CN116613369B

CN116613369B - Electrode assembly and cell head winding method

Info

Publication number: CN116613369B
Application number: CN202310901599.5A
Authority: CN
Inventors: 刘少杰; 严坤
Original assignee: Shenzhen Haichen Energy Storage Control Technology Co ltd; Xiamen Hithium Energy Storage Technology Co Ltd
Current assignee: Shenzhen Haichen Energy Storage Control Technology Co ltd; Xiamen Hithium Energy Storage Technology Co Ltd
Priority date: 2023-07-21
Filing date: 2023-07-21
Publication date: 2024-03-01
Anticipated expiration: 2043-07-21
Also published as: CN116613369A

Abstract

Electrode subassembly and electric core head coiling method relates to electric core structure technical field, includes: the first diaphragm, the first pole piece, the second diaphragm and the second pole piece are in a winding structure and are sequentially stacked in the same circle; the first diaphragm, the second diaphragm and the first pole piece positioned between the first diaphragm and the second diaphragm are flush at the head end in the core of the electrode assembly, the first pole piece is an anode piece, the second pole piece is a cathode piece, or the first pole piece is a cathode piece, and the second pole piece is an anode piece. According to the method, the first diaphragm, the second diaphragm and the first pole piece between the first diaphragm and the second diaphragm are in a flush state and enter the winding mechanism, so that the pole piece and the diaphragm in the battery cell can be guaranteed to be in a continuous tension state in the whole winding process, the design that the head pole piece and the diaphragm are continuously wound is finally achieved, and the design that the anode area in the battery cell design is larger than that of the cathode can be met.

Description

Electrode assembly and cell head winding method

Technical Field

The application relates to the technical field of battery cell structures, in particular to an electrode assembly and a battery cell head winding method.

Background

At present, the battery cell structure mainly comprises four layers of a diaphragm, an anode pole piece, a diaphragm and a cathode pole piece. In the winding process of the battery cell, a segmented cutting process is generally adopted at the tail-end part of the single battery cell, the cutting step can be divided into three steps, and at the winding tail-end position, a cathode pole piece is cut firstly, an anode pole piece is cut secondly, and finally a diaphragm is cut.

The discontinuous winding mode of the pole piece caused by the sectional cutting can lead to no tension holding of the pole piece at the ending position in the winding process. The tension of the pole piece is lost in the winding process to cause various adverse effects, for example, the pole piece cannot be tightly attached to the diaphragm due to no tension in the mechanical stretching direction (machine direction, MD), the interface is easy to wrinkle after the battery cell is charged and discharged, and risks such as pole piece breakage and the like can occur in serious cases; and when the anode pole piece and the cathode pole piece are in tension-free ending, pole piece fluctuation in the transverse (transverse direction, TD) and other vertical mechanical directions is increased, so that the anode exceeds the cathode dimension (AC OH) abnormality, the risks of battery capacity deficiency, lithium analysis and the like are easily caused, and the influence is serious.

Disclosure of Invention

The application provides an electrode assembly and a battery cell head winding method, wherein a first pole piece between a diaphragm and the diaphragm is synchronously cut during winding, so that the pole piece and the diaphragm in the battery cell are in a continuous tension state in the whole winding process, the design that the head pole piece and the diaphragm are continuously wound is finally achieved, and the design that the anode area in the battery cell design is larger than that of a cathode can be met.

In a first aspect, the present application provides an electrode assembly comprising: the first diaphragm, the first pole piece, the second diaphragm and the second pole piece are in a winding structure and are sequentially stacked in the same circle;

the first diaphragm, the second diaphragm and a first pole piece positioned between the first diaphragm and the second diaphragm are flush with the head end in the core of the electrode assembly, the first pole piece is an anode piece, the second pole piece is a cathode piece, or the first pole piece is a cathode piece, and the second pole piece is an anode piece.

According to the method, the first diaphragm, the second diaphragm and the first pole piece between the first diaphragm and the second diaphragm are in a flush state and enter the winding mechanism, so that the pole piece and the diaphragm in the battery cell can be guaranteed to be in a continuous tension state in the whole winding process, the design that the head pole piece and the diaphragm are continuously wound is finally achieved, and the design that the anode area in the battery cell design is larger than that of the cathode can be met.

In a possible implementation manner, the first pole piece includes a first section and a second section, the second section is located at the head end in the core of the first pole piece, the first section includes a first current collector layer and active material layers on two sides of the first current collector layer, the active material layers on two sides are respectively and directly attached to the first diaphragm and the second diaphragm, the second section includes a second current collector layer, two sides of the second current collector layer are respectively and directly attached to the first diaphragm and the second diaphragm, and the second current collector layer and the first current collector layer are connected or are in an integrated structure.

In a possible implementation manner, the first pole piece includes a first section and a fourth section, the fourth section is connected to one end of the first section, the first section includes a first current collector layer and active material layers on two sides of the first current collector layer, the active material layers on two sides are respectively and directly attached to the first diaphragm and the second diaphragm, the fourth section includes a fourth current collector layer and an active material layer located on one side of the fourth current collector layer, the active material layer is directly attached to the first diaphragm and the second diaphragm respectively on the other side of the fourth current collector, or the active material layer is directly attached to the second diaphragm and the first diaphragm respectively on the other side of the fourth current collector.

In a possible implementation manner, the first pole piece includes a second section, the second section is located at the first end in the core of the first pole piece, the second section includes a second current collector layer, two sides of the second current collector layer are respectively and directly attached to the first diaphragm and the second diaphragm, and the fourth section is connected with one end of the first section, which is away from the second section, or the fourth section is connected with the first section and the second section.

In one possible implementation, the length of the fourth section is smaller than the perimeter length of the anode sheet of the outermost ring of the electrode assembly.

In one possible implementation, at least one of the first diaphragm, the first pole piece, the second diaphragm, and the second pole piece is connected with a connection film at a head end in the core.

In one possible implementation, the first separator, the first pole piece, the second separator, and the second pole piece are flush at a head end within a core of the electrode assembly.

In a second aspect, the present application provides a method for winding a cell header, including the steps of:

the winding mechanism is used for fixing the head end of a first electric core material in the electric core materials, the first electric core material comprises a first pole piece, a first diaphragm and a second diaphragm, the first diaphragm and the second diaphragm are positioned on two sides of the first pole piece, and the first diaphragm, the first pole piece and the second diaphragm are flush at the winding head end;

The first battery core material is in a stretching state, the head end of a second battery core material is sent to the winding mechanism, the second battery core material comprises a second pole piece, the first pole piece is an anode piece, the second pole piece is a cathode piece, or the first pole piece is a cathode piece, and the second pole piece is an anode piece;

the winding mechanism winds the first battery core material and the second battery core material to form an electrode assembly, and the first diaphragm, the first pole piece, the second diaphragm and the second pole piece are sequentially stacked in the same circle.

In a possible implementation manner, the first pole piece is an anode piece, the second pole piece is a cathode piece, the first electric core material is wound by the winding mechanism in a stretching state, and after the winding angle is larger than a first preset angle, the first end of the second electric core material is sent to the winding mechanism, and the first electric core material and the second electric core material are wound by the winding mechanism to form an electrode assembly.

In a possible implementation manner, the head end of the cathode sheet wound on the winding mechanism is provided with a second cathode section, the second cathode section comprises a second cathode current collector layer, two sides of the second cathode current collector layer are respectively and directly attached to the first diaphragm and the second diaphragm, and the first diaphragm and the second diaphragm are covered and attached to two side surfaces of the second cathode current collector layer.

In a possible implementation manner, the first pole piece is a cathode piece, the second pole piece is an anode piece, the second cathode section is a second end at one end facing away from the winding core, the second anode section is a first end at one end facing away from the winding core, and the second end is level with the first end, or the second end is located at one side of the first end facing away from the winding core along the winding direction.

In a third aspect, the present application provides a cell winding apparatus comprising:

a first winding mechanism for winding an electrode material including an anode sheet, a cathode sheet, and a separator to form an electrode assembly;

the first feeding mechanism is positioned at the feeding front end of the first winding mechanism and is used for fixing at least part of the battery cell materials and feeding the battery cell materials into the first winding mechanism;

the second feeding mechanism is positioned at the feeding front end of the first winding mechanism and is used for fixing at least part of the battery cell materials and feeding the battery cell materials into the first winding mechanism;

the cutting mechanism is positioned at the front end of the feeding of the first winding mechanism and is used for synchronously cutting the electric core materials conveyed to the first winding mechanism by the first feeding mechanism and the second feeding mechanism.

This application is through setting up cutting mechanism between feeding mechanism and first winding mechanism, after a single electrode assembly is accomplished to first winding mechanism, under the state that the electric core material keeps tensile, cuts electric core material through cutting mechanism synchronization, and electric core material cuts the end under tensile state, need not cut for many times, only need once cut after every electrode assembly winds to accomplish, the effectual supplementary duration of reducing the winding. In addition, the first pole piece clamped between the two layers of diaphragms and the diaphragms are cut synchronously, the first pole piece is not required to be fed between the two layers of diaphragms when the next electrode assembly is wound, actions such as feeding, roller feeding and the like in the process are saved, and the auxiliary winding time is further reduced; and the first pole piece is not required to be fed between the two layers of diaphragms, dislocation and wrinkling phenomena of the middle first pole piece in the process can not occur, the flattening degree of the anode piece and the cathode piece in the initial winding process of the next electrode assembly is improved, and the quality of the electrode assembly after winding and forming is improved.

In a possible implementation manner, the first feeding mechanism includes a first roller, a second roller and a first driving mechanism, the first roller and the rotating shaft of the second roller are parallel, the first roller and the second roller are used for clamping, fixing and feeding the battery cell material in a rotating mode, and the first driving mechanism is used for driving the first roller and/or the second roller to rotate.

In a possible implementation manner, the battery cell winding device further comprises a second winding mechanism, wherein the second winding mechanism is located between the first feeding mechanism and the first winding mechanism and is used for fixing and winding the battery cell material between the first feeding mechanism and the first winding mechanism.

In a possible implementation, the cutting mechanism is located between the first winding mechanism and the second winding mechanism.

In a possible implementation manner, the second feeding mechanism includes a third roller shaft, a fourth roller shaft and a second driving mechanism, the rotation shafts of the third roller shaft and the fourth roller shaft are parallel, the third roller shaft and the fourth roller shaft are used for clamping and fixing the battery cell material, and the second driving mechanism is used for driving the third roller shaft and/or the fourth roller shaft to rotate.

In a possible implementation manner, the second feeding mechanism further includes a fifth roller shaft and a first displacement mechanism, where the first displacement mechanism is used to drive the fourth roller shaft to approach or depart from the third roller shaft, and is used to drive the fourth roller shaft and the fifth roller shaft to approach or depart from each other.

In a possible implementation manner, the battery core winding device further includes a second winding mechanism, the fourth roller shaft and the fifth roller shaft are located between the first winding mechanism and the second winding mechanism, the fourth roller shaft and the fifth roller shaft are in a mutually-far state, and a channel is formed between the fourth roller shaft and the fifth roller shaft, and the channel is used for the second winding mechanism to pass through.

In a possible implementation manner, the battery cell winding device further comprises a third winding mechanism and a second displacement mechanism, wherein the second displacement mechanism is used for driving the winding mechanism to exchange positions.

In a possible implementation manner, the first winding mechanism, the second winding mechanism and the third winding mechanism are distributed in a triangle shape, and the winding mechanisms are used for exchanging positions along a straight line.

In a possible implementation manner, the second direction is a direction perpendicular to a plane in which the winding direction of the winding mechanism is located, the winding mechanism and the first feeding mechanism are relatively slidably disposed along the second direction, and/or the winding mechanism and the second feeding mechanism are relatively slidably disposed along the second direction.

In a possible implementation manner, the battery cell winding device further comprises a rubberizing mechanism, wherein the rubberizing mechanism is used for rubberizing the tail end of the electrode assembly wound by the winding mechanism so as to fix the winding tail end of the electrode assembly.

In a possible implementation manner, the winding mechanism comprises a first clamping part and a second clamping part, and a containing part is arranged between the first clamping part and the second clamping part and is used for containing the battery cell material;

The first clamping part and the second clamping part slide relatively along a first direction, the first direction is the direction that the first clamping part faces the second clamping part, and the first clamping part and the second clamping part are used for clamping and fixing the battery cell material.

In a possible implementation manner, the winding mechanism has a winding surface for winding the battery cell material, the winding surface includes a first winding surface and a second winding surface, the first winding surface includes an outer wall surface of the first clamping portion facing away from the second clamping portion, and the second winding surface includes an outer wall surface of the second clamping portion facing away from the first clamping portion.

In one possible embodiment, the winding surface is provided with a recess.

In a fourth aspect, the present application provides a method for winding a battery cell, including the steps of:

a first electrode plate is clamped between the two layers of diaphragms to form a first battery core material, and the first electrode plate is one of an anode plate and a cathode plate;

the first winding mechanism winds the first battery core material and the second battery core material in a first area, wherein the first battery core material and the second battery core material are in a stretching state, the second battery core material is a second pole piece, the second pole piece is one of the anode piece and the cathode piece, and the polarity of the first pole piece in the first battery core material is different from the polarity of the second pole piece in the second battery core material;

The first winding mechanism stops winding to form a battery core winding body, the second winding mechanism fixes the first battery core material in a second area, the second feeding mechanism fixes the second battery core material, and the cutting mechanism synchronously cuts the first battery core material and the second battery core material between the first winding mechanism and the second winding mechanism;

the second winding mechanism moves to the first area, the second feeding mechanism feeds the second electric core material into the second winding mechanism, and the second winding mechanism winds the first electric core material and the second electric core material so as to wind the other electric core winding body.

In one possible implementation, the first winding mechanism is moved to a third region before or while the second winding mechanism is moved to the first region, and the rubberizing mechanism rubberizes the tail end of the electrode assembly, which is wound by the first winding mechanism.

In a possible implementation, a third winding mechanism is moved to the second region before or while the first winding mechanism is moved to the third region.

In a possible implementation manner, after the second winding mechanism located in the first area stops winding to form the electrode assembly, the third winding mechanism fixes the first cell material in the second area, the second feeding mechanism fixes the second cell material, and a cutting mechanism cuts the first cell material and the second cell material between the third winding mechanism and the second winding mechanism synchronously.

In a possible implementation manner, during the winding process of the winding mechanism located in the first area, the fourth roller shaft and the fifth roller shaft of the second feeding mechanism clamp the second electric core material, and the fourth roller shaft and the fifth roller shaft rotate to feed the second electric core material into the winding mechanism located in the first area.

In a possible implementation manner, after or while the winding mechanism located in the first area stops winding, the third roller shaft and the fourth roller shaft of the second feeding mechanism are close to each other to clamp and fix the second cell material, and the fourth roller shaft and the fifth roller shaft are far away from each other to give way when the winding mechanism located on the second area moves to the first area.

In a possible implementation manner, the first electrode sheet is an anode sheet, the second electrode sheet is a cathode sheet, and after the winding mechanism in the first area winds the first core material by more than a first preset angle, the second feeding mechanism feeds the second core material into the winding mechanism in the first area for winding.

In a fifth aspect, the present application provides an electrode assembly comprising: comprising the following steps: the first diaphragm, the first pole piece, the second diaphragm and the second pole piece are in a winding structure and are sequentially stacked in the same circle;

The first diaphragm, the first pole piece, the second diaphragm and the second pole piece are flush with the tail end of the periphery of the electrode assembly, the first pole piece is an anode piece, the second pole piece is a cathode piece, or the first pole piece is a cathode piece, and the second pole piece is an anode piece.

According to the method, through synchronous cutting, the scheme that the anode sheet, the cathode sheet and the diaphragm are cut together is adopted, so that the pole piece and the diaphragm in the battery cell are in a continuous tension state in the whole winding process, the design that the tail pole piece is flush with the diaphragm is finally achieved, and meanwhile the design that the anode area in the battery cell design is larger than that of the cathode can be met.

In one possible implementation, the first separator, the second separator, and a first pole piece between the first separator and the second separator are flush at a head end within a core of the electrode assembly.

In one possible implementation, the first diaphragm, the first pole piece, the second diaphragm, and the second pole piece are connected with a connecting film at the peripheral tail end which is flush.

