CN216015424U

CN216015424U - Pole piece and battery comprising same

Info

Publication number: CN216015424U
Application number: CN202121812780.1U
Authority: CN
Inventors: 尚贞西; 张仔伟; 韩晓辉; 廖兴群
Original assignee: Huizhou Highpower Technology Co Ltd
Current assignee: Huizhou Highpower Technology Co Ltd
Priority date: 2021-08-04
Filing date: 2021-08-04
Publication date: 2022-03-11
Anticipated expiration: 2031-08-04

Abstract

The utility model provides a pole piece and a battery comprising the pole piece, wherein the pole piece comprises a current collector and an active substance layer, the active substance layer covers at least one surface of the current collector, and the active substance layer is provided with a tab groove which is exposed out of the surface of the current collector and has a polygonal cross section, and at least one corner is a fillet; the pole piece is a coated pole piece or a rolled pole piece or a stripped pole piece; the pole lug groove with the shape can effectively relieve the acting force of the pole piece on the current collector at the position of the pole lug groove due to the stress action of the pole piece in the processes of rolling, splitting and producing the pole piece, so that the occurrence of the wrinkle condition of the current collector at the position of the pole lug groove is reduced, the quality appearance of the pole piece is improved, the welding goodness of the pole lug in the post process is reduced, the polarization of the battery is reduced, the temperature rise of the battery is reduced, and the energy density, the electrochemical performance and the safety performance of the lithium ion battery are improved.

Description

Pole piece and battery comprising same

Technical Field

The utility model belongs to the technical field of lithium ion batteries, and particularly relates to a pole piece and a battery comprising the pole piece.

Background

Lithium ion batteries have been widely used in the fields of consumer electronics, electric vehicles, etc. because of their advantages of high energy density, long cycle life, no memory effect, etc. With the continuous development of lithium ion battery technology, higher requirements are put forward on the performance of lithium ion batteries, for example, we want lithium ions to have smaller volume, faster charge and discharge, lower temperature rise, higher energy density, and the like.

In the conventional design of the lithium ion battery, the tab is positioned on the empty foil of the coating gap of the pole piece, and the lithium ion battery prepared by the pole piece with the structural design has low energy density. In order to improve the energy density of the lithium ion battery, the tab welding process is optimized, namely, a groove suitable for tab welding is cleaned in an appointed area of a pole piece through laser, the size of the groove is slightly larger than the area of the tab in the pole piece welding area, the introduction of the process can improve the utilization rate of a pole piece current collector, and the process has positive significance for improving the energy density of the battery, reducing the temperature rise and improving the charging and discharging speed; but the utmost point ear trench that laser washout was mostly regular right-angled rectangle, the pole piece of welding utmost point ear is waiting can transmit utmost point ear trench because of the stress action of pole piece when roll-in, divide strip and film-making, and the foil of utmost point ear recess can produce tensile under great stress action, and the anomalous effort in direction can make the foil of recess produce serious fold, reduces the pole piece quality, reduces utmost point ear welding goodness, also can produce very big influence to the electrochemistry and the security performance of battery.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the technical problems that the laser-cleaned foil folds in regular right-angle rectangular groove positions reduce the quality of a pole piece, reduce the welding quality rate of a pole lug and have great influence on the electrochemistry and safety performance of a battery.

The utility model provides a pole piece which comprises a current collector and an active substance layer, wherein the active substance layer covers at least one surface of the current collector, a lug groove leaking out of the surface of the current collector is formed in the active substance layer, the cross section of the lug groove is polygonal, and at least one corner of the polygon is a round corner.

Optionally, all corners of the polygon are rounded.

Optionally, the number of the tab grooves is multiple.

Optionally, the shape of the lug groove is quadrilateral.

Optionally, the cross-sectional shape of the tab groove is rectangular.

Optionally, the active material layer cover in two surfaces of the mass flow body, two surfaces of the mass flow body all are provided with utmost point ear recess.

Optionally, the positions of the lug grooves on the two surfaces of the current collector are staggered with each other.

Optionally, the positions of the lug grooves on the two surfaces of the current collector coincide.

Optionally, the pole piece is a coated pole piece, a rolled pole piece or a stripped pole piece.

The utility model provides a battery, which comprises a positive plate, a negative plate and electrolyte, wherein the electrolyte infiltrates the positive plate and the negative plate, and the positive plate and/or the negative plate are/is independently selected from the plate.

