CN113812016A

CN113812016A - Pole piece, electrode assembly applying pole piece, battery and electric device

Info

Publication number: CN113812016A
Application number: CN202080034553.2A
Authority: CN
Inventors: 连旭宸; 王佳伟; 李�瑞; 江行国
Original assignee: Ningde Amperex Technology Ltd
Current assignee: Ningde Amperex Technology Ltd
Priority date: 2020-03-30
Filing date: 2020-03-30
Publication date: 2021-12-17
Anticipated expiration: 2040-03-30
Also published as: WO2021195851A1; CN113812016B

Abstract

The application provides a pole piece, which comprises a first area; a second region connecting the first region; the first active layer is arranged in the first area, extends to the second area to form a second active layer, and the proportion of the thickness of the second active layer to the thickness of the first active layer ranges from 80% to 100%. The electrode assembly, the battery and the electric device are further provided, and the condition that the edge of the electrode plate is thin can be improved by using the electrode plate, so that the safety of the electrode plate is improved.

Description

Pole piece, electrode assembly applying pole piece, battery and electric device

Technical Field

The application relates to the technical field of batteries, in particular to a pole piece, an electrode assembly applying the pole piece, a battery and an electric device.

Background

In the process of producing the battery, coating on the pole piece is an essential process. And the active material flows on the current collector in the process of coating the pole piece, and the situation of leveling of the active material at the edge of the current collector can occur after the active material flows on the current collector inevitably, namely, the thicknesses of the active material on the current collector are different. Therefore, a thinning area exists at the edge of the pole piece, the thinning area is located at the head of the battery core, and the area is thin, namely, the active substances are less, so that when the pole piece is manufactured into a battery, the phenomenon that the active substances of the battery are unbalanced occurs, and further the safety problem is caused.

Disclosure of Invention

In view of the above, it is necessary to provide a pole piece, an electrode assembly, a battery and an electric device using the pole piece, which aim to ensure the balance of active materials in the battery.

A pole piece, comprising:

a first region;

a second region connecting the first region; and

the first active layer is arranged in the first area, extends to the second area to form a second active layer, and the proportion of the thickness of the second active layer to the thickness of the first active layer ranges from 80% to 100%.

In at least one embodiment, the pole piece further comprises a first pole tab, the first pole tab is connected with the second area, and part of the second active layer is coated on the first pole tab.

In at least one embodiment, the second active layer is coated in a distance ranging from 0.4mm to 1.4mm in the length direction of the first tab.

In at least one embodiment, the second active layer accounts for 3.6 to 20% of the first tab in the length direction of the first tab.

In at least one embodiment, the surface of the pole piece is further provided with an insulating layer, and the insulating layer is arranged at the edge of the second region far away from the first region, so that the second active layer extending to the edge of the second region extends towards the first region.

In at least one embodiment, the material of the insulating layer comprises a ceramic.

In at least one embodiment, the width of the second region ranges from 4mm to 10 mm.

In at least one embodiment, the width of the second region is 8 mm.

An electrode assembly comprises a plurality of first pole pieces and second pole pieces, wherein the first pole pieces are the pole pieces, the first pole pieces and the second pole pieces are arranged at intervals, and the first pole pieces and the second pole pieces are stacked or wound into the electrode assembly.

A battery includes a case and the electrode assembly described above, the electrode assembly being housed within the case.

An electric device comprises a body and the battery, wherein the battery is arranged in the body.

The pole piece provided by the application solves the problem of a thinning area on the pole piece by keeping the proportion range of the thicknesses of the active layers on the first area and the second area between 80% and 100%. Keep the thickness of active layer on first region and the second region roughly the same for the quantity of the active material in first region and second region on the pole piece keeps roughly the same, has promoted the security of pole piece in the use.

Drawings

Fig. 1 is a schematic plan view of the arrangement of the pole pieces in the first embodiment.

FIG. 2 is a schematic plan view of the first embodiment of the present invention after cutting the pole piece.

Fig. 3 is a schematic cross-sectional view of the pole piece shown in fig. 2 along the thickness direction.

Fig. 4 is a schematic plan view of the tab after being cut in the first embodiment.

FIG. 5 is a schematic plan view of another embodiment of the pole piece.

Fig. 6 is a schematic plan view of the arrangement of the pole pieces in the second embodiment.