In a possible implementation manner, the first pole piece includes a first section and a third section, the third section is located at a peripheral tail end of the first pole piece, the first section includes a first current collector layer and active material layers on two sides of the first current collector layer, the active material layers on two sides are respectively and directly attached to the first diaphragm and the second diaphragm, the third section includes a third current collector layer, two sides of the third current collector layer are respectively and directly attached to the first diaphragm and the second diaphragm, and the third current collector layer and the first current collector layer are connected or are in an integrated structure.

In a possible implementation manner, the first pole piece includes a third section, the third section is located at a peripheral tail end of the first pole piece, the third section includes a third current collector layer, two sides of the third current collector layer are respectively and directly attached to the first diaphragm and the second diaphragm, and the fourth section is connected with one end of the first section, which is away from the third section, or the fourth section is connected with the first section and the third section.

In a sixth aspect, the present application provides a method for winding a battery cell, including the steps of:

the first battery cell material and the second battery cell material are wound by a winding mechanism in a stretching state, wherein the first battery cell material comprises a first pole piece, a first diaphragm and a second diaphragm which are positioned on two sides of the first pole piece, the second battery cell material comprises a second pole piece, the first pole piece is an anode piece, the second pole piece is a cathode piece, or the first pole piece is a cathode piece, and the second pole piece is an anode piece;

after winding of the winding mechanism is finished, the first electric core material and the second electric core material are synchronously cut, the first electric core material and the second electric core material are coplanar with each other on the section of the tail end of the winding mechanism, the first diaphragm, the first pole piece, the second diaphragm and the second pole piece are flush with each other on the tail end of winding and ending, and the first diaphragm, the first pole piece, the second diaphragm and the second pole piece are sequentially stacked in the same circle to form an electrode assembly.

In a possible implementation manner, the peripheral tail end of the cathode sheet wound on the winding mechanism is provided with a third cathode section, the third cathode section comprises a third cathode current collector layer, two sides of the third cathode current collector layer are respectively and directly attached to the first diaphragm and the second diaphragm, and the first diaphragm and the second diaphragm are covered and attached to two side surfaces of the third cathode current collector layer.

In a possible implementation manner, a third anode section is arranged at the peripheral tail end of the anode sheet wound on the winding mechanism, the third anode section comprises a third anode current collector layer, two sides of the third anode current collector layer are respectively and directly attached to the first diaphragm and the second diaphragm, and the first diaphragm and the second diaphragm are covered and attached to two side surfaces of the third anode current collector layer.

In a possible implementation manner, the first pole piece is a cathode piece, the second pole piece is an anode piece, the second pole piece is located on the inner side of the winding of the first pole piece, and the length of the third cathode section is greater than the sum of the peripheral perimeter of the electrode assembly and the length of the third anode section.

In one possible implementation, the electrode assembly is terminated by rubberizing at the co-planar ends after the first and second cell materials are cut simultaneously.

Drawings

Fig. 1 is a schematic diagram of a first embodiment of a battery cell winding device;

fig. 2 is a schematic diagram two of a battery core winding device according to an embodiment of the present application;

fig. 3 is a schematic diagram III of a battery cell winding device according to an embodiment of the present application;

fig. 4 is a schematic diagram fourth of a battery cell winding device provided in an embodiment of the present application;

FIG. 5 is a schematic view of a winding mechanism provided in an embodiment of the present application;

fig. 6 is a schematic diagram of a triangle structure of a battery core winding device according to an embodiment of the present application;

fig. 7 is a schematic diagram II of a triangle structure of a battery core winding device according to an embodiment of the present application;

fig. 8 is a schematic diagram of an operating state of a battery cell winding device according to an embodiment of the present application;

fig. 9 is a flowchart of a method for winding a battery cell according to an embodiment of the present application;

fig. 10 (a) is a schematic view of an electrode assembly according to an embodiment of the present application;

fig. 10 (b) is a schematic view of the innermost core material of the core material of fig. 10 (a);

fig. 10 (c) is a schematic diagram of a second electrode assembly according to an embodiment of the present disclosure;

Fig. 10 (d) is a schematic view of an electrode assembly according to an embodiment of the present application;

fig. 10 (e) is a schematic diagram of an electrode assembly according to an embodiment of the present application;

FIG. 10 (f) is a schematic view of a tile and a bend provided by an embodiment of the present application;

FIG. 10 (g) is a schematic illustration of a fourth anode segment provided in an embodiment of the present application;

fig. 11 (a) is a schematic diagram fifth of an electrode assembly provided in an embodiment of the present application;

fig. 11 (b) is a schematic diagram six of an electrode assembly provided in an embodiment of the present application;

fig. 11 (c) is a schematic diagram seven of an electrode assembly provided in an embodiment of the present application;

fig. 11 (d) is a schematic view eight of an electrode assembly provided in an embodiment of the present application;

FIG. 11 (e) is a second schematic illustration of a fourth anode segment provided in an embodiment of the present application;

FIG. 12 is a schematic view of a second cathode section provided in an embodiment of the present application;

FIG. 13 is a schematic view of a second anode segment provided in an embodiment of the present application;

fig. 14 is a flowchart of an electrode assembly head winding method provided in an embodiment of the present application;

fig. 15 is a schematic view of an electrode assembly unloading profiling flow provided in an embodiment of the present application;

FIG. 16 is a schematic view of a third cathode section provided in an embodiment of the present application;

FIG. 17 is a schematic view of a third anode segment provided in an embodiment of the present application;

fig. 18 is a schematic view of a first core material provided in an embodiment of the present application;

fig. 19 is a second schematic view of a core material provided in an embodiment of the present application;

fig. 20 is a schematic diagram of a third embodiment of a core material provided herein;

fig. 21 is a schematic diagram of a fourth core material provided in an embodiment of the present application;

fig. 22 is a schematic diagram of a core material provided in an embodiment of the present application;

fig. 23 is a schematic view of a core material provided in an embodiment of the present application;

fig. 24 is a schematic view of a seventh electrical core material provided in an embodiment of the present application;

fig. 25 is a schematic view of a core material provided in an embodiment of the present application.

Detailed Description

Embodiments of the present application are described below with reference to the accompanying drawings in the embodiments of the present application.

For convenience of understanding, the following description will explain and describe english abbreviations and related technical terms related to the embodiments of the present application.

It should be understood that the described embodiments are merely some, but not all, of the embodiments of the present application. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present disclosure.

The terminology used in the embodiments of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in this application and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

It should be understood that the term "and/or" as used herein is merely one of the same fields describing the associated object, meaning that there may be three relationships, e.g., a and/or B, may represent: a exists alone, A and B exist together, and B exists alone. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.

The term "if" as used herein may be interpreted as "at" or "when" depending on the context "or" in response to a determination "or" in response to a detection. Similarly, the phrase "if determined" or "if detected (stated condition or event)" may be interpreted as "when determined" or "in response to determination" or "when detected (stated condition or event)" or "in response to detection (stated condition or event), depending on the context.

It is to be understood that the use of "first," "second," etc. herein is for descriptive purposes only and is not to be construed as indicating or implying any relative importance or order.

In the description of the present application, the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate an orientation or positional relationship based on that shown in the drawings, merely for convenience of description and to simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present application.

As used herein, "within a range," unless otherwise indicated, includes both ends of the range by default, e.g., in the range of 1 to 5, including both values of 1 and 5.

In the description of the present application, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, a fixed connection, a removable connection, an interference connection, or an integral connection; the specific meaning of the terms in this application will be understood by those of ordinary skill in the art based on the specific circumstances.

The application provides a battery core winding device which is used for winding an electrode assembly, wherein the electrode assembly generates oxidation-reduction reaction when a battery and the like store electricity and discharge electricity.

Referring to fig. 1, the cell winding apparatus 100 includes a first winding mechanism 110, a first feeding mechanism 120, a second feeding mechanism 130, and a cutting mechanism 140.

The first winding mechanism 110 is used for winding a battery cell material, wherein the battery cell material 200 includes an anode sheet 210, a cathode sheet 220, and a separator 230, and the anode sheet 210, the cathode sheet 220, and the separator 230 are stacked and wound by the first winding mechanism 110 to form an electrode assembly 240.

Referring to fig. 1, the first winding mechanism 110 may fix the head of the battery cell material 200 and wind the battery cell material 200 into a continuous multi-turn structure by rotating to form the electrode assembly 240.

Wherein the separator 230 may have two layers, the anode sheet 210 may be positioned between the two layers of the separator 230, and the cathode sheet 220 is positioned outside the two layers of the separator 230. Alternatively, the cathode tab 220 may be positioned between the two separator films 230, and the anode tab 210 is positioned outside the two separator films 230. The two-layer separator 230 is constructed such that any adjacent anode sheet 210 and cathode sheet 220 (refer to two layers adjacent in the radial direction of the electrode assembly) in the wound electrode assembly 240 are separated by the separator 230.

The first feeding mechanism 120 is located at the feeding front end of the first winding mechanism 110, and is used for fixing at least part of the battery core material and feeding the battery core material into the first winding mechanism 110.

The second feeding mechanism 130 is located at the feeding front end of the first winding mechanism 110, and is used for fixing at least part of the battery core material and feeding the battery core material into the first winding mechanism 110.

Referring to fig. 1, the first feeding mechanism 120 may fix the two separator sheets 230 and the anode sheet 210, and the second feeding mechanism 130 may fix the cathode sheet 220. The two layers of the separator 230 and the anode sheet 210 form a first cell material of the present embodiment, in which the anode sheet 210 is sandwiched between the two layers of the separator 230, and the single cathode sheet 220 may form a second cell material of the present embodiment. The first core material is fed into the first winding mechanism 110 by the first feeding mechanism 120 and the second core material is fed into the first winding mechanism 110 by the second feeding mechanism 130.

It should be noted that, in this embodiment, the two layers of the separator 230 and the anode sheet 210 form the first cell material of this embodiment, in which the anode sheet 210 is sandwiched between the two layers of the separator 230, and the single cathode sheet 220 forms the second cell material of this embodiment. In other embodiments, two layers of the separator 230 and the cathode sheet 220 may form the first cell material of the present embodiment, in which the cathode sheet 220 is sandwiched between the two layers of the separator 230, and the single anode sheet 210 forms the second cell material of the present embodiment, which also falls within the protection scope defined in the present application.

The cutting mechanism 140 is located at the feeding front end of the first winding mechanism 110, and is used for synchronously cutting the battery core materials conveyed to the first winding mechanism 110 by the first feeding mechanism 120 and the second feeding mechanism 130. The cutting mechanism 140 may be one, one cutting mechanism 140 cutting the cell material comprising the first cell material and the second cell material in one step.

The cutting mechanism 140 in this embodiment is disposed between the feeding mechanism and the first winding mechanism 110, after the first winding mechanism 110 completes a single electrode assembly 240, the cutting mechanism 140 is used for synchronously cutting the core material in a stretched state, and the core material is cut and terminated in a stretched state, so that multiple times of cutting are not needed, and only one time of cutting is needed after each electrode assembly 240 is wound, so that the auxiliary time of winding is effectively reduced. In addition, the first pole piece clamped between the two layers of diaphragms 230 and the diaphragms are cut synchronously, the first pole piece is not required to be fed between the two layers of diaphragms 230 when the next electrode assembly 240 is wound, actions such as feeding, rolling and the like in the process are saved, and the auxiliary winding time is further reduced; and, there is no need to feed the first pole piece between the two separator layers 230, and the dislocation and wrinkling phenomenon of the first pole piece in the middle in the process does not occur, so that the flattening degree of the anode piece 210 and the cathode piece 220 in the initial winding process of the next electrode assembly 240 is improved, and the quality of the electrode assembly 240 after winding and forming is improved.

In some possible embodiments, referring to fig. 1, the first feeding mechanism 120 may include a first roller 121, a second roller 122, and a first driving mechanism 123, where the axes of rotation of the first roller 121 and the second roller 122 are parallel, and the first roller 121 and the second roller 122 are used to clamp and fix a portion of the cell material 200, for example, in fig. 1, the first roller 121 and the second roller 122 clamp and fix two layers of the separator 230 and the anode sheet 210 located between the two layers of the separator 230.

The first driving mechanism 123 can drive the first roller shaft 121 to rotate, and the second roller shaft 122 is a driven wheel; alternatively, the first driving mechanism 123 may drive the second roller 122 to rotate, and the first roller 121 is a driven wheel; alternatively, the first driving mechanism 123 may simultaneously drive the first roller shaft 121 and the second roller shaft 122 to rotate.

The first roller 121 and the second roller 122 can be rotated relatively to clamp the core material 200 and feed the core material 200 into the first winding mechanism 110.

The first feeding mechanism 120 of this embodiment includes a first roller 121 and a second roller 122, and when the rollers rotate, the electric core material can be conveyed, and when the rollers stop rotating, the first roller 121 and the second roller 122 can clamp and fix the electric core material, so that the functions of conveying and fixing the electric core of the first feeding mechanism 120 can be simultaneously realized.

In some possible embodiments, referring to fig. 3, the second feeding mechanism 130 may include a third roller 131, a fourth roller 132, and a second driving mechanism (not shown in the drawings), where the axes of rotation of the third roller 131 and the fourth roller 132 are parallel, and the third roller 131 and the fourth roller 132 are used to clamp and fix a portion of the battery cell material 200, for example, in fig. 1, the third roller 131 and the fourth roller 132 clamp and fix the cathode sheet 220.

The second driving mechanism can drive the third roll shaft 131 to rotate, and the fourth roll shaft 132 is a driven wheel; alternatively, the second driving mechanism may drive the fourth roller 132 to rotate, and the third roller 131 is a driven wheel; alternatively, the second driving mechanism may simultaneously drive the third roller shaft 131 and the fourth roller shaft 132 to rotate.

The third roller 131 and the fourth roller 132 can be rotated relatively to clamp the core material 200 and feed the core material 200 into the first winding mechanism 110.

The second feeding mechanism 130 of the present embodiment includes a third roller 131 and a fourth roller 132, and when the rollers rotate, the electric core material can be conveyed, and when the rollers stop rotating, the third roller 131 and the fourth roller 132 can clamp and fix the electric core material, so that the functions of conveying and fixing the electric core of the second feeding mechanism 130 can be simultaneously realized.

In some possible embodiments, referring to fig. 2, the cell winding apparatus further includes a second winding mechanism 150, where the second winding mechanism 150 is located between the first feeding mechanism 120 and the first winding mechanism 110, for fixing the cell material between the first feeding mechanism 120 and the first winding mechanism 110.

Wherein, the first winding mechanism 110 does not fix the cell material (first cell material) between the first feeding mechanism 120 and the first winding mechanism 110 when the first winding mechanism 110 winds the cell material composed of the anode sheet 210, the cathode sheet 220 and the separator 230.

When the first winding mechanism 110 completes winding of one electrode assembly, the second winding mechanism 150 fixes the cell material (first cell material) between the first feeding mechanism 120 and the first winding mechanism 110 after stopping the rotation, and the second feeding mechanism 130 stops feeding the first winding mechanism 110 and fixes the second cell material. The cutting mechanism 140 cuts the second feeding mechanism 130 in synchronization with the first winding mechanism 110, and the core material between the second winding mechanism 150 and the first winding mechanism 110, the second winding mechanism 150 being capable of fixing the head of the remaining core material, and the second winding mechanism 150 being capable of fixing the head of the core material to rotate for winding of the next electrode assembly. In one embodiment, when the first winding mechanism 110 and the second winding mechanism 150 are relatively close together, the portion of the cell material head where the second winding mechanism 150 is not fixed does not have a large effect on the winding of the next electrode assembly.

While the second winding mechanism 150 winds the first battery cell material, the second feeding mechanism 130 may feed the second battery cell material into the second winding mechanism 150 to wind to form the next electrode assembly.

In this embodiment, after the cell materials are cut synchronously, the first cell material is fixed by the second winding mechanism 150 and is used as the head of the next electrode assembly to be wound, the second cell material is fixed by the second feeding mechanism 130, and during the cross winding process of the front and rear electrode assemblies, the cell material is always in a stretched state, so that the phenomenon of wrinkling or folding of the cell material during the winding process is effectively prevented. In addition, the second winding mechanism 150 fixes the first cell material, and after the cutting mechanism 140 cuts the first cell material and the second cell material, the second winding mechanism 150 can wind the next electrode assembly and shift to the position where the first winding mechanism 110 is located, so that the transfer efficiency of the front electrode assembly and the rear electrode assembly is effectively improved.

