CN113795939A

CN113795939A - Electrode assembly and battery cell

Info

Publication number: CN113795939A
Application number: CN202080034556.6A
Authority: CN
Inventors: 幸定清; 张政
Original assignee: Ningde Amperex Technology Ltd
Current assignee: Ningde Amperex Technology Ltd
Priority date: 2020-03-31
Filing date: 2020-03-31
Publication date: 2021-12-14
Also published as: WO2021195910A1

Abstract

The application discloses electrode subassembly and electricity core includes: a first pole piece; the polarity of the second pole piece is opposite to that of the first pole piece; the isolation film is arranged between the first pole piece and the second pole piece; the first pole piece, the second pole piece and the isolating film are stacked and then wound from two ends to the middle to form a first battery cell unit and a second battery cell unit; the first tab is arranged on the first tab and extends out of the first battery cell unit; and the second tab is arranged on the second pole piece and extends out of the second battery cell unit. The electrode assembly and the battery cell are wound from two ends to the middle through the superposed first pole piece, the superposed second pole piece and the superposed isolating film to form a first battery cell unit and a second battery cell unit, and the first battery cell unit and the second battery cell unit share the first lug and the second lug, so that the energy density, the multiplying power performance and the charging and discharging speed are improved.

Description

Electrode assembly and battery cell

Technical Field

The application relates to the field of batteries, in particular to an electrode assembly and a battery cell comprising the same.

Background

At present, foldable flexible devices are gradually becoming research hotspots, and the traditional battery structure is limited by a cubic structure and cannot meet the application of the flexible devices. At present, one or more naked electric cores are applied to the flexible device, but a plurality of naked electric cores need to be led out a plurality of tabs, so that the battery core is not beneficial to the infiltration of electrolyte, the polarization of the battery core is large, and the multiplying power performance and the charging and discharging speed of the battery core are reduced.

Disclosure of Invention

In view of the above, it is desirable to provide an electrode assembly and a battery cell with good rate capability for flexible devices.

An embodiment of the present application provides an electrode assembly including:

a first pole piece;

a second pole piece having a polarity opposite to the polarity of the first pole piece; and

a separator disposed between the first and second pole pieces;

the first pole piece, the second pole piece and the isolating film are stacked and then wound from two ends to the middle to form a first battery cell unit and a second battery cell unit;

the electrode assembly further includes:

the first tab is arranged on the first tab and extends out of the first battery cell unit; and

and the second tab is arranged on the second pole piece and extends out of the second battery cell unit.

According to some embodiments of the present application, a distance L between an axis of symmetry of the first or second pole lug parallel to a first direction and an axis of symmetry of the first pole piece parallel to the first direction satisfies: l is more than or equal to 0 and less than or equal to W/2-z/2, z is the width of the first pole piece or the second pole piece, W is the width of the first pole piece or the second pole piece, and the first direction is the length direction of the first pole piece.

According to some embodiments of the present application, the first tab extends in a direction parallel to a direction of the first cell unit away from the second cell unit; the extending direction of the second tab is parallel to the direction of the second battery cell unit departing from the first battery cell unit.

According to some embodiments of the present application, the first pole piece comprises:

a first current collector comprising opposing first and second faces;

a first active layer disposed on the first and second faces, respectively;

a first empty foil area is arranged on the first surface, and the first tab is arranged on the first current collector exposed out of the first empty foil area;

the second pole piece includes:

a second current collector comprising opposing third and fourth faces;

a second active layer disposed on the third surface and the fourth surface, respectively;

and a second empty foil area is arranged on the third surface, and the second pole lug is arranged on the second current collector exposed out of the second empty foil area.

According to some embodiments of the present application, a portion of the first tab is welded to the first current collector with a weld area proximate to the first active layer; and the part of the second lug is welded on the second current collector, and the welding area is close to the second active layer.

According to some embodiments of the present application, a plurality of third empty foil areas exposing the first current collector are arranged on the first surface at intervals; a plurality of fourth empty foil areas exposing the second current collector are arranged on the third surface at intervals; the third empty foil area and the fourth empty foil area are located in a connection area of the first battery cell unit and the second battery cell unit, and the third empty foil area and the fourth empty foil area are correspondingly arranged and located on two sides of the first pole piece and the second pole piece, which are opposite to each other.

According to some embodiments of the present application, the isolation film comprises a first isolation film, a second isolation film, and a third isolation film; the first isolating film, the first pole piece, the second isolating film, the second pole piece and the third isolating film are sequentially superposed; and the first isolating films and the second isolating films are arranged in a staggered mode, and projection contact or partial overlapping is carried out, so that the first pole piece and the second pole piece in the first battery cell unit and the second battery cell unit are isolated.

According to some embodiments of the present application, the first tab is made of nickel, and the second tab is made of aluminum.

