WO2021190635A1

WO2021190635A1 - Cold-press extension mechanism and cold-press device

Info

Publication number: WO2021190635A1
Application number: PCT/CN2021/083299
Authority: WO
Inventors: 冯俊敏; 吴婷婷; 张万财
Original assignee: 深圳市海瀚新能源技术有限公司
Priority date: 2020-03-26
Filing date: 2021-03-26
Publication date: 2021-09-30

Abstract

A cold-press extension mechanism (100) comprises a drawing assembly (110) and a press roller assembly (120) disposed along a conveying path of the cold-press extension mechanism. The drawing assembly is used to press two side surfaces of a first portion of a film, and the press roller assembly is used to press two side surfaces of a second portion of the film. The drawing assembly and the press roller assembly have a speed difference therebetween, thus allowing the first portion and the second portion of the film to be rolled in a synchronous manner. Further provided is a cold-press extension device. The cold-press extension mechanism draws and rolls different portions of a film by means of the drawing assembly and the press roller assembly respectively, so as to avoid the problem of uneven rolling resulting from inconsistent film thicknesses or other structural issues, thereby preventing inconsistent extension.

Description

Cold pressing extension mechanism and cold pressing device

Cross-references to related applications

This application requires the application number to be submitted to the Chinese Patent Office on March 26, 2020 with the application number 202010226419.4, titled "cold-rolling extension mechanism, cold-pressing device, and cold-rolling extension method", and the application submitted to the China Patent Office on March 26, 2020 The priority of the Chinese patent application with the application number 202020410311.6 and the name "cold-rolling extension mechanism and cold-pressing device", the entire content of which is incorporated into this application by reference.

Technical field

This application relates to the field of cold pressing technology, specifically, to a cold pressing extension mechanism and a cold pressing device.

Background technique

In the lithium battery manufacturing process, due to the different thickness of the film material, the pressure during the cold pressing process is different, and the local area cannot be compressed, and the extension effect is also inconsistent. It is easy to cause broken belt and roll wrinkles. However, the existing cold pressing process cannot meet the requirements of the uniformity of the extension of the current collector.

Summary of the invention

The purpose of this application is to provide a cold-rolling extension mechanism and a cold-pressing device to improve the technical problem of inconsistent cold-rolling extension of the current collector.

In the first aspect, an embodiment of the present application provides a cold-rolling stretching mechanism, including a traction assembly and a pressing roller assembly arranged along the conveying path of the cold-rolling stretching mechanism. The traction assembly is crimped on both sides of the first part of the film, and the pressure roller assembly is crimped on both sides of the second part of the film. Synchronous rolling.

The cold-rolling stretching mechanism separately draws and rolls different parts of the film through the traction assembly and the pressing roller assembly, so as to avoid the problem of inconsistent extension due to inconsistent film thickness or other structural problems resulting in incomplete roll pressing. The traction assembly includes a first driven roller and a first driven roller. The first driven roller drives the film and the first driven roller to move, which does not significantly suppress the film, reducing the probability of damage to the first part of the film .

The pressing roller assembly includes two second active rollers, which can roll the second part of the film with a certain force. This structure enables different parts of the film to be rolled differently to meet the requirements of cold rolling and stretching of the film.

The first driving roller and the second driving roller are used to connect with a motor, and can be driven to rotate at different rolling linear speeds, so that the roller pressing linear speed of the upstream pressing roller assembly is lower than that of the downstream pressing roller assembly. The pressing line speed can stretch and stretch the tab area of the film material to match the extension produced after the press roller assembly rolls the film coating area, avoiding the tab area after the press roller assembly is not stretched, and the tape is running. Most of the tension acts on the tab area, leading to broken belts or partial wrinkles of the membrane material, and at the same time avoiding the wavy edge caused by the membrane flowing into the subsequent process, resulting in a low yield.

In a possible implementation manner, the roller surface distance between the first driven roller and the first driving roller is less than or equal to the thickness of the first part in the width direction of the film, and the roller surface distance of the two second driving rollers is less than the film material. The thickness of the second part in the width direction.

Since the first driven roller is driven by the first driving roller and the film to rotate, the distance between the first driven roller and the first driving roller is less than or equal to the thickness of the first part in the width direction of the film. It can ensure the interaction between the first driven roller and the first driving roller and the film material, so that the first part of the film material is fully stretched. The distance between the roller surfaces of the two second active rollers is smaller than the thickness of the second part of the film in the width direction. It is a roller that has a certain effect on the second part of the film, so that the thickness of the second part of the film becomes thinner. The material becomes compact.