Fig. 7 is a schematic plan view of the arrangement of the pole pieces in the third embodiment.

Fig. 8 is a schematic plan view of a pole piece including a tab in a third embodiment.

Fig. 9 is a perspective view schematically illustrating an electrode assembly of a fourth embodiment.

Fig. 10 is a schematic plan view of a battery of the fifth embodiment.

Fig. 11 is a perspective view of an electric device according to a sixth embodiment.

Description of the main elements

Pole piece 100

First current collector 10

First region 11

First active layer 111

Second region 12

Second active layer 121

First tab region 13

First tab 131

Insulating layer 14

Electrode assembly 200

Second pole piece 20

Second lug 21

Isolation diaphragm 22

Battery 300

Housing 30

Power utilization device 400

Body 40

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.

It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. When an element is referred to as being "on" another element, it can be directly on the other element or intervening elements may also be present. The terms "top," "bottom," "upper," "lower," "left," "right," "front," "rear," and the like as used herein are for illustrative purposes only.

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.

The application provides a pole piece, including first region, second region, first active layer, the second region is connected first region, first active layer set up in first region, first active layer extends to the second region forms the second active layer, the thickness of second active layer with the thickness proportion scope of first active layer is 80% to 100%.

By using the pole piece, the problem caused by the thinning area at the edge of the pole piece is effectively solved, and the difference in the proportion of active substances between the pole pieces is reduced, so that the balance of the active substances in the battery is kept when the pole piece is manufactured into the battery, and the safety of the battery is improved.

In the following, some embodiments of the present application will be described in detail, and features in the following embodiments, that is, embodiments, may be combined with each other without conflict.

Comparative examples

Referring to fig. 1, 2 and 3, a pole piece 100 includes a first current collector 10, a first region 11 and a second region 12, where the first region 11 and the second region 12 are two regions divided on the first current collector 10, and the second region 12 connects the first region 11. The pole piece 100 further includes a first active layer 111, the first active layer 111 is disposed on the first region 11, and the first active layer 111 extends to the second region 12 to form a second active layer 121, and a thickness of the second active layer 121 is smaller than a thickness of the first active layer 111. I.e., the second region 12 on the first current collector 10 forms a thinned region.

Specifically, the first region 11 and the second region 12 together form an upper surface of the first current collector 10, and the first region 11 occupies a larger area on the first current collector 10. And the second region 12 is a region where the first current collector 10 is substantially located at the edge, and occupies a smaller area of the first current collector 10. The pole piece 100 is formed by coating an active layer on the first current collector 10, the first active layer 111 starts to be coated on the first region 11, the first active layer 111 flows on the first region 11, and the thickness of the first active layer 111 on the first region 11 is substantially uniform. The first active layer 111 flows toward the second region 12 to form the second active layer 121, the thickness of the second active layer 121 is smaller than that of the first active layer 111, and the thickness of the second active layer 121 is thinner as it is closer to the edge of the second region 12.

As described above, in the case that the thinning region is formed on the first current collector 10 in the process of manufacturing the electrode sheet 100, when the electrode sheet 100 is used, the active layer at the edge of the second region 12 is too thin, so that the ratio of active materials on the anode sheet and the cathode sheet is less than 1 in the battery manufactured by using the electrode sheet 100 as the anode sheet, and the lithium deposition phenomenon occurs in the battery, thereby causing a safety problem.

First embodiment

In order to solve the problem that a thinning area is formed at the edge position of the pole piece 100, the present application provides a pole piece 100, in the same manner as in the comparative example, the pole piece 100 divides a first area 11 and a second area 12 on a first current collector 10, the first active layer 111 is disposed in the first area 11, and the first active layer 111 extends to the second area 12 to form a second active layer 121. In the embodiment of the present application, the ratio of the thickness of the second active layer 121 to the thickness of the first active layer 111 ranges from 80% to 100%.

Referring to fig. 1, in particular, the pole piece 100 further includes a first tab region 13, and the first tab region 13 is connected to the second region 12. Further, the first current collector 10 is substantially in a rectangular structure before being cut, the first tab area 13 is disposed at the edge of the second area 12 of the first current collector 10, and the length of the first tab area 13 is equal to the length of the edge of the second area 12.

