Hollow composite roller and rolling system
By designing the sandwiched oil tank and branch oil pipeline of the hollow composite roller, and combining it with sensor-based pressure adjustment, the problems of decarburization and uneven thickness in the intermittent coating area during the rolling process were solved, achieving uniform rolling and efficient production of the electrode sheets.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- XINGTAI HAI YU LITHIUM BATTERY EQUIP LTD
- Filing Date
- 2025-04-08
- Publication Date
- 2026-04-21
AI Technical Summary
In existing roll forming processes, local stress concentration in intermittent coating areas can easily lead to decarburization. Traditional solid rollers can easily cause electrode elastic recovery, resulting in thickness fluctuations and uneven porosity. Furthermore, it is difficult to achieve coordinated control of temperature and pressure, which affects battery energy density and cycle life.
A hollow composite roller is used, with an oil chamber between the roller core and the roller sleeve. The heat transfer oil in the chamber can be adjusted in pressure and temperature, and the heat transfer oil is evenly distributed through branch oil pipelines to increase the contact area and contact time. Combined with sensors to adjust the pressure in real time, the rolling process is dynamically controlled.
It improves the lateral thickness uniformity of the electrode, reduces rebound and decarburization, enhances the mechanical strength and conductivity of the electrode, extends the roll life, and reduces maintenance costs.
Smart Images
Figure CN224143169U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of electrode rolling technology, and relates to a hollow composite roller and rolling system. Background Technology
[0002] Roll forming is one of the core processes in lithium-ion battery electrode manufacturing. Two high-precision rollers apply pressure to the coated electrode, ensuring tight adhesion between the active material and the current collector, while simultaneously adjusting the electrode thickness and porosity. This process induces plastic deformation of the active particles through mechanical compression, reducing interfacial contact resistance and improving the electrode's conductivity and mechanical strength, directly impacting the battery's energy density, cycle life, and rate performance. In intermittent coating processes, roll forming must also consider the transition between coated and uncoated areas. It must ensure uniform compaction density in the coated area while avoiding abnormal stress distribution in the uncoated area caused by structural abrupt changes. This places stringent requirements on roller deformation control, pressure transmission efficiency, and temperature field uniformity.
[0003] Current roll forming processes face multiple technical challenges: First, the uncoated areas of intermittently coated electrodes, lacking an active material layer for buffering, are prone to localized stress concentration under roll pressure, leading to the detachment of active material at the end of the intermittent section, resulting in decarburization and damaging the integrity of the electrode structure. Second, traditional solid rolls, due to rigid contact, easily induce elastic recovery of the electrode, causing thickness fluctuations and uneven porosity distribution, indirectly reducing the consistency of battery energy density. Third, existing equipment struggles to achieve coordinated temperature and pressure control during dynamic roll forming—excessive temperature accelerates binder softening, exacerbating the risk of decarburization; insufficient temperature necessitates increased pressure, inducing rebound. This strong coupling of process parameters causes decarburization and rebound problems to overlap, becoming a common challenge restricting the manufacturing of high-energy-density batteries. Summary of the Invention
[0004] The purpose of this utility model is to provide a hollow composite roller that can adjust the pressure and temperature inside the roller during rolling and increase the contact area between the electrode sheet and the roller surface, thereby improving the lateral thickness consistency of the electrode sheet after rolling and reducing the rebound of the electrode sheet after rolling.
[0005] The second objective of this invention is to provide a rolling system comprising the aforementioned hollow composite roller, which can dynamically adjust the pressure on the electrode during rolling according to the longitudinal coating thickness distribution of the electrode, thereby improving the decarburization problem of the electrode.
[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows:
[0007] A hollow composite roller includes a roller core and a roller sleeve fitted over the roller core;
[0008] A jacketed oil tank for containing heat-conducting oil is provided between the roller core and the roller sleeve;
[0009] A main oil pipe is provided inside the roller core along the length of the roller core, and the opening of the main oil pipe is located at one end of the roller core;
[0010] At least one branch oil pipeline connecting the main oil pipeline and the interlayer oil tank is provided between the main oil pipeline and the interlayer oil tank.
[0011] As a limitation, the main oil pipeline is located on the central axis of the roller core.
[0012] As a further limitation, the branch oil line is perpendicular to the central axis of the roller core.
[0013] As a second limitation, when the number of branch oil lines is greater than one, the branch oil lines are evenly distributed along the length direction of the roller core.
[0014] As a third limitation, the surface of the roller sleeve is provided with a metal plating layer.
[0015] As a further limitation, the metal coating is a chromium plating layer.
[0016] As a fourth limitation, the thickness of the roller sleeve is 5mm-300mm, and the volume ratio of heat transfer oil in the central control composite roller is 1%-80%.