In one embodiment, the cutting mechanism 140 is located between the first winding mechanism 110 and the second winding mechanism 150, and when the first winding mechanism 110 completes an electrode assembly and stops rotating, the second winding mechanism 150 can fix the first battery core material, and the cutting mechanism 140 can cut the second feeding mechanism 130 and the first winding mechanism 110, and the battery core material between the second winding mechanism 150 and the first winding mechanism 110 synchronously, so as to achieve that the battery core material is terminated in a stretched state, and prevent the tail of the electrode assembly from wrinkling or bending. The second winding mechanism 150 may stretch the cell material required for the next electrode assembly.

In one possible embodiment, referring to fig. 3 and 4, the second feeding mechanism 130 further includes a fifth roller 134 and a first displacement mechanism (not shown in the drawings), where the first displacement mechanism is used to drive the fourth roller 132 to approach or separate from the third roller 131, and to drive the fourth roller 132 and the fifth roller 134 to approach or separate from each other.

Referring to fig. 3 and fig. 4, when the first winding mechanism 110 winds the battery core material, the first displacement mechanism drives the fourth roller 132 and the fifth roller 134 to approach each other, and the fourth roller 132 and the fifth roller 134 clamp and fix the second battery core material and feed the second battery core material into the first winding mechanism 110, so as to ensure that the second battery core material entering the first winding mechanism 110 is in a stretched state.

In one embodiment, the battery cell winding apparatus further includes a second winding mechanism 150, the fourth roller 132 and the fifth roller 134 are located between the first winding mechanism 110 and the second winding mechanism 150, the fourth roller 132 and the fifth roller 134 have a passage 135 therebetween in a state of being apart from each other, and the passage 135 is used for the second winding mechanism 150 to pass through.

After the first winding mechanism 110 finishes winding, the first displacement mechanism drives the fourth roller 132 to move to be close to the third roller 131, the third roller 131 and the fourth roller 132 are close to clamp and fix the second battery cell material, and the first displacement mechanism drives the fifth roller 134 to move in a direction away from the fourth roller 132. A channel 135 is formed between the fourth roller 132 and the fifth roller 134, and the width of the channel 135 is larger than the diameter of the second winding mechanism 150, so that the second winding mechanism 150 can pass through the channel 135 and enter the position where the first winding mechanism 110 is located for winding, and the fourth roller 132 and the fifth roller 134 do not interfere with the movement of the second winding mechanism 150.

In one embodiment, the cutting mechanism 140 also has a corresponding displacement mechanism, and the corresponding displacement mechanism of the cutting mechanism 140 can drive the cutting mechanism 140 to move to the outside of the channel 135, so as to prevent the cutting mechanism 140 from interfering with the movement of the second winding mechanism 150.

In some possible embodiments, referring to fig. 2 to 4, the cell winding apparatus further includes a third winding mechanism 160 and a second displacement mechanism (not shown in fig. 2 to 4), where the second displacement mechanism is used to drive the first winding mechanism 110 to move to the position of the third winding mechanism 160, to drive each winding mechanism to exchange positions, such as to drive the third winding mechanism 160 to move to the position of the second winding mechanism 150, and to drive the second winding mechanism 150 to move to the position of the first winding mechanism 110.

Wherein, the first winding mechanism 110, the second winding mechanism 150 and the third winding mechanism 160 have the same composition structure, and the manner and angle of fixing the cell material are the same. The external winding shapes of the first, second and third winding mechanisms 110, 150 and 160 may be identical to wind to form the same-shaped electrode assembly. In one embodiment, the external winding shapes of the first, second and third winding mechanisms 110, 150 and 160 may be different to wind to form differently shaped electrode assemblies.

The delta-shaped winding device formed by the first winding mechanism 110, the second winding mechanism 150 and the third winding mechanism 160, wherein one winding device is used for winding, the other winding device is used for clamping and fixing and winding the next electrode assembly, the other winding device carries the electrode assembly 240 formed by winding, the electrode assembly can move to the rubberizing mechanism 170 for tail end rubberizing, and the rubberized electrode assembly can be used for discharging the electrode assembly. The three winding mechanisms perform different operations at different processes according to the winding process of the electrode assembly, and winding efficiency of the winding device is improved.

In some possible embodiments, referring to fig. 2 to 4, the cell winding apparatus further includes a rubberizing mechanism 170, and the rubberizing mechanism 170 is used for rubberizing the tail end of the electrode assembly 240 wound by the winding mechanism to fix the winding tail end of the electrode assembly 240.

In some possible embodiments, referring to fig. 5, the winding mechanism may be a clamping winding mechanism, and this embodiment is described by taking the first winding mechanism 110 as an example, and the structures and shapes of the second winding mechanism, the third winding mechanism, and other winding mechanisms may be the same as those of the first winding mechanism 110.

In one embodiment, the first winding mechanism 110 includes a first clamping portion 111 and a second clamping portion 112, and a receiving portion 113 is disposed between the first clamping portion 111 and the second clamping portion 112, where the receiving portion 113 is configured to receive the battery cell material.

The first clamping portion 111 and the second clamping portion 112 are of a split structure, an accommodating portion 113 is disposed between the first clamping portion 111 and the second clamping portion 112, the accommodating portion 113 may be an accommodating channel, and the first battery core material may pass through the accommodating portion 113.

The first clamping portion 111 and the second clamping portion 112 move relatively along a first direction, in which the first clamping portion 111 faces the second clamping portion 112, and in this embodiment, the first direction corresponds to the X-axis direction in fig. 5.

When the first clamping portion 111 and the second clamping portion 112 are relatively far away in the first direction, the first cell material is in a free state in the accommodating portion 113, and the first clamping portion 111 and the second clamping portion 112 do not clamp and fix the first cell material. When the first clamping portion 111 and the second clamping portion 112 are relatively close in the first direction, and the first clamping portion 111 and the second clamping portion 112 are both in contact with the first cell material, the first clamping portion 111 and the second clamping portion 112 clamp and fix the first cell material.

In one embodiment, the winding mechanism has a winding surface 114, the winding surface 114 is used for winding the core material, the winding surface 114 includes a first winding surface 1141 and a second winding surface 1142, the first winding surface 1141 includes an outer wall surface of the first clamping portion 111 facing away from the second clamping portion 112, and the second winding surface 1142 includes an outer wall surface of the second clamping portion 112 facing away from the first clamping portion 111.

In one embodiment, the winding surface 114 may have an arcuate shape, and the winding surface 114 may have an arcuate shape to form the cylindrically shaped first winding mechanism 110 shown in fig. 5. In one embodiment, the winding face 114 may be in a plurality of planar shapes to form the prismatic shaped first winding mechanism 110. The shape of the winding surface 114 may be determined according to the overall shape of the winding mechanism, which may be determined according to the shape of the electrode assembly pre-wound by the winding mechanism.

In one embodiment, referring to fig. 5, a recess 1143 is formed on the winding surface 114, the recess 1143 is a groove formed on the winding surface 114, and the recess 1143 penetrates the first winding mechanism 110 in the direction of the Z axis. After the winding mechanism winds the electrode assembly, the electrode assembly needs to be separated from the winding mechanism. When the winding mechanism winds the electrode assembly, the core material is in a stretching state, so that the electrode assembly and the winding mechanism are tightly connected, and the concave portion 1143 is arranged on the winding surface 114, so that the disengaging mechanism of the electrode assembly can conveniently extend between the winding mechanism and the electrode assembly, the electrode assembly is favorably disengaged from the winding mechanism, and the winding efficiency of the electrode assembly is improved.

In an embodiment, referring to fig. 2 to 4, the winding mechanism and the first feeding mechanism 120 are slidably disposed along a second direction, where the second direction is perpendicular to a plane in which the winding direction of the winding mechanism is located, for example, a direction perpendicular to an XY plane formed by an X axis and a Y axis in fig. 4 is the second direction, and may also refer to a direction in which the Z axis in fig. 5 is located. Wherein the winding mechanism may be at least one of the first winding mechanism 110, the second winding mechanism 150, and the third winding mechanism 160.

After the winding mechanism located on the first area 260 completes winding, the first winding mechanism 110 as shown in fig. 2 to 4 completes winding, the second winding mechanism 150 fixes the first cell material, the second feeding mechanism 130 fixes the second cell material, and the cutting mechanism 140 cuts the first cell material and the second cell material simultaneously. After the first winding mechanism 110 moves into the third region 280, the third winding mechanism 160 removes the electrode assembly and moves into the second region 270, and during the movement, the first core material stretched between the second winding mechanism 150 and the first feeding mechanism 120 interferes with the third winding mechanism 160, and the first core material blocks the movement of the third winding mechanism 160 to the second region 270.

In one embodiment, the winding mechanism (including the first winding mechanism 110, the second winding mechanism 150, and the third winding mechanism 160) is movable relative to the entire platform in a second direction perpendicular to the XY plane of fig. 2-4 to enable movement of the winding mechanism to one side of the first and second cell materials through the winding mechanism when in the exchange position to prevent movement interference of the winding mechanism and the cell materials.

In one embodiment, the first feeding mechanism 120 is movable relative to the entire platform in a second direction perpendicular to the XY plane of fig. 2-4, such that the winding mechanism is movable to pass one side of the first and second cell materials when in the exchange position to prevent the winding mechanism and the cell materials from moving past each other.

In one embodiment, the second feeding mechanism 130 is movable relative to the entire platform in a second direction perpendicular to the XY plane of fig. 2-4. The second feeding mechanism 130 moves in a direction perpendicular to the XY plane, preventing the winding mechanism from interfering with the second core material when the winding mechanism exchanges positions, and preventing the winding mechanism from interfering with the second feeding mechanism 130. In this embodiment, the second feeding mechanism 130 and the second core material do not interfere with the winding mechanism, and the second feeding mechanism 130 may be located as close to the first area 260 as possible, so as to facilitate the feeding of the second feeding mechanism 130 to the winding mechanism at the first area 260.

In some possible embodiments, referring to fig. 6 and 7, the first winding mechanism 110, the second winding mechanism 150, and the third winding mechanism 160 are arranged in a triangular configuration, and the winding mechanisms are configured to exchange positions along a straight line.

Referring to fig. 6, when the first winding mechanism 110 winds the electrode assembly, the second winding mechanism 150 and the first battery cell material are not fixed, and the first feeding mechanism 120 and the second feeding mechanism 130 feed the first winding mechanism 110 together. At this time, the fourth roller 132 and the fifth roller 134 of the second feeding mechanism 130 clamp and fix the second core material, and feed the second core material into the first winding mechanism 110.

At this time, the fourth roller 132 and the fifth roller 134 sandwich and fix the second battery cell material between the first winding mechanism 110 and the second winding mechanism 150. Referring to fig. 6, the fourth roller 132 and the fifth roller 134 may commonly clamp the first and second battery cell materials.

Referring to fig. 7, after the first winding mechanism 110 is wound to form an electrode assembly, the first winding mechanism 110 stops rotating, the second winding mechanism 150 clamps and holds the first battery cell material, the fourth roller 132 moves to the third roller 131, the fourth roller 132 and the third roller 131 clamp the second battery cell material, the fifth roller 134 moves to a side far from the fourth roller 132, and a channel 135 is formed between the fourth roller 132 and the fifth roller 134, and the width of the channel 135 is greater than the diameter of the winding mechanism (in this embodiment, the first winding mechanism 110, the second winding mechanism 150 and the third winding mechanism 160 are the same in shape and size and all have cylindrical shapes), so that the second winding mechanism 150 can be displaced to the first region 260 where the first winding mechanism 110 is located through the channel 135.

In addition, the second winding mechanism 150 is linearly displaced to the first region 260, the direction of the first cell material fixed by the second winding mechanism 150 is not required to be changed, the first cell material always extends along one direction and is pulled along one direction in the process of winding the winding mechanism at the first region 260 and the process of exchanging positions of the winding mechanisms at different regions, so that the first cell material is always in a stretched state in the winding process of the electrode assembly, and the first cell material is prevented from being bent and wrinkled or bent when the winding mechanism winds the electrode assembly.

In some possible embodiments, the cell winding apparatus of the above embodiments may employ the following winding method to wind to form an electrode assembly. Referring to fig. 8 and 9 (it should be noted that the 4 states in fig. 8 do not correspond to the four steps in fig. 9, but only the 4 main states of the winding apparatus winding the electrode assembly are shown), the winding method includes the steps of:

in step S100, a first electrode sheet is sandwiched between two layers of the separator 230 to form a first cell material, where the first electrode sheet is one of the anode sheet 210 and the cathode sheet 220.

In this embodiment, the first electrode sheet may be an anode sheet 210, and the first cell material is a three-layer structure in which a layer of anode sheet 210 is sandwiched between two layers of diaphragms 230.

The first feeding mechanism 120 can clamp the first cell material, so that the two layers of diaphragms 230 and the middle anode sheet 210 are relatively clamped and fixed, when the first cell material enters the first winding mechanism 110, the diaphragms 230 and the anode sheet 210 in the first cell material are in a relatively fixed state, and certain displacement between the diaphragms 230 and the anode sheet 210 can not occur, so that the anode sheet 210 can not be wrinkled or bent when the first cell material is wound by the first winding mechanism 110, and the quality of the electrode assembly after winding is improved.

Step S200, the first winding mechanism 110 winds a first electric core material and a second electric core material in a first area 260, the first electric core material and the second electric core material are in a stretched state, the second electric core material is a second electrode sheet, the second electrode sheet is one of the anode sheet 210 and the cathode sheet 220, and the polarity of the first electrode sheet in the first electric core material is different from the polarity of the second electrode sheet in the second electric core material;

it should be noted that, the polarities are different, which means that when the first electrode sheet is the anode sheet 210, the second electrode sheet is the cathode sheet 220; when the first pole piece is the cathode piece 220, the second pole piece is the anode piece 210.

In this step, the second winding mechanism 150 does not fix the first cell material, and the first cell material is stretched by the first feeding mechanism 120 and the first winding mechanism 110, so that the first cell material enters the first winding mechanism 110 in a stretched state, and the anode sheet 210 is not wrinkled or bent, thereby improving the quality of the electrode assembly after winding.

The second cell material and the first cell material synchronously enter the first winding mechanism 110, the second cell material can be clamped between the first cell material and the first winding mechanism 110, and the first cell material and the second cell material are in a stretching state, so that the anode sheet 210 and the cathode sheet 220 cannot be wrinkled and bent, and the quality of the electrode assembly after winding is improved.

In step S300, the first winding mechanism 110 stops winding to form an electrode assembly 240, the second winding mechanism 150 fixes the first cell material in the second region 270, the second feeding mechanism 130 fixes the second cell material, and the cutting mechanism 140 cuts the first cell material and the second cell material between the first winding mechanism 110 and the second winding mechanism 150 simultaneously.

After the electrode assembly wound by the first winding mechanism 110 reaches a predetermined winding length, the first winding mechanism 110 stops winding to form one electrode assembly 240. At this time, the second winding mechanism 150 fixes the first cell material in the second region 270, and the first cell material may be fixed by clamping.

After the second winding mechanism 150 fixes the first battery cell material, the cutting mechanism 140 simultaneously cuts the first winding mechanism 110 and the second winding mechanism 150, and the electrode assembly 240 wound on the first winding mechanism 110 is in a flattened state at the ending.

In one embodiment, the first feeding mechanism 120 stops feeding the first battery cell material to the first winding mechanism 110 while the first winding mechanism 110 stops winding, the second feeding mechanism 130 stops feeding the second battery cell material to the first winding mechanism 110, and the first winding mechanism 110, the first feeding mechanism 120, and the second feeding mechanism 130 may stop rotating at the same time.

In step S400, the second winding mechanism 150 moves to the first region 260, the second feeding mechanism 130 feeds the second core material into the second winding mechanism 150, and the second winding mechanism 150 winds the first core material and the second core material to wind the other electrode assembly 240.

After or while the cutting mechanism 140 simultaneously cuts the first and second battery cell materials between the first and second winding mechanisms 110 and 150, the second winding mechanism 150 fixes the first battery cell material, the electrode assembly 240 wound on the first winding mechanism 110 has substantially completed the winding action, and the first winding mechanism 110 moves to other areas (particularly, may move to the third area, see the embodiment described below) outside the first area 260 with the wound electrode assembly 240 to give way to the second winding mechanism 150. The second winding mechanism 150 moves into the first region 260 and winds the first and second cell materials to wind the other electrode assembly 240.

