A winding process dynamic regulation system and method for ternary lithium batteries

Abstract

This invention relates to the field of battery cell technology, and particularly to a dynamic control system and method for the winding process of ternary lithium batteries. The system includes: pre-setting inner core winding parameters for layer-by-layer winding and hot-pressing composite; determining whether the initial tension exceeds the range, and adjusting the initial tension of each unwinding mechanism; calculating the current angle of the winding material at each unwinding mechanism based on the tangential force direction, and determining the relative relationship between the winding material and the winding needle by detecting the relative angle of the horizontal plate of the winding needle; determining whether global control is triggered based on the local pressure on the short axis and the local pressure on the long axis, correcting the tension change coefficient, and adjusting the unwinding speed; judging whether there is an angular deviation of the winding needle based on the current angle of the winding material at the negative electrode unwinding mechanism, adjusting the relative angle of the horizontal plate, and pre-adjusting the winding angular velocity for the next winding cycle; and adjusting the inner core winding parameters in real time based on the winding thickness. This invention produces a cell with a wrinkle-free inner layer through detection, analysis, and adjustment of the layer-by-layer winding and hot-pressing composite.

Description

Technical Field

[0001] This invention relates to the field of battery cell technology, and in particular to a dynamic control system and method for the winding process of ternary lithium batteries. Background Technology

[0002] Ternary lithium batteries, due to their high energy density and long cycle life, have become the mainstream choice in the power battery field. The manufacturing process of lithium battery cells is mainly divided into two methods: winding and stacking. Winded batteries, due to their mature production process, excel in applications requiring rapid charging and discharging and high cost-effectiveness. The related equipment and operating techniques are highly standardized, easily enabling automated production, and thus occupy an important position in ternary lithium battery manufacturing. The winding process involves winding pre-treated positive electrode sheets, separators, and negative electrode sheets in sequence using fixed winding needles. Specifically, the raw materials are stacked together in the order of negative electrode, separator, positive electrode, separator, and then directly wound into a cylindrical or elliptical cylinder, placed in a square or cylindrical metal casing. Compared to the stacking process, wound lithium batteries only have two electrodes, making production control relatively simple and welding easier. Furthermore, the winding process excels in improving battery consistency and reliability, offering high production efficiency and lower costs, giving it an advantage in large-scale production. Therefore, the cell winding process is one of the core links in cell manufacturing. The key lies in the uniformity of the winding material and the control of the winding tension, which directly affects the internal structure, performance, safety and energy density of the battery.

[0003] Chinese Patent Publication No. CN117303075A discloses a battery cell winding machine, winding method, and storage medium. The battery cell winding machine includes: a strip unwinding assembly, a tension balancing device, a winding device, an acceleration sensor, a tension measuring device, a memory, and a processor. The processor is used to call a computer program to execute the following steps: obtaining the first tension of the strip unwinding assembly; calculating the tension required to achieve acceleration of the strip; and, based on the total frictional resistance, the first tension, and the tension, controlling the tension balancing device to adaptively adjust the second tension applied to the strip, so that the tension on the strip is less than a preset threshold. The directions of the frictional force and the first tension are opposite to the conveying direction of the strip during winding, while the direction of the second tension is the same as the conveying direction of the strip during winding. Therefore, the battery cell winding machine, winding method, and storage medium have the following problems:

[0004] In the production process of existing wound lithium-ion batteries, wrinkles often appear on the inner negative electrode sheet after cell formation or capacity testing due to insufficient hot pressing or unreasonable tension settings during winding. Summary of the Invention

[0005] To address this issue, the present invention provides a dynamic control system and method for the winding process of ternary lithium batteries, which overcomes the problem of wrinkles in the inner negative electrode sheet of the battery cell caused by insufficient hot pressing and unreasonable tension settings during the winding process in the prior art.

[0006] To achieve the above objectives, the present invention provides a method for dynamic control of the winding process of ternary lithium batteries, comprising:

[0007] Pre-set inner core winding parameters for layer-by-layer hot-pressing composite winding;

[0008] Based on the actual tensile force of the fixed rotating roller of any unwinding mechanism, the initial tension borne by the corresponding roll material is quantified, and it is determined whether the initial tension exceeds the range of values. The unwinding speed of the corresponding unwinding mechanism is then adjusted accordingly.