[0017] As a fifth limitation, the temperature of the heat transfer oil is controlled between 5℃ and 100℃.
[0018] A rolling system includes, in addition to two hollow composite rollers as described above, two hydraulic pumps respectively connected to the opening of the main oil pipeline of the hollow composite rollers, two temperature controllers for controlling the temperature of the heat transfer oil, and two sensors for detecting whether there is active material on the surface of the electrode sheet.
[0019] The two hollow composite rollers are respectively disposed above and below the electrode sheet, and are clamped to the electrode sheet;
[0020] The two sensors are respectively located above and below the electrode sheet to be pressed, and the output terminals of the two sensors are respectively connected to the hydraulic pump control terminal of the hollow composite roller at the corresponding position.
[0021] The technological advancements achieved by this invention compared to existing technologies, due to the adoption of the aforementioned technical solution, are as follows:
[0022] (1) The hollow composite roller of this utility model has an interlayer oil tank between the roller core and the roller sleeve, so that an elastic interlayer is formed between the roller sleeve and the roller core. On the one hand, it increases the contact area between the hollow composite roller and the electrode during rolling, which prolongs the time the electrode is pressed in the roller gap, makes the rolling pressure distribution in the transverse direction of the electrode more uniform, and makes the plastic deformation of the active material particles more sufficient, reducing the elastic deformation of the electrode after rolling and improving the transverse thickness deviation of the electrode. On the other hand, the buffering effect of the elastic interlayer can disperse the local pressure peak, avoid microcracks or non-uniform compression caused by stress concentration in the material, thereby reducing the rebound caused by subsequent stress release.
[0023] (2) The hollow composite roller of this utility model can reduce the temperature difference between the roller and the electrode through the heat-conducting oil in the jacket oil tank, which can effectively reduce the interfacial stress between the active material and the current collector, improve the material ductility, and improve the effect of electrode roller pressing.
[0024] (3) The branch oil pipelines in the hollow composite roller of this utility model are evenly distributed along the length of the roller core, which can make the heat transfer oil achieve a more balanced flow distribution and pressure transmission along the length of the roller core, ensuring the stability of the temperature field and stress field of the roller surface, reducing the defects such as uneven thickness and damage of active material caused by local overheating or pressure deviation of the electrode during the rolling process, and enhancing the system's dynamic compensation capability for roller core deformation.
[0025] (4) In the hollow composite roller of this utility model, the roller sleeve surface is provided with a chromium plating layer, which can significantly improve the surface hardness and wear resistance, reduce wear and micro-cracks caused by high pressure friction, thereby extending the roller life; the heat resistance of the chromium plating layer adapts to the local temperature rise during the rolling process; in addition, the smooth surface of the chromium plating layer can reduce the frictional resistance between the electrode and the roller surface, reduce the risk of coating damage, and improve the flatness of the electrode surface after rolling.
[0026] (5) The hollow composite roller of this utility model adopts a separate design of roller core and roller sleeve. After the roller sleeve is severely worn, only the outer part needs to be replaced, avoiding the scrapping of the entire roller and significantly reducing maintenance costs and resource waste.
[0027] (6) The roller pressing system of this utility model detects the state of the intermittently coated electrode in real time through a sensor and dynamically adjusts the pressure of the heat transfer oil in the interlayer oil tank. It can accurately control the contact pressure distribution between the roller surface and the electrode, reduce the local pressure peak at the intermittent position, and thus avoid electrode wrinkling, cracking or active material peeling.
[0028] This invention belongs to the field of electrode rolling technology. It can adjust the temperature during rolling and increase the contact area between the electrode and the roller surface, improve the lateral thickness consistency of the electrode after rolling, and reduce the rebound of the electrode after rolling. Attached Figure Description
[0029] The accompanying drawings are provided to further understand the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention and do not constitute a limitation thereof.
[0030] In the attached diagram:
[0031] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present utility model;
[0032] Figure 2 for Figure 1 Sectional view of section AA;
[0033] Figure 3 for Figure 1 Sectional view of section BB;
[0034] Figure 4 for Figure 1 A sectional view of section C-C;
[0035] Figure 5 A comparison diagram of the indentation width of a conventional roller of the same diameter and Embodiment 1 of this utility model under the same linear pressure;
[0036] Figure 6 A comparison diagram of the thickness rebound of the electrode sheet after rolling with a conventional roller and according to Embodiment 1 of this utility model;
[0037] Figure 7 This is a diagram showing the transverse thickness distribution of the electrode sheet after being rolled by a conventional roller.