Referring to fig. 2, the first current collector 10 coated with the active layer and the first tab region 13 are cut in a predetermined shape. The length of the first area 11 after cutting can be 50mm, 80mm or 100mm, and the specific length can be cut according to specific needs. The width of the second region 12 ranges from 4mm to 10mm, and in an embodiment of the present application, the width of the second region 12 may be 8 mm. The width of the first area 11 is the length of the second area 12, and the width of the first area 11 can be cut according to specific needs.

After the first tab area 13 is cut, a tab 131 is formed, wherein the length of the tab 131 is 9 +/-2 mm, and the width of the tab 131 is 8 +/-1 mm.

It is understood that in other embodiments, the second area 12, the first tab 131 may be sized and cut according to specific needs.

Referring to fig. 4, specifically, after the first active layer 111 and the second active layer 121 are respectively disposed on the first area 11 and the second area 12, the second area 12 and the first tab area 13 are cut. Specifically, the first tab area 13 is cut according to a preset size. The second area 12 is cut along the boundary between the second area 12 and the first area 11 in the longitudinal direction thereof, and only the portion of the first tab 131 connected to the second area is left after cutting. That is, by leaving the second region 12 on the first tab 131 after cutting, it can be shown that the pole piece 100 in the present application has a partially thinned area cut away so that the overall thickness of the pole piece 100 is substantially the same. The second active layer 121 remaining on the first tab 131 does not function after being fabricated into a cell, and thus does not affect the use of the cell.

It is to be understood that when cutting the second area 12 and the first tab area 13, the cutting device may first cut the first tab area 13 and further cut the portion other than the second area 12 connected to the first tab 131. In another embodiment, the cutting device may also preset the cutting size of the second area 12 and the first tab area 13, and cut the second area 12 and the first tab area 13 simultaneously.

Further, in the length direction of the first tab 131, the second active layer 121 of the second region 12 accounts for 3.6% to 20% of the first tab 131. In addition, the second active layer 121 cannot be excessively left on the first tab 131, and the first tab 131 needs to be electrically connected to other devices or components, so that a sufficient space needs to be left for the first tab 131 to be electrically connected.

Referring to fig. 5, it can be understood that, in other embodiments, the first current collector 10 may be provided in an L-shaped structure, an active layer is coated on the L-shaped first current collector 10, and then the pole piece 100 is cut in the same manner, so as to obtain the L-shaped pole piece 100. According to another embodiment of the present application, the first current collector 10 may be designed into other shapes according to actual requirements, including but not limited to T-shaped, i-shaped, circular or round-like shapes, and the like.

In the embodiment of the present application, the ratio of the thickness of the second active layer 121 to the thickness of the first active layer 111 is 100%.

Second embodiment

Referring to fig. 6, a pole piece 100 of the second embodiment is substantially the same as the first embodiment, except that in the second embodiment, the first tab region 13 is not disposed on the pole piece 100, and an insulating layer 14 is further disposed on a surface of the pole piece 100, wherein the insulating layer 14 is disposed on the second region 12, so that the second active layer 121 extending to an edge of the second region 12 extends toward the first region 11.

Specifically, the insulating layer 14 is disposed at an edge of a portion of the second region 12, and the second active layer 121 is formed in a process that the first active layer 111 extends to the second region 12, and the formed second active layer 121 continues to flow to the edge of the second region 12. At this time, the insulating layer 14 blocks the second active layer 121 from flowing further toward the edge of the second region 12, so that the second active layer 121 extends toward the opposite direction of the edge of the second region 12, i.e., toward the first region 11, due to the resistance. So that the thickness of the second active layer 121 on the second region 12 is approximately the same as the thickness of the first active layer 111 on the first region 11.

Further, the material of the insulating layer 14 includes ceramic, and the insulating layer 14 including the ceramic material has a barrier effect on the active layer. Therefore, the problem of the thin active layer of the second region 12 of the pole piece 100 can be improved.

In the embodiment of the present application, the ratio of the thickness of the second active layer 121 to the thickness of the first active layer 111 is 90%.

Third embodiment

Referring to fig. 7, a pole piece 100 of a third embodiment is substantially the same as the second embodiment, except that in the third embodiment, the pole piece 100 further includes a first tab region 13, and the first tab region 13 connects a side of the second region 12 away from the first region 11.

The insulating layer 14 may also be disposed on the first tab region 13. Specifically, the insulating layer 14 is partially disposed at an end position of the first tab region 13 close to the second region 12, and another portion of the insulating layer 14 is disposed on the second region 12 to block the flow of the second active layer 121. And then, after the insulating layer 14 is arranged on the first tab area 13 and the second tab area 12, the pole piece 100 is cut.

