CN112296177A

CN112296177A - Pole piece forming device and pole piece forming method

Info

Publication number: CN112296177A
Application number: CN201910960331.2A
Authority: CN
Inventors: 汤克寒; 虞永生; 李世松; 邹建琨; 李克强; 廖如虎
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2019-10-10
Filing date: 2019-10-10
Publication date: 2021-02-02

Abstract

The invention provides a pole piece forming device and a pole piece forming method. The pole piece forming device comprises an unwinding mechanism, a compression roller mechanism, a stretching mechanism and a winding mechanism. Unwinding mechanism is used for setting up the pole piece, and winding mechanism is used for the rolling pole piece. The compression roller mechanism and the stretching mechanism are arranged on a tape walking path of the pole piece, and the stretching mechanism is positioned at the downstream of the compression roller mechanism. The compression roller mechanism comprises a first roller wheel and a second roller wheel, and at least one of the first roller wheel and the second roller wheel is an elastic roller. The stretching mechanism comprises a third roller and a fourth roller; the fourth rollers of the stretching mechanism are arranged in a plurality of numbers, and the fourth rollers are arranged at intervals along the axial direction parallel to the third rollers.

Description

Pole piece forming device and pole piece forming method

Technical Field

The invention relates to the field of battery production, in particular to a pole piece forming device and a pole piece forming method.

Background

At present, the requirement of each large automobile factory on the battery of the electric automobile is higher and higher, and the important point is that the energy density of the battery is higher, the battery capacity is higher under the same weight when the energy density of the battery is higher, and the mileage which can be driven by the single charging of the automobile is correspondingly increased.

In the production process of the battery pole piece, the pole piece is usually rolled to improve the compaction density of the pole piece, and further improve the energy density of the battery. Referring to fig. 1, the conventional pole piece S includes a base material S1 and a coating layer S2 disposed on the base material S1, an area of the base material S1 not coated with the coating layer S2 forms a blank area S3 of the pole piece S, an area of the base material S1 coated with the coating layer S2 and the coating layer S2 form a coated area S4 of the pole piece S. However, during the rolling process of the pole piece, the blank area S3 is not pressed and does not stretch, and the area of the substrate S1 coated with the coating S2 is subjected to rolling stretching, so that the elongation of different areas of the substrate S1 is different, the blank area S3 is easily wrinkled, and the rolling of the pole piece S is uneven.

Disclosure of Invention

In view of the problems in the background art, the present invention is directed to a pole piece forming apparatus and a pole piece forming method, which can improve the consistency of the extension of the substrate and reduce the risk of breaking the pole piece.

In order to achieve the purpose, the invention provides a pole piece forming device. The pole piece forming device comprises an unwinding mechanism, a compression roller mechanism, a stretching mechanism and a winding mechanism. Unwinding mechanism is used for setting up the pole piece, and winding mechanism is used for the rolling pole piece. The compression roller mechanism and the stretching mechanism are arranged on a tape walking path of the pole piece, and the stretching mechanism is positioned at the downstream of the compression roller mechanism. The compression roller mechanism comprises a first roller wheel and a second roller wheel, and at least one of the first roller wheel and the second roller wheel is an elastic roller. The stretching mechanism comprises a third roller and a fourth roller; the fourth rollers of the stretching mechanism are arranged in a plurality of numbers, and the fourth rollers are arranged at intervals along the axial direction parallel to the third rollers.

The drawing mechanisms are multiple and are sequentially arranged along the tape running direction of the pole piece.

The pole piece forming device further comprises an adjusting roller and a first driving unit, the adjusting roller is arranged on a tape walking path of the pole piece and located between the adjacent stretching mechanisms, and the first driving unit is connected to the adjusting roller.

The third roller is a driving roller.

The fourth roller comprises a roller body and an elastic layer coated on the roller body. The third roller is a metal roller.

The stretching mechanism further comprises a plurality of second driving units and a guiding unit, and the plurality of second driving units are slidably arranged on the guiding unit. Each second driving unit is connected to a corresponding fourth roller and can drive the fourth roller to be close to or far away from the third roller.

