CN218887279U

CN218887279U - Electrode assembly, battery cell, battery and electric equipment

Info

Publication number: CN218887279U
Application number: CN202222710544.XU
Authority: CN
Inventors: 曹丹; 柴志生; 谷慧
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2022-10-14
Filing date: 2022-10-14
Publication date: 2023-04-18
Anticipated expiration: 2032-10-14

Abstract

An electrode assembly, a battery cell, a battery and an electric device. An electrode assembly (10) includes: the winding structure comprises a first pole piece (11), a second pole piece (12) and a diaphragm (13) arranged between the first pole piece (11) and the second pole piece (12), wherein the first pole piece (11), the second pole piece (12) and the diaphragm (13) are wound along a winding direction (r) to form a winding structure (100); wherein a flexible spacer layer (14) is arranged between an end region (15) of at least one end of the first pole piece (11) and the second pole piece (12) in the winding direction (r) and a membrane section of the membrane (13) adjacent to the end region (15), the flexible spacer layer (14) protruding beyond the edge of the end region (15) in the circumferential direction of the wound structure (100).

Description

Electrode assembly, battery monomer, battery and consumer

Technical Field

The disclosure relates to the technical field of batteries, in particular to an electrode assembly, a battery monomer, a battery and electric equipment.

Background

The secondary battery, especially the lithium ion battery, has the advantages of high voltage, large specific energy, long cycle life, no pollution, wide working temperature range, small self-discharge and the like, is widely applied to portable electronic equipment and power equipment of large-scale new energy electric vehicles, and has great significance for solving the problems of human environmental pollution and energy crisis. With the widespread use of secondary batteries, the reliability of use of the batteries has become a concern of close attention of users.

SUMMERY OF THE UTILITY MODEL

In one aspect of the present disclosure, there is provided an electrode assembly including: the diaphragm winding device comprises a first pole piece, a second pole piece and a diaphragm arranged between the first pole piece and the second pole piece, wherein the first pole piece, the second pole piece and the diaphragm are wound along a winding direction to form a winding structure;

wherein a flexible barrier layer is arranged between an end region of at least one end of at least one of the first pole piece and the second pole piece in the winding direction and a diaphragm section adjacent to the end region on the diaphragm, and the flexible barrier layer protrudes out of the edge of the end region in the circumferential direction of the winding structure.

The flexible interlayer is arranged between the end part area and the diaphragm section adjacent to the end part area, and the flexible interlayer protrudes out of the edge of the end part area, so that concentrated shear stress formed by the steps can be dispersed through the flexible interlayer, the risk that the pole piece is broken under the action of shear force is reduced, and the use reliability of the electrode assembly is improved.

In some embodiments, one of the end region and the membrane segment is bonded to the flexible barrier and the other of the end region and the membrane segment is in slidable contact with the flexible barrier.

One of the end area and the membrane section is fixed relative to the flexible interlayer through bonding, so that the flexible interlayer can be kept in the area where the step is located, and the effective dispersion effect on the shearing stress is ensured; the other of the end region and the membrane section is in slidable contact with the flexible barrier to prevent wrinkling of the membrane caused by the end region, the membrane section and the flexible barrier all adhering together.

In some embodiments, the flexible barrier layer comprises at least one single-sided adhesive paper.

The adhesive side of the single-sided adhesive paper effects the adhesive effect and the non-adhesive side effects a sliding contact with the surface of the end region or membrane section.

In some embodiments, the septum section comprises:

a first membrane section located inside the end region;

a second membrane section located outside the end region;

wherein the flexible barrier layer comprises a first single-sided gummed paper bonded with one of the first membrane section and the second membrane section.

The first single-sided adhesive tape bonded with the diaphragm section at the side is arranged at one side of the end area, so that the dispersing effect of the end area of the pole piece on the shearing stress of the pole piece at the inner side or the outer side of the pole piece can be realized through the first single-sided adhesive tape, and burrs at the cut part of the end area can be separated from the diaphragm section at the side, so that the risk that the burrs pierce the diaphragm section to cause lap short circuit with the pole piece with the other polarity is avoided.

In some embodiments, the septum section comprises:

a first membrane section located inside the end region;

a second membrane section located outside the end region;

the flexible interlayer comprises a first single-sided gummed paper and a second single-sided gummed paper which are respectively bonded with the first diaphragm section and the second diaphragm section, and the protruding length of the first single-sided gummed paper relative to the edge of the end part area in the circumferential direction of the winding structure is the same as or different from the protruding length of the second single-sided gummed paper relative to the edge of the end part area in the circumferential direction of the winding structure.

The first single-sided gummed paper and the second single-sided gummed paper are respectively adhered to the first diaphragm section and the second diaphragm section, so that the dispersion effect of the shearing stress of the inner side and the outer side of the end part area can be realized through the first single-sided gummed paper and the second single-sided gummed paper, and burrs at the cut-off part of the end part area are effectively separated from the first diaphragm section and the second diaphragm section, so that the risk of lap joint and short circuit of the burrs with the other polarity pole piece due to the fact that the burrs pierce the diaphragm sections is reduced. In addition, the projecting length of the first single-sided adhesive tape in the circumferential direction of the winding structure with respect to the edge of the end portion region is made the same as the projecting length of the second single-sided adhesive tape in the circumferential direction of the winding structure with respect to the edge of the end portion region, whereby the dispersion action of the shear stress can be made more uniform between the inside and the outside of the end portion region.

The protruding length of the first single-sided gummed paper relative to the edge of the end area in the circumferential direction of the winding structure is different from the protruding length of the second single-sided gummed paper relative to the edge of the end area in the circumferential direction of the winding structure, so that the overhanging part of the first single-sided gummed paper, the end area and the overhanging part of the second single-sided gummed paper can form a step with gradually changed thickness, the step can effectively reduce shearing stress, and the risk of the pole piece being broken under the action of shearing force is effectively reduced by matching the flexibility of the first single-sided gummed paper and the second single-sided gummed paper.

In some embodiments, the flexible barrier layer comprises a first single-sided adhesive paper that is adhered by folding to both the inside and outside surfaces of the end region.

Two opposite bonding surfaces and two opposite non-bonding surfaces are formed by folding the first single-sided gummed paper, the two bonding surfaces are respectively bonded with the inner side surface and the outer side surface of the end part area, the two non-bonding surfaces are used for realizing sliding contact with the diaphragm sections on the inner side and the outer side of the end part area, the cutting part of the end part area is sealed by the folding area, and the risk of lap joint short circuit caused by the fact that burrs on the cutting part pierce or scratch the diaphragm is avoided.

In some embodiments, the flexible barrier layer comprises a first single-sided gummed paper and a second single-sided gummed paper respectively adhered to the inner side surface and the outer side surface of the end region, and the protruding length of the first single-sided gummed paper relative to the edge of the end region in the circumferential direction of the winding structure is the same as or different from the protruding length of the second single-sided gummed paper relative to the edge of the end region in the circumferential direction of the winding structure.

The inner side surface and the outer side surface of the end part area are bonded through the first single-sided gummed paper and the second single-sided gummed paper with opposite bonding surfaces, and the cut part of the end part area is sealed through mutual bonding of the protruding sections with the same or different protruding lengths of the first single-sided gummed paper and the second single-sided gummed paper relative to the edge of the end part area, so that the risk of lap short circuit caused by the fact that burrs of the cut part pierce or scratch a diaphragm is avoided. Moreover, the process difficulty of the bonding mode of the first single-sided gummed paper and the second single-sided gummed paper is relatively small.

In some embodiments, the first pole piece is a negative pole piece and the second pole piece is a positive pole piece.

In some embodiments, in the winding structure, the pole piece layer where the first end of the first pole piece is located in the winding direction is located on the outer side of the pole piece layer where the second end of the second pole piece is located in the winding direction, the first end protrudes relative to the second end in the circumferential direction of the winding structure, a flexible interlayer is arranged between the end region of the pole piece layer where the first end is located and the diaphragm section adjacent to the end region of the pole piece layer where the first end is located on the diaphragm, and a flexible interlayer is arranged between the end region of the pole piece layer where the second end is located and the diaphragm section adjacent to the end region of the pole piece layer where the second end is located on the diaphragm.

The pole piece layer where the first end of the first pole piece is located on the outer side of the pole piece layer where the second end of the second pole piece is located, the first end protrudes relative to the second end in the circumferential direction, the wrapping effect of the outermost negative pole piece on the outermost positive pole piece can be achieved, the negative pole piece is ensured to have a sufficient lithium embedding space, and the possibility of lithium precipitation of the outermost negative pole piece is reduced. Under the structure, the flexible interlayers are arranged at the first tail end and the second tail end, so that the shearing stress of the steps formed at the first tail end and the second tail end on the pole piece can be dispersed in the circulation process of the electrode assembly, the risk that the pole piece is broken under the action of the shearing force is reduced, and the use reliability of the electrode assembly is improved; and for the second end, the flexible interlayer can separate burrs at the cut part of the end area of the flexible interlayer from the diaphragm so as to prevent the burrs from piercing the diaphragm and being in lap joint with the negative pole piece to be short-circuited.

In some embodiments, in the winding structure, the pole piece layer at which the first start end of the first pole piece in the winding direction is located inside the pole piece layer at which the second start end of the second pole piece in the winding direction is located, and the first start end protrudes in the circumferential direction of the winding structure relative to the second start end, and a flexible barrier layer is arranged between an end region of the pole piece layer at which the second start end is located and a diaphragm segment on the diaphragm adjacent to the end region of the pole piece layer at which the second start end is located.

The pole piece layer where the first starting end of the first pole piece is located on the inner side of the pole piece layer where the second starting end of the second pole piece is located, and the first starting end protrudes relative to the second starting end along the circumferential direction, so that the negative pole piece can be ensured to have a sufficient lithium embedding space, and the possibility of lithium precipitation of the innermost negative pole piece is reduced. Under the structure, the flexible interlayer is arranged in the end part area of the pole piece layer where the second starting end is located, so that the shearing stress of the step formed at the second starting end to the pole piece can be dispersed in the circulation process of the electrode assembly, the risk that the pole piece is broken under the action of the shearing force is reduced, and the use reliability of the electrode assembly is further improved. Because the winding of the center of the electrode assembly is loose, the negative pole piece can be wound for several circles in an empty mode, so that a flexible interlayer does not need to be arranged at the first starting end, and the situation that burrs at the cut-off part of the end part area of the first starting end pierce through the diaphragm to be in lap joint with the positive pole piece and short circuit is avoided.

In some embodiments, at least one of the first and second pole pieces comprises:

a current collector substrate;

an active material layer provided at least on a surface of the current collector substrate on a side adjacent to the separator;

wherein, in the winding direction, a surface portion of at least one end of the current collector substrate corresponding to the end region is not covered with the active material layer.

