CN215451466U

CN215451466U - Pole piece rolling device and lithium battery production line

Info

Publication number: CN215451466U
Application number: CN202120830173.1U
Authority: CN
Inventors: 刘超; 吴志亮; 贺梦江
Original assignee: Sunwoda Electric Vehicle Battery Co Ltd
Current assignee: Xinwangda Power Technology Co ltd
Priority date: 2021-04-21
Filing date: 2021-04-21
Publication date: 2022-01-07
Anticipated expiration: 2031-04-21

Abstract

The application discloses pole piece roll-in device and lithium cell production line. The utility model provides a pole piece roll-in device is used for rolling in the pole piece, including the unwinding mechanism who is used for releasing the pole piece, the winding mechanism of roll-up pole piece, first roll-in mechanism and second roll-in mechanism set up on the tape transport route of pole piece, the first roll-in wheel of first roll-in mechanism and the coating area of second roll-in wheel combined action roll-in pole piece, second roll-in mechanism includes the roll-in subassembly, the third roll-in wheel and the fourth roll-in wheel combined action of roll-in subassembly, the third roll-in wheel and the fifth roll-in wheel combined action of roll-in subassembly, roll-in the blank area to the pole piece, the quantity of roll-in subassembly is the same with the quantity of blank area, eliminate the pole piece fold condition when the pole piece roll-in device of this application can stretch the pole piece, avoid the pole piece fracture. The lithium battery production line with the pole piece rolling device can improve the product quality and improve the production efficiency.

Description

Pole piece rolling device and lithium battery production line

Technical Field

The application relates to the field of power batteries, in particular to a pole piece rolling device and a lithium battery production line.

Background

In the field of power batteries, reducing the thickness of a substrate is one of the effective methods for increasing the capacity density. In the related art, a rolling device is generally used to thin the pole piece to improve the energy density of the battery. The pole piece includes blank area and coating area, and the thickness in coating area is greater than the thickness in blank area, and the in-process of roll-in, roll-in device are used in the coating area of pole piece, and coating area pressurized extension, and blank area does not receive roller pressure, and blank area can not extend, and blank area and coating area's ductility difference is big, produces the fold phenomenon easily to the broken tape of inducing the pole piece.

SUMMERY OF THE UTILITY MODEL

The present application is directed to solving at least one of the problems in the prior art. Therefore, the application provides a pole piece rolling device, can reduce the ductility difference in pole piece blank area and coating zone to reduce the emergence of pole piece fold disconnected area.

This application still provides a lithium cell production line that has above-mentioned pole piece roll-in device.

According to the first aspect of the application, the pole piece rolling device is used for rolling the pole piece, and comprises:

the unwinding mechanism is used for releasing the pole piece;

the winding mechanism is used for winding the pole piece;

the first rolling mechanism is arranged on a tape travelling path of the pole piece and comprises a first rolling wheel and a second rolling wheel, and the first rolling wheel and the second rolling wheel jointly roll a coating area of the pole piece;

the second rolling mechanism is arranged on a tape path of the pole piece and comprises a rolling assembly, the rolling assembly comprises a third rolling wheel, a fourth rolling wheel and a fifth rolling wheel, the third rolling wheel and the fourth rolling wheel act together, the third rolling wheel and the fifth rolling wheel act together to roll the blank area of the pole piece, and the rolling assembly is in the same quantity as the blank area.

The pole piece rolling device according to the application embodiment has at least the following beneficial effects: the extensibility difference between the blank area and the coating area of the pole piece can be reduced, so that the occurrence of the wrinkle and belt breakage of the pole piece is reduced.

According to some embodiments of the present application, the second rolling mechanism is disposed at least one of upstream of the first rolling mechanism or downstream of the first rolling mechanism.

According to some embodiments of the present application, the rolling assembly further comprises a driving member connected to the third rolling wheel for driving the third rolling wheel to approach or depart from the fourth rolling wheel and the fifth rolling wheel.

According to some embodiments of the application, the axis of third roller with the plane at the axis place of fourth roller is first plane, the axis of third roller with the plane at the axis place of fifth roller is the second plane, first plane with the contained angle on second plane is first contained angle, second roller still includes adjustment mechanism, adjustment mechanism's quantity with the quantity of roll-in subassembly is the same, adjustment mechanism can adjust the fourth roller with the position of at least one in the fifth roller is in order to change the angle of first contained angle.

