Winding device and winding method

Abstract

The present application relates to a winding device and a winding method, and belongs to the field of battery manufacturing technology. The present application proposes a winding device, comprising: a winding component; a traction mechanism, the traction mechanism being configured to pull the passing-out section of the isolation membrane after the isolation membrane passes through the winding component, so that the length of the passing-out section reaches a preset value; wherein the winding component is configured to start winding after the length of the passing-out section reaches a preset value to form an electrode assembly. The present application also proposes a winding method for winding an electrode assembly. The winding device and the winding method are used for winding an electrode assembly with higher safety performance, which can realize the industrialized production of the electrode assembly and improve the manufacturing efficiency of the electrode assembly.

Description

Technical Field

[0001] The present application relates to the field of battery manufacturing technology, and more specifically, to a winding device and a winding method. Background Art

[0002] With the rapid development of the new energy vehicle industry, power battery technology is becoming increasingly mature, and the safety performance of power batteries has become a key indicator of their performance. The wound electrode assembly is a critical component within the battery cell, and its safety plays a decisive role in the safety of the battery cell. However, even if improvements are made to the electrode assembly structure to improve the safety of the battery cell, the corresponding winding equipment currently does not exist, making industrial production impossible even with these structural improvements. Summary of the Invention

[0003] To this end, the present application proposes a winding device and a winding method for winding and forming an electrode assembly with higher safety performance, which can realize the industrial production of the electrode assembly and improve the manufacturing efficiency of the electrode assembly.

[0004] Some embodiments of the present application provide a winding device for winding and forming an electrode assembly, the winding device comprising: a winding component; a traction mechanism, the traction mechanism being configured to pull the passing-out section of the isolation film after the isolation film passes through the winding component so that the length of the passing-out section reaches a preset value; wherein the winding component is configured to start winding after the length of the passing-out section reaches the preset value to form the electrode assembly.

[0005] The winding device of the embodiment of the present application includes a traction mechanism, which can pull the exit section of the isolation membrane to move so that the length of the exit section reaches a preset value. The exit section of the isolation membrane is also wound into the winding component, so that the exit section of the isolation membrane is stacked with the isolation membrane newly entering the winding component so that the isolation membrane between the negative electrode sheet and the positive electrode sheet of the inner circle has a multi-layer isolation membrane. When lithium precipitation occurs, lithium dendrites are not easy to pierce the isolation membrane, causing the negative electrode sheet and the positive electrode sheet to contact and thus cause an internal short circuit in the electrode assembly. The electrode assembly wound and formed using the winding device has high safety performance, and the winding device can realize the industrial production of such electrode assemblies, improving the manufacturing efficiency of such electrode assemblies.

[0006] According to some embodiments of the present application, the traction mechanism includes a traction member and a driving member, the driving member is used to drive the traction member to move between a first position and a second position, and the traction member is configured to pull the passing-out section during the process of moving from the first position to the second position.

[0007] In the above solution, under the drive of the driving member, the traction member pulls the pass-through section of the isolation membrane during the process of moving from the first position to the second position, thereby automatically pulling the pass-through section of the isolation membrane to reach a preset value.

[0008] According to some embodiments of the present application, the traction member is configured to return from the second position to the first position after the winding component starts winding, and provide tension to the isolation film during the process of returning to the first position.

[0009] In the above scheme, after the winding component starts winding, the traction member tensions the isolation membrane in the process of returning from the second position to the first position, so that the protruding section of the isolation membrane is tightly wound around the winding component without wrinkles, thereby improving the winding quality of the isolation membrane and making the electrode assembly have better safety performance.

[0010] According to some embodiments of the present application, the traction member is configured to return from the second position to the first position after the winding component starts winding, and release the isolation film when returning to the first position.

[0011] In the above solution, the pulling member releases the separator when returning from the second position to the first position, and the winding member continues to wind to roll the remaining portion of the passed-out section of the separator into the winding member to form the electrode assembly.

[0012] According to some embodiments of the present application, when the traction member is in the first position, the traction member is located below the winding member along the direction of gravity.

[0013] In the above scheme, when the traction member is in the first position, it is located below the winding member. After the traction member returns to the first position and releases the isolation membrane, the remaining part of the protruding section of the isolation membrane naturally droops along the direction of gravity. The remaining part of the protruding section of the isolation membrane is flat and wrinkle-free during the process of entering the winding member, which improves the winding quality of the isolation membrane and makes the electrode assembly have better safety performance.

[0014] According to some embodiments of the present application, the moving direction of the traction member intersects with the direction of gravity.

[0015] In the above scheme, the traction member moves along a direction intersecting with the direction of gravity, so that the path of the traction member moving between the first position and the second position intersects with the direction of gravity, reducing the space occupied by the traction member in the direction of gravity during movement and having a longer travel range.

[0016] According to some embodiments of the present application, the traction member includes a pair of first clamping portions, and the pair of first clamping portions are used to clamp the ends of the isolation membrane.

[0017] In the above solution, a pair of clamping parts are used to clamp the end of the isolation membrane, which can reliably pull the pass-through section of the isolation membrane to move, thereby reliably pulling out the pass-through section of the isolation membrane to a preset length.

[0018] According to some embodiments of the present application, the winding device further includes: a fixing member for fixing the end of the isolation membrane, the fixing member being configured to release the end of the isolation membrane when the traction member returns to the first position; wherein the traction member is configured to push the portion of the isolation membrane located between the fixing member and the winding member.

[0019] In the above embodiment, the fixing member secures the end of the separator, while the pulling member pushes against the portion of the separator located between the fixing member and the winding member, pulling the extended portion of the separator to a predetermined length. This shortens the travel length of the pulling member when it moves between the first and second positions, reducing the space occupied by the pulling member during movement. When the pulling member returns to the first position, the fixing member releases the end of the separator, and the winding member continues winding to incorporate the remaining portion of the extended portion of the separator into the winding member, thereby forming the electrode assembly.

[0020] According to some embodiments of the present application, the fixing member includes a pair of second clamping portions, and the pair of second clamping portions are used to clamp the ends of the isolation membrane.

[0021] In the above solution, a pair of second clamping parts are used to clamp the end of the isolation membrane, which can reliably fix the end of the isolation membrane, and the traction member can reliably pull out the protruding section of the isolation membrane to a preset length.