The second drive unit comprises a support frame, a mounting frame, a first guide rail and a cylinder, the support frame is connected to the guide unit, the first guide rail and the cylinder are fixed on the support frame, the mounting frame is connected to the cylinder and the first guide rail, and the fourth roller is rotatably connected to the mounting frame.

The guide unit includes a guide shaft and a second guide rail. The second drive unit further comprises a fixed seat, a sliding block and a locking piece, the fixed seat and the sliding block are fixed on the support frame, the sliding block is connected to the second guide rail in a sliding mode, the fixed seat is connected to the guide shaft in a sliding mode, and the locking piece is connected to the fixed seat.

The pole piece forming device further comprises a roller mechanism, the roller mechanism is arranged on a tape travelling path of the pole piece, and the roller mechanism is positioned at the upstream of the pressing roller mechanism or the downstream of the stretching mechanism. The roller mechanism comprises a fifth roller and a sixth roller.

The stretching mechanism further comprises a transmission shaft, and the plurality of fourth rollers are sleeved on the transmission shaft and are rotatably connected to the transmission shaft.

In order to achieve the purpose, the invention also provides a pole piece forming method. The pole piece forming method comprises the following steps: arranging the pole piece with the blank area and the coating area on an unwinding mechanism; the traction pole piece passes through the space between the first roller and the second roller, then the traction pole piece passes through the space between the third roller and the fourth roller, and the pole piece is connected to the winding mechanism; pressing the first roller and the second roller to the blank area and the coating area of the pole piece, and pressing the third roller and the fourth roller to the blank area of the pole piece; the winding mechanism winds the pole piece to drive the pole piece to move, the first roller and the third roller rotate, and the linear speed of the first roller is smaller than that of the third roller.

The step of leading the pole piece to pass through the space between the third roller wheel and the fourth roller wheel comprises the following steps: the traction pole piece passes through between one third roller and one fourth roller, and then the traction pole piece passes through between the other third roller and the other fourth roller. When the winding mechanism winds the pole piece, the linear speed of one third roller is smaller than that of the other third roller.

The pole piece forming method further comprises the following steps: the traction pole piece passes through the space between the fifth roller and the sixth roller, and the pole piece firstly passes through the space between the fifth roller and the sixth roller and then passes through the space between the first roller and the second roller.

The invention has the following beneficial effects: this application can utilize the blank area of the tensile pole piece of speed difference, reduces the risk that blank area crumpled. Meanwhile, the first roller and the second roller can press the blank area and the coating area, so that the mutual influence of the tension of the pole piece positioned at the upstream of the compression roller mechanism and the tension of the pole piece positioned at the downstream of the compression roller mechanism can be eliminated, and the risk of breakage of the pole piece in the differential stretching process is reduced.

Drawings

FIG. 1 is a schematic view of a pole piece.

Fig. 2 is a schematic view of a pole piece forming device according to the present invention.

Fig. 3 is a schematic view of an embodiment of a stretching mechanism of the pole piece forming device according to the present invention.

FIG. 4 is a schematic representation of a pole piece during stretching.

Fig. 5 is a schematic view of a stretching mechanism of the pole piece forming device according to the present invention.

Fig. 6 is a schematic view of a fourth roller of the stretching mechanism of the pole piece forming device according to the invention.

Fig. 7 is a schematic view of another embodiment of the stretching mechanism of the pole piece forming device according to the invention.

Wherein the reference numerals are as follows:

1 unwinding mechanism 341 guide shaft

2 second guide rail of press roller mechanism 342

21 first roller 35 drive shaft

22 second roller 36 frame

3 stretching mechanism 37 motor

31 third roller 4 winding mechanism

32 fourth roller 5 regulating roller

321 roller body 6 first drive unit

322 elastic layer 7 roller mechanism

33 second drive unit 71 fifth roll

331 supporting frame 72 sixth roller

332 mounting frame S pole piece

333 first guide S1 base material

334 cylinder S2 coating

335 permanent seat S3 blank area

336 slider S4 coating area

337 locking member X transverse direction

34 guide unit

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further 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 present application and are not intended to limit the present application.