[0009] The initial tension of each unwinding mechanism is varied according to the tension variation coefficient and the number of winding layers. The determination criteria for whether the initial tension of each unwinding mechanism exceeds the range after the tension variation is adjusted are as follows:

[0010] Calculate the current angle of the coil material in each unwinding mechanism based on the direction of the tangential force on the fixed rotating roller or support roller of each unwinding mechanism, and detect the relative angle of the transverse plate inside the coil needle.

[0011] The relative relationship between the roll and the horizontal plate is determined based on the current angle of the roll and the relative angle of the horizontal plate of any unwinding mechanism, and the tangent time of the corresponding roll to the major axis or minor axis of the winding needle is determined respectively.

[0012] Based on the tangent moment of the diaphragm unwinding mechanism, the local pressure of the short axis and the local pressure of the long axis of the winding needle at the corresponding moment are obtained respectively. Based on the local pressure of the short axis and the local pressure of the long axis, it is determined whether to trigger global control, correct the tension change coefficient, and adjust the unwinding speed of each unwinding mechanism.

[0013] The hot pressing node is determined according to the relative angle of the horizontal plate. Before hot pressing and bonding each inner core layer by layer, the angle deviation of the winding needle is judged according to the current angle of the material of the negative electrode unwinding mechanism. The relative angle of the horizontal plate is adjusted according to the angle deviation, and the winding angular speed of the next winding cycle is pre-adjusted.

[0014] The hot-pressing temperature parameter, hot-pressing pressure parameter, and winding needle temperature parameter in the inner core winding parameters are adjusted in real time according to the winding thickness.

[0015] Furthermore, the layer-by-layer winding hot-pressing composite process includes:

[0016] According to the inner core winding parameters, several layers of coaxially arranged inner cores are superimposed and wound on the winding needle. Each inner core includes a negative electrode sheet, a second separator, a positive electrode sheet and a first separator arranged sequentially from the outside to the inside.

[0017] For each inner core layer, the hot pressing device is controlled to heat and bond the outer wall side of the inner core layer, while the pressing device is controlled to heat the inner side of the inner core layer.

[0018] After the inner core is hot-pressed layer by layer, the hot pressing device and the winding needle are stopped from heating.

[0019] According to the preset cell winding parameters, several layers of coaxial outer winding cores are continued to be wound on the outermost inner winding core. Each outer winding core includes a negative electrode sheet, a second separator, a positive electrode sheet, and a first separator arranged sequentially from the outside to the inside. The winding is stopped after the preset winding parameters are met, and the initial cell is obtained.

[0020] The number of inner core winding layers is one-third of the number of battery cell winding layers.

[0021] Furthermore, the process of calculating the current angle of the coil in each unwinding mechanism based on the direction of the tangential force on the fixed rotating roller or support roller of each unwinding mechanism includes,

[0022] The current angle of the roll material in the diaphragm unwinding mechanism and the diaphragm unwinding mechanism is calculated based on the direction of the tangential force of the actual tension on the fixed rotating roller shaft at the center of the diaphragm unwinding mechanism and the diaphragm unwinding mechanism.

[0023] The current angle of the coil material in the positive electrode unwinding mechanism and the negative electrode unwinding mechanism is calculated based on the direction of the tangential force on the support rollers of the positive electrode unwinding mechanism and the negative electrode unwinding mechanism.

[0024] Furthermore, the current angle of the roll material of the diaphragm unwinding mechanism and the diaphragm unwinding mechanism is the angle formed by the roll material extending from the diaphragm unwinding mechanism and the diaphragm unwinding mechanism to the winding needle relative to the horizontal plane.

[0025] The current angle of the coil of the positive electrode unwinding mechanism and the negative electrode unwinding mechanism is the angle formed relative to the horizontal plane in the portion of the coil from the positive electrode unwinding mechanism and the negative electrode unwinding mechanism to the support roller and then to the winding needle.

[0026] Furthermore, the relative relationship between the coil and the coil needle is determined based on the current angle of the coil and the relative angle of the cross plate;

[0027] Calculate the angle difference between the current angle of the coil and the relative angle between the coil and the horizontal plate in the unwinding mechanism.