In a possible implementation manner, the traction assembly includes two first driven rollers and a first driving roller, the roller width of the first driven roller is not greater than the width of the first part of the film, and the roller of the first driving roller The width is not less than the width of the film material, and the two first driven rollers are respectively arranged close to the two sides of the conveying path for pulling the two edges of the film material.

In a possible implementation, the traction assembly includes two first driven rollers and a first driving roller. The width of the first driven roller and the width of the first driving roller are the same as those of the first part of the film. The width is the same.

In a possible implementation, the traction assembly includes two first driven rollers and a first driving roller. The width of the first driven roller is the same as the width of the first part of the film. The roller of the first driving roller The width is the same as that of the film material.

In a possible implementation, the traction assembly includes four first driven rollers and a first driving roller. The four first driven rollers correspond to the first parts of the four film materials, and one first driving roller is arranged at Below the membrane.

In the actual cold pressing process, the membrane material may have multiple first parts. When the two ends of the membrane material in the width direction respectively have first parts, the above structure can simultaneously cold-roll the two first parts. The roll width of the first driven roller is not greater than the width of the first part of the film, and this structure prevents the first driven roller from interfering with the adjacent second part. The roll width of the first active roll is not less than the width of the film material, and this structure can provide sufficient support for the film material.

In a possible implementation manner, the traction assembly further includes at least one third driven roller, and at least one third driven roller is disposed between the two first driven rollers for cooperating with the first driving roller to align The membrane is pulled. When the film material is multiple, the third driven roller, the first driven roller and the first driving roller are used to cooperate to act on the tab area of the film material.

In a possible implementation, the roller surface of the first driven roller is an elastic roller surface, and the distance between the first driven roller and the first driving roller is less than or equal to the thickness of the first part in the width direction of the film. The distance between the roller surfaces of the two second driving rollers is smaller than the thickness of the second part in the width direction of the film.

Since the first driven roller is driven by the first driving roller and the film to rotate, the distance between the first driven roller and the first driving roller is less than or equal to the thickness of the first part in the width direction of the film. It can ensure the interaction between the first driven roller and the first driving roller and the film material, so that the first part of the film material is fully stretched. The distance between the roller surfaces of the two second active rollers is smaller than the thickness of the second part in the width direction of the film material. It is a roller that has a certain effect on the second part of the film material, so that the thickness of the second part of the film material becomes thinner. The material becomes compact.

In a possible implementation manner, the cold rolling and stretching mechanism includes two sets of traction components, and the two sets of traction components are respectively located upstream and downstream of the pressure roller assembly. This structure enables the film material to be provided with traction components before and after the rollers of the pressing roller assembly, so that the film material can be fully cold-rolled and stretched.

In a possible implementation manner, a heating device for heating the film material is further included, and the heating device is arranged between the traction assembly and the pressing roller assembly.

The film material has different elongation at break, and it is easy to break the belt during the pressing and stretching process. Therefore, a heating device is set to heat the film material to increase the deformation rate of the film material and reduce the occurrence rate of the belt breakage.

In a possible implementation, the edge of the first driven roller is a chamfered structure;

In a possible implementation manner, the edge of the first driven roller has a rounded or beveled structure. Optionally, the angle of the oblique angle includes but is not limited to any one of the following angles: 15 degrees, 30 degrees, 45 degrees, or 60 degrees.

The first part and the second part of the film are arranged adjacently, and the pressing roller is easy to press to the side part. Setting the edge of the first driven roller into a rounded or beveled structure can reduce the pressing of the side part while sufficiently pressing the first part.

In a second aspect, a cold-rolling and stretching device is provided, which includes the above-mentioned cold-rolling and stretching mechanism.

The device includes the above-mentioned cold rolling and stretching mechanism, which can respectively roll different parts of the film material, avoiding the problem of inconsistent stretching caused by inconsistent film thickness or other structural problems.

In a third aspect, there is provided a cold-rolling and stretching method, using the above-mentioned cold-rolling and stretching device for cold-rolling and stretching, which includes: Crimping speed.

In this method, by setting a speed difference during rolling, the film between the traction assembly and the pressing roller assembly is stretched in the direction of the conveying path, and the extension of the pole piece is improved.

In a possible implementation, there are two sets of traction components, which are respectively located upstream and downstream of the pressure roller assembly, and the traction linear velocity of the upstream traction component is 97%-99% of the roller pressure linear velocity of the pressure roller assembly , The rolling linear velocity of the pressing roller assembly is 97%-99% of the traction linear velocity of the traction assembly located downstream.

This structure enables the film to be stretched before and after the roll, thereby increasing the elongation rate of the film. Within this speed difference range, the film material can be fully stretched and stretched without causing the film material to break.

