CN218769985U

CN218769985U - Electrode assembly, battery cell, battery, power utilization device and tab shaping device

Info

Publication number: CN218769985U
Application number: CN202222396362.XU
Authority: CN
Inventors: 赵丰刚; 金海族; 柴志生; 谷慧
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2022-09-06
Filing date: 2022-09-06
Publication date: 2023-03-28
Anticipated expiration: 2032-09-06

Abstract

The application provides an electrode subassembly, battery monomer, battery, power consumption device and utmost point ear shaping device. The electrode assembly includes: the winding structure comprises a first pole piece, a second pole piece and a diaphragm, wherein the polarity of the first pole piece is opposite to that of the second pole piece, and the diaphragm is arranged between the first pole piece and the second pole piece; wherein, at least one in first pole piece and the second pole piece includes: a current collector; an active material layer provided at least on a surface of the current collector on a side adjacent to the separator; and the lug part is connected to one side of the current collector extending along the winding direction, the lug part comprises a continuous area close to the active material layer and an interval area far away from the active material layer, and the interval area comprises a plurality of lugs arranged at intervals along the winding direction.

Description

Electrode assembly, battery cell, battery, power utilization device and tab shaping device

Technical Field

The application relates to the technical field of batteries, in particular to an electrode assembly, a battery monomer, a battery, an electric device and a tab shaping device.

Background

A rechargeable battery cell, which may be referred to as a secondary battery cell, refers to a battery cell that can be continuously used by activating an active material by means of charging after the battery cell is discharged. Rechargeable battery cells are widely used in electronic devices such as mobile phones, notebook computers, battery cars, electric automobiles, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, electric tools, and the like.

The electrode assembly, which is a key component constituting a battery cell, has some problems in battery performance or safety associated with the tabs during the formation thereof.

SUMMERY OF THE UTILITY MODEL

The present application is directed to solving at least one of the problems in the prior art. To this end, an object of the present application is to provide an electrode assembly, a battery cell, a battery, a power consumption device, and a tab shaping device.

An embodiment of a first aspect of the present application provides an electrode assembly comprising: the winding structure comprises a first pole piece, a second pole piece and a diaphragm, wherein the first pole piece and the second pole piece are opposite in polarity, and the diaphragm is arranged between the first pole piece and the second pole piece; wherein, at least one in first pole piece and the second pole piece includes: a current collector; an active material layer provided at least on a surface of the current collector on a side adjacent to the separator; and the lug part is connected to one side of the current collector extending along the winding direction, the lug part comprises a continuous area close to the active material layer and an interval area far away from the active material layer, and the interval area comprises a plurality of lugs arranged at intervals along the winding direction.

In the technical scheme of this application embodiment, utmost point ear portion is equipped with continuous area and interval area, and the interval area includes a plurality of utmost point ears that arrange along the direction of convoluteing interval, and processes such as these utmost point ears accessible cross cutting form, through setting up continuous area, can make and have certain interval between utmost point ear and the mass flow body to avoid the utmost point ear to lead to the active material coating layer on the mass flow body to drop when cutting, thereby improve battery performance.

In some embodiments, in the axial direction of the winding structure, the height of the tab portion before the tab is not bent is h0, the height of the tab portion before the tab is not bent is h1, and h0 and h1 satisfy: h1/h0 is more than or equal to 0.25 and less than 1.

The height relation of the pole lug part and the pole lug disclosed in the embodiment can ensure that the thickness of a compact layer formed after the pole lug is flattened meets the welding condition, and can also improve the problem that an active substance coating layer falls off due to pole lug slitting and the problem that a diaphragm is scalded when the pole lug part is welded.

In some embodiments, 0.4 ≦ h1/h0 ≦ 0.8.

Through a large amount of experimental analysis findings of the inventor of the application, when the height relation between the lug part and the lug meets 0.4 and h1/h0 and 0.8, the requirement of the thickness of a compact layer can be better considered, the problem that the coating layer of an active substance falls off and the diaphragm is scalded during welding can be better solved, the welding and lug cutting conditions can be better met, and the preparation yield of the electrode assembly can be better.

In some embodiments, at least a portion of the tab is bent and flattened relative to the current collector, the maximum distance from the bend line to the tip of the tab is h2, the height of the tab before bending in the axial direction of the wound structure is h1, and h1 and h2 satisfy: h2/h1 is more than or equal to 0.3 and less than or equal to 1.

The size relation between the tab and the bent part disclosed in the embodiment can ensure that the thickness of a compact layer formed after the tab is flattened meets the welding condition, and can also improve the infiltration performance of the electrolyte, so that the circulation and power performance of electrolysis can be improved.

In some embodiments, the winding structure is a cylindrical winding structure, the central tube diameter of the winding structure is d, the width of the tab is l, and l and d satisfy: l/d is more than or equal to 0.7 and less than or equal to 2.

The relation between the width of the tab and the diameter of the innermost ring of the winding structure disclosed in the embodiment can ensure that the compactness of a compact layer formed after the tab is flattened meets the welding condition, and meanwhile, the loss of the optimal rate caused by the fact that the tab is folded, torn and the like when a naked electric core is wound can be avoided.

In some embodiments, the maximum distance between adjacent tabs in the tab part is g, the width of the tab is l, and l and g satisfy: g/l is less than or equal to 0.2.

The relation between the width of the lug and the distance between the lugs disclosed in the embodiment can ensure that the thickness of a compact layer formed after the lug is flattened meets the welding condition, so that the welding quality is improved.

In some embodiments, in the axial direction of the wound structure, the height h0 of the pole ear portion before the tab is unbent satisfies: h0 is more than or equal to 3mm and less than or equal to 8mm, and/or the height h1 of the tab before bending meets the following requirements: h1 is more than or equal to 1mm and less than or equal to 8mm, and/or at least part of the electrode lug is bent relative to the current collector and flattened, the maximum distance from the bending line to the top end of the electrode lug is h2, and h2 satisfies the following conditions: h2 is more than or equal to 1mm and less than or equal to 8mm.

The size design of utmost point ear portion, utmost point ear and the part of buckling disclosed in this embodiment can make utmost point ear press at ordinary times mutual overlap and form more compact layer for the obvious reduction of probability that the laser beam welded and worn makes welding quality improve, can avoid active substance layer to drop simultaneously, influence electrolyte infiltration scheduling problem.

In some embodiments, the height h0 satisfies: h0 is more than or equal to 4mm and less than or equal to 7mm, and/or the height h1 satisfies: h1 is more than or equal to 2mm and less than or equal to 7mm, and/or the distance h2 satisfies: h2 is more than or equal to 2mm and less than or equal to 7mm.

Through a large amount of experimental analysis findings of the inventor of this application, the size design of utmost point ear portion, utmost point ear and the part of buckling disclosed in this embodiment can make the compactness of the mutual overlapping formation compact layer at ordinary times of utmost point ear pressure more excellent for the reduction that the probability of laser welding was worn is showing, makes the effect in the aspect of improving welding quality, avoiding active substance layer to drop, avoiding influencing electrolyte infiltration etc. better.

In some embodiments, the tab is disposed obliquely with respect to one side edge of the current collector extending in the winding direction.

The utmost point ear of pole piece extends for the side slope of mass flow body, can further reduce the utmost point ear intensity in interval region for utmost point ear is more easily by the extrusion flattening, is favorable to improving the compactness and the thickness of the compact layer that utmost point ear formed after being flattened, improves the welding yield.