[0028] When the angle difference between the current angle of the coil and the relative angle of the cross plate in any unwinding mechanism is less than the standard deviation, it is determined that the cross plate is parallel to the coil of the corresponding unwinding mechanism.

[0029] If the difference between the current angle of the roll and the relative angle of the horizontal plate in any unwinding mechanism and the difference of 90 degrees is less than the standard deviation, it is determined that the horizontal plate is perpendicular to the roll of the corresponding unwinding mechanism.

[0030] Furthermore, when the horizontal plate is parallel to the roll of the corresponding unwinding mechanism, it is determined that the corresponding roll is tangent to the short axis of the winding needle, and the local pressure of the long axis of the winding needle at the corresponding moment is obtained.

[0031] When the horizontal plate is perpendicular to the roll of the corresponding unwinding mechanism, it is determined that the corresponding roll is tangent to the long axis of the winding needle, and the local pressure of the short axis of the winding needle at the corresponding moment is obtained.

[0032] Furthermore, global control is triggered based on the tension detection results of the diaphragm unwinding mechanism;

[0033] When the actual ratio of the local pressure on the short axis or the local pressure on the long axis to the corresponding standard pressure is not within the error range, it is determined that the initial tension borne by the corresponding roll material is not within the range of initial tension values.

[0034] If the initial tension is not within the initial tension value range, global control is triggered, the tension change coefficient is corrected, and the unwinding speed of each unwinding mechanism is adjusted accordingly.

[0035] Based on whether the actual ratio is lower or higher than the error range, the tension variation coefficient is reduced or increased, and the unwinding speed of the diaphragm unwinding mechanism and the other unwinding mechanisms is reduced or increased accordingly.

[0036] Furthermore, the hot pressing node is determined according to the relative angle of the horizontal plate. When the horizontal plate is rotated to the preset hot pressing angle, the hot pressing device is started to perform hot pressing according to the hot pressing parameters.

[0037] Before each layer of inner core is hot-pressed and laminated, the angle change value is calculated based on the current angle and historical angle of the roll of the negative electrode unwinding mechanism, and the angle change value is compared with the preset hot-pressing angle.

[0038] When the angle change value does not match the parameters in the reference table, it is determined that there is an angle deviation in the winding needle. The relative angle of the horizontal plate is adjusted according to the angle deviation, and the winding angular velocity of the winding needle is adjusted in advance during the braking phase of the next winding cycle.

[0039] Furthermore, the hot pressing pressure of the hot pressing device is positively correlated with the number of winding layers, the elastic modulus of the core material, and the core compressive strength coefficient;

[0040] The hot pressing temperature of the arc-shaped pressure plate is positively correlated with the number of winding layers and negatively correlated with the hot pressing surface area and the thermal conductivity of the core. The temperature of the winding needle is consistent with the hot pressing temperature of the arc-shaped pressure plate.

[0041] A dynamic control system for the winding process of a ternary lithium battery, comprising:

[0042] A winding device includes an unwinding mechanism, a winding needle, a hot pressing device, and a cutting device. The unwinding mechanism includes a positive electrode unwinding mechanism, a negative electrode unwinding mechanism, a diaphragm first unwinding mechanism, and a diaphragm second unwinding mechanism.

[0043] The diaphragm unwinding mechanism and the diaphragm unwinding mechanism unwind diaphragm one and diaphragm two according to the unwinding speed, and the roll extends from the diaphragm unwinding mechanism and the diaphragm unwinding mechanism to the winding needle;

[0044] The positive electrode unwinding mechanism and the negative electrode unwinding mechanism unwind the positive electrode and the negative electrode according to the unwinding speed. The rolled material extends from the positive electrode unwinding mechanism and the negative electrode unwinding mechanism to the support roller and then continues to the winding needle.

[0045] The winding needle has an elliptical hollow structure and a horizontal plate inside. The winding needle rotates according to the winding angular velocity to wind the roll material.

[0046] The hot pressing device is provided with an arc-shaped pressure plate at the top, which is used to hot press the inner core of the needle according to the hot pressing pressure and the hot pressing temperature at the hot pressing node;

[0047] Both the winding needle and the arc-shaped pressure plate are connected to the heating assembly for hot-pressing and heating the inner core wound on the winding needle.