According to some embodiments of the present application, the number of the second rolling mechanisms is at least 2.

According to some embodiments of the application, every in the second rolling mechanism, the axis of third pinch roller with the plane at the axis place of fourth pinch roller is first plane, the axis of third pinch roller with the plane at the axis place of fifth pinch roller is the second plane, first plane with the contained angle on second plane is first contained angle, follows the path of taking, second rolling mechanism first contained angle crescent.

According to some embodiments of the present application, the third roller is an elastic roller.

According to some embodiments of the present application, the fourth and fifth rollers are both metal rollers.

According to some embodiments of the present application, the second rolling mechanism further comprises a pass roller disposed upstream of the rolling assembly.

According to the embodiment of the second aspect of the present application, the lithium battery production line comprises the pole piece rolling device of the embodiment of the first aspect.

Additional aspects and advantages of the present application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the present application.

Drawings

The present application is further described with reference to the following figures and examples, in which:

FIG. 1 is a schematic structural diagram of a pole piece;

FIG. 2 is a schematic structural diagram of a pole piece rolling device according to an embodiment of the present application;

FIG. 3 is a schematic structural view of the second rolling mechanism in FIG. 2;

fig. 4 is a schematic sectional view taken along line a-a in fig. 3.

Reference numerals:

unwinding mechanism 100 winding mechanism 200 first rolling mechanism 300 first rolling wheel 310 second rolling wheel 320

Second rolling mechanism 400 rolling component 410 third rolling wheel 411, fourth rolling wheel 412, fifth rolling wheel 413

Adjusting mechanism 420 roller 430 pole piece 500 coating area 510 blank area 520

Detailed Description

Reference will now be made in detail to embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining the present application and are not to be construed as limiting the present application.

In the description of the present application, it is to be understood that the positional descriptions, such as the directions of up, down, front, rear, left, right, etc., referred to herein are based on the directions or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, and do not indicate or imply that the referred device or element must have a specific direction, be constructed and operated in a specific direction, and thus, should not be construed as limiting the present application.

In the description of the present application, the meaning of a plurality is one or more, the meaning of a plurality is two or more, and the above, below, exceeding, etc. are understood as excluding the present number, and the above, below, within, etc. are understood as including the present number. If the first and second are described for the purpose of distinguishing technical features, they are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.

In the description of the present application, unless otherwise expressly limited, terms such as set, mounted, connected and the like should be construed broadly, and those skilled in the art can reasonably determine the specific meaning of the terms in the present application by combining the detailed contents of the technical solutions.

In the description of the present application, reference to the description of the terms "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The pole piece rolling device according to the embodiment of the first aspect of the present application is described below with reference to the accompanying drawings.

The pole piece rolling device is used for rolling a pole piece 500 and comprises an unreeling mechanism 100, a reeling mechanism 200, a first rolling mechanism 300 and a second rolling mechanism 400, wherein the unreeling mechanism 100 is used for releasing the pole piece 500, the reeling mechanism 200 is used for reeling the pole piece 500, the first rolling mechanism 300 is arranged on a tape-passing path of the pole piece, the first rolling mechanism 300 comprises a first rolling wheel 310 and a second rolling wheel 320, the first rolling wheel 310 and the second rolling wheel 320 jointly roll the pole piece, the second rolling mechanism 400 is arranged on the tape-passing path of the pole piece, the second rolling mechanism 400 comprises a rolling component 410, the rolling component 410 comprises a third rolling wheel 411, a fourth rolling wheel 412 and a fifth rolling wheel 413, the third rolling wheel 411 and the fourth rolling wheel 412 jointly act, the third rolling wheel 411 and the fifth rolling wheel 413 jointly act, so that the blank areas of pole piece 500 are rolled, the number of rolling assemblies 410 being the same as the number of blank areas.

