alloy. When the first electrode sheet 51 is an anode sheet, the current collector 51a is made of a metal material such as copper or a copper alloy. The guide portion 5111 may be a trace of an object. Alternatively, it may refer to a structure formed after removing a portion of the electrode active material layer 51b from the first electrode sheet 51 using a material removal tool, or after removing a portion of the electrode active material layer 51b and a portion of the current collector 51a from the first electrode sheet 51.

[0031] In this embodiment, a guide portion 5111 is provided at each folding portion 511. In this embodiment, the guide portion 5111 includes a groove 5111a. The groove 5111a extends from the surface of the first electrode sheet 51 toward the current collector 51a along the thickness direction H of the first electrode sheet 51. In two adjacent folding portions 511, the groove 5111a provided in one folding portion 511 is located on one side of the current collector 51a, and the groove 5111a provided in the other folding portion 511 is located on the other side of the current collector 51a. The groove 5111a may be formed by removing a portion of the electrode active material layer 51b on the first electrode sheet 51. Alternatively, when applying the electrode active material to the current collector 51a, less electrode active material is applied to the corresponding position to form the groove 5111a. In this embodiment, the depth of the groove 5111a along the thickness direction H may be equal to the thickness of the electrode active material layer 51b. The grooves 5111a extend to the surface of the current collector 51a but do not extend into the current collector 51a. However, as can be appreciated, the depth of the grooves 5111a may be less than the thickness of the electrode active material layer 51b, such that the grooves 5111a do not penetrate the electrode active material layer 51b along the thickness direction H, resulting in some additional electrode active material being provided between the grooves 5111a and the current collector 51a. In this embodiment, the depth of the grooves 5111a is less than the thickness of the electrode active material layer 51b, so that the current collector 51a is not damaged when the grooves 5111a are formed. The strength of the current collector 51a is not affected, as would be the case if the depth of the grooves 5111a were greater than the thickness of the electrode active material layer 51b (which would damage the current collector 51a). In this embodiment, the opening of the grooves 5111a is greater than the bottom of the grooves 5111a. In one example, the groove 5111a is projected in a V-shape on a plane perpendicular to the first direction X. However, the projection of the groove 5111a is not limited to a V-shape and may be a U-shape, a rectangle, or the like. Since the opening of the groove 5111a is equal to or greater than the bottom of the groove 5111a, on the one hand, this helps to ensure the folding position of the folding portion 511 and at the same time makes the groove 5111a easy to form. On the other hand, during the folding process, the electrode active material near the opening of the groove 5111a receives little or no pressing stress, so that the first laminated portion 512 receives less bending resistance, which makes it easier to fold it into a predetermined position more accurately.In this embodiment, the first electrode sheet 51 further has a weak region 5110 disposed at the folding portion 511, and the weak region 5110 is disposed corresponding to the groove 5111a along the thickness direction H of the first electrode sheet 51. The thickness of the first electrode sheet 51 at the weak region 5110 is smaller than the thickness of the region other than the weak region 5110 of the first electrode sheet 51. In this case, since the rigidity of the weak region 5110 is smaller than the rigidity of the region other than the weak region 5110 of the first electrode sheet 51, the folding portion 511 is easily folded at the weak region 5110, which helps to align the first outer edges 5121 located on the same side of two adjacent first laminated portions 512.

[0032] In the embodiment shown in FIGS. 5 and 6 , the thickness of the weakened region 5110 increases from the central region to both side regions along the extension direction W of the first electrode sheet 51. The grooves 5111a extend along the first direction X to the two opposing second outer edges 5112 of the folding portion 511, penetrating the entire folding portion 511. Compared to when the grooves 5111a do not penetrate the entire folding portion 511, the electrode active material near the grooves 5111a experiences less or no compressive stress during the folding process. This reduces the bending resistance of the first laminated portion 512, better ensuring the accuracy of the folding position of the folding portion 511 and further ensuring that the first laminated portion 512 can be folded more accurately into a predetermined position. In this embodiment, the folding portion 511 includes a portion of the electrode active material layer 51b. One of the two electrode active material layers 51b may not be completely removed in a portion corresponding to the weak region 5110, and the other layer may or may not be completely removed. In this embodiment, the opening dimension of the groove 5111a along the extension direction W of the first electrode sheet 51 is smaller than the dimension of the folding portion 511, so that the region of the folding portion 511 other than the guide portion 5111 is covered with the electrode active material layer 51b. In one example, both the two electrode active material layers 51b and the portion corresponding to the weak region 5110 are completely removed.

[0033] The dimension of the guide portion 5111 in the first direction X is set according to the dimension of the bending portion 511 in the first direction X. The dimension of the guide portion 5111 in the first direction X is also the length of the guide portion 5111. The dimension of the bending portion 511 in the first direction X is also the length of the bending portion 511. Therefore, in some other embodiments, the groove 5111a does not penetrate the bending portion 511 along the first direction X. The ratio of the dimension of the groove 5111a in the first direction X to the dimension of the bending portion 511 in the first direction X is 0.4 to 0.8, and preferably 0.4, 0.5, 0.6, 0.7, or 0.8.

[0034] FIG. 7 schematically illustrates the configuration of the first electrode sheet 51 according to the embodiment shown in FIG. 5 after multiple reciprocating folding. During the manufacturing process of the electrode assembly 50, the first electrode sheet 51 needs to be folded. During manufacturing, the guide portion 5111 guides the folding portion 511, i.e., the folding portion 511 can be folded along the guide portion 5111, thereby positioning the folding position at a predetermined position and helping to ensure that the first outer edges 5121 of two adjacent first laminated portions 512 coincide with each other. The folding portion 511 of the first electrode sheet 51 is folded along the folding direction Z shown in FIG. 7. The folding direction Z and the first direction X are perpendicular to each other; that is, the plane in which the folding direction Z lies is perpendicular to the first direction X. In this embodiment, the first electrode sheet 51 can be folded reciprocatingly into a substantially Z-shape. 7 does not indicate an entity structure, but merely indicates a separation line between the folding portion 511 and the first laminated portion 512. The two adjacent grooves 5111a are located on two opposing surfaces of the first electrode sheet 51, and the grooves 5111a are located on the side that receives compressive stress when the folding portion 511 is folded. Therefore, after the folding of the first electrode sheet 51 is completed, the openings of the grooves 5111a in the folding portion 511 face the space formed between the two adjacent first laminated portions 512. That is, the grooves 5111a are located on the inner surface of the folding portion 511. As a result, the side of the weak region 5110 adjacent to the grooves 5111a does not support tensile stress, reducing the possibility that the weak region 5110 will break due to the action of tensile stress. After the first electrode sheet 51 is folded, two adjacent first laminated portions 512 are stacked and disposed at a distance from each other along the second direction Y, and the space formed between the two adjacent first laminated portions 512 is used to accommodate the second laminated portion 521 of the second electrode sheet 52. The second direction Y is the same as the lamination direction of the first laminated portions 512 and is perpendicular to the first direction X. In this embodiment, the folded folded portion 511 has an arc shape, and may be, for example, an arc shape.