[0022] According to some embodiments of the present application, the traction member is a movable pulley.

[0023] In the above solution, the traction member is set as a movable pulley. During the process of pushing the isolation membrane, the traction member can automatically adjust the contact angle of the traction member relative to the surface of the isolation membrane by rotating around its axis to avoid scratching the isolation membrane.

[0024] According to some embodiments of the present application, the winding device further includes: a fixed pulley, disposed between the winding component and the traction component, for guiding the movement of the isolation membrane.

[0025] In the above scheme, by arranging a fixed pulley between the winding component and the traction component, the running direction of the isolation membrane can be guided and changed, reducing the impact of the rotation process of the winding component on the outlet section, which is beneficial to controlling the running direction of the outlet section from the fixed pulley to the end of the isolation membrane. It is not only beneficial to calculate the length of the outlet section, but also can improve the working reliability of the winding equipment.

[0026] Some embodiments of the present application further provide a winding method for winding an electrode assembly, the winding method comprising:

[0027] Passing the isolation film through the winding component, wherein the portion of the isolation film that passes through the winding component is the passing-out section;

[0028] pulling the outgoing section of the isolation membrane so that the length of the outgoing section reaches a preset value;

[0029] The winding member begins to be wound to form the electrode assembly.

[0030] By using the winding method of the embodiment of the present application to wind and form an electrode assembly, the protruding section of the isolation membrane with a preset length can also be wound into the winding component, so that the protruding section of the isolation membrane and the isolation membrane newly entering the winding component are stacked so that the isolation membrane between the negative electrode plate and the positive electrode plate of the inner circle has a multi-layer isolation membrane. When lithium deposition occurs, lithium dendrites are not easy to pierce the isolation membrane, causing the negative electrode plate and the positive electrode plate to contact and thus cause an internal short circuit in the electrode assembly. The electrode assembly wound and formed using this winding method has higher safety performance.

[0031] According to some embodiments of the present application, the preset value is greater than the circumference of the winding component.

[0032] In the above scheme, the preset value of the protruding section is greater than the circumference of the winding component, and a multi-layer isolation membrane can be set at least between the first bending area of the innermost circle of the positive electrode sheet and the negative electrode sheet inside it, thereby preventing lithium crystallization from piercing the isolation membrane when lithium deposition occurs inside the first bending area of the innermost circle of the positive electrode sheet, which can significantly improve the safety performance of the electrode assembly.

[0033] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0035] Figure 1 Shown is a schematic structural diagram of a winding device according to some embodiments of the present application;

[0036] Figure 2 Shown is a cross-sectional view of an electrode assembly wound by a winding device according to some embodiments of the present application;

[0037] Figure 3The figure shows a schematic diagram of a traction member of a traction mechanism in a winding device in some embodiments of the present application in a first position;

[0038] Figure 4 The figure shows a schematic diagram of a traction member of a traction mechanism in a winding device in some embodiments of the present application in a second position;

[0039] Figure 5 The figure shows a state diagram of a winding component in a winding device in some embodiments of the present application winding to drive a traction member to move toward a first position;

[0040] Figure 6 The figure shows a state diagram of a traction member of a traction mechanism in a winding device in some embodiments of the present application, after returning to the first position and releasing the isolation film;

[0041] Figure 7 The figure shows a schematic structural diagram of another traction member of the traction mechanism in the winding device in some embodiments of the present application;

[0042] Figure 8 Shown is Figure 3 A schematic structural diagram of a winding device further provided with a fixed pulley (the driving member is not shown);

[0043] Figure 9 Shown is Figure 7 A schematic structural diagram of a winding device further provided with a fixed pulley;

[0044] Figure 10 Shown is a process flow chart of the winding method of some embodiments of the present application;

[0045] Figure 11 Shown is Figure 3 Schematic diagram of the winding process of the winding equipment;

[0046] Figure 12 Shown is Figure 7 Schematic diagram of the winding process of the winding equipment;

[0047] The above drawings are not provided to scale.

[0048] Icons: 100-winding equipment; 110-winding component; 111-winding needle; 112-gap; 1121-first end; 1122-second end; 113-isolating film clamping part; 114-incoming side; 115-pulling side; 120-traction mechanism; 121-traction member; 1211-first clamping part; 122-driving member; 130-fixing member; 131-second clamping part; 140-fixed pulley; 200-electrode assembly; 210-negative electrode sheet; 220-positive electrode sheet; 230-isolating film; 231-passing-through section; 2311-starting end; 232-end; 233-first isolating film; 234-second isolating film; 235-bending area. DETAILED DESCRIPTION

[0049] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0050] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0051] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0052] It should be noted that, unless otherwise specified or limited, the terms "mounted," "connected," "connected," and "attached" are to be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediary, or internal connections between two components. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0053] The term "plurality" used in this application refers to two or more (including two).

[0054] The electrode assembly mentioned in the embodiments of the present application is an important component of a battery cell in a lithium-ion battery. The electrode assembly is formed by stacking and winding a positive electrode sheet, a negative electrode sheet and a separator. The separator is arranged between the positive electrode sheet and the negative electrode sheet to insulate and isolate the positive electrode sheet from the negative electrode sheet. The battery cell mainly relies on the movement of metal ions between the positive electrode sheet and the negative electrode sheet to work. The positive electrode sheet includes a positive electrode collector and a positive electrode active material layer, and the positive electrode active material layer is coated on the surface of the positive electrode collector. The negative electrode sheet includes a negative electrode collector and a negative electrode active material layer, and the negative electrode active material layer is coated on the surface of the negative electrode collector.

[0055] In the related art, after the electrode assembly is wound and formed, the positive electrode sheet and the negative electrode sheet in the bending area of the innermost turns of the electrode assembly have an area difference within the same angle range, which easily causes lithium deposition. The lithium crystallization easily pierces the isolation membrane, causing the positive electrode sheet and the negative electrode sheet to short-circuit, resulting in a short circuit inside the electrode assembly. At present, there is an idea for improving the electrode assembly, which is to set several layers of isolation membrane between the positive electrode sheet and the negative electrode sheet in the innermost turns of the electrode assembly. Even if lithium deposition occurs, lithium crystallization is not easy to pierce the isolation membrane, thereby overcoming the above defects and making the electrode assembly have better safety performance when lithium deposition occurs in the innermost turns. However, there is currently no corresponding winding equipment and winding method that can realize the industrial production of such electrode assemblies.

