Roller press and stretching and rolling method for lithium ion battery pole piece

Abstract

The invention discloses a roller press and a stretching and rolling method for a lithium ion battery pole piece. The roller press comprises an unwinding mechanism, a first clamping and stretching mechanism, a roller mechanism, a second clamping and stretching mechanism and a winding mechanism which are arranged in sequence, the roller mechanism comprises an upper roller and a lower roller, the distance and the rolling pressure of the upper roller and the lower roller are adjustable, the upper roller is a straight roller, and the lower roller is a radian roller; roller bosses with a heating function are arranged on the surfaces of the upper roller and the lower roller; and pinch roll bosses are arranged on the surfaces of the pinch rolls in the first pinch stretching mechanism and the second pinch stretching mechanism. According to the invention, the phenomenon that the edge of a pole piece is overpressed due to deflection can be relieved through the lower roller with the cambered surface, so that the thickness consistency of rolling is improved, a good stretching effect on a pole lug can be achieved through the pinch roller boss and the roller boss, and the heating device on the roller boss is used for heating the roller boss, so that the quality of the pole piece is improved. Therefore, the tab is heated and softened and is easier to stretch.

Description

Technical Field

[0001] The invention belongs to the field of lithium ion battery manufacturing, and in particular relates to a roller press and a stretching and rolling method for lithium ion battery pole pieces. Background Art

[0002] In recent years, lithium-ion batteries have been widely used not only in portable electronic devices such as mobile phones, digital cameras and laptops, but also in large electric equipment such as electric vehicles, electric bicycles and power tools due to their advantages such as high voltage, high specific energy, many cycles and long storage time. Therefore, the safety requirements for lithium-ion batteries are becoming increasingly higher.

[0003] In the production process of lithium-ion batteries, it is necessary to Figure 2 The material in the dressing area is stretched after rolling, but the tab blank area is not stretched and stretched, so the tab blank area and the dressing area are stretched out of sync, resulting in serious wrinkling and breaking of the tab blank area. In addition, because the rollers of the roller press are deflected under stress, the gap between the upper and lower rollers is smaller than the gap in the middle area, so the edge position is more stressed, and edge overpressure is prone to occur.

[0004] In order to solve the problem of asynchronous stretching of the tabs, the industry currently usually adopts roller tension roller clamping stretching and Teflon tape to force synchronous stretching of the blank area of ​​the tabs. However, this conventional method has the problem of uneven skill levels of operators in sticking Teflon, and the Teflon tape is easy to wear, which is not conducive to process control. In addition, there is also a method of using electromagnetic heating (IHA) to heat the tab area to release the stress in the tab area. However, electromagnetic heating is non-contact heating and cannot achieve significant improvement at a faster speed. For the edge overpressure phenomenon, the current conventional practice in the industry is to alleviate the overpressure phenomenon on both sides through a roller bending cylinder, but this method has extremely limited improvement on the edge overpressure. In summary, poor tab stretching and edge overpressure will aggravate roller belt breakage. Summary of the invention

[0005] In view of the defects of the above-mentioned prior art, the present invention provides a roller press and a stretching and rolling method for lithium-ion battery pole pieces, so as to improve the stretching synchronization between the blank area of ​​the pole tab and the dressing area, and at the same time improve the consistency of the rolling thickness.

[0006] In order to solve the above technical problems and achieve the above technical effects, the present invention is implemented through the following technical solutions: A roller press for lithium-ion battery pole pieces, comprising an unwinding mechanism, a first clamping and stretching mechanism, a rolling mechanism, a second clamping and stretching mechanism and a winding mechanism which are arranged in sequence; The roller mechanism includes an upper roller and a lower roller with adjustable upper and lower spacing and rolling pressure. The upper roller is a straight roller that is flat as a whole, and the lower roller is a curved roller with a certain curvature on the surface. The first pinching and stretching mechanism and the second pinching and stretching mechanism both include a number of corresponding pinching rollers.

[0007] Furthermore, the curvature of the lower rolling roller is Π / 2~Π.

[0008] Furthermore, the pressurizing method of the roller mechanism is that the upper roller remains fixed and the lower roller is lifted and pressurized by a hydraulic cylinder.

[0009] Furthermore, the surfaces of the upper roller and the lower roller are circumferentially provided with 2 to 8 roller bosses with heating function, the number and distribution positions of the roller bosses on the upper roller and the roller bosses on the lower roller correspond to the number and distribution positions of the blank areas of the pole lugs on the lithium-ion battery pole pieces to be rolled, and the height of each roller boss is 5 to 50 um and the width is 5 to 60 mm.

[0010] Furthermore, the roller bosses are processed by electroplating technology, and the distribution positions of the roller bosses correspond to the distribution positions of the tab blank areas of the lithium-ion battery pole pieces after coating; and the widths of the roller bosses at different positions are slightly smaller than the widths of the corresponding tab blank areas, and the spacing between two adjacent roller bosses is slightly larger than the width of the corresponding dressing areas; usually the width of the tab blank area is 5~100 mm, and the width of the dressing area is 200~1000 mm.

[0011] Furthermore, there is a gap of 0.5-1.5 mm between the edge of the roller boss and the edge of the adjacent dressing area.

