WO2021195910A1

WO2021195910A1 - Electrode assembly and battery

Info

Publication number: WO2021195910A1
Application number: PCT/CN2020/082261
Authority: WO
Inventors: 幸定清; 张政
Original assignee: 宁德新能源科技有限公司
Priority date: 2020-03-31
Filing date: 2020-03-31
Publication date: 2021-10-07
Also published as: CN113795939A

Abstract

Disclosed are an electrode assembly and a battery, comprising: a first electrode plate; a second electrode plate, the polarity of the second electrode plate being opposite to the polarity of the first electrode plate; a separator film, provided between the first electrode plate and the second electrode plate; the first electrode plate, the second electrode plate, and the separator film being stacked and then warped from either end to the middle to form a first battery unit and a second battery unit; a first electrode tab, provided on the first electrode plate and extending to the outside of the first battery unit; and a second electrode tab, provided on the second electrode plate and extending to the outside of the second battery unit. The electrode assembly and the battery, with the first electrode plate, the second electrode plate, and the separator film being stacked and warped from either side to the middle to form the first battery unit and the second battery unit, and, with the first battery unit and the second battery unit sharing the first electrode tab and the second electrode tab, increase the energy density, rate performance, and charging-discharging speed.

Description

Electrode assembly and battery cell

Technical field

This application relates to the field of batteries, and in particular to an electrode assembly and a battery cell containing the electrode assembly.

Background technique

At present, foldable flexible devices are gradually becoming a research hotspot, but the traditional battery structure is limited by the cubic structure and cannot meet the application of flexible devices. At present, one or more bare cells are used in flexible devices, but multiple bare cells need to lead out multiple tabs, which is not conducive to the infiltration of electrolyte, which makes the polarization of the cells too large, thereby reducing the rate performance of the cells And charging and discharging speed.

Summary of the invention

In view of this, it is necessary to provide an electrode assembly and a battery that are used in flexible devices and have good rate performance.

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

First pole piece

A second pole piece, the polarity of the second pole piece is opposite to the polarity of the first pole piece; and

An isolation membrane, which is arranged between the first pole piece and the second pole piece;

After the first pole piece, the second pole piece and the isolation film are stacked, the two ends are wound to the middle to form a first cell unit and a second cell unit;

The electrode assembly further includes:

The first pole ear is arranged on the first pole piece and extends to the outside of the first battery cell unit; and

The second tab is arranged on the second tab and extends to the outside of the second cell unit.

According to some embodiments of the present application, the distance L between the symmetry axis of the first pole piece or the second pole piece parallel to the first direction and the symmetry axis of the first pole piece parallel to the first direction satisfies : 0≤L≤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, so The first direction is the length direction of the first pole piece.

According to some embodiments of the present application, the extension direction of the first tab is parallel to the direction of the first cell unit away from the second cell unit; the extension direction of the second tab is parallel to the The direction of the second cell unit away from the first cell unit.

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

The first current collector includes a first surface and a second surface opposite to each other;

The first active layer is respectively disposed on the first surface and the second surface;

A first empty foil area is arranged on the first surface, and the first tab is arranged on the first current collector exposed by the first empty foil area;

The second pole piece includes:

The second current collector includes a third surface and a fourth surface opposite to each other;

The second active layer is respectively disposed on the third surface and the fourth surface;

A second empty foil area is arranged on the third surface, and the second tab is arranged on the second current collector exposed by the second empty foil area.

According to some embodiments of the present application, a part of the first tab is welded to the first current collector, and a welding area is close to the first active layer; a part of the second tab is welded to the first 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 regions exposing the first current collector are spaced on the first surface; a plurality of third empty foil regions exposing the second current collector are spaced on the third surface. The fourth empty foil zone; the third empty foil zone and the fourth empty foil zone are located at the junction area of the first cell unit and the second cell unit, the third empty foil zone and The fourth empty foil area is correspondingly arranged and located on opposite sides of the first pole piece and the second pole piece.

According to some embodiments of the present application, the isolation film includes a first isolation film, a second isolation film, and a third isolation film; the first isolation film, the first pole piece, the second isolation film, and the The second pole piece and the third isolation film are sequentially stacked; and the first isolation film and the second isolation film are alternately arranged, projected contact or partially overlapped, so that the first cell unit and the The first pole piece and the second pole piece are isolated in the second cell unit.