In the winding process of the two continuous electrode assemblies 240, when the two electrode assemblies 240 are wound and connected, the first electric core material and the second electric core material are synchronously cut and are respectively fixed by the second winding mechanism 150 (the next winding mechanism when the second electrode assembly 240 is connected to the next electrode assembly) and the second feeding mechanism 130, and the first electric core material and the second electric core material are always in a stretched state, so that the first electric core material and the second electric core material can be effectively prevented from being wrinkled or folded when being wound on the winding mechanism. And, the second winding mechanism 150 fixes the first cell material; the second feeding mechanism 130 fixes a second cell material; the cutting mechanism 140 simultaneously cuts the first and second cell materials between the first and second winding mechanisms 110 and 150; and the first winding mechanism 110 moves outside the first region 260; the above-described operations, such as the movement of the second winding mechanism 150 into the first region, may be performed simultaneously, or may be completed in a short time, so that the winding efficiency of the different electrode assemblies 240 may be improved, the ineffective winding time in the winding process may be reduced, and the winding efficiency of the cell winding apparatus may be improved.

In one embodiment, the rubberizing mechanism 170 rubberizes the trailing end of the electrode assembly 240, where the first winding mechanism 110 is wound, before or while the second winding mechanism 150 is moved to the first region 260, and the first winding mechanism 110 is moved to the third region 280.

The rubberizing mechanism 170 rubberizes the tail end of the electrode assembly 240 wound by the winding mechanism to complete the winding operation of the whole electrode assembly, and the electrode assembly can be detached from the winding mechanism and enter the subsequent preparation process.

In one embodiment, the third winding mechanism 160 is moved to the second region 270 to yield the first winding mechanism 110 before or while the first winding mechanism 110 is moved to the third region 280. In one embodiment, the first winding mechanism 110 is moved to the third area 280, the second winding mechanism 150 is moved to the first area 260, the third winding mechanism 160 is moved to the second area 270, and the three movements may be performed simultaneously.

After the winding mechanism at the first region 260 completes winding of one electrode assembly, the electrode assembly moves to the third region 280 for rubberizing; the electrode assembly having the paste applied thereto in the third region 280 is removed from the winding mechanism, and the winding mechanism is moved to the second region 270 to perform a preparation operation of the next electrode assembly; the winding mechanism located at the second region 270 enters the first region 260 to perform winding of the electrode assembly. The winding mechanisms in the three areas alternately complete all actions so as to realize continuous winding of the whole battery core winding equipment on the electrode assembly and improve the winding efficiency.

In one embodiment, after the second winding mechanism 150 located in the first region 260 stops winding to form the electrode assembly 240, the third winding mechanism 160 secures the first cell material in the second region 270, the second feeding mechanism 130 secures the second cell material, and the cutting mechanism 140 simultaneously cuts the first cell material and the second cell material between the third winding mechanism 160 and the second winding mechanism 150.

In one possible embodiment, referring to fig. 1, the second feeding mechanism 130 may include a third roller 131, a fourth roller 132, and a second driving mechanism, the axes of rotation of the third roller 131 and the fourth roller 132 are parallel, and the third roller 131 and the fourth roller 132 are used to clamp and fix a portion of the battery cell material 200, for example, in fig. 1, the third roller 131 and the fourth roller 132 clamp and fix the cathode sheet 220.

In step S300, the third roller 131 and the fourth roller 132 in the second feeding mechanism 130 may clamp and fix the second battery cell material, and feed the winding mechanism by rotation of the third roller 131 and the fourth roller 132. When the feeding is stopped, the third roller 131 and the fourth roller 132 stop rotating and clamp and fix the second cell material.

Referring to fig. 3 and 4, the second feeding mechanism 130 further includes a fifth roller 134 and a first displacement mechanism (not shown in the drawings), where the first displacement mechanism is used to drive the fourth roller 132 to approach or separate from the third roller 131, and to drive the fourth roller 132 and the fifth roller 134 to approach or separate from each other.

Referring to fig. 3, when the first winding mechanism 110 winds the core material, the first displacement mechanism drives the fourth roller 132 and the fifth roller 134 to approach each other, and the fourth roller 132 and the fifth roller 134 clamp and fix the second core material and feed the second core material into the first winding mechanism 110, so as to ensure that the second core material entering the first winding mechanism 110 is in a stretched state.

After or while the winding mechanism located in the first region 260 stops winding, the third roller 131 and the fourth roller 132 of the second feeding mechanism 130 are close to clamp and fix the second battery cell material, and the fourth roller 132 and the fifth roller 134 are far away from each other to give way when the winding mechanism located on the second region 270 moves toward the first region 260.

For example, referring to fig. 8 and 9, in step S300, after the first winding mechanism 110 completes winding, the first displacement mechanism drives the fourth roller 132 to move to approach the third roller 131, the third roller 131 and the fourth roller 132 approach to clamp and fix the second core material, and the first displacement mechanism drives the fifth roller 134 to move in a direction away from the fourth roller 132. A channel 135 is formed between the fourth roller 132 and the fifth roller 134, and the width of the channel 135 is larger than the diameter of the second winding mechanism 150, so that the second winding mechanism 150 can pass through the channel 135 and enter the position where the first winding mechanism 110 is located for winding, and the fourth roller 132 and the fifth roller 134 do not interfere with the movement of the second winding mechanism 150.

During winding of the winding mechanism located in the first region 260, the fourth roller 132 and the fifth roller 134 of the second feeding mechanism 130 clamp the second core material, and the fourth roller 132 and the fifth roller 134 rotate to feed the second core material into the winding mechanism located in the first region 260.

In one embodiment, the first core material includes the anode sheet 210 and the second core material includes the cathode sheet 220, and the second feeding mechanism 130 feeds the second core material into the winding mechanism of the first region 260 for winding after the winding mechanism of the first region 260 winds more than the first preset angle. The active material layer region constituting the anode sheet 210 wraps the active material layer region of the cathode sheet 220.

It can be appreciated that the active material layer region of the anode sheet 210 wraps the active material layer region of the cathode sheet 220, and when the battery is charged, lithium ions in the cathode sheet can be completely received by the anode sheet after being extracted, and are embedded into the first active material layer, so that lithium precipitation is avoided, and safety risks are not caused.

Specifically, the winding mechanism of the first area 260 winds more than a first preset angle, and referring to fig. 8, the winding mechanism of the first area 260 rotates a first preset angle after fixing the first cell material, and then adds a second cell material to the inner side of the first cell material. The first preset angle is a center included angle between two points on a winding surface of the winding mechanism and a center of a circle.

In this embodiment, referring to fig. 10 (a), a first core material includes two separator sheets 230 and an anode sheet 210 located between the two separator sheets 230, a second core material includes a cathode sheet 220, and an electrode assembly 240 formed by winding forms a wound structure of the separator sheet 230-the anode sheet 210-the separator sheet 230-the cathode sheet 220.

In the electrode assembly 240 formed by winding, as shown in fig. 10 (a), the first and second battery materials are stacked and wound one by one to form a multi-winding structure. The winding structure of the separator 230-anode sheet 210-separator 230-cathode sheet 220, or the winding structure of the separator 230-cathode sheet 220-separator 230-anode sheet 210, described in this embodiment and the embodiments below, refers to that when winding, one layer of anode sheet 210 or one layer of cathode sheet 220 is sandwiched between two layers of separator 230, and one layer of anode sheet 210 or one layer of cathode sheet 220 is attached to the outer side of one separator 230, that is, when the electrode assembly is wound, the separator 230-cathode sheet 220-separator 230-anode sheet 210 are sequentially stacked to form a winding single ring body. In the wound electrode assembly 240, the wound single-turn body is repeated in the lamination direction to form the electrode assembly 240 of the multi-layered lamination structure.

Based on the winding method in the above embodiment, the second core material is located between the first core material and the winding surface of the winding mechanism, so the cathode sheet 220 may be located inside the anode sheet 210, and the structure of wrapping the anode sheet 210 around the cathode sheet 220 in the electrode assembly 240 cannot be realized. In this embodiment, after the winding mechanism of the first area 260 winds by more than the first preset angle, the second feeding mechanism 130 feeds the second core material into the winding mechanism at the first area 260 for winding. The winding mechanism winds the first cell material at a first preset angle, so that the anode sheet 210 with a certain winding angle exists at the innermost ring of the electrode assembly, and then the cathode sheet 220 is inserted, so that the structure of the anode sheet 210 wrapping the cathode sheet 220 shown in fig. 10 (a) is formed.

In some possible embodiments, the present application further provides an electrode assembly, referring to fig. 10 (a) and 11 (a), the electrode assembly includes a first electrode sheet, a second electrode sheet, and a separator 230, wherein the separator 230 includes a first separator 231 and a second separator 232, and the first separator 231, the first electrode sheet, the second separator 232, and the second electrode sheet are in a wound structure and are sequentially stacked within the same turn.

When winding, the first pole piece is clamped between the first diaphragm 231 and the second diaphragm 232 to form a first cell material, and the second pole piece is positioned on the inner side of the winding of the first cell material. Referring to fig. 10 (a), the first electrode sheet may be an anode sheet 210 and the second electrode sheet may be a cathode sheet 220; alternatively, referring to fig. 11 (a), the first electrode sheet may be a cathode sheet 220 and the second electrode sheet may be an anode sheet 210.

It should be noted that, the first diaphragm 231, the first pole piece, the second diaphragm 232, and the second pole piece are sequentially stacked in the same circle, and the first core material and the second core material are attached and synchronously enter the winding mechanism when winding, and the four-layer structure entering the winding mechanism can be the same circle. Referring to fig. 10 (b), a first electrode sheet is taken as an anode sheet 210, and a second electrode sheet is taken as a cathode sheet 220. Fig. 10 (b) is a schematic view of the innermost anode tab 210, cathode tab 220 and separator 230 of fig. 10 (a). In fig. 10 (a), the winding direction 300 is a ring-like structure. In fig. 10 (b), a portion of the first core material is wound, and then a second core material is added to the inside of the winding, and the first separator 231, the first electrode sheet, the second separator 232, and the second electrode sheet of the same turn in fig. 10 (b) are stacked in this order. The order of lamination of the first separator 231, the first electrode sheet, the second separator 232, and the second electrode sheet may be different among the first and second cell materials of different turns.

In this embodiment, the first separator 231, the second separator 232, and the first electrode sheet located between the first separator 231 and the second separator 232 are flush with the head end in the core of the electrode assembly, and referring to fig. 10 (a), the first electrode sheet may be the anode sheet 210, and the second electrode sheet may be the cathode sheet 220; alternatively, referring to fig. 11 (a), the first electrode sheet may be a cathode sheet 220 and the second electrode sheet may be an anode sheet 210.

In one embodiment, referring to fig. 10 (a), the first pole piece may be an anode piece 210 and the second pole piece may be a cathode piece 220. Wherein, at the time of winding, the anode sheet 210 may be clamped between the first and second separators 231 and 232 to constitute a first cell material, and the first separator 231, the second separator 232, and the anode sheet 210 in the first cell material are simultaneously cut such that the first separator 231, the second separator 232, and the middle-clamped anode sheet 210 are flush at the core head end of the electrode assembly. Referring to fig. 10 (a), the first inner core head end 241a of the first cell material composed of the first separator 231, the second separator 232, and the anode sheet 210 sandwiched therebetween in fig. 10 (a) is flush.

In one embodiment, referring to fig. 11 (a), the first pole piece may be a cathode piece 220 and the second pole piece may be an anode piece 210. Wherein, when winding, the cathode sheet 220 may be clamped between the first separator 231 and the second separator 232 to constitute a first cell material, and the first separator 231, the second separator 232, and the cathode sheet 220 in the first cell material are simultaneously cut such that the first separator 231, the second separator 232, and the cathode sheet 220 clamped therebetween are flush at the head end in the core of the electrode assembly. Referring to fig. 11 (a), the first inner core front end 241a of the first cell material formed by the first separator 231, the second separator 232, and the cathode sheet 220 sandwiched therebetween in fig. 11 (a) is flush with the front end.

In one embodiment, when wound, the first separator 231, the cathode sheet 220, the second separator 232, and the anode sheet 210 are all flush in the in-core head 241 within the electrode assembly 240, regardless of whether the anode sheet 210 or the cathode sheet 220 is sandwiched between the first separator 231 and the second separator 232, the first sheet sandwiched between the first separator 231 and the second separator 232 (e.g., the cathode sheet 220 is sandwiched in fig. 11 (a)), and the second sheet wound inside the second separator 232 (e.g., the anode sheet 210 wound inside in fig. 11 (a)).

When in winding, the first pole piece between the first diaphragm 231 and the second diaphragm 232 is fixed at the inner head end of the core by the first diaphragm 231 and the second diaphragm 232, so that the first pole piece between the first diaphragm 231 and the second diaphragm 232 has a stretching force at the inner head end of the core, the first pole piece is always kept in a flattened state in the winding process, the electrode piece is tightly attached to the diaphragm, the electrode assembly 240 after winding forming is prevented from being folded and bent at the inner head end of the core, and the capacity loss of the battery core is prevented.

In some possible embodiments, the first pole piece may be an anode piece 210 and the second pole piece may be a cathode piece 220, as shown in fig. 10 (a), with the first end of the first cell material in the core flush. The anode tab 210 may be entirely located between the first separator 231 and the second separator 232.

The first electrode sheet includes a first section, which may be the first anode section 215 shown in fig. 10 (a), the first section includes a first current collector layer, which may be the anode current collector layer 212 within the range of the first anode section 215 in fig. 13, and active material layers on both sides of the first current collector layer, which may be the anode active material 213 within the range of the first anode section 215 in fig. 13. In the wound electrode assembly, the anode tab 210 may be entirely located between the first separator 231 and the second separator 232, and the anode active material 213 at both sides of the first electrode sheet is directly attached to the first separator 231 and the second separator 232, respectively.

In this embodiment, the anode tab 210 includes a first anode section 215, and referring to fig. 13, the first anode section 215 may be formed by stacking an anode current collector layer 212 and anode active materials 213 positioned at both sides of the anode current collector layer 212 to form an active material section of the anode tab 210. Similarly, the cathode sheet 220 may include a first cathode section 225 as a second electrode sheet, and as shown in fig. 12, the first cathode section 225 may be formed by stacking a cathode current collector layer 222 and cathode active materials 223 positioned at both sides of the cathode current collector layer 222 to form an active material section of the cathode sheet 220.

In one embodiment, referring to fig. 10 (a), the first cathode section 225 is adjacent to the first anode section 215 on both sides, and the separator 230 is spaced between the first cathode section 225 and the first anode section 215 that are adjacent to each other. Wherein the sub-adjacency of two active material layers means that only one separator 230 is spaced between the anode sheet 210 of the partial section and the cathode sheet 220 of the partial section; sub-abutment of two-layer separator means that only one layer of anode sheet 210 or cathode sheet 220 is spaced between the two-layer separator 230 of the partial section.

In this embodiment, the anode segments 210 are all located between the first separator 231 and the second separator 232, and the corresponding first anode segments 215 are all located between the first separator 231 and the second separator 232. The two sides of the first cathode section 225 of the cathode sheet 220 refer to the two sides of the inner ring and the outer ring, and the two sides of the first cathode section 225 are adjacent to the first anode section 215 for a time, so that the first anode section 215 of the anode sheet 210 wraps the first cathode section 225 of the cathode sheet 220.

It can be appreciated that the first anode section 215 of the anode sheet 210 wraps the first cathode section 225 of the cathode sheet 220, and when the battery is charged, lithium ions in the cathode sheet can be completely received by the anode sheet after being extracted, and can be embedded into the first active material layer, so that lithium precipitation can not occur, and safety risks can not be caused.

In one embodiment, referring to fig. 10 (a), the anode tab 210 of the electrode assembly 240 may include a first anode section 215 at the head end in the core, the cathode tab 220 may include a first cathode section 225 at the head end in the core, the first anode section 215 is entirely located between the first separator 231 and the second separator 232, a portion of the innermost half turn of the first cathode section 225 is adjacent to the second separator 232 at the underside thereof, and a portion of the innermost half turn of the first cathode section 225 is adjacent to the first anode section 215 at the underside thereof. Further, a part of the upper side of the first cathode section 225 of the innermost half turn is adjacent to the second separator 232, and a part of the upper side of the first cathode section 225 of the innermost half turn is adjacent to the first anode section 215 a plurality of times, and the first anode section 215 (active material section) of the anode sheet 210 is wrapped around the first cathode section 225 (active material section) of the cathode sheet 220.