A cold-rolling and stretching mechanism for rolling film materials, comprising a traction assembly and a pressing roller assembly arranged along the conveying path of the cold-rolling and stretching mechanism;

The traction assembly is used to traction the first part in the width direction of the film. It includes a first driven roller and a first driving roller that are arranged in pairs. The first driving roller is used for transmission connection with the first driving device. The roller is used to rotate with the movement of the film; the pressing roller assembly is used to roll the second part in the width direction of the film, which includes two second active rollers arranged in pairs, both of which are used It is in transmission connection with the second driving device.

Description of the drawings

FIG. 1 is a schematic diagram of the first structure of a cold-rolling stretching mechanism provided by an embodiment of the application;

2 is a schematic diagram of the second structure of the cold rolling and stretching mechanism provided by the embodiment of the application;

FIG. 3 is a schematic diagram of a third structure of a cold rolling and stretching mechanism provided by an embodiment of the application;

4 is a schematic diagram of a structure of a diode provided by an embodiment of the application;

FIG. 5 is a schematic structural diagram of a traction assembly provided by an embodiment of the application;

Fig. 6 is a schematic structural diagram of a quadrupole provided by an embodiment of the application;

FIG. 7 is a schematic diagram of the second structure of the traction assembly provided by the embodiment of the application.

Icon: 100-cold rolling and stretching mechanism; 101-pole piece; 102-ear ear area; 103-coating area; 105-active coating; 110-traction assembly; 111-first driven roller; 113-first driving Roller; 117-third driven roller; 120-pressing roller assembly; 121-second driving roller; 130-heating device.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments It is a part of the embodiments of the present application, but not all of the embodiments. The components of the embodiments of the present application generally described and shown in the drawings herein may be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of the application. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of this application.

In the description of this application, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "vertical", etc. The orientation or positional relationship that is usually placed is only for the convenience of describing the application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as Restrictions on this application. In addition, the terms "first", "second", etc. are only used for distinguishing description, and cannot be understood as indicating or implying relative importance.

Hereinafter, some embodiments of the present application will be described in detail with reference to the accompanying drawings.

Please refer to FIG. 1, FIG. 2 and FIG. 3. FIG. 1, FIG. 2 and FIG. 3 are structural schematic diagrams of different embodiments of the cold rolling and stretching mechanism 100, respectively.

In the present application, a cold-rolling and stretching mechanism 100 is used to roll film materials, and includes a traction assembly 110 and a pressing roller assembly 120 that are arranged along the conveying path of the cold-rolling and stretching mechanism 100. With reference to Figures 4 and 6, the traction assembly 110 is used to draw and roll the first part of the film in the width direction, and the pressing roller assembly 120 is used to draw and roll the second part of the film in the width direction, so that the film From one end of the conveying path to the other end, that is, under the cooperation of the traction assembly 110 and the pressing roller assembly 120, the traction assembly 110 and the pressing roller assembly 120 respectively roll different areas on the film, and the traction assembly 110 and the pressing roller assembly 120 respectively. The roller assembly 120 simultaneously rolls the upper film surface and the lower film surface of different regions of the film material to ensure that each part is stretched. Among them, the surface of the film material has a conductive layer, and a part of the surface of the conductive layer has a coating. The “first part” refers to the part without coating and the thinner part, and the “second part” refers to the part with the coating and the thicker part. The first part and the second part are arranged offset in the width direction. For example, in the width direction, the various parts of the film can be distributed as follows: first part-second part, or first part-second part-first part, or first part-second part-first part-second part, first part and The width of the second part may be the same or different, and the width of each first part or second part may also be the same or different.

In order to ensure a better stretch effect of the film as a whole, the stretch effect of each area of the film is relatively consistent. The traction assembly 110 and the pressing roller assembly 120 have a speed difference. By adjusting the speed of the traction assembly 110 and the pressing roller assembly 120, the film Stretch in the length direction.

Wherein, both the traction assembly 110 and the pressing roller assembly 120 may be at least two rollers crimping on the film surface and the lower film surface. The two rollers of the traction assembly 110 may be both driving rollers, or one driving roller and one driven roller. The two rollers of the pressing roller assembly 120 may both be driving rollers, or one driving roller and one driven roller. Optionally, the width of the roller surface is adapted to the width of the film, and the width of the roller surface of the traction assembly 110 and the pressing roller assembly 120 is slightly smaller than the width of the film.

In this embodiment, the film material is the pole piece 101 in the battery field as an example for description.

FIG. 4 is a schematic diagram of the structure of the pole piece 101. The pole piece includes a tab area 102 and a coating area 103 that are staggered in the width direction (the left and right directions in FIG. 4). The coating area 103 can be coated with coatings, including but not limited to positive electrode coating and negative electrode coating. In this embodiment, the first part is the tab 102 area of the pole piece 101, and the second part is the coating area 103.

