A method for manufacturing an electrode assembly and a battery cell

Abstract

The present application discloses a manufacturing method of an electrode assembly and a battery cell, and relates to the field of battery technology. The manufacturing method of the electrode assembly can reduce the risk of wrinkles or gaps forming in the electrode assembly, which is beneficial to improving the service life of the battery. The manufacturing method includes: connecting one end of the electrode assembly to the winding assembly; controlling the winding assembly to rotate, winding the electrode assembly to form a wound electrode assembly; controlling the winding assembly to withdraw from the wound electrode assembly, and placing the wound electrode assembly on a rolling device; controlling two groups of stretching assemblies to at least partially move into the wound electrode assembly, and abut against the two inner sides of the wound electrode assembly opposite to each other along the first direction; controlling the two groups of stretching assemblies to move in opposite directions at least twice in the first direction, and controlling the rolling device to apply a force to the wound electrode assembly along the second direction to stretch and press the wound electrode assembly on at least one side; the second direction is perpendicular to the first direction.

Description

Technical Field

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

[0002] With the rapid development of the lithium battery industry, the production efficiency of the electrode assembly in the battery is required to be higher and higher, and the production cost needs to be reduced. The method of forming the electrode assembly by winding is widely used in the production process of square lithium-ion electrode assemblies due to its high efficiency and low cost.

[0003] In the process of producing a square lithium-ion electrode assembly, the electrode assembly needs to be first wound to form a cylindrical electrode assembly, and then the cylindrical electrode assembly needs to be shaped to obtain an approximately square electrode assembly. In the related art, after the cylindrical electrode assembly is shaped, wrinkles are easily formed in the innermost circle of the wound approximately square electrode assembly, or a gap is generated between the electrode sheet and the separator in the electrode assembly, thereby affecting the service life of the battery. Summary of the invention

[0004] The present application provides a method for manufacturing an electrode assembly and a battery cell, which can reduce the risk of wrinkles or gaps forming in the electrode assembly, thereby helping to increase the service life of the battery.

[0005] The first aspect of the present application provides a method for manufacturing an electrode assembly, which is applied to an electrode assembly manufacturing device, wherein the electrode assembly manufacturing device includes a winding assembly, a pressing device and two groups of stretching assemblies; the manufacturing method includes: connecting one end of the electrode assembly to the winding assembly; controlling the rotation of the winding assembly to wind the electrode assembly to form a wound electrode assembly; controlling the winding assembly to withdraw from the wound electrode assembly and placing the wound electrode assembly on the pressing device; controlling the two groups of stretching assemblies to at least partially move into the wound electrode assembly and to abut against the two inner sides of the wound electrode assembly opposite to each other along a first direction; controlling the two groups of stretching assemblies to move away from each other at least twice in the first direction, and controlling the pressing device to apply a force to the wound electrode assembly along a second direction to stretch and press the wound electrode assembly on at least one side; the second direction is perpendicular to the first direction.

[0006] The manufacturing method of the electrode assembly provided in the embodiment of the present application connects one end of the electrode assembly to the winding assembly, so that the winding assembly drives the electrode assembly to be wound during the rotation process, so as to complete the winding of the long strip electrode assembly. And the obtained wound electrode assembly is placed on a rolling device, and the cylindrical wound electrode assembly can be flattened and shaped by the rolling device. At the same time, in the process of flattening and shaping the cylindrical wound electrode assembly by the rolling device, two groups of stretching assemblies are also controlled to stretch the wound electrode assembly from the inside, so that the inner circle of the wound electrode assembly can be stretched flat, and a force along the first direction can be applied to the bent part of the flattened wound electrode assembly, which is conducive to making the various layers of the bent part of the wound electrode assembly fit closely, thereby reducing the risk of wrinkles or gaps in the wound electrode assembly obtained after flattening and shaping, which is conducive to improving the quality of the wound electrode assembly obtained, and then the service life of the battery using the wound electrode assembly can be improved.

[0007] In a possible implementation of the present application, the two groups of supporting and pulling components are controlled to move away from each other at least twice in a first direction, and the pressing and rolling device is controlled to apply a force to the wound electrode assembly along a second direction, including: after controlling the two groups of supporting and pulling components to move away from each other in the first direction each time, controlling the pressing and rolling device to apply a force to the wound electrode assembly along the second direction at least once.

[0008] In the technical solution of the present application, after the wound electrode assembly is stretched once by the stretching assembly, the wound electrode assembly is pressed at least once by the pressing device, so that the electrode assembly in the inner layer of the wound electrode assembly can be stretched multiple times, which is beneficial to reduce the occurrence of wrinkles in the wound electrode assembly.

[0009] In a possible implementation of the present application, the rolling device includes a supporting platform and a pressing piece arranged relatively to each other, and the wound electrode assembly is supported on the supporting platform; after each opposite movement of the two groups of supporting and stretching assemblies in the first direction, the rolling device is controlled to apply a force to the wound electrode assembly along the second direction, including: determining the opening distance of the two groups of supporting and stretching assemblies based on the length of the winding starting section in the wound electrode assembly; the winding starting section is a section of the electrode assembly located in the innermost layer of the wound electrode assembly; based on the opening distance, the clamping pieces corresponding to the two groups of supporting and stretching assemblies are controlled to synchronously generate reverse movement along the first direction to support and stretch the wound electrode assembly; the pressing piece is controlled to move along the second direction toward the direction close to the wound electrode assembly until the pressing piece abuts against the wound electrode assembly.

[0010] In the technical solution of the present application, since the two groups of stretching assemblies are controlled to move in opposite directions along the first direction according to the opening distance of the two groups of stretching assemblies, the cylindrical wound electrode assembly can be stretched into a flat shape along the first direction by the two groups of stretching assemblies to complete the one-time shaping of the wound electrode assembly. Moreover, in the process of the two groups of stretching assemblies stretching the wound electrode assembly, since the force is applied from the inside of the wound electrode assembly to the outside of the wound electrode assembly, the various layers of the internal structure of the wound electrode assembly can be stretched flat, which is conducive to reducing the wrinkles and gaps caused by the force on various parts of the wound electrode assembly.

[0011] In a possible implementation of the present application, each group of supporting and pulling assemblies includes an inner clamping member and an outer clamping member, the inner clamping member is abutted against the inner side of the wound electrode assembly, and the outer clamping member is abutted against the outer side of the wound electrode assembly; after the step of controlling the pressing member to move along the second direction toward the direction close to the wound electrode assembly until the pressing member abuts against the wound electrode assembly, the method for manufacturing the electrode assembly also includes: controlling the first clamping member to move along the first direction toward the direction away from the wound electrode assembly; the first clamping member is the outer clamping member of the two outer clamping members that is close to the free end of the winding starting section; controlling the pressing member to move along the second direction toward the direction close to the wound electrode assembly by a first preset distance; controlling the inner clamping member to move along the second direction toward the direction close to the supporting platform by a second preset distance; controlling the two inner clamping members to move in the opposite direction of the preset supporting and pulling distance along the first direction.

[0012] In the technical solution of the present application, since the pressing member is controlled to move the wound electrode assembly along the second direction, the wound electrode assembly can be flattened and shaped by the pressing member and the carrier, which is conducive to making the layers of the wound electrode assembly fit more closely. And the inner clamping member is controlled to move along the first direction to produce a preset stretching distance, and the layers on the inner side of the wound electrode assembly can be stretched again by the inner clamping member, so that the bent part of the wound electrode assembly after flattening can be stretched flat, which is conducive to reducing wrinkles or gaps in the wound electrode assembly.

[0013] In a possible implementation of the present application, after the step of controlling the two winding shaping members to produce reverse movement of a preset stretching distance along the first direction, the manufacturing method of the electrode assembly also includes: controlling the pressing member to move a third preset distance along the second direction toward the direction close to the wound electrode assembly and maintaining it for a preset time; controlling the second clamping member to move along the first direction toward the direction away from the wound electrode assembly; the second clamping member is the clamping member of the two clamping members that is away from the free end of the winding starting section; controlling the two inner clamping members to withdraw from the wound electrode assembly; controlling the pressing member to move along the second direction toward the direction close to the wound electrode assembly until the winding starting section is in contact with the adjacent electrode assembly.