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

The present application also provides a battery cell, including an air bag and the above-mentioned electrode assembly, the electrode assembly is arranged in the air bag, and the first tab and the second tab extend out of the air bag .

According to some embodiments of the present application, the battery cell further includes an electrolyte, which penetrates into the first battery cell unit and the second battery cell unit along a second direction, and the second direction is parallel to The width direction of the first pole piece.

The electrode assembly and the cell are wound from both ends to the middle through the stacked first pole piece, the second pole piece, and the isolation film to form a first cell unit and a second cell unit, and The first cell unit and the second cell unit share the first tab and the second tab, which improves energy density, rate performance, and charge and discharge speed.

Description of the 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 diagram of the structure of the battery cell shown in Fig. 1 when the air bag is opened.

3 is a schematic diagram of the structure of the first cell unit and the second cell unit shown in FIG. 1 by winding and forming the cell.

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

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 diagram of the structure of the first pole piece shown in FIG. 1 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 diagram of the structure of the battery cell shown in FIG. 1 when the first pole piece, the second pole piece and the isolation film are stacked.

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

10 is a schematic diagram of the structure of the area where the first cell unit and the second cell unit are connected in the cell shown in FIG. 2.

Symbol description of main components

Cell 200

Air bag 201

Electrode assembly 100, 100a

The first pole piece 10

Symmetry axis 1001

The first episode of fluid 11

The first side 111

The first empty foil area 1111

The third empty foil area 1113

The second side 113

The first active layer 13

The second pole piece 20

The second episode of fluid 21

The third aspect 211

The second empty foil area 2111

The fourth empty foil area 2113

The fourth side 213

The second active layer 23

Isolation film 30

The first isolation film 31

Second isolation film 33

The third isolation film 35

First pole ear 40

Symmetry axis 401

The first extreme position 403

The second extreme position 405

Welding area 4001

The second pole ear 50

The first battery cell unit 101

Second battery cell unit 103

The first direction X

The second direction Y

The third direction Z

The following specific embodiments will further illustrate this application in conjunction with the above-mentioned drawings.

Detailed ways

The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of this application.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field of this application. The terms used in the specification of the application herein are only for the purpose of describing specific embodiments, and are not intended to limit the application.

Some embodiments of the present application propose an electrode assembly, including:

First pole piece

The above-mentioned electrode assembly is wound from both ends to the middle through the stacked first pole piece, the second pole piece, and the isolation film to form a first cell unit and a second cell unit, and the first cell The unit and the second battery cell unit share the first tab and the second tab, which improves energy density, rate performance, and charging and discharging speed.

Hereinafter, some embodiments of the present application will be described in detail with reference to the accompanying drawings. In the case of no conflict, the following embodiments and features in the embodiments can be combined with each other.

Please refer to FIG. 1, FIG. 2 and FIG. 3 at the same time. An embodiment of the present application provides a battery core 200. The battery cell 200 includes an air bag 201 and an electrode assembly 100. The electrode assembly 100 is arranged in the air bag 201. The electrode assembly 100 includes a first pole piece 10, a second pole piece 20, an isolation membrane 30, a first pole piece 40 and a second pole piece 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 material of the first tab 40 is nickel, and the material of the second tab 50 is aluminum.

The isolation film 30 is arranged 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 isolation film 30 are stacked, they are wound from both ends to the middle to form a first cell unit 101 and a second cell unit 103. As shown in Figure 1, both ends are wound clockwise, but not limited to this. For example, in other embodiments, the two ends can also be wound counterclockwise at the same time. The first tab 40 is disposed on the first pole piece 10 and extends to the outside of the first cell unit 101. The second tab 50 is disposed on the second pole piece 20 and extends out of the second cell unit 103. The first tab 40 and the second tab 50 protrude outside the air bag 201.

The above-mentioned electrode assembly 100 and the cell 200 are formed by winding and forming two of the first cell unit 101 and the second cell unit 103 to form a unit of a bare cell, and the electrode assembly 100 is provided with only one of the first tab 40 and One of the second tab 50 and the two units constituting the bare cell share one first tab 40 and one second tab 50, which improves the rate performance and charging and discharging speed.