The positive polarity material coating may be at least one of the following materials: lithium iron phosphate, lithium cobalt oxide, ternary material, and lithium manganate. The negative material coating may be at least one of the following materials: graphite, lithium titanate, and silicon.

The existing pole piece 101 includes a tab region 102 and an active coating 105 coated on the surface of the tab region. Since the active coating 105 is coated on a part of the tab area, the thickness of the structure of the pole piece 101 is not uniform. During the cold pressing of the pole piece 101, due to the inconsistency of thickness, the lug region 102 with a thin thickness cannot be rolled and extended sufficiently, resulting in the inconsistent extension of the pole piece 101 and the problem of band breakage or wrinkles.

In this application, the traction assembly 110 is used to draw the thinner part (the lug area 102 of the pole piece 101), and the pressing roller assembly 120 rolls the thicker part (the coating area 103 of the pole piece 101).

The traction assembly 110 includes a first driven roller 111 and a first driving roller 113 that are arranged in pairs, and the first driving roller 113 is used to interact with the first driving device (in this embodiment, both the first driving device and the second driving device may be Motor, in other embodiments, the above-mentioned first driving device and second driving device can also be driven by adaptive selection of other driving methods as required) transmission connection, and the first driven roller 111 is used to follow the movement of the film material. Rotate. It can be understood that the first driven roller 111 and the first driving roller 113 are respectively arranged on the upper and lower surfaces of the film material, and the first driving roller 113 is driven by the first driving device (ie, the motor) to rotate, thereby driving the first driven roller 111 and the first driving roller 113 to rotate. The film material of a driving roller 113 moves. The first driven roller 111 is in contact with the film material and has a certain force, so that the film material can drive the first driven roller 111 to rotate, so that the traction assembly 110 realizes the traction of the film material.

In some embodiments of the present application, the distance between the roller surfaces of the first driven roller 111 and the first driving roller 113 is less than or equal to the thickness of the first portion in the width direction of the film. This structure enables the first driving roller 113 to drive the first driven roller 111 to rotate. Optionally, the roller surface of the first driven roller 111 is made of rubber, and there is a certain friction between the rubber and the pole piece 101. The material of the roller surface of the first driven roller 111 and the first driving roller 113 may be nitrile rubber, polyurethane, nylon or silicone.

Please refer to FIG. 2, in some embodiments of the present application, the first driven roller 111 is disposed above the first driving roller 113, that is, the first driving roller 113 is fixed on the lower surface of the film, and has the function of supporting the film. , The roller shaft of the first driven roller 111 is fixed on the upper surface of the film by an air cylinder (not shown) and is arranged directly above the first driving roller 113. The air cylinder is used to control the pressing force of the first driven roller 111 , It can maintain pressure within the range of cylinder stroke. This structure enables the first driven roller 111 to adjust the distance between the first driven roller 111 and the first driving roller 113 according to the thickness of the film material, so that the rolling and stretching force of the traction assembly 110 on the film material is consistent, and avoiding the film material A part (the lug area 102 of the pole piece 101) changes in thickness resulting in inconsistent forces, which leads to the problem of band breakage and wrinkles in the film.

In this embodiment, the mass of the first driven roller 111 is very small, and it is directly placed on the upper surface of the film material without damaging the surface of the film material. The first driven roller 111 is automatically adjusted according to the thickness of the film material. The distance between a driving roller 113. In other embodiments of the present application, the first driven roller 111 is controlled by an electronic device, and the first driven roller 111 is adjusted accordingly according to the thickness data of the film detected by the electronic device. The distance from the first driving roller 113 makes the force of the pulling assembly 110 on the first part of the film consistent.

The width of the roller surface of the first driven roller 111 and the first driving roller 113 in this application matches the width of the first part of the film. It should be noted that the width in this embodiment refers to a dimension horizontal to the direction of the conveying path. In another possible implementation example, the roller surface width of the first driven roller 111 is the same as the width of the tab area 102 of the pole piece 101, and the roller surface width of the first driving roller 113 is the same as the width of the pole piece 101. The first active roller 113 of this structure provides better support for the pole piece 101.

Since the thickness of the tab region 102 is smaller than the thickness of the coating region 103, the first driven roller 111 is likely to touch the coating region 103 next to it when the tab region 102 is rolled. In order to prevent the first driven roller 111 from pressing to the coating area 103 and at the same time to prevent the first driven roller 111 from being unable to press the tab area 102, the roller edge of the first driven roller 111 has a rounded or beveled structure. It should be noted that in some embodiments of the present application, the first driving roller 113 and the first driven roller 111 rotate completely synchronously, so that their linear speeds are the same.