[0035] In the embodiment shown in FIG. 8 , a first electrode sheet 51 is used as a base, and separators 53 are installed on opposite sides of the first electrode sheet 51 in the thickness direction H of the first electrode sheet 51. The two separators 53 are installed as a pair, and the first electrode sheet 51 is installed between the two separators 53. The separators 53 cover the first stacked portion 512 and the folded portion 511. At least a portion of the tabs 50b extend beyond the edge of the separator 53 along the first direction X shown in FIG. 5 . During the manufacturing process, two separators 53 are attached to the first electrode sheet 51 by a corresponding material supply device. A second electrode sheet 52 is provided on the side of the separator 53 farther from the first electrode sheet 51. The polarities of the first electrode sheet 51 and the second electrode sheet 52 are opposite, and when one of them is a cathode sheet, the other is an anode sheet. The second electrode sheet 52 includes a plurality of second laminated portions 521. In this embodiment, two adjacent second laminated portions 521 are respectively disposed on opposite sides of the first electrode sheet 51. The first laminated portion 512 and the second laminated portion 521 are disposed corresponding to each other along the thickness direction H. In this embodiment, the second laminated portion 521 is disposed between two adjacent folded portions 511. However, this application is not limited to disposing the second laminated portion 521 between two adjacent folded portions 511, and a corresponding number of second laminated portions 521 may be disposed according to product requirements. In one example, after a separator 53 is disposed on the first electrode sheet 51, the second laminated portion 521 is attached to the separator 53. For example, the second laminated portion 521 and the separator 53 may be connected by thermocompression, electrophoresis, or adhesive bonding. The separator 53 is an insulator interposed between the first electrode sheet 51 and the second electrode sheet 52. The material of the separator 53 may be an insulating material such as plastic so as to insulate the first electrode sheet 51 and the second electrode sheet 52 from each other.

[0036] FIG. 9 is a schematic side view of an electrode assembly 50 according to an embodiment. The first electrode sheet 51, separator 53, and second electrode sheet 52 are assembled as shown in FIG. 8 , and then the folding portion 511 is folded along the guide portion 5111, resulting in the folded state shown in FIG. 9 . In the second direction Y, a second laminated portion 521 is disposed between two adjacent first laminated portions 512, thereby alternating the first laminated portions 512 and the second laminated portions 521. In the second direction Y, the folding portion 511 and the second laminated portion 521 do not overlap with each other. In this embodiment, the folding portion 511 is completely folded, and the starting line of the folding portion 511 is the area where folding begins relative to the first laminated portion 512. A gap is formed between the folded portion 511 and the second laminate portion 521, and both edges of the first laminate portion 512 along the extension direction W extend beyond the second laminate portion 521. The second laminate portion 521 does not contact the folded portion 511 toward the end of the folded portion 511 along the extension direction W. This reduces the possibility of the end of the second laminate portion 521 interfering with the folded portion 511, causing powder shedding or detachment of the electrode active material. After the first electrode sheet 51 is folded, the grooves 5111a of each folded portion 511 are located on the inner surface of the folded portion 511. That is, after the first electrode sheet 51 is folded, the grooves 5111a of each folded portion 511 are located on the side of the current collector 51a that is closest to the second laminate portion 521. Here, the inner surface refers to the surface of the folded portion 511 that is closest to the second laminate portion 521. Correspondingly, the outer surface of the folding portion 511 refers to the surface of the folding portion 511 that is farther away from the second stacked portion 521. In this embodiment, the guide portion 5111 of the folding portion 511 is disposed corresponding to the middle region of the second stacked portion 521.

[0037] 10 is a schematic diagram illustrating a planar structure in which a first laminated portion 512 and a second laminated portion 521 are stacked on top of each other. In this embodiment, the first electrode sheet 51 is an anode sheet, and the second electrode sheet 52 is a cathode sheet. Due to the guiding action of the guide portion 5111 at the folding portion 511, after the first electrode sheet 51 is folded back and forth, all edges of the first laminated portion 512 extend beyond the second laminated portion 521. This ensures that the entire second laminated portion 521 is covered by the first laminated portion 512, effectively reducing the possibility of lithium deposition occurring due to the second laminated portion 521 extending beyond the first laminated portion 512. Here, being entirely covered by the first stacked portion 512 means that the orthogonal projection of the second stacked portion 521 in the second direction Y is completely located within the orthogonal projection of the first stacked portion 512 in the second direction Y, and at this time, the projected area of ​​the second stacked portion 521 is smaller than the projected area of ​​the first stacked portion 512. In one example, the distance between the first outer edge 5121 of the first stacked portion 512 and the corresponding third outer edge 5211 of the second stacked portion 521 is 0.2 mm or more and 5 mm or less, and is preferably 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, or 4.5 mm. Because the guide portion 5111 is installed at the folding portion 511, the first electrode sheet 51 is folded under the guiding action of the guide portion 5111, so that the first outer edges 5121 of two adjacent first laminated portions 512 connected to the folding portion 511 coincide with each other, i.e., the two first outer edges 5121 located on the same side of the two adjacent first laminated portions 512 have an included angle α. Here, the coincidence of the first outer edges 5121 of two adjacent first laminated portions 512 includes the state shown in FIG. 10 , i.e., the projections of the two adjacent first laminated portions 512 overlap each other along the second direction Y. The included angle α of the two first outer edges 5121 located on the same side of the two adjacent first laminated portions 512 is 0°, so that the first outer edges 5121 of the two adjacent first laminated portions 512 are aligned and coincident with each other in a planar state.The state shown in FIG. 11 also includes the state where the first outer edges 5121 of two adjacent first laminated portions 512 are aligned. FIG. 11 schematically illustrates another planar structure in which a first laminated portion 512 and a second laminated portion 521 are stacked on top of each other. The two first outer edges 5121 of two adjacent first laminated portions 512 located on the same side in a planar view are not perfectly aligned. An included angle α exists between the two first outer edges 5121 of two adjacent first laminated portions 512 located on the same side. The included angle α is greater than 0° and less than or equal to 30°, ensuring that the first laminated portion 512 covers the second laminated portion 521. Preferably, the value of the included angle α is 5°, 10°, 15°, 20°, or 25°. Here, the included angle α is a tolerance angle. If the first outer edge 5121 of a first laminated portion 512 after being folded cannot be shifted and overlap with the first outer edge 5121 of another first laminated portion 512, but can still ensure that the first laminated portion 512 covers the second laminated portion 521, the included angle α between the two first outer edges 5121 located on the same side of two adjacent first laminated portions 512 is called the tolerance angle.

[0038] In the first electrode sheet 51 according to the embodiment of the present application, the guide portion 5111 is provided at the folding portion 511. Therefore, when the first electrode sheet 51 is folded during the manufacturing process of the electrode assembly 50, the guide portion 5111 facilitates folding of the first electrode sheet 51 in the region of the folding portion 511. Thus, providing the guide portion 5111 improves the controllability and accuracy of the folding position of the folding portion 511. This also improves the alignment of the first outer edges 5121 of two adjacent first laminate portions 512. This reduces the possibility that one of the first laminate portions 512 and the second laminate portion 521, acting as the negative electrode, will not completely cover the other, acting as the positive electrode, due to randomness in the folding position after the first electrode sheet 51 is folded, thereby reducing the possibility of lithium deposition occurring in the processed electrode assembly 50. Furthermore, the electrode active material layer 51b itself coated on the current collector 51a has a certain degree of brittleness. During the bending process of the bending portion 511, the electrode active material layer 51b is subjected to an external force, which may cause the electrode active material layer 51b to peel off or powder off from the current collector 51a, affecting the electrochemical performance and safety of the electrode assembly 50. The grooves 5111a of the present application are formed in a manner that reduces the corresponding electrode active material, thereby helping to reduce internal stress applied to the corresponding electrode active material layer 51b during the bending process of the bending portion 511, and reducing the possibility of the electrode active material layer 51b peeling off or powder off.