[0048] Compared with existing technologies, the beneficial effects of this invention are that current methods for improving negative electrode wrinkles are difficult to operate in actual production, resulting in higher production costs and lower lithium-ion battery yield and production efficiency. In this invention, after obtaining each inner core layer, a hot-pressing device is controlled to heat and bond the outer wall of that inner core layer, while simultaneously controlling the winding needle to heat the inner core layer. The winding continues on the inner core layer until the preset conditions for cell winding parameters are met, after which the initial cell is cut to obtain the initial cell. It can fully release the stress between each layer of electrode and separator at the core, making the materials fit tightly together and improving the wrinkling problem after multiple layers of inner winding; it can improve the flatness of lithium-ion batteries, making the cell thickness meet the requirements and have high consistency; it can eliminate separator wrinkles, expel air inside the cell, and make the separator and positive and negative electrode sheets fit tightly together, shortening the lithium-ion diffusion distance and reducing the internal resistance of the battery; by cutting the separator and electrode sheets in layers, it can ensure the complete coverage of the separator. The core formed by this winding method has a tight spacing between the separator and electrode sheets, and between the electrode sheets, further reducing the risk of core wrinkling and improving the quality of lithium battery cells; the elliptical winding needle design can reduce the friction between the separator and the winding needle during winding, and optimize the winding needle profile through the elliptical curve equation to reduce electrode twisting and wrinkles.

[0049] Furthermore, this invention fully releases the stress between each layer of electrode and separator at the inner core by performing layer-by-layer hot-pressing composite winding of the separator, positive electrode sheet, and negative electrode sheet that make up the inner core, so that the superimposed materials are tightly bonded. At the same time, by detecting the tension on the fixed rotating roller bearing at the center of each unwinding mechanism, the tension borne by the positive electrode sheet, negative electrode sheet, separator one, and separator two is quantified. Based on the quantification results, the unwinding speed of each unwinding mechanism, i.e., the rotation speed of the fixed rotating roller shaft, is adjusted to further reduce the risk of core wrinkling and improve the quality of lithium battery cells, thereby improving the wrinkling problem after the inner layer of existing lithium batteries is wound.

[0050] Furthermore, during the winding process, tension control is crucial to ensuring a smooth cell interface and uniform interlayer bonding. Excessive tension fluctuations can cause the separator to be stretched during winding, thus placing high demands on tension control. In the tension control process of the coil, the radius of curvature of the cell increases with the increase in the number of winding layers. This increased radius of curvature leads to a corresponding increase in the initial tension borne by the positive electrode, negative electrode, separator one, and separator two. This invention uses different tension coefficients to vary the initial tension borne by different coils and adjusts the unwinding speed of the corresponding unwinding mechanism based on the real-time tension changes to ensure constant / variable tension of the coil during winding. The evaluation criteria for actual tension are adjusted accordingly to prevent excessive stretching caused by the continuous increase in the radius of curvature of the coil, thereby increasing the stability and adaptability of tension control for different coils.

[0051] Furthermore, since the radius of curvature of the winding is larger on the major axis side of the ellipse, the tension needs to be appropriately reduced to avoid stretching and deformation of the electrode. The rotation speed needs to be reduced to avoid electrode accumulation or tearing. The radius of curvature of the minor axis side of the ellipse is smaller, so the tension needs to be increased to prevent the electrode from loosening and causing wrinkles. The winding needle speed can be increased to maintain a relatively constant linear speed.

[0052] Furthermore, since the winding needle is elliptical, the angle of the coiled material changes periodically during the rotation of the winding needle. In the unwinding mechanism, the coiled material of the diaphragm one and diaphragm two unwinding mechanisms extends directly from the unwinding mechanism to the winding needle, while the coiled material of the positive and negative electrode unwinding mechanisms extends to the winding needle under the directional adjustment of the support roller shaft. Combining the above characteristics, this method calculates the current angle of the coiled material in each unwinding mechanism based on the direction of the tangential force on the fixed rotating roller shaft and the support roller shaft, increasing the adaptability to the coiling device and the accuracy and anti-interference of the subsequent determination of relative relationships. Furthermore, based on the determined relative relationship, the secondary quantification of the local pressure of the short axis / long axis of the winding needle corresponds to the tension magnitude borne by the coiled material, verifying whether the tension of the coiled material falls within the set initial tension value range. This method is not affected by the increase in the core radius, the elliptical shape of the winding needle, or the relative position of each unwinding mechanism, and can minimize the complexity of tension verification.

