WO2024131494A1

WO2024131494A1 - Electrode assembly, battery cell, energy storage apparatus, electric device and processing method

Info

Publication number: WO2024131494A1
Application number: PCT/CN2023/135286
Authority: WO
Inventors: 张亮亮; 熊永锋
Original assignee: 厦门海辰储能科技股份有限公司
Priority date: 2022-12-22
Filing date: 2023-11-30
Publication date: 2024-06-27
Also published as: CN118248919A

Abstract

An electrode assembly of the present application comprises a first electrode sheet (101), a second electrode sheet (102) and a separator (103), wherein at least one of the first electrode sheet (101) and the second electrode sheet (102) comprises a first short edge (11) and a second short edge (12) opposite each other, and a long edge (13) connecting the first short edge (11) to the second short edge (12), wherein the long edge (13) is provided with a plurality of tabs (2).

Description

Electrode assembly, battery cell, energy storage device, electrical equipment and processing method

Priority information

This application claims priority and benefits of patent application No. 202211656454.5 filed with the State Intellectual Property Office of China on December 22, 2022, and the entire text of which is incorporated herein by reference.

Technical Field

The present application relates to the field of battery technology, and in particular to an electrode assembly, a battery cell, an energy storage device, an electrical equipment and a processing method.

Background technique

When the battery is working, electrons flow from the positive electrode tab to the negative electrode tab. In the related art, the battery is connected to only one tab on each of the positive and negative electrode tabs. After the electrons flow from the positive tab to the positive electrode tab, they need to flow along the winding direction of the positive electrode tab to the negative electrode tab first, and finally flow out of the negative tab. The electron flow path is too long, and the battery internal resistance is proportional to the length of the electron flow path and inversely proportional to the width of the electron flow path (i.e. the tab width). Therefore, the internal resistance is too large, the heat generation is more, and the output power is low.

Summary of the invention

The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes an electrode assembly, which shortens the flow path of electrons and reduces the internal resistance of the battery, thereby reducing heat generation and increasing output power.

The present application also aims to provide a battery cell having the above-mentioned battery roll core.

The present application also aims to provide an energy storage device having the above-mentioned battery cell.

The present application also aims to provide an electrical device having the above energy storage device.

The present application also aims to provide a method for processing the above-mentioned battery roll core.

According to an embodiment of the first aspect of the present application, the electrode assembly includes a first pole piece, a second pole piece and a diaphragm, at least one of the first pole piece and the second pole piece includes a first short side and a second short side relative to each other, and a long side connecting the first short side and the second short side, and a plurality of pole ears are provided on the long side, and the first pole piece, the diaphragm and the second pole piece are wound into a winding body wrapped in layers, the first short side is located at the innermost layer of the winding body, and the second short side is located at the outermost layer of the winding body, and the plurality of pole ears are folded toward the axis of the winding body and adjacent pole ears partially overlap.

According to the electrode assembly of the present application, a plurality of The plurality of pole ears are folded toward the axial direction of the winding body, and two adjacent pole ears are partially in contact, so that there is no gap between the pole ears on the end face of the motor assembly. When the pole ears are welded to the collector plate, the laser will not hit the gap, which improves the welding effect. The laser is not easy to penetrate the interior of the electrode assembly and damage the electrode assembly.

According to some embodiments of the present application, the dimension of the pole ear in the direction from the first short side to the second short side is the width of the pole ear, and the widths of multiple pole ears gradually increase from the first short side to the second short side, so as to improve the folding efficiency of the pole ear toward the axis of the winding body when the diameter of the winding body becomes larger.

According to some embodiments of the present application, the dimension of the pole ear from the first short side to the second short side is the width of the pole ear, the ratio W/L of the sum of the widths W of the multiple pole ears to the length L of the long side is in the range of 0.8 to 0.98, and the ratio D/L of the sum of the spacings D between adjacent pole ears to the length L of the long side is in the range of 0.02 to 0.2. On the one hand, the pole ear has a larger width, which increases the flow area and reduces the internal resistance of the battery; on the other hand, a smaller gap exists between adjacent pole ears, which not only prevents scratches between adjacent pole ears, but also allows the pole ears at the ends of the electrode assembly to be partially in contact with each other when the pole ears are folded and moved toward the center of the electrode assembly after the pole sheet is wound into an electrode assembly. In this way, when the pole ear is welded to the collecting plate, the laser is not easy to hit the gap between the adjacent pole ears, thereby ensuring the welding effect and reducing the probability of the laser penetrating the core and causing damage to the inside of the core.