[0014] In the technical solution of the present application, before controlling the pressing part to completely flatten the wound electrode assembly, the pressing part is first controlled to flatten and shape the wound electrode assembly again by a smaller distance. This can effectively reduce the extrusion deformation and extrusion stress generated in the inner circle of the wound electrode assembly, thereby reducing the tiny wrinkles and gaps generated between the various layer structures in the wound electrode assembly, which is beneficial to improving the quality of the wound electrode assembly.

[0015] In a possible implementation of the present application, the two groups of supporting and pulling assemblies are controlled to move in opposite directions at least twice in a first direction, and the pressing and rolling device is controlled to apply a force to the wound electrode assembly along a second direction, including: controlling the pressing and rolling device to apply a force to the wound electrode assembly along the second direction; controlling the two groups of supporting and pulling assemblies to produce reverse movement along the first direction while controlling the two groups of supporting and pulling assemblies to produce movement along the second direction so that the two groups of supporting and pulling assemblies remain on the symmetry line of the wound electrode assembly; the symmetry line is parallel to the first direction.

[0016] In the technical solution of the present application, since the two groups of stretching assemblies are controlled to move in the first direction while the rolling device is controlled to flatten and reshape the wound electrode assembly, the inner circle of the flattened wound electrode assembly can be stretched by the stretching assemblies, which is conducive to keeping the inner circle of the wound electrode assembly flat, and can keep the layers of the structure at the corners of the wound electrode assembly tightly fitted under the force applied by the stretching assemblies, thereby reducing the risk of wrinkles or gaps in the wound electrode assembly, which is conducive to improving the quality of the wound electrode assembly.

[0017] In a possible implementation of the present application, the winding assembly includes a first winding member and a second winding member, and a receiving cavity extending in the radial direction of the winding assembly is formed between the first winding member and the second winding member, and the first winding member and the second winding member have a receiving groove on the circumferential surface respectively, and the two receiving grooves are located on the same diameter of the winding assembly, and each group of supporting and pulling assemblies includes an inner clamping member located in the wound electrode assembly, and the two inner clamping members are respectively accommodated in the two receiving grooves; one end of the electrode assembly is connected to the winding assembly, including: based on the length of the winding starting section in the wound electrode assembly, adjusting the structural form of the winding assembly and the two inner clamping members to a winding posture; the winding starting section is a section of the electrode assembly located in the innermost layer of the wound electrode assembly; at least a portion of the winding starting section is placed in the receiving cavity in the winding posture to connect the electrode assembly to the winding assembly.

[0018] In the technical solution of the present application, since the structural forms of the winding assembly and the two inner clamping members are adjusted according to the length of the winding starting section, the circumference of the winding assembly can be matched with the length of the winding starting section of the wound electrode assembly, thereby improving the dimensional accuracy of the wound electrode assembly formed by winding, and further improving the processing quality of the wound electrode assembly.

[0019] In a possible implementation of the present application, based on the length of the winding starting section in the wound electrode assembly, the structural form of the winding assembly and the two inner clamping members is adjusted to a winding posture, including: based on the length of the winding starting section, adjusting the accommodation distance between the first winding member and the second winding member; the direction of the accommodation distance satisfies a perpendicular relationship with the extension direction of the accommodation cavity.

[0020] In the technical solution of the present application, since the theoretical accommodation distance between the first winding member and the second winding member is determined according to the length of the starting section of the winding, and the actual accommodation distance between the first winding member and the second winding member is adjusted based on the determined accommodation distance, the circumference of the winding assembly can be made nearly consistent with the length of the starting section of the wound electrode assembly, thereby improving the dimensional accuracy of the wound electrode assembly formed by winding the winding assembly.

[0021] In a possible implementation of the present application, based on the length of the winding starting section in the wound electrode assembly, the structural form of the winding assembly and the two inner clamping members are adjusted to a winding posture, and also includes: based on the length of the winding starting section, adjusting the phase angle between the inner clamping member and the accommodating section in the winding starting section located in the accommodating cavity; the phase angle is the angle between the inner clamping member and the accommodating section along the circumferential direction of the winding assembly; placing at least a portion of the winding starting section in the accommodating cavity in a winding posture, including: passing the winding starting section into the accommodating cavity from the first end of the accommodating cavity, and extending until at least a portion of the winding starting section passes through the inner clamping member in the first accommodating groove; the first accommodating groove is the second end of the two accommodating grooves close to the accommodating cavity; the first end and the second end are respectively the two ends of the accommodating cavity along the radial direction of the wound electrode assembly.

[0022] In the technical solution of the present application, since the phase angle between the inner clamping member and the accommodating section is adjusted according to the length of the winding start section, the path length between the two inner clamping members can be adjusted quickly and conveniently. In addition, the phase angle between the inner clamping member and the accommodating section is easier to control and accurately adjust, so that the actual winding start section length of the inner clamping member obtained can be consistent or nearly consistent with the desired winding start section length, which is beneficial to control the dimensional accuracy of the winding process of the wound electrode assembly.

[0023] A second aspect of the present application provides a battery cell, the battery cell comprising an electrode assembly formed by any one of the electrode assembly manufacturing methods provided in the first aspect.

[0024] The battery cell provided in the present application includes an electrode assembly obtained by winding and shaping through the electrode assembly manufacturing method provided by any one of the first aspects above. Therefore, the risk of wrinkles or gaps forming in the electrode assembly obtained after flattening and shaping can be reduced, which is beneficial to improving the quality of the obtained electrode assembly and further improving the service life of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0026] Figure 1 The structure of the electrode assembly manufacturing device provided in this application is schematically shown Figure 1 ;

[0027] Figure 2 The structure of the electrode assembly manufacturing device provided in this application is schematically shown Figure 2 ;

[0028] Figure 3 Schematic diagram of the manufacturing method of the electrode assembly provided in this application Figure 1 ;

[0029] Figure 4 A schematic diagram of the electrode assembly manufacturing device provided in the present application for winding and processing an electrode assembly;

[0030] Figure 5 Schematic diagram of the manufacturing method of the electrode assembly provided in this application Figure 2 ;

[0031] Figure 6 Schematic diagram of the manufacturing method of the electrode assembly provided in this application Figure 3 ;

[0032] Figure 7 A schematic diagram of the process of stretching, pressing and shaping the wound electrode assembly provided in this application;

[0033] Figure 8 This is a schematic diagram of the structure of the wound electrode assembly obtained after stretching, pressing and shaping provided in the present application;

[0034] Fig. 9 Schematic diagram of the manufacturing method of the electrode assembly provided in this application Figure 4 ;

[0035] Fig.10 Schematic diagram of the manufacturing method of the electrode assembly provided in this application Figure 5 ;

[0036] Fig.11 Schematic diagram of the manufacturing method of the electrode assembly provided in this application Figure 6 ;

[0037] Fig.12 Schematic diagram of the manufacturing method of the electrode assembly provided in this application Figure 7 ;

[0038] Fig.13 Schematic diagram of the manufacturing method of the electrode assembly provided in this application Figure 8 ;

[0039] Fig.14 Schematic diagram of the manufacturing method of the electrode assembly provided in this application Figure 9 .

[0040] Description of reference numerals:

[0041] 1-winding assembly; 11-first winding member; 12-second winding member; 13-accommodating chamber; 14-accommodating groove; 2-supporting and pulling assembly; 21-inner clamping member; 22-outer clamping member; 221-first clamping member; 222-second clamping member; 3-rolling device; 31-carrying platform; 32-pressing member; 5-winding electrode assembly; 51-winding starting section; 511-free end; 52-accommodating section; 53-positive electrode; 54-negative electrode; ΔL-accommodating distance; Y-first direction; E-second direction; Z-circumferential direction; S-symmetry line; L1-winding starting section length; θ-phase angle. DETAILED DESCRIPTION

[0042] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification of this application and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions.

[0044] In the description of the embodiments of the present application, the technical terms "first", "second", "third", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0045] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0046] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0047] In the description of the embodiments of the present application, the orientation or position relationship indicated by technical terms such as "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", and "circumferential" are based on the orientation or position relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed, operated or used in a specific orientation. Therefore, they should not be understood as limitations on the embodiments of the present application.

[0048] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0049] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, the technical term "contact" should be understood in a broad sense, and may be direct contact or contact through an intermediate medium layer. It may be contact with essentially no interaction force between the two contacting parties, or it may be contact with interaction force between the two contacting parties.