Please refer to FIGS. 5 and 6, for clarity of the subsequent description, it is defined that the first direction X is the length direction of the first pole piece 10, the second direction Y is the width direction of the first pole piece 10, and the third direction Z It is the thickness direction of the first pole piece 10.

Please refer to FIG. 3, the extending direction of the first tab 40 is parallel to the direction in which the first cell unit 101 faces away from the second cell unit 103. The extension 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 to this. For example, as shown in FIG. 4, in another embodiment, the extending directions of the first tab 40 and the second tab 50 of the electrode assembly 100a are respectively parallel to the third direction Z.

Referring to FIGS. 5, 6 and 7 at the same time, the first pole piece 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 to each other in the third direction Z. The first active layer 13 is respectively disposed on the first surface 111 and the second surface 113. The second pole piece 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 in the third direction Z. The second active layer 23 is 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 FIGS. 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 alternately arranged and projected in contact or partially overlapped, so that the first pole piece 10 in the first cell unit 101 and the second cell unit 103 It is isolated from the second pole piece 20. The second surface 113 of the first pole piece 10 and the fourth surface 213 of the second pole piece 20 are arranged opposite to each other.

Please refer to FIG. 5, FIG. 6 and FIG. 7 at the same time, a first empty foil area 1111 is provided on the first surface 111. The first tab 40 is disposed on the first current collector 11 exposed by the first empty foil region 1111, as shown in FIG. 6. A second empty foil area 2111 is provided on the third surface 211, and the second tab 50 is provided on the second current collector 21 exposed by the second empty foil area 2111. Part of the first tab 40 is welded to the first current collector 11, and the welding area 4001 of the first tab 40 is close to the first active layer 13. Part of the second tab 50 is welded to the second current collector 21, and the welding area (not shown) of the second tab 50 is close to the second active layer 23. It can be understood that in other embodiments, the welding area of the first tab 40 or the second tab 50 can also be in other positions, as long as the first tab 40 and the second tab 50 can be easily extended. It suffices to exit the outer side of the battery core 200.

Please refer to FIG. 6, the position of the first tab 40 on the first current collector 11 along the second direction Y needs to be set according to the connection positions of the anode and cathode of the battery cell 200 and external components. Certainly. The distance L between the symmetry axis 401 of the first pole tab 40 parallel to the first direction X and the symmetry axis 1001 of the first pole piece 10 preferably satisfies: 0≤L≤(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 distance between the first extreme position 403 and the second extreme position 405 of the symmetry axis 401 of the first pole piece 40 and the symmetry axis 1001 of the first pole piece 10 is 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: 0≤L≤(W/ 2-z/2).

According to an embodiment of the present application, the optional range of the width z of the first pole lug is 1-15 mm; the optional range of the width W of the first pole piece is 20-200 mm. Preferably, the range of the width z of the first pole lug is 5-6 mm; the optional range of the width W of the first pole piece is 50-100 mm.

Further, when the distance L=0, the first tab 40 is located symmetrically in the middle of the first cell unit 101 in the second direction Y, and the second tab 50 is located at the The second cell unit 103 is symmetrical in the middle of the second direction Y, which further improves the charging and discharging speed and rate performance of the cell 200.

Referring to FIG. 5, FIG. 7 and FIG. 10, a plurality of third empty foil regions 1113 exposing the first current collector 11 are provided on the first surface 111 at intervals. A plurality of fourth empty foil regions 2113 exposing the second current collector 21 are provided on the third surface 211 at intervals. The third empty foil area 1113 and the fourth empty foil area 2113 are located in the contact area of the first cell unit 101 and the second cell unit 103, so that the first cell unit 101 and The size of the second cell unit 103 in the contact area along the first direction X decreases. The third empty foil area 1113 and the fourth empty foil area 2113 are correspondingly arranged and located on opposite sides of the first pole piece 10 and the second pole piece 20, so that the first battery cell The unit 101 and the second cell unit 103 can realize energy exchange, so that the cell 200 can realize energy exchange while the size of the cell 200 is reduced in the first direction X, thereby increasing the energy density of the cell 200.