In the description of the present application, unless explicitly stated or limited otherwise, the terms "first", "second", "third", and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance; the term "plurality" means more than two (including two); the term "coupled", unless otherwise specified or indicated, is to be construed broadly, e.g., "coupled" may be a fixed or removable connection or a connection that is either integral or electrical or signal; "connected" may be directly connected or indirectly connected through an intermediate. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

In the description of the present application, it should be understood that the terms "upper" and "lower" used in the description of the embodiments of the present application are used in a descriptive sense only and not for purposes of limitation. The present application is described in further detail below with reference to specific embodiments and with reference to the attached drawings.

The pole piece forming device can be used for producing the pole piece S of the battery. Specifically, referring to fig. 1, the pole piece S includes a substrate S1 and a coating S2, the substrate S1 may be a metal foil, and the coating S2 may include an active material. When the pole piece S is a negative pole piece, the active substance comprises graphite or silicon; when the pole piece S is a positive pole piece, the active material comprises a ternary material, lithium manganate or lithium iron phosphate.

The substrate S1 includes a first region uncoated with the coating S2 and a second region coated with the coating S2, the first region of the substrate S1 forming a blank region S3 of the pole piece S, and the second regions of the coating S2 and the substrate S1 forming a coated region S4 of the pole piece S. Referring to fig. 1, the blank regions S3 and the coated regions S4 are alternately arranged in the width direction of the pole piece S.

In the production process of the pole piece S, the pole piece S is usually wound into a roll. The transverse direction X described later is parallel to the width direction of the pole piece S, and the upstream and downstream described later are both in terms of the running direction of the pole piece S.

In the production process of the pole piece S, the pole piece S is usually rolled to thin the coating S2, increase the density of the coating S2, and further increase the energy density of the pole piece S. However, during the rolling of the pole piece S, the coating area S4 is acted by the rolling force, so the second area of the substrate S1 will extend under the rolling force, and the blank area S3 is not acted by the rolling force, so the first area of the substrate S1 will hardly extend, which results in different extensibility of different areas of the substrate S1, the blank area S3 of the pole piece S is prone to wrinkle, and the rolling of the pole piece S will be uneven.

The pole piece forming device can be used for stretching the blank area S3 of the pole piece S. Specifically, referring to fig. 2, the pole piece forming device of the present application includes an unwinding mechanism 1, a pressing roller mechanism 2, a stretching mechanism 3, and a winding mechanism 4.

Specifically, the unwinding mechanism 1 may include an unwinding roller, and when the blank area S3 of the pole piece S needs to be stretched, the roll of the pole piece S may be set on the unwinding roller. And the winding mechanism 4 is used for drawing the pole piece S to move and winding the pole piece S. The winding mechanism 4 may include a winding roller, which is a driving roller.

The compression roller mechanism 2 and the stretching mechanism 3 are arranged on a tape path of the pole piece S, and the stretching mechanism 3 is positioned at the downstream of the compression roller mechanism 2.

The press roller mechanism 2 includes a first roller 21 and a second roller 22, and at least one of the first roller 21 and the second roller 22 is an elastic roller. Preferably, the first roller 21 is a metal roller, such as a steel roller. The second roller 22 is an elastic roller, which means that a roller surface thereof can be elastically deformed at the time of rolling. In one embodiment, the second roller 22 may be a rubber roller as a whole; in another embodiment, the second roller 22 includes a roller body and an elastic layer covering the roller body, and the roller body may be a metal core shaft. The elastic layer can be made of nitrile rubber or acrylic rubber. The first roller 21 and the second roller 22 may be flat rollers.

The stretching mechanism 3 includes a third roller 31 and a fourth roller 32. The fourth rollers 32 of the stretching mechanism 3 are provided in plurality, and the plurality of fourth rollers 32 are provided at intervals in a direction parallel to the axial direction of the third roller 31. The third roller 31 and the fourth roller 32 are both flat rollers. Referring to fig. 3, the third roller 31 has a size larger than that of the fourth roller 32 in a direction parallel to the axial direction of the third roller 31 (i.e., the lateral direction X in the drawing).

The working process of the pole piece forming device of the application is briefly described below.

When the blank area S3 of the pole piece S needs to be stretched, the coil stock of the pole piece S is firstly arranged on the unwinding mechanism 1, and then the pole piece S is pulled to move. Specifically, the pole piece S is drawn between the first roller 21 and the second roller 22, then drawn between the third roller 31 and the fourth roller 32, and connected to the winding mechanism 4.

