Hot stretching device for lithium battery pole piece rolling process

Abstract

The utility model belongs to the technical field of pole piece rolling, and particularly discloses a lithium battery pole piece rolling procedure hot stretching device which comprises an outer roller, an inner barrel is installed in the outer roller, the outer roller and the inner barrel are coaxial, a heating mechanism is installed in an inner cavity of the inner barrel, a plurality of heat conduction channels are evenly arranged between the outer roller and the inner barrel in the circumferential direction, and the heat conduction channels are communicated with the inner barrel. The two ends of the outer roller and the two ends of the inner roller are connected with shaft sleeves in a sealed mode, and the other ends of the shaft sleeves are fixedly connected with rotating mechanisms. The outer roller is sleeved with a plurality of heat conduction sleeves used for tightly pressing a pole piece tab area, and a heat insulation sleeve used for tightly pressing a pole piece coating area is arranged between every two adjacent heat conduction sleeves. According to the utility model, the tab area of the pole piece is heated more uniformly, the extension uniformity of the tab area and the coating area is ensured, the pole piece is prevented from wrinkling, and meanwhile, the damage to the active material of the coating area is avoided. The lithium battery pole piece rolling device is suitable for the lithium battery pole piece rolling process.

Description

Technical Field

[0001] The utility model belongs to the technical field of pole piece rolling, in particular to a hot stretching device for a lithium battery pole piece rolling process. Background Art

[0002] Lithium-ion batteries have the advantages of high energy density, high open circuit voltage, long cycle life and environmental friendliness, and they occupy a pivotal position in the field of new energy. Pole sheet rolling is a necessary process in the manufacturing process of lithium-ion batteries. Lithium battery pole sheets refer to the positive and negative electrodes inside the battery. They are important components of lithium batteries. Usually, foil is used as the substrate. The foil is coated with active materials at intervals. The area coated with active materials is the coating area, and the area not coated with active materials is the lug area. Pole sheet rolling can enhance the bonding strength between the active material and the foil to prevent peeling during electrolyte immersion and battery use, and at the same time improve the energy density of lithium batteries. However, since the thickness of the coating area is much greater than that of the lug area, the coating area is stretched due to rolling during rolling, while the lug area is not stretched. This results in wrinkles or breaks in the lug area during the stretching process due to the different extension degrees between the coating area and the lug area.

[0003] A Chinese patent with application number 202111352848.7 discloses a segmented heating rolling mechanism and a pole piece rolling method. The above-mentioned segmented heating rolling mechanism includes relatively arranged working rollers, and a segmented heating assembly is arranged on the outer side of the working roller. When rolling the lithium battery pole pieces, the segmented heating assembly can perform segmented heating on the working roller along the axial direction, thereby changing the roller convexity of the corresponding heating area of ​​the working roller, so that the working roller can obtain precise roller convexity changes along the axial direction, and can adaptively perform precise heating and rolling on the lithium battery pole pieces, improve the thickness difference uniformity of the lithium battery pole pieces along the longitudinal direction, and ensure the quality of the produced lithium battery pole pieces. In the above-mentioned prior art disclosed, a segmented heating component is arranged on the outside of the working roller. When the pole piece is rolled, segmented heating is performed under the action of the segmented heating component, thereby changing the roller crown of the working roller, so that the pole piece is accurately heated and rolled. In this process, although the pole piece can be heated and rolled by the roller crown of the working roller, the heating temperature cannot be evenly distributed during the segmented heating process, so that the roller crown of the working roller cannot be accurately changed. At the same time, it cannot be ensured that the roller crown of the working roller is consistent with the thickness of the pole piece, so that the thickness difference uniformity of the pole piece cannot be guaranteed. Utility Model Content

[0004] The purpose of the utility model is to provide a thermal stretching device for the rolling process of lithium battery pole pieces, so as to make the heating of the pole piece ear area more uniform, ensure the uniformity of the extension of the pole ear area and the coating area, avoid wrinkles on the pole piece, and avoid damage to the active material in the coating area.