Referring to fig. 10 (b), fig. 10 (b) is a schematic view of the innermost anode tab 210, cathode tab 220 and separator 230 of fig. 10 (a). In fig. 10 (a), the winding direction 300 is a ring-like structure. In fig. 10 (b), the in-core head end of the first cell material composed of the first separator 231, the anode tab 210, and the second separator 232 is a first in-core head end 241a, the in-core head end of the cathode tab 220 is a second in-core head end 241b, and the second in-core head end 241b of the cathode tab 220 is located on one side of the first in-core head end 241a of the first cell material along the winding direction 300. During winding, the first end 241a in the first core together with the protruding parts of the first separator 231, the anode sheet 210 and the second separator 232 may be wound first along the winding direction 300, and after a part of the winding, the cathode sheet 220 is added to the inner side of the winding, and the first separator 231, the anode sheet 210, the second separator 232 and the cathode sheet 220 are wound together to form an electrode assembly structure shown in fig. 10 (a), in which the first wound half-turn anode sheet 210 is located above the innermost half-turn cathode sheet 220, so as to ensure that the anode sheet 210 can fully wrap the cathode sheet 220 in the electrode assembly 240 formed by winding.

The winding direction 300 is a winding direction of the cell material in the electrode assembly, and fig. 10 (a) may be referred to specifically. The winding core 242 is the center of the electrode assembly, and the head end 241 in the core is the starting end of the cell material in the electrode assembly 240. Referring to fig. 10 (a), the first in-core leading end 241a of the electrode assembly in fig. 10 (a) is a leading end of a first cell material composed of the first separator 231, the anode sheet 210 and the second separator 232, and the second in-core leading end 241b is a winding leading end of a second cell material composed of the cathode sheet 220.

In the first in-core head end 241a of the first cell material, the first separator 231, the anode sheet 210 and the second separator 232 are flush at the first in-core head end 241a, and after the first cell material is synchronously cut, the first in-core head end 241a of the first cell material flush is sent into a winding mechanism for winding. Also, the first in-core head end 241a of the first cell material may be located at a side of the second in-core head end 241b of the second cell material facing away from the winding direction 300 (see fig. 10 (b)). During winding, the first core material is first wound by a first preset angle, the first preset angle in fig. 10 (a) is about 180 degrees, the first core material is first wound by about half the length of the circumference of the innermost ring, and then the second core material is fed, at this time, the second core inner head end 241b of the second core material is located at the rear end of the first core inner head end 241a of the first core material, so as to ensure that the structure of the anode sheet 210 wrapping the cathode sheet 220 is always maintained in the electrode assembly 240.

In one embodiment, referring to fig. 10 (c), the first pole piece is an anode piece 210 and the second pole piece is a cathode piece 220. The first separator 231, the anode tab 210, and the second separator 232 constitute a first cell material, the first tab includes a first section, which may be the first anode section 215 of the anode tab 210, and the cathode tab 220 constitutes a second cell material. In this embodiment, the first cell material is wound once and then the second cell material is sandwiched between the inner sides. And, the first in-core head end 241a of the first cell material and the second in-core head end 241b of the second cell material are flush, and the first in-core head end 241a of the first cell material is located inside the winding of the second in-core head end 241b of the second cell material. In this embodiment, the first cathode section 225 is also adjacent to the first anode section 215 on both sides, and the first anode section 215 of the anode tab 210 wraps the first cathode section 225 of the cathode tab 220.

In one embodiment, referring to fig. 10 (d), the first separator 231, the anode tab 210, and the second separator 232 constitute a first cell material, and the anode tab 210 may include a first anode section 215, and the cathode tab 220 constitutes a second cell material. In this embodiment, the first cell material is wound more than once and then the second cell material is sandwiched inside. And, the first in-core head end 241a of the first cell material is flush, the first in-core head end 241a of the first cell material is located on the right side of the second in-core head end 241b of the second cell material, and the first in-core head end 241a of the first cell material is located on the winding inner side of the second in-core head end 241b of the second cell material. In this embodiment, the first cathode section 225 is also adjacent to the first anode section 215 on both sides, and the first anode section 215 of the anode tab 210 wraps the first cathode section 225 of the cathode tab 220.

In one embodiment, referring to fig. 10 (e), the first electrode sheet is an anode sheet 210, the second electrode sheet is a cathode sheet 220, the anode sheet 210 is entirely located between the first separator 231 and the second separator 232, and the first separator 231, the anode sheet 210 and the second separator 232 form a first cell material. The first pole piece comprises a first section, which may be a first anode section 215 of the anode piece 210, the first pole piece further comprises a second section, the second section is located at the head end in the core of the first pole piece, the second section comprises a second current collector layer, two sides of the second current collector layer are respectively and directly attached to the first diaphragm and the second diaphragm, and the second current collector layer and the first current collector layer are connected or are in an integrated structure. In the present embodiment, referring to fig. 10 (e) and 13, the second section may be the second anode section 211 of the anode sheet 210, and the second anode section 211 is located at the opposite side of the first anode section 215 in the winding direction 300, and the first anode section 215 and the second anode section 211 are connected at the first end 211 a. The end of the second anode section 211 facing away from the first end 211a is a first in-core head end 241a of the first cell material.

The second current collector layer may be an anode current collector layer 212 within the range of the second anode section 211 in fig. 13, and anode active materials 213 are not disposed on two sides of the second current collector layer to form an inactive layer-free region, the second anode section 211 only comprises the anode current collector layer, and at least one side of the second anode section 211 is in adhesive connection with the separator 230. Wherein, at the connection of the second anode section 211 and the first anode section 215, the anode current collector layer 212 is of a unitary structure and is not broken.

In one embodiment, referring to fig. 10 (e), the anode sheet 210 is entirely located between the first separator 231 and the second separator 232, the first separator 231, the anode sheet 210 and the second separator 232 constitute a first cell material, and the cathode sheet 220 constitutes a second cell material to be wound inside the winding of the first cell material. The cathode sheet 220 may include a first cathode section 225 and a second cathode section 221, the second cathode section 221 being located at a side of the first cathode section 225 opposite to the winding direction 300, and the second cathode section 221 being located at the first cathode section 225 connected at the second end 221 a. The end of the second cathode section 221 facing away from the second end 221a is a second in-core head end 241b of the second cell material.

Referring to fig. 12, the first cathode section 225 of the cathode sheet 220 is formed by stacking a cathode current collector layer 222 in the middle and cathode active materials 223 located at both sides of the cathode current collector layer 222. The second cathode section 221 is formed without providing the cathode active material 223 on both sides of the cathode current collector layer 222 of the partial region. Wherein, at the connection of the first cathode section 225 and the second cathode section 221, the cathode current collector layer 222 is of a unitary structure, and is not broken.

In one embodiment, referring to fig. 10 (e), the anode sheet 210 may include a portion of the second anode section 211, the second anode section 211 may be located near the head end side of the core, and both sides of the second anode section 211 are respectively bonded to the first separator 231 and the second separator 232; the cathode sheet 220 may include a portion of the second cathode section 221 as a second electrode sheet, and the second cathode section 221 may be positioned near the head end side in the core, and both sides of the second cathode section 221 are respectively bonded to the first separator 231 and the second separator 232. In this structure, the end of the second anode section 211 connected to the first anode section 215 is a first end 211a, and the end of the second cathode section 221 connected to the first cathode section 225 is a second end 221a. The first end 211a is located at the winding inner side of the second end 221a, and the second end 221a is located at one side of the first end 211a in the winding direction 300 such that both sides of the first cathode section 225 are adjacent to the first anode section 215, constituting the structure in which the first anode section 215 of the anode sheet 210 wraps around the first cathode section 225 of the cathode sheet 220.

The anode sheet 210 and/or the cathode sheet 220 has an inactive layer region at the head end in the core, and is mainly that a certain inactive layer region is required to be disposed at the tail end of the outer periphery of the outermost ring of the electrode assembly. Referring to fig. 10 (a), the anode sheet 210 and the cathode sheet 220 are provided with inactive layer regions at the peripheral tail ends, namely, the third anode section 214 and the third cathode section 224, respectively, in this embodiment, the separator 230, the anode sheet 210 and the cathode sheet 220 may be cut simultaneously when the electrode assembly is wound and terminated, and the cutting position may be at the inactive layer region (refer to fig. 19 and the corresponding description), and at this time, the cut core material may be used as the core head end of the next electrode assembly, and there may be a part of the inactive layer region.

In some possible embodiments, the first pole piece may be a cathode piece 220 and the second pole piece may be an anode piece 210, as shown in fig. 11 (a). The cathode sheet 220 may be entirely located between the first separator 231 and the second separator 232.

The first electrode sheet includes a first section, which may be the first cathode section 225 shown in fig. 11 (a), the first section includes a first current collector layer, which may be the cathode current collector layer 222 within the first cathode section 225 of fig. 12, and active material layers on both sides of the first current collector layer, which may be the cathode active material 223 within the first cathode section 225 of fig. 12. In the wound electrode assembly, the cathode sheet 220 may be entirely positioned between the first separator 231 and the second separator 232, and the cathode active material 223 on both sides of the first electrode sheet may be directly bonded to the first separator 231 and the second separator 232, respectively.

In this embodiment, the cathode sheet 220 may include a first cathode section 225 as a first electrode sheet, and referring to fig. 12, the first cathode section 225 may be formed by stacking a cathode current collector layer 222 and cathode active materials 223 located at both sides of the cathode current collector layer 222 to form an active material section of the cathode sheet 220. Likewise, the anode tab 210, as a second electrode tab, may include a first anode section 215, and referring to fig. 13, the first anode section 215 may be formed by stacking an anode current collector layer 212 and anode active materials 213 positioned at both sides of the anode current collector layer 212 to form an active material section of the anode tab 210.

In one embodiment, referring to fig. 11 (a), the first cathode section 225 is adjacent to the first anode section 215 on both sides, and the separator 230 is spaced between the first cathode section 225 and the first anode section 215 that are adjacent to each other. Wherein the sub-adjacency of two active material layers means that only one separator 230 is spaced between the anode sheet 210 of the partial section and the cathode sheet 220 of the partial section; sub-abutment of two-layer separator means that only one layer of anode sheet 210 or cathode sheet 220 is spaced between the two-layer separator 230 of the partial section.

In this embodiment, the cathode sheet 220 is entirely located between the first separator 231 and the second separator 232, and the corresponding first cathode section 225 is entirely located between the first separator 231 and the second separator 232. The two sides of the first cathode section 225 of the cathode sheet 220 refer to the two sides of the inner ring and the outer ring, and the two sides of the first cathode section 225 are adjacent to the first anode section 215 for a time, so that the first anode section 215 of the anode sheet 210 wraps the first cathode section 225 of the cathode sheet 220.

It is also understood that the first separator 231 and the second separator 232 sandwich the first cathode section 225 for winding, and that the synchronously wound first separator 231 and second separator 232 are both adjacent to the first anode section 215 on the side facing away from the first cathode section 225, with the adjacent meaning that the first separator 231 and the first anode section 215 are directly adjacent, and that no other structural layer is present between the first separator 231 and the first anode section 215; the second separator 232 and the first anode section 215 are directly adjacent, and no other structural layer is present between the second separator 232 and the first anode section 215.

In this embodiment, the cathode sheet 220 may be entirely located between the first separator 231 and the second separator 232, and the corresponding first cathode section 225 may be entirely located between the first separator 231 and the second separator 232. The first separator 231 is located at its outer ring side adjacent to the cathode sheet 220, and the second separator 232 is located at its inner ring side adjacent to the cathode sheet 220. The outer side of the first separator 231 is directly adjacent to the first anode section 215, and the inner side of the second separator 232 is directly adjacent to the first anode section 215, and the first cathode section 225 of the anode sheet 210 is structured to wrap the first cathode section 225 of the cathode sheet 220.

In one embodiment, referring to fig. 11 (a), the first separator 231, the cathode tab 220, and the second separator 232 constitute a first cell material, and the cathode tab 220 may be partially divided into a first cathode section 225, and the anode tab 210 constitutes a second cell material. In this embodiment, the first core material and the second core material may be fed simultaneously, and the first in-core head end 241a of the first core material is located outside the winding of the second in-core head end 241b of the second core material, where the first in-core head end 241a of the first core material and the second in-core head end 241b of the second core material are flush. In this embodiment, the first electric core material and the second electric core material are fed simultaneously, and the first electric core material or the second electric core material does not need to be wound in advance, so that the electric core material can be saved.

In this embodiment, the first separator 231 and the second separator 232 are adjacent to the first anode segment 215 on the side facing away from the first cathode segment 225, and the first anode segment 215 of the anode sheet 210 wraps the first cathode segment 225 of the cathode sheet 220.

In one embodiment, referring to fig. 11 (b), the first end in the core of the anode sheet 210 in the electrode assembly 240 includes a first anode section 215, the first end in the core of the cathode sheet 220 includes a first cathode section 225, the first cathode section 225 is entirely located between a first separator 231 and a second separator 232, and both sides of the first cathode section 225 are adjacent to the first anode section 215, and the first anode section 215 of the anode sheet 210 is configured to wrap the first cathode section 225 of the cathode sheet 220. Wherein the upper spaced portion of the innermost half turn of the second membrane 232 abuts the first anode section 215.

The first separator 231, the cathode tab 220, and the second separator 232 constitute a first cell material, the anode tab 210 constitutes a second cell material, a first in-core head end 241a of the first cell material is located inside winding of a second in-core head end 241b of the second cell material, and the first in-core head end 241a of the first cell material is located on one side of the second in-core head end 241b of the second cell material in the opposite direction to the winding direction 300. In the electrode assembly 240 of the present embodiment, a portion of the first cell material may be wound first, and the second cell material may be fed into the inner side of the first cell material, followed by simultaneous winding.

In one embodiment, referring to fig. 11 (c), the first end in the core of the anode sheet 210 in the electrode assembly 240 includes a first anode section 215, the first end in the core of the cathode sheet 220 includes a first cathode section 225, the first cathode section 225 is entirely located between a first separator 231 and a second separator 232, and both sides of the first cathode section 225 are adjacent to the first anode section 215, and the first anode section 215 of the anode sheet 210 is configured to wrap the first cathode section 225 of the cathode sheet 220.

The first separator 231, the cathode tab 220, and the second separator 232 constitute a first cell material, the anode tab 210 constitutes a second cell material, a first in-core head end 241a of the first cell material is located inside winding of a second in-core head end 241b of the second cell material, and the first in-core head end 241a of the first cell material is located at one side of the second in-core head end 241b of the second cell material in the winding direction 300. In the electrode assembly 240 of this embodiment, a portion of the second core material may be wound first, and the first core material may be fed outside the wound portion of the second core material, followed by synchronous winding.

In this embodiment, the length of the portion of the second core material that is fed into the electrode assembly is not too long, so as to prevent the second core material from winding in an unstretched state, prevent longer wrinkles from occurring in the electrode assembly, improve the winding length of the second core material under the holding of the first core material and the winding mechanism, reduce the wrinkle length of the second core material, and improve the quality of the electrode assembly.

In one embodiment, referring to fig. 11 (d), the cathode sheet 220 is entirely located between the first separator 231 and the second separator 232, the first separator 231, the cathode sheet 220, and the second separator 232 constitute a first cell material, and the anode sheet 210 constitutes a second cell material to be wound inside the winding of the first cell material. The cathode sheet 220 may include a first cathode section 225 and a second cathode section 221, the second cathode section 221 being located at a side of the first cathode section 225 opposite to the winding direction 300, and the second cathode section 221 being connected with the first cathode section 225 at a second end 221 a. The end of the second cathode section 221 facing away from the second end 221a is a second in-core head end 241b of the second cell material.

In this embodiment, the first in-core head end 241a of the first cell material and the second in-core head end 241b of the second cell material may be flush; alternatively, the first in-core head end 241a of the first cell material may be located on one side of the second in-core head end 241b of the second cell material along the winding direction 300; alternatively, the first in-core head end 241a of the first cell material may be located on the opposite side of the second in-core head end 241b of the second cell material in the winding direction 300.

