WO2024067403A1

WO2024067403A1 - Electrode plate and battery

Info

Publication number: WO2024067403A1
Application number: PCT/CN2023/120761
Authority: WO
Inventors: 张蓝天; 胡大林; 廖兴群
Original assignee: 惠州市豪鹏科技有限公司
Priority date: 2022-09-29
Filing date: 2023-09-22
Publication date: 2024-04-04
Also published as: CN218827228U

Abstract

An electrode plate and a battery comprising the electrode plate. The electrode plate comprises: a current collector (1), the current collector (1) being provided with a first side surface and a second side surface arranged opposite each other; an active layer (3), the active layer (3) being coated on both side surfaces of the current collector (1), the active layer (3) being cleared away from a pre-determined area of the first side surface of the current collector (1) so as to form a first empty foil zone (11), and the first empty foil zone (11) being provided with a first opening facing upwards and a second opening perpendicular to the first side surface of the current collector (1); and a tab, one end of the tab extending into the first empty foil zone (11) and being welded to the first side surface of the current collector (1), the other end of the tab extending out of the first empty foil zone (11), the active layer (3) extending towards both sides of the opening of the first empty foil zone (11) so as to respectively form projections (5), and the tab extending out of the current collector (1) from opposite sides of the two projections (5).

Description

Electrode and battery

This application claims priority to the Chinese patent application filed on September 29 , 2022 , with application number 202222619243.6 and invention name “Pole and Battery”, all contents of which are incorporated by reference into this application.

Technical Field

The present application belongs to the field of battery technology, and in particular relates to a pole piece and a battery.

Background technique

The existing tab welding technology is divided into external tab welding and internal tab welding.

For the external tabs, after the foil is evenly coated with active material, empty foil areas are set at the head and tail of the foil to place the tabs, and then welding is performed. In order to avoid burrs on the tabs, more empty foil areas will remain in the empty foil areas of the pole pieces, which causes a waste of resources and a loss of energy density of the battery cell.

Compared with the external pole tab welding technology, the embedded pole tab is to evenly coat the foil with active material, then the pole piece is laser washed to expose the empty foil area, and the pole tab is placed on the blank foil for welding. This process can improve the energy density of the battery cell, but unreasonable welding position will cause the pole tab to tilt or even fall off.

The embedded tab welding technology in the related art has the problem of unreasonable welding position, resulting in waste of welding resources, tab falling off, etc.

In addition, how to increase the area of the active layer and enhance the energy density of the electrode is also an issue that needs to be considered in electrode design.

Summary of the invention

The technical problem to be solved by the present application is to provide a pole piece and a battery to increase the area of the active layer and enhance the energy density of the pole piece.

In order to solve the above technical problems, on the one hand, an embodiment of the present application provides a pole piece, including:

The current collector has a first side surface and a second side surface that are arranged opposite to each other;

An active layer, the active layer being coated on both side surfaces of the current collector;

The active layer is removed from a predetermined area of the first side surface of the current collector to form a first empty foil area, wherein the first empty foil area The foil area has a first opening facing upward and a second opening perpendicular to the first side surface of the current collector;

A pole ear, one end of which extends into the first empty foil area and is welded to the first side surface of the current collector, and the other end of which extends out of the first empty foil area; the distance between the bottom surface of the pole ear and the bottom wall of the first empty foil area is 2-6 mm, and the distance between the right side surface of the pole ear and the right side wall of the first empty foil area is 0.1 to 0.2 times the width of the first empty foil area;

The active layer extends toward both sides of the opening of the first empty foil area to form protrusions respectively, and the electrode tab extends out of the current collector from opposite sides of the two protrusions.

Optionally, an upper surface of the protrusion is flush with an upper surface of the current collector.

Optionally, the distance between the bottom surface of the electrode tab and the bottom wall of the first empty foil area is 2-6 mm;

The distance between the left side surface of the electrode ear and the left side wall of the first empty foil area is 0.1 to 0.2 times the width of the first empty foil area;

The distance between the right side surface of the electrode tab and the right side wall of the first empty foil area is 0.1 to 0.2 times the width of the first empty foil area.

Optionally, the first empty foil area is rectangular, and two corners of the bottom of the first empty foil area are both arc-shaped transitions; the diameter of the arc-shaped transition is greater than the width of the first empty foil area.