[0050] At present, new energy batteries are increasingly used in life and industry. New energy batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but are also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars, as well as aerospace and other fields. With the continuous expansion of the application field of power batteries, the market demand is also constantly expanding.

[0051] In the process of producing the electrode assembly in the battery, a winding method with high production efficiency and low production cost is usually adopted. For example, the positive electrode, separator and negative electrode in the electrode assembly are stacked in sequence, and the stacked positive electrode, separator and negative electrode are wound by the winding assembly to form a cylindrical wound electrode assembly. The cylindrical wound electrode assembly is then flattened and shaped by a rolling device to obtain a wound battery cell for a square battery.

[0052] The winding assembly is the main part of the electrode assembly. Due to the thickness of the incoming materials of the pole piece and the separator, as well as the differences in the winding assembly, in the process of winding the electrode assembly to obtain the wound electrode assembly, the length of the pole piece in the inner circle of the wound electrode assembly is not fixed, which leads to the misalignment of the pole ear on the electrode assembly, and after the cylindrical wound electrode assembly is flattened and shaped, the inner circle of the obtained wound battery cell is prone to wrinkles, or the gap between the positive pole piece and the negative pole piece at the corner of the inner circle of the wound battery cell is too large, which leads to lithium deposition problems or pole piece wrinkles at the corner of the wound battery cell, which in turn affects the safety and service life of the battery. Therefore, it is necessary to solve the problem of wrinkles or gaps in the wound battery cell.

[0053] The present application provides an electrode assembly manufacturing device, referring to Figure 1 and Figure 2 , Figure 1 The structure of the electrode assembly manufacturing device provided in this application is schematically shown Figure 1 , Figure 2 The structure of the electrode assembly manufacturing device provided in this application is schematically shown Figure 2 . The electrode assembly manufacturing device includes: a winding assembly 1, a stretching assembly 2 and a pressing device 3. Among them, the stretching assembly 2 includes an inner clamping member 21 and an outer clamping member 22, and the inner clamping member 21 can cooperate with the winding assembly 1 to jointly complete the winding of the electrode assembly to form a cylindrical wound electrode assembly 5. The inner clamping member 21 and the outer clamping member 22 cooperate to complete the stretching and shaping of the cylindrical wound electrode assembly 5, so as to shape the cylindrical wound electrode assembly 5 into a flat cylindrical wound electrode assembly 5. The pressing device 3 can complete the flattening and shaping of the cylindrical wound electrode assembly 5, so as to shape the flat cylindrical wound electrode assembly 5 into an approximately square wound battery cell.

[0054] For example, Figure 1 As shown, the winding assembly 1 includes a first winding member 11 and a second winding member 12. The first winding member 11 and the second winding member 12 can be both configured to have an overall shape that is approximately a semi-cylindrical structure, that is, the first winding member 11 and the second winding member 12 can form a cylinder after being combined. The first winding member 11 and the second winding member 12 can be connected in the radial direction through a radial drive assembly to adjust the radial accommodation distance ΔL of the accommodating cavity 13 between the first winding member 11 and the second winding member 12, and thus the circumference of the winding assembly 1 in the circumferential direction Z can be adjusted.

[0055] Another example, such as Figure 1 As shown, a receiving groove 14 can be provided on both the first winding member 11 and the second winding member 12. The receiving groove 14 is located on the circumferential surface of the first winding member 11 and the second winding member 12 and extends along the axial direction of the winding assembly 1 ( Figure 1 The inner clamping member 21 is connected to the first winding member 11 and the second winding member 12 in the direction perpendicular to the paper plane. Then, the two inner clamping members 21 can be respectively accommodated in the two accommodating grooves 14. Among them, the cross section of the accommodating groove 14 is larger than the cross section of the inner clamping member 21, so that the inner clamping member 21 can move along the circumferential direction Z in the accommodating groove 14, and the distance between the inner clamping member 21 and the accommodating cavity 13 can be adjusted.

[0056] Another example, Figure 2 As shown, a rolling device 3 can be provided in the electrode assembly manufacturing device, so that the rolling device 3 applies pressure to the cylindrical wound electrode assembly 5 that has been wound in the radial direction, so as to flatten and shape the cylindrical wound electrode assembly 5. For example, the rolling device 3 includes a carrier 31 and a pressing member 32. The carrier 31 can be set as a platform extending along the horizontal plane, and the pressing member 32 can be set above the carrier 31 in the vertical direction, and a driving member can be provided for the pressing member 32, and the driving member drives the pressing member 32 to move in a direction away from or close to the carrier 31. In this way, the cylindrical wound electrode assembly 5 can be placed on the carrier 31, and the pressing member 32 can be controlled to move in a direction close to the carrier 31, so as to apply a force in the radial direction to the cylindrical wound electrode.

[0057] Another example, such as Figure 2As shown, two groups of support and tensioning assemblies 2 can be set in the electrode assembly manufacturing device, one group of support and tensioning assemblies 2 includes an inner clamping member 21 and a first clamping member 221, and the other group of support and tensioning assemblies 2 includes another inner clamping member 21 and a second clamping member 222. Among them, the first clamping member 221 and the second clamping member 222 are two outer clamping members 22 respectively. In this way, in the process of shaping the wound electrode assembly 5, the two inner clamping members 21 can be located in the cavity inside the wound electrode assembly 5, the two outer clamping members 22 can be located on the outside of the wound electrode assembly 5 respectively, and the inner clamping members 21 and the outer clamping members 22 are distributed along the radial direction of the wound electrode assembly 5. As shown Figure 2 As shown, a portion of the wound electrode assembly 5 can be clamped by the first clamping member 221 and an inner clamping member 21, while another portion of the wound electrode assembly 5 can be clamped by the second clamping member 222 and another inner clamping member 21. In this way, by controlling one group of stretching assemblies 2 to move in a radial direction away from another group of stretching assemblies 2, the wound electrode assembly 5 can be stretched in a radial direction, so that the cylindrical wound electrode assembly 5 is transformed into a flat wound electrode assembly 5.

[0058] In addition, the present application also provides a method for manufacturing an electrode assembly, which is applied to an electrode assembly manufacturing device, wherein the electrode assembly manufacturing device includes a winding assembly 1, a rolling device 3, and two sets of supporting and pulling assemblies 2. Figure 3 , Figure 3 The schematic diagram of the manufacturing method of the electrode assembly provided in the present application is shown Figure 1 ,like Figure 3 As shown, the manufacturing method of the electrode assembly includes the following steps S101 to S104.

[0059] S101, connecting one end of the electrode assembly to the winding assembly.

[0060] In some embodiments, before winding the long strip electrode assembly by the electrode assembly manufacturing device, one end of the electrode assembly needs to be connected to the winding assembly, for example, by fixing one end of the electrode assembly to the electrode assembly by clamping, or by attaching one end of the electrode assembly to the surface of the winding assembly.

[0061] For example, refer to Figure 4 , Figure 4 A schematic diagram of the electrode assembly manufacturing device provided by the present application for winding a wound electrode assembly is shown. One end of the wound electrode assembly 5 can be inserted into the accommodating cavity 13 between the first winding member 11 and the second winding member 12 in the winding assembly 1, so that the winding assembly 1 drives the electrode assembly to rotate together when rotating, thereby completing the winding of the electrode assembly.

[0062] S102, controlling the winding assembly to rotate, and winding the electrode assembly to form a wound electrode assembly.

[0063] In some embodiments, after the electrode assembly and the winding assembly are connected, the winding assembly can be controlled to rotate in a preset rotation direction so that the long strip-shaped electrode assembly is wound around the winding assembly one circle at a time. For example, at the beginning of winding, the winding assembly can be rotated at a lower speed until the electrode assembly is wound around the winding assembly for at least one circle, at which time, there is sufficient friction between the stacked and wound electrode assemblies and between the winding assembly and the electrode assembly; then the winding assembly is controlled to rotate at a higher speed until the winding of one electrode assembly is completed, and a wound electrode assembly formed by stacking and winding multiple layers of electrode assemblies is obtained.

[0064] S103, controlling the winding assembly to withdraw from the wound electrode assembly, and placing the wound electrode assembly on a rolling device.

[0065] In some embodiments, after the winding of the wound electrode assembly is completed, a cylindrical wound electrode assembly is obtained, and the cylindrical wound electrode assembly can be moved to a rolling device of a rolling station to be shaped by the rolling device.