In one embodiment, referring to fig. 11 (d), the first electrode sheet is a cathode sheet 220, the second electrode sheet is an anode sheet 210, the cathode sheet 220 is entirely located between the first separator 231 and the second separator 232, and the first separator 231, the cathode sheet 220, and the second separator 232 form a first cell material. The first pole piece comprises a first section, which may be a first cathode section 225 of the cathode piece 220, the first pole piece further comprises a second section, the second section is located at the head end in the core of the first pole piece, the second section comprises a second current collector layer, two sides of the second current collector layer are respectively and directly attached to the first diaphragm and the second diaphragm, and the second current collector layer and the first current collector layer are connected or are in an integrated structure. In the present embodiment, referring to fig. 11 (d) and 12, the second section may be the second cathode section 221 of the cathode sheet 220, and the second cathode section 221 is located at the opposite side of the first cathode section 225 along the winding direction 300, and the first cathode section 225 and the second cathode section 221 are connected at the second end 221 a. The end of the second cathode section 221 facing away from the second end 221a is a first in-core head end 241a of the first cell material.

The second current collector layer may be a cathode current collector layer 222 within the scope of the second cathode section 221 in fig. 12, the two sides of the second current collector layer are not provided with cathode active materials 223 to form an inactive layer region, the second cathode section 221 only comprises the cathode current collector layer 222, and at least one side of the second cathode section 221 is in adhesive connection with the separator 230. Wherein, at the connection of the second cathode section 221 and the first cathode section 225, the cathode current collector layer 222 is of a unitary structure, and is not broken.

In one embodiment, referring to fig. 11 (d), the cathode sheet 220 is entirely located between the first separator 231 and the second separator 232, the first separator 231, the cathode sheet 220, and the second separator 232 constitute a first cell material, and the anode sheet 210 constitutes a second cell material to be wound inside the winding of the first cell material. The anode tab 210 may include a first anode section 215 and a second anode section 211, the second anode section 211 being located at a side of the first anode section 215 opposite to the winding direction 300, and the first anode section 215 and the second anode section 211 being connected at a first end 211 a. The end of the second anode section 211 facing away from the first end 211a is a first in-core head end 241a of the first cell material.

Referring to fig. 13, the first anode section 215 of the anode tab 210 is formed by stacking an anode current collector layer 212 in the middle and anode active materials 213 located at both sides of the anode current collector layer 212. The second anode section 211 is formed without providing the anode active material 213 on both sides of the anode current collector layer 212 of the partial region. Wherein, at the connection of the second anode section 211 and the first anode section 215, the anode current collector layer 212 is of a unitary structure and is not broken.

In one embodiment, the anode sheet 210 may include a first anode section 215 and a second anode section 211, the cathode sheet 220 may include a first cathode section 225 and a second cathode section 221, and the opposite directions of the first end 211a and the second end 221a along the winding direction 300 may not be limited as long as the first separator 231 and the second separator 232 are adjacent to the first anode section 215 on both sides facing away from the first cathode section 225.

In some possible embodiments, the cathode sheet 220 may include a second cathode section 221, the second cathode section 221 being located at a core front end of the cathode sheet 220, the second cathode section 221 being a cathode current collector layer, at least one side of the second cathode section 221 being directly attached to the separator 230, the separator 230 being a first separator 231 and/or a second separator 232. The cathode current collector layer 222 of the second cathode section 221 may be connected to the cathode current collector layer of the active material layer region in the cathode sheet 220.

For example, in fig. 21, the cathode current collector layer 222 of the second cathode section 221 and the cathode current collector layer 222 of the first cathode section 225 may be two parts and adhesively connected by an adhesive tape. Tape bonding can provide greater extensibility of the core material. The adjacent anode sheet 210, cathode sheet 220 and separator 230 may be more closely adhered to each other when the core material is wound in a stretched state, particularly at the winding head and tail positions, so as to facilitate better winding and form an electrode assembly of a laminated structure.

In one embodiment, referring to fig. 12, the cathode current collector layer 222 of the second cathode section 221 may be of unitary construction with the cathode current collector layer of the first cathode section 225. In preparation, cathode active material 223 is prepared on both sides of cathode current collector layer 222 of the same layer to form first cathode section 225; the cathode active material 223 is not disposed at both sides of the partial region to form the second cathode section 221.

In one embodiment, the anode current collector layer 212 in the second anode section 211 may be connected with the anode current collector layer 212 of the first anode section 215. For example, in fig. 21, the anode current collector layer 212 of the second anode section 211 and the anode current collector layer 212 of the first anode section 215 may be two-part and adhesively connected by an adhesive tape. Tape bonding can provide greater extensibility of the core material. The adjacent anode sheet 210, cathode sheet 220 and separator 230 may be more closely adhered to each other when the core material is wound in a stretched state, particularly at the winding head and tail positions, so as to facilitate better winding and form an electrode assembly of a laminated structure.

In one embodiment, referring to fig. 13, the anode current collector layer 212 of the second anode section 211 may be of unitary construction with the anode current collector layer of the first anode section 215. In the preparation, anode active materials 213 are prepared on both sides of the anode current collector layer 212 of the same layer; the anode active material 213 is not disposed at both sides of the partial region to form the second cathode section 221.

In this embodiment, referring to fig. 10 (f), fig. 10 (f) shows a schematic structural view of an electrode assembly, wherein the electrode assembly is formed by winding a core material into a ring-like structure, and the electrode assembly 240 may include two flat portions 291 distributed in a thickness direction and two curved portions 292 at both ends of the two flat portions 291. The anode sheet 210, the cathode sheet 220, and the separator 230 all extend along a plane within the tiling 291, and the anode sheet 210, the cathode sheet 220, and the separator 230 all extend along an arc surface within the bent 292. The anode sheet 210, the cathode sheet 220, and the separator 230 are connected to one end of the flat portion at both ends of the bent portion 292, respectively (the connection refers only to the connection of the cell material at the connection of the bent portion 292 and the flat portion 291. In an actual product, the cell material is in an integral structure at the middle region of the bent portion 292 and the flat portion 291. The electrode assembly may be formed by one-time winding of the cell material, and the connection includes the connection of the cell material at the connection of the bent portion 292 and the flat portion 291).

Fig. 10 (f) shows a schematic view of an electrode assembly 240 at a viewing angle parallel to a plane of the winding direction 300, in which the cell material extends in a direction perpendicular to the plane, i.e., the anode sheet 210, the cathode sheet 220, and the separator 230 in the electrode assembly 240 are all perpendicular to the plane.

When in winding, the winding head end of the electric core material can firstly extend linearly, and at the moment, one section of the electric core material which firstly extends linearly can form one of the tiling parts 291; the core material is bent and wound to form one of the bent portions 292, and then continues to extend linearly after being bent 180 degrees to form the other flat portion 291; the winding is again bent to form another bent portion 292, and after being bent 180 degrees, is gradually wound outside layer by layer to form the electrode assembly 240 of a ring-shaped structure.

In this embodiment, referring to fig. 10 (f), only the anode sheet 210 is located between the first separator 231 and the second separator 232 to form the first cell material, and the cathode sheet 220 forms the second cell material. Reference is made to the above when the cathode sheet 220 is positioned between the first separator 231 and the second separator 232 to constitute a first cell material and the anode sheet 210 constitutes a second cell material.

In some possible embodiments, see fig. 10 (a) and 11 (a). The first electrode sheet includes a first section, which may be the first anode section 215 shown in fig. 10 (a), the first section includes a first current collector layer, which may be the anode current collector layer 212 within the range of the first anode section 215 in fig. 13, and active material layers on both sides of the first current collector layer, which may be the anode active material 213 within the range of the first anode section 215 in fig. 13. In the wound electrode assembly, the anode tab 210 may be entirely located between the first separator 231 and the second separator 232, and the anode active material 213 at both sides of the first electrode sheet is directly attached to the first separator 231 and the second separator 232, respectively.

Referring to fig. 11 (a), the first electrode sheet may be a cathode sheet 220 and the second electrode sheet may be an anode sheet 210. The cathode sheet 220 may be entirely located between the first separator 231 and the second separator 232.

The first pole piece further includes a third section, in fig. 10 (a), the first pole piece is an anode piece 210, the second pole piece is a cathode piece 220, and the third section may be a third anode section 214 shown in fig. 10 (a). The third section is located at the peripheral end of the first pole piece and the third anode section 214 is located at the peripheral end of the first anode section 215. The third section includes a third current collector layer, which may be the anode current collector layer 212 within the scope of the third anode section 214 shown in fig. 10 (a) and 13. The two sides of the third current collector layer are respectively and directly attached to the first separator 231 and the second separator 232, and the second current collector layer and the first current collector layer may be connected or in an integrated structure.

In one embodiment, in fig. 11 (a), the first pole piece is a cathode piece 220, the second pole piece is an anode piece 210, and the third section may be a third cathode section 224 shown in fig. 11 (a). The third section is located at the peripheral end of the first pole piece and the third cathode section 224 is located at the peripheral end of the first cathode section 225. The third section includes a third current collector layer, which may be the cathode current collector layer 222 within the third cathode section 224 shown in fig. 11 (a) and 16. The two sides of the third current collector layer are respectively and directly attached to the first separator 231 and the second separator 232, and the second current collector layer and the first current collector layer may be connected or in an integrated structure.

The arrangement of the third cathode section 224 can ensure that the anode sheet 210 wraps the cathode sheet 220 when the first and second battery materials are cut simultaneously, and the third cathode section 224 is arranged at the peripheral tail end 243 of the electrode assembly 240 at a certain distance, so that the quality of the electrode assembly is not significantly changed even if a certain fold or turn-over occurs at the peripheral tail end 243.

In one embodiment, referring to fig. 10 (a) and 11 (a), the anode tab 210 has a third anode section 214 at the peripheral tail 243 of the electrode assembly. Referring to fig. 17, similar to the structure of the second anode section 211, the third anode section 214 also includes an anode current collector layer 212, and anode active materials 213 are not disposed on both sides of the anode current collector layer 212 so that both sides of the anode current collector layer 212 are bonded to a separator 230 in an electrode assembly 240, and the separator 230 covers both sides of the bonded anode current collector layer 212.

The arrangement of the third anode section 214 can ensure that the anode sheet 210 wraps the cathode sheet 220 when the first and second core materials are cut simultaneously, and the third anode section 214 is arranged at the peripheral tail end 243 of the electrode assembly 240 at a certain distance, so that the quality of the electrode assembly is not significantly changed even if a certain fold or turnover occurs at the peripheral tail end 243.

In one embodiment, the anode sheet 210 and/or the cathode sheet 220 are provided with an inactive layer region at the head end in the core, mainly in that the outer peripheral tail end of the outermost ring of the electrode assembly is provided with a certain inactive layer region. Referring to fig. 11 (a), in this embodiment, two layers of separator 230 clamp the cathode sheet 220 to form a first cell material, the anode sheet 210 is a second cell material, and in the outermost ring of the wound electrode assembly, the cathode sheet 220 is located at the outer ring of the anode sheet 210, in order to prevent precipitation of lithium ions, the outer peripheral end of the cathode sheet 220 of the outermost ring is provided with an inactive layer region, and the corresponding anode sheet 210 may also be provided with inactive layer regions at the outer peripheral end, respectively, a third anode section 214 and a third cathode section 224. In this embodiment, the separator 230, the anode sheet 210 and the cathode sheet 220 may be cut simultaneously at the time of winding and ending of the electrode assembly, and the cutting position may be at an inactive layer region (refer to fig. 19 and corresponding description), and at this time, the cut core material may be used as the core inner head end of the next electrode assembly, and a part of the inactive layer region may exist.

In one embodiment, referring to fig. 11 (d), the second cathode section 221 is a second end 221a at an end facing away from the winding core 242, the second anode section 211 is a first end 211a at an end facing away from the winding core 242, and the second end 221a is flat with the first end 211a, or the second end 221a is located at one side of the first end 211a along the winding direction 300, so as to form a structure that the first anode section 215 of the anode sheet 210 wraps the first cathode section 225 of the cathode sheet 220.

In one embodiment, referring to fig. 11 (a) -11 (d), the cathode tab 220 is positioned between the first separator 231 and the second separator 232, the anode tab 210 is positioned inside the winding of the second separator 232, and the length of the third cathode section 224 is greater than the sum of the peripheral circumference of the electrode assembly and the length of the third anode section 214.

Referring to fig. 11 (a), the first cell material may include a cathode sheet 220, a first separator 231, and a second separator 232, the cathode sheet 220 being positioned between the first separator 231 and the second separator 232, and the anode sheet 210 being positioned inside the winding of the second separator 232.

In the present embodiment, the winding is that the cathode tab 220 is positioned at one turn outside the anode tab 210, and the anode tab 210, the cathode tab 220, and the separator 230 are cut in one step. By providing the third cathode section 224 of the cathode sheet 220 with a length greater than the sum of the peripheral circumference of the electrode assembly and the length of the third anode section 214, the section of the anode sheet 210 having the active material is always located in the section of the cathode sheet 220 having the active material, the anode sheet 210 wraps the cathode sheet 220, and the cathode sheet 220 of the outermost ring has no active material, preventing precipitation of lithium ions.

In some possible embodiments, referring to fig. 10 (a) and 11 (a), the electrode assembly 240 includes an anode sheet 210, a cathode sheet 220, and a separator 230, the separator 230 includes a first separator 231 and a second separator 232, and the first separator 231, the anode sheet 210, the second separator 232, and the cathode sheet 220 are stacked and in a wound structure.

Referring to fig. 10 (a), the anode sheet 210 may be positioned between the first separator 231 and the second separator 232, and the cathode sheet 220 is positioned inside the winding of the second separator 232.

In one embodiment, the cathode sheet 220 may be positioned between the first separator 231 and the second separator 232, and the anode sheet 210 is positioned inside the winding of the second separator 232.

The anode tab 210, the first separator 231, the cathode tab 220, and the second separator 232 are flush at the peripheral tail 243 of the electrode assembly 240.

The electrode assembly 240 according to the present embodiment may be wound by the cell winding apparatus shown in fig. 1 to 4, or fig. 6 and 7, and the cell winding apparatus 100 includes a first winding mechanism 110, a first feeding mechanism 120, a second feeding mechanism 130, and a cutting mechanism 140.

In some possible embodiments, the first pole piece includes a first section and a fourth section, and in this embodiment, the first pole piece is taken as an anode piece 210, and the second pole piece is taken as a cathode piece 220.

In this embodiment, the anode tab 210 includes a first anode section 215, and referring to fig. 13, the first anode section 215 may be formed by stacking an anode current collector layer 212 and anode active materials 213 positioned at both sides of the anode current collector layer 212 to form an active material section of the anode tab 210.

The first pole piece further includes a fourth section, which may be a fourth anode section 216 of the anode sheet 210, as shown with reference to fig. 10 (g) and 13. The fourth section comprises a fourth current collector layer and an active material layer positioned on one side of the fourth current collector layer, wherein the other sides of the active material layer and the fourth current collector layer are respectively and directly attached to the first diaphragm and the second diaphragm, or the other sides of the active material layer and the fourth current collector layer are respectively and directly attached to the second diaphragm and the first diaphragm.

The fourth current collector layer may be the anode current collector layer 212 in the range of the fourth anode section 216 in fig. 13, and the active material layer may be the anode active material 213 in the range of the fourth anode section 216 in fig. 13. In the wound electrode assembly, the anode sheet 210 may be entirely located between the first separator 231 and the second separator 232, the anode active material 213 in the fourth anode section 216 may be bonded to the first separator 231, and the anode current collector layer 212 in the fourth anode section 216 is bonded to the second separator 232 on the side facing away from the anode active material 213; alternatively, the anode active material 213 in the fourth anode section 216 may be bonded to the second separator 232, and the anode current collector layer 212 in the fourth anode section 216 is bonded to the first separator 231 on the side facing away from the anode active material 213.

The fourth anode section 216 includes an anode current collector layer 212 and an anode active material 213 positioned at one side of the anode current collector layer 212, and the fourth anode section 216 includes the other side of the anode current collector layer 212 where no active material layer is provided, so that the side of the electrode assembly where the fourth anode section 216 where no active material layer is provided can be directly attached to the separator 230.

In one embodiment, the fourth anode section 216 may be configured to be wound around the innermost ring of the electrode assembly 240. As shown in conjunction with fig. 10 (g) and 11 (e), in the wound electrode assembly 240, the cathode active material of the cathode sheet 220 is not disposed at the winding inner side of at least a portion of the anode sheet 210 at the innermost ring, and thus the anode active material 213 may not be disposed at the portion inner side (corresponding to the lower side in fig. 22) of the anode sheet 210 to reduce the thickness of the electrode assembly 240.