The application still provides a battery cell, including air pocket and above-mentioned electrode subassembly, electrode subassembly set up in the air pocket, first utmost point ear with the second utmost point ear stretch out in outside the air pocket.

According to some embodiments of the present disclosure, the cell further includes an electrolyte, the electrolyte permeating into the first cell unit and the second cell unit along a second direction, the second direction being parallel to a width direction of the first pole piece.

The first pole piece, the second pole piece and the isolating film which are superposed are wound from two ends to the middle to form a first battery cell unit and a second battery cell unit, and the first battery cell unit and the second battery cell unit share the first pole lug and the second pole lug, so that the energy density, the multiplying power performance and the charging and discharging speed are improved.

Drawings

Fig. 1 is a schematic structural diagram of a battery cell according to an embodiment of the present application.

Fig. 2 is a schematic structural diagram of the battery cell shown in fig. 1 when the air bag is opened.

Fig. 3 is a schematic structural diagram of the first cell unit and the second cell unit formed by winding the cell shown in fig. 1.

Fig. 4 is a schematic structural diagram of an electrode assembly in the battery cell shown in fig. 1 according to another embodiment.

Fig. 5 is a schematic structural diagram of a first pole piece of a battery cell according to an embodiment of the present application.

Fig. 6 is a schematic structural view of the first pole piece shown in fig. 1 and provided with a first tab.

Fig. 7 is a schematic structural diagram of a second pole piece of a battery cell according to an embodiment of the present application.

Fig. 8 is a schematic structural diagram of the cell shown in fig. 1 when the first pole piece, the second pole piece and the separation film are stacked.

Fig. 9 is a schematic winding diagram of the first pole piece, the second pole piece and the separation film in the battery cell shown in fig. 8.

Fig. 10 is a schematic structural diagram of a connection region of a first cell unit and a second cell unit in the battery cell shown in fig. 2.

Description of the main elements

Battery cell 200

Air bag 201

Electrode assembly 100, 100a

First pole piece 10

Symmetry axis 1001

First current collector 11

First side 111

First empty foil zone 1111

Third empty foil region 1113

Second surface 113

First active layer 13

Second pole piece 20

Second current collector 21

Third surface 211

Second empty foil region 2111

Fourth empty foil region 2113

Fourth surface 213

Second active layer 23

Isolation diaphragm 30

First separator film 31

Second isolation film 33

Third separator 35

First tab 40

Axis of symmetry 401

First extreme position 403

Second extreme position 405

Welding area 4001

Second tab 50

First cell unit 101

Second cell unit 103

First direction X

Second direction Y

Third direction Z

The following detailed description will further illustrate the present application in conjunction with the above-described figures.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

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 in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

Some embodiments of the present application provide an electrode assembly including:

a first pole piece;

a separator disposed between the first and second pole pieces;

According to the electrode assembly, the first pole piece, the second pole piece and the isolating film which are overlapped are wound from two ends to the middle to form the first battery cell unit and the second battery cell unit, and the first battery cell unit and the second battery cell unit share the first lug and the second lug, so that the energy density, the multiplying power performance and the charging and discharging speed are improved.

Some embodiments of the present application will be described in detail below with reference to the accompanying drawings. The embodiments described below and the features of the embodiments can be combined with each other without conflict.

Referring to fig. 1, fig. 2 and fig. 3, an embodiment of the present disclosure provides a battery cell 200. The battery cell 200 includes an air bag 201 and an electrode assembly 100. The electrode assembly 100 is disposed within the gas pouch 201. The electrode assembly 100 includes a first pole piece 10, a second pole piece 20, a separator 30, a first tab 40, and a second tab 50. The polarities of the first pole piece 10 and the second pole piece 20 are opposite. For example, the polarity of the first pole piece 10 is an anode, and the polarity of the second pole piece 20 is a cathode. The first tab 40 is made of nickel, and the second tab 50 is made of aluminum.

The separator 30 is disposed between the first pole piece 10 and the second pole piece 20. After the first pole piece 10, the second pole piece 20, and the separation film 30 are stacked, the first cell unit 101 and the second cell unit 103 are formed by winding from two ends to the middle. As shown in fig. 1, both ends are wound clockwise, but not limited thereto. For example, in other embodiments, both ends may be wound counterclockwise at the same time. The first tab 40 is disposed on the first pole piece 10 and extends outward from the first cell unit 101. The second tab 50 is disposed on the second pole piece 20 and extends outward of the second battery cell unit 103. The first tab 40 and the second tab 50 extend out of the air bag 201.