The utility model provides a pole piece and a battery comprising the pole piece, wherein the pole piece comprises a current collector and an active substance layer, the active substance layer covers at least one surface of the current collector, the active substance layer is provided with a pole lug groove, the cross section of the pole lug groove is polygonal, and at least one corner of the pole lug groove is a fillet.

Drawings

Fig. 1 is a schematic view of a tab groove structure formed on an active material layer in the prior art;

fig. 2 is a schematic view illustrating a tab groove structure formed in an active material layer according to an embodiment of the present invention;

fig. 3 is a schematic diagram of a rectangular structure of a tab groove;

the reference numbers in the drawings of the specification are as follows:

1. a tab groove; 21. an active material layer; 22. a current collector; 3. and (4) rounding.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the utility model and are not intended to limit the utility model.

As shown in fig. 1, the shape of the welding groove adapted to the tab is cleaned for the designated position area of the laser on the active material layer in the prior art, and the size of the groove is slightly larger than the area of the welding area of the tab on the active material layer. As shown in figure 1 the shape of utmost point ear recess be four angular all right angled rectangles, four angular all right angled regular rectangles through laser cleaning, the pole piece is through the roll-in, divide the strip, during subsequent processes such as film-making, the pole piece need pass through various running rollers, press from both sides the rod, stretching device, laser cleaning's utmost point ear recess does not have the active material coating, the mass flow body of this utmost point ear groove position, and near pole piece atress size and direction are different, the mass flow body of utmost point ear groove position can produce not tensile of equidimension, when passing the roller, stress release, the easy fold of mass flow body of utmost point ear groove position, near the pole piece material phenomenon appears falling when serious, reduce the pole piece quality. The current collector at the position of the lug groove is wrinkled, so that welding is difficult, the current collector is severely wrinkled and cracked, and the welding yield of the lug is reduced; the current collector is folded, and the polarization of the prepared lithium ion battery is increased, so that the electrochemical performance and the safety performance of the lithium ion battery are greatly influenced.

In order to solve the above problems, as shown in fig. 2 to 3, an embodiment of the present invention provides a pole piece and a battery including the pole piece, where the pole piece includes a current collector 22 and an active material layer 21, the active material layer 21 covers at least one surface of the current collector 22, a tab recess 1 leaking out of the surface of the current collector 22 is formed in the active material layer 21, a cross-sectional shape of the tab recess 1 is a polygon, and at least one corner of the polygon is a rounded corner 3. In this embodiment, the thickness of the current collector 22 coated with the active material layer 21 is different from that of the current collector 22 not coated with the active material layer 21, and if the tension applied by the stretching is different, the position of the current collector 22 not coated with the active material layer 21 is more likely to be wrinkled during the stress release. In the pole piece provided by the utility model, the active substance layer 21 is provided with the pole lug groove 1 which is leaked out of the surface of the current collector 22, the cross section of the pole lug groove 1 is polygonal, at least one corner of the polygon is a fillet 3, the fillet 3 can effectively relieve the acting force of the pole piece on the current collector 22 at the pole lug groove 1 due to the stress action of stretching the pole piece in the post-processes of rolling, splitting, sheet making and the like, the occurrence of the wrinkling condition of the current collector 22 at the pole lug groove 1 due to different acting force sizes and directions is reduced, the quality appearance of the pole piece is improved, the pole lug welding goodness in the post-process is reduced, the polarization of the battery is reduced, the temperature rise of the battery is reduced, and the energy density, the electrochemical performance and the safety performance of the lithium ion battery are improved.

In this embodiment, one corner of the polygon is a rounded corner 3, multiple corners may be rounded corners 3, or all corners may be rounded corners 3. The more the number of the fillets 3 is, the better the effect of relieving the acting force is achieved by the prepared pole piece with the pole lug groove 1.

The active material layer 21 is provided with a plurality of tab grooves 1 leaking out of the surface of the current collector 22; the number of the lug grooves 1 is set according to the required welding number of the lugs during the design of the lithium ion battery. The present invention is not limited, and the number of the tab recesses 1 may be set according to the capacity, charging requirement, energy density, etc. of the lithium ion battery to be produced.

The shape of the tab groove 1 can be quadrilateral; the section of the tab groove 1 is rectangular. For a lithium ion battery, in order to improve the energy density of the lithium ion battery and fully utilize foil as much as possible, the tab groove 1 recited in an embodiment of the present invention is quadrilateral and regular rectangular, the rectangle is also designed according to the size of a tab, and the width of the rectangle is only slightly larger than that of the tab, so as to facilitate tab welding; the design width of the lug groove can be as small as possible, so long as the lug is not welded on the lug during welding, foil materials are fully utilized, and the energy density of the lithium ion battery is improved as far as possible.