[0056] The inventors discovered that in most electrode assembly winding processes, a pair of winding needles are typically used to first grip the separator and wind several turns, followed by the sequential addition of the negative and positive electrode sheets. If the separator's end could be passed through the winding unit to form an exit section, and the exit section were also wound around the winding unit, the exit section could be simultaneously wound in as the winding unit rotates one revolution, pulling in a new separator from the incoming side. This would allow for industrialized production of these electrode assemblies without requiring a new separator feeding mechanism, reducing the need for and cost of improvements to existing winding equipment.

[0057] Based on the above ideas, the inventor of this application proposed a technical solution, which further sets a traction mechanism on the pulling-out side of the winding component, first uses the traction mechanism to pull the passing section of the isolation membrane to a preset value, and then uses the winding component to start winding to form the above-mentioned electrode assembly with higher safety performance. This not only can realize the industrial production of the electrode assembly, but also can improve the manufacturing efficiency of the electrode assembly.

[0058] Figure 1 Shown is a schematic structural diagram of a winding device according to some embodiments of the present application; Figure 2 Shown is a cross-sectional view of an electrode assembly wound by a winding device according to some embodiments of the present application.

[0059] like Figure 1 and Figure 2 As shown, some embodiments of the present application provide a winding device 100 for winding an electrode assembly 200 . The winding device 100 includes a winding component 110 and four feeding mechanisms (not shown in the figure).

[0060] The battery cells applicable to the electrode assembly 200 described in the embodiments of this application may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries, etc., and the embodiments of this application are not limited to this. However, for the sake of simplicity, the following embodiments are described using the winding process of the electrode assembly in a lithium-ion battery as an example.

[0061] like Figure 1 and Figure 2 As shown, the electrode assembly 200 includes a negative electrode sheet 210, a positive electrode sheet 220, a first separator 233, and a second separator 234, which are stacked and wound. The first separator 233 and the second separator 234 are wound before the negative electrode sheet 210 and the positive electrode sheet 220. In the stacked first separator 233 and the second separator 234 wound by the winding member 110 during one winding, the second separator 234 is located on the inner side of the first separator 233 (i.e., on the side closer to the winding axis). After being wound at least one turn around the first and second separators 233 and 234, the negative electrode sheet 210 enters between the first and second separators 233 and 234 to be wound into the winding member 110. After the negative electrode sheet 210 is wound around once, the positive electrode sheet 220 enters the side of the second separator 234 away from the negative electrode sheet 210 to be wound into the winding member 110.

[0062] It is understood that a "turn" in this application refers to a point in the electrode assembly 200 as the starting point, a circle along the winding direction to another point, and a line connecting the other point and the starting point extends along the radial direction of the electrode assembly. A "half turn" in this application refers to half of a turn. Those skilled in the art will understand the meaning of other numbers of turns, which will not be further explained here.

[0063] like Figure 1 As shown, the winding component 110 is used to wind the electrode assembly 200, and four feeding mechanisms (not shown in the figure) are arranged on the incoming side 114 of the winding component 110. The four feeding mechanisms are used to provide the negative electrode sheet 210, the positive electrode sheet 220, the first isolation film 233 and the second isolation film 234 to the winding component 110 respectively.

[0064] like Figure 1 As shown, the winding member 110 includes a pair of winding pins 111, each of which is semi-cylindrical or semi-elliptical. The pair of winding pins 111 are assembled together to form the cylindrical or elliptical outer surface of the winding member 110. The pair of winding pins 111 rotate together to wind the negative electrode sheet 210, the positive electrode sheet 220, the first separator 233, and the second separator 234 around the outer surface of the winding member 110. For simplicity of description, the first separator 233 and the second separator 234 are collectively referred to as the separator 230.

[0065] A gap 112 is defined between the pair of winding needles 111, through which the separator 230 passes. A pair of separator clamping portions 113 are provided on one side of the winding needles 111, forming the gap 112. After the separator 230 passes through the gap 112, the pair of separator clamping portions jointly clamp the separator 230, and the winding unit 110 begins winding to form the electrode assembly 200. The winding unit 110 rotates in a first direction P.

[0066] like Figure 1 As shown, some embodiments of the present application provide a winding apparatus 100 for winding an electrode assembly 200. The winding apparatus 100 includes a winding unit 110 and a pulling mechanism 120. The pulling mechanism 120 is configured to pull a passing section 231 of the separator 230 after the separator 230 passes through the winding unit 110, so that the length of the passing section 231 reaches a preset value. The winding unit 110 is configured to begin winding after the length of the passing section 231 reaches the preset value, thereby forming the electrode assembly 200.

[0067] One end of the gap 112 corresponding to the incoming side 114 of the winding component 110 is the first end 1121, and the other end is the second end 1122. The isolation film 230 enters the gap 112 from the first end 1121 and passes through the gap 112 from the second end 1122. It can be understood that during the rotation of the winding component 110, the directions of the first end 1121 and the second end 1122 of the gap 112 are also constantly changing. Figure 1As shown, in some embodiments of the present application, the gap 112 is linear, and the first end 1121 and the second end 1122 are respectively located on opposite sides of the radial direction of the winding component 110; in other embodiments, the gap 112 can also be a broken line, and the first end 1121 and the second end 1122 form an angle of 90°, 150°, etc. around the circumference of the winding component 110.

[0068] The exit section 231 of the isolation membrane 230 refers to the portion of the isolation membrane 230 that exits the winding component 110, that is, the portion between the end 232 of the isolation membrane 230 and the second end 1122 of the gap 112. The position where the isolation membrane 230 exits the second end 1122 of the gap 112 is the starting end 2311 of the exit section 231, and the end 232 of the isolation membrane 230 is the tail end of the exit section 231. The traction mechanism 120 can pull the isolation membrane 230 to move by acting on the tail end of the exit section 231 (that is, the end 232 of the isolation membrane 230), or by acting on the middle portion of the exit section 231 (that is, the portion between the starting end 2311 and the tail end of the exit section 231). The traction mechanism 120 can automatically pull the exit section 231 to move, or it can pull the exit section 231 to move by manual drive.