In the actual cold pressing process, the number of pole pieces 101 is generally more than one, that is, the cold-pressed film material is a plurality of pole pieces 101 connected together. Referring to FIGS. 4 and 5, when the film material is a diode piece 101, the two ends of the film material in the width direction are the tab regions 102, and the middle is the coating region 103. The traction assembly 110 includes two first driven rollers 111 and a first driving roller 113. The roller width of the first driven roller 111 is equal to the width of the lug area 102 of the pole piece 101, and the roller width of the first driving roller 113 is equal to the width of the lug area 102 of the pole piece 101. The width of the entire film material is the same, and the two first driven rollers 111 are respectively arranged close to the two sides of the conveying path for pulling the tab regions 102 on the two edges of the pole piece 101. The thickness of the film in this application is small, so the first driving roller 113 can be a roller. If the thickness of the film is large, each first driven roller 111 corresponds to a first driving roller 113 to align the film. The first part of the material is fully hauled.

6 and 7, when the film material is a quadrupole piece 101, the film material has four tab regions 102 and two coating regions 103 in the width direction, and the two tab regions 102 in the middle are connected to Together. In a possible implementation example, the traction assembly 110 includes four first driven rollers 111 (not shown) and a first driving roller 113, and the four first driven rollers 111 correspond to the four tab regions 102 respectively. , A first active roller 113 is arranged under the pole piece 101. In another possible implementation example, the traction assembly 110 includes two first driven rollers 111, a third driven roller 117 and a first driving roller 113. The difference between the structure of the third driven roller 117 and the first driven roller 111 is only that: the roller surface width of the third driven roller 117 is twice the roller surface width of the first driven roller 111. This structure allows the tab area 102 at the middle of the pole piece 101 to be fully extended, avoiding a gap between the two separate first driven rollers 111 and affecting the extension of the pole piece 101. Compared with using multiple active rollers with the same width as the width of the tab area 102, the first active roller 113 with the same width as the film material in this application can provide better support for the film and avoid multiple active rollers. The inconsistent linear speed of rotation leads to the inconsistent extension of the 101 region of the opposing pole piece, which leads to the problem of wrinkles or broken belts. In some embodiments of the present application, the roller shafts of the two first driven rollers 111 and the roller shaft of the third driven roller 117 are independently arranged, and this structure avoids the mutual influence between the rollers.

The pressing roller assembly 120 includes two second driving rollers 121 arranged in pairs, and both of the second driving rollers 121 are used for drivingly connecting with a second driving device (not shown in the figure, namely a motor). It can be understood that two second driving rollers 121 are respectively provided on the upper and lower surfaces of the film, and both of the second driving rollers 121 are driven by the motor to rotate, so that the two second driving rollers 121 rotate synchronously. In the embodiment of the present application, in order to make the linear speeds of the two second active rollers 121 the same, the roller diameters of the two second active rollers 121 are the same. In other embodiments of the present application, the With different roll diameters, there is a difference in linear velocity, so that the upper and lower surfaces of the film are subjected to different forces, and the second part of the film is stretched.

During the cold pressing process, the coating area 103 of the pole piece 101 needs to be pressed, so that the active coating 105 on the coating area 103 becomes compact. In the embodiment of the present application, the roller surface distance of the two second active rollers 121 is smaller than the thickness of the second part in the width direction of the film, that is, the roller surface distance of the two second active rollers 121 is smaller than the coating area of the pole piece 101 The thickness of 103 and the specific roller surface distance of the two second active rollers 121 are adjusted according to actual needs, which is not limited in this application.

In a two-out or one-out multi-pole piece 101, the width of the coating area 103 is the same, so the width of the second active roller 121 is adjusted according to the width of the coating area 103 of the pole piece 101, so that it is not smaller than the coating area 103 The width. In the embodiment of the present application, the roll width of the second active roll 121 is larger than the width of the film material. The roller surface of the second active roller 121 in the present application is plated with a hard plating layer, such as hard chrome plating, ceramic plating, etc., and the surface roughness is required to be low to reduce damage to the surface of the film material.

Since the width of the tab area 102 on the pole piece 101 is smaller than the width of the coating area 103, in some embodiments of the present application, the diameters of the first driven roller 111 and the first driving roller 113 are both smaller than that of the second driving roller 121 diameter. This structure helps to improve the stability of the pressure roller.