In one embodiment, the fourth anode section 216 may be configured to be wound around the outermost ring of the electrode assembly 240. As shown in fig. 10 (g) and 11 (e), in the wound electrode assembly 240, the cathode active material of the cathode sheet 220 is not disposed at the wound outer side of the anode sheet 210 of the outermost ring, and thus the anode active material 213 may not be disposed at the outer side (corresponding to the upper side in fig. 22) of the anode sheet 210 to reduce the thickness of the electrode assembly 240.

Referring to fig. 10 (g), 11 (e) and 17, the fourth anode section 216 may be used to wind around the outermost ring of the electrode assembly 240, and the anode tab 210 in this embodiment includes a third anode section 214, and the fourth anode section 216 may be connected between the first anode section 215 and the third anode section 214. Alternatively, when the third anode section 214 is not disposed at the peripheral end of the anode sheet 210, the fourth anode section 216 may be directly connected to the end of the first anode section 215 near the peripheral end, and the end of the fourth anode section 216 constitutes the peripheral end.

Referring to fig. 10 (g) and 11 (e), the fourth anode segment 216 may be used to wind the innermost ring of the electrode assembly 240, in this embodiment, the second anode segment 211 is not disposed at the core front end of the anode sheet 210, the fourth anode segment 216 may be directly connected to the end of the first anode segment 215 near the core front end, and one end of the fourth anode segment 216 forms the core front end. Alternatively, when the second anode section 211 is disposed at the core front end of the anode tab 210, the fourth anode section 216 may be connected between the first anode section 215 and the second anode section 211.

In this embodiment, whether the first separator 231 and the second separator 232 sandwich the anode sheet 210 to form the first cell material or the first separator 231 and the second separator 232 sandwich the cathode sheet 220 to form the first cell material, in the wound electrode assembly, the innermost ring and the outermost ring are both the anode sheet 210 to form the structure in which the anode sheet 210 includes the cathode sheet 220. In addition, when the cathode sheet 220 containing the cathode active material is not provided on the outer side of the outermost anode sheet 210, the fourth anode section 216 described in this embodiment may be used for the outermost anode sheet 210, so as to reduce the thickness of the electrode assembly 240 and save the material of the active material; and, when the cathode sheet 220 including the cathode active material is not provided at the inner side of the innermost anode sheet 210, the fourth anode section 216 described in the present embodiment may be used for the innermost anode sheet 210 to reduce the thickness of the electrode assembly 240 and save the material for the active material.

In one embodiment, the length of the fourth section is smaller than the perimeter length of the anode sheet 210 at the outermost ring of the electrode assembly, so as to prevent the fourth section from being excessively long to cause the cathode sheet side to have no active material of the anode sheet on the basis of minimizing the thickness of the electrode assembly 240 and saving the material of the active material.

In some possible embodiments, the present application further provides a head winding method of an electrode assembly, referring to fig. 10 (a), 11 (a) and 14, including the steps of:

and M100, fixing the head end of a first electric core material in the electric core materials by a winding mechanism, wherein the first electric core material comprises a first pole piece, a first diaphragm and a second diaphragm, the first diaphragm and the second diaphragm are positioned on two sides of the first pole piece, and the first diaphragm, the first pole piece and the second diaphragm are flush at the winding head end.

The winding mechanism in this embodiment may be a winding mechanism in the winding apparatus shown in fig. 1 to 4, and the winding method in this embodiment may be at least partially the same as the winding method in the embodiment corresponding to the winding apparatus shown in fig. 1 to 4.

In this embodiment, the first core material includes a first pole piece and diaphragms 230 located on two sides of the first pole piece, where two diaphragms 230 clamp one layer of the first pole piece to jointly enter the winding mechanism.

And step M200, the first electric core material is sent to the winding mechanism at the first end of the second electric core material in a stretching state, the second electric core material comprises a second pole piece, the first pole piece is an anode piece, the second pole piece is a cathode piece, or the first pole piece is a cathode piece, and the second pole piece is an anode piece.

The first core material is pulled by the winding mechanism and is wound on the winding mechanism while being kept in a stretched state.

And step M300, winding the first battery core material and the second battery core material by the winding mechanism to form an electrode assembly, wherein the first diaphragm, the first pole piece, the second diaphragm and the second pole piece are sequentially stacked in the same circle.

When in winding, the first pole piece between the first diaphragm 231 and the second diaphragm 232 is fixed at the first end in the core by the first diaphragm 231 and the second diaphragm 232, so that the first pole piece between the first diaphragm 231 and the second diaphragm 232 has a tensile force at the first end in the core, a first electric core material is kept in a leveled state all the time in the winding process, the electrode piece is tightly attached to the diaphragm, and the electrode assembly 240 after winding forming is prevented from being folded and bent at the first end in the core, and the capacity loss of the electric core is prevented.

In one embodiment, referring to fig. 10 (a), the first electrode sheet is an anode sheet, the second electrode sheet is a cathode sheet, the first electrode material includes an anode sheet 210, and a first diaphragm 231 and a second diaphragm 232 disposed at both sides of the anode sheet 210, and the first diaphragm 231, the anode sheet 210, and the second diaphragm 232 are aligned at a winding head end.

In this embodiment, in step M200, the winding mechanism winds the first battery cell material under the tensile state, and sends the head end of the second battery cell material to the winding mechanism after the winding angle is greater than the first preset angle. And then M300, the winding mechanism winds the first cell material and the second cell material to form an electrode assembly.

After the first electric core material is wound by a first preset angle, the second feeding mechanism sends the second electric core material (cathode sheet) into the winding mechanism, the second electric core material is clamped and wound by the first electric core material and the winding mechanism, the first electric core material and the second electric core material are in a stretching state, the first electric core material and the second electric core material are prevented from being wrinkled at the first section of the feeding, and the quality of the electrode assembly is improved. Meanwhile, the structure that the electrode assembly is arranged on two sides of the anode plate and wraps the cathode plate can be guaranteed, when the battery is charged, lithium ions in the cathode plate can be completely received by the anode plate after being separated, and the lithium ions are embedded into the first active material layer, so that lithium precipitation is avoided, and safety risks are not caused.

In one embodiment, referring to fig. 10 (e), 11 (d), 12 and 13, the cathode sheet 220 wound on the winding mechanism has a second cathode section 221 at the front end, the second cathode section 221 includes a cathode current collector layer 222, and when the cathode sheet 220 (which may be a first sheet or a second sheet) is wound, both sides of the cathode current collector layer 222 are directly bonded to the separator 230, and the separator 230 covers both sides of the bonded cathode current collector layer. So that the active material layer in the anode sheet 210 can always wrap the active material layer in the cathode sheet 220 in the electrode assembly 240 after winding-forming.

In one embodiment, referring to fig. 10 (e), 11 (d), 12 and 13, the anode tab 210 wound on the winding mechanism has a second anode section 211 at the front end, the second anode section 211 includes an anode current collector layer 212, and when the anode tab 210 (which may be a first pole piece or a second pole piece) is wound, both sides of the anode current collector layer 212 are directly bonded to the separator 230, and the separator 230 covers both sides of the bonded anode current collector layer. So that the active material layer in the anode sheet 210 can always wrap the active material layer in the cathode sheet 220 in the electrode assembly 240 after winding-forming.

In one embodiment, the anode sheet 210 and/or the cathode sheet 220 are provided with an inactive layer region at the head end in the core, mainly in that the outer peripheral tail end of the outermost ring of the electrode assembly is provided with a certain inactive layer region. Referring to fig. 10 (a), the anode sheet 210 and the cathode sheet 220 are provided with inactive layer regions at the peripheral tail ends, namely, the third anode section 214 and the third cathode section 224, respectively, in this embodiment, the separator 230, the anode sheet 210 and the cathode sheet 220 may be cut simultaneously when the electrode assembly is wound and terminated, and the cutting position may be at the inactive layer region (refer to fig. 19 and the corresponding description), and at this time, the cut core material may be used as the core head end of the next electrode assembly, and there may be a part of the inactive layer region.

In one embodiment, referring to fig. 11 (c) and 11 (d), the first pole piece is a cathode piece and the second pole piece is an anode piece. The anode sheet 210 may include a portion of the second anode section 211, the second anode section 211 may be located near the head end side of the core, and both sides of the second anode section 211 are respectively bonded to the first separator 231 and the second separator 232; the cathode sheet 220 may include a portion of the second cathode section 221 as the first sheet, and the second cathode section 221 may be positioned near the head end side in the core, and both sides of the second cathode section 221 are respectively bonded to the first separator 231 and the second separator 232. In this structure, the end of the second anode section 211 connected to the first anode section 215 is a first end 211a, and the end of the second cathode section 221 connected to the first cathode section 225 is a second end 221a. The first end 211a is located inside the windings of the second end 221a.

The second end 221a may be flush with the first end 211a as shown in fig. 11 (c). Alternatively, as shown in fig. 11 (d), the second end 221a is located at one side of the first end 211a along the winding direction 300 such that both sides of the first cathode section 225 are adjacent to the first anode section 215, and the first anode section 215 of the anode sheet 210 is structured to wrap the first cathode section 225 of the cathode sheet 220.

In some possible embodiments, referring to fig. 10 (a), 10 (c), 10 (d) and 10 (e), when the electrode assembly is wound, the two-layer separator 230 clamps the first electrode sheet to form the first electrode material, the two-layer separator 230 includes the first separator 231 and the second separator 232, the second electrode sheet is the second electrode material, the first electrode sheet is the anode sheet, and the second electrode sheet is the cathode sheet. The first and second cell materials are flush at the trailing end and the first separator 231, the first pole piece, the second separator 232, and the second pole piece are flush at the peripheral trailing end of the electrode assembly.

In one embodiment, referring to fig. 11 (a), 11 (b), 11 (c) and 11 (d), when the electrode assembly is wound, the two-layer separator 230 clamps the first electrode sheet to form the first electrode material, the two-layer separator 230 includes the first separator 231 and the second separator 232, the second electrode sheet is the second electrode material, the first electrode sheet is the cathode sheet, and the second electrode sheet is the anode sheet. The first and second cell materials are flush at the trailing end and the first separator 231, the first pole piece, the second separator 232, and the second pole piece are flush at the peripheral trailing end of the electrode assembly.

It is possible that the first separator 231, the first pole piece, the second separator 232, and the second pole piece are always in a stretched state during the winding of the electrode assembly. When the electrode assembly is about to be wound, the electrode assembly is terminated in a state of keeping stretching, and the cutting mechanism synchronously cuts the first diaphragm 231, the first pole piece, the second diaphragm 232 and the second pole piece, so that the electrode assembly 240 is ensured to be always kept in a certain stretching state at the peripheral tail end, the tail area is prevented from being wrinkled and bent, and the quality of the battery cell is improved.

In some possible embodiments, the present application further provides a battery cell material, referring to fig. 18, where the battery cell material includes a first electrode sheet, and the first electrode sheet includes at least one of an anode sheet 210 and a cathode sheet 220, and this embodiment includes both the anode sheet 210 and the cathode sheet 220 as an example.

Referring to fig. 18, the cell material 200 further includes a separator 230, the separator 230 may have two layers, the anode sheet 210 may be positioned between the two layers of the separator 230, the cathode sheet 220 may be positioned at the inner side of the separator 230, and the two layers of the separator 230, the anode sheet 210 and the cathode sheet 220 may be simultaneously wound by the first winding mechanism 110 (only the first winding mechanism 110 is illustrated in this embodiment) to form the electrode assembly shown in fig. 10 (a).

In one embodiment, the cell material 200 further includes a separator 230, the separator 230 has two layers, the cathode sheet 220 may be positioned between the two layers of separator 230, the anode sheet 210 is positioned at the inner side of the separator 230, and the two layers of separator 230, the anode sheet 210 and the cathode sheet 220 may be simultaneously wound by the first winding mechanism 110 (only the first winding mechanism 110 is illustrated in this embodiment) to form the electrode assembly shown in fig. 11 (a).

Referring to fig. 18, after the first winding mechanism 110 winds to form one electrode assembly, the battery cell material is simultaneously cut at the cutting line 141 to complete winding of one electrode assembly. The other core material remaining after cutting is used to wind the next electrode assembly.

In one embodiment, referring to fig. 18, the anode sheet 210 may be formed of a stack of an intermediate anode current collector layer 212 and anode active materials 213 positioned at both sides of the anode current collector layer 212, and the cathode sheet 220 may be formed of a stack of an intermediate cathode current collector layer 222 and cathode active materials 223 positioned at both sides of the cathode current collector layer 222.

In some possible embodiments, referring to fig. 19, the cell material 200 may be composed of multiple sections of cell units, where two adjacent sections of cell units are connected by a connection structure 250. Referring to fig. 19, only the middle current collector layer is provided in a partial region of the cell material 200, and the active material is not provided at both sides of the current collector layer. The connection structure 250 may be a current collector layer provided on both sides without an active material.

Referring to fig. 19, the anode sheet 210 is provided with only the middle anode current collector layer 212 in a partial region, and anode active materials 213 are not provided on both sides of the anode current collector layer 212 in the partial region. Similarly, the cathode sheet 220 is provided with only the middle cathode current collector layer 222 in a partial region, and the cathode active material 223 is not provided on both sides of the cathode current collector layer 222 in the partial region.

After the first winding mechanism 110 is wound to form an electrode assembly, the cell material is cut along the cutting line 141 at the section where the active material is not disposed, to complete the winding of the electrode assembly. The other core material remaining after cutting is used to wind the next electrode assembly. At this time, the cutting is performed at the section where the active material is not provided and only the current collector layer is contained, the cutting line 141 divides the electrode assembly into a plurality of electrode assemblies each for winding one electrode assembly, and the portions on both sides of the cutting line 141 constitute the tail end of the electrode assembly and the winding end of the next electrode assembly.

In one embodiment, referring to fig. 19, after the cell material is cut at the cutting line 141, the cut left portion becomes the tail end of the electrode assembly that has been wound and formed, and the sections without the active material may constitute the third cathode section 224 and the third anode section 214 of the outer peripheral tail end of the electrode assembly. The right side portion after cutting becomes the second cathode section 221 and the second anode section 211 of the head end in the core of the next electrode assembly.

In some possible embodiments, referring to fig. 20, the cell material 200 may be composed of multiple sections of cell units, where two adjacent sections of cell units are connected by a connection structure 250. Referring to fig. 20, in a partial region of the cell material 200, a middle current collector layer and active materials at both sides are not provided, and two adjacent cell portions are connected by a connection structure 250. In one embodiment, referring to fig. 20, the connection structure 250 may be an adhesive tape 251, and the adhesive tape 251 adhesively connects two adjacent sections of the cell units.

After the first winding mechanism 110 is wound to form an electrode assembly, the cell material is cut along the cutting line 141 at the connection structure 250 to complete the winding of the electrode assembly. The other core material remaining after cutting is used to wind the next electrode assembly. At this time, cutting is performed at the connection structure 250, the cutting line 141 divides the electrode assembly into a plurality of battery cells each for winding one electrode assembly, and portions at both sides of the cutting line 141 constitute a take-up end of the electrode assembly and a take-up end of the next electrode assembly.

In this embodiment and other embodiments, after the tape 251 is cut, a portion of the tape is left at both ends after the cutting to form a connection film at the peripheral end of the previous electrode assembly and a connection film at the head end of the core of the next electrode assembly.

In some possible embodiments, referring to fig. 21, the cell material 200 may be composed of multiple sections of cell units, where two adjacent sections of cell units are connected by a connection structure 250. Referring to fig. 21, only the middle current collector layer is provided in a partial region of the cell material 200, and the active material is not provided at both sides of the current collector layer. The connection structure 250 may be a current collector layer, on both sides of which no active material is disposed, and an adhesive tape 251 attached to the outside, the adhesive tape 251 adhesively connecting adjacent two sections of the cell units. The current collector layer without the active material and the tape 251 together constitute a connection structure 250 to connect adjacent two sections of the cell core.

Wherein the tape bonding can provide greater extensibility to the core material. The adjacent anode sheet 210, cathode sheet 220 and separator 230 may be more closely adhered to each other when the core material is wound in a stretched state, particularly at the winding head and tail positions, so as to facilitate better winding and form an electrode assembly of a laminated structure.