[0069] The winding component 110 further includes a pulling-out side 115 corresponding to the incoming side 114. The pulling mechanism 120 is disposed on the pulling-out side 115 of the winding component 110 and is used to pull the passing section 231 of the isolation film 230 to move so as to pull the isolation film 230 out of the second end 1122 of the gap 112. Figure 1 As shown, in some embodiments of the present application, the incoming side 114 and the pulling side 115 of the winding component 110 can be respectively located on opposite sides of the radial direction to reasonably arrange the incoming mechanism and the traction mechanism 120; in other embodiments, the incoming side 114 and the pulling side 115 of the winding component 110 can also be respectively arranged at a certain angle around the circumference of the winding component 110.

[0070] The winding device 100 of the embodiment of the present application includes a traction mechanism 120, which can pull the outlet section 231 of the separator 230 to move so that the length of the outlet section 231 reaches a preset value. The outlet section 231 of the separator 230 is also wound into the winding part 110, so that the outlet section 231 of the separator 230 is stacked with the separator 230 newly entering the winding part 110, so that the separator 230 between the inner circle of the negative electrode sheet 210 and the positive electrode sheet 220 has multiple layers of separators. When lithium deposition occurs, lithium dendrites are not easy to pierce the separator, causing the negative electrode sheet 210 and the positive electrode sheet 220 to contact and thus cause an internal short circuit in the electrode assembly 200. The electrode assembly 200 wound and formed using the winding device 100 has high safety performance, and the winding device 100 can realize the industrial production of such electrode assemblies 200, thereby improving the manufacturing efficiency of such electrode assemblies 200.

[0071] Figure 3 The figure shows a schematic diagram of a traction member of a traction mechanism in a winding device in some embodiments of the present application in a first position; Figure 4 Shown is a schematic diagram of a traction member of a traction mechanism in a winding device in some embodiments of the present application being in a second position.

[0072] like Figure 3 and Figure 4 As shown, in some embodiments of the present application, the traction mechanism 120 includes a traction member 121 and a driving member 122, the driving member 122 is used to drive the traction member 121 to move between a first position and a second position, and the traction member 121 is configured to pull the outlet section 231 during the process of moving from the first position to the second position.

[0073] The moving path of the traction member 121 between the first position and the second position can be a straight line or a curve; Figure 4 As shown, in some embodiments of the present application, the pulling member 121 moves from the first position to the second position along the first sub-direction Q1 of the second direction, and the moving path of the pulling member 121 is a straight line.

[0074] The traction member 121 can act on the passing section 231 of the isolation membrane 230 by clamping, or by vacuum adsorption, or by pushing the middle of the isolation membrane 230 to pull out the passing section 231 of the isolation membrane 230.

[0075] The first position is the position where the traction member 121 starts to act on the outlet section 231 of the isolation membrane 230, and the second position is the position where the traction member 121 pulls the outlet section 231 of the isolation membrane 230 to move so that the length of the outlet section 231 is a preset value. The traction member 121 moves from the first position to the second position, pulling the isolation membrane 230 outward from the second end 1122 of the gap 112, so that the length of the outlet section 231 continues to increase until the length of the outlet section 231 reaches the preset value.

[0076] The first position corresponds to the position of the second end 1122 of the gap 112 of the winding member 110 before the winding begins, so that the traction member 121 acts on the isolation film 230 at the first position. The second position can be located to one side of the first position in the horizontal direction, below the first position in the direction of gravity G, or to one side of the first position in other directions.

[0077] The traction member 121 is mounted on the actuator end of the driver 122, which drives the traction member 121 between a first position and a second position. Based on the aforementioned embodiment in which the movement path of the traction member 121 is linear, the driver 122 can be a common linear drive mechanism such as a linear cylinder or an electric push rod. Based on the aforementioned embodiment in which the movement path of the traction member 121 is curved, the driver 122 can also be a rotary drive mechanism such as a powered turntable to drive the traction member 121 to move circumferentially around the driver 122.

[0078] The traction mechanism 120 may further include a guide rail assembly, and the traction member 121 is slidably mounted on the guide rail assembly, and the traction member 121 is guided by the guide rail assembly to move between the first position and the second position.

[0079] In the above solution, driven by the driving member 122, the traction member 121 pulls the outlet section 231 of the isolation membrane 230 during the movement from the first position to the second position, thereby automatically pulling the outlet section 231 of the isolation membrane 230 to reach a preset value.

[0080] Figure 5 Shown is a schematic diagram of a state in which a winding component in a winding device in some embodiments of the present application is wound to drive a traction member to move toward a first position.

[0081] like Figure 5 As shown, in some embodiments of the present application, the traction member 121 is configured to return from the second position to the first position after the winding component 110 starts winding, and provide tension to the isolation film 230 during the process of returning to the first position.

[0082] The path that the pulling member 121 moves from the first position to the second position and the path that the pulling member 121 moves from the second position to the first position may be the same or different. In some embodiments of the present application, the pulling member 121 returns from the second position to the first position along the original path that it moved from the first position to the second position, that is, moves from the second position to the first position along the second sub-direction Q2 of the second direction.

[0083] After the pulling member 121 pulls the exit section 231 of the isolation film 230 to the second position, the winding member 110 rotates about the first direction P, winding the exit section 231 around the winding member 110, and the length of the exit section 231 decreases until it is completely wound into the winding member 110. During the process of the pulling member 121 moving from the second position to the first position along the second sub-direction Q2 of the second direction, the pulling member 121 continuously acts on the portion of the exit section 231 not wound into the winding member 110, thereby tensioning the portion of the exit section 231 not wound into the winding member 110.

[0084] There are various implementations for achieving the tensioning force provided by the traction member 121 to the isolation diaphragm 230. The tensioning force can be provided by the driver 122 itself, or by other elastic members. For example, in an embodiment where the driver 122 is a linear cylinder, the linear cylinder can be set to a force-releasing state, with damping generated by the internal air pressure of the linear cylinder. For another example, the traction mechanism 120 can further include a spring, one end of which is fixed and the other end abuts the traction member 121. As the traction member 121 moves from the second position to the first position, the other end of the spring applies a force to the traction member 121 toward the second position.

[0085] In the above scheme, after the winding component 110 starts winding, the traction member 121 tensions the isolation membrane 230 in the process of returning from the second position to the first position, so that the passing section 231 of the isolation membrane 230 is tightly wound around the winding component 110 without wrinkles, thereby improving the winding quality of the isolation membrane 230 and making the electrode assembly 200 have better safety performance.