[0039] 7 and 9 will not be described here, and differences from the embodiments shown in Figures 7 and 9 will be mainly described here. In these embodiments, of two adjacent folding portions 511, one groove 5111a is located on one surface of the first electrode sheet 51, and the other groove 5111a is located on the other surface of the first electrode sheet 51. Therefore, after folding, the first electrode sheet 51 has the guide portion 5111 in the folding portion 511 facing away from the space formed between the two adjacent first laminate portions 512, i.e., located on the outer surface of the folding portion 511. As a result, the groove 5111a is located on the side that receives tensile stress when the folding portion 511 is bent.

[0040] 9 。 In other embodiments, the same structure as the embodiment shown in FIG. 9 will not be described here, and differences from the embodiment shown in FIG. 9 will be mainly described here. In these embodiments, a guide portion 5111 is provided in each folding portion 511. The grooves 5111a of the guide portions 5111 of two adjacent folding portions 511 are located on the same surface of the first electrode sheet 51. Therefore, in the folded first electrode sheet 51, the groove 5111a in one folding portion 511 of the two adjacent folding portions 511 is located on the outer surface of the folding portion 511 and faces away from the space formed between the two adjacent first laminated portions 512, while the groove 5111a in the other folding portion 511 is located on the inner surface of the folding portion 511 and faces the space formed between the two adjacent first laminated portions 512. In this embodiment, when processing and manufacturing the first electrode sheet 51, it is only necessary to process each groove 5111a on the same surface of the first electrode sheet 51, which helps to reduce the difficulty of processing the first electrode sheet 51.

[0041] FIG. 12 is a schematic diagram illustrating a side structure of an electrode assembly 50 according to another embodiment of the present disclosure. In some of the other embodiments shown in FIG. 12, the same structures as those in the embodiment shown in FIG. 9 will not be described here, and differences from the embodiment shown in FIG. 9 will be mainly described. In this embodiment, a guide portion 5111 is provided corresponding to each folding portion 511. Each guide portion 5111 includes two grooves 5111a. When the first electrode sheet 51 is in an unfolded state, the two grooves 5111a are provided corresponding to each other along the thickness direction H of the first electrode sheet 51. In the folded first electrode sheet 51, one of the two grooves 5111a is provided on the outer surface of the folding portion 511 and faces away from the space formed between two adjacent first laminated portions 512, and the other is provided on the inner surface of the folding portion 511 and faces the space formed between two adjacent first laminated portions 512. In this embodiment, two grooves 5111a are formed in each folding portion 511 in the thickness direction H, which reduces the thickness of the weakened region 5110, thereby further reducing the rigidity of the weakened region 5110. Because the rigidity of the weakened region 5110 corresponding to the two grooves 5111a is reduced, the folding portion 511 is easier to fold in the area of ​​the weakened region 5110 where the grooves 5111a are formed, further improving the controllability and accuracy of the folding position. Compared to a folding portion 511 without grooves 5111a, the electrode active material layers 51b on both sides of this embodiment experience relatively smaller internal stress when folded, further reducing the difficulty of folding and the possibility of the electrode active material layers 51b falling off or powdering from the current collector 51a due to tensile or compressive stress. In one example, the two grooves 5111a have the same structure.

[0042] In some other embodiments, the same structures as those in the embodiment shown in FIG. 9 will not be described here, and differences from the embodiment shown in FIG. 9 will be mainly described. In these embodiments, the guide portion 5111 includes a groove 5111a. The groove 5111a extends from the inner surface of the folded portion 511 toward the current collector 51a. The opening of the groove 5111a faces the second laminated portion 521. The groove 5111a penetrates the inner electrode active material layer 51b and a portion of the current collector 51a in the thickness direction H of the first electrode sheet 51. In one example, the groove 5111a is formed using at least one of a metal cutter, a laser cutter, and a liquid etching tool. Therefore, in these embodiments, forming a portion of the groove 5111a in the current collector 51a ensures that the electrode active material in the corresponding region is removed, while also reducing the processing accuracy requirements and processing difficulty. In addition, a portion of the current collector 51a is removed to form a part of the groove 5111a, which further reduces the rigidity of the weak region 5110 located corresponding to the groove 5111a, making it easier for the folding portion 511 to bend at the guide portion 5111. In another embodiment, the groove 5111a extends from the folding portion 511 toward the current collector 51a, facing away from the outer surface of the second laminate portion 521. The opening of the groove 5111a is located on the outer surface of the folding portion 511, so that the opening of the groove 5111a faces away from the second laminate portion 521. The groove 5111a penetrates the outer electrode active material layer 51b and a part of the current collector 51a along the thickness direction H of the first electrode sheet 51.

[0043] FIG. 13 schematically illustrates the structure of a first electrode sheet 51 according to another embodiment of the present invention after being folded back and forth multiple times. FIG. 14 schematically illustrates the side structure of an electrode assembly 50 according to another embodiment of the present invention. The first electrode sheet 51 in the embodiment shown in FIG. 14 is the first electrode sheet 51 according to the embodiment shown in FIG. 13. In the embodiment shown in FIGS. 13 and 14, the same structure as in the embodiment shown in FIG. 9 will not be described here, and differences from the embodiment shown in FIG. 9 will be mainly described here. In this embodiment, the guide portion 5111 includes one groove 5111a. The groove 5111a is recessed and extends from the inner surface of the folded portion 511 toward the current collector 51a. The opening of the groove 5111a faces the second laminate portion 521. The groove 5111a penetrates the inner electrode active material layer 51b along the thickness direction H of the first electrode sheet 51, and the dimension of the groove 5111a along the extension direction W of the first electrode sheet 51 is equal to the dimension of the folding portion 511. The portion of the inner electrode active material layer 51b corresponding to the folding portion 511 is entirely removed, thereby exposing the surface of the current collector 51a facing the second laminate portion 521. The portion of the outer electrode active material layer 51b corresponding to the folding portion 511 is left entirely unremoved. Since the inner electrode active material layer 51b at the folding portion 511 is entirely removed, the rigidity of the folding portion 511 is further reduced, making it easier to fold the folding portion 511 at the guide portion 511 and effectively preventing the inner electrode active material layer 51b from falling off or powdering after the folding portion 511 is folded. In some other embodiments, a portion of the outer electrode active material layer 51b corresponding to the bent portion 511 may be removed, so that the guide portion 5111 is also formed in the outer electrode active material layer 51b.

[0044] In some other embodiments, the same structure as the embodiment shown in FIG. 14 will not be described here, and differences from the embodiment shown in FIG. 14 will be mainly described here. In these embodiments, the guide portion 5111 includes one groove 5111a. The groove 5111a extends from the outer surface of the folded portion 511 toward the current collector 51a. The opening of the groove 5111a faces away from the second laminate portion 521. The groove 5111a penetrates the outer electrode active material layer 51b along the thickness direction H of the first electrode sheet 51, and the dimension of the groove 5111a is equal to the dimension of the folded portion 511 along the extension direction W of the first electrode sheet 51. The portion of the outer electrode active material layer 51b corresponding to the folded portion 511 is entirely removed, thereby exposing the surface of the current collector 51a facing away from the second laminate portion 521. The portion of the inner electrode active material layer 51b corresponding to the folded portion 511 remains intact. In some other embodiments, a portion of the inner electrode active material layer 51b corresponding to the bending portion 511 may be removed, thereby forming a groove 5111a in the inner electrode active material layer 51b. Since the outer electrode active material layer 51b at the bending portion 511 is entirely removed, the rigidity of the bending portion 511 is further reduced, making it easier for the bending portion 511 to bend at the guide portion 5111 and effectively preventing the outer electrode active material layer 51b from falling off or powdering after the bending portion 511 is bent.