Specifically, as shown in fig. 1, pole piece 500 includes a coated area 510 and a blank area 520, the left-right direction shown in fig. 1 is the width direction of pole piece 500, and the width direction of pole piece 500 is perpendicular to the tape running direction of pole piece 500. Coated regions 510 and blank regions 520 alternate across the width of pole piece 500. The blank area 520 is a plurality of, and both ends all have a blank area 520 about along width direction, and the right-hand member that lies in the blank area 520 of left end portion has a coating area 510 promptly, and the left end that lies in the blank area 520 of right end portion has a coating area 510, and the left and right sides that lies in the blank area 520 of middle part all has a coating area 510.

As shown in fig. 2, the pole piece rolling device includes an unwinding mechanism 100 and a winding mechanism 200, the pole piece 500 to be stretched is disposed on the unwinding mechanism 100, the winding mechanism 200 is used for drawing the pole piece 500 to tape and wind the pole piece 500, the winding mechanism 200 is a driving roller, and when the winding mechanism 200 rotates, the pole piece 500 is wound and drives the unwinding mechanism 100 to move. The first rolling mechanism 300 is disposed on the tape path of the pole piece, i.e. between the unwinding mechanism 100 and the winding mechanism 200, as shown in fig. 2. The first rolling mechanism 300 includes a first rolling wheel 310 and a second rolling wheel 320, and the pole piece 500 released by the unwinding mechanism 100 passes through and is rolled between the first rolling wheel 310 and the second rolling wheel 320. First roller 310 and second roller 320 are the plain rolls that the metal was made, when pole piece 500 passed between first roller 310 and the second roller 320, because the thickness of the coating region 510 of pole piece is greater than the thickness of blank 520, first roller 310 and second roller 320 are used in the coating region 510 of pole piece, coating region 510 receives the roll pressure of first roller mechanism 300 and is extruded tensile, the coating material of coating region 510 is compacted, thereby can reduce the volume of pole piece, thereby improve the energy density of battery, active material in addition, the contact of conducting agent granule is inseparabler, and then improve electron conductivity. However, since the first rolling mechanism 300 acts only on the coated region 510 of the pole piece 500 and cannot roll the blank region 520 of the pole piece 500, the extension difference between the coated region 510 and the blank region 520 of the pole piece 500 is increased, and the pole piece 500 is likely to wrinkle, thereby inducing the breakage of the pole piece 500. In order to reduce the extension difference between the coating area 510 and the blank area 520, as shown in fig. 2, the pole piece rolling device further comprises a second rolling mechanism 400, and the second rolling mechanism 400 is arranged on the tape path of the pole piece 500.

As shown in fig. 3 and 4, the second rolling mechanism 400 includes a plurality of rolling assemblies 410, the plurality of rolling assemblies 410 are arranged at intervals along the width direction of the pole piece, the rolling assemblies 410 include a third rolling wheel 411, a fourth rolling wheel 412 and a fifth rolling wheel 413, the third rolling wheel 411 is arranged on one side of the pole piece (i.e. above the pole piece), the fourth rolling wheel 412 and the fifth rolling wheel 413 are arranged on the other side of the pole piece (i.e. below the pole piece), the fourth rolling wheel 412 is arranged upstream of the fifth rolling wheel 413, the rolling position between the third rolling wheel 411 and the fourth rolling wheel 412 is a first rolling position, the rolling position between the third rolling wheel 411 and the fifth rolling wheel 413 is a second rolling position, namely, the third rolling wheel 411 and the fourth rolling wheel 412 act together, and the third rolling wheel 411 and the fifth rolling wheel 413 act together, so as to roll the blank area 520 of the pole piece. During the process of passing through the rolling assembly 410, the pole piece 500 is rolled at a first rolling position and then is rolled at a second rolling position. It will be appreciated that the fourth roller 412 may also be positioned downstream of the fifth roller 413. As shown in fig. 1, a four-out coated pole piece is shown having 3 spaced apart blank regions 520 and 2 spaced apart coated regions 510 along the width of the pole piece. Second rolling mechanism 400 includes 3 rolling subassemblies 410 that the interval set up, and every rolling subassembly 410 acts on a blank region 520 for roll-in this blank region 520, under the effect of second rolling mechanism 400, roll-in blank region 520 of pole piece 500, make the blank region 520 of pole piece 500 also can the pressurized drawing. Under the combined action of first rolling mechanism 300 and second rolling mechanism 400, the coating area 510 and blank area 520 of pole piece have all received tensile, compare in only carrying out tensile mode to coating area 510, can effectually reduce the extension of coating area 510 and blank area 520 poor to reduce the emergence of the fold condition, and then can avoid the fracture of pole piece, improve the yield of pole piece. In addition, because the second rolling mechanism 400 only acts on the blank area 520 of the pole piece, the stress on the two sides of the blank area 520 can be more uniform, the rolling compaction transverse density of the blank area 520 of the pole piece is basically consistent, and the warping phenomenon after the blank area 520 is rolled can be reduced. It is understood that for one or more pole pieces, the number of rolling assemblies 410 of the second rolling mechanism 400 is set according to the number of blank areas 520 of the pole piece, so that the number of rolling assemblies 410 is the same as the number of blank areas 520 of the pole piece, and each blank area 520 of the pole piece is rolled by the rolling assembly 410. It will be appreciated that for pole piece 500 having only one side single sided void 520, the number of roller assemblies 410 is 1.