[0066] For example, the winding assembly can be first withdrawn from the cylindrical wound electrode assembly, and then the wound electrode assembly can be moved to the rolling device by a handling device. Alternatively, the wound electrode assembly can be moved to the rolling device by the winding assembly, and then the winding assembly can be withdrawn from the cylindrical wound electrode assembly.

[0067] Another example, such as Figure 2 As shown, the pressing device 3 includes a support platform 31 and a pressing member 32. The wound electrode assembly can be placed on the pressing device in step S1031.

[0068] S1031, placing the wound electrode assembly on a carrier, and controlling the pressing piece to move to a position corresponding to the wound electrode assembly.

[0069] In some embodiments, Figure 2 As shown, in the process of placing the wound electrode assembly on the pressing device, the wound electrode assembly 5 can be placed on the supporting platform 31 in the pressing device, and then the pressing piece 32 in the pressing device 3 is moved to the upper side of the wound electrode assembly 5 along the second direction E, so that the pressing piece 32 is in a position to flatten and shape the wound electrode assembly 5.

[0070] S104, controlling the two groups of supporting and pulling assemblies to at least partially move into the wound electrode assembly and to abut against two inner sides of the wound electrode assembly that are opposite to each other along the first direction.

[0071] In some embodiments, before or after the wound electrode assembly is placed on the support platform, a portion of the components in the two groups of supporting and pulling assemblies can be moved into the cylindrical wound electrode assembly.

[0072] For example, Figure 2 As shown, the two inner clamping members 21 in the two groups of supporting and pulling assemblies 2 can be moved to the interior of the wound electrode assembly 5, and the two inner clamping members 21 can be abutted against the two sides of the wound electrode assembly 5 along the first direction Y, that is, the two inner clamping members 21 are located on the same diameter in the wound electrode assembly 5 along the radial direction of the wound electrode assembly 5, and abut against the wound electrode assembly 5.

[0073] In another example, the first clamping member 221 and the second clamping member 222 may be moved to the outside of the wound electrode assembly 5, and the first clamping member 221 and the second clamping member 222 may abut against the outside of the wound electrode assembly 5. The first clamping member 221, the second clamping member 222 and the two inner clamping members 21 are arranged along the first direction Y.

[0074] S105, control the two groups of stretching assemblies to move in opposite directions at least twice in the first direction, and control the rolling device to apply force to the wound electrode assembly along the second direction to stretch and press the wound electrode assembly on at least one side; the second direction is perpendicular to the first direction.

[0075] In some embodiments, after the wound electrode assembly is placed on the rolling device, the cylindrical wound electrode assembly can be flattened and shaped through the coordinated cooperation of two sets of support and tension assemblies and the rolling device.

[0076] In some embodiments, after the wound electrode assembly is placed on the rolling device, the two outer clamping members 22 may be controlled to move to the outer circumferential sides of the wound electrode assembly and abut against the outer circumferential sides.

[0077] For example, Figure 2 As shown, after the wound electrode assembly 5 is placed on the carrier 31, the wound electrode assembly 5 needs to be fixed so as to apply a tensile force along the first direction Y to the cylindrical wound electrode assembly 5. The two outer clamping members 22 can be controlled to move from the standby position to the outer side of the wound electrode assembly 5 in the circumferential direction, and the two outer clamping members 22 are both in contact with the outer side of the wound electrode assembly 5 in the circumferential direction.

[0078] For example, along the first direction Y, the first clamping member 221 can be moved to the circumferential outer side of the wound electrode assembly 5 and to an inner clamping member 21 (such as Figure 2In this way, a portion of the wound electrode assembly 5 can be clamped and fixed by the first clamping member 221 and a corresponding inner clamping member 21. In addition, along the first direction Y, the second clamping member 222 can also be moved to the outer side of the circumference of the wound electrode assembly 5 and to the other inner clamping member 21 (such as Figure 2 The inner clamping piece 21 on the left in the figure is positioned at a position corresponding to the inner clamping piece 21 on the left, so that another part of the wound electrode assembly 5 is clamped and fixed by the second clamping piece 222 and the corresponding other inner clamping piece 21.

[0079] In this way, the pressing member is controlled to move to a position corresponding to the wound electrode assembly on the carrier, so that the pressing member can apply a force along the second direction E to the wound electrode assembly. In addition, the two outer clamping members are controlled to move to positions corresponding to the two inner clamping members, respectively, so that two points in the wound electrode assembly can be clamped and fixed along the first direction Y through two sets of supporting and stretching assemblies, so that a supporting and stretching shaping force can be applied to the wound electrode assembly along the first direction Y.

[0080] In some embodiments, after the wound electrode assembly is clamped and fixed on the carrier, Figure 2 As shown, the two inner clamping members 21 can be controlled to move away from each other along the first direction Y, and the first direction Y can be a direction parallel to or nearly parallel to the horizontal direction. The two inner clamping members 21 can then support and pull the cylindrical wound electrode assembly 5 along the first direction Y, so that the cylindrical wound shaping assembly is deformed into a flat wound electrode assembly 5. In this process, the outer clamping member 22 moves together with the inner clamping member 21.

[0081] For example, Figure 2 As shown, the rolling device 3 can also be controlled to generate movement along the second direction E to press the cylindrical wound electrode assembly 5 or the flat wound electrode assembly 5, so that the wound electrode assembly 5 is deformed to be flatter. The second direction E can be a direction parallel or nearly parallel to the vertical direction, and the first direction Y and the second direction E are perpendicular or nearly perpendicular to each other.

[0082] It should be noted that, while the two inner clamps 21 are controlled to stretch the wound electrode assembly 5, the pressing device 3 is controlled to press the wound electrode assembly 5. It is also possible to control the two inner clamps 21 to stretch the wound electrode assembly 5 for a certain distance, and then control the pressing device 3 to press the wound electrode assembly 5 after stretching, so as to complete a stretching and shaping of the wound electrode assembly 5. In this way, after the wound electrode assembly 5 is stretched and shaped multiple times, the two parts extending along the first direction Y in the cylindrical wound electrode assembly 5 can be completely fitted together to obtain a wound electrode assembly 5 that is approximately a rectangular parallelepiped. That is, the stretching and shaping of the wound electrode assembly 5 is completed.

[0083] The manufacturing method of the electrode assembly provided in the embodiment of the present application connects one end of the electrode assembly to the winding assembly, so that the winding assembly drives the electrode assembly to be wound during the rotation process, so as to complete the winding of the long strip electrode assembly. And the obtained wound electrode assembly is placed on a rolling device, and the cylindrical wound electrode assembly can be flattened and shaped by the rolling device. At the same time, in the process of flattening and shaping the cylindrical wound electrode assembly by the rolling device, two groups of stretching assemblies are also controlled to stretch the wound electrode assembly from the inside, so that the inner circle of the wound electrode assembly can be stretched flat, and a force along the first direction can be applied to the bent part of the flattened wound electrode assembly, which is conducive to making the various layers of the bent part of the wound electrode assembly fit closely, thereby reducing the risk of wrinkles or gaps in the wound electrode assembly obtained after flattening and shaping, which is conducive to improving the quality of the wound electrode assembly obtained, and then the service life of the battery using the wound electrode assembly can be improved.

[0084] Reference Figure 5 , Figure 5 The schematic diagram of the manufacturing method of the electrode assembly provided in the present application is shown Figure 2 .based on Figure 3 , Figure 3 Step S105 in the above example can be implemented by step S1051 as follows: Figure 5 Provide explanation.

[0085] S1051, after controlling the two groups of supporting and pulling assemblies to move away from each other in the first direction each time, controlling the pressing device to apply force to the wound electrode assembly along the second direction at least once.

[0086] In some embodiments, in the process of controlling the stretching assembly to stretch the wound electrode assembly, and pressing the wound electrode assembly by the rolling device, the two sets of stretching assemblies can first move in the opposite direction along the first direction to complete the stretching of the wound electrode assembly. After completing the stretching of the wound electrode assembly once, the rolling device is used to press the wound electrode assembly in the second direction. In this way, the wound electrode assembly can be stretched and pressed once. In this way, the wound electrode assembly can be stretched and pressed at least twice until the shaping process of the wound electrode assembly is completed.