The active substance layer is not covered on the part, corresponding to the end part area, of the current collector substrate of the pole piece, and the step height of the end part area can be reduced no matter whether the flexible interlayer is arranged in the end part area, so that the shearing stress caused by the steps when the electrode assembly is circularly expanded is reduced, the risk that the pole piece is broken under the action of the shearing force is reduced, and the use reliability of the electrode assembly is improved.

In some embodiments, the coiled structure is a cylindrical coiled structure, and the length L of the flexible barrier layer in the coiling direction satisfies:

0.03π*D≤L≤0.25π*D；

wherein D is the diameter of the cylindrical winding structure.

By enabling the length L to be larger than or equal to 0.03 pi times of the diameter D and smaller than or equal to 0.25 pi times of the diameter D, the flexible interlayer can be reliably bonded and fixed with the pole piece or the diaphragm, the setting difficulty of the flexible interlayer is reduced, the blocking of the flexible interlayer on a lithium ion diffusion channel can be reduced, and the influence of the flexible interlayer on the performance of an electrode assembly is reduced.

In some embodiments, the length L satisfies: l is not less than 0.07 pi and D is not more than 0.13 pi and D.

By enabling the length L to be larger than or equal to 0.07 pi times of the diameter D and smaller than or equal to 0.13 pi times of the diameter D, the bonding and fixing between the flexible interlayer and the pole piece or the diaphragm can be more reliable, the setting difficulty of the flexible interlayer is further reduced, the blocking of the flexible interlayer on a lithium ion diffusion channel can be effectively reduced, and the influence of the flexible interlayer on the performance of the electrode assembly is reduced.

In some embodiments, the coiled structure is a cylindrical coiled structure, and the width W of the flexible barrier layer in the direction of extension of the axis of the cylindrical coiled structure satisfies:

W1≤W≤H；

wherein W1 is the width of the end region in the direction of extension of the axis of the cylindrical winding structure, and H is the height of the cylindrical winding structure in the direction of extension of the axis of the cylindrical winding structure.

By enabling the width W of the flexible interlayer to satisfy that W1 is not less than W and not more than H, the risk of breakage of the pole piece caused by shear stress during cyclic expansion of the electrode assembly can be reduced, and adverse effects on subsequent processes are reduced.

In some embodiments, the protruding length L1 of the flexible barrier layer in the circumferential direction of the rolled structure relative to the edge of the end region satisfies:

(1/4)*L≤L1≤(3/4)*L；

wherein L is the length of the flexible barrier layer in the winding direction.

By enabling the protrusion length L1 to be larger than or equal to 1/4 times of L and smaller than or equal to 3/4 times of L, the flexible interlayer can effectively overcome the influence of fluctuation of the actual bonding position of the flexible interlayer, and the dispersion effect of the flexible interlayer on the shearing stress is ensured.

In some embodiments, the protrusion length L1 satisfies: l is more than or equal to (1/3) and less than or equal to L1 and less than or equal to (2/3) L.

By enabling the protrusion length L1 to be larger than or equal to 1/3 times of L and smaller than or equal to 2/3 times of L, the influence of fluctuation of the actual bonding position of the flexible interlayer can be effectively overcome by the flexible interlayer, and the dispersion effect of the flexible interlayer on the shearing stress is further ensured.

In some embodiments, the thickness T of the flexible barrier layer satisfies:

0.07*t≤T≤0.8*t；

and t is the thickness of the pole piece which is arranged in the first pole piece and the second pole piece and is adjacent to the flexible interlayer after the electrode assembly is charged and discharged for the first time.

By enabling the thickness T of the flexible interlayer to be more than or equal to 0.07 time of the thickness T of the pole piece and less than or equal to 0.8 time of the thickness T of the pole piece, the shearing stress at the step can be effectively dispersed when the electrode assembly is circularly expanded, and the risk of fracture of the pole piece due to overlarge shearing stress is reduced.

In some embodiments, the thickness T satisfies: t is more than or equal to 0.2 and less than or equal to 0.5.

By enabling the thickness T of the flexible interlayer to be larger than or equal to 0.2 times of the thickness T of the pole piece and smaller than or equal to 0.5 times of the thickness T of the pole piece, the shearing stress at the step can be effectively dispersed when the electrode assembly is in cyclic expansion, and the risk of breakage of the pole piece due to overlarge shearing stress is further reduced.

In some embodiments, the pole piece layer where the first end of the first pole piece in the winding direction is located and the pole piece layer where the second end of the second pole piece in the winding direction is located are both located on the inner side of the separator layer where the third end of the separator in the winding direction is located, the third end protrudes in the circumferential direction of the winding structure relative to the first end and the second end, and the third end is fixed on the electrode assembly through a third single-sided adhesive tape in an adhering manner.

The third single-sided adhesive paper is arranged at the third tail end of the diaphragm to realize bonding fixation, the diaphragm ending fixation effect can be realized, and the wound electrode assembly is ensured not to be loose.

In some embodiments, the winding structure is a cylindrical winding structure, and the length L2 of the third single-sided offset paper in the winding direction satisfies:

0.07π*D≤L2≤1.5π*D；

wherein D is the diameter of the cylindrical winding structure.

By setting the length L2 to be not less than 0.07 pi times the diameter D and not more than 1.5 pi times the diameter D, the electrode assembly can be firmly bonded without loosening, and can be easily inserted into the case of the battery cell.

In some embodiments, length L2 satisfies: l2 is not less than 0.25 pi x D and not more than 1.05 pi x D.

By making the length L2 greater than or equal to 0.25 pi times the diameter D and less than or equal to 1.05 pi times the diameter D, the electrode assembly can be bonded more securely without loosening, and the electrode assembly can be further facilitated to enter the case of the battery cell.

In some embodiments, length L2 satisfies: pi x D < L2 is less than or equal to 1.05 pi x D.

By enabling the length L2 to be larger than the diameter D which is pi times and smaller than or equal to 1.05 pi times, the third single-sided gummed paper can be overlapped a little while being bonded and fixed with the tail end of the diaphragm, so that the number of steps formed by the end part of the third single-sided gummed paper on the diaphragm is reduced, the action of the steps formed by the third single-sided gummed paper on the shearing stress of the pole piece when the electrode assembly is expanded circularly is reduced, and the risk of the pole piece breaking under the action of the shearing stress is reduced.

In some embodiments, the winding structure is a cylindrical winding structure, the number of the third single-sided gummed papers is two, and two third single-sided gummed papers are arranged at intervals along the extension direction of the axis of the cylindrical winding structure.

Through setting up two third single face adhesive tape along the extending direction interval arrangement of axis, can avoid the third single face adhesive tape to form too big constraint power to electrode assembly when satisfying the fixed requirement of bonding to reduce the percentage elongation of the mass flow body substrate of electrode assembly, and still reduced the adhesive tape quantity of third single face adhesive tape.

In some embodiments, in the extending direction of the axis of the cylindrical winding structure, the minimum distance from the third one-sided gummed paper adjacent to the first end of the cylindrical winding structure in the two third one-sided gummed papers to the first end is h1, the width from the third one-sided gummed paper adjacent to the first end of the cylindrical winding structure in the two third one-sided gummed papers is W2, the minimum distance from the third one-sided gummed paper adjacent to the second end of the cylindrical winding structure in the two third one-sided gummed papers to the second end is h2, the width from the third one-sided gummed paper adjacent to the second end of the cylindrical winding structure in the two third one-sided gummed papers is W3, and h1, W2, h2 and W3 satisfy:

0≤h1≤0.07*H，0≤h2≤0.07*H，0.05*H≤W2≤0.12*H，0.05*H≤W3≤0.12*H；

wherein H is the height of the cylindrical winding structure in the direction of extension of the axis of the cylindrical winding structure.

The third single-sided adhesive tape can be mainly pasted on the active material coating thinning area at two sides of the pole piece by enabling h1 and h2 to satisfy 0 h 1-0.07 h,0 h 2-0.07 h, and W2 and W3 to satisfy 0.05 h-W2-0.12 h, and 0.05 h-0.12 h, so that the third single-sided adhesive tape with a larger thickness range can be applicable, and the electrode assembly can not be easily influenced to enter the shell of the battery monomer even if the third single-sided adhesive tape with a relatively thick thickness is adopted.

In some embodiments, the thickness T1 of the third single-sided offset paper satisfies: t1 is more than or equal to 5 mu m and less than or equal to 120 mu m.

When the minimum distances h1 and h2 and the widths W2 and W3 meet the proper value ranges, the thickness T1 of the third single-sided adhesive paper meets the condition that T1 is not less than 5 microns and not more than T1 and not more than 120 microns, so that the third single-sided adhesive paper has proper tensile strength, the risk that the third single-sided adhesive paper is broken under the action of tensile force when the electrode assembly circularly expands is reduced, the overall outer contour size of the electrode assembly bonded with the third single-sided adhesive paper is more proper, and the electrode assembly is prevented from interfering with the shell when entering the shell.

In some embodiments, in the extending direction of the axis of the cylindrical winding structure, the minimum distance from the third one-sided gummed paper adjacent to the first end of the cylindrical winding structure in the two third one-sided gummed papers to the first end is h1, the width from the third one-sided gummed paper adjacent to the first end of the cylindrical winding structure in the two third one-sided gummed papers is W2, the minimum distance from the third one-sided gummed paper adjacent to the second end of the cylindrical winding structure in the two third one-sided gummed papers to the second end is h2, the width from the third one-sided gummed paper adjacent to the second end of the cylindrical winding structure in the two third one-sided gummed papers is W3, and h1, W1, h2 and W2 satisfy:

0.07*H≤h1≤0.25*H，0.07*H≤h2≤0.25*H，0.05*H≤W2≤0.23*H，0.05*H≤W3≤0.23*H；

wherein H is the height of the cylindrical wound structure in the direction of extension of the axis of the cylindrical wound structure.

By making h1 and h2 satisfy 0.07 x H ≤ h1 ≤ 0.25 x H,0.07 x H ≤ h2 ≤ 0.25 x H, and making W2 and W3 satisfy 0.05 x H ≤ W2 ≤ 0.23 x H,0.05 x H ≤ W3 ≤ 0.23 x H, the active material on both sides of the third single-sided gummed paper pasting pole piece can be pasted on the area with normal thickness coated with active material, thereby applying the third single-sided gummed paper with relatively small thickness range, and increasing the width of the third single-sided gummed paper to improve the firmness degree of the pasting, so that the electrode assembly is not easy to loosen.

In some embodiments, the thickness T1 of the third single-sided offset paper satisfies: t1 is more than or equal to 5 mu m and less than or equal to 60 mu m.

When the minimum distances h1 and h2 and the widths W2 and W3 meet the proper value ranges, the thickness T1 of the third single-sided adhesive paper meets the condition that T1 is more than or equal to 5 microns and less than or equal to 60 microns, so that the third single-sided adhesive paper has proper tensile strength, the risk of fracture of the third single-sided adhesive paper under the action of tensile force when the electrode assembly circularly expands is reduced, the overall outer contour size of the electrode assembly bonded with the third single-sided adhesive paper is more proper, and the electrode assembly is prevented from interfering with the shell when entering the shell.