Then, the first roller 21 and the second roller 22 are driven to move relatively, so that the first roller 21 and the second roller 22 are pressed against the blank area S3 and the coating area S4 of the pole piece S. At least one of the first roller 21 and the second roller 22 is an elastic roller, and the elastic roller can be pressed against the blank area S3 by elastic deformation.

The third roller 31 and the fourth roller 32 are driven to move relatively, so that the third roller 31 and the fourth roller 32 are pressed against the blank area S3 of the pole piece S. The number of the fourth rollers 32 is plural, and each fourth roller 32 presses a corresponding blank area S3.

The winding mechanism 4 winds the pole piece S by rotating, and then drives the pole piece S to move. When the pole piece S is transported, the first roller 21 and the third roller 31 are driven to rotate by the power equipment, and the linear velocity of the first roller 21 is smaller than that of the third roller 31.

Referring to fig. 4, during the running of the pole piece S, the blank area S3 of the pole piece S is in close contact with the roller surface of the first roller 21 without slipping, so the running speed V of the blank area S3 of the pole piece S is set between the first roller 21 and the second roller 22₁Is the linear velocity of the first roller 21. In the process of the traveling of the pole piece S, the blank area S3 of the pole piece S is in close contact with the roller surface of the third roller 31 without slipping, so the traveling speed V of the blank area S3 of the pole piece S is between the third roller 31 and the fourth roller 32₂The linear velocity of the third roller 31. Due to V₂Greater than V₁Therefore, the blank space S3 is subjected to tangential tension and thus stretched.

Since the third roller 31 and the fourth roller 32 do not press the coating zone S4, the third roller 31 has a small influence on the traveling speed of the coating zone S4.

In addition, the first roller 21 and the second roller 22 can press the blank area S3 and the coating area S4, so that the mutual influence between the tension of the pole piece S located upstream of the pressing roller mechanism 2 and the tension of the pole piece S located downstream of the pressing roller mechanism 2 can be eliminated, and the risk of breaking the pole piece S during differential stretching can be reduced.

Referring to fig. 2 and 4, the drawing mechanism 3 is plural, and the plural drawing mechanisms 3 are sequentially arranged along the tape running direction of the pole piece S.

In some embodiments, there may be two stretching mechanisms 3. The pole piece S passes through between the third roller 31 and the fourth roller 32 of one upstream stretching mechanism 3, and then passes through between the third roller 31 and the fourth roller 32 of the other downstream stretching mechanism 3. Referring to FIG. 4, the tape running speed V of the blank space S3 when passing through the upstream stretching mechanism 3₂The linear velocity of the third roller 31 of the stretching mechanism 3; the tape running speed V of the blank space S3 while passing through the downstream stretching mechanism 3₃The linear velocity of the third roller 31 of the stretching mechanism 3. Due to V₃>V₂The blank space S3 is subjected to tangential tension, so that the blank space S3 is further stretched between the two stretching mechanisms 3.

The elongation of the blank region S3 is determined by the velocity difference (e.g., V)₃-V₁) Therefore, the pole piece forming device can ensure that the blank area S3 extends at a constant elongation; when the blank region S3 reaches the target elongation, the blank region S3 is not subjected to the continuous action of the tangential tension, and therefore, even if the blank region S3 is defective during the elongation process, the blank region is not excessively deteriorated, thereby reducing the risk of ribbon breakage.

The plurality of stretching mechanisms 3 can divide the stretching process of the blank area S3 into multiple stages, reduce tension in each stretching process, avoid stress concentration, and reduce the risk of breaking of the blank area S3.

Referring to fig. 2, the pole piece forming device further includes an adjusting roller 5 and a first driving unit 6, the adjusting roller 5 is disposed on a tape path of the pole piece S, and the first driving unit 6 is connected to the adjusting roller 5. The dancer 5 is located between adjacent stretching mechanisms 3 in the direction of travel of the pole piece S. The first driving unit 6 may include an air cylinder, and the air cylinder may drive the adjusting roller 5 to reciprocate. By changing the position of the adjusting roller 5, the wrap angle of the pole piece S on the third roller 31 of the stretching mechanism 3 can be adjusted, so that the pole piece S enters the stretching mechanism 3 with a set friction force, uneven tension on the pole piece S is reduced, and the risk of belt breakage is reduced. When the model of the pole piece S is changed, the first driving unit 6 may adjust the position of the dancer roller 5 to accommodate the change in the pole piece S.