[0005] In order to achieve the above-mentioned purpose, the technical methods adopted by the utility model are as follows:

[0006] A heat stretching device for a lithium battery pole piece rolling process comprises an outer roller, an inner cylinder is installed inside the outer roller, the outer roller is coaxial with the inner cylinder, a heating mechanism is installed in the inner cavity of the inner cylinder, a plurality of heat conduction channels are evenly arranged circumferentially between the outer roller and the inner cylinder, the heat conduction channels are filled with a heat conduction fluid, both ends of the outer roller and the inner cylinder are sealed with shaft sleeves, and the other end of the shaft sleeve is fixedly connected with a rotating mechanism; a plurality of heat conduction sleeves for tightly pressing the pole piece ear area are sleeved on the outer roller, and a heat insulating sleeve for tightly pressing the pole piece coating area is provided between adjacent heat conduction sleeves.

[0007] As a limitation: a mounting groove is provided on one side of the heat-conducting sleeve close to the heat-insulating sleeve, and the heat-insulating sleeve is mounted on the mounting groove of the heat-conducting sleeve with a gap between the heat-insulating sleeve and the outer roller.

[0008] As a further limitation: a plurality of heat-conducting fluid channels are evenly arranged in the circumference of the rotating mechanism, a plurality of first channels for the heat-conducting fluid to pass through are evenly arranged in the circumference of the sleeve, the heat-conducting fluid channels are connected to the corresponding first channels, and the first channels are connected to the corresponding heat-conducting channels.

[0009] As a further limitation: a plurality of first cooling channels are evenly arranged circumferentially on the heat-conducting sleeve located at the edge, and a plurality of second cooling channels are evenly arranged circumferentially on the remaining heat-conducting sleeves, and both the first cooling channel and the second cooling channel are used for circulating cooling air, an opening at one end of the first cooling channel is arranged at the fitting surface of the corresponding heat-conducting sleeve and the outer roller, and the other end of the first cooling channel opens toward the gap between the insulating sleeve adjacent to the corresponding heat-conducting sleeve and the outer roller, and the openings at both ends of the second cooling channel respectively face the gap between the insulating sleeve adjacent to the corresponding heat-conducting sleeve and the outer roller; a plurality of cooling air channels are evenly arranged circumferentially on the inner circumference of the rotating mechanism, a plurality of second channels for cooling air to pass through are evenly arranged circumferentially on the inner circumference of the shaft sleeve, a plurality of third channels for cooling air to pass through are evenly arranged circumferentially between the outer roller and the inner cylinder, the cooling air channel is connected with the corresponding second channel, the second channel is connected with the corresponding third channel, and the third channel is connected with the corresponding first cooling channel.

[0010] As a further definition: a locking ring is provided at one end of the heat-conducting sleeve located at the edge close to the shaft sleeve, the locking ring is fixed on the outer roller, and a gap-eliminating spring is installed between the locking ring and the heat-conducting sleeve located at the edge.

[0011] As a further limitation: the rotating mechanism is a gas-liquid electric slip ring, the heat transfer fluid channel and the cooling air channel are arranged on the rotating ring of the gas-liquid electric slip ring, the rotating ring is fixedly connected to the shaft sleeve, a bearing is sleeved between the rotating ring and the shaft sleeve, and the bearing is installed on the bearing seat.

[0012] As a further limitation: the heating mechanism adopts one of electric heating, electromagnetic heating or heat medium heating.

[0013] Due to the adoption of the above solution, the utility model has the following beneficial effects compared with the prior art:

[0014] (1) The utility model provides a heat stretching device for a lithium battery pole piece rolling process, which provides a heat-conducting sleeve and a heat-insulating sleeve on an outer roller, and evenly provides a plurality of heat-conducting channels filled with a heat-conducting fluid between the outer roller and the inner roller in a circumferential direction, and utilizes the fluidity of the fluid to make the temperature of the outer roller surface more uniform, and the heating of the pole piece and the pole ear area more uniform; the pole piece and the pole ear area are heated evenly, and the heat-insulating sleeve isolates the heat of the outer roller, thereby ensuring the uniformity of the extension of the pole ear area and the coating area, avoiding wrinkles on the pole piece, and avoiding damage to the active material in the coating area;

[0015] (2) The utility model provides a heat stretching device for a lithium battery pole piece rolling process, which prevents the heat of the outer roller from being directly transferred to the heat insulating sleeve by installing the heat insulating sleeve on the mounting groove of the heat conductive sleeve and leaving a gap between the heat insulating sleeve and the outer roller, thereby further isolating the heat of the outer roller and avoiding damage to the active material in the coating area;