[0012] Furthermore, the upper roller and the lower roller corresponding to each roller boss position are provided with a circulating heat transfer oil circuit for heating the corresponding roller boss, and the circulating heat transfer oil circuit is injected with circulating heat transfer oil that can perform high-temperature heating, and the circulating heat transfer oil can withstand a heating temperature of 50~200℃.

[0013] Furthermore, the surface of the pinching roller located in the first pinching and stretching mechanism and the surface of the pinching roller located in the second pinching and stretching mechanism are both provided with 2 to 8 pinching roller bosses, and the number and distribution positions of the pinching roller bosses located on the surface of the pinching roller in the first pinching and stretching mechanism and the pinching roller bosses located on the surface of the pinching roller in the second pinching and stretching mechanism correspond to the number and distribution positions of the blank areas of the pole ears on the lithium-ion battery pole piece to be rolled, and the height of each pinching roller boss is 30 to 300 um and the width is 5 to 60 mm.

[0014] A method for stretching and rolling a lithium-ion battery pole piece using the above-mentioned roller press, the steps of which include: Step 1) according to the overall size of the lithium-ion battery pole piece and the distribution position of the dressing area and the blank area of ​​the pole tab after coating, select the appropriate upper roller and the lower roller, and correctly install them on the roller mechanism; Step 2) opening the circulating heat transfer oil circuit disposed inside the upper roll and the lower roll in advance to heat the roll bosses disposed on the upper roll and the lower roll; Step 3) setting the roller gap between the upper roller and the lower roller, setting the rolling pressure of the upper roller and the lower roller, and setting the rolling speed of the upper roller and the lower roller; Step 4) The coated lithium-ion battery electrode sheet is led out from the unwinding mechanism, and is sequentially passed through the first clamping and stretching mechanism, the rolling mechanism, and the second clamping and stretching mechanism before being wound on the winding mechanism; Step 5) Start the roller press to start pulling, and stop the machine after the lithium-ion battery pole piece is corrected and straightened. At this time, there is a certain gap between the edge of the roller boss and the edge of the adjacent auxiliary material area. After the rolling pressure is increased, start the roller press again to start pulling, so as to formally stretch and roll the lithium-ion battery pole piece; Step 6) During the rolling process, the roller boss stretches the blank area of ​​the pole lug, and the heating of the roller boss by the circulating heat transfer oil circuit causes the blank area of ​​the pole lug to soften due to the heat, thereby promoting stretching; at the same time, the pinch roller boss further stretches the blank area of ​​the pole lug; and the lower roller with a certain curvature is used to alleviate the overpressure on the edge of the pole piece caused by disturbance, thereby improving the thickness consistency of rolling.

[0015] Furthermore, the rolling pressure of the upper roller and the lower roller is set to 20~100 bar, the roller gap between the upper roller and the lower roller is set to 0~1000um, and the rolling speed of the upper roller and the lower roller is 10~100m / min.

[0016] The beneficial effects of the present invention are: The lower roller of the present invention adopts an arc roller, so as to alleviate the overpressure phenomenon of the edge of the pole piece caused by disturbance, and improve the consistency of rolling thickness. In addition, the present invention can play a pole ear stretching effect by adding special-shaped bosses on the surface of the upper and lower rollers and the pinch rollers. While stretching, the bosses can be heated by the heating devices in the upper and lower rollers, so that the pole ear is heated and softened, making it easier to stretch. Therefore, the present invention can not only improve the stretching synchronization between the blank area of ​​the pole ear and the dressing area, but also improve the consistency of rolling thickness, which has a great positive effect on improving the rolling breakage and pole ear state in the prior art, and can greatly improve the product quality rate.

[0017] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. The specific implementation of the present invention is given in detail by the following embodiments and their accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 It is a structural schematic diagram of the roller press of the present invention; Figure 2 A schematic diagram of a dressing area and a blank area of ​​a tab of a certain lithium-ion battery electrode after coating; Figure 3 It is a schematic structural diagram of the pinch rollers of the pinch stretching mechanism in the roller press of the present invention; Figure 4 It is a structural schematic diagram of the roller mechanism in the roller press of the present invention; Figure 5 It is a structural schematic diagram of a roller mechanism in an existing conventional roller press; Figure 6 The figures are the stretching effect diagrams of the pole tabs of lithium-ion battery pole pieces, wherein figure a is the stretching effect of the pole tabs of a conventional roller mechanism, and figure b is the stretching effect of the pole tabs of the roller mechanism of the present invention; Figure 7 This is a test result diagram of the transverse thickness consistency of lithium-ion battery pole pieces rolled by a conventional roller press; Figure 8 This is a test result diagram of the consistency of the transverse thickness of the lithium-ion battery pole piece rolled by the roller of the roller press of the present invention; Fig. 9 It is a comparison chart of the product quality of the roller press of the present invention and the conventional roller press. DETAILED DESCRIPTION

[0019] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings so that the purpose, features and advantages of the invention can be more clearly understood. It should be understood that the embodiments shown in the accompanying drawings are not intended to limit the scope of the present invention, but are only intended to illustrate the essential spirit of the technical solution of the present invention.