In the production process of the battery pole piece S, in order to improve the production efficiency, a plurality of coating layers S2 are usually coated on the base material S1. Referring to fig. 1, the base material S1 has a plurality of blank spaces S3. Of course, the fourth roller 32 of the drawing mechanism 3 is also provided in plural for simultaneously drawing the blank space S3. Preferably, the fourth rollers 32 may have a larger number, for example 5-7. Thus, when the number of blank spaces S3 of the pole piece S is changed, only the number of fourth rollers 32 that are active needs to be changed.

In addition, when the width of the coating S2 of the pole piece S is changed, the requirement of the pole piece S can be satisfied by changing the distance between the adjacent fourth rollers 32.

The third roller 31 is a driving roller, and the fourth roller 32 is a driven roller. The stretching mechanism 3 further comprises a motor 37, and the motor 37 is connected to the third roller 31 and drives the third roller 31 to rotate. In the present application, the third roller 31 is a driving roller, so the tape running speed of the blank areas S3 of the pole piece S is equal to the linear speed of the third roller 31, thereby ensuring the consistency of the tape running speed of the blank areas S3 and reducing the risk of crumpling the blank areas S3. The motor 37 is preferably a high-precision motor, the rotation control precision of the motor reaches 0.1%, and the speed ratio control precision range is below 0.2%.

The third roller 31 is a metal roller, for example, the third roller 31 is a solid steel roller. The metal roller has high precision and abrasion resistance, can accurately convert the angular velocity into the linear velocity, namely accurately control the tape running speed of the blank area S3 and ensure the consistency of the tape running speeds of the blank areas S3.

Referring to fig. 6, the fourth roller 32 includes a roller body 321 and an elastic layer 322 coated on the roller body 321. The elastic layer 322 is easily soft and easily elastically deformable. Because the pole piece S is thin (the pole piece S is generally 100 μm to 200 μm, the base material S1 is generally 6 μm to 20 μm), the pressure required for the pole piece S to deform plastically is greater than the force required for the elastic layer 322 to deform elastically, so that the roller pressure exerted by the third roller 31 and the fourth roller 32 on the blank area S3 is not enough to thin the blank area S3, and only the blank area S3 and the third roller 31 can be ensured to be in close contact without relative sliding. In summary, in the present application, the blank space S3 is extended by the speed difference of the blank space S3 between the press roller mechanism 2 and the stretching mechanism 3, rather than the roller pressure between the third roller 31 and the fourth roller 32. The roller body 321 may be a metal core shaft, and the elastic layer 322 may be made of nitrile rubber or acrylic rubber.

Referring to fig. 2, the pole piece forming device of the present application further includes a roller mechanism 7, the roller mechanism 7 is disposed on the tape path of the pole piece S, and the roller mechanism 7 is located upstream of the roller mechanism 2 or downstream of the stretching mechanism 3. The roll mechanism 7 includes a fifth roll 71 and a sixth roll 72, and the pole piece S passes through between the fifth roll 71 and the sixth roll 72 and is rolled. The fifth roller 71 and the sixth roller 72 are both flat rollers made of metal.

The fifth roller 71 may be connected to the air cylinder to be moved closer to or away from the sixth roller 72 by the air cylinder. By controlling the interval between the fifth roller 71 and the sixth roller 72, the roller pressure between the fifth roller 71 and the sixth roller 72 can be changed, and the thickness of the coating zone S4 can be adjusted. The sixth roller 72 can be connected to a motor, and the motor drives the sixth roller 72 to rotate, so as to drive the pole piece S to move.

When the pole piece S passes between the fifth roller 71 and the sixth roller 72, the coating region S4 is compressed by force, thereby increasing the density of the coating S2. At the same time, the second region of the substrate S1 is also extended by the roller pressure.