[0086] Figure 6 The diagram shows a state in which the traction member of the traction mechanism of the winding device in some embodiments of the present application returns to the first position and releases the isolation film.

[0087] like Figure 6 As shown, in some embodiments of the present application, the pulling member 121 is configured to return from the second position to the first position after the winding component 110 starts to wind, and release the isolation film 230 when returning to the first position.

[0088] When the pulling member 121 returns to the first position, the pulling member 121 releases the isolation film 230 to allow the winding component 110 to continue to be wound into the remaining portion of the passing-out section 231 .

[0089] The first position may be located below the gravity direction G of the winding member 110 , or may be located at other positions of the winding member 110 , such as obliquely below or on one side in the horizontal direction.

[0090] In the above solution, the pulling member 121 releases the separator 230 when returning from the second position to the first position, and the winding member 110 continues to wind to roll the remaining portion of the protruding section 231 of the separator 230 into the winding member 110 to form the electrode assembly 200 .

[0091] like Figure 6 As shown, in some embodiments of the present application, when the traction member 121 is in the first position, along the gravity direction G, the traction member 121 is located below the winding component 110.

[0092] When the pulling member 121 is in the first position, the pulling member 121 may be located directly below the winding member 110 along the direction G of gravity, or may be located obliquely below the winding member 110 along the direction G of gravity.

[0093] In the above scheme, when the traction member 121 is in the first position, it is located below the winding member 110. After the traction member 121 returns to the first position and releases the isolation film 230, the remaining part of the passing section 231 of the isolation film 230 naturally droops along the gravity direction G. The remaining part of the passing section 231 of the isolation film 230 is flat and wrinkle-free during the process of entering the winding member 110, which improves the winding quality of the isolation film 230 and makes the electrode assembly 200 have better safety performance.

[0094] like Figure 5 and Figure 6 As shown, in some embodiments of the present application, the moving direction of the traction member 121 intersects with the gravity direction G.

[0095] During the movement of the traction member 121 between the first position and the second position, its movement path can be multiple directions that intersect the direction of gravity G. In some embodiments of the present application, based on the aforementioned embodiment in which the traction member 121 is located directly below the winding member 110 along the direction of gravity G when in the first position, the second direction is a horizontal direction, the traction member 121 moves in the horizontal direction, and the movement direction of the traction member 121 and the direction of the traction member 121 in the first position relative to the winding member 110 are arranged perpendicular to each other, so as to minimize the space occupied by the traction member 121 in the direction of gravity G during movement. In other embodiments, the movement direction of the traction member 121 and the direction of the traction member 121 in the first position relative to the winding member 110 can also be flexibly arranged.

[0096] In the above scheme, the traction member 121 moves along a direction intersecting with the gravity direction G, so that the path of the traction member 121 moving between the first position and the second position intersects with the gravity direction G, reducing the space occupied by the traction member 121 in the gravity direction G during the movement, and can have a longer travel range.

[0097] like Figure 6 As shown, in some embodiments of the present application, the traction member 121 includes a pair of first clamping portions 1211 , and the pair of first clamping portions 1211 are used to clamp the end portion 232 of the isolation membrane 230 .

[0098] The pair of first clamping parts 1211 clamp the isolation film 230 from both sides in the thickness direction of the isolation film 230 . The pair of first clamping parts 1211 may be a pair of pneumatic fingers or electric fingers.

[0099] The pair of first clamping parts 1211 pulls out the passage section 231 from the gap 112 of the winding component 110 by clamping the end 232 of the isolation film 230. The movement stroke of the pair of first clamping parts 1211 is equal to the pulled-out length of the passage section 231 based on the first position.

[0100] In the above solution, a pair of clamping parts is used to clamp the end portion 232 of the isolation membrane 230, which can reliably pull the passing section 231 of the isolation membrane 230 to move, thereby reliably pulling out the passing section 231 of the isolation membrane 230 to a preset length.

[0101] Figure 7 Shown is a schematic structural diagram of another traction member in the traction mechanism of the winding device in some embodiments of the present application.

[0102] like Figure 7 As shown, in some embodiments of the present application, the winding device 100 also includes a fixing member 130 for fixing the end 232 of the isolation membrane 230, and the fixing member 130 is configured to release the end 232 of the isolation membrane 230 when the traction member 121 returns to the first position; wherein, the traction member 121 is configured to push the portion of the isolation membrane 230 located between the fixing member 130 and the winding member 110.

[0103] The fixing member 130 can be disposed below the winding member 110 along the direction of gravity G. The fixing member 130 can also be disposed at other locations on the winding member 110. The fixing member 130 can fix the end 232 of the isolation film 230 by clamping or by adsorption.

[0104] The traction member 121 can be a long push rod extending along the width direction of the isolation membrane 230, which acts on the isolation membrane 230 through its outer peripheral surface; the traction member 121 can also be a roller or pulley that rotates around its own axis along the width direction of the isolation membrane 230.

[0105] The traction member 121 is arranged between the fixing member 130 and the winding member 110, and is used to push the middle part of the passing section 231 of the isolation membrane 230 (i.e., the part between the passing section 231 and the second end 1122 of the gap 112 to the end 232 of the isolation membrane 230).

[0106] The traction member 121 can be directly set at the midpoint between the winding member 110 and the fixing member 130. In the process of pushing the isolation film 230, the distance from the point of action of the isolation film 230 to the winding member 110 and the fixing member 130 is the same, and the length of the pass-through section 231 is greater than the moving stroke of the traction member 121. Preferably, when the fixing member 130 and the winding member 110 are arranged adjacent to each other, the length of the pass-through section 231 is approximately twice the moving stroke of the traction member 121, which can significantly shorten the moving stroke of the traction member 121 and reduce the space required. In other embodiments, the traction member 121 can also be located at other positions between the winding member 110 and the fixing member 130, such as at a position one-third between the winding member 110 and the fixing member 130.

[0107] Furthermore, another intermediate component (e.g., the fixed pulley 140 described below) may be provided between the traction member 121 and the winding member 110 to guide the movement of the isolation membrane 230. For example, the traction member 121 is provided at the midpoint between the intermediate component and the fixed component 130. During the process of pushing the isolation membrane 230, the distance from the point of application of the isolation membrane 230 to the intermediate component and the fixed component 130 is the same, and the length of the protruding section 231 from the intermediate component to the tail end is greater than the travel distance of the traction member 121.