Above-mentioned electrode assembly 100 and electric core 200 constitute the unit of naked electric core through two of the first electric core unit 101 of coiling shaping and second electric core unit 103, and electrode assembly 100 only sets up one first utmost point ear 40 and one second utmost point ear 50, two units that constitute naked electric core share one first utmost point ear 40 and one second utmost point ear 50 improves multiplying power performance and charge-discharge speed.

Referring to fig. 5 and fig. 6, for clarity of the following description, a first direction X is defined as a length direction of the first pole piece 10, a second direction Y is a width direction of the first pole piece 10, and a third direction Z is a thickness direction of the first pole piece 10.

Referring to fig. 3, an extending direction of the first tab 40 is parallel to a direction of the first cell unit 101 departing from the second cell unit 103. The extending direction of the second tab 50 is parallel to the direction of the second cell unit 103 away from the first cell unit 101, but is not limited thereto. For example, as shown in fig. 4, in another embodiment, the extending directions of the first and

second tabs

40 and 50 of the electrode assembly 100a are parallel to the third direction Z, respectively.

Referring to fig. 5, 6 and 7, the first electrode sheet 10 includes a first current collector 11 and a first active layer 13. The first current collector 11 includes a first surface 111 and a second surface 113 opposite in the third direction Z. The first active layers 13 are respectively disposed on the first surface 111 and the second surface 113. The second electrode sheet 20 includes a second current collector 21 and a second active layer 23. The second current collector 21 includes a third surface 211 and a fourth surface 213 opposite to each other in the third direction Z. The second active layers 23 are respectively disposed on the third surface 211 and the fourth surface 213. The polarities of the first active layer 13 and the second active layer 23 are opposite. For example, the first active layer 13 is an anode active layer, and the second active layer 23 is a cathode active layer.

Referring to fig. 8 and 9, the isolation film 30 includes a first isolation film 31, a second isolation film 33, and a third isolation film 35. The first isolation film 31, the first pole piece 10, the second isolation film 33, the second pole piece 20, and the third isolation film 35 are sequentially stacked. The first isolation films 31 and the second isolation films 33 are arranged in a staggered manner and are projected to contact or partially overlap with each other, so that the first pole piece 10 and the second pole piece 20 in the first cell unit 101 and the second cell unit 103 are isolated. The second surface 113 of the first pole piece 10 and the fourth surface 213 of the second pole piece 20 are disposed to face each other.

Referring to fig. 5, fig. 6 and fig. 7, a first empty foil region 1111 is disposed on the first surface 111. The first tab 40 is disposed on the first current collector 11 exposed from the first empty foil region 1111, as shown in fig. 6. A second empty foil area 2111 is formed on the third surface 211, and the second tab 50 is disposed on the second current collector 21 exposed from the second empty foil area 2111. A portion of the first tab 40 is welded to the first current collector 11, and a welding area 4001 of the first tab 40 is close to the first active layer 13. A portion of the second tab 50 is welded to the second current collector 21, and a welding area (not shown) of the second tab 50 is adjacent to the second active layer 23. It is understood that in other embodiments, the welding region of the first tab 40 or the second tab 50 may be in other positions, as long as the first tab 40 and the second tab 50 extend out of the battery cell 200.

Referring to fig. 6, the arrangement position of the first tab 40 on the first current collector 11 along the second direction Y is set according to the connection position between the anode and the cathode of the battery cell 200 and an external element. The distance L between the symmetry axis 401 of the first tab 40 parallel to the first direction X and the symmetry axis 1001 of the first pole piece 10 preferably satisfies: l is more than or equal to 0 and less than or equal to (W/2-z/2), z is the width of the first pole lug, and W is the width of the first pole piece 10. The first limit position 403 and the second limit position 405 of the symmetry axis 401 of the first tab 40 are spaced from the symmetry axis 1001 of the first pole piece 10 by W/2-z/2. Similarly, the distance L between the symmetry axis (not shown) of the second pole piece 50 parallel to the first direction X and the symmetry axis 1001 of the first pole piece 10 preferably satisfies: l is more than or equal to 0 and less than or equal to (W/2-z/2).

According to one embodiment of the application, the width z of the first tab is selectable in the range of 1-15 mm; the selectable range of the width W of the first pole piece is 20-200 mm. Preferably, the width z of the first tab ranges from 5mm to 6 mm; the width W of the first pole piece can be selected from 50-100 mm.

Further, when the distance L is equal to 0, the first tab 40 is located at a middle symmetrical position of the first cell unit 101 in the second direction Y, and the second tab 50 is located at a middle symmetrical position of the second cell unit 103 in the second direction Y, so as to further improve the charge and discharge speed and the rate performance of the battery cell 200.