In the embodiment of the present application, the traction assembly 110 and the pressing roller assembly 120 sequentially draw and roll the film. The arrangement of the traction assembly 110 and the pressing roller assembly 120 can be set as required, that is, the traction assembly 110 is arranged on the pressing roller assembly. 120 upstream or downstream. When the film is rolled, the first driving roller 113 and the second driving roller 121 are driven to rotate, and the film is driven by the first driving roller 113 and the second driving roller 121 to move along the conveying path. In order to fully and uniformly extend the lug area 102 and the coating area 103 of the pole piece 101, a heating device 130 is provided between the traction assembly 110 and the pressing roller assembly 120 to heat the film. The heating device in this application The heating area of 130 may be the tab area 102 of the membrane material or the entire membrane material. Before rolling, the heating device 130 is turned on, and the temperature of the pole piece 101 increases, which is prone to deformation during stretching and rolling, and it is not easy to produce defects and cause belt breakage, which is beneficial to improve the production yield. The heating device 130 can centrally heat the lug area 102 of the pole piece 101, or it can heat the pole piece 101 as a whole. The heating device 130 in this application can heat the air with a heating bag and blow it onto the pole piece 101, or Is electromagnetic induction heating, or infrared heating, etc.

Further, in order to improve the cold rolling and stretching of the film, in some embodiments of the present application, the cold rolling and stretching mechanism 100 includes two sets of traction assemblies 110, which are respectively arranged upstream and downstream of the pressing roller assembly 120. Before and after the pressing roller assembly 120 rolls the film, the film is stretched to achieve the goal of full stretch. In order to reduce the breakage of the film, a heating device 130 is provided between the pressing roller assembly 120 and the upstream and downstream traction assemblies 110.

The cold-rolling stretching mechanism 100 uses the traction assembly 110 and the pressing roller assembly 120 to respectively roll different parts of the film, so as to avoid the problem of inconsistent stretching caused by inconsistent film thickness or other structural problems. The traction assembly 110 and the pressing roller assembly 120 are respectively connected with a motor, and the linear speed of the first driving roller 113 is different from the linear speed of the second driving roller 121 by driving separately, so as to realize the stretching of the film.

The application also provides a cold-rolling and stretching device (not shown), including the above-mentioned cold-rolling and stretching mechanism 100. The motor) is drivingly connected with the second driving roller 121. The device can realize the difference between the rolling linear speed of the first driving roller 113 and the rolling linear speed of the second driving roller 121 through the control of the motor, and realize the full extension of the film tab area 102.

The present application also provides a cold-rolling and stretching method, which adopts the above-mentioned cold-rolling and stretching device to perform cold-rolling and stretching, which includes: adjusting a motor to make the rolling linear velocity of the pressure roller assembly located upstream of the conveying path lower than that of the pressure roller assembly located downstream The rolling line speed. Among them, the upstream pressing roller assembly and the downstream pressing roller assembly are the traction assembly and the pressing roller assembly respectively, and specific positions are set according to needs. In this method, by setting a speed difference during rolling, the film between the traction assembly and the pressing roller assembly is stretched in the direction of the conveying path, and the extension of the pole piece is improved.

In some embodiments of the present application, the traction assembly is arranged upstream of the pressing roller assembly. The traction linear speed of the first driving roller is lower than the rolling linear speed of the second driving roller. Since the pole piece is stretched, part of the deformation will rebound after the tension is released. Adjust the rolling speed according to the nature of the material. In some embodiments of the present application, the traction linear speed of the first driving roller is 97%-99% of the rolling linear speed of the second driving roller. Within this speed difference range, the film material can be fully stretched and stretched without causing the film material to break. Optionally, the traction linear speed of the first driving roller is 97%, 98%, or 99% of the rolling linear speed of the second driving roller.

Furthermore, the cold-rolling stretching device stretches the film material first and then rolls it, which can act on materials with low elongation at break, avoiding insufficient extension of the tab area and leading to strip breaks when passing over the roll (that is, the press roll assembly). In some embodiments of the present application, a heating device is provided between the traction component and the pressing roller component to heat the film material, so that the temperature of the film material rises, and deformation is more likely to occur during stretching, thereby avoiding belt breakage. Among them, the heating device can focus on heating part of the film material (such as the tab area of the pole piece), and can also heat the film material in the entire width range, which is not limited in this application.

In some embodiments of the present application, the traction assembly is arranged downstream of the pressing roller assembly. The rolling linear speed of the second driving roller is lower than the pulling linear speed of the first driving roller. Further, the rolling linear velocity of the second active roller is 97%-99% of the traction linear velocity of the first active roller. Within this speed difference range, the film material can be fully stretched and stretched without causing the film material to break.

The cold rolling and stretching device of this structure rolls the film first and then stretches it, and it is not recommended to act on materials with low elongation at break. The materials with higher elongation at break are suitable for the cold rolling and stretching devices of the above two structures. Similarly, a heating device is used to heat the film between the traction assembly and the pressing roller assembly to increase the deformation rate of the film. In the method of this application, the heating device is a general device in the field, which is not limited by this application.