[0108] In the above embodiment, the fixing member 130 fixes the end 232 of the separator 230, and the pulling member 121 pushes the portion of the separator 230 located between the fixing member 130 and the winding member 110, pulling the extended section 231 of the separator 230 to a predetermined length. This shortens the travel length of the pulling member 121 when it moves between the first position and the second position, thereby reducing the space occupied by the pulling member 121 during movement. When the pulling member 121 returns to the first position, the fixing member 130 releases the end 232 of the separator 230, and the winding member 110 continues winding to wind the remaining portion of the extended section 231 of the separator 230 into the winding member 110, thereby forming the electrode assembly 200.

[0109] like Figure 7As shown, in some embodiments of the present application, the fixing member 130 includes a pair of second clamping portions 131 , and the pair of second clamping portions 131 are used to clamp the end portions 232 of the isolation membrane 230 .

[0110] The pair of second clamping parts 131 clamp the isolation film 230 from both sides in the thickness direction of the isolation film 230 . The pair of second clamping parts 131 may be a pair of pneumatic fingers or electric fingers.

[0111] In the above solution, a pair of second clamping portions 131 are used to clamp the end portion 232 of the isolation membrane 230 , which can reliably fix the end portion 232 of the isolation membrane 230 , and the traction member 121 can reliably pull out the protruding section 231 of the isolation membrane 230 to a preset length.

[0112] In some embodiments of the present application, the traction member 121 is a movable pulley.

[0113] Specifically, the central axis of the traction member 121 extends along the width direction of the isolation diaphragm 230 , and both axial ends of the traction member 121 exceed both width directions of the isolation diaphragm 230 to uniformly act on the isolation diaphragm 230 along the width of the isolation diaphragm 230 .

[0114] In the above solution, the traction member 121 is set as a movable pulley. During the movement of the traction member 121 pushing the isolation membrane 230, the traction member 121 can automatically adjust the contact angle relative to the surface of the isolation membrane 230 by rotating around its axis to avoid scratching the isolation membrane 230.

[0115] Figure 8 Shown is Figure 3 A schematic structural diagram of a winding device further provided with a fixed pulley (the driving member is not shown); Figure 9 Shown is Figure 7 The winding device in the embodiment is further provided with a structural diagram of a fixed pulley.

[0116] like Figure 8 and Figure 9 As shown, in some embodiments of the present application, the winding device 100 further includes a fixed pulley 140 , which is disposed between the winding component 110 and the traction member 121 and is used to guide the movement of the isolation film 230 .

[0117] The fixed pulley 140 extends axially along the width direction of the isolation diaphragm 230 . Both ends of the fixed pulley 140 in the axial direction extend beyond the isolation diaphragm 230 to uniformly act on the isolation diaphragm 230 along the width direction of the isolation diaphragm 230 .

[0118] like Figure 8As shown, based on the aforementioned embodiment in which the traction member 121 pulls the end portion 232 of the isolation film 230 to move, the exiting section 231 of the isolation film 230 changes its direction of travel after passing around the fixed pulley 140. During the rotation of the winding component 110, the direction of travel of the portion of the isolation film 230 from the fixed pulley 140 to the traction member 121 remains fixed. Figure 9 As shown, based on the aforementioned implementation method in which the fixing member 130 fixes the end portion 232 of the isolation membrane 230 and the traction member 121 pushes the portion of the isolation membrane 230 between the winding member 110 and the fixing member 130, the passing section 231 of the isolation membrane 230 changes its direction of travel after passing around the fixed pulley 140. During the rotation of the winding member 110, the traction member 121 pushes the isolation membrane 230 to pull out the passing section 231 of the isolation membrane 230, and the position of the portion of the isolation membrane 230 that passes through the fixed pulley 140 and the portion that is fixed to the fixing member 130 remain fixed.

[0119] In the above scheme, by arranging a fixed pulley 140 between the winding component 110 and the traction component 121, the running direction of the isolation membrane 230 can be guided and changed, reducing the impact of the rotation process of the winding component 110 on the outlet section 231, which is beneficial to controlling the running direction of the outlet section 231 from the fixed pulley 140 to the end 232 of the isolation membrane 230. It is not only beneficial to calculate the length of the outlet section 231, but also can improve the working reliability of the winding equipment 100.

[0120] Figure 10 Shown is a process flow chart of the winding method according to some embodiments of the present application.

[0121] like Figure 10 As shown, some embodiments of the present application further provide a winding method for winding an electrode assembly 200, the winding method comprising:

[0122] S100: The isolation film 230 is passed through the winding component 110. The portion of the isolation film 230 that passes through the winding component 110 is the passing-out section 231.

[0123] S200: pulling the outgoing section 231 of the isolation film 230 so that the length of the outgoing section 231 reaches a preset value;

[0124] S300 : The winding unit 110 starts winding to form the electrode assembly 200 .

[0125] For ease of description, the present embodiment of the present application illustrates the winding method of the present embodiment in conjunction with the method of using the winding device 100. It is understood that the winding method of the present embodiment of the present application includes but is not limited to being implemented using the winding device 100 of the present embodiment of the present application.

[0126] S100: The isolation film 230 is passed through the winding component 110. The portion of the isolation film 230 that passes through the winding component 110 is the passing-out section 231, which includes:

[0127] The isolation film 230 enters the gap 112 between the pair of winding needles 111 from the first end 1121 and passes through the gap 112 from the second end 1122 . The portion of the isolation film 230 from the second end 1122 to the end 232 is the passing-out section 231 .

[0128] In some embodiments of the present application, S200: pulling the outgoing section 231 of the isolation film 230 so that the length of the outgoing section 231 reaches a preset value includes:

[0129] S210: The pulling member 121 moves from the first position to the second position to pull the passing section 231, so that the length of the passing section 231 reaches a preset value.

[0130] In some embodiments of the present application, S210: the pulling member 121 moves from the first position to the second position to pull the exit section 231 so that the length of the exit section 231 reaches a preset value, including:

[0131] S211: The traction member 121 includes a pair of first clamping portions 1211, which are used to clamp the end portion 232 of the isolation membrane 230. The traction member 121 moves from the first position to the second position so that the length of the protruding section 231 reaches a preset value.

