WO2021195851A1

WO2021195851A1 - Pole piece, electrode assembly using same, battery, and power utilization device

Info

Publication number: WO2021195851A1
Application number: PCT/CN2020/082116
Authority: WO
Inventors: 连旭宸; 王佳伟; 李�瑞; 江行国
Original assignee: 宁德新能源科技有限公司
Priority date: 2020-03-30
Filing date: 2020-03-30
Publication date: 2021-10-07
Also published as: CN113812016B; CN113812016A

Abstract

The present application provides a pole piece, comprising: a first region; a second region connected to the first region; and a first active layer provided in the first region, wherein the first active layer extends to the second region to form a second active layer, and the range of the ratio of the thickness of the second active layer to the thickness of the first active layer is 80-100%. The present application further relates to an electrode assembly, a battery, and a power utilization device. By using the pole piece, the condition that the edge of the pole piece is thin can be improved, thereby improving the safety of the pole piece.

Description

Pole piece, electrode assembly using the pole piece, battery and electric device

Technical field

This application relates to the field of battery technology, in particular to a pole piece, an electrode assembly using the pole piece, a battery and an electrical device.

Background technique

In the process of producing batteries, coating on the pole pieces is an indispensable process. In the process of coating the pole piece, the active material flows on the current collector. It is inevitable that after the active material flows on the current collector, the active material at the edge of the current collector will level out, that is, the active material on the current collector. The thickness is different. As a result, there is a thinned area on the edge of the pole piece. The thinned area is located at the head of the cell. Because this area is thin, that is, there is less active material. When the pole piece is made into a battery, the battery has an imbalance of active material. This leads to safety issues.

Summary of the invention

In view of this, it is necessary to provide a pole piece, an electrode assembly using the pole piece, a battery, and an electrical device to ensure the balance of active materials inside the battery.

A pole piece, including:

First area

The second area is connected to the first area; and

The first active layer is disposed in the first area, the first active layer extends to the second area to form a second active layer, and the thickness of the second active layer is the same as the thickness of the first active layer The ratio ranges from 80% to 100%.

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

In at least one embodiment, the coating distance of the second active layer in the length direction of the first tab ranges from 0.4 mm to 1.4 mm.

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

In at least one embodiment, an insulating layer is further provided on the surface of the pole piece, and the insulating layer is provided on the edge of the second area away from the first area, so that the area extending to the edge of the second area The second active layer then extends toward the first area.

In at least one embodiment, the material of the insulating layer includes ceramics.

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

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

An electrode assembly, the electrode assembly includes a plurality of first pole pieces and second pole pieces, the first pole pieces are the above-mentioned pole pieces, and the first pole pieces and the second pole pieces are arranged at intervals, And the first pole piece and the second pole piece are laminated or wound to form the electrode assembly.

A battery includes a casing and the above-mentioned electrode assembly, and the electrode assembly is accommodated in the casing.

An electric device includes a main body and the above-mentioned battery, and the battery is arranged in the main body.

The pole piece provided by the present application solves the problem of the thinning area on the pole piece by keeping the ratio of the thickness of the active layer on the first area and the second area between 80% and 100%. Keeping the thickness of the active layer on the first area and the second area approximately the same, so that the amount of active material in the first area and the second area on the pole piece remains approximately the same, which improves the safety of the pole piece during use.

Description of the drawings

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

Fig. 2 is a schematic plan view of the pole piece after being cut in the first embodiment.

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 cutting in the first embodiment.

Fig. 5 is a schematic plan view of another form of pole piece in the first embodiment.

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

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

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

Fig. 9 is a perspective view of the electrode assembly of the fourth embodiment.

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

Fig. 11 is a three-dimensional schematic diagram of an electrical device of a sixth embodiment.

Symbol description of main components

Polar piece 100

The first episode of fluid 10

The first zone 11

The first active layer 111

The second zone 12

The second active layer 121

The first pole area 13

First pole ear 131

Insulation layer 14

Electrode assembly 200

The second pole piece 20

The second pole ear 21

Isolation film 22

Battery 300

Shell 30

Power consuming device 400

Ontology 40

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.

It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to another component or a centered component may exist at the same time. When a component is considered to be "installed on" another component, it can be directly installed on the other component or a centered component may exist at the same time. The terms "top", "bottom", "upper", "lower", "left", "right", "front", "rear" and similar expressions used herein are for illustrative purposes only.

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.

The present application provides a pole piece, including a first area, a second area, and a first active layer. The second area is connected to the first area. The first active layer is disposed in the first area. The first active layer extends to the second region to form a second active layer, and the ratio of the thickness of the second active layer to the thickness of the first active layer ranges from 80% to 100%.

By using the above-mentioned pole piece, the problem caused by the thinned area on the edge of the pole piece is effectively solved, and the difference in the ratio of the active material between the pole pieces is reduced, thereby maintaining the The balance of active materials increases the safety of the battery.

Hereinafter, some implementation manners of the present application will be described in detail. In the case of no conflict, the following implementation manners, that is, the features in the implementation manners, can be combined with each other.