In one aspect of the present disclosure, there is provided a battery cell including: the foregoing electrode assembly. The battery cell using the electrode assembly described above can achieve superior reliability in use.

In one aspect of the present disclosure, there is provided a battery including: the battery cell is described above. The battery adopting the battery monomer can realize better use reliability.

In one aspect of the present disclosure, there is provided an electric device including: the foregoing battery. The electric equipment adopting the battery can realize better use reliability.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required to be used in the embodiments of the present disclosure will be briefly described below, it is obvious that the drawings described below are only some embodiments of the present disclosure, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

The present disclosure may be more clearly understood from the following detailed description, taken with reference to the accompanying drawings, in which:

FIG. 1 is a schematic structural diagram of some embodiments of a powered device according to the present disclosure;

fig. 2A is an exploded schematic view of some embodiments of a battery according to the present disclosure;

fig. 2B is an exploded schematic view of some embodiments of a battery cell according to the present disclosure;

fig. 3 is a schematic view of a winding structure according to some embodiments of an electrode assembly of the present disclosure;

FIGS. 4A and 4B are schematic views of the forces applied to adjacent pole piece layers during cyclic expansion of the electrode assembly in the end regions of the pole pieces without and with the flexible barrier layer, respectively;

FIGS. 5A-5G are schematic views of the flexible barrier layer of some embodiments of the electrode assemblies of the present disclosure;

fig. 6A is a schematic view of a portion of an electrode assembly of the present disclosure in an expanded state at an end region in some embodiments;

FIG. 6B is a schematic size diagram of FIG. 6A;

FIG. 6C is a schematic view of the AA cross-section of FIG. 6A;

fig. 7A is a schematic structural view of some embodiments of an electrode assembly of the present disclosure;

FIG. 7B is a schematic size diagram of FIG. 7A;

fig. 7C is a schematic cross-sectional view of the third single-sided adhesive paper of fig. 7A adhered to the third end of the membrane.

It should be understood that the dimensions of the various parts shown in the figures are not drawn to scale. Further, the same or similar reference numerals denote the same or similar components.

Description of reference numerals:

10: an electrode assembly; 10A: a current collector substrate; 10B: an active material layer; 100: a winding structure; 100A: a first end; 100B: a second end; 11: a first pole piece; 11A: a first start end; 11B: a first end; 12: a second pole piece; 12A: a second starting end; 12B: a second end; 13: a diaphragm; 131: a first membrane section; 132: a second membrane section; 133: a third end; 14: a flexible barrier layer; 14A: bonding surface; 14B: a non-adhesive surface; 141: a first single-sided gummed paper; 142: a second single-sided gummed paper; 15: an end region; 16: third single-sided gummed paper;

20: a battery cell; 21: a housing; 22: an end cap; 23: a current collecting plate;

30: a battery; 31: a box body; 32: box cover

40: a vehicle.

Detailed Description

Embodiments of the present disclosure are described in further detail below with reference to the drawings and examples. The following detailed description of the embodiments and the accompanying drawings are intended to illustrate the principles of the disclosure, but are not intended to limit the scope of the disclosure, i.e., the disclosure is not limited to the described embodiments.

In the description of the present disclosure, it is to be noted that, unless otherwise specified, "a plurality" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," and the like, indicate an orientation or positional relationship merely to facilitate the description of the disclosure and to simplify the description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be taken as limiting the disclosure. Furthermore, the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. "vertical" is not strictly vertical, but is within the tolerance of the error. "parallel" is not strictly parallel but within the tolerance of the error.

The directional terms used in the following description are intended to be illustrative in all directions, and are not intended to limit the present disclosure to specific configurations. In the description of the present disclosure, it should also be noted that, unless otherwise explicitly stated or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as being fixedly connected, detachably connected, or integrally connected; may be directly connected or indirectly connected through an intermediate. The specific meaning of the above terms in the present disclosure can be understood as appropriate to one of ordinary skill in the art.

Some embodiments of the invention are described in detail below with reference to the accompanying drawings. Features in the embodiments described below may be combined with each other without conflict.

In the winding structure of the electrode assembly, the electrode sheet layer adjacent to the beginning or end of the electrode sheet in the winding direction forms a step, and such a step may form a shear stress to the adjacent electrode sheet layer when the electrode assembly is cyclically expanded, and if such a shear stress is large, it may cause the electrode sheet to be broken by force at a position corresponding to the step, thereby causing the failure of the electrode assembly and affecting the reliability of the use of the electrode assembly.

In view of this, the present disclosure provides an electrode assembly, a battery cell, a battery and an electric device, which can improve the reliability of the battery.

The electrode assembly of the disclosed embodiment may be applicable to various types of battery cells. The battery cell may include a lithium ion secondary battery, a lithium ion primary battery, a lithium sulfur battery, a sodium lithium ion battery, a sodium ion battery, a magnesium ion battery, or the like, which is not limited in the embodiments of the present disclosure. The battery cell may be a cylinder, a flat body, a rectangular parallelepiped, or other shapes, which is not limited in the embodiments of the present application. The battery cell is generally divided into a cylindrical battery cell, a square battery cell and a soft package battery cell in a packaging manner, which is not limited in the embodiment of the present application.

The battery cell of the embodiment of the disclosure is applicable to various batteries. The battery may be used for supplying power to electric devices such as a vehicle, for example, to provide a power source for steering or a power source for driving the vehicle. The battery may include a case for providing an accommodating space for the battery module, and the battery module mounted in the case. The housing may be made of metal. The battery module may include a plurality of battery cells connected in series, parallel, or series-parallel. The battery cell is the smallest unit constituting the battery. The battery cell includes an electrode assembly capable of electrochemical reaction.

The battery of the embodiment of the disclosure can be applied to various electric devices using the battery. The electric devices may be mobile phones, portable devices, notebook computers, battery cars, electric automobiles, ships, spacecrafts, electric toys, electric tools, and the like, for example, the spacecrafts include airplanes, rockets, spacecrafts, and the like, the electric toys include stationary or mobile electric toys, for example, game consoles, electric automobile toys, electric ship toys, electric airplane toys, and the like, and the electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and electric tools for railways, for example, electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, electric drill impacts, concrete vibrators, and electric planers. The embodiment of the present disclosure does not particularly limit the above-described electric devices.

Fig. 1 is a schematic structural diagram of some embodiments of a powered device according to the present disclosure. For convenience, the electric equipment is taken as an example of a vehicle. The vehicle 40 may be a fuel automobile, a gas automobile, or a new energy automobile, and the new energy automobile may be a pure electric automobile or a hybrid electric automobile, etc. The battery 30 may be provided at the bottom or the head or tail of the vehicle 40.

The battery 30 may be used to power the vehicle 40, for example, the battery 30 may be used as an operating power source for the vehicle 40 for circuitry of the vehicle 40, such as for power requirements for operation during start-up, navigation, and operation of the vehicle 40. The battery 30 may be used not only as an operation power source of the vehicle 40 but also as a driving power source of the vehicle 40 instead of or in part of fuel or natural gas to provide driving force for the vehicle 40.

Fig. 2A is an exploded schematic view of some embodiments of a battery according to the present disclosure. Fig. 2B is an exploded schematic view of some embodiments of a battery cell according to the present disclosure. Referring to fig. 2A, in some embodiments, the battery 30 includes a case 31, a case lid 32, and one or more battery cells 20 disposed in the case 31. The case 31 may accommodate the battery cell 20, provide functions such as cooling, sealing, and impact prevention to the battery cell 20, and prevent liquid or other foreign matter from adversely affecting the charging and discharging or safety of the battery cell 20. A cover 32 may cover an end of the case 31 to close the case 31. The individual cells 20 are electrically connected, such as in series, parallel, or series-parallel, to achieve desired electrical performance parameters of the battery 30. The plurality of battery cells 10 are arranged in a row, and one or more rows of battery cells 20 may be arranged in the case as needed.

In some embodiments, the battery cells 20 of the battery 30 may be arranged along at least one of a length direction and a width direction of the case. At least one row or column of the battery cells 20 may be provided according to actual needs. One or more layers of the battery cells 20 may be provided in the height direction of the battery 30 as needed.

In some embodiments, a plurality of battery cells 20 may be connected in series or in parallel or in series-parallel to form a battery module, and then a plurality of battery modules are connected in series or in parallel or in series-parallel to form a whole, and are accommodated in the box 31. In other embodiments, all the battery cells 20 are directly connected in series or in parallel or in series-parallel, and the whole of all the battery cells 20 is accommodated in the box body. The electrode terminals of the battery cells 20 may be electrically connected to the adjacent battery cells 20 through bus bars (buss bars).

Referring to fig. 2B, in some embodiments, the battery cell 20 may include a case 21, an end cap 22, and the electrode assembly 10. The case 21 has a cavity for receiving the electrode assembly, and at least one end of the case 21 may be configured to be open for disposing the end cap 22. The battery cell 20 includes an electrolyte in addition to the electrode assembly, the end cap 22, and the case 21. The battery cell 20 may also include a current collecting disc 23. The collector plate 23 is located on the electrode tab of the electrode assembly and the electrode post diameter on the end cap, and can be fixedly connected with the flattened electrode tab by welding.

The cavity of the case 21 may be used to receive the electrode assembly 10 and may receive an electrolyte. The end opening of the case 21 is used for the electrode assembly 10 to enter the cavity through the end opening when the battery cell is mounted. The shape of the case 21 may be determined according to the shape of one or more electrode assemblies 10 received in the cavity, for example, the case 21 may have a shape of a hollow rectangular parallelepiped or a hollow cube or a hollow cylinder. The housing 21 may be made of metal (e.g., aluminum alloy, etc.) or non-metallic material (plastic) having certain hardness and strength.

The end cap 22 is provided at the end opening of the case 21 to close the end opening, and forms a hermetic chamber accommodating the electrode assembly 10 with the case 21. The end cap 22 may be made of a metal (e.g., aluminum alloy, etc.) or a non-metallic material (plastic) having a certain hardness and strength. The end cap 22 and the housing 21 may be fixedly connected by welding, bonding, or connecting members. Some functional components, such as a terminal post for electrical connection with the electrode assembly, a fluid injection mechanism, a pressure relief mechanism, etc., may be disposed on the end cap 22.

Fig. 3 is a schematic view of a winding structure according to some embodiments of the electrode assembly of the present disclosure.

Fig. 4A and 4B are schematic views of the forces acting on adjacent pole piece layers during cyclic expansion of the electrode assembly in the end regions of the pole pieces without and with the flexible barrier layer, respectively. Referring to fig. 3 and 4B, the present disclosure provides an electrode assembly 10 including: the winding structure comprises a first pole piece 11, a second pole piece 12 and a diaphragm 13 arranged between the first pole piece 11 and the second pole piece 12, wherein the first pole piece 11, the second pole piece 12 and the diaphragm 13 are wound along a winding direction r to form a winding structure 100.