Please refer to FIG. 2, the battery cell 200 further includes an electrolyte (not shown). The electrolyte penetrates into the first cell unit 101 and the second cell unit 103 along the second direction Y, and the electrolyte penetrates from the winding surface of the cell 200 to improve the electrolysis. Liquid permeability.

The electrode assembly 100 and the cell 200 are wound from both ends to the middle through the stacked first pole piece 10, the second pole piece 20, and the isolation film 30 to form a first cell unit 101 and a second cell. Two battery cell unit 103. In addition, the first cell unit 101 and the second cell unit 103 share the first tab 40 and the second tab 50, which improves energy density, rate performance, and charge and discharge speed.

The above embodiments are only used to illustrate the technical solutions of the application and not to limit them. Although the application has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the application can be modified or equivalently replaced , Without departing from the spirit and essence of the technical solution of this application.

Claims

An electrode assembly, including:

First pole piece

A second pole piece, the polarity of the second pole piece is opposite to the polarity of the first pole piece; and

The isolation membrane is arranged between the first pole piece and the second pole piece; characterized in that,

After the first pole piece, the second pole piece and the isolation film are stacked, the two ends are wound to the middle to form a first cell unit and a second cell unit;

The electrode assembly further includes:

The first pole ear is arranged on the first pole piece and extends to the outside of the first battery cell unit; and

The second tab is arranged on the second tab and extends to the outside of the second cell unit.
The electrode assembly of claim 1, wherein the symmetry axis of the first or second tab parallel to the first direction and the first pole piece parallel to the first direction The distance L between the axis of symmetry satisfies: 0≤L≤(W/2-z/2), z is the width of the first pole or the second pole, and W is the first pole piece or the The width of 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 extension direction of the first tab is parallel to the direction of the first cell unit away from the second cell unit; The extending direction is parallel to the direction of the second cell unit away from the first cell unit.
The electrode assembly of claim 1, wherein:

The first pole piece includes:

The first current collector includes a first surface and a second surface opposite to each other;

The first active layer is respectively disposed on the first surface and the second surface;

A first empty foil area is arranged on the first surface, and the first tab is arranged on the first current collector exposed by the first empty foil area;

The second pole piece includes:

The second current collector includes a third surface and a fourth surface opposite to each other;

The second active layer is respectively disposed on the third surface and the fourth surface;

A second empty foil area is arranged on the third surface, and the second tab is arranged on the second current collector exposed by the second empty foil area.
The electrode assembly of claim 4, wherein: part of the first tab is welded to the first current collector, and the welding area is close to the first active layer; Partly welded on the second current collector, and the welded area is close to the second active layer.
The electrode assembly of claim 4, wherein: the first surface is provided with a plurality of third empty foil regions exposing the first current collector at intervals; the third surface is provided with a plurality of exposed areas at intervals The fourth empty foil area of the second current collector; the third empty foil area and the fourth empty foil area are located in the contact area of the first cell unit and the second cell unit, the The third empty foil area and the fourth empty foil area are correspondingly arranged and located on opposite sides of the first pole piece and the second pole piece.
8. The electrode assembly of claim 1, wherein the isolation film comprises a first isolation film, a second isolation film, and a third isolation film; the first isolation film, the first pole piece, and the The second isolation film, the second pole piece, and the third isolation film are stacked in sequence; and the first isolation film and the second isolation film are arranged in a staggered manner, projecting contact or partially overlapping, so that the first isolation film The first pole piece and the second pole piece in the cell unit and the second cell unit are isolated.
The electrode assembly of claim 1, wherein the material of the first tab is nickel, and the material of the second tab is aluminum.
A battery cell, comprising an air bag and an electrode assembly, the electrode assembly is arranged in the air bag, characterized in that: the electrode assembly is the electrode assembly according to any one of claims 1-8, and the first One pole and the second pole protrude out of the air bag.
The battery cell according to claim 9, wherein the battery cell further comprises an electrolyte, and the electrolyte penetrates into the first battery cell unit and the second battery cell unit in a second direction, so The second direction is parallel to the width direction of the first pole piece.