In the present application, the fifth roller 71 and the sixth roller 72 can roll the second region of the base material S1, and the stretching mechanism 3 stretches the first region of the base material S1 by using the speed difference, so the present application integrates the rolling process of the rolling mechanism 7 and the stretching process of the stretching mechanism 3, and makes the elongation of the whole base material S1 consistent or close, thereby preventing the blank region S3 of the base material S1 from being wrinkled or tilted.

In some embodiments, the roller mechanism 7 is located upstream of the roller mechanism 2. When the pole piece S is drawn to pass through the belt, the pole piece S firstly passes through the space between the fifth roller 71 and the sixth roller 72, and then passes through the space between the first roller 21 and the second roller 22.

Referring to fig. 3 and 5, the stretching mechanism 3 further includes a plurality of second driving units 33 and a guide unit 34, the plurality of second driving units 33 being slidably provided to the guide unit 34. Each of the second driving units 33 is connected to a corresponding one of the fourth rollers 32 and is capable of driving the fourth roller 32 closer to or farther from the third roller 31. Each second driving unit 33 can adjust the distance between the corresponding fourth roller 32 and the corresponding third roller 31, that is, the roller pressure between each fourth roller 32 and the corresponding third roller 31 can be precisely controlled, so as to ensure the uniformity of the stress on the plurality of blank areas S3 of the pole piece S.

When the width of the coating S2 of the pole piece S is changed, the second driving unit 33 may be slid along the guide unit 34 to adjust the spacing between adjacent fourth rollers 32 to accommodate the change in the size of the pole piece S.

The second driving unit 33 includes a supporting frame 331, a mounting frame 332, a first rail 333, and a cylinder 334, the supporting frame 331 is coupled to the guide unit 34, the first rail 333 and the cylinder 334 are fixed to the supporting frame 331, the mounting frame 332 is coupled to the cylinder 334 and the first rail 333, and the fourth roller 32 is rotatably coupled to the mounting frame 332. The first rail 333 is a linear rail. The cylinder 334 can move the fourth roller 32 close to or away from the third roller 31 through the mounting frame 332 and the first guide rail 333. When the width of the coating S2 of the pole piece S is changed, the support frame 331 can be manually pushed, so as to adjust the spacing between the fourth rollers 32 of the stretching mechanism 3.

The guide unit 34 includes a guide shaft 341 and a second guide rail 342. The guide shaft 341 and the second guide rail 342 may be mounted to the frame 36. The second driving unit 33 further includes a fixing base 335, a sliding block 336 and a locking member 337, wherein the fixing base 335 and the sliding block 336 are fixed on the supporting frame 331, the sliding block 336 is slidably connected to the second guiding rail 342, and the fixing base 335 is slidably connected to the guiding shaft 341. The locking member 337 is connected to the fixing seat 335 and can fix the fixing seat 335 to the guide shaft 341.

The retaining member 337 can include a bolt threadedly coupled to the holder 335 and a handle coupled to the bolt. By rotating the handle, the bolt can be loosened or tightened.

When the bolt is loosened, the fixing seat 335 can loosen the guide shaft 341, and the fixing seat 335 can slide along the guide shaft 341. At this time, the supporting frame 331 may be manually pushed, thereby adjusting the spacing between the plurality of fourth rollers 32 of the stretching mechanism 3. When the fourth roller 32 of the stretching mechanism 3 moves to the target position, the bolt is tightened, and the fixing seat 335 can clamp the guide shaft 341 to prevent the fixing seat 335 from sliding along the guide shaft 341.

In some embodiments, the fourth rollers 32 of the stretching mechanism 3 may also be integrated. Referring to fig. 7, the stretching mechanism 3 further includes a transmission shaft 35, and the plurality of fourth rollers 32 are sleeved on the transmission shaft 35 and rotatably connected to the transmission shaft 35. Each fourth roller 32 has an annular shape. At this time, one transmission shaft 35 can simultaneously drive the plurality of fourth rollers 32 to approach or separate from the third roller 31, thereby simplifying the structure of the stretching mechanism 3.