In some embodiments of the present application, there are two sets of traction components, which are located upstream and downstream of the pressure roller assembly, respectively. The traction linear speed of the upstream traction assembly is 97%-99% of the roller pressure linear speed of the pressure roller assembly. The rolling linear velocity of the pressing roller assembly is 97%-99% of the traction linear velocity of the traction assembly located downstream. This structure enables the film to be stretched before and after the roll, which improves the extension of the film and makes the film subject to uniform extension.

There is a heating device between the first conveying assembly and the second conveying assembly. The heating device is used to heat the film. The heating is turned on before the first driving device (ie, the motor) and the second drive device (ie, the motor) are started. Device to heat the membrane material. Then turn on the upstream and downstream motors, adjust the speed so that the upstream and downstream traction assembly and the pressure roller assembly reach the preset roller pressing linear speed difference. Then the film material is cold rolled and stretched.

By setting the speed difference, this method makes the film between the traction assembly and the pressing roller assembly be stretched in the direction of the conveying path, the stretching area is larger, and the extension of the pole piece is improved. Combining the heating device to heat the film material makes the film material easy to deform during the stretching process, avoids the problem of tape breakage of the film material, and helps to improve the production yield, which can be increased by 0.3%.

The features and performance of the present application will be further described in detail below in conjunction with embodiments.

Example 1

This embodiment provides a cold rolling and stretching method, the film material is a positive pole piece, including:

The cold-rolling and stretching device provided in the present application is used for cold-rolling and stretching. The cold-rolling and stretching device includes a traction component and a pressure roller component, and the traction component is arranged upstream of the pressure roller component.

Turn on and adjust the motor so that the traction linear velocity of the traction assembly is 98.5-99% of the rolling linear velocity of the pressing roller assembly, and then start to cold-roll the positive pole piece.

Example 2

This embodiment provides a cold rolling and stretching method. The difference from Embodiment 1 is only:

In the cold pressing and stretching mechanism, an electric heating device is arranged between the traction assembly and the pressing roller assembly. Before cold pressing, turn on the electric heating device to increase the temperature of the tab area of the positive pole piece to 100℃-200℃. Then turn on the motor for cold pressing.

Example 3

The traction assembly is arranged downstream of the pressing roller assembly. Turn on and adjust the motor so that the rolling linear velocity of the pressing roller assembly is 98.5-99% of the traction linear velocity of the traction assembly.

Example 4

The cold-rolling and stretching device provided in the present application is used for cold-rolling and stretching. The cold-rolling and stretching device includes two traction components and a pressure roller component, and the two traction components are respectively arranged upstream and downstream of the pressure roller component.

Turn on and adjust the two motors so that the traction line speed of the traction assembly located upstream is 98.5-99% of the rolling line speed of the pressure roller assembly, so that the rolling line speed of the pressure roller assembly is the traction line of the traction assembly located downstream The speed is 98.5-99%, and then the positive electrode sheet is cold-rolled and stretched.

Example 5

This embodiment provides a cold-rolling stretching method. The difference from Embodiment 4 is only:

In the cold rolling and stretching mechanism, electric heating devices are installed between the upstream and downstream traction components and the pressure roller components. Before cold pressing, first turn on the electric heating device to increase the temperature of the lug area of the positive pole piece to 100 ~ 250 ℃. Then turn on the two motors for cold pressing.

Comparative example 1

This comparative example provides a cold rolling and stretching method. The difference from Example 1 is only:

In the cold pressing process, there is no traction component, only the pressure roller component, and only the pressure roller component is used to cold press the film.

The positive electrode sheets of Examples 1-5 and Comparative Example 1 after cold rolling were selected to observe whether there are wrinkles or broken belts on the surface of the positive electrode sheets. The results show that the surface of the positive electrode sheets provided in Examples 1-5 are flat without wrinkles or breaks. However, the tab area of the positive electrode sheet provided in Comparative Example 1 has wrinkles.

The elongation rate of the tab area and the production yield rate of the above-mentioned positive electrode were tested respectively. The test results are as follows:

Table 1 Test results

To	极耳区延伸率Elongation of the ear area	生产优率Production advantage rate
实施例1Example 1	3.5-5‰3.5-5‰	85.0％85.0%
实施例2Example 2	3.5－5‰3.5-5‰	88.7％88.7%
实施例3Example 3	3.5－5‰3.5-5‰	87.5％87.5%
实施例4Example 4	7－10‰7-10‰	92.4％92.4%
实施例5Example 5	7－10‰7-10‰	98.0％98.0%
对比例1Comparative example 1	0‰0‰	0.0％0.0%

It can be seen from Table 1 that the methods provided in Examples 1 to 5 can effectively extend the tab area and improve the production yield of the positive electrode sheet to varying degrees. Heating the tab area helps to soften the foil, reduce tape breaks, and further improve the yield. Among them, the cold rolling and stretching method of Example 5 has the highest production yield. It is explained that in Example 5, heating and stretching are performed on the front and back of the roll, and stretching and stretching in sections has a better effect on the production efficiency.