The first pole piece 11 and the second pole piece 12 have opposite polarities. In some embodiments, the first pole piece 11 is a negative pole piece, and the second pole piece 12 is a positive pole piece. In other embodiments, the first pole piece 11 is a positive pole piece, and the second pole piece 12 is a negative pole piece. Operation of the electrode assembly 10 is accomplished by movement of internal metal ions between the positive and negative electrode plates.

The positive pole piece comprises a positive current collector substrate and a positive active material layer. The positive electrode tab is connected or formed on the positive electrode current collector substrate. Taking a lithium ion battery as an example, the material of the positive electrode current collector substrate may be aluminum, and the positive electrode active material may be a lithiation material capable of providing lithium ions, such as lithium cobaltate, lithium iron phosphate, ternary lithium, or lithium manganate. In the case of bonding the positive electrode current collector substrate and the positive electrode active material layer using a bonding material, the bonding material may be PVDF (Polyvinylidene Fluoride) or the like.

The negative electrode plate comprises a negative electrode current collector substrate and a negative electrode active material layer. The negative pole tab is connected and activated on the negative pole current collector substrate. Taking a lithium ion battery as an example, the material of the negative current collector substrate may be copper, and the negative active material may be a material capable of storing lithium ions, such as graphite, silicon, lithium titanate, and the like. In the case of bonding the negative electrode current collector substrate and the negative electrode active material layer with a binder, the binder may be carboxymethyl cellulose, epoxy resin, styrene-butadiene rubber, or the like.

The material of the diaphragm may be PP (polypropylene) or PE (polyethylene). The electrolyte comprises electrolyte and solvent, wherein the electrolyte is organic metal salt, inorganic salt and the like, and can provide metal ions shuttling between the positive pole piece and the negative pole piece. In order to ensure enough overcurrent capacity, the tabs corresponding to each layer of positive pole piece of the winding structure can be flattened and then welded with the current collecting disc or the positive pole posts on the end cover, and the tabs corresponding to each layer of negative pole piece can be flattened and then welded with the current collecting disc or the negative pole posts on the end cover.

In fig. 3, the first pole piece 11 has a first start 11A and a first end 11B in the winding direction r, and the second pole piece 12 has a second start 12A and a second end 12B in the winding direction r. In the winding structure 100, one separator 13, the first pole piece 11, the other separator 13, and the second pole piece 12 are sequentially stacked and then wound in the winding direction r, and both separators 13 may be longer than the first pole piece 11 and the second pole piece 12 in the winding direction r, and accordingly, the innermost side of the winding structure 100 may be wound up from both separators 13 first, and the third ends 133 of both separators 13 may be wound up on the outermost side of the winding structure 100.

Referring to fig. 3 and 4B, a flexible barrier layer 14 is provided between an end region 15 of at least one end of the first pole piece 11 and the second pole piece 12 in the winding direction r and a membrane segment of the membrane 13 adjacent to the end region 15, wherein the flexible barrier layer 14 protrudes beyond an edge of the end region 15 in the circumferential direction of the wound structure 100.

In fig. 3, the end region 15 may be at least one of the end region 15 of the pole piece layer where the first start end 11A of the first pole piece 11 is located, the end region 15 of the pole piece layer where the first end 11B of the first pole piece 11 is located, the end region 15 of the pole piece layer where the second start end 12A of the second pole piece 12 is located, and the end region 15 of the pole piece layer where the second end 12B of the second pole piece 12 is located. For embodiments where a pole piece of a certain length is formed by cutting, the edge of the end region 15 is the cutting location of the pole piece.

The membrane segment of the membrane 13 adjacent to said end region 15 may be a membrane segment of the membrane 13 inside or outside the end region 15 and adjacent to the end region. The inner side and the outer side are relative to the winding structure 100, and the side close to the center of the winding structure 100 is the inner side, and the side far from the center of the winding structure 100 is the outer side.

The circumferential direction of the winding structure 100 may be the winding direction r or may be the reverse direction of the winding direction r. Depending on the position of the end zone 15, the direction in which the flexible barrier layer 14 bulges relative to the edge of said end zone 15 may differ. For example, if the flexible barrier layer 14 is provided at the end region 15 of the first start 11A or the second start 12B, the flexible barrier layer 14 protrudes in the opposite direction of the winding direction r with respect to the edge of the end region 15; when the flexible barrier layer 14 is provided in the end region 15 of the pole piece layer where the first end 11B is located or the pole piece layer where the second end 12B is located, the flexible barrier layer 14 protrudes in the winding direction r with respect to the edge of the end region 15.

The diaphragm segment of the diaphragm 13 adjacent to the end region 15 may be a diaphragm segment in which the diaphragm 13 is located inside the end region 15 and adjacent to the end region 15, or a diaphragm segment in which the diaphragm 13 is located outside the end region 15 and adjacent to the end region 15. Accordingly, the flexible barrier 14 may be provided between the end region 15 and the inner membrane section, or between the end region 15 and the outer membrane section.

For convenience of illustration, the position of the second end 12B of the second pole piece 12 is selected. In fig. 4A, the flexible barrier 14 is not provided between the end region 15 of the pole piece layer where the second end 12B is located and the diaphragm section inside it, and in fig. 4B, the flexible barrier 14 is provided between the end region 15 of the pole piece layer where the second end 12B is located and the diaphragm section inside it.

As can be seen from fig. 4A and 4B, in the winding structure 100, the end region 15 of the pole piece layer where the second end 12B of the second pole piece 12 in the winding direction r is located forms a step with the pole piece layer of the first pole piece 11 inside the end, and such a step may form a shear stress to the inside pole piece layer when the electrode assembly 10 is cyclically expanded. The step edge in fig. 4A creates a relatively concentrated shear stress F when the inside pole piece layer is cyclically expanded. Since the shear stress F is relatively concentrated, the inner pole piece layer is easily broken by the shear stress.

The flexible barrier 14 of FIG. 4B may deform under the application of an external force, such that the relatively concentrated shear stress created by the steps may be dispersed through the flexible barrier 14, and it can be seen that the shear stress F 'is dispersed to a greater extent, and accordingly the shear stress F' is significantly less than the shear stress F without the flexible barrier 14. This reduces the risk of the pole pieces breaking under the action of shear forces and thus improves the reliability of use of the electrode assembly 10.

For embodiments in which the pole piece is cut to length, the edge of the end region 15 is the cut location of the pole piece. The flexible barrier layer 14 separates the burrs at the cut-off portion of the end region 15 from the separator 13 to prevent the burrs from piercing the separator 13 and shorting to the pole piece of the other polarity, thereby improving the safety of the electrode assembly 10 in use. Accordingly, the thickness of the flexible barrier 14 is greater than the height of the flash to prevent the flash from piercing the flexible barrier 14 and then piercing the septum 13.

In the above embodiments, one of the end region 15 and the membrane segment may be bonded to the flexible barrier 14, and the other of the end region 15 and the membrane segment may be in slidable contact with the flexible barrier 14. For example, the end region 15 is bonded to the flexible barrier 14 and the membrane segment is in slidable contact with the flexible barrier 14. For example, the membrane section is bonded to the flexible barrier layer 14, and the end region 15 is in slidable contact with the flexible barrier layer 14.

The relative fixing of one of the end regions 15 and the membrane sections to the flexible barrier 14 is achieved by gluing, so that the flexible barrier 14 can remain in the region of the step, thereby ensuring an effective dispersion effect on the shear stress; by bringing the other of the end region 15 and the membrane segment into slidable contact with the flexible barrier 14, wrinkling of the membrane 13 caused by the end region 15, the membrane segment and the flexible barrier 14 all adhering together is avoided.

To facilitate the provision of a flexible barrier, in some embodiments, the flexible barrier 14 may include at least one single-sided adhesive paper. The adhesive effect is achieved by the adhesive side 14A of the single-sided adhesive paper and the sliding contact with the end region 15 or the surface of the membrane segment is achieved by the non-adhesive side 14B. In other embodiments, the flexible barrier 14 may also be a film layer applied to the surface of the end region 15 or septum section.

The single-sided gummed paper can comprise a gummed paper substrate and an adhesive coating layer arranged on one side surface of the gummed paper substrate, wherein the adhesive coating layer can be used as a bonding surface 14A, and the other side surface of the gummed paper substrate can be used as a non-bonding surface 14B. The material of the gummed paper substrate may include Polypropylene (PP), polyethylene terephthalate (PET), polyimide (PI), or the like. The material of the adhesive coating may include acrylic glue (i.e., PMMA glue) and the like.

Fig. 5A-5G are schematic views of the arrangement of the flexible barrier layer of some embodiments of the electrode assemblies of the present disclosure, respectively. Referring to fig. 5A, in some embodiments, the septum section comprises: a first membrane segment 131 and a second membrane segment 132. The first membrane segment 131 is located inside said end region 15. The second membrane section 132 is located outside said end region 15. The flexible barrier 14 includes a first single-sided adhesive 141 bonded to one of the first and

second membrane sections

131, 132.

The first single-sided adhesive tape 141 bonded with the side membrane section is arranged on one side of the end area 15, so that the dispersing effect of the end area 15 of the pole piece on the shearing stress of the pole piece on the inner side or the outer side of the pole piece can be realized through the first single-sided adhesive tape 141, and burrs at the cut part of the end area 15 can be separated from the side membrane section, so that the risk of lap short circuit with the other polarity pole piece caused by the burrs piercing the membrane section is avoided.

Since the adhesive surface 14A of the first single-sided gummed paper 141 is adhered to the surface of the diaphragm segment on one side of the end region 15, the non-adhesive surface 14B thereof is not adhered to the surface of the diaphragm segment on the other side of the end region 15, thereby avoiding the undesirable conditions such as lithium deposition caused by the drawing and wrinkling of the diaphragm 13 during winding due to the adhesion of the two diaphragms 13 after the first single-sided gummed paper 141 is set. In the case that the first pole piece 11 is arranged on the inner side of the second end 12B and the first pole piece 11 is not arranged on the outer side and only the diaphragm 13 is arranged on the outer side as shown in fig. 5A, the first single-sided adhesive tape 141 can be arranged only on the inner side of the end region 15 of the pole piece layer where the second end 12B is arranged, so that the step of arranging the single-sided adhesive tape on both sides of the end region 15 can be saved.