The fourth roller 32 is a driven roller, and is driven to rotate by the blank space S3. The resilient layer 322 of the fourth roller 32 wears over time, resulting in a different outer diameter of the fourth roller 32 in different areas. If all of the fourth rollers 32 are fixed to the transmission shaft 35, a difference occurs in the linear velocity of the plurality of fourth rollers 32 at the same angular velocity, causing some of the fourth rollers 32 to slip with respect to the blank space S3. In the present application, the plurality of fourth rollers 32 are rotatably connected to the transmission shaft 35, and the angular velocities of the plurality of fourth rollers 32 are independent from each other, so that even if the elastic layer 322 of the fourth rollers 32 is worn, the linear velocities of the plurality of fourth rollers 32 can be ensured to be consistent, and the fourth rollers 32 are prevented from sliding relative to the blank space S3.

The application also discloses a pole piece forming method, and the method can improve the extending consistency of the base material and avoid the base material from being wrinkled.

Specifically, referring to fig. 1 to 4, the pole piece forming method of the present application includes:

setting a pole piece S having a blank area S3 and a coating area S4 to an unwinding mechanism 1;

the traction pole piece S passes through the space between the first roller 21 and the second roller 22, then the traction pole piece S passes through the space between the third roller 31 and the fourth roller 32, and the traction pole piece S is connected to the winding mechanism 4;

pressing the first roller 21 and the second roller 22 against the blank area S3 and the coating area S4 of the pole piece S, and pressing the third roller 31 and the fourth roller 32 against the blank area S3 of the pole piece S;

the winding mechanism 4 winds the pole piece S to drive the pole piece S to move, and rotates the first roller 21 and the third roller 31, wherein the linear velocity of the first roller 21 is less than that of the third roller 31.

The pole piece forming method can stretch the blank area S3 of the pole piece S by using the speed difference, and reduces the risk of wrinkling of the blank area S3. Meanwhile, the first roller 21 and the second roller 22 can press the blank area S3 and the coating area S4, so that the mutual influence between the tension of the pole piece S located upstream of the first roller 21 and the tension of the pole piece S located downstream of the first roller 21 can be eliminated, and the risk of breaking the pole piece S in the differential stretching process can be reduced.

The step of drawing the pole piece S to pass through the third roller 31 and the fourth roller 32 includes: the traction pole piece S passes between one third roller 31 and one fourth roller 32, and then the traction pole piece S passes between the other third roller 31 and the other fourth roller 32. When the winding mechanism 4 winds the pole piece S, the linear velocity of the one third roller 31 is smaller than the linear velocity of the other third roller 31.

In the pole piece forming method, the drawing process of the blank area S3 can be divided into multiple stages, so that the tension in the drawing process at each time is reduced, stress concentration is avoided, and the risk of breakage of the blank area S3 is reduced.

The method further comprises the following steps: the pole piece S is drawn to pass through between the fifth roller 71 and the sixth roller 72, and the pole piece S passes through between the fifth roller 71 and the sixth roller 72 and then passes through between the first roller 21 and the second roller 22.

In the pole piece forming method of the application, the fifth roller 71 and the sixth roller 72 can press the coating S2 of the pole piece S to be thin, so that the energy density of the pole piece S is improved. In addition, the fifth roller 71 and the sixth roller 72 can roll the second area of the base material S1, and the third roller 31 and the fourth roller 32 stretch the first area of the base material S1 by using the speed difference, so that the rolling process of the pole piece S and the stretching process of the blank area S3 are integrated together, the elongation of the whole base material S1 is consistent or close, and the blank area S3 of the base material S1 is prevented from being wrinkled or tilted.

Claims

1. A pole piece forming device is characterized by comprising an unreeling mechanism (1), a press roller mechanism (2), a stretching mechanism (3) and a reeling mechanism (4);

the unwinding mechanism (1) is used for arranging the pole piece (S), and the winding mechanism (4) is used for winding the pole piece (S);

the compression roller mechanism (2) and the stretching mechanism (3) are arranged on a tape walking path of the pole piece (S), and the stretching mechanism (3) is positioned at the downstream of the compression roller mechanism (2);

the press roll mechanism (2) comprises a first roller (21) and a second roller (22), and at least one of the first roller (21) and the second roller (22) is an elastic roll;

the stretching mechanism (3) comprises a third roller (31) and a fourth roller (32); the number of the fourth rollers (32) of the stretching mechanism (3) is multiple, and the fourth rollers (32) are arranged at intervals along the direction parallel to the axial direction of the third roller (31).