In some embodiments of the present application, a second rolling mechanism 400 is provided at least one of upstream of the first rolling mechanism 300 or downstream of the first rolling mechanism 300.

Specifically, as shown in fig. 2, a second rolling mechanism 400 is disposed between the first rolling mechanism 300 and the winding mechanism 200, that is, the second rolling mechanism 400 is disposed downstream of the first rolling mechanism 300. The unreeled pole piece 500 firstly passes through the first rolling mechanism 300, the first rolling mechanism 300 rolls the coating area 510 of the pole piece, so that the coating area 510 of the pole piece is compacted and stretched, and then the pole piece passes through the second rolling mechanism 400, so that the blank area 520 of the pole piece is stretched, and thus the coating area 510 and the blank area 520 of the pole piece are stretched. It can be understood that a second rolling mechanism 400 may be disposed between the unwinding mechanism 100 and the first rolling mechanism 300, that is, the second rolling mechanism 400 is disposed upstream of the first rolling mechanism 300, and the unwound pole piece is rolled by the second rolling mechanism 400, so that the blank area 520 of the pole piece is stretched, and then rolled by the first rolling mechanism 300, so that the coated area 510 of the pole piece is stretched. The second rolling mechanisms 400 can be arranged between the unwinding mechanism 100 and the first rolling mechanism 300 and between the first rolling mechanism 300 and the winding mechanism 200, that is, the second rolling mechanisms 400 are arranged at the upstream and the downstream of the first rolling mechanism 300, the unwound pole piece is firstly rolled by the second rolling mechanism 400, so that the blank area 520 of the pole piece is stretched, and then the pole piece is rolled by the first rolling mechanism 300, so that the coating area 510 of the pole piece is stretched, and then the pole piece is rolled by the second rolling mechanism 400 again, so that the blank area 520 of the pole piece is stretched again. By rolling the blank region 520 multiple times, the amount of stretch at each time can be reduced, thereby avoiding the risk of cracking due to a large stretch at one time.

In some embodiments of the present application, the rolling assembly 410 further comprises a driving member (not shown) connected to the third rolling wheel 411 for driving the third rolling wheel 411 to approach or separate from the fourth rolling wheel 412 and the fifth rolling wheel 413.

In particular, the drive member is a linear drive member, such as a cylinder. The third pressing roller 411 is moved closer to or away from the fourth pressing roller 412 and the fifth pressing roller 413 by the expansion and contraction of the air cylinder. When the blank area of the pole piece is to be rolled, the air cylinder drives the third rolling wheel 411 to abut against the fourth rolling wheel 412 and the fifth rolling wheel 413, and the pole piece can be pressed by the rolling assembly 410 when passing between the third rolling wheel 411 and the fifth rolling wheel 413 and between the third rolling wheel 411 and the fourth rolling wheel 412. In addition, the third rolling wheel 411 can be driven by the air cylinder to adjust the rolling pressure between the rolling wheels of the rolling assembly 410.