[0016] (3) The utility model provides a heat stretching device for a lithium battery pole piece rolling process, which provides a cooling channel for circulating cooling air on the heat conductive sleeve. When the outer roller needs to be cooled, the cooling air passes through the cooling air channel, the second channel and the third channel and enters the cooling channel, thereby achieving the purpose of cooling the outer roller;

[0017] (4) The utility model provides a heat stretching device for the rolling process of a lithium battery pole piece. By arranging a locking ring and a gap-eliminating spring, a gap is avoided between the heat-conducting sleeve and the heat-insulating sleeve due to different expansion coefficients. The gap-eliminating spring compensates for the gap by pre-compressing elastic deformation, so that the heat-conducting sleeve and the heat-insulating sleeve are tightly fitted axially, thereby avoiding damage to the pole piece.

[0018] The utility model is suitable for the rolling process of lithium battery pole pieces. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention is described in further detail below in conjunction with the accompanying drawings and specific embodiments.

[0020] Figure 1 This is a schematic cross-sectional structure diagram of a hot stretching device for a lithium battery pole piece rolling process according to an embodiment of the utility model;

[0021] In the figure: 1. outer roller; 2. inner cylinder; 3. bushing; 4. gas-liquid electric slip ring; 5. rotating ring; 6. bearing; 7. heat conduction channel; 8. first channel; 9. heat conduction fluid channel; 10. heat conduction sleeve; 11. insulation sleeve; 12. locking ring; 13. anti-backlash spring; 14. first cooling channel; 15. second cooling channel; 16. second channel; 17. third channel; 18. cooling air channel; 19. fixed shaft; 20. electromagnetic coil; 21. bearing seat. DETAILED DESCRIPTION

[0022] The present invention is further described below in conjunction with the embodiments. Those skilled in the art should understand that the present invention is not limited to the following embodiments, and any improvements and equivalent changes made based on the specific embodiments of the present invention are within the scope of protection of the claims of the present invention.

[0023] Embodiment A hot stretching device for a lithium battery pole piece rolling process

[0024] A hot stretching device for lithium battery pole piece rolling process, such as Figure 1As shown, it includes an outer roller 1, an inner cylinder 2 is installed inside the outer roller 1, the outer roller 1 and the inner cylinder 2 are coaxial, a heating mechanism is installed in the inner cavity of the inner cylinder 2, and a plurality of heat-conducting channels 7 are evenly arranged circumferentially between the outer roller 1 and the inner cylinder 2. The heat-conducting channels 7 are filled with heat-conducting fluid, and the fluidity of the fluid is used to make the roller surface temperature of the outer roller 1 more uniform; both ends of the outer roller 1 and the inner cylinder 2 are sealed and connected with a sleeve 3, and the other end of the sleeve 3 is fixedly connected with a rotating mechanism, and a plurality of heat-conducting fluid channels 9 are evenly arranged circumferentially in the rotating mechanism, and a plurality of first channels 8 for the heat-conducting fluid to pass through are evenly arranged in the sleeve 3. The heat-conducting fluid channels 9 are connected with the corresponding first channels 8, and the first channels 8 are connected with the corresponding heat-conducting channels 7. The heat-conducting fluid channel 9 in one rotating mechanism is used for the heat-conducting fluid to enter, and the heat-conducting fluid channel 9 in the other rotating mechanism is used for the heat-conducting fluid to be discharged. The outer roller 1 is provided with a plurality of heat-conducting sleeves 10 for tightly pressing the pole piece and the pole ear area, and a heat-insulating sleeve 11 for tightly pressing the pole piece coating area is provided between adjacent heat-conducting sleeves 10. The heat-conducting sleeve 10 is made of heat-conducting material, and the heat-insulating sleeve 11 is made of heat-insulating material. The pole ear area and the coating area of ​​the pole piece are separated by the heat-conducting sleeve 10 and the heat-insulating sleeve 11, and the pole ear area is heated to achieve hot stretching and stress release. A mounting groove is provided on the side of the heat-conducting sleeve 10 close to the heat-insulating sleeve 11, and the heat-insulating sleeve 11 is installed on the mounting groove of the heat-conducting sleeve 10 with a gap between the heat-insulating sleeve 11 and the outer roller 1, so as to prevent the heat of the outer roller 1 from being directly transferred to the heat-insulating sleeve 11, and prevent damage to the coating in the pole piece coating area; the diameter of the outer roller 1, the number and size of the heat-conducting sleeve 10 and the heat-insulating sleeve 11 can be arbitrarily designed and adjusted according to needs, and the heating temperature of the heating mechanism can be arbitrarily adjusted according to process requirements. A locking ring 12 is provided at one end of the heat-conducting sleeve 10 located at the edge close to the shaft sleeve 3. The locking ring 12 is fixed on the outer roller 1. A gap-eliminating spring 13 is installed between the locking ring 12 and the heat-conducting sleeve 10 located at the edge to avoid a gap between the heat-conducting sleeve 10 and the insulating sleeve 11, which is detrimental to the stretching of the pole piece.A plurality of first cooling channels 14 are evenly opened in the circumferential direction on the heat-conducting sleeve 10 located at the edge, and a plurality of second cooling channels 15 are evenly opened in the circumferential direction on the other heat-conducting sleeves 10. The first cooling channel 14 and the second cooling channel 15 are both used for circulating cooling air. One end opening of the first cooling channel 14 is arranged at the fitting surface of the corresponding heat-conducting sleeve 10 and the outer roller 1, and the other end opening of the first cooling channel 14 faces the gap between the insulating sleeve 11 adjacent to the corresponding heat-conducting sleeve 10 and the outer roller 1, and the two ends opening of the second cooling channel 15 face the gap between the insulating sleeve 11 adjacent to the corresponding heat-conducting sleeve 10 and the outer roller 1 respectively; the rotating mechanism A plurality of cooling air channels 18 are evenly arranged in the circumferential direction, a plurality of second channels 16 for cooling air to pass through are evenly arranged in the circumferential direction of the sleeve 3, a plurality of third channels 17 for cooling air to pass through are evenly arranged in the circumferential direction between the outer roller 1 and the inner cylinder 2, the cooling air channels 18 are connected with the corresponding second channels 16, the second channels 16 are connected with the corresponding third channels 17, the third channels 17 are connected with the corresponding first cooling channels 14, the cooling air channels 18 in one rotating mechanism are used for cooling air to enter, and the cooling air channels 18 in another rotating mechanism are used for cooling air to be discharged, and the heat conductive sleeve 10 can be quickly cooled by the cooling air.