[0132] In some other embodiments of the present application, S210: the pulling member 121 moves from the first position to the second position to pull the exit section 231 so that the length of the exit section 231 reaches a preset value, including:

[0133] S212: The traction member 121 is a movable pulley, and the fixing member 130 is used to fix the end 232 of the isolation membrane 230. The traction member 121 pushes the part between the winding part 110 and the fixing member 130 of the isolation membrane 230 and moves from the first position to the second position so that the length of the protruding section 231 reaches a preset value.

[0134] In some embodiments of the present application, S200: pulling the outgoing section 231 of the isolation film 230 so that the length of the outgoing section 231 reaches a preset value includes:

[0135] S220 : A fixed pulley 140 is provided between the winding component 110 and the traction component 121 . After the isolation film 230 passes through the second end 1122 of the gap 112 of the winding component 110 , it first passes around the fixed pulley 140 and is then pulled by the traction component 121 .

[0136] In some embodiments of the present application, S300: the winding component 110 starts winding to form the electrode assembly 200, including:

[0137] S310: The traction member 121 returns from the second position to the first position, and provides tension to the isolation film 230 during the process of returning to the first position;

[0138] S320 : When the pulling member 121 returns to the first position, the pulling member 121 releases the isolation film 230 .

[0139] In step S212 , the traction member 121 is a movable pulley, and the end portion 232 of the separator 230 is fixed by the fixing member 130 . The traction member 121 pushes the portion of the separator 230 between the winding member 110 and the fixing member 130 and moves from the first position to the second position so that the length of the protruding portion 231 reaches a preset value. In step S300 , the winding member 110 starts winding to form the electrode assembly 200 . The process further includes:

[0140] S330 : When the pulling member 121 returns to the first position, the fixing member 130 releases the end portion 232 of the isolation film 230 .

[0141] The electrode assembly 200 is wound and formed using the winding method of the embodiment of the present application. The protruding section 231 of the isolation membrane 230 with a preset length can also be wound into the winding part 110, so that the protruding section 231 of the isolation membrane 230 and the isolation membrane 230 newly entering the winding part 110 are stacked so that the isolation membrane 230 between the inner circle of the negative electrode plate 210 and the positive electrode plate 220 has a multi-layer isolation membrane. When lithium plating occurs, lithium dendrites are not easy to pierce the isolation membrane, causing the negative electrode plate 210 and the positive electrode plate 220 to contact and thus cause an internal short circuit in the electrode assembly 200. The electrode assembly 200 wound and formed using this winding method has higher safety performance.

[0142] In some embodiments of the present application, a preset value of the length of the passing-out section 231 is greater than the circumference of the winding component 110 .

[0143] Please refer to Figure 1As shown, based on the aforementioned embodiment in which the first end 1121 and the second end 1122 of the gap 112 are located on opposite radial sides of the winding member 110, the winding member 110 begins to rotate after the length of the protrusion section 231 reaches a predetermined value. The protrusion section 231, starting from the starting end 2311, first directly contacts the winding member for half the circumference, until it is stacked with the first separator 233 in the separator 230. After the negative electrode sheet 210 is inserted between the first separator 233 and the second separator 234 to enter the winding member 110, the outer side of the negative electrode sheet 210 is further stacked with the protrusion section 231 on top of the original first separator 233, i.e., the number of separator layers of the negative electrode sheet 210 is three. After the positive electrode sheet 220 enters the winding component 110 from the inner side of the second separator 234, it is positioned opposite the outer side of the previously wound negative electrode sheet 210. That is, there are three layers of separator between the innermost circle of the positive electrode sheet 220 and the negative electrode sheet 210 inside it. The exit section 231 continues to laminate for half the circumference of the winding component 110, covering the first bend 235 of the innermost circle of the positive electrode sheet 220. This protects the first bend 235 of the innermost circle of the positive electrode sheet 220 from shorting the electrode assembly 200 in the event of lithium deposition.

[0144] In the above solution, the preset value of the through section 231 is greater than the circumference of the winding component 110, and can be at least in the first bending area 235 of the innermost circle of the positive electrode sheet 220 (see Figure 2 ) and the inner negative electrode sheet 210 are provided with a multi-layer isolation film, thereby preventing the first bending area 235 of the innermost circle of the positive electrode sheet 220 (see Figure 2 ) when lithium deposition occurs on the inner side, the lithium crystallization pierces the isolation membrane, which can significantly improve the safety performance of the electrode assembly 200.

[0145] In other embodiments, when it is necessary to protect the first and second bending zones 235 of the innermost circle of the positive electrode plate 220 from being affected by lithium plating, the preset value can be greater than 1.5 times the circumference of the winding component 110; and so on, along the direction of the positive electrode plate 220 winding outward from the innermost circle, for each additional bending zone 235 protected, the length of the preset value increases by one circumference of the winding component, and no examples are given in this article.

[0146] Figure 11 Shown is Figure 3 Schematic diagram of the winding process of the winding equipment; Figure 12 Shown is Figure 7 Schematic diagram of the winding process of the winding equipment.

[0147] like Figures 1 to 6 as well as Figure 11As shown, some embodiments of the present application provide a winding device 100 for winding an electrode assembly 200. The winding device 100 includes a winding component 110, a traction mechanism 120, and a fixed pulley 140. The traction mechanism 120 includes a traction member 121. The fixed pulley 140 is fixedly disposed below the winding component 110. The traction member 121 can move between a first position and a second position. The traction member 121 includes a pair of first clamping portions 1211. The isolation film 230 passes through the winding component 110 and then around the fixed pulley 140. The traction member 121 moves below the fixed pulley 140 to pull out the exit section 231 of the isolation film 230.

[0148] The winding method of the winding device 100 is as follows:

[0149] The isolation film 230 passes through the winding component 110 , and the end portion 232 is exposed from the winding component 110 ;

[0150] Before the winding member 110 starts winding, the pair of first clamping portions 1211 of the traction member 121 clamp the end portion 232 of the isolation film 230;

[0151] The traction member 121 drives the end portion 232 of the isolation film 230 to move along the first sub-direction Q1 from the first position to the second position, pulling the isolation film 230 out until the length of the protruding portion 231 reaches a preset value, wherein the preset value is L1 + L2, and the preset value is greater than the circumference of the winding member 110.