[0087] In the above embodiment, after the wound electrode assembly is stretched once by the stretching assembly, the wound electrode assembly is pressed at least once by the pressing device, so that the electrode assembly in the inner layer of the wound electrode assembly can be stretched multiple times, which is beneficial to reduce the occurrence of wrinkles in the wound electrode assembly.

[0088] Reference Figure 6 , Figure 6 The schematic diagram of the manufacturing method of the electrode assembly provided in the present application is shown Figure 3 The rolling device includes a supporting platform and a pressing member which are arranged opposite to each other, and the wound electrode assembly is carried on the supporting platform. Figure 5 , Figure 5 Step S1041 in the above example can be implemented by steps S301 to S303 as follows: Figure 6 Provide explanation.

[0089] S301. Determine the opening distance of two groups of support and tension assemblies based on the length of the winding start section in the wound electrode assembly; the winding start section is a section of the electrode assembly located at the innermost layer in the wound electrode assembly.

[0090] In some embodiments, after the cylindrical wound electrode assembly is placed on a rolling device and the cylindrical wound electrode assembly is clamped and fixed, the cylindrical wound electrode assembly may be stretched first.

[0091] For example, refer to Figure 7 and Figure 8 , Figure 7 A schematic diagram of the process of forming a wound electrode assembly provided in this application, Figure 8 The schematic diagram of the structure of the wound electrode assembly obtained after the stretching and pressing shaping provided in the present application. The stretching distance of the cylindrical wound electrode can be determined according to the winding starting section length L1 of the winding starting section 51 in the wound electrode assembly 5. The wound electrode assembly 5 is formed by winding the same electrode assembly through multiple turns, and the winding starting section 51 is a section of the electrode assembly located in the innermost layer of the wound electrode assembly 5, that is, the winding starting section 51 includes the innermost circle of the electrode assembly in the wound electrode assembly 5. The winding starting section length L1 of the winding starting section 51 is the circumference of the innermost circle of the electrode assembly in the wound electrode assembly 5.

[0092] In another example, after the length L1 of the winding start section is determined, the opening distance of the two groups of stretching assemblies 2 moving along the first direction Y during the stretching of the cylindrical wound electrode assembly 5 can be determined according to the length L1 of the winding start section. For example, the opening distance B of the two groups of stretching assemblies 2 can be determined according to formula (1), and the opening distance B is the distance after the two groups of stretching assemblies 2 complete the stretching of the cylindrical wound electrode assembly 5.

[0093] Formula (1);

[0094] Where a represents the adjustment coefficient.

[0095] For example, a may be set to a parameter ranging from 1 mm to 4 mm, such as a value of 2 mm.

[0096] S302: Based on the opening distance, control the clamping members corresponding to the two groups of supporting and pulling assemblies to synchronously generate reverse movements along the first direction to support and pull the wound electrode assembly.

[0097] In some embodiments, after the opening distance is determined, the two groups of stretching assemblies can be controlled to move along a first direction to stretch the cylindrical wound electrode assembly.

[0098] For example, Figure 7 As shown in ①, the support and tension assembly 2 on the left side of the figure can be controlled to remain stationary in the first direction Y, while the support and tension assembly 2 on the right side of the figure can be controlled to move rightward along the first direction Y until the distance between the two groups of support and tension assemblies 2 is the opening distance. Then, the cylindrical wound electrode assembly 5 can be stretched once to deform the cylindrical wound electrode assembly 5 into Figure 7 The flat wound electrode assembly 5 shown in ①.

[0099] S303, controlling the pressing member to move along the second direction toward the direction approaching the wound electrode assembly until the pressing member abuts against the wound electrode assembly.

[0100] In some embodiments, after the cylindrical wound electrode assembly is stretched once by the stretching assembly, the flat wound electrode assembly can be pressed and shaped by the pressing member and the supporting platform.

[0101] For example, Figure 7 As shown in ②, the pressing member 32 can be controlled to move toward the wound electrode assembly 5 along the second direction E until the pressing member 32 abuts against the circumferential side surface (the upper surface shown in the figure) of the wound electrode assembly 5. In this way, the wound electrode assembly 5 that has been stretched and deformed into a flat shape is clamped and fixed by the pressing member 32 and the supporting platform 31 in the second direction E, so that the wound electrode assembly 5 can be kept in the state after being stretched.

[0102] In the above embodiment, since the two groups of stretching assemblies are controlled to move in opposite directions along the first direction according to the opening distance of the two groups of stretching assemblies, the cylindrical wound electrode assembly can be stretched into a flat shape along the first direction by the two groups of stretching assemblies to complete the one-time shaping of the wound electrode assembly. Moreover, in the process of the two groups of stretching assemblies stretching the wound electrode assembly, since the force is applied from the inside of the wound electrode assembly to the outside of the wound electrode assembly, the various layers of the internal structure of the wound electrode assembly can be stretched flat, which is conducive to reducing the wrinkles and gaps caused by the force on various parts of the wound electrode assembly.

[0103] Reference Fig. 9 , Fig. 9 The schematic diagram of the manufacturing method of the electrode assembly provided in the present application is shown Figure 4Each group of support and tension components includes an inner clamping member and an outer clamping member, wherein the inner clamping member abuts against the inner side of the wound electrode component, and the outer clamping member abuts against the outer side of the wound electrode component. Figure 5 , Figure 5 Step S1051 in the above example can also be implemented by the following steps S401 to S404. Fig. 9 Provide explanation.

[0104] S401, controlling the first clamping member to move along a first direction away from the wound electrode assembly; the first clamping member is an outer clamping member of the two outer clamping members that is close to the free end of the winding starting section.

[0105] In some embodiments, after the winding electrode assembly is stretched and shaped once, the press can be controlled to flatten and shape the winding electrode assembly. Since the outer clamp and the inner clamp in each group of the stretching assembly clamp and fix a part of the winding electrode assembly, the outer clamp located on the outer side of the winding electrode assembly can be controlled to move away from the winding electrode assembly, so that there is a gap between the outer clamp and the winding electrode assembly. In this way, the outer clamp restricts the deformation of the winding electrode assembly during the process of the press flattening the winding electrode assembly.

[0106] For example, Figure 7 neutralize Figure 8 As shown, the first clamping member 221 can be controlled to move in the first direction Y away from the wound electrode assembly 5 to release the clamping and fixing of the wound electrode assembly 5. The first clamping member 221 is an outer clamping member 22 close to the free end 511 of the winding start section 51 in the wound electrode assembly 5. In this way, the clamping, fixing and restriction of the free end 511 of the winding start section 51 in the wound electrode assembly 5 can be released.

[0107] S402, controlling the pressing component to move along the second direction toward the wound electrode assembly by a first preset distance.

[0108] In some embodiments, after the first clamping member is released from clamping the wound electrode assembly, the pressing member can be controlled to flatten and shape the wound electrode assembly.

[0109] For example, the pressing member can be controlled to flatten and reshape the wound electrode assembly along the second direction according to the first preset distance. For example, the first preset distance can be a distance of 1 mm to 3 mm, such as controlling the pressing member to move 1 mm in the direction close to the wound electrode assembly along the second direction. Figure 7 As shown in ③, the wound electrode assembly 5 is extended to the right, so that a gap is generated between the inner clamping member 21 adjacent to the first clamping member 221 and the wound electrode assembly 5 .

[0110] S403, controlling the inner clamping member to move along the second direction toward the bearing platform by a second preset distance.

[0111] In some embodiments, Figure 7 As shown in ③, after the press-fitting member is controlled to flatten and shape the wound electrode assembly once, the symmetry line S of the wound electrode assembly 5 is displaced, and the two inner clamping members 21 can be controlled to move along the second direction so that the two inner clamping members 21 move to the symmetry line S of the wound electrode assembly 5. In this way, when the wound electrode assembly 5 is stretched again by the inner clamping member 21, the inner clamping member 21 can be brought into contact with the inner corner of the wound electrode assembly 5, which is conducive to reducing the relative slippage between the inner clamping member 21 and the electrode assembly near the inner corner of the wound electrode assembly 5.

[0112] S404, controlling the two inner clamping members to generate reverse movement along the first direction with a preset stretching distance.

[0113] In some embodiments, after controlling the pressing member to flatten and shape the wound electrode assembly once, the two inner clamping members can be controlled to move in opposite directions along the first direction to stretch and shape the wound electrode assembly again.