Optionally, the length of the first empty foil area is 15-30 mm, and the width of the first empty foil area is 8-12 mm.

Optionally, the areas on the facing sides of the two protrusions are provided with grooves, the cross-sectional shape of the grooves is rectangular, the grooves are formed by cutting out the current collector and the active layer within their cross-sectional shape, the length of the grooves parallel to the current collectors is 0.8-1.3 times the length of the first empty foil area; the width of the grooves is 0.1-0.3 times the width of the first empty foil area.

Optionally, a weld mark is provided on the surface of the electrode tab away from the current collector, and the distance between the bottom edge of the weld mark and the bottom wall of the first empty foil area is 2.5-3 mm; the distance between the upper edge of the weld mark and the upper surface of the groove is 3-8 mm; the distance between the bottom edge of the weld mark and the bottom surface of the protrusion is 1.5-2 mm.

Optionally, an adhesive layer is attached to the weld print.

Optionally, a groove is provided in the area on the opposite sides of the two protrusions, the cross-sectional shape of the groove is a regular geometric shape, the groove is formed by cutting out the current collector and the active layer within its cross-sectional shape, and the length of the groove parallel to the current collector is 0.8-1.3 times the width of the first empty foil area; the width of the groove is 0.1-0.3 times the width of the first empty foil area.

Optionally, the active layer is removed from a predetermined area of the second side surface of the current collector to form a second empty foil area. The second empty foil area has a third opening facing upward and a fourth opening perpendicular to the first side surface of the current collector.

Optionally, the orthographic projections of the second empty foil area and the first empty foil area on the surface of the current collector coincide with each other.

According to the pole piece of the embodiment of the present application, the active layer extends toward both sides of the opening of the first empty foil area to form protrusions respectively, and the pole ears extend out of the current collector from the opposite sides of the two protrusions. In this way, the area of the active layer 2 can be increased and the energy density of the pole piece can be enhanced.

In addition, during welding, the distance between the pole piece and the empty foil area is controlled so that the welding position of the pole piece and the empty foil area is a better welding position to improve the welding effect and prevent the pole ear from loosening easily.

In addition, the present application further improves the welding effect by limiting the relative position of the welding mark on the pole ear in the empty foil area. The protrusion in this embodiment reduces the area of the first empty foil area and increases the area of the active layer on the pole piece, thereby achieving the effect of increasing the battery density.

On the other hand, an embodiment of the present application further provides a battery, comprising the above-mentioned electrode.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the specification and, together with the description, serve to explain the principles of the specification.

FIG1 is an overall schematic diagram of a pole piece provided in a first embodiment of the present application;

FIG2 is a half-section schematic diagram of a pole piece provided in the first embodiment of the present application;

3 is a schematic diagram of the coordination of the current collector and the active layer of the pole piece provided in the first embodiment of the present application;

FIG4 is a schematic diagram of a weld mark structure on a pole ear of a pole piece provided in the first embodiment of the present application;

FIG5 is a schematic diagram of a half-section structure of a pole piece provided in the third embodiment of the present application.

The reference numerals in the specification are as follows:

1. Current collector; 11. First empty foil area; 111. Arc transition; 12. Second empty foil area; 2. Active layer; 3. Ear; 4. Weld mark; 5. Protrusion; 6. Groove.

Detailed ways

In order to make the technical problems, technical solutions and beneficial effects solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

First embodiment

As shown in FIG. 1 and FIG. 2 , a pole piece provided in the first embodiment of the present application includes a current collector 1, an active layer 2 and a pole ear 3. The current collector has a first side surface and a second side surface arranged oppositely, and the active layer 2 is coated on the two side surfaces of the current collector 1 respectively, and the active layer 2 is composed of an active material. The active layer 2 in the predetermined area is removed on the first side surface of the current collector 1 to form a first empty foil area 11, that is, the active layer 2 on the surface of the current collector 1 is cleaned by laser, so that the current collector 1 in the predetermined area is exposed, and the predetermined area is the first empty foil area 11. Naturally, the first empty foil area 11 has an opening facing the vertical current collector 1. When cleaning, it is first washed from one side wall in the width direction of the current collector 1 to the other side wall, so that the first empty foil area 11 also has a side wall facing the width direction of the current collector 1. The direction toward the side wall is defined as facing upward. At this time, the first empty foil area 11 has an opening facing upward. In order to increase the area of the active layer 2 and enhance the energy density of the pole piece, the active layer 2 extends toward both sides of the opening of the first empty foil area 11 to form protrusions 5 respectively. The protrusions in this embodiment reduce the area of the first empty foil area and increase the area of the active layer on the pole piece, thereby achieving the effect of increasing the battery density.