In some embodiments of the present application, as shown in fig. 3, a plane where an axis of the third rolling wheel 411 and an axis of the fourth rolling wheel 412 are located is a first plane, a plane where an axis of the third rolling wheel 411 and an axis of the fifth rolling wheel 413 are located is a second plane, an included angle between the first plane and the second plane is a first included angle α, the second rolling mechanism 400 further includes adjusting mechanisms 420, the number of the adjusting mechanisms 420 is the same as the number of the rolling assemblies 410, and the adjusting mechanisms 420 can adjust a position of at least one of the fourth rolling wheel 412 and the fifth rolling wheel 413 to change an angle of the first included angle α.

Specifically, as shown in fig. 3, a rolling position between the third rolling wheel 411 and the fourth rolling wheel 412 is a first rolling position, a rolling position between the third rolling wheel 411 and the fifth rolling wheel 413 is a second rolling position, and when the third rolling wheel 411 is far away from the fourth rolling wheel 412 and the fifth rolling wheel 413, a blank area of a pole piece is linearly distributed between the first rolling position and the second rolling position; when the blank area of the pole piece is to be rolled, the cylinder drives the third rolling wheel 411 to abut against the fourth rolling wheel 412 and the fifth rolling wheel 413, and the third rolling wheel 411 applies downward pressure to the blank area of the pole piece, so that the blank area of the pole piece between the first rolling position and the second rolling position is sunken downwards along the circular arc outer peripheral surface of the third rolling wheel 411 and is further stretched. The diameter of the third roller 411 is R, the plane where the axis of the third roller 411 and the axis of the fourth roller 412 are located is a first plane, the plane where the axis of the third roller 411 and the axis of the fifth roller 413 are located is a second plane, the included angle between the first plane and the second plane is a first included angle α, and the length of the stretched blank area of the pole piece is Δ L ═ R (α -2sin (α/2)). As can be seen, the second rolling mechanism 400 can quantitatively control the extension of the blank region 520, thereby eliminating the wrinkle phenomenon of the pole piece 500. According to the above formula, the stretching length of the blank area of the pole piece can be changed by adjusting the diameter of the third roller 411 and changing the angle of the first included angle α. When the extension difference between the pole piece coating area 510 and the blank area 520 is small, the pole piece can be prevented from being wrinkled or broken, so that the stretching condition of the blank area can be calculated according to the stretching requirements of different pole piece coating areas 510, and the positions of the fourth rolling wheel 412 or/and the fifth rolling wheel 413 are adjusted by arranging the adjusting mechanism 420 in the second rolling mechanism 400, so as to change the angle of the first included angle α. As shown in fig. 2 and fig. 3, the adjusting mechanism 420 may be a slider-crank structure, the fourth rolling wheel 412 is rotatably connected to the slider, and when the slider-crank mechanism moves, the fourth rolling wheel 412 is driven to move along the outer surface of the third rolling wheel 411, so as to adjust the angle of the first included angle α. The adjusting mechanism 420 may have other types of structures, and it is sufficient that the fourth pressing wheel 412 or/and the fifth pressing wheel 413 can move along the outer surface of the third pressing wheel 411. Through the arrangement mode, the first included angle alpha is adjustable, so that the pole piece rolling device meets different stretching requirements, and the application scene of the pole piece rolling device is improved. In order to avoid the pole piece from being stretched too much at one time, in some embodiments, the number of the second rolling mechanisms 400 is set to be at least 2, so that the pole piece can be stretched for multiple times, and finally, the required stretching length is achieved. Through the setting mode, the tension in the process of stretching at every time can be reduced, the stress concentration of the pole piece is reduced, and the risk of breakage of the pole piece caused by large stretching can be effectively avoided. In addition, in order to further improve the performance of the pole piece, the first included angle of the second rolling mechanism 400 is gradually increased along the tape moving path. Specifically, as shown in fig. 3, the first included angle α of the second rolling mechanism 400 located on the left side is smaller than the first included angle α of the second rolling mechanism 400 located on the right side, that is, when the pole piece passes through the second rolling mechanism 400 on the left side, the blank region 520 is stretched by a small length, and then passes through the second rolling mechanism 400 on the right side, at this time, the blank region 520 is stretched by a large length, and through the above stretching mode of small first and large second, the pole piece can be prevented from being broken due to large stretching, and the stretching efficiency of the pole piece can be effectively improved.