[0114] For example, Figure 7 As shown in ④, the inner clamping member 21 close to the first clamping member 221 can be controlled to move in a direction away from the other inner clamping member 21 to perform a second stretching and shaping of the wound electrode assembly 5. For example, the inner clamping member 21 can be controlled to move a preset stretching distance along the first direction Y, and the preset stretching distance can be a distance of 0.2mm to 3mm. For example, the inner clamping member 21 is controlled to move 1mm along the first direction Y again. And after the inner clamping member 21 moves the preset stretching distance, the position of the inner clamping member 21 after the second stretching can be controlled to maintain a preset time, such as maintaining a time of 0.2s to 3s, so that the wound electrode assembly 5 has enough time to produce corresponding deformation after being subjected to the stretching force.

[0115] In the above embodiment, since the pressing member is controlled to move the wound electrode assembly along the second direction, the wound electrode assembly can be flattened and shaped by the pressing member and the carrier, which is conducive to making the layers of the wound electrode assembly fit more closely. And the inner clamping member is controlled to move along the first direction to produce a preset stretching distance, and the layers on the inner side of the wound electrode assembly can be stretched again by the inner clamping member, so that the bent part of the wound electrode assembly after being flattened can be stretched flat, which is conducive to reducing wrinkles or gaps in the wound electrode assembly.

[0116] Reference Fig.10 , Fig.10 The schematic diagram of the manufacturing method of the electrode assembly provided in the present application is shown Figure 5 .based on Figure 5 , Figure 5 Step S1051 in the above example can also be implemented by the following steps S501 to S504. Fig.10 Provide explanation.

[0117] S501, controlling the pressing component to move along the second direction toward the direction of the wound electrode assembly by a third preset distance and maintaining the movement for a preset time.

[0118] In some embodiments, after the wound electrode assembly is stretched and shaped for the second time, the wound electrode assembly may be flattened and shaped again to complete another stretching and pressing shaping of the wound electrode assembly.

[0119] For example, Figure 7 As shown in ⑤, the pressing member 32 can be controlled to move again in the second direction E toward the direction close to the wound electrode assembly 5, so as to apply a pressing force in the second direction E to the wound electrode assembly 5 again. For example, the pressing member 32 can be controlled to move a third preset distance in the second direction E. The third preset distance can be 0.5 mm to 4 mm, for example, the third preset distance can be 2 mm.

[0120] In another example, after the pressing member 32 is controlled to apply the pressing force to the wound electrode assembly 5 again, the pressing member 32 can be kept at the position where the wound electrode assembly 5 is flattened for a preset time. For example, the preset time can be 0.5s to 3s. In this way, the wound electrode assembly 5 can have sufficient time to produce corresponding deformation under the action of the pressing force.

[0121] S502, controlling the second clamping member to move along the first direction away from the wound electrode assembly; the second clamping member is the clamping member at the free end of the two clamping members away from the winding starting section.

[0122] In some embodiments, Figure 7 As shown in ⑤, after the wound electrode assembly 5 is flattened and reshaped again, the second clamping member 222 can be controlled to separate from the wound electrode assembly 5, that is, the second clamping member 222 can be controlled to move away from the wound electrode assembly 5 along the first direction Y, so that there is a large gap between the second clamping member 222 and the wound electrode assembly 5. At this time, there is a large gap between the first clamping member 221 and the second clamping member 222 and the wound electrode assembly 5.

[0123] S503, controlling the two inner clamps to withdraw from the wound electrode assembly.

[0124] In some embodiments, the two portions of the wound electrode assembly extending along the first direction are not completely in contact with each other. Figure 7As shown in ⑥, the two inner clamping members 21 can be moved in the direction of approaching each other along the first direction Y by a preset retraction distance, such as moving the two inner clamping members 21 in the direction of approaching each other by 2mm to 6mm, so that there is a sufficient gap between the inner clamping members 21 and the inner wall of the wound electrode assembly 5 in the first direction Y. Then the two inner clamping members 21 are controlled to withdraw from the wound electrode assembly 5, such as withdrawing from the inner clamping members 21 in a direction perpendicular to the paper surface. At this time, the two inner clamping members 21 and the two outer clamping members 22 no longer exert a force on the wound electrode assembly 5, and no longer restrict the movement of the wound electrode assembly 5.

[0125] S504, controlling the pressing member to move along the second direction toward the direction approaching the wound electrode assembly until the winding start section is in contact with the adjacent electrode assembly.

[0126] In some embodiments, Figure 7 As shown in ⑦, the pressing member 32 can be controlled to flatten and reshape the wound electrode assembly 5 again along the second direction E, that is, the pressing member 32 is controlled to move along the second direction E toward the direction close to the wound electrode assembly 5 until the two parts of the wound electrode assembly 5 extending along the first direction Y are completely attached, that is, the winding start section 51 is completely attached to the adjacent electrode assembly. In this way, the wound electrode assembly 5 is completely flattened to complete the flattening and shaping of the wound electrode assembly 5, and a wound electrode assembly 5 approximately in the shape of a rectangular parallelepiped is obtained.

[0127] For example, in the process of controlling the pressing member 32 to completely flatten the wound electrode assembly 5, the pressure applied by the pressing member 32 to the wound electrode assembly 5 can be set to 70% to 95% of the pressure that can be generated by the rolling device 3. In this way, the extrusion deformation of the inner ring of the flattened wound electrode assembly 5 due to the extrusion force can be effectively reduced, so that the obtained wound electrode assembly 5 in a shape similar to a rectangular parallelepiped has a better flattening and shaping effect.

[0128] In the above embodiment, since the pressing part is controlled to flatten and shape the wound electrode assembly again by a smaller distance before the pressing part is controlled to completely flatten the wound electrode assembly, the extrusion deformation and extrusion stress generated in the inner circle of the wound electrode assembly can be effectively reduced, thereby reducing the tiny wrinkles and gaps generated between the various layer structures in the wound electrode assembly, which is beneficial to improving the quality of the wound electrode assembly.

[0129] Reference Fig.11 , Fig.11 The schematic diagram of the manufacturing method of the electrode assembly provided in the present application is shown Figure 6 .based on Figure 3 , Figure 3 Step S105 in the above example can be implemented by steps S601 to S602 as follows: Fig.11 Provide explanation.

[0130] S601, controlling the rolling device to apply force to the wound electrode assembly along a second direction.

[0131] In some embodiments, Figure 2 As shown, the rolling device 3 can be controlled to continuously apply force to the wound electrode assembly 5 along the second direction E to flatten the cylindrical wound electrode assembly 5 until the two parts of the wound electrode assembly 5 extending along the first direction Y are completely fitted together.

[0132] S602, controlling the two groups of supporting and pulling assemblies to produce reverse movement along the first direction, while controlling the two groups of supporting and pulling assemblies to produce movement along the second direction, so that the two groups of supporting and pulling assemblies remain on the symmetry line of the wound electrode assembly; the symmetry line is parallel to the first direction.

[0133] In some embodiments, Figure 2 As shown, while the wound electrode assembly 5 is flattened and shaped by step S601, the two groups of stretching assemblies 2 can be controlled to move away from each other along the first direction Y, so that the two groups of stretching assemblies 2 press the first direction Y to apply a reverse force to the inner side of the wound electrode assembly 5, thereby stretching the inner layer of the wound electrode assembly 5. And while controlling the wound electrode assembly 5 to move in the opposite direction along the first direction Y, according to the speed of the symmetry line S of the wound electrode assembly 5 moving along the second direction E, the two groups of stretching assemblies 2 are synchronously controlled to move along the second direction E. In this way, the two groups of stretching assemblies 2 are basically kept on the symmetry line S of the wound electrode assembly 5. This is conducive to reducing the relative slip between the stretching assemblies 2 and the wound electrode assembly 5.

[0134] Exemplarily, before the wound electrode assembly 5 is completely flattened, the two groups of support and tension assemblies 2 can be withdrawn from the wound electrode assembly 5. For example, when the distance between the inner layers of the wound electrode assembly 5 along the second direction E is the same as the thickness of the support and tension assemblies 2 along the second direction E, the two groups of support and tension assemblies 2 can be controlled to withdraw from the wound electrode assembly 5.