Referring to fig. 5B and 5C, in some embodiments, the flexible barrier 14 includes a first single-sided adhesive paper 141 bonded to the first membrane section 131 and a second single-sided adhesive paper 142 bonded to the second membrane section 132. By adhering the first single-sided gummed paper 141 and the second single-sided gummed paper 142 to the first membrane section 131 and the second membrane section 132 respectively, the dispersion effect of the shearing stress on the inner side and the outer side of the end region 15 can be realized through the first single-sided gummed paper 141 and the second single-sided gummed paper 142, and burrs at the cut part of the end region 15 are effectively separated from the first membrane section 131 and the second membrane section 132, so that the risk that the burrs penetrate through the membrane sections to cause lap short circuit with the other polar pole piece is reduced.

In fig. 5B, a protruding length p1 of the first single-sided offset paper 141 in the circumferential direction of the winding structure 100 with respect to the edge of the end region 15 is the same as a protruding length p2 of the second single-sided offset paper 142 in the circumferential direction of the winding structure 100 with respect to the edge of the end region 15. The protruding length here refers to the protruding length when the first single-sided offset paper 141 and the second single-sided offset paper 142 are both flat.

By making the protruding length of the first single-sided gummed paper 141 in the circumferential direction of the winding structure 100 with respect to the edge of the end region 15 the same as the protruding length of the second single-sided gummed paper 142 in the circumferential direction of the winding structure 100 with respect to the edge of the end region 15, the dispersion action of the shear stress on the inner and outer sides of the end region 15 can be made more uniform.

In fig. 5C, the protruding length of the first single-sided offset paper 141 relative to the edge of the end region 15 in the circumferential direction of the winding structure 100 may be different from the protruding length of the second single-sided offset paper 142 relative to the edge of the end region 15 in the circumferential direction of the winding structure 100. The protruding length here refers to the protruding length when the first single-sided offset paper 141 and the second single-sided offset paper 142 are both flat.

By making the protruding length of the first single-sided gummed paper 141 relative to the edge of the end region 15 in the circumferential direction of the winding structure 100 different from the protruding length of the second single-sided gummed paper 142 relative to the edge of the end region 15 in the circumferential direction of the winding structure 100, the overhanging portion of the first single-sided gummed paper 141, the end region 15 and the overhanging portion of the second single-sided gummed paper 142 can form a step with gradually changed thickness, and such a step can effectively reduce shear stress, and in cooperation with the flexibility of the first single-sided gummed paper 141 and the second single-sided gummed paper 142, the risk of the pole piece breaking due to the shear stress can be more effectively reduced.

Referring to FIG. 5D, in some embodiments, the flexible barrier 14 includes first and second single-sided

adhesive papers

141 and 142 bonded to the inside and outside surfaces of the end region 15, respectively. The protruding length of the first single-sided offset paper 141 in the circumferential direction of the winding structure 100 relative to the edge of the end region 15 is the same as or different from the protruding length of the second single-sided offset paper 142 in the circumferential direction of the winding structure 100 relative to the edge of the end region 15. The protruding length here refers to the protruding length when the first single-sided offset paper 141 and the second single-sided offset paper 142 are flat.

The inner side surface and the outer side surface of the end region 15 are bonded by the first single-sided gummed paper 141 and the second single-sided gummed paper 142 with the bonding surfaces 14A opposite to each other, and the cut part of the end region 15 is sealed by mutually bonding the protruding sections of the first single-sided gummed paper 141 and the second single-sided gummed paper 142 with the same or different protruding lengths relative to the edge of the end region 15, so that the risk of lap short circuit caused by the fact that burrs of the cut part pierce or scratch the diaphragm 13 is avoided. Moreover, the process difficulty of the bonding manner of the first single-sided adhesive paper 141 and the second single-sided adhesive paper 142 is relatively small.

Referring to FIG. 5E, in some embodiments, the flexible barrier layer 14 includes a first single-sided adhesive paper 141, and the first single-sided adhesive paper 141 is attached to both the inside and outside surfaces of the end region 15 by folding. The folding of the first single-sided adhesive paper 141 may form two opposing adhesive sides 14A and two opposing non-adhesive sides 14B. The two bonding surfaces 14A are respectively bonded with the inner side surface and the outer side surface of the end area 15, the two non-bonding surfaces 14B are in sliding contact with the membrane sections on the inner side and the outer side of the end area 15, and the folded area seals the cut part of the end area 15, so that the risk of lap short circuit caused by the fact that burrs on the cut part pierce or scratch the membrane 13 can be effectively avoided.

Referring to fig. 3, in the above embodiment, the first pole piece 11 may be a negative pole piece, and the second pole piece 12 may be a positive pole piece. In such a winding structure 100, a pole piece layer on which a first end 11B of the first pole piece 11 in the winding direction r is located may be located outside a pole piece layer on which a second end 12B of the second pole piece 12 in the winding direction r is located, and the first end 11B protrudes relative to the second end 12B in the circumferential direction of the winding structure 100.

The pole piece layer where the first tail end 11B of the first pole piece 11 is located on the outer side of the pole piece layer where the second tail end 12B of the second pole piece 12 is located, and the first tail end 11B protrudes relative to the second tail end 12B along the circumferential direction, so that the outermost negative pole piece can wrap the outermost positive pole piece, sufficient lithium embedding space is ensured for the negative pole piece, and the possibility of lithium precipitation of the outermost negative pole piece is reduced.

A flexible interlayer 14 is arranged between the end part area 15 of the pole piece layer where the first tail end 11B is located and the diaphragm section, adjacent to the end part area 15 of the pole piece layer where the first tail end 11B is located, on the diaphragm 13. A flexible interlayer 14 is arranged between the end part region 15 of the pole piece layer where the second tail end 12B is located and the diaphragm section, adjacent to the end part region 15 of the pole piece layer where the second tail end 12B is located, on the diaphragm 13.

Under the structure, the flexible interlayer 14 is arranged at the first tail end 11B and the second tail end 12B, so that the shearing stress of the steps formed at the first tail end 11B and the second tail end 12B on the pole pieces can be dispersed in the circulation process of the electrode assembly 10, the risk of the pole pieces being broken due to the action of the shearing force is reduced, and the use reliability of the electrode assembly 10 is improved; and for the second end 12B, the flexible barrier layer 14 may separate the burrs at the cut-off portion of the end region thereof from the separator 13 to prevent the burrs from piercing the separator 13 and shorting with the negative electrode tab.

Still referring to fig. 3, in the winding structure 100 of the embodiment in which the first pole piece 11 is a negative pole piece and the second pole piece 12 is a positive pole piece, the pole piece layer where the first starting end 11A of the first pole piece 11 in the winding direction r is located inside the pole piece layer where the second starting end 12A of the second pole piece 12 in the winding direction r is located, and the first starting end 11A protrudes relative to the second starting end 12A in the circumferential direction of the winding structure 100. The pole piece layer where the first starting end 11A of the first pole piece 11 is located on the inner side of the pole piece layer where the second starting end 12A of the second pole piece 12 is located, and the first starting end 11A protrudes relative to the second starting end 12A along the circumferential direction, so that the negative pole piece can be ensured to have a sufficient lithium embedding space, and the possibility of lithium precipitation of the negative pole piece at the innermost layer is reduced.

A flexible interlayer 14 is arranged between the end region 15 of the pole piece layer where the second starting end 12A is located and the diaphragm section, adjacent to the end region 15 of the pole piece layer where the second starting end 12A is located, on the diaphragm 13. In such a structure, by disposing the flexible interlayer 14 at the second starting end 12A, the shear stress of the step formed at the second starting end 12A on the pole piece can be dispersed in the cycle process of the electrode assembly 10, so as to reduce the risk of the pole piece being broken by the shear force, thereby improving the reliability of the electrode assembly 10. Since the center winding of the electrode assembly 10 is loose, the negative electrode tab can be wound several times without any extra space, so that the first starting end 11A does not need to be provided with the flexible barrier layer 14, and there is no fear that burrs at the cut part of the end region 11A of the first starting end 11A will pierce the separator 13 and overlap and short-circuit the positive electrode tab.

Referring to fig. 5F and 5G, in some embodiments, at least one of the first and

second pole pieces

11 and 12 includes: a current collector substrate 10A and an active material layer 10B. The active material layer 10B is provided at least on the surface of the current collector substrate 10A on the side adjacent to the separator 13. The current collector substrate 10A and the active material layer 10B in the positive electrode sheet are a positive electrode current collector substrate and a positive electrode active material layer, respectively. The current collector substrate 10A and the active material layer 10B in the negative electrode plate are a negative electrode current collector substrate and a negative electrode active material layer, respectively.

In the winding direction r, at least one end of the current collector substrate 10A is not covered with the active material layer 10B at a surface portion corresponding to the end region 15. In fig. 5F, the flexible separator layer 14 may be disposed on the surface portion of the end region 15 corresponding to the current collector substrate 10A not covered with the active material layer 10B, with the step height formed at the end region 15 being reduced compared to when the flexible separator layer 14 is disposed on the active material layer 10B. Further, the structure shown in fig. 5F also forms a multi-step structure in which the active material layer 10B, the current collector substrate 10A, and the flexible separator layer 14 are sequentially changed.

By leaving the portion of the current collector substrate 10A of the electrode sheet corresponding to the end region 15 uncovered with the active material layer 10B, the step height of the end region 15 can be reduced regardless of whether the flexible separator layer 14 is provided in the end region 15, so that the shear stress caused by the step when the electrode assembly 10 is cyclically expanded is reduced, the risk of the electrode sheet being broken due to the shear stress is reduced, and the reliability of the electrode assembly 10 in use is improved.

The flexible barrier layer 14 may be provided at both the beginning and the end of each of the first pole piece 11 and the second pole piece 12, or the flexible barrier layer 14 may be provided only in the portion of the beginning and the end of each of the first pole piece 11 and the second pole piece 12. For the first end 11B in fig. 3, the adjacent pole piece layer inside itself may not be provided with the flexible interlayer 14, but a lower step height may be formed by not covering the active material layer 10B with the portion of the current collector substrate 10A corresponding to the end region 15 as shown in fig. 5G, so as to reduce the shear stress caused by the step at this position when the electrode assembly 10 is cyclically expanded, thereby reducing the risk of the pole piece breaking due to the shear stress, and further improving the reliability of the electrode assembly 10.

Fig. 6A is a schematic view of a portion of an electrode assembly of the present disclosure in an expanded state at an end region in some embodiments. Fig. 6B is a schematic size diagram of fig. 6A. FIG. 6C is a schematic view of the AA cross-section of FIG. 6A. Referring to fig. 2B, 6A, and 6B, in some embodiments, the rolled structure 100 is a cylindrical rolled structure, and the length L of the flexible barrier layer 14 in the rolling direction r satisfies: l is not less than 0.03 pi X D and not more than 0.25 pi X D. D is the diameter of the cylindrical winding structure.

The flexible barrier layer 14 disposed between the pole piece and the separator 13 may block a portion of the area of the lithium ion diffusion channel, and if the length L of the flexible barrier layer 14 in the winding direction r is too large compared to the cross section Zhou Chang × D of the cylindrical wound structure, the effect on lithium ion diffusion is large, thereby affecting the performance of the electrode assembly 10.