[0020] In the following description, certain specific details are set forth for the purpose of illustrating various disclosed embodiments to provide a thorough understanding of the various disclosed embodiments. However, those skilled in the relevant art will recognize that the embodiments may be practiced without one or more of these specific details. In other cases, well-known devices, structures, and techniques associated with the present application may not be shown or described in detail to avoid unnecessarily obscuring the description of the embodiments.

[0021] Unless the context requires otherwise, throughout the specification and claims, the word "comprise" and variations such as "include" and "have" should be construed in an open, inclusive sense, ie, should be interpreted as "including, but not limited to."

[0022] References throughout the specification to "one embodiment" or "an embodiment" indicate that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of "in one embodiment" or "in an embodiment" in various places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any manner in one or more embodiments.

[0023] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. It should be noted that the term "or" is generally employed in its sense including "and / or" unless the context clearly dictates otherwise.

[0024] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0025] See also Figure 1 As shown, a roller press for lithium-ion battery pole pieces comprises an unwinding mechanism 1, a first clamping and stretching mechanism 2, a rolling mechanism 3, a second clamping and stretching mechanism 4 and a winding mechanism 5 which are arranged in sequence.

[0026] See also Figure 2 As shown, Figure 2 A schematic diagram showing the structure of a lithium-ion battery electrode after coating, wherein the darker areas on the left and right are dressing areas, and the lighter areas on the left, middle and right are blank areas for the pole ears.

[0027] join Figure 3As shown, the surface of the pinch roller 8 located in the first pinching and stretching mechanism 2 and the surface of the pinch roller 8 located in the second pinching and stretching mechanism 4 are both provided with 2 to 8 pinch roller bosses 10 along the circumferential direction, and the height of the pinch roller bosses 10 is 30 to 300 μm and the width is 5 to 60 mm. The pinch roller bosses 10 located on the surface of the pinch roller 8 in the first pinching and stretching mechanism 2 and the pinch roller bosses 10 located on the surface of the pinch roller 8 in the second pinching and stretching mechanism 4 are equal in number and corresponding in position. The distribution positions of the pinch roller bosses 10 on the surface of the pinch roller 8 of the first pinching and stretching mechanism 2 and the surface of the pinch roller 8 of the second pinching and stretching mechanism 4 correspond to the distribution positions of the blank areas of the pole ears of the lithium-ion battery pole piece after coating.

[0028] See also Figure 4 As shown, the roller mechanism 3 includes an upper roller 6 and a lower roller 7, the upper and lower spacing and rolling pressure of which are adjustable, wherein the upper roller 6 is a straight roller that is flat as a whole, and the lower roller 7 is a curved roller with a certain curvature on the surface, and the curvature of the lower roller 7 is Π / 2~Π. The pressurizing method of the roller mechanism 3 is that the upper roller 6 remains fixed and the lower roller 7 is lifted and pressurized by a hydraulic cylinder.

[0029] The surfaces of the upper roller 6 and the lower roller 7 are both provided with 2 to 8 roller bosses 9 with heating function along the circumferential direction, and the height of the roller bosses 9 is 5 to 50 μm and the width is 5 to 60 mm. The number of the roller bosses 9 on the upper roller 6 and the roller bosses 9 on the lower roller 7 are equal and the positions are corresponding. The distribution positions of the roller bosses 9 on the upper roller 6 and the lower roller 7 correspond to the distribution positions of the blank areas of the pole tabs of the lithium-ion battery pole piece after coating.

[0030] Taking the arrangement of three roller bosses 9 as an example, Figure 2 and Figure 3 It can be seen that Figure 3 The pinch roller bosses 10 at the left, middle and right positions on the pinch roller 8 shown in FIG. Figure 2 The positions of the blank areas of the three tabs shown in FIG. Figure 2 and Figure 4 It can be seen that Figure 4 The positions of the three roller bosses shown in FIG. 1 correspond to Figure 2 The positions of the blank areas of the three tabs are shown in FIG.

[0031] Since the width of the electrode dressing area after coating is usually 200~1000mm, and the width of the tab blank area is usually 5~100 mm, the roller bosses 9 at different positions need to be ground and electroplated according to the width of the tab blank area and the dressing area after coating. After grinding and electroplating, the width of each roller boss 9 needs to be slightly smaller than the width of the corresponding tab blank area, and the spacing between two adjacent roller bosses 9 is slightly larger than the width of the corresponding dressing area, so that the edge of the roller boss 9 and the edge of the dressing area can maintain a gap of 0.5~1.5mm.

[0032] The upper roller 6 and the lower roller 7 corresponding to each roller boss 9 are provided with a circulating heat transfer oil circuit for heating the corresponding roller boss 9. The circulating heat transfer oil circuit is injected with circulating heat transfer oil that can be heated at high temperature. The heating temperature of the circulating heat transfer oil can reach 50~200℃.

[0033] See also Figure 5 As shown, Figure 5 The schematic diagram of the roller structure of the existing conventional roller press is shown in Figure 2. Figure 4 and Figure 5 It can be clearly seen that the new roller press of the present invention focuses on optimizing and improving the roller mechanism. Different from the conventional roller structure that uses straight rollers as the upper and lower rollers, the present invention changes the lower roller from a straight roller to an arc roller, and adds roller bosses corresponding to the positions of the blank areas of the pole ears after coating on the upper and lower rollers, and at the same time, circulating heat transfer oil circuits for heating the roller bosses are added at corresponding positions inside the upper and lower rollers.