[0038] Figure 8 This is a diagram showing the transverse thickness distribution of the electrode sheet after rolling in Embodiment 1 of this utility model;
[0039] Figure 9 This is a structural block diagram of Embodiment 2 of the present invention;
[0040] Figure 10 Images showing the intermittent positions of the electrode sheets after ordinary roller pressing;
[0041] Figure 11 This is a picture of the intermittent position of the electrode sheet after rolling in Embodiment 2 of this utility model.
[0042] In the diagram: 1. Roller sleeve, 2. Roller core, 3. Main oil pipeline, 4. Jacketed oil tank, 5. Branch oil pipeline. Detailed Implementation
[0043] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.
[0044] Example 1: A hollow composite roller
[0045] like Figures 1 to 4 As shown, this embodiment is a hollow composite roller, including a roller core 2 and a roller sleeve 1 sleeved outside the roller core 2. A jacketed oil tank 4 for placing heat transfer oil is provided between the roller core 2 and the roller sleeve 1.
[0046] To ensure the flow of heat transfer oil within the jacketed oil tank 4, a main oil pipeline 3 with an opening at one end of the roller core 2 is provided on the central axis of the roller core 2. Twelve branch oil pipelines 5 connect the main oil pipeline 3 and the jacketed oil tank 4. The heat transfer oil is distributed within the jacketed oil tank 4, the branch oil pipelines 5, and the main oil pipeline 3.
[0047] The twelve branch oil pipes 5 are evenly distributed along the length of the roller core 2, all perpendicular to the central axis of the roller core 2, and every two adjacent branch oil pipes 5 are perpendicular to each other.
[0048] To prevent the heat transfer oil in the jacketed oil tank 4 from leaking out from the connection between the roller core 2 and the roller sleeve 1, the connection between the roller core 2 and the roller sleeve 1 is welded together.
[0049] To improve the surface hardness and wear resistance of roller sleeve 1, a chromium plating layer is applied to the surface of roller sleeve 1.
[0050] In this embodiment, the thickness of the roller sleeve 1 is 250mm, and the volume ratio of heat transfer oil in the central control composite roller is 14.5%. In this embodiment, the temperature of the heat transfer oil is fixed at 60℃ during use, and the interlayer oil tank 4 is located between the roller core 2 and the roller sleeve 1, playing an elastic buffering role.
[0051] The comparison chart shows the indentation width of a standard roller (8585 type roller press) with a diameter of 800mm and the indentation width of a roller press in this embodiment, both operating at an online pressure of 0.5t / cm. Figure 5 As shown, by Figure 5 It can be seen that the indentation width of a regular roller is 1.2 mm, while the indentation width of this embodiment is 2.2 mm. This shows that in this embodiment, the contact area between the surface of the roller sleeve 1 and the electrode sheet is increased during roller pressing, which prolongs the pressure time of the electrode sheet in the roller gap, and thus the indentation width is also wider.
[0052] To highlight the improvement in electrode rebound in this embodiment, the thickness of the middle region of the electrode after rolling was measured and compared between ordinary rollers (8585 type roller press) and those of this embodiment. The results are as follows: Figure 6 As shown. From Figure 6 It can be seen that this embodiment can effectively improve the thickness rebound of the electrode sheet after rolling.
[0053] To highlight the improvement in the lateral thickness consistency of the electrode sheet in this embodiment, the lateral thickness data of the electrode sheet at 8 seconds after exiting the roll were measured using a laser thickness gauge, both with a conventional roll (8585 type roll press) and with that of this embodiment. The results are as follows: Figure 7 and Figure 8 As shown. By comparison Figure 7 and Figure 8 It can be seen that this embodiment can effectively improve the lateral thickness consistency of the electrode sheet after rolling.
[0054] It should be noted that in this embodiment, the thickness of the roller sleeve 1 is 250mm, the volume ratio of the heat transfer oil in the central control composite roller is 14.5%, and the temperature of the heat transfer oil is set to 60℃. All of the above data can be changed according to the actual situation, as long as the thickness of the roller sleeve 1 is 5mm-300mm, the volume ratio of the heat transfer oil in the central control composite roller is 1%-80%, and the temperature of the heat transfer oil is 5℃-100℃.
[0055] In this embodiment, the main oil pipeline 3 is located on the central axis of the roller core 2. However, the position of the main oil pipeline 3 can be changed according to actual conditions and is not limited to the central axis of the roller core 2. The surface coating of the roller sleeve 1 is a chromium plating layer, which can be adjusted to other plating layers according to actual conditions, as long as the rolling process requirements are met.