Comparative example

Please refer to Figure 1, Figure 2 and Figure 3, a pole piece 100 includes a first current collector 10, a first region 11 and a second region 12, the first region 11 and the second region 12 are in the Two areas are divided on the first current collector 10, and the second area 12 is connected to the first area 11. The pole piece 100 further includes a first active layer 111, the first active layer 111 is disposed on the first area 11, and the first active layer 111 extends to the second area 12 to form a second The active layer 121, the thickness of the second active layer 121 is smaller than the thickness of the first active layer 111. That is, the second area 12 on the first current collector 10 forms a thinned area.

Specifically, the first area 11 and the second area 12 jointly constitute the upper surface of the first current collector 10, and the first area 11 occupies a relatively large area on the first current collector 10. The second area 12 is an area where the first current collector 10 is approximately located at the edge, and occupies a relatively small 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 is coated on the first area 11, and the first active layer 111 is formed on the The flow on the first region 11, and the thickness of the first active layer 111 located on the first region 11 is substantially uniform. The first active layer 111 flows to the second region 12 to form the second active layer 121, the thickness of the second active layer 121 is smaller than the thickness of the first active layer 111, and the second active layer The closer the thickness of the layer 121 is to the edge of the second region 12, the thinner the thickness.

The above content is the situation that occurred during the process of making the pole piece 100. The first current collector 10 forms a thinned area. During the use of this type of pole piece 100, the second area 12 is The active layer at the edge is too thin, which leads to the fact that when the pole piece 100 is used as the anode pole piece, the ratio of the active material on the anode pole piece to the cathode pole piece in the manufactured battery is less than 1, which causes the battery to produce lithium evolution phenomenon, which leads to There is a security problem.

The first embodiment

In order to solve the situation that a thinned area is formed at the edge position of the pole piece 100, the present application provides a pole piece 100. The pole piece 100 uses the same method as in the comparative embodiment to divide the first current collector 10 on the first current collector. In the region 11 and the second region 12, the first active layer 111 is disposed in the first region 11, and the first active layer 111 extends to the second region 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%.

Please refer to FIG. 1, specifically, 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 has a substantially rectangular structure before being cut, the first tab region 13 is provided on the edge of the second region 12 of the first current collector 10, and the first The length of a tab region 13 is equal to the length of the edge of the second region 12.

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

After the first tab area 13 is cut, a tab 131 is formed. The tab 131 has a length of 9±2 mm and a width of 8±1 mm.

It can be understood that, in other embodiments, the size of the second region 12 and the first tab 131 can be cut according to specific needs.

4, specifically, after the first active layer 111 and the second active layer 121 are respectively provided on the first area 11 and the second area 12, then the second area 12 and the first tab area 13 are cut. The specific cutting method is that the first tab area 13 is cut according to a preset size. The second area 12 is cut according to its length direction and along the boundary line between the second area 12 and the first area 11, leaving only the cut first tab 131 The part connected to the second area. That is, by leaving the second area 12 on the cut first tab 131, it can be shown that the pole piece 100 in the present application has cut off a part of the thinned area, so that the overall thickness of the pole piece 100 is approximately the same. . The second active layer 121 remaining on the first tab 131 will not play a role after being fabricated into a battery cell, so that it will not affect the use of the battery cell.

It is understandable that when cutting the second region 12 and the first tab region 13, the cutting device may first cut the first tab region 13 and further align with the first tab 131 The parts other than the connected second area 12 are cut. In another embodiment, the cutting device can also preset the cutting size of the second region 12 and the first tab region 13, and adjust the size of the second region 12 and the first tab region. The ear area 13 is simultaneously cut.

Further, in the length direction of the first tab 131, the ratio of the second active layer 121 of the second region 12 to the first tab 131 is 3.6% to 20%. In addition, the second active layer 121 cannot be left too much on the first tab 131, because the first tab 131 also needs to be electrically connected with other devices or components, so it needs to be set aside There is enough space for the first tab 131 to be used for electrical connection.

Referring to FIG. 5, it can be understood that, in other embodiments, the first current collector 10 may be arranged in an L-shaped structure, and an active layer is coated on the L-shaped first current collector 10, and then the same The pole piece 100 is cut in the manner of, and finally an L-shaped pole piece 100 is obtained. According to another embodiment of the present application, the first current collector 10 can be designed in other shapes according to actual needs, including but not limited to T-shaped, I-shaped, circular or similar-circular shapes.

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, the pole piece 100 of the second embodiment is substantially the same as the first embodiment, except that, in the second embodiment, the pole piece 100 is not provided with the first tab region 13, and An insulating layer 14 is further provided on the surface of the pole piece 100, and the insulating layer 14 is provided on the second region 12 so that the second active layer 121 extending to the edge of the second region 12 faces the The first area 11 extends.