As shown in fig. 3, the shape of the tab recess 1 is a rectangle, at least one corner in the tab recess 1 is a fillet 3, two corners are fillets, three corners are fillets, and four corners are fillets, and the number of the fillets 3 can be adjusted and set according to actual process conditions. The diameter R of the rounded corner 3 is required to be larger than 0, and as shown in fig. 3, when the diameter R of the rounded corner 3 is 1/2 rectangular sides, the rectangular sides are a large circular arc with a radius R. The diameter R of the fillet 3 can be adjusted according to the process requirement conditions in the actual production process. The more the number of fillets 3, the larger the diameter R is, the less the folds of the foil surface at the lug groove 1 are, and the more obvious the improvement condition is.

In an embodiment of the present invention, the active material layer 22 covers two surfaces of the current collector 21, and both surfaces of the current collector 21 are provided with tab recesses 1. In the lithium ion battery production process, in order to promote the volume energy density of battery, quality energy density, two surfaces of mass collector 21 all are provided with active substance layer 22, and in this embodiment, a surface of mass collector 21 sets up utmost point ear recess 1, can also be that two surfaces of mass collector 21 are provided with utmost point ear recess 1. In an embodiment of the present invention, the positions of the tab recesses 1 on the two surfaces of the current collector 21 may be staggered or overlapped, which is not specifically limited in the present invention, and the position distribution of the tab recesses 1 may be set according to the actual situation of the pole piece in the actual production process.

In this embodiment, the pole piece may be a coated pole piece, a rolled pole piece, or a striped pole piece, and the utility model does not specifically limit which process the pole piece is. In this embodiment, the tab groove 1 is obtained by cleaning the active material layer 22 at a certain position of the pole piece, wherein the cleaning technology includes one or more of laser, electrostatic generator and electrochemical cleaning.

An embodiment of the utility model provides a lithium ion battery, which comprises a positive plate, a negative plate and electrolyte, wherein the positive plate and the negative plate adopt the above-mentioned plate structures.

This embodiment provides a pole piece and its acquisition and working process:

a: selecting the coated pole piece, and firstly determining the position of a tab groove 1 on the pole piece. B: and cleaning the active material layer 22 at the position of the groove 1 of the pole piece by using a laser technology. C: according to the process requirement, the lug grooves 1 with the fillets 3 are cleaned on the two active material layers 22 of the pole piece, and the lug grooves 1 are rectangular; cleaning one tab groove 1 on the surface of each of the two active material layers 22, wherein the two tab grooves 1 are staggered; the number of fillet 3 is 2, diameter R is 1/2 rectangle length of side, and the number of utmost point ear recess 1 is 2. D: then, through the processes of rolling, splitting and preparation, welding the tab to the corresponding tab groove 1 position; and then, preparing the lithium ion battery through processes such as liquid injection and the like.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the utility model, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims

1. The utility model provides a pole piece, its characterized in that, includes mass flow body and active substance layer, active substance layer cover in at least one surface on the mass flow body, seted up on the active substance layer and spilt the utmost point ear recess on mass flow body surface, the cross-sectional shape of utmost point ear recess is the polygon, at least one angle of polygon is the fillet.

2. A pole piece as claimed in claim 1, wherein all corners of said polygon are rounded.

3. A pole piece as claimed in claim 1, wherein the number of tab recesses is plural.

4. A pole piece as claimed in claim 1, wherein the lug recess is quadrilateral in shape.

5. A pole piece as claimed in claim 4, wherein the cross-sectional shape of the tab recess is rectangular.

6. The pole piece of claim 1, wherein the active material layer covers two surfaces of the current collector, and the two surfaces of the current collector are provided with tab grooves.

7. A pole piece according to claim 6, wherein the lug grooves on both surfaces of the current collector are offset in position from each other.

8. A pole piece according to claim 6, wherein the position of the lug grooves on both surfaces of the current collector coincide.

9. The pole piece of claim 8, wherein the pole piece is a coated pole piece or a rolled pole piece or a stripped pole piece.

10. A battery comprising a positive plate, a negative plate and an electrolyte, wherein the electrolyte infiltrates the positive plate and the negative plate, and the positive plate and/or the negative plate are each independently selected from the plates of any one of claims 1 to 9.