Moreover, the upper edge of the protrusion 5 is flush with the upper surface of the current collector 1 , and the protrusion 5 fits the edge of the current collector as closely as possible, so that the area of the active layer is increased to the maximum extent on the basis of the active layer being stably fixed on the current collector.

The first empty foil area 11 and the second empty foil area 12 are respectively arranged at the relative positions of the two side surfaces of the current collector 1, and the second empty foil area 12 and the first empty foil area 11 are arranged in pairs, and the second empty foil area 12 has a third opening and a fourth opening, the third opening faces upward, and the fourth opening faces the opposite direction of the second opening. In other words, the projections of the first empty foil area 11 and the second empty foil area 12 on the surface of the current collector 1 on both sides of the current collector 1 completely overlap. The pole ear 3 is welded on the current collector 1 in the first empty foil area 11. The distance between the bottom edge of the pole ear 3 and the bottom wall of the first empty foil area 11 is defined as A, and the value of A is 2-6mm, and the side wall of one side of the pole ear 3 is defined as the right side, and the distance between the right side edge of the pole ear 3 and the side wall of the first empty foil area 11 is 0.1 to 0.2 times the width of the first empty foil area 11. The distance between the left side of the pole ear and the left side wall of the first empty foil area is 0.1 to 0.2 times the width of the first empty foil area 11.

In the present embodiment, the first empty foil area 11 is rectangular, more specifically, the length of the first empty foil area 11 is 15-30 mm, the width of the first empty foil area 11 is 8-12 mm, one end of the length direction of the first empty foil area 11 is the upper opening of the first empty foil area 11, the other end of the length direction of the first empty foil area 11 is the bottom wall of the first empty foil area 11, and the cross-sectional shapes of the two corners of the bottom of the first empty foil area 11 are both arc-shaped transitions 111. The diameter of the arc-shaped transition 111 is greater than the width of the first empty foil area 11. In the prior art, right-angled corners tend to increase waste and are also prone to wrinkling, while the corners of the arc-shaped transition 111 increase the area of the active layer 2 and reduce waste on the one hand, and on the other hand, the arc-shaped transition 111 is smoother and less prone to wrinkling.

3 and 4, in this embodiment, a welding mark 4 is provided on the surface of the electrode tab 3 away from the current collector 1, and the distance between the bottom edge of the welding mark 4 and the bottom wall of the first empty foil area 11 is defined as B, and the value of B is 2.5-3 mm; the distance between the upper edge of the welding mark 4 and the upper surface of the groove 5 is defined as D, and the value of D is 3-8 mm. The distance between the bottom edge of the welding mark 4 and the bottom surface of the protrusion 5 is defined as C, and the value of C is 1.5-2 mm. After welding is completed, a glue layer is attached to the surface of the welding mark 4.

In this embodiment, a portion of the current collector 1 is cut off along its thickness direction to form a groove 6. The groove 6 is mainly used to avoid the occurrence of a short circuit caused by the contact between the tab 3 and the active material of the active layer 2. The groove 6 is located on the upper opening side of the first empty foil area 11 so that one side edge of the groove 6 is flush with the edge of the width side of the current collector 1; the groove 6 in this embodiment is rectangular, the length direction of the groove 6 is parallel to the length direction of the current collector 1, and the length of the groove 6 is 0.8-1.3 times the length of the first empty foil area 11; the width of the groove 6 is 0.1-0.3 times the width of the first empty foil area 11.

Second embodiment

The pole piece of the second embodiment of the present application is different from the first embodiment in that the areas on the opposite sides of the two protrusions are provided with grooves, the cross-sectional shape of the grooves is a regular geometric shape, the grooves are formed by cutting out the current collector and the active layer within the cross-sectional shape, and the length of the grooves parallel to the current collector is 0.8-1.3 times the width of the first empty foil area 11; the width of the grooves is 0.1-0.3 times the width of the first empty foil area. In the present application, the grooves can be square, trapezoidal, etc. to reduce the contact between the active layer on the surface of the pole ear and the current collector.