In some embodiments, the tab is inclined in a direction opposite to the winding direction. The direction that the utmost point ear slope is opposite with the direction of coiling the pole piece, and when coiling the pole piece, the utmost point ear is difficult to turn over the book, and is damaged, can improve winding structure's yield.

In some embodiments, at least a part of the tab is bent and flattened relative to the current collector, the bent part of the tab is bent by the rotary extrusion of the extrusion head, and the inclination direction of the tab is consistent with the rotation direction of the extrusion head. The direction that utmost point ear slope is unanimous with the direction of rotation of extrusion head, can avoid damaging utmost point ear when flattening, and especially winding structure outer lane and the utmost point ear of ending department can improve winding structure's yield.

In some embodiments, the inclination angle θ of the tab satisfies: theta is more than or equal to 45 degrees and less than 90 degrees. The inclination angle theta of the disclosed utmost point ear in this embodiment can effectively reduce the bending strength of utmost point ear for utmost point ear is pressed the flattening more easily, and can effectively avoid utmost point ear to roll over and damage problem at coiling and/or pressing at ordinary times.

In some embodiments, the side of the tab near the tail end at the tail end of the winding structure is provided with a beveled edge formed by corner cutting.

When the winding pole piece is cut off in the ending way, because the cutting position is unknown, the last tab in the interval area is possibly cut, so that the width is too small, and the tab at the ending part is further caused to have the problems of falling, cracking, tilting and the like.

In some embodiments, at least a portion of the beveled edge is arcuate.

Experimental analysis through the inventor of this application discovers, with the utmost point ear cross cutting formation arc hypotenuse of pole piece final phase, can avoid the utmost point ear of afterbody to appear droing, breaking, the cocking scheduling problem more effectively, further improves winding structure's yield.

Embodiments of a second aspect of the present application provide a battery cell including the electrode assembly of the above embodiments.

In some embodiments, at least a portion of the tab is bent and flattened with respect to the current collector, the maximum distance from the bend line to the tip of the tab is h2, the winding structure is a cylindrical winding structure, and the battery cell further includes: current collecting disc is located one side of cylindrical winding structure connection utmost point ear to pass through welding mode fixed connection with the part of buckling of utmost point ear, current collecting disc's thickness is t1, and t1 and h2 satisfy: t1/h2 is more than or equal to 0.05 and less than or equal to 0.2.

The relation between the height of the bent part of the tab and the thickness of the current collecting disc disclosed in the embodiment can ensure that the thickness of a compact layer formed after the tab is flattened meets the welding condition, and meanwhile, the battery capacity can be improved.

Embodiments of the third aspect of the present application provide a battery including the battery cell of the above embodiments.

An embodiment of a fourth aspect of the present application provides an electric device, which includes the battery in the above embodiment, and the battery is used for providing electric energy.

An embodiment of a fifth aspect of the present application provides a tab shaping device, which includes an extrusion head for flattening a tab in an electrode assembly according to any one of the above, so that at least a portion of the tab is bent and flattened with respect to a current collector.

In some embodiments, the tab is disposed obliquely with respect to one side edge of the current collector extending in the winding direction; the rotation direction of the extrusion head is configured to coincide with the inclination direction of the tab.

The rotating direction of the extrusion head is consistent with the direction of the inclination of the pole lug, so that the pole lug can be prevented from being damaged when being flattened, particularly the pole lug at the outer ring and the ending part of the winding structure can be prevented, and the yield of the winding structure can be improved.

The foregoing description is only an overview of the technical solutions of the present application, and the present application can be implemented according to the content of the description in order to make the technical means of the present application more clearly understood, and the following detailed description of the present application is given in order to make the above and other objects, features, and advantages of the present application more clearly understandable.

Drawings

In the drawings, like reference characters designate like or similar parts or elements throughout the several views unless otherwise specified. The figures are not necessarily to scale. It is appreciated that these drawings depict only some embodiments in accordance with the disclosure and are therefore not to be considered limiting of its scope.

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

fig. 2A is a schematic structural diagram of some embodiments of a battery according to the present disclosure;

fig. 2B is a schematic diagram of a plurality of battery cells electrically connected in some embodiments of batteries according to the present disclosure;

fig. 3 is a schematic diagram of an exploded structure of a battery cell formed in accordance with some embodiments of the battery cell of the present disclosure;

fig. 4 is a schematic cross-sectional view of a wound structure formed in accordance with some embodiments of an electrode assembly of the present disclosure;

fig. 5 is a schematic structural view of a first pole piece, a second pole piece, and a separator in some embodiments of an electrode assembly according to the present disclosure;

fig. 6 is a schematic structural view of some embodiments of an electrode assembly according to the present disclosure;

FIG. 7 is a schematic structural view of other embodiments of electrode assemblies according to the present disclosure;

FIG. 8 is an expanded schematic view of a pole piece in some embodiments of an electrode assembly according to the present disclosure;

FIG. 9 is a schematic cross-sectional view of a pole piece in some embodiments of an electrode assembly according to the present disclosure;

FIG. 10 is a schematic view of a deployment of pole pieces in other embodiments of an electrode assembly according to the present disclosure;

FIG. 11 is a schematic structural view of other embodiments of electrode assemblies according to the present disclosure;

fig. 12 is a schematic view of a deployment of pole pieces in other embodiments of an electrode assembly according to the present disclosure.

Description of reference numerals:

10A: a first pole piece; 10B: a second pole piece; 10C: a diaphragm; 100: a winding structure;

11A,11B,222: a lug portion; 12A,12B: an active material layer; 13A: an insulating layer;

17A,17B: a current collector; 14A,14B: a spacer region; 15A,15B: a continuous region;

16985A, 1697: a tab; 1000: an extrusion head; 20: a battery cell; 21: a housing assembly;

211: a housing; 212: an end cap; 22: an electrode assembly; 221: a main body portion; 23: a current collecting member;

230: a current collecting plate; 231: a welding area; 30: a battery; 31: a first case; 32: a second case;

33: an electrode terminal; 34: a bus bar; 40: a vehicle.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The following examples are merely used to more clearly illustrate the technical solutions of the present application, and therefore are only examples, and the protection scope of the present application is not limited thereby.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "including" and "having," and any variations thereof in the description and claims of this application and the description of the figures above, are intended to cover non-exclusive inclusions.

In the description of the embodiments of the present application, the technical terms "first", "second", and the like are used only for distinguishing different objects, and are not to be construed as indicating or implying relative importance or implicitly indicating the number, specific order, or primary-secondary relationship of the technical features indicated. In the description of the embodiments of the present application, "a plurality" means two or more unless specifically defined otherwise.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.

In the description of the embodiments of the present application, the term "and/or" is only one kind of association relationship describing the association object, and means that three relationships may exist, for example, a and/or B, and may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

In the description of the embodiments of the present application, the term "plurality" refers to two or more (including two), and similarly, "plural sets" refers to two or more (including two), and "plural pieces" refers to two or more (including two).

In the description of the embodiments of the present application, the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like, indicate orientations and positional relationships that are based on the orientations and positional relationships shown in the drawings, and are used for convenience in describing the embodiments of the present application and for simplification of the description, but do not indicate or imply that the device or element referred to must have a specific orientation, be configured and operated in a specific orientation, and thus, should not be construed as limiting the embodiments of the present application.