Referring to fig. 21, the anode sheet 210 is provided with only the middle anode current collector layer 212 in a partial region, and anode active materials 213 are not provided on both sides of the anode current collector layer 212 in the partial region. Similarly, the cathode sheet 220 is provided with only the middle cathode current collector layer 222 in a partial region, and the cathode active material 223 is not provided on both sides of the cathode current collector layer 222 in the partial region.

After the first winding mechanism 110 is wound to form an electrode assembly, the battery cell material is cut along the cutting line 141 at the section where the active material is not disposed, and the adhesive tape 251 is also cut into two sections and attached to the cut two ends, respectively, to complete the winding of the electrode assembly. The other core material remaining after cutting is used to wind the next electrode assembly. At this time, the cutting is performed at the section where the active material is not provided and only the current collector layer is contained, the cutting line 141 divides the electrode assembly into a plurality of electrode assemblies each for winding one electrode assembly, and the portions on both sides of the cutting line 141 constitute the tail end of the electrode assembly and the winding end of the next electrode assembly.

In one embodiment, referring to fig. 21, after the core material is cut at the cutting line 141, the cut left portion becomes the tail end of the electrode assembly which has been wound and formed, and the sections without the active material may constitute the third cathode section 224 and the third anode section 214 of the outer peripheral tail end of the electrode assembly. The right side portion after cutting becomes the second cathode section 221 and the second anode section 211 of the head end in the core of the next electrode assembly.

The application divides the electric core material into a plurality of electric core portions to can connect through connection structure 250 between the electric core portions, in order to cut at connection structure 250 when electrode assembly coiling is finished, the cutting sign of being convenient for. Also, the connection structure 250 may be an adhesive tape, which can provide greater extensibility to the core material. The adjacent anode sheet 210, cathode sheet 220 and separator 230 may be more closely adhered to each other when the core material is wound in a stretched state, particularly at the winding head and tail positions, so as to facilitate better winding and form an electrode assembly of a laminated structure.

In some possible embodiments, referring to fig. 22, the cell material 200 may be composed of multiple sections of cell units, where two adjacent sections of cell units are connected by a connection structure 250. Referring to fig. 22, only the middle current collector layer is provided in a partial region of the cell material 200, and the active material is not provided at both sides of the current collector layer. The connection structure 250 may be a current collector layer provided on both sides without an active material.

In this embodiment, at least one side of the connection structure 250 is provided with a portion of active material at both front and rear ends thereof to form a stepped distribution of active material at both sides of the current collector layer.

Referring to fig. 22, the anode sheet 210 is provided with only the middle anode current collector layer 212 in a partial region, and anode active materials 213 are not provided on both sides of the anode current collector layer 212 of the partial region to constitute an inactive layer region of the anode sheet 210; further, a fourth anode section 216 is provided between the anode current collector layer 212 of the inactive layer region portion and the active material layer regions on the left and right sides (sections where the anode active material 213 is provided on both sides of the anode current collector layer 212, which may also be referred to as double-sided active material layer regions), and the fourth anode section 216 includes the anode current collector layer 212 and the anode active material 213 on one side of the anode current collector layer 212.

As shown in fig. 22, the anode active material 213 of the fourth anode section 216 located at the left side of the cutting line 141 is located at the lower side of the anode current collector layer 212, and the fourth anode section 216 of the left side of the cutting line 141 may be used to be wound around the outermost ring of the electrode assembly 240. As shown in fig. 10 (a) and 11 (a), in the wound electrode assembly 240, the cathode active material of the cathode sheet 220 is not disposed at the wound outer side of the anode sheet 210 of the outermost ring, and thus the anode active material 213 may not be disposed at the outer side (corresponding to the upper side in fig. 22) of the anode sheet 210 to reduce the thickness of the electrode assembly 240.

And, referring to fig. 22, the anode active material 213 of the fourth anode section 216 located at the right portion of the cutting line 141 may be located at the upper side of the anode current collector layer 212, and the fourth anode section 216 of the right portion of the cutting line 141 may be used to be wound at the innermost ring of the electrode assembly 240. As shown in fig. 10 (a) and 11 (a), in the wound electrode assembly 240, the cathode active material of the cathode sheet 220 is not disposed at the winding inner side of at least a portion of the anode sheet 210 at the innermost ring, and thus the anode active material 213 may not be disposed at the portion inner side (corresponding to the lower side in fig. 22) of the anode sheet 210 to reduce the thickness of the electrode assembly 240.

In one embodiment, referring to fig. 22, after the core material is cut at the cutting line 141, the cut left portion becomes the tail end of the electrode assembly which has been wound and formed, and the sections without the active material may constitute the third cathode section 224 and the third anode section 214 of the outer peripheral tail end of the electrode assembly. The right side portion after cutting becomes the second cathode section 221 and the second anode section 211 of the head end in the core of the next electrode assembly.

In some possible embodiments, referring to fig. 23, the cell material 200 may be composed of multiple sections of cell units, where two adjacent sections of cell units are connected by a connection structure 250. Referring to fig. 23, only the middle current collector layer is provided in a partial region of the cell material 200, and the active material is not provided at both sides of the current collector layer. The connection structure 250 may be a current collector layer, on both sides of which no active material is disposed, and an adhesive tape 251 attached to the outside, the adhesive tape 251 adhesively connecting adjacent two sections of the cell units. The current collector layer without the active material and the tape 251 together constitute a connection structure 250 to connect adjacent two sections of the cell core.

Referring to fig. 23, the anode sheet 210 is provided with only the middle anode current collector layer 212 in a partial region, and anode active materials 213 are not provided on both sides of the anode current collector layer 212 of the partial region to constitute an inactive layer region of the anode sheet 210; further, a fourth anode section 216 is provided between the anode current collector layer 212 of the inactive layer region portion and the active material layer regions on the left and right sides (sections where the anode active material 213 is provided on both sides of the anode current collector layer 212, which may also be referred to as double-sided active material layer regions), and the fourth anode section 216 includes the anode current collector layer 212 and the anode active material 213 on one side of the anode current collector layer 212.

As shown in fig. 23, the anode active material 213 of the fourth anode section 216 located at the left side of the cutting line 141 is located at the lower side of the anode current collector layer 212, and the fourth anode section 216 of the left side of the cutting line 141 may be used to be wound around the outermost ring of the electrode assembly 240. As shown in fig. 10 (a) and 11 (a), in the wound electrode assembly 240, the wound outer side of the anode tab 210 of the outermost ring is not provided with the first cathode section of the cathode tab 220, and thus the outer side (corresponding to the upper side in fig. 22) of the anode tab 210 may not be provided with the anode active material 213 to reduce the thickness of the electrode assembly 240.

And, referring to fig. 23, the anode active material 213 of the fourth anode section 216 located at the right portion of the cutting line 141 may be located at the upper side of the anode current collector layer 212, and the fourth anode section 216 of the right portion of the cutting line 141 may be used to be wound at the innermost ring of the electrode assembly 240. As shown in fig. 10 (a) and 11 (a), in the wound electrode assembly 240, the first cathode section of the cathode sheet 220 is not disposed at the winding inner side of at least part of the anode sheet 210 of the innermost ring, and thus the anode active material 213 may not be disposed at the part of the inner side (corresponding to the lower side in fig. 22) of the anode sheet 210 to reduce the thickness of the electrode assembly 240.

In some possible embodiments, referring to fig. 24, the cell material 200 may be composed of multiple sections of cell units, where two adjacent sections of cell units are connected by a connection structure 250. Referring to fig. 24, a fourth anode section 216 is provided at a partial region of the cell material 200, and the fourth anode section 216 includes an anode current collector layer 212 and an anode active material 213 located at one side of the anode current collector layer 212. At this time, the active material is not provided on one side, and only the active material-taking section is provided on one side, so that the single-sided active layer region of the cell material 200 is formed.

Wherein the cutting line 141 is located at the right end of the fourth anode section 216, the right side of the cutting line 141 does not have the fourth anode section 216. Also, the anode active material 213 in the fourth anode section 216 is positioned at the lower side of the anode current collector layer 212 in the present embodiment, and the fourth anode section 216 at the left side portion of the cutting line 141 may be used to be wound around the outermost ring of the electrode assembly 240. As shown in fig. 10 (a) and 11 (a), in the wound electrode assembly 240, the wound outer side of the anode tab 210 of the outermost ring is not provided with the first cathode section of the cathode tab 220, and thus the outer side (corresponding to the upper side in fig. 24) of the anode tab 210 may not be provided with the anode active material 213 to reduce the thickness of the electrode assembly 240.

After the first winding mechanism 110 is wound to form an electrode assembly, the cell material is cut along the cutting line 141 at the section where the active material is disposed at only one side, to complete the winding of the electrode assembly. The other core material remaining after cutting is used to wind the next electrode assembly. At this time, the electrode assembly is divided into a plurality of battery cells, each for winding one electrode assembly, along the cutting line 141, and portions of both sides of the cutting line 141 constitute the take-up end of the electrode assembly and the take-up end of the next electrode assembly.

In some possible embodiments, referring to fig. 25, the cell material 200 may be composed of multiple sections of cell units, where two adjacent sections of cell units are connected by a connection structure 250. Referring to fig. 24, a fourth anode section 216 is provided at a partial region of the cell material 200, and the fourth anode section 216 includes an anode current collector layer 212 and an anode active material 213 located at one side of the anode current collector layer 212. At this time, the active material is not provided on one side, and only the active material-taking section is provided on one side, so that the single-sided active layer region of the cell material 200 is formed. The connection structure 250 is provided on the side of the fourth anode segment 216 where no active material is provided, and the connection structure 250 may be an adhesive tape 251 attached to the outside, and the adhesive tape 251 adhesively connects two adjacent cell portions.

In some possible embodiments, the structures of the anode sheet 210 and the cathode sheet 220 at the cutting line 141 may employ any one of fig. 19 to 24.

For example, the anode sheet 210 is connected at the cutting line 141 by the adhesive tape 251 in fig. 20, and the cathode sheet 220 is connected at the cutting line 141 by the adhesive tape 251 and the cathode current collector layer 222 having no active material layer on both sides in fig. 21. Such combinations fall within the scope of protection defined by the present application.

In a possible embodiment, on the basis of any one of the above examples, when the winding mechanism winds up one electrode assembly, the subsequent preparation can be performed by the discharging mechanism and the profiling mechanism described in this embodiment.

Referring to fig. 15 and 25, after the winding mechanism is completed, the method further includes the steps of:

in step P100, the two sets of clamping pins 410 of the unloading mechanism 400 may penetrate into the recess 1143 of the winding mechanism, and each clamping pin 410 includes two clamping pins 411, and the two clamping pins 411 may clamp the electrode assembly 240. Referring to fig. 25, the first winding mechanism 110 is taken as an example in this embodiment.

In step P200, the electrode assembly 240 is pulled out from the winding mechanism by the clip 410, and the electrode assembly 240 is separated from the winding mechanism.

In step P300, the discharging mechanism 400 places the electrode assembly 240 on the discharging platform 500, specifically, the electrode assembly 240 is vertically placed on the discharging platform 500.

In step P400, the pre-pressing plate 600 approaches the discharging platform 500 and presses the electrode assembly 240 downward to form the electrode assembly 240 in a shape resembling a flat ring.

In one embodiment, between step P200 and step P300, the two sets of pins 410 may be moved away from each other to pre-stretch the electrode assembly 240 into an oval shape for subsequent placement on the outfeed platform 500 without rolling off the outfeed platform 500, facilitating pressing of the electrode assembly 240 by the pre-press plate 600.

The above embodiments are only for illustrating the technical solution of the present application, and are not limiting thereof; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application, and are intended to be included in the scope of the present application.

Claims

1. A method of winding a cell head for preparing an electrode assembly, comprising the steps of:

the winding mechanism is used for fixing the head end of a first electric core material fed from the first feeding mechanism and winding the first electric core material, the first feeding mechanism is positioned at the front end of the feeding of the winding mechanism and used for fixing the first electric core material, the first electric core material comprises a first pole piece, a first diaphragm and a second diaphragm which are positioned at two sides of the first pole piece, the first pole piece is an anode piece, and the first diaphragm, the first pole piece and the second diaphragm are flush at the winding head end;

when the first battery core material is in a stretching state, after the winding mechanism winds and rotates for a certain angle, the first end of a second battery core material fed by the second feeding mechanism is fed into the winding mechanism while the first battery core material is wound, the winding mechanism synchronously winds the first battery core material and the second battery core material, the second battery core material comprises a second pole piece, and the second pole piece is a cathode piece;

after forming a electric core roll body, winding mechanism stops the coiling, first electric core material with the second electric core material is under tensile state, cutting mechanism synchronous cutting first electric core material with the second electric core material, be used for making first electric core material with the second electric core material is at peripheral tail end flush and be the horizontality range upon range of, first electric core material with the second electric core material is in winding mechanism's tail end tangent plane looks coplane, first diaphragm, first pole piece, second diaphragm with the second pole piece is at the tail end of winding end flush, winding mechanism winds first electric core material with the second electric core material to form electrode assembly, first diaphragm, first pole piece, second diaphragm and second pole piece stack gradually in same circle and set up.

2. The method according to claim 1, wherein the head end of the cathode sheet wound around the winding mechanism has a second cathode section, the second cathode section includes a second cathode current collector layer, two sides of the second cathode current collector layer are respectively and directly attached to the first separator and the second separator, and the first separator and the second separator are respectively attached to two sides of the second cathode current collector layer in a covering manner.

3. The cell head winding method according to claim 2, wherein a head end of the anode tab wound on the winding mechanism has a second anode section including a second anode current collector layer, both sides of the second anode current collector layer are directly bonded to the first separator and the second separator, respectively, and the first separator and the second separator are covered and bonded to both sides of the anode current collector layer.

4. The method of claim 3, wherein the first pole piece is a cathode piece, the second pole piece is an anode piece, the second cathode section is a second end at an end facing away from the winding core, the second anode section is a first end at an end facing away from the winding core, and the second end is level with the first end, or the second end is located at a side of the first end facing away from the winding core along the winding direction.

5. An electrode assembly prepared by the cell head winding method of any one of claims 1 to 4, comprising: the first diaphragm, the first pole piece, the second diaphragm and the second pole piece are in a winding structure and are sequentially stacked in the same circle;

the first diaphragm, the second diaphragm and a first pole piece located between the first diaphragm and the second diaphragm are flush with the head end in the core of the electrode assembly, the first diaphragm, the first pole piece, the second diaphragm and the second pole piece are flush with the tail end of the periphery of the electrode assembly, any two adjacent layers at the tail end of the periphery are closely attached to form a wrinkle-free state, the first pole piece is an anode piece, and the second pole piece is a cathode piece.

6. The electrode assembly of claim 5, wherein the first pole piece comprises a first section and a second section, the second section is located at a head end in a core of the first pole piece, the first section comprises a first current collector layer and active material layers on two sides of the first current collector layer, the active material layers on two sides are respectively and directly attached to the first separator and the second separator, the second section comprises a second current collector layer, two sides of the second current collector layer are respectively and directly attached to the first separator and the second separator, and the second current collector layer and the first current collector layer are connected or are in an integrated structure.

7. The electrode assembly of claim 5, wherein the first electrode tab comprises a first section and a fourth section, the fourth section is connected to one end of the first section, the first section comprises a first current collector layer and active material layers on two sides of the first current collector layer, the active material layers on two sides are respectively and directly attached to the first separator and the second separator, the fourth section comprises a fourth current collector layer and an active material layer on one side of the fourth current collector layer, the active material layer is directly attached to the first separator and the second separator on the other side of the fourth current collector layer, or the active material layer is directly attached to the second separator and the first separator on the other side of the fourth current collector layer.

8. The electrode assembly of claim 7, wherein the first pole piece comprises a second section, the second section is located at a head end in a core of the first pole piece, the second section comprises a second current collector layer, two sides of the second current collector layer are respectively and directly attached to a first diaphragm and a second diaphragm, the fourth section is connected with one end of the first section, which is away from the second section, or the fourth section is connected with the first section and the second section.

9. The electrode assembly according to claim 7 or 8, wherein a length of the fourth section is smaller than a circumferential length of the anode sheet of the outermost ring of the electrode assembly.

10. The electrode assembly of any one of claims 5-8, wherein at least one of the first separator, the first pole piece, the second separator, and the second pole piece has a connection film attached at a head end within the core.

11. The electrode assembly of any one of claims 5-8, wherein the first separator, the first pole piece, the second separator, and the second pole piece are flush at a head end within a core of the electrode assembly.