The above descriptions are only preferred embodiments of the application, and are not intended to limit the application. For those skilled in the art, the application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included in the protection scope of this application.

Industrial applicability

This application provides a cold-rolling stretching mechanism, which draws and rolls different parts of the film through a traction component and a pressing roller component, so as to avoid incomplete rolling due to inconsistent thickness of the film or other structural problems, resulting in stretching The problem of inconsistency. The cold rolling and stretching method provided by the present application sets a speed difference, so that the film between the traction assembly and the pressing roller assembly is stretched in the direction of the conveying path, and the stretching area is larger, which improves the extension of the pole piece. Combining the heating device to heat the film material makes the film material easy to deform during the stretching process, avoids the problem of tape breakage of the film material, and helps to improve the production yield, which can be increased by 0.3%.

Claims

A cold-rolling and stretching mechanism for rolling film materials, characterized in that it comprises a traction assembly and a pressing roller assembly arranged along the conveying path of the cold-rolling and stretching mechanism;

The traction assembly is used to traction the first part in the width direction of the film, and includes a first driven roller and a first driving roller that are arranged in pairs, and the first driving roller is used for transmission connection with a first driving device, The first driven roller is used to rotate with the movement of the film;

The pressing roller assembly is used to roll the second part in the width direction of the film, and includes two second driving rollers arranged in pairs, and both of the second driving rollers are used for transmission with the second driving device. connect.
A cold rolling and stretching mechanism for rolling a film material, characterized in that it comprises a traction assembly and a pressing roller assembly arranged along the conveying path of the cold pressing and stretching mechanism, and the traction assembly is crimped on the first part of the film. On both sides, the pressing roller assembly is crimped on the two sides of the second part of the film, and the traction assembly and the pressing roller assembly have a speed difference, so that the first part of the film and the second part of the film have a speed difference. Two parts of synchronous rolling.
The cold-rolling stretching mechanism according to claim 2, wherein the traction assembly includes two first driven rollers and a first driving roller, and the roller width of the first driven roller is not larger than that of the film The width of the first part of the material, the width of the first driving roller is not less than the width of the film, and the two first driven rollers are respectively arranged close to the two sides of the conveying path to align the two sides of the film. Traction at the edge.
The cold-rolling stretching mechanism according to claim 3, wherein the traction assembly includes two first driven rollers and one first driving roller, and the width of the first driven roller is The width of the first active roller is the same as the width of the first part of the film.
The cold-rolling stretching mechanism according to claim 3, wherein the traction assembly includes two first driven rollers and one first driving roller, and the roller width of the first driven roller is the same as that of the first driven roller. The width of the first part of the film material is the same, and the roll width of the first driving roller is the same as the width of the film material.
The cold-rolling stretching mechanism according to claim 2, wherein the traction assembly includes four first driven rollers and a first driving roller, and the four first driven rollers correspond to the four first driven rollers respectively. In the first part of the film material, one of the first active rollers is arranged below the film material.
The cold-rolling stretching mechanism according to any one of claims 3-6, wherein the traction assembly further comprises at least one third driven roller, and the at least one third driven roller is arranged on the two Between the first driven rollers, they are used to cooperate with the first driving roller to draw the film.
The cold-rolling stretching mechanism according to any one of claims 3-7, wherein the roller surface of the first driven roller is an elastic roller surface, and the first driven roller and the first driving roller The roller surface distance of is less than or equal to the thickness of the first part in the width direction of the film, and the roller surface distance of the two second active rollers is less than the thickness of the second part in the width direction of the film.
The cold-rolling and stretching mechanism according to any one of claims 2-8, wherein the cold-rolling and stretching mechanism comprises two sets of the traction assembly, and the two sets of the traction assembly are respectively located upstream of the pressure roller assembly And downstream.
The cold-rolling stretching mechanism according to any one of claims 2-9, further comprising a heating device for heating the film material, the heating device being arranged between the traction assembly and the pressing roller assembly .
The cold-rolling stretching mechanism according to any one of claims 3-8, wherein the edge of the first driven roller is a chamfered structure.
The cold rolling and stretching mechanism according to claim 11, wherein the edge of the first driven roller has a rounded or beveled structure.
A cold-rolling and stretching device, characterized by comprising the cold-rolling and stretching mechanism according to any one of claims 2 to 12.