In the description of the embodiments of the present application, unless otherwise explicitly specified or limited, the terms "mounted," "connected," "fixed," and the like are to be construed broadly, e.g., as meaning fixedly connected, detachably connected, or integrated; mechanical connection or electrical connection is also possible; they may be directly connected or indirectly connected through intervening media, or may be connected through the use of two elements or the interaction of two elements. The specific meanings of the above terms in the embodiments of the present application can be understood by those of ordinary skill in the art according to specific situations.

At present, the application of power batteries is more and more extensive from the development of market conditions. The power battery is not only applied to energy storage power supply systems such as hydraulic power, firepower, wind power and solar power stations, but also widely applied to electric vehicles such as electric bicycles, electric motorcycles, electric automobiles and the like, and a plurality of fields such as military equipment and aerospace. With the continuous expansion of the application field of the power battery, the market demand is also continuously expanding.

In some related art, the electrode assembly in the cylindrical battery cell has a long tab protruding outward with respect to the end of the winding structure, the long tab continuously extending in the winding direction of the pole piece. Before welding the long tab with the current collecting disc, the long tab needs to be bent and flattened to form a structure in which the tabs are overlapped layer by layer from outside to inside. The inventor researches and discovers that the long tab has a certain curvature along with the winding of the pole piece, and the bent long tab is easy to wrinkle when being flattened, so that the tab is easy to break and damage, and the risk of pole piece short circuit caused by the insertion of wrinkles towards the pole piece is easy to affect the safety performance of the battery. Moreover, the long tab wound into a circular ring shape has high bending strength, and the deformation generated when the tab is crushed by extrusion is difficult to ensure continuity and uniformity, so that the laminated tab after being flattened is not uniform enough, has poor compactness, is easy to cause welding penetration when being welded with a current collecting disc, and has great challenges on manufacturing equipment and processes.

Based on the above consideration, the embodiment of the present disclosure provides an electrode assembly, a battery cell, a battery, an electric device and a tab shaping device, which can improve the safety performance 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 to supply power to an electric device such as a vehicle, for example, to provide a power source for operation or a power source for driving the vehicle. The battery can include box and battery module, and the box is used for providing accommodation space for the battery module, and the battery module is installed in the box. The box body can 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 power consumption device may be a mobile phone, a portable device, a notebook computer, a battery car, an electric vehicle, a ship, a spacecraft, an electric toy, an electric tool, and the like, for example, the spacecraft includes an airplane, a rocket, a space plane, a spacecraft, and the like, the electric toy includes a stationary or mobile electric toy, for example, a game machine, an electric vehicle toy, an electric ship toy, an electric airplane toy, and the like, the electric tool includes a metal cutting electric tool, an abrasive electric tool, an assembly electric tool, and an electric tool for a railway, for example, an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an electric drill impact, a concrete vibrator, and an electric planer. The embodiment of the utility model provides a do not do special restriction to above-mentioned power consumption device.

Fig. 1 is a schematic structural diagram of some embodiments of a powered device according to the present disclosure. For convenience, the electric device will be described as an example of a vehicle. Referring to fig. 1, a battery 30 is provided inside a vehicle 40, and the battery 30 is provided at the bottom or head or tail of the vehicle 40. The battery 30 supplies power to the vehicle 40, and the battery 30 serves as an operation power source of the vehicle 40, for example. The vehicle 40 may also include a controller and a motor, the controller being used to control the battery 30 to power the motor, for example, for start-up, navigation, and operational power requirements while the vehicle 40 is traveling.

In some embodiments of the present application, the battery 30 may not only serve as an operating power source for the vehicle 40, but also serve as a driving power source for the vehicle 40, instead of or in part of fuel or natural gas to provide driving power for the vehicle 40.

Fig. 2A is a schematic structural diagram of some embodiments of a battery according to the present disclosure. Fig. 2B is a schematic diagram of a plurality of battery cells electrically connected in some embodiments of batteries according to the present disclosure. Referring to fig. 2A, in some embodiments, the battery 30 includes a case and one or more battery cells 20 disposed in the case. The case body comprises a first case body 31 and a second case body 32, the first case body 31 and the second case body 32 are mutually covered, and the first case body 31 and the second case body 32 jointly define a containing space for containing the battery monomer 20. The second case 32 may be a hollow structure having an opening at one end to form a receiving cavity for receiving the battery cell 20, the first case 31 may be a plate-shaped structure, and the first case 31 covers the opening side of the second case 32, so that the first case 31 and the second case 32 together define a receiving space; the first case 31 and the second case 32 may be both hollow structures having one side opened to form a receiving cavity for receiving the battery cell 20, and the opening side of the first case 31 is covered on the opening side of the second case 32. Of course, the case 20 formed by the first case 31 and the second case 32 may have various shapes, such as a cylinder, a rectangular parallelepiped, and the like. To facilitate viewing of the plurality of battery cells 20 within the case 31, fig. 2A shows only a portion of the second case 32. Referring to fig. 2B, 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 20 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 case. 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. In fig. 2B, the electrode terminal 33 of the battery cell 20 is electrically connected to the adjacent battery cell 20 through a bus bar (buss bar) 34.

Fig. 3 is a schematic diagram of an exploded structure of a battery cell according to some embodiments of the present disclosure. As shown in fig. 3, the battery cell 20 may include a case assembly 21 and an electrode assembly 22 located within the case assembly 21. The housing assembly 21 includes a housing 211 and an end cap 212. The case 211 has a hollow structure with one side open, and the end cap 212 covers the opening of the case 211 and is hermetically connected to form a sealed space for accommodating the electrode assembly 22. Electrode assembly 22 is housed in a cavity of case 211.

The housing 211 and the end cap 212 may be separate parts, and the inner environment of the battery cell 20 is formed by covering the end cap 212 at the opening of the housing 211. Without limitation, the housing 211 and the end cap 212 may be integrated, and specifically, the housing 211 and the end cap 212 may form a common connecting surface before other components are inserted into the housing, and when it is necessary to encapsulate the inside of the battery cell 20, the end cap 212 covers the housing 211. The material of the housing 211 and the end cap 212 may be various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which is not limited in this embodiment.

It will be understood that the housing assembly is not limited to the above-described structure, and the housing assembly may have other structures, for example, the housing assembly includes a housing and two end caps, the housing has a hollow structure with two opposite open sides, and one end cap is correspondingly covered on one open side of the housing and forms a sealing connection to form a sealed space for accommodating the electrode assembly and the electrolyte.

The electrode assembly 22 may include a body part 221 and a tab part 222, the tab part 222 extending from the body part 221 such that the tab part 222 protrudes from an end of the body part 221. The electrode assembly 22 may include a positive electrode tab, a negative electrode tab, and a separator. The electrode assembly 22 may be a wound structure formed of a positive electrode tab, a negative electrode tab, and a separator by winding. The electrode assembly 22 may also be a stacked structure formed by a stacking arrangement of a positive electrode tab, a negative electrode tab, and a separator. The positive pole piece comprises a positive current collector and positive active material layers coated on two opposite sides of the positive current collector. The negative pole piece comprises a negative pole current collector and negative pole active substance layers coated on two opposite sides of the negative pole current collector. The body portion 221 is the portion of the electrode assembly 22 corresponding to the area of the pole piece coated with the active material layer, and the tab portion 222 is the portion of the pole piece not coated with the active material layer. The tab portion 222 may be divided into a positive tab portion and a negative tab portion, and the positive tab portion and the negative tab portion may be disposed at two ends of the main body portion 221, or may be disposed at one end of the main body portion 221.