[0034] The present invention also proposes a lithium-ion battery pole piece stretching and rolling method, the steps of which include: Step 1: According to the overall size of the lithium-ion battery pole piece and the distribution position of the dressing area and the blank area of ​​the pole ear after coating, select the appropriate upper roller 6 and the lower roller 7, and correctly install them on the roller mechanism 3; Step 2: opening the circulating heat transfer oil path disposed inside the upper roller 6 and the lower roller 7 in advance to heat the roller boss 9 disposed on the upper roller 6 and the lower roller 7; Step 3: setting the rolling pressure of the upper roller 6 and the lower roller 7 to 20-100 bar, setting the roller gap between the upper roller 6 and the lower roller 7 to 0-1000 um, and setting the rolling speed of the upper roller 6 and the lower roller 7 to 10-100 m / min; Step 4: The coated lithium-ion battery electrode sheet is led out from the unwinding mechanism 1, and is sequentially passed through the first clamping and stretching mechanism 2, the rolling mechanism 3, and the second clamping and stretching mechanism 4 before being wound on the winding mechanism 5; Step 5: Start the roller press to start pulling, and stop the machine after the lithium-ion battery pole piece is corrected and straightened. At this time, there is a certain gap between the edge of the roller boss 9 and the edge of the adjacent auxiliary material area. After the rolling pressure is increased, the roller press is started again to start pulling, so as to formally stretch and roll the lithium-ion battery pole piece; In step 6, during the rolling process, the roller boss 9 stretches the blank area of ​​the pole lug, and the heating of the roller boss 9 by the circulating heat transfer oil circuit causes the blank area of ​​the pole lug to soften due to the heat, thereby promoting stretching; at the same time, the clamping roller boss 10 further stretches the blank area of ​​the pole lug; and the lower roller 7 with a certain curvature is used to alleviate the overpressure on the edge of the pole piece caused by disturbance, thereby improving the thickness consistency of rolling.

[0035] The following uses the 3914895 model pole piece as the stretching and rolling object to explain the lithium ion battery pole piece stretching and rolling method of the present invention in detail through the following embodiments. After coating, the 3914895 model pole piece has a width of 29 mm for the blank areas on both sides of the pole ears, a width of 156 mm for the dressing area, and a width of 58 mm for the blank area in the middle of the pole ears. Example

[0036] According to the overall size of the 3914895 model pole piece and the distribution position of the dressing area and the blank area of ​​the pole lug after coating, select the appropriate upper roller 6 and lower roller 7. Among them, the upper roller 6 adopts a straight roller that is flat as a whole, and the lower roller 7 adopts a curved roller with a certain curvature on the surface, and the curvature of the lower roller 7 is 0.9Π.

[0037] The upper roller 6 and the lower roller 7 are provided with three shaped roller bosses 9 protruding from the surface of the upper roller 6 and the lower roller 7 on the left, middle and right sides along the circumferential direction. The positions of the three roller bosses 9 on the upper roller 6 and the lower roller 7 correspond to the positions of the three tab blank areas on the 3914895 model pole piece. The height of the three roller bosses 9 is 35um, and the widths of the left, middle and right roller bosses 9 are 28mm / 56mm / 28mm respectively. The upper roller 6 and the lower roller 7 are provided with circulating heat transfer oil circuits for heating the three roller bosses 9 respectively.

[0038] The selected upper roller 6 and the lower roller 7 are correctly installed on the roller mechanism 3. Before starting the stretching rolling, the circulating heat conduction oil circuit is opened in advance, and the hot oil in the circulating heat conduction oil circuit is heated to 130°C to heat the six roller bosses 9 of the upper roller 6 and the lower roller 7. Then, the roller gap between the upper roller 6 and the lower roller 7 is set to 300um, the rolling pressure between the upper roller 6 and the lower roller 7 is set to 45bar, and the rolling speed of the upper roller 6 and the lower roller 7 is set to 50m / min.

[0039] The coated 3914895 model pole piece is led out from the unwinding mechanism 1, and is successively passed through the first pinching and stretching mechanism 2, the roller mechanism 3 composed of the upper roller 6 and the lower roller 7, and the second pinching and stretching mechanism 4, and then is wound on the winding mechanism 5. Among them, the surface of the pinching roller 8 located in the first pinching and stretching mechanism 2 and the surface of the pinching roller 8 located in the second pinching and stretching mechanism 4 are both provided with three pinching roller bosses 10 along the circumferential direction. And the positions of the three pinching roller bosses 10 on the pinching roller 8 correspond to the positions of the three pole tab blank areas on the 3914895 model pole piece. The height of the three pinching roller bosses 10 is 280um, and the widths of the left, middle and right three pinching roller bosses 10 are 28mm / 56mm / 28mm respectively.