According to some embodiments of the present application, a first chamfer is formed at the connection between the pole ear and the long side, and the radius of the first chamfer is 0.02mm-1mm. By setting the first chamfer with a radius of 0.02mm-1mm at the connection between the pole ear and the long side, the roller pressure required to flatten the pole ear is reduced, so that when flattening the pole ear, the pole piece is not easily deformed, and the yield rate of electrode assembly processing is improved.

According to some embodiments of the present application, the pole ear has two second edges arranged opposite to each other and a first edge connected between the two second edges, the two second edges are connected to the long edges, the first edge is parallel to the long edge, the second edge is perpendicular to the first edge or the second edge is inclined relative to the long edge to facilitate the cutting and processing of the pole ear.

According to some embodiments of the present application, the angle between the second edge and the long side is 75 to 85 degrees, which reduces the roller pressure required for folding the tab and facilitates the folding of the tab.

According to some embodiments of the present application, the pole piece includes a first pole piece and a second pole piece, and the first pole piece and the second pole piece are both provided with pole ears, the pole ear on the first pole piece is the first pole ear, and the pole ear on the second pole piece is the second pole ear, and the first pole ear and the second pole ear are located at the axial ends of the winding body. By providing a plurality of first pole ears and a plurality of second pole ears, a plurality of parallel flow paths are formed between the first pole piece and the second pole piece, and the electrons flowing out of the first pole ear can flow along the first pole piece. The electrons flow in the width direction toward the second pole ear, further reducing the flow path of electrons, thereby further reducing the internal resistance of the battery, reducing heat generation and increasing output power.

The battery cell according to the embodiment of the second aspect of the present application includes a shell having an opening; an electrode assembly, which is the electrode assembly in the above embodiment and is accommodated in the shell; and a top cover, which covers the opening to cover the electrode assembly in the shell.

According to the battery cell of the embodiment of the present application, by adopting the above-mentioned electrode assembly, the internal resistance of the battery is reduced, the heat generation is reduced, and the output power is improved.

The energy storage device according to the embodiment of the third aspect of the present application includes the battery cell in the above embodiment.

According to the energy storage device of the embodiment of the present application, by adopting the above-mentioned battery monomer, the internal resistance of the energy storage device is reduced, the heat generation is reduced, and the output power is improved.

The electrical equipment according to the embodiment of the fourth aspect of the present application includes the energy storage device in the above embodiment, and the energy storage device is used to supply power to the electrical equipment.

According to the electrical equipment of the embodiment of the present application, by adopting the above-mentioned energy storage device, the heat generation of the electrical equipment is reduced and the output power is improved.

According to the fifth aspect of the present application, a method for processing an electrode assembly includes the following steps:

The active material is coated on a part of the surface of the current collector so that a coated area and a non-coated area are formed on the current collector;

A plurality of fine slits are cut on the non-coated area, and the fine slits separate the non-coated area into a plurality of pole ears, so that the current collector is made into a pole piece;

The pole piece and the diaphragm are stacked and then wound to form a winding body, and the pole ear is located at one axial end of the winding body;

The pole tabs are folded and flattened on one axial side of the winding body, and a plurality of pole tabs are folded toward the axis of the winding body and adjacent pole tabs are partially overlapped.

According to the processing method of the electrode assembly of the embodiment of the present application, by forming a coated area and a non-coated area on the current collector, cutting and forming a plurality of fine slits on the non-coated area, the fine slits separate the non-coated area into a plurality of pole ears, and making the current collector into a pole piece, so that after the pole piece is wound, the pole ear located at the end of the winding body can shorten the flow path of electrons on the pole piece, thereby shortening the overall flow path of electrons, reducing the internal resistance of the flow path, reducing heat generation, and improving the output power. At the same time, the plurality of pole ears are folded toward the axial direction of the electrode assembly and flattened so that two adjacent pole ears are partially in contact, so that there is no gap between the pole ears on the end face of the battery roll core, and when the pole ears are welded to the collector plate, the laser will not hit the gap, thereby improving the welding effect, and the laser is not easy to penetrate the interior of the electrode assembly, and is not easy to damage the electrode assembly.

Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a first schematic diagram of an electrode piece in an electrode assembly according to an embodiment of the present application;

FIG2 is a second schematic diagram of an electrode piece in an electrode assembly according to an embodiment of the present application;

FIG3 is a schematic diagram of an electrode assembly before winding according to an embodiment of the present application;

FIG4 is a third schematic diagram of an electrode piece in an electrode assembly according to an embodiment of the present application;

FIG5 is a fourth schematic diagram of an electrode piece in an electrode assembly according to an embodiment of the present application;

FIG6 is a schematic diagram of an end portion of an electrode assembly after winding according to an embodiment of the present application;

FIG7 is a schematic diagram of a battery cell according to an embodiment of the present application;

FIG8 is a schematic diagram of an energy storage device according to an embodiment of the present application;

FIG. 9 is a schematic diagram of an electrical device according to an embodiment of the present application.

Detailed ways

The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeat reference numbers and/or letters in different examples. This repetition is for the purpose of simplification and clarity, and does not indicate the relationship between the various embodiments and/or settings discussed in itself. In addition, the various specific processes and examples of materials provided by the present application, but those of ordinary skill in the art can appreciate the applicability of other processes and/or the use of other materials.

The electrode assembly 200 , the battery cell 300 , the energy storage device 400 , the electrical equipment 500 , and the processing method according to the embodiments of the present application are described below with reference to the accompanying drawings.

As shown in Figures 1 and 3, the electrode assembly 200 according to the embodiment of the first aspect of the present application includes a first pole piece 101, a second pole piece 102 and a diaphragm 103, at least one of the first pole piece 101 and the second pole piece 102 includes a first short side 11 and a second short side 12 relative to each other, and a long side 13 connecting the first short side 11 and the second short side 12, and a plurality of pole ears 2 are provided on the long side 13, the first pole piece 101, the diaphragm 103 and the second pole piece 102 are wound into a winding body wrapped in layers, the first short side 11 is located at the innermost layer of the winding body, the second short side 12 is located at the outermost layer of the winding body, and the plurality of pole ears 2 are folded toward the axis of the winding body and adjacent pole ears partially overlap.

Specifically, as shown in Figures 1 and 3, the electrode assembly 200 in the embodiment of the present application is composed of a first electrode sheet 101, a diaphragm 103 and a second electrode sheet 102 wound into a layered winding body, and the diaphragm 103 is arranged between the first electrode sheet 101 and the second electrode sheet 102 to separate the first electrode sheet 101 from the second electrode sheet 102 to prevent the positive electrode from contacting the negative electrode and causing a short circuit. The first pole piece 101 and the second pole piece 102 are both pole pieces 100. As shown in Figure 1, at least one pole piece 100 includes a pole piece body 1 and a pole ear 2. The pole piece body 1 includes a first short side 11 and a second short side 12 relative to each other, and a long side 13 connecting the first short side 11 and the second short side 12. A plurality of pole ears 2 are provided on the long side 13. The plurality of pole ears 2 are arranged in sequence along the length direction of the pole piece body 1, and there is a spacing between two adjacent pole ears 2. The first pole piece 101, the diaphragm 103 and the second pole piece 102 are wound into a winding body wrapped in layers. The first short side 11 is located at the innermost layer of the winding body, and the second short side 12 is located at the outermost layer of the winding body. The plurality of pole ears 2 are folded toward the axis of the winding body and adjacent pole ears partially overlap. By setting a plurality of pole ears 2 on the long side 13 of the pole body 1 of at least one pole piece 100, after the electrons flow from the first pole ear 1011 into the first pole piece 101, they can flow to the second pole ear 1021 which is closer, thus shortening the flow path of the electrons on the first pole piece 101, thereby shortening the overall flow path of the electrons, reducing the internal resistance of the flow path, reducing heat generation, and improving the output power. At the same time, the plurality of pole ears 2 are bent toward the axial direction of the electrode assembly 200, and two adjacent pole ears 2 are partially in contact, so that there is no gap between the pole ears 2 on the end face of the electrode assembly 200. When the pole ears 2 are welded to the collector plate, the laser will not hit the gap, thereby improving the welding effect, and the laser is not easy to penetrate the inside of the electrode assembly 200, and it is not easy to damage the electrode assembly 200.