[0045] FIG. 15 schematically illustrates the structure of a first electrode sheet 51 according to another embodiment of the present application after multiple reciprocal folding. In the embodiment illustrated in FIG. 15, the same structure as in the embodiment illustrated in FIG. 7 will not be described here, and differences from the embodiment illustrated in FIG. 7 will be mainly described. In this embodiment, the guide portion 5111 includes two or more grooves 5111a. The two or more grooves 5111a are spaced apart along the first direction X. In this embodiment, when the first electrode sheet 51 is in an unfolded state, weak regions 5110 are disposed corresponding to the grooves 5111a along the thickness direction H of the first electrode sheet 51. The number and positions of the weak regions 5110 correspond one-to-one to the number and positions of the grooves 5111a. In this embodiment, the projection of the grooves 5111a onto a plane perpendicular to the first direction X may be triangular. However, the projection of the grooves 5111a is not limited to a triangle and may be a trapezoid, a rectangle, or the like. Each groove 5111a extends from the outer surface of the bent portion 511 toward the current collector 51a, so that the opening of the groove 5111a faces away from the second laminate portion 521. The ratio of the sum of the dimensions of each groove 5111a in the first direction X to the dimension of the bent portion 511 in the first direction X is 0.4 to 0.8, and preferably 0.4, 0.5, 0.6, 0.7, or 0.8. In some other embodiments, each groove 5111a extends from the inner surface of the bent portion 511 toward the current collector 51a, so that the opening of the groove 5111a faces the second laminate portion 521. In some other embodiments, a plurality of grooves 5111a are provided on each of the inner surface and the outer surface of the bent portion 511. In one example, when the first electrode sheet 51 is in an unfolded state, the positions of the grooves 5111a on the inner surface and the grooves 5111a on the outer surface correspond to each other along the thickness direction H of the first electrode sheet 51. The positions of the weak regions 5110 correspond one-to-one to the positions of the grooves 5111a on the inner surface and the grooves 5111a on the outer surface. The grooves 5111a on the inner surface and the grooves 5111a on the outer surface both correspond to the weak regions 5110.

[0046] FIG. 16 schematically illustrates the structure of a first electrode sheet 51 according to another embodiment of the present application after multiple reciprocal folding. In the embodiment illustrated in FIG. 16, the same structure as in the embodiment illustrated in FIG. 7 will not be described here, and differences from the embodiment illustrated in FIG. 7 will be mainly described. In this embodiment, the guide portion 5111 includes two or more through holes 5111b. The two or more through holes 5111b are spaced apart along the first direction X. When the first electrode sheet 51 is in an unfolded state, the through holes 5111b penetrate the two electrode active material layers 51b and the current collector 51a along the thickness direction H of the first electrode sheet 51. When the first electrode sheet 51 is in an unfolded state, the dimension of the through holes 5111b in the extension direction W of the first electrode sheet 51 is smaller than the dimension of the folding portion 511 in the extension direction W of the first electrode sheet 51. In one example, the shape of the through holes 5111b may be rectangular, square, elliptical, trapezoidal, or triangular. In this embodiment, the ratio of the sum of the dimensions of the through holes 5111b in the first direction X to the dimension of the bent portion 511 in the first direction X is 0.4 to 0.8, and preferably 0.6 or 0.7.

[0047] In this embodiment, the guide portion 5111 includes one through hole 5111b. The ratio of the dimension of the through hole 5111b in the first direction X to the dimension of the bent portion 511 in the first direction X is 0.4 to 0.8, and preferably 0.6 or 0.7.

[0048] 17 is a schematic diagram illustrating a side cross-sectional structure of an electrode assembly 50 according to another embodiment of the present application. The first electrode sheet 51 included in the electrode assembly 50 is the first electrode sheet 51 according to the embodiment shown in FIG. 16. In this embodiment, the through-hole 5111b in the folded portion 511 is disposed corresponding to the intermediate region of the second laminated portion 521. However, the present application does not limit the position of the through-hole 5111b, and the through-hole 5111b may be disposed corresponding to another region of the second laminated portion 521 that is shifted from the intermediate region along the second direction Y.

[0049] FIG. 18 schematically illustrates the structure of a first electrode sheet 51 according to another embodiment of the present disclosure after multiple reciprocal folding. In the embodiment illustrated in FIG. 18, the same structure as in the embodiment illustrated in FIG. 7 will not be described here, and differences from the embodiment illustrated in FIG. 7 will be mainly described. In this embodiment, the guide portion 5111 includes two or more grooves 5111a and two or more through holes 5111b. One or more grooves 5111a may be disposed between two adjacent through holes 5111b along the first direction X. Alternatively, one or more through holes 5111b may be disposed between two adjacent grooves 5111a. In some other embodiments, the guide portion 5111 may include other numbers of grooves 5111a and other numbers of through holes 5111b as needed. In one example, the guide portion 5111 may include one groove 5111a and one through hole 5111b. 18 , in two adjacent folded portions 511, in one folded portion 511, each groove 5111a extends from the outer surface of folded portion 511 toward current collector 51a, such that the opening of groove 5111a faces away from second laminate portion 521. In the other folded portion 511, each groove 5111a extends from the inner surface of folded portion 511 toward current collector 51a, such that the opening of groove 5111a faces away from second laminate portion 521. As can be understood, in other embodiments, each groove 5111a in each folded portion 511 extends from the outer surface of folded portion 511 toward current collector 51a, such that the opening of groove 5111a faces away from second laminate portion 521. Alternatively, each groove 5111 a in each bent portion 511 extends from the outer surface of the bent portion 511 toward the current collector 51 a, so that the opening of the groove 5111 a faces the second stacked portion 521 .

[0050] FIG. 19 is a schematic diagram illustrating a side structure of an electrode assembly 50 according to another embodiment of the present invention. In the embodiment illustrated in FIG. 19, the same structure as that of the embodiment illustrated in FIG. 9 will not be described here, and differences from the embodiment illustrated in FIG. 9 will be mainly described. In this embodiment, a bent portion 511 includes two connecting portions 511a and an intermediate transition portion 511b connecting the two connecting portions 511a. The intermediate transition portion 511b is substantially perpendicular to the connecting portions 511a, and the intermediate transition portion 511b is substantially perpendicular to the first laminated portion 512. The two connecting portions 511a of the bent portion 511 are respectively connected to two adjacent first laminated portions 512. As illustrated in FIG. 19, the connecting portions 511a are flush with the first laminated portions 512. Each bent portion 511 is provided with two guide portions 5111. When the first electrode sheet 51 is in an unfolded state, the two guide portions 5111 are spaced apart from each other along the extending direction W of the first electrode sheet 51. A portion of each guide portion 5111 is located at the connecting portion 511a, and the other portion is located at the intermediate transition portion 511b. In this embodiment, both guide portions 5111 are located on the inner surface of the folding portion 511. The inner side of the intermediate transition portion 511b has a portion of the electrode active material layer 51b. In this embodiment, when the first electrode sheet 51 is folded, it is easy to fold it to positions corresponding to the two guide portions 5111, which further improves the controllability and accuracy of the folding position and ensures that the first outer edges 5121 of two adjacent first laminate portions 512 are aligned.