Third embodiment

The pole piece of the third embodiment of the present application is different from the pole piece of the first embodiment in that, as shown in FIG. 5 , The pole piece in the example only has the first empty foil area 11 , and the second side surface of the current collector 1 is not provided with the second empty foil area 12 .

Fourth embodiment

A fourth embodiment of the present application provides a battery, which includes the pole piece described in any of the above embodiments.

The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

A pole piece, characterized by comprising:

A current collector (1); the current collector (1) has a first side surface and a second side surface which are arranged opposite to each other;

An active layer (3), the active layer (3) being coated on both side surfaces of the current collector (1);

The active layer (3) is removed from a predetermined area of the first side surface of the current collector (1) to form a first empty foil area (11), wherein the first empty foil area (11) has a first opening facing upward and a second opening perpendicular to the first side surface of the current collector (1);

A pole lug, one end of which extends into the first empty foil area (11) and is welded to the first side surface of the current collector (1), and the other end of which extends out of the first empty foil area (11);

The active layer (3) extends toward both sides of the opening of the first empty foil area (11) to form protrusions (5) respectively, and the electrode tab extends out of the current collector (1) from the opposite sides of the two protrusions (5).
The pole piece according to claim 1, characterized in that the upper surface of the protrusion (5) is flush with the upper surface of the current collector (1).
The pole piece according to claim 1, characterized in that the distance between the bottom surface of the pole ear and the bottom wall of the first empty foil area (11) is 2-6 mm;

The distance between the left side surface of the electrode tab and the left side wall of the first empty foil area (11) is 0.1 to 0.2 times the width of the first empty foil area (11);

The distance between the right side surface of the electrode tab and the right side wall of the first empty foil area (11) is 0.1 to 0.2 times the width of the first empty foil area (11).
The pole piece according to claim 1 is characterized in that the first empty foil area (11) is rectangular, and the two corners at the bottom of the first empty foil area (11) are both arc-shaped transitions (111); the diameter of the arc-shaped transition (111) is greater than the width of the first empty foil area (11).
The pole piece according to claim 2 is characterized in that the length of the first empty foil area (11) is 15-30 mm, and the width of the first empty foil area (11) is 8-12 mm.
The pole piece according to claim 1, characterized in that a groove (6) is provided in the area on the opposite sides of the two protrusions (5), the cross-sectional shape of the groove (6) is rectangular, the groove (6) is formed by cutting out the current collector (1) and the active layer (3) within its cross-sectional shape, and the length of the groove (6) parallel to the current collector (1) is 0.8-1.3 times the length of the first empty foil area (11); the width of the groove (6) is 0.8-1.3 times the length of the first empty foil area (11); 0.1-0.3 times the width.
The pole piece according to claim 6 is characterized in that a welding mark (4) is provided on the surface of the pole ear away from the current collector (1), and the distance between the bottom edge of the welding mark (4) and the bottom wall of the first empty foil area (11) is 2.5-3 mm; the distance between the upper edge of the welding mark (4) and the upper surface of the groove (6) is 3-8 mm; the distance between the bottom edge of the welding mark (4) and the bottom surface of the protrusion (5) is 1.5-2 mm.
The pole piece according to claim 7, characterized in that a glue layer is attached to the weld mark (4).
The pole piece according to claim 1 is characterized in that a groove (6) is provided in the area on the opposite sides of the two protrusions (5), the cross-sectional shape of the groove (6) is a regular geometric shape, the groove (6) is formed by cutting out the current collector (1) and the active layer (3) within its cross-sectional shape, and the length of the groove (6) parallel to the current collector (1) is 0.8-1.3 times the width of the first empty foil area (11); the width of the groove (6) is 0.1-0.3 times the width of the first empty foil area (11).
The pole piece according to claim 1 is characterized in that the active layer (3) is removed from a predetermined area of the second side surface of the current collector (1) to form a second empty foil area (12), and the second empty foil area (12) has a third opening facing upward and a fourth opening perpendicular to the first side surface of the current collector (1).
The pole piece according to claim 10, characterized in that the orthographic projections of the second empty foil area (12) and the first empty foil area (11) on the surface of the current collector (1) coincide with each other.
A battery, characterized by comprising the pole piece according to any one of claims 1 to 11.