As shown in fig. 3, the battery cell 20 includes, in addition to the electrode assembly 22 and the case assembly 21, an electrolyte, which is located in the case to soak the electrode assembly 22, and a current collecting member 23. The housing assembly 21 includes an electrode lead-out portion (e.g., a case, an end cap, or an electrode terminal mounted on the case or the end cap) for inputting or outputting electric power; the electrode assembly 22 is housed in the case assembly 21; the current collecting member 23 is accommodated in the case assembly 21, and the current collecting member 23 serves to connect the electrode lead-out portion of the case assembly 21 and the tab portion 222 of the electrode assembly 22 such that the tab portion 222 is electrically connected with the electrode lead-out portion. For example, in some embodiments, the current collecting member 23 may have a disk shape, referred to as a current collecting disk, to be coupled to the tab part 222 at the end of the electrode assembly 22.

Fig. 4 is a schematic cross-sectional view of a wound structure formed in accordance with some embodiments of an electrode assembly of the present disclosure. Referring to fig. 4, according to some embodiments of the present application, an electrode assembly includes: a first pole piece 10A and a second pole piece 10B of opposite polarity, and a separator 10C disposed between the first pole piece 10A and the second pole piece 10B. The first pole piece 10A, the separator 10C, and the second pole piece 10B are wound in the winding direction r and form a wound structure 100, for example, a laminated structure of the second pole piece 10B, the separator 10C, the first pole piece 10A, and the separator 10C … … formed in the radial direction of the winding mechanism 100 in fig. 4 is formed. The first pole piece 10A may be a negative pole piece or a positive pole piece, and the second pole piece 10B is a positive pole piece or a negative pole piece with a polarity opposite to that of the first pole piece 10A. The winding structure 100 may form a cylindrical winding structure after winding. Accordingly, the battery cell including the electrode assembly employs a case having a cylindrical case structure.

The battery cell 10 operates by primarily relying on metal ions to move between the positive and negative electrode plates. The material of the diaphragm 10C may be PP (polypropylene) or PE (polyethylene).

Fig. 5 is a schematic view of an arrangement of a first pole piece, a second pole piece, and a separator in some embodiments of electrode assemblies according to the present disclosure. Fig. 6 is a schematic structural view of some embodiments of an electrode assembly according to the present disclosure. Fig. 7 is a schematic structural view of other embodiments of electrode assemblies according to the present disclosure. Fig. 8 is an expanded schematic view of a pole piece in some embodiments of an electrode assembly according to the present disclosure. Fig. 9 is a schematic cross-sectional view of a pole piece in some embodiments of an electrode assembly according to the present disclosure.

Referring to fig. 5, 8 and 9, in some embodiments, at least one of the first and

second pole pieces

10A and 10B includes:

current collectors

17A,17B,

active material layers

12A,12B, and

tab portions

11A, 11B. Taking fig. 8 and 9 as an example of the first pole piece 10A, as shown in fig. 5, 8 and 9, the first pole piece 10A includes a current collector 17A, an active material layer 12A, and a tab portion 11A. Active material layer 12A is provided at least on the surface of the current collector on the side adjacent to separator 10C. Taking fig. 8 and 9 as an example of the second stage sheet 10B, as shown in fig. 5, 8 and 9, the second electrode sheet 10B includes a current collector 17B, an active material layer 12B, and a tab portion 11B. Active material layer 12B is provided at least on the surface of the current collector on the side adjacent to separator 10C.

Taking the first electrode sheet 10A as an example of a negative electrode sheet, the negative electrode sheet includes a current collector (i.e., a negative electrode current collector), an active material layer 12A (i.e., a negative electrode active material layer), and a tab portion 11A (i.e., a negative electrode tab portion). The active material layer 12A is coated on the surface of the current collector. Taking fig. 5 as an example, the negative electrode tab may further include an insulating layer 13A (e.g., a ceramic insulating layer) covering the surface of the current collector and located on the side of the active material layer 12A adjacent to the tab portion 11A. The insulating layer 13A prevents burrs on the cut edge of the anode sheet from piercing the separator and shorting with the cathode sheet.

The tab portion 11A is connected to one side edge of the current collector extending in the winding direction r. The tab portion 11A has two regions, which are a continuous region 15A close to the active material layer and a spaced region 14A distant from the active material layer, respectively, and the spaced region 14A includes a plurality of tabs 16A arranged at intervals in the winding direction r. The material of the negative electrode current collector may be copper, and the negative electrode active material layer may be graphite, silicon, or the like. In some embodiments, the tab portion 11A may be welded to the side of the current collector. The tab portion 11A may also be formed by die cutting of the current collector.

Taking the second electrode sheet 10B as an example of a positive electrode sheet, the positive electrode sheet includes a current collector (i.e., a positive electrode current collector), an active material layer 12B (i.e., a positive electrode active material layer), and a tab portion 11B (i.e., a positive electrode tab portion). The active material layer 12B is coated on the surface of the current collector.

The tab portion 11B is connected to one side edge of the current collector extending in the winding direction r. The tab portion 11B has two regions, which are a continuous region 15B close to the active material layer and a spaced region 14B distant from the active material layer, respectively, and the spaced region 14B includes a plurality of tabs 16B arranged at intervals in the winding direction r. Taking a lithium ion battery as an example, the material of the positive electrode current collector may be aluminum, and the positive electrode active material layer may be lithium cobaltate, lithium iron phosphate, ternary lithium, lithium manganate, or the like. In some embodiments, the tab portion 11B may be welded to the side of the current collector. The tab portion 11B may also be formed by die cutting of the current collector.

As shown in fig. 6 and 7, in the electrode assembly, the tab portion 11A of the first pole piece 10A and the tab portion 11B of the second pole piece 10B extend from the end of the winding structure 100, and may be bent by a pressing head and flattened, for example, by kneading or smoothing, respectively, and the flattened tab portions are welded to a current collecting member (for example, a current collecting plate 230 in fig. 7). For example, in fig. 7,

tab portions

11A and 11B are provided at both ends of the winding structure 100, and the

tab portions

11A and 11B are flattened or kneaded and then welded to the current collecting tray 230.

Referring to fig. 5 to 7, the

tab portions

11A,11B are provided with continuous areas 15A,15B and spaced

areas

14A,14B, the spaced

areas

14A,14B include a plurality of

tabs

16A,16B arranged at intervals along the winding direction r, the

tabs

16A,16B can be formed by processes such as die cutting, and by providing the continuous areas 15A,15B, a certain interval can be provided between the

tabs

16A,16B and the

current collectors

17A,17B, so as to prevent the active material coating layers on the

current collectors

17A,17B from falling off when the tabs are die cut.

Moreover, when the

tab portions

11A,11B are flattened, the bending strength of the spaced

regions

14A,14B is significantly lower than that of the continuous regions 15A,15B, so that the continuous regions 15A,15B do not have significant yielding bends when the spaced

regions

14A,14B are bent and flattened, and the end faces of the tab portions can be prevented from being too close to the separator 10C, which can cause burning of the separator 10C when the flattened

tab portions

11A,11B are welded.

Moreover, the side edges of the

pole pieces

10A and 10B extending along the winding direction r are provided with the plurality of pole lugs 16A and 16B which are arranged at intervals, so that wrinkles of the pole lugs 16A and 16B positioned at the end parts of the winding structure 100 can be reduced when the pole lugs 16A and 16B are flattened, the problems that the pole lugs 16A and 16B are broken and damaged due to the wrinkles of the pole lugs 16A and 16B, the electrode lugs 16A and 16B are convexly inserted into a pole piece layer to damage the pole piece or cause short circuit of the pole piece and the like are eliminated as much as possible, in addition, the pole lugs 16A and 16B which are arranged at intervals are mutually overlapped when being flattened can form a tighter layers, the problem of welding penetration in subsequent welding can be avoided, and the welding yield can be improved.