[0051] FIG. 20 schematically illustrates the side structure of an electrode assembly 50 according to another embodiment of the present application. In the embodiment illustrated in FIG. 20, the same structure as in the embodiment illustrated in FIG. 9 will not be described here, and differences from the embodiment illustrated in FIG. 9 will be mainly described here. In this embodiment, the separator 53 extends beyond the first electrode sheet 51, and the portion of the separator 53 that extends beyond the first electrode sheet 51 surrounds and covers the first electrode sheet 51 and the second electrode sheet 52. This allows the separator 53 to directly provide insulating protection for the first electrode sheet 51 and the second electrode sheet 52, thereby eliminating the need for a subsequent process of insulating and sealing the folded first electrode sheet 51 and the second electrode sheet 52 again.

[0052] An electrode assembly 50 according to an embodiment of the present application includes a first electrode sheet 51, a second electrode sheet 52, and a separator 53. The first electrode sheet 51 has first stacking portions 512 and folding portions 511 arranged alternately. The folding portions 511 have guide portions 5111. In the manufacturing process of the electrode assembly 50, the separator 53 and the second electrode sheet 52 must be sequentially placed on the first electrode sheet 51, and then the first electrode sheet 51 is folded back and forth multiple times, so that the first stacking portion 512 and the second stacking portion 521 of the second electrode sheet 52 are stacked together. The guide portion 5111 of the folding portion 511 can guide the first electrode sheet 51 to be folded at a predetermined position of the folding portion 511 during the folding process of the first electrode sheet 51, thereby improving the controllability and accuracy of the folding position of the first electrode sheet 51 and further ensuring that the first outer edge 5121 of the first laminated portion 512 is aligned, thereby allowing one of the first laminated portion 512 and the second laminated portion 521, acting as a cathode sheet, to cover the other of the first laminated portion 512 and the second laminated portion 521, acting as an anode sheet. As such, the electrode assembly 50 according to the embodiment of the present application is less likely to experience lithium deposition between the first electrode sheet 51 and the second electrode sheet 52, ensuring that a secondary battery using the electrode assembly 50 has good electrochemical and safety performance.

[0053] The present embodiment further includes: providing a first electrode sheet (51) including a plurality of folding portions (511) and a plurality of first laminated portions (512), each folding portion (511) being used to connect two adjacent first laminated portions (512), wherein the folding portion (511) has a guide portion (5111); providing a second electrode sheet 52 having an opposite polarity to the first electrode sheet 51, the second electrode sheet 52 including a plurality of second laminated portions 521, each second laminated portion 521 being disposed between two adjacent first laminated portions 512; and a step of folding the folding portion 511 along the guide portion 5111 so that the first outer edges 5121 of two adjacent first laminated portions 512 connected to the folding portion 511 coincide with each other.

[0054] The method for forming the electrode assembly 50 according to the embodiment of the present invention can be used to manufacture the electrode assembly 50 according to each of the above embodiments.

[0055] In one embodiment, the forming method further includes a step of forming the guide portion 5111 using at least one of a metal cutter, a laser cutter, and a liquid etching tool. In one example, in this step, the guide portion 5111 is formed on the first electrode sheet 51 by removing the electrode active material layer 51b at a predetermined position in the folded portion 511 by a method such as mechanical cutting, laser cutting, water jet erosion, or chemical reaction.

[0056] In one embodiment, before the step of providing a second electrode sheet 52 having an opposite polarity to the first electrode sheet 51, a separator 53 is provided that is paired with the first electrode sheet 51 having a guide portion 5111, and the paired separators 53 are positioned on opposite sides of the first electrode sheet 51.

[0057] In the manufacturing process of the electrode assembly 50, the forming method of the electrode assembly 50 of the present application folds the first electrode sheet 51 along the guide portion 5111 of the folding portion 511. The guide portion 5111 of the folding portion 511 can guide the first electrode sheet 51 so that it is folded at a predetermined position of the folding portion 511 during the folding process of the first electrode sheet 51, thereby improving the controllability and accuracy of the folding position of the first electrode sheet 51, so that the first outer edges 5121 of two adjacent first laminated portions 512 connected to the folding portion 511 coincide with each other, and one of the first laminated portion 512 and the second laminated portion 521, serving as a cathode sheet, covers the other as an anode sheet. As such, the electrode assembly 50 manufactured using the method for forming the electrode assembly 50 according to the embodiment of the present application is less likely to experience lithium deposition between the first electrode sheet 51 and the second electrode sheet 52, ensuring that a secondary battery using the electrode assembly 50 has good electrochemical and safety performance.

[0058] In the present embodiment, the electrode assembly 50 may be a stacked battery cell formed by stacking a first electrode sheet 51, a separator 53, and a second electrode sheet 52. The first electrode sheet 51 includes a plurality of folded portions 511 and a plurality of first laminated portions 512, where the folded portions 511 are in an at least partially folded state after being folded. The first electrode sheet 51 has a continuous extending structure as a whole. The folded portions 511 and the first laminated portions 512 are alternately arranged along the extending direction W of the first electrode sheet 51 itself. The second electrode sheet 52 includes a plurality of second laminated portions 521, where each second laminated portion 521 is arranged between two adjacent first laminated portions 512. In the following embodiments, the first electrode sheet 51 is exemplarily described as an anode sheet and the second electrode sheet 52 is exemplarily described as a cathode sheet. Similarly, in another embodiment, the first electrode sheet 51 may be a cathode sheet and the second electrode sheet 52 may be an anode sheet. The guide portion 5111 may be a mark formed on the first electrode sheet 51.

[0059] To better understand the present invention, a battery cell stack manufacturing system and a battery cell stack molding method according to an embodiment of the present invention will be described in detail below with reference to FIGS.

[0060] The present embodiment is a first conveying mechanism (100) for providing an anode sheet, the anode sheet including a plurality of folding portions (511) and a plurality of first stacking portions (512), each folding portion (511) being used to connect two adjacent first stacking portions (512); a mark forming mechanism 300 used to form a mark on the folding portion 511 to guide the folding portion 511 during manufacturing; a second conveying mechanism (400) for providing a cathode sheet having an opposite polarity to the anode sheet, the cathode sheet including a plurality of second stacked portions (521), each second stacked portion (521) being disposed between two adjacent first stacked portions (512); and a stacking mechanism 600 used to fold the folding portion 511 along the trace and stack two adjacent first stacked portions 512 connected to the folding portion 511.

[0061] 21 , a manufacturing system for stacked battery cells provided by an embodiment of the present application includes a first conveying mechanism 100, a separator conveying mechanism 200, a trace forming mechanism 300, a second conveying mechanism 400, a combining mechanism 500, and a stacking mechanism 600. The first conveying mechanism 100 is for providing an anode sheet. The separator conveying mechanism 200 is located downstream of the first conveying mechanism 100 and is used to provide a pair of separators 53, which are used to sandwich the anode sheet. The trace forming mechanism 300 is located upstream of the separator conveying mechanism 200, and in some alternative examples, the trace forming mechanism 300 can be located between the first conveying mechanism 100 and the separator conveying mechanism 200, and is used to form a trace on the anode sheet. The second conveying mechanism 400 is provided downstream of the separator conveying mechanism 200 and is used to provide a plurality of cathode sheets to the separator 53. The combining mechanism 500 is provided downstream of the second conveying mechanism 400 and is used to combine the anode sheets, the separator 53, and the cathode sheets to form a stacked assembly. The stacking mechanism 600 is provided downstream of the combining mechanism 500 and is used to stack the stacked assemblies back and forth along a trace to form a stacked battery cell.

[0062] Note that the terms "upstream" and "downstream" mentioned above and below in this application refer to the order in which the stacked battery cells are manufactured, and do not limit the spatial positions between the respective components.

[0063] Furthermore, the traces referred to above and below in this application refer to marks or impressions left on an object, such as creases, and alternatively, they can refer to structures formed at the removed portions of material after removing some material from the anode sheet with a material removing member.