If this length L is too small compared to the cross-section Zhou Chang x D of the cylindrical wound structure, the adhesive fixing effect between the flexible barrier layer 14 and the pole piece or membrane 13 is weakened, resulting in the flexible barrier layer 14 easily coming out of position. Also, it is difficult to provide an excessively small length L when manufacturing the electrode assembly 10, resulting in an increase in difficulty in manufacturing the electrode assembly 10.

Therefore, the length L is more than or equal to 0.03 pi times of the diameter D and less than or equal to 0.25 pi times of the diameter D, so that the flexible interlayer 14 and the pole piece or the diaphragm 13 can be reliably bonded and fixed, the arrangement difficulty of the flexible interlayer 14 is reduced, the blocking of the flexible interlayer 14 to a lithium ion diffusion channel can be reduced, and the influence on the performance of the electrode assembly 10 is reduced.

In some embodiments, the length L satisfies: 0.07 π D ≦ L ≦ 0.13 π D, e.g., L equal to 0.09 π D, 0.1 π D, 0.12 π D, etc. By making the length L greater than or equal to 0.07 pi times the diameter D and less than or equal to 0.13 pi times the diameter D, the flexible interlayer 14 and the pole piece or diaphragm 13 can be more reliably bonded and fixed, the difficulty in arranging the flexible interlayer 14 is further reduced, and the blocking of the flexible interlayer 14 to a lithium ion diffusion channel can be effectively reduced, thereby reducing the influence of the flexible interlayer 14 on the performance of the electrode assembly 10.

The technical effect of taking different lengths L and thicknesses D is illustrated by several experimental and comparative examples shown in the following table.

Diameter D (mm)	Length L (mm)	L/(π*D)	Effect
				90	10	0.0354	The flexible interlayer is not loosened
90	35	0.1238	The flexible interlayer is not loosened
				120	10	0.0265	Flexible interlayer release
120	35	0.0928	The flexible interlayer is not loosened

Referring to fig. 6B, in some embodiments, the coiled structure 100 is a cylindrical coiled structure, and the width W of the flexible barrier 14 in the direction of extension of the axis ax of the cylindrical coiled structure satisfies: w is more than or equal to W1 and less than or equal to H. W1 is the width of the end zone 15 in the direction of extension of the axis ax of the cylindrical winding and H is the height of the cylindrical winding in the direction of extension of the axis ax of the cylindrical winding. The height H of the cylindrical winding structure may be the maximum distance from the tab surface at one end of the cylindrical winding structure (i.e. the flattened end surface of the side tab) to the tab surface at the other end (i.e. the flattened end surface of the side tab) in the extending direction of the axis of the cylindrical winding structure.

If the width W of the flexible barrier layer 14 is less than the width W1 of the end region 15, this means that there are parts of the pole piece between the end region 15 and the membrane 13 which are not covered by the flexible barrier layer 14, and these parts risk breaking the pole piece due to excessive shear stress, since the shear stress is not distributed by the flexible barrier layer 14.

If the width W of the flexible interlayer 14 is greater than the height H of the cylindrical winding structure 100, the tab at the end of the cylindrical winding structure 100 is exceeded due to the overlong flexible interlayer 14, which affects the subsequent processes of tab smoothing welding, and in order not to affect the subsequent processes, the overlong flexible interlayer 14 needs to be cut off, so that the manufacturing links are increased, and the manufacturing cost is increased.

Therefore, by making the width W of the flexible interlayer 14 satisfy W1 ≦ W ≦ H, the risk of pole piece breakage due to shear stress when the electrode assembly 10 is cyclically expanded can be reduced, and adverse effects on subsequent processes are reduced.

Still referring to fig. 6B, in some embodiments, the protruding length L1 of the flexible barrier layer 14 relative to the edge of the end region 15 in the circumferential direction of the rolled structure 100 satisfies: l is more than or equal to (1/4) and less than or equal to L1 and less than or equal to (3/4) L. L is the length of the flexible barrier 14 in the winding direction r.

The relationship of the bulge length L1 of the flexible barrier layer 14 to the length L of the flexible barrier layer 14 represents the position of the flexible barrier layer 14 relative to the edge of the end region 15, and if the bulge length L1 is too small or too large compared to the length L, the flexible barrier layer 14 is prone to being incorrectly positioned between the end region 15 of the pole piece and the diaphragm 13 due to fluctuations in the actual bonding position of the flexible barrier layer 14.

When the flexible barrier layer 14 is not or only very slightly located between the end regions 15 of the pole pieces and the separator 13, or the flexible barrier layer 14 does not overhang the edges of the electrode assembly 10 in the circumferential direction with respect to the end regions 15, it results in the flexible barrier layer 14 being difficult to effectively distribute shear stresses.

Therefore, by setting the protrusion length L1 to be equal to or greater than 1/4 times L and equal to or less than 3/4 times L, the flexible interlayer 14 can effectively overcome the influence of fluctuation of the actual bonding position of the flexible interlayer 14, and ensure the dispersing action of the flexible interlayer 14 on the shear stress.

In some embodiments, the protrusion length L1 satisfies: (1/3) ≦ L1 ≦ 2/3) × L, e.g., L1 equals (3/8) × L, (1/2) × L, and the like. By making the protrusion length L1 greater than or equal to 1/3 times L and less than or equal to 2/3 times L, the flexible interlayer 14 can more effectively overcome the influence of fluctuation of the actual bonding position of the flexible interlayer 14, and further ensure the dispersion effect of the flexible interlayer 14 on the shear stress.

Referring to FIG. 6C, in some embodiments, the thickness T of the flexible barrier 14 satisfies: t is more than or equal to 0.07 and less than or equal to 0.8. t is the thickness of the pole piece adjacent to the flexible interlayer 14 in the first pole piece 11 and the second pole piece 12 after the electrode assembly 10 is charged and discharged for the first time.

When the electrode assembly 10 is cyclically expanded, the flexible interlayer 14 can disperse the shearing stress of the steps formed at the ends of the pole pieces to the adjacent pole piece layers, so that the fracture risk is reduced, but the height of the steps of the end area 15 relative to the adjacent pole piece layers is increased after the flexible interlayer 14 is arranged.

If the thickness T of the flexible barrier layer 14 is too small compared to the thickness T of the pole piece, the too thin flexible barrier layer 14 is difficult to effectively disperse the shear stress at the step, increasing the risk of breaking the pole piece. If the thickness T of the flexible barrier layer 14 is too great compared to the thickness T of the pole pieces, the end regions 15 form a higher step after the provision of the too thick flexible barrier layer 14, which in turn leads to an increase in the shear stress at the step.

Therefore, by making the thickness T of the flexible barrier layer 14 greater than or equal to 0.07 times the thickness T of the pole piece and less than or equal to 0.8 times the thickness T of the pole piece, the shear stress at the step can be effectively dispersed when the electrode assembly 10 is cyclically expanded, reducing the risk of breaking the pole piece due to excessive shear stress.

In some embodiments, the thickness T satisfies: 0.2 × T ≦ 0.5 × T, e.g., T equal to 0.3 × T, 0.36 × T, 0.42 × T, etc. By making the thickness T of the flexible barrier layer 14 greater than or equal to 0.2 times the thickness T of the pole piece and less than or equal to 0.5 times the thickness T of the pole piece, the shear stress at the step can be more effectively dispersed when the electrode assembly 10 is cyclically expanded, further reducing the risk of breaking the pole piece due to excessive shear stress.

To illustrate the effect of the flexible barrier, a number of experimental examples are provided below for verification. In the experimental examples, the first pole piece as the negative pole piece and the second pole piece as the positive pole piece are both provided with a flexible interlayer between the end area and the inner side membrane section at the end area of the tail end, and the flexible interlayer is single-sided adhesive paper with an adhesive surface adhered with the membrane section. The length L of the single-sided gummed paper is 10mm, the width W is 87mm, and the protruding length L1 is 5mm. The electrode structure glued by single-sided adhesive paper with different thicknesses is packaged in a shell to obtain a cylindrical battery monomer, and a cycle test is carried out, wherein the test condition is 45 ℃, charging and discharging are carried out at the rate of 0.5C (namely 1/2 time of the capacity C of the battery monomer), the cycle depth is 10% of the battery state of charge (SOC) to 100% of SOC, and the test is stopped when the capacity of the battery monomer is attenuated to 80%. And disassembling the tested electrode assembly, and observing the fracture condition of the pole piece.

Referring to the above examples, in many experimental examples, the thickness T of the pole piece is 160 μm,0.07 times T is 11.2 μm,0.8 times T is 128 μm, and the thickness T of the flexible barrier layer 14 is 0 μm, 5 μm, and 150 μm, respectively, which are outside the value range of 11.2 μm to 128 μm, and it can be observed that the corresponding inner ring negative pole piece at the step of the end region has been broken. In the other two groups of experimental examples, the thickness T of the pole piece is 160 μm, the thickness T of the flexible interlayer 14 is 30 μm and 60 μm, and the values are all in the numerical range from 11.2 μm to 128 μm, and it can be observed that the inner ring negative pole piece corresponding to the step of the end region is not broken.

Fig. 7A is a schematic structural view of some embodiments of an electrode assembly of the present disclosure. Fig. 7B is a schematic size diagram of fig. 7A. Fig. 7C is a schematic cross-sectional view of the third single-sided adhesive paper of fig. 7A adhered to the third end of the membrane. Referring to fig. 3 and 7A, in some embodiments, the pole piece layer where the first end 11B of the first pole piece 11 in the winding direction r is located and the pole piece layer where the second end 12B of the second pole piece 12 in the winding direction r is located are both located on the inner side of the separator layer where the third end 133 of the separator 13 in the winding direction r is located, and the third end 133 protrudes in the circumferential direction of the winding structure 100 relative to the first end 11B and the second end 12B, and the third end 133 is adhesively fixed on the electrode assembly 10 by a third single-sided adhesive tape 16.

In fig. 7A, the edge 133a of the third end 133 is adhesively secured by the third single-sided adhesive paper 16, and since a portion of the third single-sided adhesive paper 16 is adhered to the third end 133 and another portion is adhered to the membrane layer inside the third end 133, the third single-sided adhesive paper 16 straddles the edge 133a. The structure of the third single-sided adhesive paper 16 can refer to the aforementioned first single-sided adhesive paper, and is not described herein again.

The pole piece layer where the first end 11B is located and the pole piece layer where the second end 12B is located are both arranged on the inner side of the diaphragm layer where the third end 133 is located, and the third end 133 protrudes relative to the first end 11B and the second end 12B in the circumferential direction of the winding structure 100, so that the wrapping effect of the diaphragm 13 layer on the first pole piece 11 and the second pole piece 12 can be ensured, and the exposure of the pole piece ends is avoided. The adhesive fixation is achieved by providing the third single-sided adhesive paper 16 at the third end 133 of the separator 13, and the end fixing effect of the separator 13 can be achieved, ensuring that the wound electrode assembly 10 is not loosened.