[0040] Start the roller press to start pulling. After the 3914895 model pole piece is corrected and straightened, a gap of 0.5 mm is maintained between the edge of the roller boss 9 and the edge of the dressing area. Then stop the machine to apply pressure, and start the roller press again to start pulling, thereby formally stretching and rolling the 3914895 model pole piece. Example

[0041] According to the overall size of the 3914895 model pole piece and the distribution position of the dressing area and the blank area of ​​the pole lug after coating, select the appropriate upper roller 6 and lower roller 7. Among them, the upper roller 6 adopts a straight roller that is flat as a whole, and the lower roller 7 adopts a curved roller with a certain curvature on the surface, and the curvature of the lower roller 7 is 0.9Π.

[0042] The upper roller 6 and the lower roller 7 are provided with three shaped roller bosses 9 protruding from the surface of the upper roller 6 and the lower roller 7 on the left, middle and right sides along the circumferential direction. The positions of the three roller bosses 9 on the upper roller 6 and the lower roller 7 correspond to the positions of the three tab blank areas on the 3914895 model pole piece. The height of the three roller bosses 9 is 35um, and the widths of the left, middle and right roller bosses 9 are 28mm / 56mm / 28mm respectively. The upper roller 6 and the lower roller 7 are provided with circulating heat transfer oil circuits for heating the three roller bosses 9 respectively.

[0043] The selected upper roller 6 and the lower roller 7 are correctly installed on the roller mechanism 3. Before starting the stretching rolling, the circulating heat conduction oil circuit is opened in advance, and the hot oil in the circulating heat conduction oil circuit is heated to 150°C to heat the six roller bosses 9 of the upper roller 6 and the lower roller 7. Then, the roller gap between the upper roller 6 and the lower roller 7 is set to 500um, the rolling pressure between the upper roller 6 and the lower roller 7 is set to 55bar, and the rolling speed of the upper roller 6 and the lower roller 7 is set to 40m / min.

[0044] The coated 3914895 model pole piece is led out from the unwinding mechanism 1, and is successively passed through the first pinching and stretching mechanism 2, the roller mechanism 3 composed of the upper roller 6 and the lower roller 7, and the second pinching and stretching mechanism 4, and then is wound on the winding mechanism 5. Among them, the surface of the pinching roller 8 located in the first pinching and stretching mechanism 2 and the surface of the pinching roller 8 located in the second pinching and stretching mechanism 4 are both provided with three pinching roller bosses 10 along the circumferential direction. And the positions of the three pinching roller bosses 10 on the pinching roller 8 correspond to the positions of the three pole tab blank areas on the 3914895 model pole piece. The height of the three pinching roller bosses 10 is 280um, and the widths of the left, middle and right three pinching roller bosses 10 are 28mm / 56mm / 28mm respectively.

[0045] Start the roller press to start pulling. After the 3914895 model pole piece is corrected and straightened, a gap of 0.8 mm is maintained between the edge of the roller boss 9 and the edge of the dressing area. Then stop the machine to apply pressure, and start the roller press again to start pulling, thereby formally stretching and rolling the 3914895 model pole piece. Example

[0046] According to the overall size of the 3914895 model pole piece and the distribution position of the dressing area and the blank area of ​​the pole lug after coating, select the appropriate upper roller 6 and lower roller 7. Among them, the upper roller 6 adopts a straight roller that is flat as a whole, and the lower roller 7 adopts a curved roller with a certain curvature on the surface, and the curvature of the lower roller 7 is 0.9Π.

[0047] The upper roller 6 and the lower roller 7 are provided with three shaped roller bosses 9 protruding from the surface of the upper roller 6 and the lower roller 7 on the left, middle and right sides along the circumferential direction. The positions of the three roller bosses 9 on the upper roller 6 and the lower roller 7 correspond to the positions of the three tab blank areas on the 3914895 model pole piece. The height of the three roller bosses 9 is 35um, and the widths of the left, middle and right roller bosses 9 are 28mm / 56mm / 28mm respectively. The upper roller 6 and the lower roller 7 are provided with circulating heat transfer oil circuits for heating the three roller bosses 9 respectively.

[0048] The selected upper roller 6 and the lower roller 7 are correctly installed on the roller mechanism 3. Before starting the stretching rolling, the circulating heat conduction oil circuit is opened in advance, and the hot oil in the circulating heat conduction oil circuit is heated to 140°C to heat the six roller bosses 9 of the upper roller 6 and the lower roller 7. Then, the roller gap between the upper roller 6 and the lower roller 7 is set to 300um, the rolling pressure between the upper roller 6 and the lower roller 7 is set to 45bar, and the rolling speed of the upper roller 6 and the lower roller 7 is set to 30m / min.

[0049] The coated 3914895 model pole piece is led out from the unwinding mechanism 1, and is successively passed through the first pinching and stretching mechanism 2, the roller mechanism 3 composed of the upper roller 6 and the lower roller 7, and the second pinching and stretching mechanism 4, and then is wound on the winding mechanism 5. Among them, the surface of the pinching roller 8 located in the first pinching and stretching mechanism 2 and the surface of the pinching roller 8 located in the second pinching and stretching mechanism 4 are both provided with three pinching roller bosses 10 along the circumferential direction. And the positions of the three pinching roller bosses 10 on the pinching roller 8 correspond to the positions of the three pole tab blank areas on the 3914895 model pole piece. The height of the three pinching roller bosses 10 is 280um, and the widths of the left, middle and right three pinching roller bosses 10 are 28mm / 56mm / 28mm respectively.