[0064] The stacked battery cell manufacturing system provided by the embodiments of the present application can meet the manufacturing demands of stacked battery cells and reduce the safety hazards of stacked battery cells.

[0065] 22 , the first conveying mechanism 100 may optionally include a first unwinding device 101, a first belt connecting device 102, a first tension balancing device 103, and a first deviation calibrating device 104. The first deviation calibrating device 104 is installed downstream of the first unwinding device 101, and the first belt connecting device 102 and the first tension balancing device 103 are both located between the first unwinding device 101 and the first deviation calibrating device 104.

[0066] The first unwinding device 101 includes a first unwinding roll and a driving member that drives the first unwinding roll to rotate, and the anode sheet is wound around the first unwinding roll, and the rotation of the first unwinding roll achieves the release of the anode sheet.

[0067] Optionally, the first belt connecting device 102 may be installed downstream of the first unwinding device 101, and when the unwinding of the anode sheet is completed, the connecting belt can be performed by this mechanism to ensure continuous production.

[0068] Optionally, the first deviation calibration device 104 is located upstream of the trace forming mechanism 300, and monitors whether the anode sheet is within a predetermined range of the trace forming mechanism 300 in real time or at regular time intervals using a detection device; if it is not within the predetermined range, the position of the anode sheet needs to be adjusted, and further ensure that the anode sheet is always within the trace forming range of the trace forming mechanism 300.

[0069] Optionally, a first tension balancing device 103 can be located downstream of the first belt connecting device 102, and if the first unwinding device 101 and the drive motor for providing driving power to the anode sheet are not synchronized, the first tension balancing device 103 can adjust and maintain the tension of the anode sheet within a certain range.

[0070] 23 and 25 , in some alternative embodiments, the trace-forming mechanism 300 includes a first trace-forming member 301 and a second trace-forming member 302 spaced apart from each other. The first trace-forming member 301 is used to form a trace on one surface of the anode sheet in the thickness direction H of the anode sheet, and the second trace-forming member 302 is used to form a trace on the other surface of the anode sheet. This arrangement allows the trace-forming mechanism 300 to alternately form traces on the two surfaces of the anode sheet in the thickness direction H when it operates, allowing the anode sheet to be smoothly folded along the traces on the two surfaces during final lamination. The traces align with the direction of the final fold marks, which helps the lamination mechanism 600 to reciprocate and stack the assemblies to be laminated according to the traces.

[0071] In one alternative embodiment, the first trace-forming member 301 is one of a metal cutter, a laser cutter, and a liquid etching tool, and the first trace-forming member 301 of the above form can form traces on one surface of the anode sheet in the thickness direction H by removing material at predetermined locations using methods such as mechanical cutting, laser cutting, water jet erosion, or chemical reaction. This simple operation process makes it easy to form traces.

[0072] Similarly, in some alternative examples, in the manufacturing system for stacked battery cells according to the above embodiments, the second trace-forming member 302 is one of a metal cutter, a laser cutter, and a liquid etching tool, and the above-mentioned second trace-forming member 302 can form traces on other surfaces in the thickness direction H of the anode sheet by removing material at predetermined locations using methods such as mechanical cutting, laser cutting, water jet erosion, or chemical reaction. This simple operation process makes it easy to form the traces.

[0073] In one alternative embodiment, a first dust remover 105 is installed downstream of the mark forming mechanism 300, and is located between the mark forming mechanism 300 and the separator conveying mechanism 200. The first dust remover 105 removes dust from the front and / or rear surfaces of the anode sheets, thereby cleaning the anode sheets. The first dust remover 105 may include a brush and a dust collector. The brush can be used to remove dust as the anode sheets move, and the dust collector can be used to suck and collect the dust removed from the anode sheets. This ensures the cleanliness of the anode sheets when they are sandwiched between the separators 53, and further optimizes the electrical performance of the stacked battery cells formed by stacking them.

[0074] In some alternative embodiments, the separator transport mechanism 200 may be further located downstream of the second trace forming member 302 of the trace forming mechanism 300, and the separator transport mechanism 200 may include separator transport devices installed as a pair, and the two separator transport devices in the same pair may be installed opposite each other. Each separator transport device includes a separator unwinding roll 21 and a drive member that drives the separator unwinding roll to rotate, and the separator 53 is wound around the separator unwinding roll, and the rotation of the separator unwinding roll realizes the release of the separator 53, and the guide wheel guides the corresponding separator 53 to a predetermined position so that the anode sheet having the trace can be sandwiched between them.

[0075] As shown in FIG. 25, in some optional embodiments, the second conveying mechanism 400 may include a second unwinding device 401, a second belt connecting device 402, a second tension balancing device 403, a second deviation correction device 404, a cutting device 405, and a second dust removal device 406.

[0076] Optionally, the second unwinding device 401 includes a second unwinding roll and a driving member that drives the second unwinding roll to rotate, and the cathode sheet is wound around the second unwinding roll, and the rotation of the second unwinding roll realizes the release of the cathode sheet.

[0077] Optionally, a second belt connecting device 402 may be installed downstream of the second unwinding device 401, and when the unwinding of the cathode sheet is completed, the connecting belt can be performed by this mechanism to ensure continuous production.

[0078] Optionally, a second tension balance device 403 is located downstream of the second belt connecting device 402. If the second unwinding device 401 and the drive motor for providing driving power to the cathode sheet are not synchronized, the second tension balance device 403 can make adjustments to maintain the tension of the cathode sheet within a certain range. Optionally, a second deviation calibration device 404 is located downstream of the second tension balance device 403. A detection device monitors whether the cathode sheet is within a predetermined range of the second deviation calibration device 404 in real time or at regular time intervals. If it is not within the predetermined range, the position of the cathode sheet needs to be adjusted, and further, the cathode sheet must always be within the cutting range of the cutting mechanism 45.

[0079] Optionally, a cutting device 405 is installed downstream of the second deviation calibrating device 404 and is used to cut the strip-shaped cathode sheet into a plurality of block-shaped structures of a predetermined size.

[0080] Optionally, the second dust removal device 406 is located downstream of the cutting device 405 and is used to receive and remove dust from the lumps of cathode sheets to ensure the cleanliness of the cathode sheets connected to the separators 53. The second dust removal device 406 may include a belt brush 4061 and a dust suction device 4062. The cathode sheets cut by the cutting device 405 fall onto the belt brush 4061 of the second dust removal device 406, which then transports the cathode sheets toward the combining mechanism 500 and connects them to the separators 53. During the transport process, the belt brush 4061 can peel off dust from the cathode sheets and the dust suction device 4062 can suck and collect it, ensuring the cleanliness of the cathode sheets connected to the separators 53 and enabling the manufactured stacked battery cells to better meet their electrical requirements.

[0081] In specific implementation, the second conveying mechanisms 400 can be installed in pairs according to needs, and the second conveying mechanisms 400 installed in pairs can provide cathode sheets to the same separator 53 or different separators 53 relatively synchronously or alternately.

[0082] 26 to 28, optionally, in the stacked battery cell manufacturing system provided by each of the above embodiments, its combining mechanism 500 can include a heating and conveying assembly 501 and a roller pressing member 502. The heating and conveying assembly 501 is used to heat and convey the separator 53 and cathode sheet, and the roller pressing member 502 is installed downstream of the heating and conveying assembly 501 and uses a roller to press the separator 53 and cathode sheet after heating, thereby combining and connecting them. By adopting the above structural form, the combining mechanism 500 has a simple structure and can ensure the combined effect between the separator 53 sandwiching the cathode sheet and the anode sheet.