Referring to fig. 7B, in some embodiments, the winding structure 100 is a cylindrical winding structure, and the length L2 of the third single-sided offset paper 16 in the winding direction r satisfies: l2 is more than or equal to 0.07 pi x D and less than or equal to 1.5 pi x D. D is the diameter of the cylindrical winding structure.

The relationship between the length L2 of the third single-sided gummed paper 16 in the winding direction r and the cross section Zhou Chang × D of the cylindrical winding structure represents the wrapping degree of the third single-sided gummed paper 16 on the periphery of the cylindrical winding structure. If the length L2 of the third single-sided adhesive tape 16 is too small compared with the cross section Zhou Chang × D of the cylindrical winding structure, the effect of fixing the end of the separator 13 by the third single-sided adhesive tape 16 is affected, and there is a risk that the electrode assembly 10 is loosened due to poor adhesion and fixation.

If the length L2 of the third single-sided adhesive paper 16 is excessively large compared to the cross section Zhou Chang × D of the cylindrical winding structure, the thickness may be increased due to excessive overlapping of the third single-sided adhesive paper 16, thereby increasing the cross-sectional size of the electrode assembly 10, resulting in an increase in difficulty in the entry of the electrode assembly 10 into the case 21 of the battery cell.

Therefore, by setting the length L2 to 0.07 pi times or more and 1.5 pi times or less the diameter D, the electrode assembly 10 can be firmly bonded without loosening, and the battery cell can be easily inserted into the case 21.

In some embodiments, length L2 satisfies: 0.25 π D ≦ L2 ≦ 1.05 π D, e.g., L2 equal to 0.4 π D, 0.75 π D, etc. By making the length L2 greater than or equal to 0.25 pi times the diameter D and less than or equal to 1.05 pi times the diameter D, the electrode assembly 10 can be bonded more securely without loosening, and the entry of the electrode assembly 10 into the case 21 of the battery cell is further facilitated.

Further, the length L2 may satisfy: pi x D < L2 ≦ 1.05 pi x D, e.g., L2 equals 1.02 pi x D, 1.03 pi x D, etc. By making the length L2 larger than the diameter D of pi times and smaller than or equal to 1.05 pi times the diameter D, the third single-sided gummed paper 16 can be overlapped a small amount while adhesively fixing the end of the separator 13, so that the number of steps formed on the separator 13 by the end of the third single-sided gummed paper 16 is reduced, the effect of the steps formed by the third single-sided gummed paper 16 on the shear stress of the pole piece when the electrode assembly 10 is cyclically expanded is reduced, and the risk of the pole piece breaking under the effect of the shear stress is reduced.

Referring to fig. 7A, in some embodiments, the winding structure 100 is a cylindrical winding structure, the number of the third single-sided gummed papers 16 is two, and two third single-sided gummed papers 16 are arranged at intervals along an extending direction of an axis ax of the cylindrical winding structure. By arranging the two third single-sided adhesive tapes 16 which are arranged at intervals along the extending direction of the axis ax, the requirement of bonding and fixing can be met, and meanwhile, the third single-sided adhesive tapes 16 are prevented from forming excessive binding force on the electrode assembly 10, so that the extending rate of the current collector base material of the electrode assembly 10 is reduced, and the adhesive tape consumption of the third single-sided adhesive tapes 16 is reduced.

Referring to fig. 7A and 7B, in some embodiments, in the extending direction of the axis ax of the cylindrical winding structure, the minimum distance from the third one-sided gummed paper 16 adjacent to the first end 100A of the cylindrical winding structure to the first end 100A of the two third one-sided gummed papers 16 is h1, the width from the third one-sided gummed paper 16 adjacent to the first end 100A of the cylindrical winding structure is W2, and the minimum distance from the third one-sided gummed paper 16 adjacent to the second end 100B of the cylindrical winding structure to the second end 100B of the two third one-sided gummed papers 16 is h2.

The width of the third single-sided gummed paper 16 adjacent to the second end 100B of the cylindrical winding structure in the two third single-sided gummed papers 16 is W3, and h1, W2, h2 and W3 satisfy: h1 is more than or equal to 0 and less than or equal to 0.07 x H, h2 is more than or equal to 0 and less than or equal to 0.07 x H, W2 is more than or equal to 0.05 x H and less than or equal to 0.12 x H, and W3 is more than or equal to 0.05 x H and less than or equal to 0.12 x H. For example h1 equals 0.02, 0.04, 0.055, etc., h2 equals 0.015, 0.035, 0.56, etc., W2 equals 0.07, 0.09, 0.11, W3 equals 0.06, 0.08, 0.1. H is the height of the cylindrical winding in the direction of extension of the axis ax of the cylindrical winding.

The minimum distances h1 and h2 from the two third single-sided gummed papers 16 to the two ends of the cylindrical winding structure respectively represent the degree of the third single-sided gummed paper 16 approaching the end of the winding structure 100, and the widths W2 and W3 represent the range covered by the third single-sided gummed paper 16.

By making h1 and h2 satisfy 0 ≦ h1 ≦ 0.07 × h,0 ≦ h2 ≦ 0.07 × h, and making W2 and W3 satisfy 0.05 × h ≦ W2 ≦ 0.12 × h, and 0.05 × h ≦ W3 ≦ 0.12 × h, the third single-sided adhesive sheet 16 can be made to mainly adhere to the active material coating thinning region on both sides of the pole piece, which makes it possible to apply the third single-sided adhesive sheet 16 in a wider thickness range, and even if a relatively thick third single-sided adhesive sheet 16 is used, the entry of the electrode assembly 10 into the case 21 of the battery cell is not easily affected.

Referring to fig. 7C, in some embodiments, the thickness T1 of the third single-sided offset paper 16 satisfies: t1 is more than or equal to 5 mu m and less than or equal to 120 mu m. For example T1 equals 10 μm, 40 μm, 85 μm, 115 μm, etc. The excessively thin third single-sided adhesive sheet 16 has a low tensile strength, and there is a risk that the third single-sided adhesive sheet 16 is broken by a tensile force when the electrode assembly 10 is cyclically expanded, resulting in loosening of the electrode assembly 10. The excessively thick third single-sided adhesive sheet 16 increases the outer size of the electrode assembly 10, resulting in an increased difficulty in the entry of the electrode assembly 10 into the case 21.

Therefore, when the minimum distances h1 and h2 and the widths W2 and W3 satisfy the proper value ranges, the thickness T1 of the third single-sided adhesive paper 16 satisfies that T1 is not less than 5 μm and not more than 120 μm, so that the third single-sided adhesive paper 16 has proper tensile strength, the risk of the third single-sided adhesive paper 16 breaking under the action of tensile force when the electrode assembly 10 is circularly expanded is reduced, the overall outer contour size of the electrode assembly 10 bonded with the third single-sided adhesive paper 16 is more proper, and the electrode assembly 10 is prevented from interfering with the casing 21 when entering the casing 21.

Referring to fig. 7A and 7B, in some embodiments, in the extending direction of the axis ax of the cylindrical winding structure, the minimum distance from the third one-sided gummed paper 16 adjacent to the first end 100A of the cylindrical winding structure to the first end of the two third one-sided gummed papers 16 is h1, the width of the third one-sided gummed paper 16 adjacent to the first end 100A of the cylindrical winding structure of the two third one-sided gummed papers 16 is W2, and the minimum distance from the third one-sided gummed paper 16 adjacent to the second end 100B of the cylindrical winding structure of the two third one-sided gummed papers 16 to the second end is h2. The width of the third single-sided gummed paper 16 adjacent to the second end 100B of the cylindrical winding structure in the two third single-sided gummed papers 16 is W3, and h1, W1, h2 and W2 satisfy: 0.07 × H is not less than h1 and not more than 0.25 × H,0.07 × H is not less than h2 and not more than 0.25 × H,0.05 × H is not less than W2 and not more than 0.23 × H, and 0.05 × H is not less than W3 and not more than 0.23 × H. For example h1 equals 0.09 × h, 0.15 × h, 0.22 × h, etc., h2 equals 0.1 × h, 0.18 × h, 0.24 × h, etc., W2 equals 0.12 × h, 0.18 × h, 0.22 × h, W3 equals 0.1 × h, 0.16 × h, 0.2 × h. H is the height of the cylindrical winding in the direction of extension of the axis ax of the cylindrical winding.

By making h1 and h2 satisfy 0.07 x h1 h 0.25 x h 0.07 x h2 h 0.25 x h and W2 and W3 satisfy 0.05 x h W2W 0.23 x h and 0.05 x h W3W 0.23 x h, the third single-sided adhesive sheet 16 can be adhered to an area of normal thickness of the active material coating in addition to the reduced area of active material coating on both sides of the electrode sheet, and therefore, a relatively small thickness range of the third single-sided adhesive sheet 16 is applicable, and the adhesion firmness is improved by increasing the width of the third single-sided adhesive sheet 16, so that the electrode assembly 10 is not easily loosened.

Referring to fig. 7C, in some embodiments, the thickness T1 of the third single-sided offset paper 16 satisfies: t1 is more than or equal to 5 mu m and less than or equal to 60 mu m. For example T1 equals 12 μm, 24 μm, 32 μm, 46 μm, 52 μm, etc. The third single-sided adhesive sheet 16, which is too thin, has a low tensile strength, and there is a risk that the third single-sided adhesive sheet 16 is broken by a tensile force when the electrode assembly 10 is cyclically expanded, resulting in loosening of the electrode assembly 10. An excessively thick third single-sided adhesive sheet 16 increases the outer dimensions of the electrode assembly 10, resulting in an increased difficulty in the electrode assembly 10 entering the case 21.

Therefore, when the minimum distances h1 and h2 and the widths W2 and W3 satisfy the proper value ranges, the thickness T1 of the third single-sided adhesive paper 16 satisfies 5 μm or more and T1 or more and 60 μm or less, so that the third single-sided adhesive paper 16 has proper tensile strength, the risk of the third single-sided adhesive paper 16 breaking under the action of tensile force when the electrode assembly 10 circularly expands is reduced, the overall outer contour size of the electrode assembly 10 bonded with the third single-sided adhesive paper 16 is more proper, and the electrode assembly 10 is prevented from interfering with the case 21 when entering the case 21.

Based on various embodiments of the electrode assembly disclosed above, embodiments of the present disclosure also provide a battery cell including the electrode assembly described above. The battery cell using the foregoing embodiment of the electrode assembly can achieve superior reliability in use.

In one aspect of the present disclosure, a battery is provided, which includes the aforementioned battery cell. The battery adopting the battery cell can obtain better use reliability.

In one aspect of the present disclosure, an electric device is provided, which includes the aforementioned battery. The electric equipment adopting the battery can obtain better use reliability.