[0050] Start the roller press to start pulling, and after the 3914895 model pole piece is corrected and straightened, a gap of 1.0 mm is maintained between the edge of the roller boss 9 and the edge of the dressing area, and then the machine is stopped to apply pressure, and the roller press is started again to start pulling, thereby formally stretching and rolling the 3914895 model pole piece. Example

[0051] According to the overall size of the 3914895 model pole piece and the distribution position of the dressing area and the blank area of ​​the pole lug after coating, select the appropriate upper roller 6 and lower roller 7. Among them, the upper roller 6 adopts a straight roller that is flat as a whole, and the lower roller 7 adopts a curved roller with a certain curvature on the surface, and the curvature of the lower roller 7 is 0.9Π.

[0052] The upper roller 6 and the lower roller 7 are provided with three shaped roller bosses 9 protruding from the surface of the upper roller 6 and the lower roller 7 on the left, middle and right sides along the circumferential direction. The positions of the three roller bosses 9 on the upper roller 6 and the lower roller 7 correspond to the positions of the three tab blank areas on the 3914895 model pole piece. The height of the three roller bosses 9 is 35um, and the widths of the left, middle and right roller bosses 9 are 28mm / 56mm / 28mm respectively. The upper roller 6 and the lower roller 7 are provided with circulating heat transfer oil circuits for heating the three roller bosses 9 respectively.

[0053] The selected upper roller 6 and the lower roller 7 are correctly installed on the roller mechanism 3. Before starting the stretching rolling, the circulating heat conduction oil circuit is opened in advance, and the hot oil in the circulating heat conduction oil circuit is heated to 130°C to heat the six roller bosses 9 of the upper roller 6 and the lower roller 7. Then, the roller gap between the upper roller 6 and the lower roller 7 is set to 500um, the rolling pressure between the upper roller 6 and the lower roller 7 is set to 65bar, and the rolling speed of the upper roller 6 and the lower roller 7 is set to 50m / min.

[0054] The coated 3914895 model pole piece is led out from the unwinding mechanism 1, and is successively passed through the first pinching and stretching mechanism 2, the roller mechanism 3 composed of the upper roller 6 and the lower roller 7, and the second pinching and stretching mechanism 4, and then is wound on the winding mechanism 5. Among them, the surface of the pinching roller 8 located in the first pinching and stretching mechanism 2 and the surface of the pinching roller 8 located in the second pinching and stretching mechanism 4 are both provided with three pinching roller bosses 10 along the circumferential direction. And the positions of the three pinching roller bosses 10 on the pinching roller 8 correspond to the positions of the three pole tab blank areas on the 3914895 model pole piece. The height of the three pinching roller bosses 10 is 280um, and the widths of the left, middle and right three pinching roller bosses 10 are 28mm / 56mm / 28mm respectively.

[0055] Start the roller press to start pulling. After the 3914895 model pole piece is corrected and straightened, a gap of 0.7 mm is maintained between the edge of the roller boss 9 and the edge of the dressing area. Then stop the machine to apply pressure, and start the roller press again to start pulling, thereby formally stretching and rolling the 3914895 model pole piece. Example

[0056] According to the overall size of the 3914895 model pole piece and the distribution position of the dressing area and the blank area of ​​the pole lug after coating, select the appropriate upper roller 6 and lower roller 7. Among them, the upper roller 6 adopts a straight roller that is flat as a whole, and the lower roller 7 adopts a curved roller with a certain curvature on the surface, and the curvature of the lower roller 7 is 0.9Π.

[0057] The upper roller 6 and the lower roller 7 are provided with three shaped roller bosses 9 protruding from the surface of the upper roller 6 and the lower roller 7 on the left, middle and right sides along the circumferential direction. The positions of the three roller bosses 9 on the upper roller 6 and the lower roller 7 correspond to the positions of the three tab blank areas on the 3914895 model pole piece. The height of the three roller bosses 9 is 35um, and the widths of the left, middle and right roller bosses 9 are 28mm / 56mm / 28mm respectively. The upper roller 6 and the lower roller 7 are provided with circulating heat transfer oil circuits for heating the three roller bosses 9 respectively.

[0058] The selected upper roller 6 and the lower roller 7 are correctly installed on the roller mechanism 3. Before starting the stretching rolling, the circulating heat conduction oil circuit is opened in advance, and the hot oil in the circulating heat conduction oil circuit is heated to 110°C to heat the six roller bosses 9 of the upper roller 6 and the lower roller 7. Then, the roller gap between the upper roller 6 and the lower roller 7 is set to 400um, the rolling pressure between the upper roller 6 and the lower roller 7 is set to 45bar, and the rolling speed of the upper roller 6 and the lower roller 7 is set to 50m / min.