[0025] In this embodiment, the rotating mechanism is a gas-liquid electric slip ring 4, and the heat-conducting fluid channel and the cooling air channel are arranged on the rotating ring 5 of the gas-liquid electric slip ring 4. The rotating ring 5 is fixedly connected to the shaft sleeve 3, and a bearing 6 is sleeved between the rotating ring 5 and the shaft sleeve 3. The bearing 6 is installed on the bearing seat 21; the heating mechanism adopts one of electric heating, electromagnetic heating or heat medium heating. The heating mechanism of this embodiment adopts electromagnetic heating. A fixed shaft 19 is provided in the inner cylinder 2, and the fixed shaft 19 is fixedly sleeved in the shaft sleeve 3. An electromagnetic coil 20 is wound around the fixed shaft 19.

[0026] The hot stretching device for the lithium battery pole piece rolling process of the present embodiment can handle pure aluminum pole pieces, copper pole pieces and composite current collectors, etc., can handle an elongation of 10%, reduce the requirements for the current collector, can process current collector materials with defects such as pinholes, can significantly reduce the pole piece running tension, can be used before or after rolling, or both before and after rolling, can be heated first and then stretched, or can be stretched first and then heated, and the number thereof can be set according to the specific process conditions, and one lithium battery pole piece rolling process hot stretching device can be set, or multiple lithium battery pole piece rolling process hot stretching devices can be set. When in use, the heating mechanism and the gas-liquid electric slip ring 4 are turned on, and the heat-conducting fluid is introduced into the heat-conducting channel 7 to heat the outer roller 1. The outer roller 1 transfers the heat to the heat-conducting sleeve 10, and the pole piece drives the hot stretching device of the lithium battery pole piece rolling process to rotate. The pole ear area of ​​the pole piece is rolled by the heat-conducting sleeve 10, and the coating area of ​​the pole piece is rolled by the insulation sleeve 11. The gap-eliminating spring 13 compensates for it by pre-compressing elastic deformation, so that the heat-conducting sleeve 10 and the insulation sleeve 11 are tightly fitted axially, avoiding damage to the pole piece caused by the gap between the heat-conducting sleeve 10 and the insulation sleeve 11 during the rolling process; when the temperature of the outer roller 1 is too high and needs to be cooled, the cooling air is introduced into the cooling channel to achieve the purpose of cooling the outer roller 1.