According to some embodiments of the present application, as shown in fig. 6, 7 and 8, the axis of the winding structure 100 is X, and in the axial direction of the winding structure 100, i.e. the extending direction of the axis X, the height of the tab portion before the tab is not bent is h0, and the height of the tab before the tab is not bent is h1, which satisfy: h1/h0 is more than or equal to 0.25 and less than 1.

For example, in some embodiments, h1/h0 may be equal to 0.25, 0.35, 0.45, 0.55, 0.65, 0.75, 0.85, or 0.95.

Of course, the numerical range of h1/h0 is not limited thereto, for example, in other embodiments, as long as h1< h0 is satisfied.

It is understood that in the electrode assembly, the final state of the tabs is bent and flattened to facilitate connection with the current collecting plate. As shown in fig. 8, the height h0 of the tab portion and the height h1 of the tab defined in the present embodiment are both the heights before the

tabs

16A,16B are not bent, and may be said to be the original heights of the tab portion and the

tabs

16A, 16B. In some embodiments, taking fig. 8 as an example, h0 and h1 can be measured before the

tabs

16A,16B of the pole piece are unbent, and in other embodiments, taking fig. 6 and 7 as an example, h0 and h1 can be measured by straightening the

tabs

11A,11B in the wound structure 100.

In the present embodiment, the size of the tab portion of at least one of the first and

second pole pieces

10A and 10B satisfies the above formula, and for example, the tab portion 11A of the first pole piece 10A may satisfy the above size, the tab portion 11B of the second pole piece 10B may satisfy the above size, or both the tab portion 11A of the first pole piece 10A and the tab portion 11B of the second pole piece 10B may satisfy the above size.

The height h0 of the lug part reflects the extension size of the lug part in the direction vertical to the side edge of the current collector; the height h1 of the tab is the height of the spacing region, and in the same way, the height h1 of the tab represents the extension size of the tab in the direction perpendicular to the side edge of the current collector.

Through research of the inventor of the application, the height of the tab in the interval area is insufficient if h1/h0 is less than 0.25, and the thickness of a compact layer formed after the tab is flattened is insufficient, so that the problems of welding and the like are easily caused; if h1/h0 is more than or equal to 1, the height of the tab is more than or equal to that of the whole tab part, an active substance coating layer is easy to fall off when the tab is cut, and a diaphragm is easy to scald when the flattened tab part is welded. The height relation of the pole lug part and the pole lug disclosed in the embodiment can ensure that the thickness of a compact layer formed after the pole lug is flattened meets the welding condition, and can also improve the problem that an active substance coating layer falls off due to pole lug slitting and the problem that a diaphragm is scalded when the pole lug part is welded.

According to some embodiments of the present application, a height h0 of the tab portion before the tab is not bent and a height h1 of the tab portion before the tab is not bent satisfy: h1/h0 is more than or equal to 0.4 and less than or equal to 0.8.

For example, in some embodiments, h1/h0 may be equal to 0.4, 0.5, 0.6, 0.7, 0.8.

According to some embodiments of the present application, at least a portion of the tab is bent and flattened with respect to the current collector, as shown in fig. 8, and the maximum distance from the bending line S to the top end (free end) of the

tab

16A,16B is h2, i.e., the height of the bent portion is h2; in the axial direction of the winding structure 100, the height of the tab before bending is h1; h1 and h2 satisfy: h2/h1 is more than or equal to 0.3 and less than or equal to 1.

For example, in some embodiments, h2/h1 may be equal to 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1.

Of course, in practical applications, the range of h2/h1 is not limited thereto, for example, in other embodiments, h2/h1 may be greater than 1, i.e., the continuous region of the pole ear portion may also exhibit yield bending.

In the present embodiment, the size of the tab portion of at least one of the first pole piece 10A and the second pole piece 10B satisfies the above formula, and for example, the tab portion 11A of the first pole piece 10A may satisfy the above size, the tab portion 11B of the second pole piece 10B may satisfy the above size, or both the tab portion 11A of the first pole piece 10A and the tab portion 11B of the second pole piece 10B may satisfy the above size.

The bent and flattened part of the tab is also used for welding with a current collecting component (such as the current collecting plate 20), and the height h2 of the bent part of the tab influences the yield of subsequent welding.

Through research of the inventor of the application, the inventor finds that if h2/h1 is less than 0.3, the height of the bent part is insufficient, so that the thickness of the formed compact layer is insufficient, the welding condition cannot be met, and the problems of welding penetration and the like are easily caused; if h2/h1 is more than 1, the height of the bent part is greater than that of the tab before bending, namely, the continuous area is also bent, the thickness of the compact layer formed by flattening cannot be obviously increased, and the electrolyte wetting performance is adversely affected because the slits between the tabs are completely compressed. The size relation between the tab and the bent part disclosed in the embodiment can ensure that the thickness of a compact layer formed after the tab is flattened meets the welding condition, and can also improve the infiltration performance of the electrolyte, so that the circulation and power performance of electrolysis can be improved.

As shown in fig. 6, according to some embodiments of the present application, the winding structure 100 is a cylindrical winding structure, the central tube diameter of the winding structure 100 is d, the arrow direction of the winding direction (r) is taken as the starting end, d is the circumferential diameter of the corresponding pole piece layer of the first pole lug of the

pole lug parts

11A and 11B along the winding direction (r) in the cylindrical winding structure 100, i.e. the minimum diameter corresponding to the pole lug at the innermost circle of the winding structure is d, the width of the pole lug is l, and l/d is greater than or equal to 0.7 and less than or equal to 2. The width l of the tab represents the dimension of the tab in the winding direction r.

For example, in some embodiments l/d may be equal to 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2.

In this embodiment, the size of the tab of at least one of the first pole piece 10A and the second pole piece 10B satisfies the above formula, for example, the tab 16A of the first pole piece 10A may satisfy the above size, the tab 16B of the second pole piece 10B may satisfy the above size, or both the tab 16A of the first pole piece 10A and the tab 16B of the second pole piece 10B may satisfy the above size.

The research of the inventor of the application discovers that if l/d is less than 0.7, the width of the tab is too small, and the tab is easy to turn over and tear when the pole piece is rolled after the tab is die-cut and when a bare cell is wound, so that the problems of high rate loss and even safety are caused; if l/d is greater than 2, the width of the tab is too large, the strength of the tab (particularly, at an inner ring and a middle ring of a naked battery cell) cannot be effectively reduced, the tightness of a compact layer formed after the tab is flattened cannot be effectively improved, and poor welding is easily caused. The relation between the width of the tab and the diameter of the innermost ring of the winding structure disclosed in the embodiment can ensure that the compactness of a compact layer formed after the tab is flattened meets the welding condition, and meanwhile, the loss of the optimal rate caused by the fact that the tab is folded, torn and the like when a naked electric core is wound can be avoided.

As shown in fig. 8, according to some embodiments of the present application, the maximum distance between adjacent tabs is g, the width of the tabs is l, and g/l is less than or equal to 0.2.

For example, in some embodiments, g/l may be equal to 0.05, 0.10, 0.15, or 0.2.