[0059] The coated 3914895 model pole piece is led out from the unwinding mechanism 1, and is successively passed through the first pinching and stretching mechanism 2, the roller mechanism 3 composed of the upper roller 6 and the lower roller 7, and the second pinching and stretching mechanism 4, and then is wound on the winding mechanism 5. Among them, the surface of the pinching roller 8 located in the first pinching and stretching mechanism 2 and the surface of the pinching roller 8 located in the second pinching and stretching mechanism 4 are both provided with three pinching roller bosses 10 along the circumferential direction. And the positions of the three pinching roller bosses 10 on the pinching roller 8 correspond to the positions of the three pole tab blank areas on the 3914895 model pole piece. The height of the three pinching roller bosses 10 is 280um, and the widths of the left, middle and right three pinching roller bosses 10 are 28mm / 56mm / 28mm respectively.

[0060] Start the roller press to start pulling, and after the 3914895 model pole piece is corrected and straightened, a gap of 0.9 mm is maintained between the edge of the roller boss 9 and the edge of the dressing area. Then stop the machine to apply pressure, and start the roller press again to start pulling, thereby formally stretching and rolling the 3914895 model pole piece. Example

[0061] According to the overall size of the 3914895 model pole piece and the distribution position of the dressing area and the blank area of ​​the pole lug after coating, select the appropriate upper roller 6 and lower roller 7. Among them, the upper roller 6 adopts a straight roller that is flat as a whole, and the lower roller 7 adopts a curved roller with a certain curvature on the surface, and the curvature of the lower roller 7 is 0.9Π.

[0062] The upper roller 6 and the lower roller 7 are provided with three shaped roller bosses 9 protruding from the surface of the upper roller 6 and the lower roller 7 on the left, middle and right sides along the circumferential direction. The positions of the three roller bosses 9 on the upper roller 6 and the lower roller 7 correspond to the positions of the three tab blank areas on the 3914895 model pole piece. The height of the three roller bosses 9 is 35um, and the widths of the left, middle and right roller bosses 9 are 28mm / 56mm / 28mm respectively. The upper roller 6 and the lower roller 7 are provided with circulating heat transfer oil circuits for heating the three roller bosses 9 respectively.

[0063] The selected upper roller 6 and the lower roller 7 are correctly installed on the roller mechanism 3. Before starting the stretching rolling, the circulating heat conduction oil circuit is opened in advance, and the hot oil in the circulating heat conduction oil circuit is heated to 110°C to heat the six roller bosses 9 of the upper roller 6 and the lower roller 7. Then, the roller gap between the upper roller 6 and the lower roller 7 is set to 800um, the rolling pressure between the upper roller 6 and the lower roller 7 is set to 55bar, and the rolling speed of the upper roller 6 and the lower roller 7 is set to 45m / min.

[0064] The coated 3914895 model pole piece is led out from the unwinding mechanism 1, and is successively passed through the first pinching and stretching mechanism 2, the roller mechanism 3 composed of the upper roller 6 and the lower roller 7, and the second pinching and stretching mechanism 4, and then is wound on the winding mechanism 5. Among them, the surface of the pinching roller 8 located in the first pinching and stretching mechanism 2 and the surface of the pinching roller 8 located in the second pinching and stretching mechanism 4 are both provided with three pinching roller bosses 10 along the circumferential direction. And the positions of the three pinching roller bosses 10 on the pinching roller 8 correspond to the positions of the three pole tab blank areas on the 3914895 model pole piece. The height of the three pinching roller bosses 10 is 280um, and the widths of the left, middle and right three pinching roller bosses 10 are 28mm / 56mm / 28mm respectively.

[0065] The roller press is started to start pulling, and after the 3914895 model pole piece is corrected and aligned, a gap of 1.3 mm is maintained between the edge of the roller boss (9) and the edge of the dressing area, and then the machine is stopped to apply pressure, and the roller press is started again to start pulling, thereby formally stretching and rolling the 3914895 model pole piece.

[0066] The applicant of the present invention also compared the roller press and method of the present invention with the conventional roller press and method in terms of tab stretching effect, consistency of rolling transverse thickness, and product quality rate.

[0067] See also Figure 6 As shown, Figure 6 a shows the tab stretching effect of a conventional roller press. Figure 6 b shows the tab stretching effect of the roller press of the present invention. Figure 6 a and Figure 6 b It can be seen that the pole ear stretching effect of the roller press of the present invention is better, while the pole ear of the conventional roller press has wrinkles, overlapping and arching, which is more prone to belt breakage.

[0068] See also Figure 7 and Figure 8 As shown, Figure 7 and Figure 8 The test results of the consistency of the transverse thickness of lithium-ion battery pole pieces rolled by the conventional roller press and the roller press of the present invention are respectively shown. Figure 7 and Figure 8 It can be seen that the roller press of the present invention has greatly improved the consistency of the transverse thickness of the pole piece when rolled. The transverse thickness range of the roller press of the present invention is 2um, while the transverse thickness range of the conventional roller press is 7um.

[0069] See also Fig. 9 As shown, Fig. 9 The product quality comparison between the roller press of the present invention and the conventional roller press is shown. Fig. 9 It can be seen from the comparison results that the roller press of the present invention has a great improvement in the roller pressing yield, which can be increased from 95.5% to 99.2%.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A roller press for lithium-ion battery pole pieces, characterized in that: It comprises an unwinding mechanism (1), a first pinching and stretching mechanism (2), a roller mechanism (3), a second pinching and stretching mechanism (4) and a winding mechanism (5) which are arranged in sequence; The roller mechanism (3) comprises an upper roller (6) and a lower roller (7) whose upper and lower spacings and roller pressures are adjustable; the upper roller (6) is a straight roller that is flat as a whole, and the lower roller (7) is a curved roller whose surface has a certain curvature; the first pinching and stretching mechanism (2) and the second pinching and stretching mechanism (4) both comprise a plurality of corresponding pinching rollers (8).