Therefore, according to the electrode assembly 200 of the present application, by setting a plurality of pole ears 2 on the long side 13 of at least one of the first pole piece 101 and the second pole piece 102, after the electrons flow from the pole ears 2 on the first pole piece 101 into the first pole piece 101, they can flow to the pole ears 2 on the second pole piece 102 that are closer, thus shortening the flow path of the electrons on the first pole piece 101, thereby shortening the overall flow path of the electrons, reducing the internal resistance of the flow path, reducing heat generation, and improving the output power. At the same time, the plurality of pole ears 2 are bent toward the axial direction of the electrode assembly 200, and two adjacent pole ears 2 are partially in contact, so that there is no gap between the pole ears 2 on the end face of the electrode assembly 200, and when the pole ears 2 are welded to the collector plate, the laser will not hit the gap, thereby improving the welding effect, and the laser is not easy to penetrate the inside of the electrode assembly 200, and it is not easy to damage the electrode assembly 200.

In some embodiments, the separator 103 is made of a non-conductive material, and the separator 103 has the function of allowing electrolyte ions to pass through. In some embodiments of the present application, the dimension of the pole tab 2 in the direction from the first short side 11 to the second short side 12 is the width of the pole tab 2, and the width of the plurality of pole tabs 2 gradually increases from the first short side 11 to the second short side 12, so as to improve the folding efficiency of the pole tab 2 toward the axis of the winding body when the diameter of the winding body increases.

In some embodiments, as shown in FIG. 1 , FIG. 2 , FIG. 4 and FIG. 5 , the distance between two adjacent pole tabs 2 gradually increases from the first short side 11 to the second short side 12 , so as to ensure that the adjacent pole tabs 2 partially overlap. The number of tabs 2 to be set is reduced, thereby improving production efficiency.

In some embodiments of the present application, as shown in FIG. 1 , the dimension of the pole ear 2 from the first short side 11 to the second short side 12 is the width of the pole ear 2, and the ratio W/L of the sum of the widths W of the plurality of pole ears 2 to the length L of the pole piece body 1 is in the range of 0.8 to 0.98, and the ratio D/L of the sum of the spacings D between adjacent pole ears 2 to the length L of the long side 13 of the pole piece body 1 is in the range of 0.02 to 0.2. On the one hand, the pole ear 2 has a larger width, which increases the flow area and reduces the internal resistance of the battery; on the other hand, as As shown in FIG6 , there is a small gap between adjacent pole ears 2, which not only prevents the adjacent pole ears 2 from being scratched, but also enables the adjacent pole ears 2 to partially contact each other when the pole ear 2 at the end of the electrode assembly 200 is bent and moved toward the center of the electrode assembly 200 after the pole piece body 1 is wound into the electrode assembly 200. In this way, when the pole ear 2 is welded to the collecting plate, the laser is not easy to hit the gap between the adjacent pole ears 2, thereby ensuring the welding effect and reducing the probability of the laser penetrating the electrode assembly 200 and causing damage to the inside of the electrode assembly 200.

In some embodiments of the present application, a first chamfer is formed at the connection between the pole ear 2 and the long side 13 of the pole piece body 1, and the radius of the first chamfer is 0.02mm-1mm. By setting a first chamfer with a radius of 0.02mm-1mm at the connection between the pole ear 2 and the long side 13 of the pole piece body 1, the roller pressure required to flatten the pole ear 2 is reduced, so that when the pole ear 2 is flattened, the pole piece body 1 is not easily deformed, and the yield rate of the electrode assembly 200 is improved. The radius of the first chamfer can be any value between 0.02mm-1mm, for example, it can be 0.02mm, 0.04mm, 0.05mm, 0.07mm, 0.08mm, or 1mm, etc.

In some embodiments of the present application, as shown in FIG1 , the pole lug 2 has two second edges 22 arranged opposite to each other and a first edge 21 connected between the two second edges 22 , the two second edges 22 are connected to the long side 13 of the pole piece body 1 , the first edge 21 is parallel to the long side 13 , and the second edge 22 is perpendicular to the first edge 21 . At this time, the pole lug 2 is a rectangle, as shown in FIGS. 1 and 2 , or the second edge 22 is inclined relative to the long side 13 , as shown in FIGS. 4 and 5 . At this time, the pole lug 2 is a parallelogram. By setting the pole lug 2 to a rectangle or a parallelogram, the cutting and processing of the pole lug 2 is facilitated.