[0056] In addition, in this embodiment, there are twelve branch oil lines 5. The number can be changed according to the actual situation of the roller core 2, as long as it meets the process parameter requirements during rolling. In this embodiment, the connection between the roller core 2 and the roller sleeve 1 is welded together. Alternatively, it can be changed to a sealing method of sealing gasket plus metal cap, as long as the connection does not leak heat transfer oil.
[0057] Example 2: A roller pressing system
[0058] like Figure 9 As shown, this embodiment includes two hollow composite rollers as described in Embodiment 1. The two hollow composite rollers are respectively disposed above and below the electrode sheet, and are clamped to the electrode sheet. A hydraulic pump and a temperature controller are connected to the opening of the main oil pipeline 3 of each hollow composite roller. The hydraulic pump drives the flow of heat transfer oil inside the hollow composite roller, and the temperature controller is used to control the temperature of the heat transfer oil.
[0059] A sensor for detecting the state of the electrode sheet is installed above and below the sheet to be pressed. The output terminals of the two sensors are connected to the hydraulic pump control terminals of the corresponding hollow composite rollers. The sensor model is Omron E3C-LD11N 2M.
[0060] In this embodiment, two sensors monitor the surface condition of the electrode in real time and transmit the corresponding signals to the hydraulic pump. The hydraulic pump dynamically adjusts the pressure of the heat transfer oil, thereby affecting the pressure on the electrode during rolling. When the sensors detect an uncoated area on the electrode, the hydraulic pump reduces the pressure of the heat transfer oil to 30% of the pressure value of the normal rolling coating area.
[0061] A comparison diagram of the electrode interval positions after rolling with that of a conventional roller and that of this embodiment is shown below. Figure 10 and Figure 11 As shown in the figure, it can be seen that after the electrode is rolled by a regular roller, it suffers severe decarburization at the intermittent positions; while after the electrode is rolled by the roller in this embodiment, it does not suffer decarburization at the intermittent positions.
[0062] It should be noted that in this embodiment, when the sensor detects an uncoated area on the electrode, the pressure of the hydraulic pump will be reduced to 30%. The reduction value can be changed according to the actual situation, as long as the reduced pressure value is 2%-80% of the normal value.
[0063] In summary, this embodiment utilizes dynamic hydraulic pressure control and temperature regulation technology of the hollow roller body to precisely optimize the pressure distribution and roller profile changes in multi-interface regions. This proactively increases the longitudinal contact length between the electrode and the roller surface during rolling, weakening the hard impact caused by sudden thickness changes at the junction of intermittent electrode sheets during rolling, effectively solving the decarburization problem in the junction area. Furthermore, the increased longitudinal contact width between the roller surface and the electrode indirectly increases the rolling time and significantly suppresses the rebound of intermittently and continuously coated electrode sheets.
Claims
1. A hollow composite roll characterized by, Includes the roller core and the roller sleeve fitted over the roller core; A jacketed oil tank for containing heat-conducting oil is provided between the roller core and the roller sleeve; A main oil pipe is provided inside the roller core along the length of the roller core, and the opening of the main oil pipe is located at one end of the roller core; At least one branch oil pipeline connecting the main oil pipeline and the interlayer oil tank is provided between the main oil pipeline and the interlayer oil tank.
2. A hollow composite roll according to claim 1, characterized in that The main oil pipeline is located on the central axis of the roller core.
3. A hollow composite roll according to claim 2, wherein The branch oil pipeline is perpendicular to the central axis of the roller core.
4. A hollow composite roll according to any one of claims 1 to 3, characterized in that When the number of branch oil lines is greater than one, the branch oil lines are evenly distributed along the length direction of the roller core.
5. The hollow composite roll of claim 1 wherein, The roller sleeve surface is provided with a metal plating layer.
6. A hollow composite roll as claimed in claim 5, wherein, The metal plating is a chromium plating layer.
7. The hollow composite roll of claim 1 wherein, The thickness of the roller sleeve is 5mm-300mm, and the volume ratio of heat transfer oil in the central control composite roller is 1%-80%.
8. The hollow composite roll of claim 1 wherein, The temperature of the heat transfer oil is controlled between 5℃ and 100℃.
9. A roller pressing system, characterized in that, In addition to including two hollow composite rollers as described in any one of claims 1 to 8, it also includes two hydraulic pumps respectively connected to the opening of the main oil pipeline of the hollow composite roller, two temperature controllers for controlling the temperature of the heat transfer oil, and two sensors for detecting whether there is active material on the surface of the electrode sheet. The two hollow composite rollers are respectively disposed above and below the electrode sheet, and are clamped to the electrode sheet; The two sensors are respectively located above and below the electrode sheet to be pressed, and the output terminals of the two sensors are respectively connected to the hydraulic pump control terminal of the hollow composite roller at the corresponding position.