[0135] In the above embodiment, since the two groups of stretching assemblies are controlled to move in the first direction while the pressing device is controlled to flatten and reshape the wound electrode assembly, the stretching assemblies can be used to stretch the inner circle of the flattened wound electrode assembly, which is conducive to keeping the inner circle of the wound electrode assembly flat, and can keep the layers of the structure at the corners of the wound electrode assembly tightly fitted under the force applied by the stretching assemblies, thereby reducing the risk of wrinkles or gaps in the wound electrode assembly, which is conducive to improving the quality of the wound electrode assembly.

[0136] Reference Fig.12 , Fig.12The schematic diagram of the manufacturing method of the electrode assembly provided in the present application is shown Figure 7 The winding assembly includes a first winding member and a second winding member, and a receiving cavity extending in the radial direction of the winding assembly is formed between the first winding member and the second winding member. The first winding member and the second winding member each have a receiving groove on their circumferential surfaces, and the two receiving grooves are located on the same diameter of the winding assembly. Each group of supporting and pulling assemblies includes an inner clamping member located in the wound electrode assembly, and the two inner clamping members are respectively accommodated in the two receiving grooves. Based on Figure 3 , Figure 3 Step S101 in the above example can be implemented by steps S701 to S702 as follows: Fig.12 Provide explanation.

[0137] S701. Based on the length of the winding start section in the wound electrode assembly, adjust the structural form of the wound assembly and the two inner clamps to a winding posture; the winding start section is a section of the electrode assembly located at the innermost layer in the wound electrode assembly.

[0138] In some embodiments, before the long strip electrode assembly is wound by the winding assembly and the inner clamp, the relative positions of the first winding member and the second winding member in the winding assembly need to be adjusted according to the length of the winding starting section of the wound electrode assembly of different types or models. Figure 1 As shown, the accommodation distance ΔL of the accommodation cavity 13 between the first winding member 11 and the second winding member 12 can be adjusted. At the same time, the positions of the two inner clamping members 21 in the accommodation cavity 13 can be adjusted, for example, the positions of the inner clamping members 21 in the accommodation groove 14 relative to the winding assembly 1 along the circumferential direction Z of the winding assembly 1 are changed. In this way, the structural form of the winding assembly 1 and the two inner clamping members 21 can achieve the desired winding posture.

[0139] In the wound posture, the circumferential length of the wound assembly 1 and the like match the circumference of the inner ring portion of the wound electrode assembly 5, thereby obtaining a wound electrode assembly 5 whose size meets the processing requirements.

[0140] S702, placing at least a portion of the winding start section in a receiving cavity in a winding posture to connect the electrode assembly to the winding assembly.

[0141] In some embodiments, after the winding assembly and the inner clamp are adjusted, one end of the electrode assembly can be connected to the winding assembly, so that the winding assembly can be controlled to rotate to achieve the winding process of the electrode assembly.

[0142] For example, Figure 4As shown, the winding start section 51 in the wound electrode assembly 5 can be inserted into the accommodating cavity 13 of the wound assembly 1, so as to increase the friction between the wound electrode assembly 5 and the wound assembly 1. For example, the length of the winding start section 51 inserted into the accommodating cavity 13 can be determined according to the length of the winding start section 51.

[0143] In the above embodiment, since the structural forms of the winding assembly and the two inner clamping members are adjusted according to the length of the winding starting section, the circumference of the winding assembly can be matched with the length of the winding starting section of the wound electrode assembly, thereby improving the dimensional accuracy of the wound electrode assembly formed by winding, and further improving the processing quality of the wound electrode assembly.

[0144] Reference Fig.13 , Fig.13 The schematic diagram of the manufacturing method of the electrode assembly provided in the present application is shown Figure 8 .based on Fig.12 , Fig.12 Step S701 in the above example can be implemented by step S7011, which is combined with Fig.13 Provide explanation.

[0145] S7011. Based on the length of the winding start section, adjust the accommodation distance between the first winding member and the second winding member; the direction of the accommodation distance is perpendicular to the extension direction of the accommodation cavity.

[0146] In some embodiments, the circumference of the winding assembly along the circumferential direction can be adjusted to achieve winding electrode assemblies of different thicknesses.

[0147] Exemplarily, a thickening layer can be pasted on the circumferential side of the first winding member and the second winding member to change the circumference of the winding assembly. For example, a polytetrafluoroethylene sheet can be pasted on the circumferential side of the first winding member and the second winding member.

[0148] Another example, such as Figure 1 and Figure 4 As shown, the first winding member 11 and the second winding member 12 can be moved closer to or farther from each other by adjusting the accommodation distance ΔL between the first winding member 11 and the second winding member 12, that is, by adjusting the width of the accommodation cavity 13 between the first winding member 11 and the second winding member 12, so as to adjust the circumference of the winding assembly 1 along the circumferential direction Z. The accommodation distance ΔL is perpendicular or nearly perpendicular to the extension direction of the accommodation cavity 13. In the process of adjusting the accommodation distance ΔL, the size of the accommodation distance ΔL can be determined according to formula (2).

[0149] Formula (2);

[0150] In the formula, D represents the diameter of the first winding member 11, and b represents the adjustment coefficient.

[0151] For example, b may be set to a parameter ranging from 1 mm to 4 mm, such as a value of b of 2 mm.

[0152] In the above embodiment, since the theoretical accommodation distance between the first winding member and the second winding member is determined according to the length of the starting section of the winding, and the actual accommodation distance between the first winding member and the second winding member is adjusted based on the determined accommodation distance, the circumference of the winding assembly can be made nearly consistent with the length of the starting section of the wound electrode assembly, thereby improving the dimensional accuracy of the wound electrode assembly formed by winding the winding assembly.

[0153] Reference Fig.14 , Fig.14 The schematic diagram of the manufacturing method of the electrode assembly provided in the present application is shown Figure 9 .based on Fig.12 , Fig.12 Step S701 in can also be implemented by the following step S7012: Fig.12 Step S702 in the embodiment can be implemented by the following step S7021. Fig.14 Provide explanation.

[0154] S7012. Based on the length of the winding start section, adjust the phase angle between the inner clamp and the accommodating section in the winding start section located in the accommodating cavity; the phase angle is the angle between the inner clamp and the accommodating section along the circumferential direction of the winding assembly.

[0155] In some embodiments, the length of the winding start section connected to the winding assembly through the inner clamping member can be adjusted by adjusting the position of the inner clamping member relative to the winding assembly along the circumferential direction Z of the winding assembly.

[0156] For example, Figure 4 As shown in FIG. 1 , when the accommodation distance ΔL between the first winding member 11 and the second winding member 12 is fixed, the angle between the two inner clamping members 21 and the accommodation section 52 in the winding start section 51 located in the accommodation cavity 13 can be adjusted, that is, the phase angle θ between the inner clamping members 21 and the accommodation section 52 can be adjusted. In this way, along the circumferential direction Z of the winding assembly 1, the length of the portion extending from the edge of the accommodation cavity 13 to the inner clamping members 21 in the winding start section 51 can be changed. That is, as shown in FIG. Figure 4 As shown in the figure, the length of the portion of the winding starting section 51 within the phase angle θ that is in contact with the circumferential side of the first winding member 11 can be changed, and the length of the portion of the winding starting section 51 within the phase angle θ that is in contact with the circumferential side of the second winding member 12 can be changed, thereby changing the winding starting section length L1 of the winding starting section 51.

[0157] As another example, in the process of determining the phase angle θ, the magnitude of the phase angle θ may be determined according to formula (3).

[0158] Formula (3);

[0159] In the formula, D represents the diameter of the first winding member 11, R represents the length of the accommodating section 52, and c is an adjustment parameter.

[0160] For example, c may be set to a parameter ranging from 1 mm to 4 mm, such as a value of c of 2 mm.

[0161] S7021. Pass the winding starting section into the accommodating cavity from the first end of the accommodating cavity, and extend until at least a portion of the winding starting section passes through the inner clamping piece in the first accommodating groove; the first accommodating groove is one of the two accommodating grooves close to the second end of the accommodating cavity, and the first end and the second end are respectively the two ends of the accommodating cavity along the radial direction of the wound electrode assembly.

[0162] In some embodiments, after the phase angle between the inner clamping member and the accommodating section is determined and adjusted, the winding start section can be connected to the winding assembly.