2. The roller press according to claim 1, characterized in that: The curvature of the lower roller (7) is Π / 2~Π.

3. The roller press according to claim 1, characterized in that: The pressurizing method of the roller mechanism (3) is that the upper roller (6) remains stationary, and the lower roller (7) is lifted and pressurized by a hydraulic cylinder.

4. The roller press according to claim 1, characterized in that: The surfaces of the upper roller (6) and the lower roller (7) are both provided with 2 to 8 roller bosses (9) with heating function along the circumferential direction, the number and distribution positions of the roller bosses (9) located on the upper roller (6) and the roller bosses (9) located on the lower roller (7) correspond to the number and distribution positions of the blank areas of the pole lugs on the pole pieces to be rolled, and each roller boss (9) has a height of 5 to 50 μm and a width of 5 to 60 mm.

5. The roller press according to claim 4, characterized in that: The roller bosses (9) are processed by electroplating, and the distribution positions of the roller bosses (9) correspond to the distribution positions of the tab blank areas of the lithium-ion battery pole piece after coating, and the widths of the roller bosses (9) at different positions are slightly smaller than the widths of the corresponding tab blank areas, and the spacing between two adjacent roller bosses (9) is slightly larger than the widths of the corresponding dressing areas.

6. The roller press according to claim 5, characterized in that: There is a spacing of 0.5 to 1.5 mm between the roller boss (9) and the adjacent dressing area.

7. The roller press according to claim 4, characterized in that: A circulating heat transfer oil circuit for heating the corresponding roller boss (9) is provided in the upper roller (6) and the lower roller (7) corresponding to the position of each roller boss (9), and the circulating heat transfer oil circuit is injected with circulating heat transfer oil capable of high temperature heating, and the circulating heat transfer oil can withstand a heating temperature of 50-200°C.

8. The roller press according to claim 1, characterized in that: The surface of the pinch roller (8) located in the first pinching and stretching mechanism (2) and the surface of the pinch roller (8) located in the second pinching and stretching mechanism (4) are both provided with 2 to 8 pinch roller bosses (10); the number and distribution positions of the pinch roller bosses (10) located on the surface of the pinch roller (8) in the first pinching and stretching mechanism (2) and the pinch roller bosses (10) located on the surface of the pinch roller (8) in the second pinching and stretching mechanism (4) correspond to the number and distribution positions of the blank areas of the pole lugs on the pole piece to be rolled, and each pinch roller boss (10) has a height of 30 to 300 μm and a width of 5 to 60 mm.

9. A method for stretching and rolling a lithium-ion battery pole piece using a roller press as claimed in any one of claims 1 to 8, characterized in that: include: Step 1) according to the overall size of the lithium-ion battery pole piece and the distribution position of the dressing area and the blank area of ​​the pole tab after coating, select the appropriate upper roller (6) and the lower roller (7), and correctly install them on the roller mechanism (3); Step 2) opening the circulating heat transfer oil path provided inside the upper roller (6) and the lower roller (7) in advance to heat the roller bosses (9) provided on the upper roller (6) and the lower roller (7); Step 3) setting the roller gap between the upper roller (6) and the lower roller (7), setting the roller pressure of the upper roller (6) and the lower roller (7), and setting the rolling speed of the upper roller (6) and the lower roller (7); Step 4) The coated lithium-ion battery pole piece is led out from the unwinding mechanism (1), and passes through the first clamping and stretching mechanism (2), the rolling mechanism (3), and the second clamping and stretching mechanism (4) in sequence, and then is wound on the winding mechanism (5); Step 5) starting the roller press to start pulling, and stopping the machine after the lithium-ion battery pole piece is corrected and straightened. At this time, a certain gap is maintained between the edge of the roller boss (9) and the edge of the adjacent auxiliary material area. After the rolling pressure is increased, the roller press is started again to start pulling, thereby formally stretching and rolling the lithium-ion battery pole piece; Step 6) During the rolling process, the roller boss (9) stretches the blank area of ​​the pole lug, and the circulating heat transfer oil circuit heats the roller boss (9), so that the blank area of ​​the pole lug is softened by heat to promote stretching; at the same time, the pinch roller boss (10) further stretches the blank area of ​​the pole lug; and the lower roller (7) with a certain curvature is used to alleviate the overpressure phenomenon of the edge of the pole piece caused by the disturbance, thereby improving the thickness consistency of the rolling.

10. The lithium-ion battery pole piece stretching and rolling method according to claim 9, characterized in that: The rolling pressure of the upper roller (6) and the lower roller (7) is set to 20-100 bar, the roller gap between the upper roller (6) and the lower roller (7) is set to 0-1000 um, and the rolling speed of the upper roller (6) and the lower roller (7) is 10-100 m / min.

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