In some embodiments of the present application, the third roller 411 is an elastic roller. Specifically, the third roller 411 may be a rubber covered roller, and the material of the rubber covering may be a soft material such as butyl rubber or super glue, which can improve the friction between the third roller 411 and the pole piece, thereby preventing the pole piece from slipping. In addition, the third roller 411 is made of soft material and can deform during rolling, and the deformation of encapsulation can be controlled by adjusting the pressure of the third roller 411, so that the stretching length of the pole piece can be finely adjusted. The fourth roller 412 and the fifth roller 413 may also be elastic rollers. However, in order to increase the stretching effect of the pole pieces, in some embodiments, the fourth roller 412 and the fifth roller 413 are metal rollers, and the fourth roller 412 and the fifth roller 413 have rigid outer surfaces, and the rigid rollers operate to ensure that the pole pieces move at a stable speed.

In some embodiments of the present application, the second rolling mechanism 400 further comprises a pass-through rod 430, the pass-through rod 430 being disposed upstream of the rolling assembly 410. Specifically, as shown in fig. 2 and 3, the roller 430 is disposed at the right side of the first rolling mechanism 300 and at the left side of the left second rolling mechanism 400. When the pole piece passes through the roller 430, the part contacting with the roller 430 is subjected to a force vertical to the surface direction of the pole piece 600, so that the pole piece is bent and extended, the pole piece can be subjected to bending deformation treatment, the shape of the pole piece can be corrected, the tension borne by the pole piece can be reduced, and the occurrence of belt breakage is reduced.

The lithium battery production line provided by the embodiment of the second aspect of the application comprises the pole piece rolling device in the embodiment of the first aspect.

The pole piece rolling equipment in the embodiment is used in the lithium battery production line, so that 500 broken strips of the pole piece can be reduced, the product quality can be improved, and the production efficiency can be improved.

The embodiments of the present application have been described in detail with reference to the drawings, but the present application is not limited to the embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the gist of the present application. Furthermore, the embodiments and features of the embodiments of the present application may be combined with each other without conflict.

Claims

1. Pole piece roll-in device for the roll-in of pole piece, its characterized in that includes:

the unwinding mechanism is used for releasing the pole piece;

the winding mechanism is used for winding the pole piece;

2. The pole piece rolling device according to claim 1, wherein the second rolling mechanism is provided at least one of upstream of the first rolling mechanism or downstream of the first rolling mechanism.

3. The pole piece rolling device according to claim 1, wherein the rolling assembly further comprises a driving member connected to the third rolling wheel for driving the third rolling wheel to approach or separate from the fourth rolling wheel and the fifth rolling wheel.

4. The pole piece rolling device according to claim 1, wherein a plane where an axis of the third rolling wheel and an axis of the fourth rolling wheel are located is a first plane, a plane where an axis of the third rolling wheel and an axis of the fifth rolling wheel are located is a second plane, an included angle between the first plane and the second plane is a first included angle, the second rolling mechanism further comprises adjusting mechanisms, the number of the adjusting mechanisms is the same as the number of the rolling assemblies, and the adjusting mechanisms can adjust the position of at least one of the fourth rolling wheel and the fifth rolling wheel to change the angle of the first included angle.

5. The pole piece rolling device according to claim 3, wherein the number of the second rolling mechanisms is at least 2.

6. The pole piece rolling device according to claim 5, wherein in each of the second rolling mechanisms, a plane in which an axis of the third rolling wheel and an axis of the fourth rolling wheel are located is a first plane, a plane in which an axis of the third rolling wheel and an axis of the fifth rolling wheel are located is a second plane, and an included angle between the first plane and the second plane is a first included angle; along the tape transport path, the first included angle of the second rolling mechanism is gradually increased.

7. The pole piece rolling device according to claim 3, wherein the third roller is an elastic roller.

8. The pole piece rolling device of claim 7, wherein the fourth and fifth rolling wheels are both metal rolling wheels.

9. The pole piece rolling device of claim 1, wherein the second rolling mechanism further comprises a roller disposed upstream of the rolling assembly.

10. A lithium battery production line, characterized by comprising the pole piece rolling device according to any one of claims 1 to 9.