Based on various embodiments of the foregoing battery cell of the present disclosure, the present disclosure also provides embodiments of a battery employing the foregoing battery cell embodiments. The battery comprises the battery cell of any one of the embodiments. The battery adopting the battery single-cell embodiment can obtain better use reliability.

While the disclosure has been described with reference to a preferred embodiment, various modifications may be made and equivalents may be substituted for elements thereof without departing from the scope of the disclosure. In particular, the technical features mentioned in the embodiments can be combined in any way as long as there is no structural conflict. The present disclosure is not intended to be limited to the particular embodiments disclosed herein, but includes all embodiments falling within the scope of the appended claims.

Claims

1. An electrode assembly, comprising: the winding structure comprises a first pole piece (11), a second pole piece (12) and a diaphragm (13) arranged between the first pole piece (11) and the second pole piece (12), wherein the first pole piece (11), the second pole piece (12) and the diaphragm (13) are wound along a winding direction (r) to form a winding structure (100);

wherein a flexible spacer layer (14) is arranged between an end region (15) of at least one end of the first pole piece (11) and the second pole piece (12) in the winding direction (r) and a membrane section of the membrane (13) adjacent to the end region (15), the flexible spacer layer (14) protruding beyond the edge of the end region (15) in the circumferential direction of the wound structure (100).

2. The electrode assembly of claim 1, wherein one of the end region (15) and the membrane section is bonded to the flexible barrier layer (14) and the other of the end region (15) and the membrane section is in slidable contact with the flexible barrier layer (14).

3. The electrode assembly of claim 2, wherein the flexible barrier layer (14) comprises at least one single-sided adhesive paper.

4. The electrode assembly of any one of claims 1 to 3, wherein the separator segment comprises:

a first membrane segment (131) located inside the end region (15);

a second membrane section (132) located outside the end region (15);

wherein the flexible barrier (14) comprises a first single-sided adhesive paper (141) bonded to one of the first membrane section (131) and the second membrane section (132).

5. The electrode assembly of any one of claims 1 to 3, wherein the separator segment comprises:

a first membrane segment (131) located inside the end region (15);

a second membrane section (132) located outside the end region (15);

wherein the flexible interlayer (14) comprises a first single-sided gummed paper (141) and a second single-sided gummed paper (142) which are respectively bonded with the first membrane section (131) and the second membrane section (132), and the protruding length of the first single-sided gummed paper (141) relative to the edge of the end area (15) in the circumferential direction of the winding structure (100) is the same as or different from the protruding length of the second single-sided gummed paper (142) relative to the edge of the end area (15) in the circumferential direction of the winding structure (100).

6. An electrode assembly according to any one of claims 1 to 3, wherein the flexible separator layer (14) comprises a first single-sided adhesive paper (141), the first single-sided adhesive paper (141) being bonded to both the inside and outside surfaces of the end region (15) by folding.

7. The electrode assembly according to any one of claims 1 to 3, wherein the flexible separator layer (14) comprises a first single-sided adhesive paper (141) and a second single-sided adhesive paper (142) bonded to the inner side surface and the outer side surface of the end region (15), respectively, and a protruding length of the first single-sided adhesive paper (141) with respect to the edge of the end region (15) in the circumferential direction of the rolled structure (100) is the same as or different from a protruding length of the second single-sided adhesive paper (142) with respect to the edge of the end region (15) in the circumferential direction of the rolled structure (100).

8. The electrode assembly according to claim 1, wherein the first pole piece (11) is a negative pole piece and the second pole piece (12) is a positive pole piece.

9. The electrode assembly according to claim 8, characterized in that in the wound structure (100) the pole piece layer of the first pole piece (11) in the winding direction (r) is located at a first end (11B) thereof located outside the pole piece layer of the second pole piece (12) at a second end (12B) thereof located in the winding direction (r), and the first end (11B) is projected in the circumferential direction of the wound structure (100) with respect to the second end (12B), a flexible barrier layer (14) is provided between an end region (15) of the pole piece layer where the first end (11B) is located and a diaphragm segment of the diaphragm (13) adjacent to the end region (15) of the pole piece layer where the first end (11B) is located, and a flexible barrier layer (14) is provided between the end region (15) of the pole piece layer where the second end (12B) is located and the diaphragm segment of the diaphragm (13) adjacent to the end region (15) of the pole piece layer where the second end (12B) is located.

10. Electrode assembly according to claim 8 or 9, characterized in that in the wound structure (100) a pole piece layer at which a first start (11A) of the first pole piece (11) in the winding direction (r) is located inside a pole piece layer at which a second start (12A) of the second pole piece (12) in the winding direction (r) is located, and the first start (11A) is convex with respect to the second start (12A) in the circumferential direction of the wound structure (100), a flexible barrier layer (14) being provided between an end region (15) of the pole piece layer at which the second start (12A) is located and a membrane segment of the membrane (13) adjacent to the end region (15) of the pole piece layer at which the second start (12A) is located.

11. The electrode assembly according to claim 1, characterized in that at least one of the first pole piece (11) and the second pole piece (12) comprises:

a current collector substrate (10A);

an active material layer (10B) provided at least on a surface of the current collector substrate (10A) on a side adjacent to the separator (13);

wherein, in the winding direction (r), a surface portion of at least one end of the current collector substrate (10A) corresponding to the end region (15) is not covered with the active material layer (10B).

12. The electrode assembly of claim 1, wherein the coiled structure (100) is a cylindrical coiled structure, and the length L of the flexible barrier layer (14) in the coiling direction (r) satisfies:

0.03π*D≤L≤0.25π*D；

wherein D is the diameter of the cylindrical winding structure.

13. The electrode assembly of claim 12, wherein the length L satisfies: l is more than or equal to 0.07 pi and less than or equal to 0.13 pi and D.

14. The electrode assembly of claim 1, wherein the coiled structure (100) is a cylindrical coiled structure, and the width W of the flexible barrier layer (14) in the axial direction of the cylindrical coiled structure satisfies:

W1≤W≤H；

wherein W1 is the width of the end region (15) in the axial direction of the cylindrical winding and H is the height of the cylindrical winding in the axial direction of the cylindrical winding.

15. The electrode assembly according to claim 1, characterized in that the protruding length L1 of the flexible barrier layer (14) in the circumferential direction of the rolled structure (100) relative to the edge of the end region (15) satisfies:

(1/4)*L≤L1≤(3/4)*L；

wherein L is the length of the flexible barrier layer (14) in the winding direction (r).

16. The electrode assembly of claim 15, wherein the projection length L1 satisfies: l is more than or equal to (1/3) and less than or equal to L1 and less than or equal to (2/3) L.

17. The electrode assembly of claim 1, wherein the thickness T of the flexible barrier layer (14) is such that:

0.07*t≤T≤0.8*t；

and t is the thickness of the pole piece which is arranged in the first pole piece (11) and the second pole piece (12) and is adjacent to the flexible interlayer (14) after the electrode assembly (10) is charged and discharged for the first time.

18. The electrode assembly of claim 17, wherein the thickness T satisfies: t is more than or equal to 0.2 and less than or equal to 0.5.

19. The electrode assembly according to claim 1, wherein a pole piece layer where a first end (11B) of the first pole piece (11) in the winding direction (r) is located and a pole piece layer where a second end (12B) of the second pole piece (12) in the winding direction (r) is located are both located inside a separator layer where a third end (133) of the separator (13) in the winding direction (r) is located, and the third end (133) protrudes in a circumferential direction of the wound structure (100) with respect to both the first end (11B) and the second end (12B), and the third end (133) is adhesively fixed on the electrode assembly (10) by a third single-sided adhesive paper (16).

20. The electrode assembly according to claim 19, wherein the winding structure (100) is a cylindrical winding structure, and a length L2 of the third single-sided adhesive paper (16) in the winding direction (r) satisfies:

0.07π*D≤L2≤1.5π*D；

wherein D is the diameter of the cylindrical winding structure.

21. The electrode assembly of claim 20, wherein the length L2 satisfies: l2 is not less than 0.25 pi x D and not more than 1.05 pi x D.

22. The electrode assembly of claim 21, wherein the length L2 satisfies: pi x D < L2 is less than or equal to 1.05 pi x D.

23. The electrode assembly according to any one of claims 19 to 22, wherein the winding structure (100) is a cylindrical winding structure, the third single-sided adhesive tape (16) is provided in two, and the two third single-sided adhesive tapes (16) are arranged at intervals along an extending direction of an axis (ax) of the cylindrical winding structure.

24. The electrode assembly according to claim 23, wherein in the extending direction of the axis (ax) of the cylindrical winding structure, the minimum distance from the third one-sided adhesive paper (16) adjacent to the first end (100A) of the cylindrical winding structure to the first end (100A) of the two third one-sided adhesive papers (16) is h1, the minimum distance from the third one-sided adhesive paper (16) adjacent to the first end (100A) of the cylindrical winding structure of the two third one-sided adhesive papers (16) adjacent to the first end (100A) of the cylindrical winding structure is W2, the minimum distance from the third one-sided adhesive paper (16) adjacent to the second end (100B) of the cylindrical winding structure of the two third one-sided adhesive papers (16) to the second end (100B) of the cylindrical winding structure is h2, the widths of the third one-sided adhesive papers (16) adjacent to the second end (100B) of the cylindrical winding structure of the two third one-sided adhesive papers (16) are W3, h1, W2, h2, and W3 satisfy:

wherein H is the height of the cylindrical winding in the direction of extension of the axis (ax) of the cylindrical winding.

25. The electrode assembly of claim 24, wherein the thickness T1 of the third single-sided adhesive paper (16) satisfies: t1 is more than or equal to 5 mu m and less than or equal to 120 mu m.

26. The electrode assembly according to claim 23, wherein in the extending direction of the axis (ax) of the cylindrical winding structure, the minimum distance from the third one-sided adhesive paper (16) adjacent to the first end (100A) of the cylindrical winding structure of the two third one-sided adhesive papers (16) to the first end is h1, the minimum distance from the third one-sided adhesive paper (16) adjacent to the first end (100A) of the cylindrical winding structure of the two third one-sided adhesive papers (16) to the second end is h2, the minimum distance from the third one-sided adhesive paper (16) adjacent to the second end (100B) of the cylindrical winding structure of the two third one-sided adhesive papers (16) is W3, and the widths of the third one-sided adhesive papers (16) adjacent to the second end (100B) of the cylindrical winding structure of the two third one-sided adhesive papers (16) are W3, h1, W1, h2 and W2 satisfy:

27. The electrode assembly of claim 26, wherein the thickness T1 of the third single-sided adhesive paper (16) satisfies: t1 is more than or equal to 5 mu m and less than or equal to 60 mu m.

28. A battery cell, comprising: the electrode assembly (10) of any of claims 1-27.

29. A battery comprising the battery cell (20) of claim 28.

30. An electric consumer, characterized in that it comprises a battery (30) according to claim 29.