2. The pole piece forming device according to claim 1, wherein the drawing mechanism (3) is a plurality of drawing mechanisms, and the drawing mechanisms (3) are arranged in sequence along the tape running direction of the pole piece (S).

3. The pole piece forming device according to claim 2, characterized in that it further comprises a regulating roller (5) and a first driving unit (6), the regulating roller (5) being arranged in the path of the pole piece (S) and between adjacent stretching mechanisms (3), the first driving unit (6) being connected to the regulating roller (5).

4. The pole piece forming device according to claim 1, wherein the third roller (31) is a drive roller.

5. The pole piece forming device of claim 1,

the fourth roller (32) comprises a roller body (321) and an elastic layer (322) coated on the roller body (321);

the third roller (31) is a metal roller.

6. The pole piece forming device of claim 1,

the stretching mechanism (3) further comprises a plurality of second driving units (33) and a guide unit (34), wherein the plurality of second driving units (33) are slidably arranged on the guide unit (34);

each second driving unit (33) is connected to a corresponding one of the fourth rollers (32) and can drive the fourth roller (32) to approach or separate from the third roller (31).

7. The pole piece forming device according to claim 6, wherein the second driving unit (33) comprises a support frame (331), a mounting frame (332), a first guide rail (333) and a cylinder (334), the support frame (331) is connected to the guiding unit (34), the first guide rail (333) and the cylinder (334) are fixed on the support frame (331), the mounting frame (332) is connected to the cylinder (334) and the first guide rail (333), and the fourth roller (32) is rotatably connected to the mounting frame (332).

8. The pole piece forming device of claim 7,

the guide unit (34) includes a guide shaft (341) and a second guide rail (342);

the second driving unit (33) further comprises a fixed seat (335), a sliding block (336) and a locking piece (337), the fixed seat (335) and the sliding block (336) are fixed on the supporting frame (331), the sliding block (336) is connected to the second guide rail (342) in a sliding manner, the fixed seat (335) is connected to the guide shaft (341) in a sliding manner, and the locking piece (337) is connected to the fixed seat (335).

9. The pole piece forming device of claim 1,

the pole piece forming device further comprises a roller mechanism (7), the roller mechanism (7) is arranged on a tape moving path of the pole piece (S), and the roller mechanism (7) is positioned at the upstream of the compression roller mechanism (2) or the downstream of the stretching mechanism (3);

the roller mechanism (7) comprises a fifth roller (71) and a sixth roller (72).

10. The pole piece forming device according to claim 1, wherein the stretching mechanism (3) further comprises a transmission shaft (35), and the fourth rollers (32) are sleeved on the transmission shaft (35) and rotatably connected to the transmission shaft (35).

11. A pole piece forming method is characterized by comprising the following steps:

setting a pole piece (S) having a blank region (S3) and a coated region (S4) to an unwinding mechanism (1);

the traction pole piece (S) passes through the space between the first roller (21) and the second roller (22), then the traction pole piece (S) passes through the space between the third roller (31) and the fourth roller (32), and the traction pole piece (S) is connected to the winding mechanism (4);

pressing the first roller (21) and the second roller (22) against the blank area (S3) and the coating area (S4) of the pole piece (S), and pressing the third roller (31) and the fourth roller (32) against the blank area (S3) of the pole piece (S);

the winding mechanism (4) winds the pole piece (S) to drive the pole piece (S) to move, the first roller (21) and the third roller (31) are made to rotate, and the linear speed of the first roller (21) is smaller than that of the third roller (31).

12. The pole piece molding method according to claim 11,

the traction pole piece (S) passes through the space between the third roller (31) and the fourth roller (32) and comprises the following steps: the traction pole piece (S) passes through between one third roller (31) and one fourth roller (32), and then the traction pole piece (S) passes through between the other third roller (31) and the other fourth roller (32);

when the winding mechanism (4) winds the pole piece (S), the linear speed of one third roller (31) is smaller than that of the other third roller (31).

13. The pole piece molding method according to claim 11,

the pole piece forming method further comprises the following steps: the traction pole piece (S) passes through the space between the fifth roller (71) and the sixth roller (72), and the pole piece (S) firstly passes through the space between the fifth roller (71) and the sixth roller (72) and then passes through the space between the first roller (21) and the second roller (22).