Referring to fig. 8, it can be understood that, in another embodiment, the insulation layer 14 may also be directly disposed on the first tab area 13, and then the second area 12 and the first tab area 13 are cut.

In the embodiment of the present application, the ratio of the thickness of the second active layer 121 to the thickness of the first active layer 111 is 80%.

Fourth embodiment

Referring to fig. 9, a fourth embodiment of the present application provides an electrode assembly 200, where the electrode assembly 200 includes a plurality of first and second pole pieces 20, and the first pole piece is the pole piece 100 in the above embodiment. The first pole piece is an anode pole piece, and the second pole piece 20 is a cathode pole piece. The electrode assembly 200 further includes a separator 22, the first and second electrode plates 20 are spaced apart from each other, and the separator 22 is disposed between the first and second electrode plates 20. The second tab 20 further includes a second tab 21, and the second tab 21 and the first tab 131 are located at the same end of the electrode assembly 200. The electrode assembly 200 is formed by alternately stacking the first and second electrode sheets 20. According to another embodiment of the present application, the electrode assembly 200 may be formed by winding the first and second pole pieces 20 stacked in layers.

Fifth embodiment

Referring to fig. 10, a battery 300 according to a fifth embodiment of the present application includes a case 30 and an electrode assembly 200 according to the third embodiment, wherein the electrode assembly 200 is accommodated in the case 30. The battery 300 is filled with an electrolyte, which infiltrates the electrode assembly 200.

Sixth embodiment

Referring to fig. 11, a sixth embodiment of the present application provides an electric device 400, where the electric device 400 includes a body 40 and a battery 300 of the fourth embodiment, and the battery 300 is disposed in the body 40. In fig. 11, a mobile tool is taken as an example, the body 40 is a housing of the mobile tool, and the battery 300 is disposed inside the housing to supply power to the mobile tool. It is understood that in other embodiments, the powered device 400 may also be an intelligent appliance, an electric vehicle, or the like.

In summary, the present application provides a pole piece 100, in order to eliminate the problem that the thicknesses of the active layers of the first region 11 and the second region 12 on the pole piece 100 are different, the second region 12 is cut off to solve the problem. Alternatively, an insulating layer 14 is disposed on the pole piece 100 to block the second active layer 121 from flowing further to the edge of the second region 12, thereby increasing the thickness of the active layer on the second region 12. In this way, the thicknesses of the active layers of the first region 11 and the second region 12 are consistent, and the problem of unbalanced battery in the process of manufacturing the battery is avoided.

In addition, those skilled in the art should recognize that the foregoing embodiments are illustrative only, and not limiting, and that appropriate changes and modifications can be made without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

A pole piece, comprising:

a first region;

a second region connecting the first region; and

the first active layer is arranged in the first area, extends to the second area to form a second active layer, and the proportion of the thickness of the second active layer to the thickness of the first active layer ranges from 80% to 100%.
The pole piece of claim 1 further comprising a first tab, said first tab being joined to said second region, a portion of said second active layer being coated on said first tab.
The pole piece of claim 2, wherein the second active layer is coated in a distance ranging from 0.4mm to 1.4mm in a length direction of the first tab.
The pole piece of claim 3, wherein the second active layer accounts for 3.6% to 20% of the first tab in the lengthwise direction of the first tab.
The pole piece of claim 1, wherein the surface of the pole piece is further provided with an insulating layer, the insulating layer is disposed on the edge of the second region away from the first region, so that the second active layer extending to the edge of the second region extends toward the first region.
The pole piece of claim 5, wherein the material of the insulating layer comprises a ceramic.
The pole piece of claim 1, wherein the second region has a width in a range of 4mm to 10 mm.
The pole piece of claim 7, wherein the second region has a width of 8 mm.
An electrode assembly comprising a plurality of first and second electrode sheets, the first electrode sheet being as defined in any one of claims 1 to 8, the first and second electrode sheets being spaced apart and the first and second electrode sheets being laminated or wound to form the electrode assembly.
A battery comprising a case and an electrode assembly as claimed in claim 9, the electrode assembly being housed in the case.
An electrical device comprising a body and the battery of claim 10, wherein the battery is disposed within the body.