Through research of the inventor of the application, the inventor finds that when g/l is larger than 0.2, the width of the pole lugs is too small, the distance between the pole lugs is too large, the thickness of a compact layer formed after flattening is insufficient, and the welding yield is easily influenced. The relation between the width of the lug and the distance between the lugs disclosed in the embodiment can ensure that the thickness of a compact layer formed after the lug is flattened meets the welding condition, so that the welding quality is improved.

As shown in fig. 8, according to some embodiments of the present application, a height h0 of the tab portion before the tab is unbent satisfies: h0 is more than or equal to 3mm and less than or equal to 8mm, and/or the height h1 of the tab before bending meets the following requirements: h1 is more than or equal to 1mm and less than or equal to 8mm, and/or the height h2 of the bent part of the tab meets the following requirements: h2 is more than or equal to 1mm and less than or equal to 8mm.

For example, in some embodiments, h0 may be equal to 3mm, 4mm, 5mm, 6mm, 7mm, 8mm. h1 may be equal to 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm. h2 may be equal to 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm.

Through a large amount of experimental analysis findings of the inventor of this application, the size design of utmost point ear portion, utmost point ear and the part of buckling disclosed in this embodiment can make utmost point ear overlap each other and form more compact utmost point ear layer when flattening for the obvious reduction of probability that the laser beam welded through makes welding quality improve, can avoid active material coating layer to drop simultaneously, influence the problem such as electrolyte infiltration.

As shown in fig. 8, according to some embodiments of the present application, a height h0 of the tab portion before the tab is unbent satisfies: h0 is more than or equal to 4mm and less than or equal to 7mm, and/or the height h1 of the tab before bending meets the following requirements: h1 is more than or equal to 2mm and less than or equal to 7mm, and/or the height h2 of the bent part of the tab meets the following conditions: h2 is more than or equal to 2mm and less than or equal to 7mm. In this embodiment, the size of the tab portion of at least one of the first pole piece 10A and the second pole piece 10B satisfies the above formula.

For example, in some embodiments, h0 may be equal to 4mm, 5mm, 6mm, 7mm. h1 may be equal to 2mm, 3mm, 4mm, 5mm, 6mm, 7mm. h2 may be equal to 2mm, 3mm, 4mm, 5mm, 6mm, 7mm.

Through a large amount of experimental analysis findings of the inventor of the application, the size design of the lug part, the lug and the bending part disclosed in the embodiment can ensure that the compactness of the lug layer formed by mutual overlapping of the lugs during flattening is better, the probability of laser welding is obviously reduced, and the effects of improving the welding quality, avoiding the falling of an active substance coating layer, avoiding influencing the infiltration of electrolyte and the like are better.

Fig. 10 is a schematic view of a deployment of pole pieces in other embodiments of an electrode assembly according to the present disclosure. As shown in fig. 10, according to some embodiments of the present application, the

tabs

16A,16B of the

pole pieces

10A, 10B are disposed obliquely with respect to one side edge of the current collector extending in the winding direction.

In this embodiment, at least one of the tab 16A of the first pole piece 10A and the tab 16B of the second pole piece 10B is disposed in an inclined manner, for example, the tab 16A of the first pole piece 10A may be disposed in an inclined manner, the tab 16B of the second pole piece 10B may be disposed in an inclined manner, or both the tab 16A of the first pole piece 10A and the tab 16B of the second pole piece 10B may be disposed in an inclined manner.

The conventional tab extends perpendicularly relative to the side edge of the current collector, and in the embodiment of the disclosure, the tab does not extend perpendicularly but obliquely extends at an included angle relative to the side edge of the current collector. The pole lug of the pole piece extends obliquely relative to the side edge of the current collector, so that the pole lug strength of the spacing area can be further reduced, the pole lug is more easily extruded and flattened, the compactness and the thickness of a compact layer formed after the pole lug is flattened are favorably improved, and the welding yield is improved.

As shown in fig. 10, according to some embodiments of the present application, the inclination angle θ of the

tabs

16A,16B satisfies: theta is more than or equal to 45 degrees and less than 90 degrees.

For example, in some embodiments, θ may be equal to 45 °, 55 °, 65 °, 75 °, 85 °.

In the present embodiment, the inclination angle of at least one of the tab 16A of the first pole piece 10A and the tab 16B of the second pole piece 10B satisfies the above condition, for example, the inclination angle of the tab 16A of the first pole piece 10A may satisfy the above condition, the inclination angle of the tab 16B of the second pole piece 10B may satisfy the above condition, or both the inclination angles of the tab 16A of the first pole piece 10A and the tab 16B of the second pole piece 10B may satisfy the above condition.

Through a large amount of experimental analysis of the inventor of the application, the bending strength of the tab cannot be effectively reduced when the inclination angle of the tab is smaller than 45 degrees, and the tab is easy to turn over and damage. The inclination angle theta of the disclosed utmost point ear in this embodiment can effectively reduce the bending strength of utmost point ear for utmost point ear is pressed the flattening more easily, and can effectively avoid utmost point ear to roll over and damage problem at coiling and/or pressing at ordinary times.

Fig. 11 is a schematic structural view of other embodiments of electrode assemblies according to the present disclosure. As shown in fig. 11, according to some embodiments of the present application, the

pole pieces

10A, 10B have the

pole ears

16A,16B inclined in a direction opposite to the winding direction r of the

pole pieces

10A, 10B.

In the present embodiment, at least one of the tab 16A of the first pole piece 10A and the tab 16B of the second pole piece 10B is disposed obliquely and the oblique direction is opposite to the winding direction r, for example, the tab 16A of the first pole piece 10A and the tab 16B of the second pole piece 10B shown in fig. 10 are both disposed obliquely and the oblique directions are both opposite to the winding direction r.

The direction that the utmost point ear slope is opposite with the direction of coiling the pole piece, and when coiling the pole piece, the utmost point ear is difficult to turn over the book, and is damaged, can improve winding structure's yield.

As shown in fig. 11, according to some embodiments of the present application, the bent portions of the

tabs

16A,16B are bent and flattened by the rotational pressing of the pressing head 1000, the pressing head 1000 is rotated in a rotational direction o to flatten or smooth the bent portions of the

tabs

16A,16B, and the inclination direction of the

tabs

16A,16B coincides with the rotational direction o of the pressing head 1000.

In this embodiment, at least one of the tab 16A of the first pole piece 10A and the tab 16B of the second pole piece 10B is disposed obliquely with the oblique direction coinciding with the rotation direction o of the extrusion head 1000, for example, the tab 16A of the first pole piece 10A and the tab 16B of the second pole piece 10B shown in fig. 11 are both disposed obliquely with the oblique direction coinciding with the rotation direction o of the extrusion head 1000.

The direction of inclination of the

tabs

16A and 16B is consistent with the rotation direction o of the extrusion head 1000, so that the

tabs

16A and 16B can be prevented from being damaged during flattening, and particularly, the

tabs

16A and 16B at the outer ring and the ending part of the winding structure 100 can improve the yield of the winding structure 100.

In some embodiments, taking fig. 11 as an example, the extrusion head 1000 is opposite to the winding direction r of the winding structure in the rotation direction o, and the

tabs

16A,16B are inclined in the same direction as the rotation direction o of the extrusion head 1000 and opposite to the winding direction r of the winding structure. Therefore, the

tabs

16A and 16B can be prevented from being folded and damaged when the

pole pieces

10A and 10B are wound, the

tabs

16A and 16B can be prevented from being damaged when the

tabs

16A and 16B are flattened, and the yield of the winding structure can be improved.