According to some embodiments of the present application, as shown in FIG. 4 and FIG. 5 , the angle between the second edge 22 and the long side 13 is 75 to 85 degrees, which reduces the roller pressure required for folding the tab 2 and facilitates the folding of the tab 2 .

Preferably, as shown in Fig. 4, the angle between the second edge 22 and the long side 13 is 80 degrees. Of course, it is understandable that the angle between the second edge 22 and the long side 13 can also be other values between 75 degrees and 85 degrees, for example, 77 degrees, 79 degrees, 81 degrees, 83 degrees, or 85 degrees as shown in Fig. 5.

In some embodiments of the present application, as shown in FIG. 3 and FIG. 6 , the pole piece 100 includes a first pole piece 101 and a second pole piece 102. The first pole piece 101 and the second pole piece 102 are both provided with a pole ear 2. The pole ear 2 on the first pole piece 101 is a first pole ear 1011, and the pole ear 2 on the second pole piece 102 is a second pole ear 1021. The first pole ear 1011 and the second pole ear 1021 are located at The axial ends of the winding body. By providing a plurality of first pole tabs 1011 and a plurality of second pole tabs 1021, a plurality of parallel flow paths are formed between the positive pole sheet 101 and the negative pole sheet 102, which further reduces the internal resistance of the battery, reduces heat generation, and improves output power.

In some embodiments, the plurality of first electrode tabs 1011 and the plurality of second electrode tabs 1021 are disposed opposite to each other at two axial ends of the electrode assembly 200 to minimize the flow path of electrons.

Of course, the present application is not limited thereto; in other embodiments, the plurality of first pole tabs 1011 and the plurality of second pole tabs 1021 may not be arranged opposite to each other at the axial ends of the electrode assembly 200. For example, the orthographic projections of a corresponding first pole tab 1011 and a corresponding second pole tab 1021 on the cross section of the electrode assembly 200 may partially overlap, which facilitates the winding of the electrode assembly 200 and reduces the processing requirements.

As shown in Figure 7, the battery cell 300 according to the second embodiment of the present application includes a shell 201, the electrode assembly 200 in the above embodiment and a top cover 202, the shell 201 has an opening, the electrode assembly 200 is accommodated in the shell 201, and the top cover 202 covers the opening to cover the electrode assembly 200 in the shell 201.

According to the battery cell 300 of the embodiment of the present application, by adopting the above-mentioned electrode assembly 200, the internal resistance of the battery is reduced, the heat generation is reduced, and the output power is improved.

As shown in FIG. 8 , the energy storage device 400 according to the third embodiment of the present application includes the battery cell 300 in the above embodiment.

According to the energy storage device 400 of the embodiment of the present application, by adopting the above-mentioned battery cell 300, the internal resistance of the energy storage device 400 is reduced, the heat generation is reduced, and the output power is improved.

Specifically, as shown in Fig. 8, the energy storage device 400 may include a battery box 301, on which a plurality of battery cells 300 are mounted and arranged to achieve intensive arrangement of the battery cells 300. When the energy storage device 400 includes a plurality of battery cells 300, and each battery cell 300 adopts the above structure, the heat generation of the energy storage device 400 is reduced and the output power is increased.

As shown in FIG. 9 , the electrical equipment 500 according to the fourth embodiment of the present application includes the energy storage device 400 in the above embodiment, and the energy storage device 400 is used to supply power to the electrical equipment 500 .

In the present application scheme, the structure of the electrical equipment 500 is not limited. For example, the electrical equipment 500 can be a mobile device such as a vehicle, a ship, a small aircraft, etc., which includes a power source, and the power source includes the above-mentioned energy storage device 400. The electric energy provided by the energy storage device 400 provides driving force for the electrical equipment 500. The mobile device can be a pure electric device, that is, the driving force of the electrical equipment 500 is all electric energy, and the power source only includes the energy storage device 400. The mobile device can also be a hybrid power device, and the power source includes the energy storage device 400 and other power devices such as an engine. Taking the vehicle shown in Figure 9 as an example, in some embodiments, the electrical equipment 500 is a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid vehicle, an extended-range vehicle, an electric tricycle or a two-wheeled electric vehicle, etc.