Claims

1. A hot stretching device for lithium battery pole piece rolling process, characterized in that: It includes an outer roller, an inner cylinder is installed inside the outer roller, the outer roller is coaxial with the inner cylinder, a heating mechanism is installed in the inner cavity of the inner cylinder, a plurality of heat-conducting channels are evenly arranged circumferentially between the outer roller and the inner cylinder, the heat-conducting channels are filled with heat-conducting fluid, both ends of the outer roller and the inner cylinder are sealed with shaft sleeves, and the other end of the shaft sleeve is fixedly connected with a rotating mechanism; a plurality of heat-conducting sleeves for tightly pressing the pole piece and the pole ear area are sleeved on the outer roller, and an insulating sleeve for tightly pressing the pole piece coating area is arranged between adjacent heat-conducting sleeves.

2. A hot stretching device for lithium battery pole piece rolling process according to claim 1, characterized in that: A mounting groove is arranged on one side of the heat-conducting sleeve close to the heat-insulating sleeve, and the heat-insulating sleeve is mounted on the mounting groove of the heat-conducting sleeve with a gap between the heat-insulating sleeve and the outer roller.

3. A hot stretching device for lithium battery pole piece rolling process according to claim 1 or 2, characterized in that: A plurality of heat-conducting fluid channels are evenly arranged in the circumference of the rotating mechanism, a plurality of first channels for the heat-conducting fluid to pass through are evenly arranged in the circumference of the sleeve, the heat-conducting fluid channels are connected with the corresponding first channels, and the first channels are connected with the corresponding heat-conducting channels.

4. A hot stretching device for lithium battery pole piece rolling process according to claim 2, characterized in that: A plurality of first cooling channels are evenly arranged circumferentially on the heat-conducting sleeve located at the edge, and a plurality of second cooling channels are evenly arranged circumferentially on the other heat-conducting sleeves. Both the first cooling channel and the second cooling channel are used for circulating cooling air. An opening at one end of the first cooling channel is arranged at the fitting surface of the corresponding heat-conducting sleeve and the outer roller, and an opening at the other end of the first cooling channel faces the gap between the insulating sleeve adjacent to the corresponding heat-conducting sleeve and the outer roller. Openings at both ends of the second cooling channel face the gap between the insulating sleeve adjacent to the corresponding heat-conducting sleeve and the outer roller respectively. A plurality of cooling air channels are evenly arranged circumferentially on the inner circumference of the rotating mechanism, a plurality of second channels for cooling air to pass through are evenly arranged circumferentially on the inner circumference of the shaft sleeve, and a plurality of third channels for cooling air to pass through are evenly arranged circumferentially between the outer roller and the inner cylinder. The cooling air channel is connected with the corresponding second channel, the second channel is connected with the corresponding third channel, and the third channel is connected with the corresponding first cooling channel.

5. A hot stretching device for lithium battery pole piece rolling process according to any one of claims 1, 2 and 4, characterized in that: A locking ring is provided at one end of the heat-conducting sleeve located at the edge close to the shaft sleeve. The locking ring is fixed on the outer roller, and a gap-eliminating spring is installed between the locking ring and the heat-conducting sleeve located at the edge.

6. A hot stretching device for lithium battery pole piece rolling process according to any one of claims 1, 2 and 4, characterized in that: The rotating mechanism is a gas-liquid electric slip ring, the heat transfer fluid channel and the cooling air channel are arranged on the rotating ring of the gas-liquid electric slip ring, the rotating ring is fixedly connected to the shaft sleeve, a bearing is sleeved between the rotating ring and the shaft sleeve, and the bearing is installed on the bearing seat.

7. A hot stretching device for lithium battery pole piece rolling process according to claim 3, characterized in that: The rotating mechanism is a gas-liquid electric slip ring, the heat transfer fluid channel and the cooling air channel are arranged on the rotating ring of the gas-liquid electric slip ring, the rotating ring is fixedly connected to the shaft sleeve, a bearing is sleeved between the rotating ring and the shaft sleeve, and the bearing is installed on the bearing seat.

8. A hot stretching device for lithium battery pole piece rolling process according to any one of claims 1, 2, 4 and 7, characterized in that: The heating mechanism adopts one of electric heating, electromagnetic heating or heat medium heating.

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