Fig. 12 is a schematic view of a development of a pole piece in further embodiments of an electrode assembly according to the present disclosure. As shown in fig. 12, according to some embodiments of the present application, the side of the

tabs

160A, 160B near the trailing end at the end of the wound structure is provided with a beveled edge Q formed by corner cutting. For example, when the

wound pole pieces

10A and 10B are cut off at the ending, the corner of the

tab

160A and 160B at the ending near the ending is cut off directly, so that the ending of the tab forms a bevel edge Q.

In this embodiment, at least one of the tab 160A of the first pole piece 10A at the ending of the winding structure and the tab 160B of the second pole piece 10B at the ending of the winding structure is provided with an oblique edge Q, for example, the tab 160A of the first pole piece 10A at the ending of the winding structure may be provided with an oblique edge Q, the tab 160B of the second pole piece 10B at the ending of the winding structure may be provided with an oblique edge Q, or both the tab 160A of the first pole piece 10A at the ending of the winding structure and the tab 160B of the second pole piece 10B at the ending of the winding structure may be provided with an oblique edge Q.

As shown in fig. 11, when the wound pole piece is cut at the end, the

last tabs

16A and 16B in the gap region may be cut at an unknown cutting position, and the width may be too small, which may cause problems such as separation, breakage, and warping of the tabs at the end. Therefore, in the embodiment, the tab at the ending part is subjected to die cutting so that the corner part of the tail end of the tab is cut off, and the problem can be effectively solved.

As shown in fig. 12, the hypotenuse Q of the

tabs

160A, 160B at the end of the wound structure is at least partially arcuate in shape according to some embodiments of the present application. For example, in some embodiments, the corners of the

tabs

160A, 160B at the ends of the pole pieces are die cut using an arcuate cut to form the arcuate hypotenuse Q.

In this embodiment, at least one of the tab 160A of the first pole piece 10A at the ending of the winding structure and the tab 160B of the second pole piece 10B at the ending of the winding structure is provided with an arc-shaped oblique edge Q, for example, the tab 160A of the first pole piece 10A at the ending of the winding structure is provided with an arc-shaped oblique edge Q, the tab 160B of the second pole piece 10B at the ending of the winding structure is provided with an arc-shaped oblique edge Q, or the tab 160A of the first pole piece 10A at the ending of the winding structure and the tab 160B of the second pole piece 10B at the ending of the winding structure are both provided with an arc-shaped oblique edge Q.

Experimental analysis through the present application inventor discovers, with the utmost point ear cross cutting formation arc hypotenuse of pole piece ending department, can avoid the utmost point ear of afterbody to appear droing, breaking, the cocking scheduling problem more effectively, further improves winding structure's yield.

Of course, the beveled edges formed by die cutting the tab corners are not limited to being arc-shaped, and may be straight, for example.

According to some embodiments of the present disclosure, there is also provided a tab shaping device. As shown in fig. 11, the tab shaping device includes an extrusion head 1000. The extrusion head 1000 is used to flatten the

tabs

16A,16B in the electrode assembly of any of the above embodiments, so that at least portions of the

tabs

16A,16B are bent and flattened against the current collector.

According to some embodiments of the present disclosure, the bent portions of the

tabs

16A,16B are flattened by the rotational pressing of the pressing head 1000.

According to some embodiments of the present disclosure, the

tabs

16A,16B are disposed obliquely with respect to one side edge of the current collector extending in the winding direction r. As shown in fig. 11, the extrusion head 1000 is rotated in a rotation direction o to knead or smooth the bent portions of the

tabs

16A,16B, the rotation direction o of the extrusion head 1000 being configured to coincide with the inclination direction of the

tabs

16A, 16B.

The rotation direction o of the extrusion head 1000 is consistent with the inclination direction of the

tabs

16A and 16B, so that the

tabs

16A and 16B can be prevented from being damaged during flattening, particularly the

tabs

16A and 16B at the outer ring and the ending part of the winding structure 100, and the yield of the winding structure 100 can be improved.

Of course, the tab reshaping device provided by the present disclosure may further include other structures, for example, a driving mechanism for driving the extrusion head to move, which is not limited in this embodiment.

There is also provided, according to some embodiments of the present disclosure, a battery cell including the electrode assembly of any of the preceding embodiments. For example, fig. 2B is a schematic view illustrating a connection structure of a plurality of battery cells 20, wherein each battery cell 20 includes an electrode assembly according to any one of the embodiments. Or, for example, a battery cell 20 as shown in fig. 3, in which an electrode assembly 22 employs the electrode assembly of any of the foregoing embodiments. The battery unit adopting the electrode assembly has better performance, such as safer performance, higher product yield and the like.

According to some embodiments of the present application, at least a portion of the tab is bent and flattened with respect to the current collector, a maximum distance from the bend line to the tip of the tab is h2, and the winding structure is a cylindrical winding structure. The electrode assembly also comprises a current collecting disc, wherein the current collecting disc is positioned on one side of the connecting pole ear part of the cylindrical winding structure and is fixedly connected with the bent part of the pole ear in a welding mode.

For example, in fig. 7, the winding structure 100 is a cylindrical winding structure, the tab portion 13A and the tab portion 13B are respectively provided at both ends of the winding structure 100, and the tab portion 13A and the tab portion 13B are respectively bent and flattened and then welded to the current collecting plate 230. Taking the example shown in fig. 7, reference numeral 231 shows a welding region 231 on the current collecting plate 20.

As shown in fig. 7, in some embodiments, the current collecting disc 20 has a thickness t1, the bent portion of the tab has a height h2, and t1 and h2 satisfy: t1/h2 is more than or equal to 0.05 and less than or equal to 0.2.

In this embodiment, the size of the tab bent portion of at least one of the first pole piece 10A and the second pole piece 10B satisfies the above formula, for example, the size of the tab 16A bent portion of the first pole piece 10A may satisfy the above size, the size of the tab 16B bent portion of the second pole piece 10B may satisfy the above size, or both the tab 16A bent portion of the first pole piece 10A and the tab 16B bent portion of the second pole piece 10B may satisfy the above size.

Through research of the inventor of the application, if t1/h2 is less than 0.05, the height of the bent part is too large, so that the thickness of a compact layer formed after the flat pressing of the tab is too large, and the capacity of the battery is reduced; if t1/h2 is more than 0.2, the height of the bent part is too small, so that the thickness of the compact layer formed after flattening is insufficient, welding conditions are not met, and welding penetration and other problems are easily caused. The relation between the height of the bent part of the lug and the thickness of the current collecting disc disclosed in the embodiment can ensure that the thickness of a compact layer formed after the lug is flattened meets welding conditions, and meanwhile, the capacity of a battery can be improved.

As shown in fig. 2A, according to some embodiments of the present disclosure, there is also provided a battery 30 comprising the battery cell 20 according to any of the previous embodiments. The battery 30 using the battery cell 20 has better performance, such as higher safety and product yield.

As shown in fig. 1, according to some embodiments of the present disclosure, there is also provided an electric device including the battery 30 of any of the foregoing embodiments.

The electric device may be any one of the aforementioned electric devices requiring a battery, such as an electric device or an energy storage device. For example, the electric device in fig. 1 is a vehicle. The electric device adopting the battery has better performance, such as safety and reliability.

As shown in fig. 4, some embodiments of the present disclosure provide an electrode assembly including: a first pole piece 10A and a second pole piece 10B of opposite polarity, and a separator 10C disposed between the first pole piece 10A and the second pole piece 10B. The first pole piece 10A, the diaphragm 10C, and the second pole piece 10B are wound in the winding direction r to form a winding structure 100, the first pole piece 10A is a negative pole piece, and the second pole piece 10B is a positive pole piece having a polarity opposite to that of the first pole piece 10A. The winding structure 100 forms a cylindrical winding structure after winding.