[0163] For example, Figure 4 As shown in FIG. 5 , the free end 511 of the winding start section 51 can be Figure 4 The first end on the left side of the middle accommodating cavity 13 is inserted into the accommodating cavity 13, and the free end 511 of the winding start section 51 is passed through the second end on the right side of the accommodating cavity 13. The free end 511 of the winding start section 51 is then pulled to pass through the inner clamping member 21 in the first accommodating groove 14, and the free end 511 can be connected with the inner clamping member 21 in the first accommodating groove 14, such as being fitted and abutted. Figure 4 The receiving groove 14 on the first winding member 11 shown in FIG. Figure 4 In this way, after the winding of the wound electrode assembly 5 is completed, the cylindrical wound electrode assembly 5 is stretched into a flat wound electrode assembly 5 by the two inner clamping members 21, and the length of the winding start section 51 between the two inner clamping members 21 is consistent with or nearly consistent with the desired winding start section length L1.

[0164] In the above embodiment, since the phase angle between the inner clamping member and the accommodating section is adjusted according to the length of the winding start section, the path length between the two inner clamping members can be adjusted quickly and conveniently. In addition, the phase angle between the inner clamping member and the accommodating section is easier to control and accurately adjust, so that the actual winding start section length of the inner clamping member obtained can be consistent or nearly consistent with the desired winding start section length, which is beneficial to control the dimensional accuracy of the winding process of the wound electrode assembly.

[0165] An embodiment of the present application also provides a battery cell, which includes a shell and an electrode assembly, and the electrode assembly includes: a positive electrode, a negative electrode and an isolation member, and the isolation member is located between the positive electrode and the negative electrode; the positive electrode, the isolation member and the negative electrode are processed into an electrode assembly by the manufacturing method of the electrode assembly provided in any one of the above embodiments.

[0166] In some embodiments, an electrode assembly including a positive electrode, a separator, and a negative electrode may be wound by the electrode assembly manufacturing method provided in any of the above embodiments to obtain a wound electrode assembly in an approximately rectangular parallelepiped shape.

[0167] The battery cell provided in the embodiments of the present application includes an electrode assembly obtained by winding and shaping through the manufacturing method of the electrode assembly provided in any of the above embodiments. Therefore, the risk of wrinkles or gaps forming in the electrode assembly obtained after flattening and shaping can be reduced, which is beneficial to improving the quality of the obtained electrode assembly and further improving the service life of the battery cell.

[0168] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application is described in detail with reference to the above embodiments, a person skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way.

Claims

1. A method for manufacturing an electrode assembly, applied to an electrode assembly manufacturing device, the electrode assembly manufacturing device comprising a winding assembly, a rolling device and two sets of stretching assemblies, the winding assembly comprising a first winding member and a second winding member, a receiving cavity extending in the radial direction of the winding assembly is formed between the first winding member and the second winding member, the first winding member and the second winding member respectively have a receiving groove on the circumferential surface, the two receiving grooves are located on the same diameter of the winding assembly, the stretching assembly comprises an inner clamping member, characterized in that, The manufacturing method comprises: Controlling the two inner clamping members to move into the two containing grooves respectively; Based on the length of the winding start section in the wound electrode assembly, adjusting the structural form of the wound assembly and the two inner clamping members to a winding posture; the winding start section is a section of the electrode assembly located at the innermost layer of the wound electrode assembly; placing at least a portion of the winding start section in the receiving cavity in the winding posture to connect the electrode assembly to the winding assembly; Controlling the winding assembly to rotate, and winding the electrode assembly to form the wound electrode assembly; Controlling the winding assembly to withdraw from the wound electrode assembly and placing the wound electrode assembly on a rolling device; The two inner clamping members are controlled to move in opposite directions at least twice in a first direction, and the pressing device is controlled to apply a force to the wound electrode assembly in a second direction to stretch and shape the wound electrode assembly at least once; the second direction is perpendicular to the first direction.

2. The manufacturing method according to claim 1, characterized in that: The controlling the two inner clamping members to move in opposite directions at least twice in the first direction, and controlling the rolling device to apply a force to the wound electrode assembly in the second direction, comprises: After controlling the two inner clamping members to move away from each other in the first direction each time, controlling the rolling device to apply a force to the wound electrode assembly along the second direction at least once.

3. The manufacturing method according to claim 2, characterized in that: The pressing device comprises a supporting platform and a pressing member which are arranged opposite to each other, and the wound electrode assembly is carried on the supporting platform; after controlling the two inner clamping members to move away from each other in the first direction each time, controlling the pressing device to apply a force to the wound electrode assembly along the second direction comprises: Based on the length of the winding start section in the wound electrode assembly, the opening distance of the two inner clamping members is determined; the winding start section is a section of the electrode assembly located in the innermost layer of the wound electrode assembly; the opening distance is equal to the difference between one half of the length of the winding start section and the adjustment coefficient; Based on the opening distance, controlling the two inner clamping members to move away from each other along the first direction to support and stretch the wound electrode assembly; The pressing member is controlled to move along the second direction toward the direction approaching the wound electrode assembly until the pressing member abuts against the wound electrode assembly.

4. The manufacturing method according to claim 3, characterized in that: Each group of the support and tension assemblies further includes an outer clamping member, the inner clamping member abuts against the inner side of the wound electrode assembly, and the outer clamping member abuts against the outer side of the wound electrode assembly; after the step of controlling the pressing member to move along the second direction toward the direction close to the wound electrode assembly until the pressing member abuts against the wound electrode assembly, the manufacturing method further includes: Controlling the first clamping member to move along the first direction away from the wound electrode assembly; the first clamping member is an outer clamping member of the two outer clamping members close to the free end of the winding starting section; Controlling the pressing member to move a first preset distance along the second direction toward the direction approaching the wound electrode assembly; Controlling the inner clamping member to move a second preset distance along the second direction toward the direction close to the bearing platform; The two inner clamping members are controlled to generate reverse movement of a preset stretching distance along the first direction.

5. The manufacturing method according to claim 4, characterized in that: After the step of controlling the two inner clamping members to generate reverse movement along the first direction with a preset stretching distance, the manufacturing method further comprises: Controlling the pressing member to move along the second direction toward the direction close to the wound electrode assembly by a third preset distance and maintaining the movement for a preset time; Controlling the second clamping member to move along the first direction in a direction away from the wound electrode assembly; the second clamping member is the clamping member of the two clamping members that is away from the free end of the winding starting section; Controlling the two inner clamps to withdraw from the wound electrode assembly; The pressing member is controlled to move along the second direction toward the direction approaching the wound electrode assembly until the winding start section is in contact with the adjacent electrode assembly.

6. The manufacturing method according to claim 1, characterized in that: The controlling the two inner clamping members to move in opposite directions at least twice in the first direction, and controlling the rolling device to apply a force to the wound electrode assembly in the second direction, comprises: Controlling the pressing device to apply a force to the wound electrode assembly along the second direction; While controlling the two inner clamping members to produce reverse movement along the first direction, the two groups of the supporting and pulling assemblies are controlled to produce movement along the second direction so that the two groups of the supporting and pulling assemblies remain on the symmetry line of the wound electrode assembly; the symmetry line is parallel to the first direction.

7. The manufacturing method according to claim 1, characterized in that: The step of adjusting the structural form of the winding assembly and the two inner clamping members to a winding posture based on the length of the winding starting section in the wound electrode assembly comprises: Based on the length of the winding start section, the accommodation distance between the first winding member and the second winding member is adjusted; the direction of the accommodation distance satisfies a perpendicular relationship with the extension direction of the accommodation cavity.

8. The manufacturing method according to claim 1, characterized in that: The step of adjusting the structural form of the winding assembly and the two inner clamping members to a winding posture based on the length of the winding starting section in the wound electrode assembly further includes: Based on the length of the winding start section, the phase angle between the inner clamp and the accommodating section in the winding start section located in the accommodating cavity is adjusted; the phase angle is the angle between the inner clamp and the accommodating section along the circumferential direction of the winding assembly.

9. The method for manufacturing an electrode assembly according to claim 8, characterized in that: Placing at least a portion of the winding start section in the accommodating cavity in the winding posture comprises: The winding starting section is passed through the accommodating cavity from the first end of the accommodating cavity and extended until at least a portion of the winding starting section passes through the inner clamping member in the first accommodating groove; the first accommodating groove is one of the two accommodating grooves close to the second end of the accommodating cavity, and the first end and the second end are respectively the two ends of the accommodating cavity along the radial direction of the winding assembly.

10. A battery cell, characterized in that: It comprises an electrode assembly manufactured by the manufacturing method according to any one of claims 1 to 9.

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