For another example, the electrical equipment 500 is an energy storage device such as an energy storage cabinet, which can be used as a charging cabinet for mobile devices or as an energy storage device for other devices. For example, solar power generation equipment can be equipped with an energy storage cabinet, and the electric energy generated by solar power generation is temporarily stored in the energy storage cabinet to power devices such as street lights and bus stops. According to the electrical equipment 500 of the embodiment of the present application, by adopting the above-mentioned energy storage device 400, the heat generation of the electrical equipment 500 is reduced and the output power is increased.

The pole tabs are folded and flattened on one axial side of the winding body, and the plurality of pole tabs are folded toward the axis of the winding body and adjacent pole tabs are partially overlapped.

In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

In the present application, unless otherwise clearly specified and limited, a first feature "on" or "under" a second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. The features “above”, “above” and “above” may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The features “below”, “below” and “below” of the first feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

An electrode assembly comprises a first electrode sheet (101), a second electrode sheet (102) and a diaphragm (103), wherein:

At least one of the first pole piece (101) and the second pole piece (102) comprises a first short side (11) and a second short side (12) opposite to each other, and a long side (13) connecting the first short side (11) and the second short side (12), wherein a plurality of pole ears (2) are provided on the long side (13);

The first pole piece (101), the diaphragm (103) and the second pole piece (102) are wound into a wound body wrapped in layers, the first short side (11) is located at the innermost layer of the wound body, and the second short side (12) is located at the outermost layer of the wound body;

The plurality of pole tabs (2) are folded toward the axis of the winding body and adjacent pole tabs (2) partially overlap.
The electrode assembly according to claim 1, wherein:

The dimension of the pole lug (2) in the direction from the first short side (11) to the second short side (12) is the width of the pole lug (2), and the widths of the plurality of pole lugs (2) gradually increase in the direction from the first short side (11) to the second short side (12).
The electrode assembly according to claim 1, wherein the dimension of the electrode tab (2) from the first short side (11) to the second short side (12) is the width of the electrode tab (2), the ratio W/L of the sum of the widths W of the plurality of electrode tabs (2) to the length L of the long side (13) is in the range of 0.8 to 0.98, and the ratio D/L of the sum of the spacings D between adjacent electrode tabs (2) to the length L of the long side (13) is in the range of 0.02 to 0.2.
The electrode assembly according to claim 1, wherein a first chamfer is formed at a connection between the electrode tab (2) and the long side (13), and a radius of the first chamfer is 0.02 mm-1 mm.
The electrode assembly according to claim 1, wherein the electrode tab (2) has two second edges (22) arranged opposite to each other and a first edge (21) connected between the two second edges (22), and the two second edges (22) are connected to the long side;

The first edge (21) is parallel to the long side, the second edge (22) is perpendicular to the first edge (21), or the second edge (22) is inclined relative to the long side (13).
The electrode assembly according to claim 5, wherein the second edge (22) and the long side (13) The angle is 75 to 85 degrees.
The electrode assembly according to any one of claims 1 to 6, wherein the pole piece (100) comprises a first pole piece (101) and a second pole piece (102), and the pole ear (2) is provided on both the first pole piece (101) and the second pole piece (102);

The pole lug (2) on the first pole piece (101) is a first pole lug (1011), and the pole lug (2) on the second pole piece (102) is a second pole lug (1021). The first pole lug (1011) and the second pole lug (1021) are located at two axial ends of the winding body.
A battery cell, comprising:

A housing (201), wherein the housing (201) has an opening;

An electrode assembly (200), the electrode assembly (200) being the electrode assembly (200) according to any one of claims 1 to 7, and the electrode assembly (200) being accommodated in the shell (201);

A top cover (202) covers the opening to cover the electrode assembly (200) in the shell (201).
An energy storage device, comprising the battery cell (300) according to claim 8.
An electrical device, comprising the energy storage device (400) according to claim 9, wherein the energy storage device is used to supply power to the electrical device.
A method for processing an electrode assembly, comprising the following steps:

coating the active material on a portion of the surface of the current collector so that a coating area and a non-coating area are formed on the current collector;

Cutting a plurality of slits on the non-coated area, wherein the slits separate the non-coated area into a plurality of pole ears, so that the current collector is made into a pole piece;

The pole piece and the diaphragm are stacked and then wound to form a winding body, wherein the pole ear is located at one axial end of the winding body;

The pole tabs are folded and flattened on one axial side of the winding body, and a plurality of the pole tabs are folded toward the axis of the winding body and adjacent pole tabs are partially overlapped.