[0083] In one alternative embodiment, the heating and conveying assembly 501 includes a heating member 5011 and a conveying member 5012. The heating member 5011 is for heating the separator 53 and the cathode sheet. The conveying member 5012 includes a transmission wheel 5012a and a transmission belt 5012b engaged with the transmission wheel 5012a. The transmission belt 5012b is installed surrounding the heating member 5011 and is used to convey the separator 53 and the cathode sheet.

[0084] The cathode sheet is coated with a PVDF adhesive, and the corresponding separator 53 is also coated with a PVDF adhesive, so that the adhesives on both sheets can be pressed together after heating to better bond them together.

[0085] Therefore, the heating and conveying assembly 501 employs the above structure, so that it can meet the heating and bonding requirements, and the conveying member 5012 is limited to include a transmission wheel 5012a and a transmission belt 5012b engaged with the transmission wheel 5012a. By limiting the relationship between the transmission belt 5012b and the heating member 5011, not only can it meet the heating requirements, but also the transmission belt 5012b can protect and convey the cathode sheet located on the surface of the separator 53, so that the cathode sheet moves synchronously with the separator 53, ensuring the stability of their relative positions and further ensuring the composite requirements between the cathode sheet and the separator 53.

[0086] Furthermore, in the stacked battery cell manufacturing system provided by the embodiment of the present application, the heating and conveying assembly 501 employs the above-described structure, so that after the cathode sheet is sufficiently heated by the heating element 5011, the cathode sheet and the separator 53 are connected together by the roller pressing element 502, thereby achieving the purpose of manufacturing a stacked assembly. Compared to the conventional combining mechanism 500, the heating and conveying assembly 501 uses a transmission belt instead of disposable PET film, thereby eliminating the need for PET film, further reducing the time required for unwinding and rewinding the PET film, improving equipment utilization rate, and reducing manufacturing costs.

[0087] In some alternative embodiments, the heating element 5011 may be an oven, a heat exchanger, or other element capable of providing heat energy, thereby completing heating at least to the cathode sheet and the separator 53.

[0088] In some alternative embodiments, when the heating element 5011 adopts an oven structure, the oven is made of a metal plate and has multiple heating tubes uniformly arranged inside. The heating tubes heat the oven to a set temperature, and when the cathode sheet passes through the oven, the temperature of the oven makes the cathode sheet and the separator 53 reach a certain temperature through heat radiation.

[0089] Optionally, the number of transmission belts 5012b may be belts that are installed according to the size of the cathode sheet. In some optional embodiments, the number of transmission belts 5012b may be two or more, and two or more transmission belts 5012b are installed at intervals from each other and together carry the cathode sheet and separator 53, thereby ensuring the stability of the force applied to the cathode sheet and further ensuring that the cathode sheet moves synchronously and stably along with the separator 53.

[0090] In one alternative embodiment, the number of heating conveying assemblies 501 is two or more, and each pair of heating conveying assemblies 501 is installed opposite each other in a pair, and the two heating conveying assemblies 501 in the same pair clamp and convey the cathode sheet and separator 53 together using the transmission belts 5012b installed opposite each other.

[0091] By installing the heating conveying assemblies 501 in pairs and allowing the paired heating conveying assemblies 501 to clamp the cathode sheet and the separator 53 together, it is possible to ensure that the cathode sheets on the two separators 53 move synchronously with their corresponding separators 53, and further to better ensure the stability of the relative position between each cathode sheet and the separator 53, thereby ensuring the accuracy of the position of the cathode sheet on the separator 53 before the roller pressing member 502.

[0092] As one alternative embodiment, the roller pressing member 502 may include a pair of pressing rollers 5021, which may press the cathode sheet and separator 53 after heating by the pair of pressing rollers 5021, thereby further combining the two and forming an assembly that is laminated together with the anode sheet.

[0093] In one optional embodiment, a dust removal member 503 is provided on the roller pressing member 502 and / or the transmission belt 5012b, i.e., a dust removal member 503 is provided on at least one of the roller pressing member 502 and the transmission belt 5012b, and the dust removal member 503 also employs a combination of a brush and a dust suction device to remove dust from the stacked assembly and better ensure the performance of the stacked battery cells.

[0094] 29 to 31 , in some alternative embodiments, the stacked battery cell manufacturing system provided by the above embodiments includes a stacking mechanism 600 including a power source 601 and a rocking mechanism 602. The rocking mechanism 602 has a gap 6021 through which the assemblies to be stacked pass. The power source 601 is connected to the rocking mechanism 602 and drives the rocking mechanism 602 to rock back and forth along a predetermined trajectory, thereby stacking the assemblies to be stacked back and forth and forming the stacked battery cell. The stacking mechanism 600 employs the above structural format, which is simple in structure and low in cost, and can reciprocally fold the assemblies to be stacked based on the traces on the anode sheet, resulting in superior performance of the formed stacked battery cell.

[0095] In one alternative preferred embodiment, the rocking mechanism 602 includes a mounting base 6022 and a pair of clamping rollers 6023 connected to the mounting base 6022, with a gap 6021 formed between the pair of clamping rollers 6023, and the rocking mechanism 602 connected to the power source 601 via the mounting base 6022. The above structural form of the rocking mechanism 602 makes it easy to connect to the power source 601 and better satisfies the power transmission requirements, while also meeting the passage requirements of the stacked assembly, which can be folded back and forth according to a predetermined trace, and ensuring the packing requirements of the stacked battery cells.

[0096] Optionally, the power source 601 can employ a drive motor, the mounting base 6022 can include a pair of mounting plates spaced apart, and the clamping rollers 6023 are located between the two mounting plates, with their axial ends connected to the corresponding mounting plates, respectively.

[0097] In some alternative embodiments, the swinging mechanism 602 further includes limit reinforcing rollers 6024 installed as a pair, which are located upstream of the clamping rollers 6023 and connected to the mounting base 6022. By installing the limit reinforcing rollers 6024, the tilt angle of the stacked assemblies can be limited when the swinging mechanism 602 moves, which can better ensure that the stacked assemblies perform reciprocating folding according to the corresponding traces, and further ensure stacking accuracy.

[0098] In addition, the installation of the limit reinforcing roller 6024 further provides a reinforcing effect to the mounting base 6022, preventing changes in the relative position between the mounting base 6022 and the clamping roller 6023 or between clamping rollers 6023 installed in pairs when the swinging mechanism 602 swings along a predetermined trajectory, thereby better ensuring the stacking requirements of the stacked battery cells.

[0099] In some alternative embodiments, the manufacturing system for stacked battery cells provided by the above embodiments further includes a main conveying mechanism 700, which is located between the combining mechanism 500 and the stacking mechanism 600 and is used to provide driving power to the assemblies to be stacked, thereby better ensuring that the assemblies to be stacked move to the stacking mechanism 600 at a predetermined speed. The drive motor for supplying power to the anode sheets mentioned in the above embodiments may be the main conveying mechanism 700.

[0100] As a result, the stacked battery cell manufacturing system provided by the embodiments of the present application includes a first conveying mechanism 100, a separator conveying mechanism 200, a mark forming mechanism 300, a second conveying mechanism 400, a combining mechanism 500, and a stacking mechanism 600. The mark forming mechanism 300 is installed to form marks on the anode sheet, which eliminates the need to cut the anode sheet, prevents burrs from occurring, and ensures the safety of the stacked battery cell. At the same time, the structure of the stacked battery cell manufacturing system can be simplified.