Referring to fig. 5, 7 and 10, a plurality of third empty foil regions 1113 exposing the first current collector 11 are disposed on the first surface 111 at intervals. A plurality of fourth empty foil areas 2113 exposing the second current collector 21 are arranged on the third surface 211 at intervals. The third empty foil region 1113 and the fourth empty foil region 2113 are located at a junction area of the first cell unit 101 and the second cell unit 103, so that the size of the first cell unit 101 and the second cell unit 103 in the junction area along the first direction X is reduced. The third empty foil area 1113 and the fourth empty foil area 2113 are correspondingly disposed and located on two opposite sides of the first pole piece 10 and the second pole piece 20, so that energy exchange can be achieved between the first cell unit 101 and the second cell unit 103, and further energy exchange is achieved while the size of the cell 200 in the first direction X is reduced, thereby improving the energy density of the cell 200.

Referring to fig. 2, the battery cell 200 further includes an electrolyte (not shown). The electrolyte permeates into the first cell unit 101 and the second cell unit 103 along the second direction Y, and the electrolyte permeates from the winding surface of the battery cell 200, so that the permeation performance of the electrolyte is improved.

The electrode assembly 100 and the battery cell 200 are wound from both ends to the middle to form the first cell unit 101 and the second cell unit 103 by the first pole piece 10, the second pole piece 20, and the separator 30, which are stacked. And the first battery cell unit 101 and the second battery cell unit 103 share the first tab 40 and the second tab 50, so that the energy density, the rate capability and the charging and discharging speed are improved.

Although the present application has been described in detail with reference to preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the spirit and scope of the present application.

Claims

An electrode assembly, comprising:

a first pole piece;

a second pole piece having a polarity opposite to the polarity of the first pole piece; and

a separator disposed between the first and second pole pieces; it is characterized in that the preparation method is characterized in that,

the first pole piece, the second pole piece and the isolating film are stacked and then wound from two ends to the middle to form a first battery cell unit and a second battery cell unit;

the electrode assembly further includes:

the first tab is arranged on the first tab and extends out of the first battery cell unit; and

and the second tab is arranged on the second pole piece and extends out of the second battery cell unit.
The electrode assembly of claim 1, wherein: the distance L between the symmetry axis of the first electrode lug or the second electrode lug parallel to the first direction and the symmetry axis of the first electrode piece parallel to the first direction satisfies the following conditions: l is more than or equal to 0 and less than or equal to (W/2-z/2), z is the width of the first pole piece or the second pole piece, W is the width of the first pole piece or the second pole piece, and the first direction is the length direction of the first pole piece.
The electrode assembly of claim 1, wherein the first tab extends in a direction parallel to a direction of the first cell unit away from the second cell unit; the extending direction of the second tab is parallel to the direction of the second battery cell unit departing from the first battery cell unit.
The electrode assembly of claim 1,

the first pole piece includes:

a first current collector comprising opposing first and second faces;

a first active layer disposed on the first and second faces, respectively;

a first empty foil area is arranged on the first surface, and the first tab is arranged on the first current collector exposed out of the first empty foil area;

the second pole piece includes:

a second current collector comprising opposing third and fourth faces;

a second active layer disposed on the third surface and the fourth surface, respectively;

and a second empty foil area is arranged on the third surface, and the second pole lug is arranged on the second current collector exposed out of the second empty foil area.
The electrode assembly of claim 4, wherein: welding a part of the first tab to the first current collector, wherein the welding area is close to the first active layer; and the part of the second lug is welded on the second current collector, and the welding area is close to the second active layer.
The electrode assembly of claim 4, wherein: a plurality of third empty foil areas exposing the first current collector are arranged on the first surface at intervals; a plurality of fourth empty foil areas exposing the second current collector are arranged on the third surface at intervals; the third empty foil area and the fourth empty foil area are located in a connection area of the first battery cell unit and the second battery cell unit, and the third empty foil area and the fourth empty foil area are correspondingly arranged and located on two sides of the first pole piece and the second pole piece, which are opposite to each other.
The electrode assembly of claim 1, wherein: the isolation films comprise a first isolation film, a second isolation film and a third isolation film; the first isolating film, the first pole piece, the second isolating film, the second pole piece and the third isolating film are sequentially superposed; and the first isolating films and the second isolating films are arranged in a staggered mode, and projection contact or partial overlapping is carried out, so that the first pole piece and the second pole piece in the first battery cell unit and the second battery cell unit are isolated.
The electrode assembly of claim 1, wherein: the first lug is made of nickel, and the second lug is made of aluminum.
An electric core, includes air pocket and electrode subassembly, electrode subassembly set up in the air pocket, its characterized in that: the electrode assembly is as set forth in any one of claims 1-8, said first tab and said second tab extending outside of said airbag.
The cell of claim 9, wherein: the battery cell further comprises electrolyte, and the electrolyte permeates into the first battery cell unit and the second battery cell unit along a second direction, wherein the second direction is parallel to the width direction of the first pole piece.