As shown in fig. 5, 8 and 9, the first electrode sheet 10A includes a current collector 17A (i.e., a negative electrode current collector), an active material layer 12A (i.e., a negative electrode active material layer), and a tab portion 11A (i.e., a negative electrode tab portion), and further includes an insulating layer 13A (e.g., a ceramic insulating layer or the like) covering the surface of the current collector 17A and located on a side of the active material layer 12A adjacent to the tab portion 11A; the tab portion 11A is connected to one side of the current collector 17A extending in the winding direction r, the tab portion 11A has a continuous region 15A close to the active material layer and a spaced region 14A distant from the active material layer, and the spaced region 14A includes a plurality of tabs 16A arranged at intervals in the winding direction r.

The second electrode sheet 10B includes a current collector 17B (i.e., a positive electrode current collector), an active material layer 12B (i.e., a positive electrode active material layer), and a tab portion 11B (i.e., a positive electrode tab portion); the lug part 11B is connected to one side of the current collector 17B extending in the winding direction r. The tab portion 11B has a continuous region 15B close to the active material layer and a spacing region 14B distant from the active material layer, and the spacing region 14B includes a plurality of tabs 16B arranged at intervals in the winding direction r.

As shown in fig. 6 and 7, the tab portion 11A of the first pole piece 10A and the tab portion 11B of the second pole piece 10B respectively extend from two ends of the winding structure 100, the tab 16A of the tab portion 11A and the tab 16B of the tab portion 11B are respectively pressed and flattened by the pressing head 1000, and the flattened tab 16A and the flattened tab 16B are respectively welded to the current collecting plate 230.

The

tab portions

11A and 11B of the first and

second pole pieces

10A and 10B each satisfy the following dimensional settings: as shown in fig. 8, in the axial direction of the winding structure, the height h0 of the tab portion before the tab is not bent, the height h1 of the tab before the tab is not bent, and the height h2 of the portion of the tab portion for flattening by bending satisfy the following conditions: h0 is more than or equal to 4mm and less than or equal to h0 and less than or equal to 7mm, h1 is more than or equal to 2mm and less than or equal to h1 and less than or equal to 7mm, h2 is more than or equal to 2mm and less than or equal to h2 and less than or equal to 7mm, and h1/h0 is more than or equal to 0.25 and less than or equal to 1,0.3 and less than or equal to h2/h1 and less than or equal to 1.

As shown in fig. 10 and 11, the tab 16A of the first pole piece 10A and the tab 16B of the second pole piece 10B are both disposed in an inclined manner, and both of the inclined manners satisfy the following conditions: the inclination direction is opposite to the winding direction r of the winding structure and is consistent with the rotation direction o of the extrusion head 1000, and the inclination angle theta meets the condition that theta is more than or equal to 45 degrees and less than 90 degrees.

Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art will understand that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; these modifications and substitutions do not depart from the spirit of the embodiments of the present application, and they should be construed as being included in the scope of the claims and description of the present application. 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 application is not intended to be limited to the particular embodiments disclosed herein but is to cover all embodiments that may fall within the scope of the appended claims.

Claims

1. An electrode assembly, comprising: a first pole piece (10A) and a second pole piece (10B) with opposite polarities, and a diaphragm (10C) arranged between the first pole piece (10A) and the second pole piece (10B), wherein the first pole piece (10A), the diaphragm (10C) and the second pole piece (10B) are wound along a winding direction (r) to form a winding structure (100);

wherein at least one of the first pole piece (10A) and the second pole piece (10B) comprises:

a current collector (17A;

an active material layer (12a, 12b) provided at least on a surface of the current collector (17a, 17b) on a side adjacent to the separator (10C); and

a pole ear portion (111a.

2. The electrode assembly according to claim 1, wherein in an axial direction of the wound structure (100), a height of the tab portion (111a: h1/h0 is more than or equal to 0.25 and less than 1.

3. The electrode assembly of claim 2, wherein 0.4. Ltoreq. H1/h 0. Ltoreq.0.8.

4. The electrode assembly according to any of claims 1-3, characterized in that at least part of the tab (16911A: h2/h1 is more than or equal to 0.3 and less than or equal to 1.

5. The electrode assembly of any of claims 1-4, wherein the wound structure (100) is a cylindrical wound structure, the wound structure (100) has a central tube diameter d, the tabs (16981) have widths l, l and d satisfying: l/d is more than or equal to 0.7 and less than or equal to 2.

6. An electrode assembly according to any one of claims 1-5, characterized in that the maximum spacing between adjacent tabs (11a: g/l is less than or equal to 0.2.

7. The electrode assembly according to any one of claims 1 to 6, characterized in that, in the axial direction of the wound structure (100), a height h0 of the tab portion (11a: h0 is greater than or equal to 3mm and less than or equal to 8mm, and/or the height h1 of the tab (1698) before bending satisfies: h1 is more than or equal to 1mm and less than or equal to 8mm,

and/or at least part of the tab (1691: h2 is more than or equal to 1mm and less than or equal to 8mm.

8. The electrode assembly of claim 7, wherein the height h0 satisfies: h0 is more than or equal to 4mm and less than or equal to 7mm, and/or the height h1 satisfies: h1 is more than or equal to 2mm and less than or equal to 7mm, and/or the distance h2 satisfies: h2 is more than or equal to 2mm and less than or equal to 7mm.

9. The electrode assembly according to any of claims 1-8, characterized in that the tab (16981) is disposed obliquely with respect to one side of the current collector (17A.

10. An electrode assembly according to claim 9, characterized in that the direction of inclination of the tab (16986 a.

11. The electrode assembly according to claim 9 or 10, characterized in that at least part of the tab (16911 a.

12. The electrode assembly according to any one of claims 9-11, wherein the inclination angle θ of the tabs (16981 a: theta is more than or equal to 45 degrees and less than 90 degrees.

13. The electrode assembly according to any one of claims 1 to 12, wherein a side of the tab (160a.

14. The electrode assembly of claim 13, wherein at least a portion of the beveled edge (Q) is arcuate.

15. A battery cell, comprising: the electrode assembly of any one of claims 1-14.

16. The battery cell of claim 15,

at least part of the tab (1693A,

the winding structure (100) is a cylindrical winding structure,

the battery cell further includes: the current collecting plate (230) is positioned on one side, connected with the pole ear part (111A and 11B), of the cylindrical winding structure (100) and fixedly connected with the bent part of the pole ear (16A and 116B) in a welding mode, and the thickness of the current collecting plate (230) is t1, and t1 and h2 meet the following requirements:

0.05≤t1/h2≤0.2。

17. a battery comprising a cell according to claim 15 or 16.

18. An electric device characterized by comprising the battery according to claim 17.

19. A tab reshaping device, comprising an extrusion head (1000), the extrusion head (1000) being adapted to flatten a tab (16911 a, 16941 b) in an electrode assembly according to any of claims 1-14, such that at least a portion of the tab (16911 a, 1694 b) is bent and flattened relative to the current collector (17a.

20. The tab reshaping device according to claim 19,

said tab (1693) being arranged obliquely with respect to one side of said current collector (17A;

the direction of rotation (o) of the extrusion head (1000) is configured to coincide with the direction of inclination of the tab (16981A.