[0101] In an embodiment, as shown in FIGS. 21 to 32 , the embodiment of the present application further provides a method for forming a stacked battery cell, including steps S100 of providing an anode sheet and forming a plurality of traces on the anode sheet at intervals in the extension direction W of the anode sheet; S200 of providing a separator 53 that is installed in pairs with the anode sheet with the traces and sandwiching the anode sheet between the paired separators 53; S300 of providing a plurality of cathode sheets on the separator 53 so that the plurality of cathode sheets are attached at intervals along the extension direction W and connected to the surface of the separator 53 away from the anode sheet to form a stacked assembly, with each cathode sheet positioned between two adjacent traces; and S400 of stacking the stacked assemblies along the positions of the plurality of traces back and forth to form a stacked battery cell.

[0102] In some alternative examples, the method for forming a stacked battery cell provided by the embodiments of the present application can be implemented by employing the stacked battery cell manufacturing system mentioned in each of the above embodiments.

[0103] In step S100, the provided anode sheet has a continuous belt-like structure, and the trace is a structure formed at the removed portion of the material on the anode sheet after a material removing member is used to remove some material from the anode sheet, where the material removing member is one of a metal cutter, a laser cutter, and a liquid etching tool. That is, the material removing member may be the trace forming mechanism 300 mentioned in each of the above embodiments.

[0104] In some alternative examples, the material removed from the anode sheet by the material removing member may be the electrode active material, and in this case, the depth of the mark is equal to or less than the thickness of the electrode active material layer 51 b. The material removed from the anode sheet by the material removing member may be the electrode active material and the material of the current collector 51 a, and in this case, the depth of the mark is greater than the thickness of the electrode active material layer 51 b.

[0105] In some alternative examples, in step S100, of two adjacent marks, one mark is located on one surface of the anode sheet in the thickness direction H of the anode sheet itself, and the other mark is located on the other surface of the anode sheet in the thickness direction H of the anode sheet.

[0106] When the forming method of the present application is performed using the stacked battery cell manufacturing system provided by any of the above embodiments, in step S100, the first conveying mechanism 100 can provide an anode sheet, and the mark forming mechanism 300 can place a corresponding mark on the anode sheet. In step S200, the separator conveying mechanism 200 can provide a separator 53 arranged as a pair.

[0107] In some alternative embodiments, in step S300, one of two adjacent cathode sheets is connected to one of the paired separators 53, and the other is connected to the other of the paired separators 53. This arrangement allows the formed stacked battery cell to better meet usage requirements and optimize the electrical properties of the stacked battery cell.

[0108] In some alternative examples, the cathode sheet can be provided by the second conveying mechanism 400 in the stacked battery cell manufacturing system provided by any of the above embodiments.

[0109] In step S400, the stacking mechanism 600 in the stacked battery cell manufacturing system provided by any of the above embodiments can stack the stacked assemblies to complete the manufacturing requirements for the stacked battery cells.

[0110] The stacked battery cell molding method provided by the embodiments of the present application can meet the manufacturing needs of stacked battery cells and at the same time reduce the safety risks of stacked battery cells.

[0111] In the battery cell stack manufacturing system and battery cell stack forming method provided in the above-described embodiments of the present application, the thickness of the anode sheet in the thickness direction H, where the anode sheet has a mark, is smaller than the thickness of other areas of the anode sheet where the mark is not formed. The design of the mark ensures that the anode sheet is easier to fold in the area where the mark is present than in other areas.

[0112] Optionally, the traces may be grooves 5111a according to the above embodiments formed after removing material from the anode sheet. Optionally, the shape of the grooves 5111a may be a U-shaped groove, a triangular groove, or another regular polygonal groove, or an irregularly shaped groove. Optionally, the traces penetrate the anode sheet in the belt width direction of the anode sheet. The belt width direction of the anode sheet is the same as the first direction X, and is perpendicular to both the extension direction W and the thickness direction H of the anode sheet.

[0113] Optionally, the number of grooves 5111a is two or more, two or more grooves 5111a are spaced apart along the first direction X, or the number of grooves 5111a is one.

[0114] Optionally, the traces may be through-holes 5111b according to the above embodiments formed after removing material from the anode sheet. When the first electrode sheet 51 is in an unfolded state, the through-holes 5111b penetrate the two electrode active material layers 51b and the current collector 51a along the thickness direction H of the first electrode sheet 51. In one example, the shape of the through-holes 5111b may be rectangular, square, elliptical, trapezoidal, or triangular. The number of through-holes 5111b is two or more, and the two or more through-holes 5111b are spaced apart along the first direction X. In one embodiment, the number of through-holes 5111b is one.

[0115] Optionally, the traces may be the grooves 5111a and through-holes 5111b according to the above embodiments formed after removing material from the anode sheet. Optionally, the number of through-holes 5111b may be two or more, and one or more grooves 5111a may be provided between two adjacent through-holes 5111b along the first direction X. Alternatively, the number of grooves 5111a may be two or more, and one or more through-holes 5111b may be provided between two adjacent grooves 5111a.

[0116] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and equivalents may be substituted for components therein without departing from the scope of the present application, and in particular, the respective technical features mentioned in each embodiment may be combined in any manner unless there is a structural conflict. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An electrode assembly for use in a secondary battery, a first electrode sheet and a second electrode sheet having an opposite polarity to the first electrode sheet; the first electrode sheet includes a plurality of folding portions and a plurality of first laminated portions provided in a stacked manner, each folding portion being used to connect two adjacent first laminated portions, and the folding portion has a guide portion that guides the folding portion so that it is folded during manufacturing; the second electrode sheet includes a plurality of second laminated portions, each of the second laminated portions being provided between two adjacent first laminated portions; The guide portion includes at least one groove, the first electrode sheet has a current collector and an electrode active material layer applied to the current collector; The groove is formed by removing a portion of the electrode active material layer and the current collector along the thickness direction of the first electrode sheet.

2. The electrode assembly of claim 1 , wherein the guide portion is disposed along a first direction, and the first direction is perpendicular to a bending direction of the bending portion.

3. 3. The electrode assembly according to claim 1, wherein each of the first laminated portions has two opposing first outer edges, and after the folding portion is guided to be folded during manufacturing, the first outer edges of two adjacent first laminated portions connected to the folding portion are aligned.

4. The electrode assembly according to claim 2 , wherein the dimension of the guide portion in the first direction is set according to the dimension of the bent portion in the first direction.

5. The electrode assembly of claim 1 , wherein when the guide portion includes a plurality of grooves and / or a plurality of through holes, the plurality of grooves and / or the plurality of through holes are disposed at intervals.

6. The electrode assembly according to claim 2 , wherein a projection of the guide portion onto a plane perpendicular to the first direction has a shape selected from the group consisting of a triangle, a trapezoid, a U-shape, a rectangle, and a V-shape.

7. An electrode assembly for use in a secondary battery, a first electrode sheet and a second electrode sheet having an opposite polarity to the first electrode sheet; the first electrode sheet includes a plurality of folding portions and a plurality of first laminated portions provided in a stacked manner, each folding portion being used to connect two adjacent first laminated portions, and the folding portion has a guide portion that guides the folding portion so that it is folded during manufacturing; the second electrode sheet includes a plurality of second laminated portions, each of the second laminated portions being provided between two adjacent first laminated portions; The electrode assembly, wherein the guide portions are both located on the same surface of the first electrode sheet.

8. A secondary battery comprising the electrode assembly according to any one of claims 1 to 7.

9. A battery module comprising the secondary battery according to claim 8 .

10. 10. A device including the secondary battery of claim 8 for supplying electrical energy.

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