Specifically, the insulating layer 14 is provided on a part of the edge of the second region 12, and the second active layer 121 is formed in the process of extending the first active layer 111 to the second region 12, so The formed second active layer 121 will continue to flow to the edge of the second region 12. At this time, the insulating layer 14 blocks the second active layer 121 from continuing to flow toward the edge of the second region 12, so that the second active layer 121 faces the second region 12 due to resistance. The edges extend in the opposite direction, that is, extend toward the first region 11. The thickness of the second active layer 121 on the second region 12 is substantially 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 ceramics, and the insulating layer 14 including ceramic materials has an obstructive effect on the active layer. Therefore, the problem that the active layer of the second region 12 of the pole piece 100 is thin 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%.

The third embodiment

Referring to FIG. 7, the pole piece 100 of the third embodiment is substantially the same as the second embodiment. The difference is that, in the third embodiment, the pole piece 100 further includes a first tab region 13, and the second embodiment A tab area 13 is connected to a side of the second area 12 away from the first area 11.

The insulating layer 14 may also be disposed on the first tab area 13. Specifically, the insulating layer 14 is partially disposed at the end of the first tab region 13 close to the second region 12, and another part of the insulating layer 14 is disposed on the second region 12 to The flow of the second active layer 121 is blocked. After the insulating layer 14 is disposed on the first tab region 13 and the second region 12, the pole piece 100 is cut.

Referring to FIG. 8, it can be understood that, in another embodiment, the insulating layer 14 can also be directly provided on the first tab region 13, and then the second region 12 and the first The tab area 13 is 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. The electrode assembly 200 includes a plurality of first pole pieces and second pole pieces 20, and the first pole pieces are the ones in the above embodiments. Pole piece 100. 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 an isolation film 22, the first pole piece and the second pole piece 20 are spaced apart, and the isolation film 22 is provided on the first pole piece and the second pole piece 20 between. The second pole piece 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 pole pieces and the second pole pieces 20. According to another embodiment of the present application, the electrode assembly 200 may be formed by winding the stacked first pole piece and the second pole piece 20.

Fifth embodiment

10, a fifth embodiment of the present application provides a battery 300, the battery 300 includes a housing 30 and the electrode assembly 200 in the third embodiment, the electrode assembly 200 is accommodated in the housing 30 . The battery 300 is filled with electrolyte, and the electrolyte infiltrates the electrode assembly 200.

Sixth embodiment

Referring to FIG. 11, a sixth embodiment of the present application provides an electric device 400. The electric device 400 includes a main body 40 and a battery 300 in the fourth embodiment. The battery 300 is provided in the main body 40. In FIG. 11, taking a mobile tool as an example, the body 40 is a casing of the mobile tool, and the battery 300 is provided inside the casing to supply power to the mobile tool. It can be understood that, in other embodiments, the electric device 400 may also be a smart home appliance, an electric vehicle, or the like.

In summary, the pole piece 100 provided in the present application eliminates the problem of the difference in the thickness of the active layer of the first region 11 and the second region 12 on the pole piece 100, and the second region 12 is cut out to solve the problem. . Alternatively, an insulating layer 14 is provided on the pole piece 100 to block the second active layer 121 from continuing to flow 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 thickness of the active layer of the first region 11 and the second region 12 is made uniform, and the problem of battery imbalance in the process of manufacturing the battery is avoided.

In addition, those of ordinary skill in the art should realize that the above implementations are only used to illustrate the application, and not to limit the application, as long as the above embodiments are within the scope of the essential spirit of the application. Appropriate changes and changes fall within the scope of protection claimed by this application.

Claims

A pole piece, characterized in that it comprises:

First area

The second area is connected to the first area; and

The first active layer is disposed in the first area, the first active layer extends to the second area to form a second active layer, and the thickness of the second active layer is the same as the thickness of the first active layer The ratio ranges from 80% to 100%.
The pole piece according to claim 1, wherein the pole piece further comprises a first tab, the first tab is connected to the second area, and a part of the second active layer is coated on the On the first pole ear.
The pole piece according to claim 2, wherein the coating distance of the second active layer in the length direction of the first pole lug ranges from 0.4 mm to 1.4 mm.
The pole piece according to claim 3, wherein in the length direction of the first tab, the proportion of the second active layer in the first tab is 3.6% to 20%.
The pole piece according to claim 1, wherein the surface of the pole piece is further provided with an insulating layer, and the insulating layer is provided on the edge of the second area away from the first area so as to extend to The second active layer at the edge of the second area extends toward the first area.
The pole piece according to claim 5, wherein the material of the insulating layer includes ceramics.
The pole piece according to claim 1, wherein the width of the second area ranges from 4 mm to 10 mm.
The pole piece according to claim 7, wherein the width of the second area is 8 mm.
An electrode assembly, wherein the electrode assembly includes a plurality of first pole pieces and second pole pieces, the first pole pieces being the pole pieces according to any one of claims 1 to 8, and The first pole piece and the second pole piece are arranged at intervals, and the first pole piece and the second pole piece are laminated or wound to form the electrode assembly.
A battery characterized by comprising a casing and the electrode assembly as claimed in claim 9, and the electrode assembly is accommodated in the casing.
An electrical device characterized by comprising a main body and the battery according to claim 10, and the battery is arranged in the main body.