[0152] The winding component 110 starts to wind along the first direction P. At the same time, the pulling member 121 clamps the end portion 232 of the isolation film 230 and moves backward along the second sub-direction Q2 to tension the exit section 231 of the isolation film.

[0153] After the traction member 121 returns to the first position, the traction member 121 releases the end portion 232 of the separator 230 , and the winding member 110 continues to wind the entire protruding section 231 into the winding member 110 , thereby obtaining an electrode assembly 200 with a special structure.

[0154] like Figures 7 to 9 as well as Figure 12As shown, some embodiments of the present application provide a winding apparatus 100 for winding an electrode assembly 200. The winding apparatus 100 includes a winding member 110, a traction mechanism 120, a fixed member 130, and a fixed pulley 140. The traction mechanism 120 includes a traction member 121, which is fixedly disposed below the winding member 110 and can move between a first position and a second position. The traction member 121 is a movable pulley. The separator 230 passes through the winding member 110 and then around the fixed pulley 140. The fixed member 130 is fixedly disposed below the fixed pulley 140 and includes a pair of second clamping portions 131 for clamping an end portion 232 of the separator 230. The traction member 121 is disposed between the fixed member 130 and the fixed pulley 140 and can push against the separator 230 to pull out the exit portion 231 of the separator 230.

[0155] The method of using the winding device 100 is as follows:

[0156] The isolation film 230 passes through the winding component 110 , and the end portion 232 is exposed from the winding component 110 ;

[0157] Before the winding component 110 starts winding, the fixing member 130 fixes and clamps the end portion 232 of the isolation film 230;

[0158] The traction member 121 pushes the portion of the isolation film 230 between the fixed pulley 140 and the fixed member 130 and moves along the first sub-direction Q1 from the first position to the second position to pull the isolation film 230 out of the winding member 110 until the length of the protruding section 231 reaches a preset value, wherein the preset value is L1+L3+L4, and the preset value is greater than the circumference of the winding member 110.

[0159] The winding member 110 begins to wind along the first direction P. At the same time, the pulling member 121 pushes against the isolation film 230 and moves backward along the second sub-direction Q2 to tension the exit section 231 of the isolation film 230.

[0160] After the traction member 121 returns to the first position, the traction member 121 releases the isolation film 230, the fixing member 130 releases the end 232 of the isolation film 230, and the winding member 110 continues to wind to completely roll the protruding section 231 into the winding member 110, thereby obtaining an electrode assembly 200 with a special structure.

[0161] The winding device 100 of the embodiment of the present application includes a winding part 110 and a traction mechanism 120, which can stretch the length of the protruding section 231 of the isolation film 230 to a preset value. The winding part 110 can be wound into the protruding section 231 when winding, forming an electrode assembly 200 with a special structure. There are multiple layers of isolation films between the innermost circle of the positive electrode plate 220 of the electrode assembly 200 and the negative electrode plate 210 inside it, which can prevent lithium crystallization from short-circuiting the positive electrode plate 220 and the negative electrode plate 210 when lithium is deposited there, resulting in a short circuit inside the electrode assembly 200, and has high safety performance. Using the winding device 100 and the winding method to wind and form the electrode assembly 200 can not only realize the industrial production of the electrode assembly 200, but also improve the manufacturing efficiency of the electrode assembly 200.

[0162] It should be noted that, unless there is any conflict, the features in the embodiments of this application can be combined with each other.

[0163] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A winding device for winding a positive electrode sheet, a negative electrode sheet, a first separator and a second separator to form an electrode assembly, characterized in that: The winding device comprises: winding components; a traction mechanism, the traction mechanism being configured to pull the passing-out sections of the first and second isolation films after the first and second isolation films pass through the winding component, so that the lengths of the passing-out sections of the first and second isolation films reach a preset value; The winding component is configured to start winding after the length of the protruding sections of the first separator and the second separator reaches the preset value, so as to form the electrode assembly; The traction mechanism includes a traction member and a driving member, wherein the driving member is used to drive the traction member to move between a first position and a second position, and the traction member is configured to pull the first isolation membrane and the second isolation membrane during the process of moving from the first position to the second position; The traction member is configured to return from the second position to the first position after the winding member starts winding, and provide tension to the first isolation film and the second isolation film during the process of returning to the first position; The pulling member is configured to return from the second position to the first position after the winding component starts winding, and release the first separation film and the second separation film when returning to the first position.

2. The winding device according to claim 1, characterized in that When the pulling member is in the first position, the pulling member is located below the winding member along the direction of gravity.

3. The winding device according to claim 2, characterized in that The moving direction of the traction member intersects with the direction of gravity.

4. The winding device according to any one of claims 1 to 3, characterized in that: The traction member includes a pair of first clamping portions, and the pair of first clamping portions are used to clamp the ends of the first isolation diaphragm and the second isolation diaphragm.

5. The winding device according to any one of claims 1 to 3, characterized in that: The winding device also includes: a fixing member for fixing the ends of the first isolation diaphragm and the second isolation diaphragm, wherein the fixing member is configured to release the ends of the first isolation diaphragm and the second isolation diaphragm when the pulling member returns to the first position; The pulling member is configured to push the first isolation membrane and the second isolation membrane at portions located between the fixing member and the winding component.

6. The winding device according to claim 5, characterized in that The fixing member includes a pair of second clamping portions, and the pair of second clamping portions are used to clamp the ends of the first isolation diaphragm and the second isolation diaphragm.

7. The winding device according to claim 5, characterized in that The traction member is a movable pulley.

8. The winding device according to claim 1, characterized in that The winding device also includes: A fixed pulley is provided between the winding component and the traction component, and is used for guiding the movement of the first isolation diaphragm and the second isolation diaphragm.

9. A winding method using the winding device according to any one of claims 1 to 8, for winding an electrode assembly, characterized in that: The winding method comprises: Passing the first and second isolation films through the winding component, wherein the portions of the first and second isolation films that pass through the winding component are exiting sections; pulling the protruding sections of the first isolation membrane and the second isolation membrane so that the lengths of the protruding sections of the first isolation membrane and the second isolation membrane reach a preset value; The winding member begins to be wound to form the electrode assembly.

10. The winding method according to claim 9, characterized in that The preset value is greater than the circumference of the winding component.

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