[0053] Furthermore, this invention determines the relative relationship between the roll and the winding needle by the current angle of the roll and the relative angle of the cross plate, determines whether the minor axis or major axis of the corresponding roll and the winding needle are tangent, and adopts a corresponding detection strategy to quantify whether the tension of the corresponding roll under the current state falls within the normal range of the determined initial tension based on the local pressure borne by the winding needle. Since the diaphragm one is relatively earlier in the winding cycle, the global control is triggered based on the tension detection result of the diaphragm one unwinding mechanism to correct the tension change coefficient and the unwinding speed of the unwinding mechanism. This can play a predictive role to reduce the tension influence on the roll of the subsequent unwinding mechanism, and increase the flexibility and accuracy of tension control.

[0054] Furthermore, since the layer-by-layer winding hot-pressing composite has start-stop requirements within the winding cycle corresponding to each inner core layer, the hot pressing needs to match the angle of the inner core layer. In this invention, the preset hot pressing angle is constant, while the angle of the unwinding mechanism of the diaphragm changes continuously due to the influence of radius and ellipse. Combining the hot pressing angle with the angle change value of the negative electrode sheet roll material that varies with the core thickness, the horizontal plate is checked for angle deviation before hot pressing to prevent errors in the process of determining the hot pressing node based on the relative angle of the horizontal plate. This ensures that the winding needle stops at the relative angle of the horizontal plate that matches the arc-shaped pressure plate before hot pressing.

[0055] Furthermore, the present invention adjusts the hot pressing temperature and pressure parameters of the hot pressing device and the temperature parameters of the winding needle in real time according to the winding thickness of the core. The parameters change automatically with the number of winding layers. For each additional inner core layer, the hot pressing temperature and pressure of the arc-shaped pressure plate are increased, keeping the hot pressing process under reasonable hot pressing temperature and pressure, thereby increasing the control accuracy of layer-by-layer winding hot pressing composite during the core winding process.

[0056] Furthermore, this invention utilizes an arc-shaped pressure plate to perform layer-by-layer hot-pressing composite of the inner core and heats the inner core using a coiling needle. This fully releases the stress between each electrode and separator layer in the inner core, eliminating wrinkles and winding stress in the negative electrode during winding. This results in a tighter fit between the stacked materials, improving the wrinkling problem after inner layer winding in existing lithium batteries. It avoids the problem of poor wetting that may be caused by excessive hot pressing of the first electrode layer due to repeated hot pressing. The hot pressing pressure, temperature of the coiling needle and the arc-shaped pressure plate, and winding tension are dynamically adjusted according to the number of winding layers; this avoids insufficient hot pressing and unreasonable tension settings during winding, preventing excessive expansion of the electrode during formation; reducing dead zones and lithium plating caused by core wrinkles, reducing voltage polarization, and increasing cell safety performance; and reducing the distance between the separator and electrode, and between electrode layers, reducing electrolyte consumption and improving cycle performance. Attached Figure Description

[0057] Figure 1 This is a flowchart of the dynamic control system and method for the winding process of a ternary lithium battery in an embodiment of the present invention.

[0058] Figure 2 This is a schematic diagram of the winding device for a ternary lithium battery cell in an embodiment of the present invention;

[0059] Figure 3 This is a flowchart illustrating the determination of the relative relationship between the roll material and the winding needle in an embodiment of the present invention;

[0060] Figure 4 This is a flowchart illustrating how to determine whether the initial tension exceeds the range of values ​​in an embodiment of the present invention.

[0061] In the figure: 1-unwinding mechanism, 10-diaphragm unwinding mechanism 1, 11-diaphragm unwinding mechanism 2, 12-positive electrode unwinding mechanism, 13-negative electrode unwinding mechanism, 2-winding needle, 21-horizontal plate, 3-hot pressing device, 31-arc pressure plate, 4-cutting device, 5-support roller shaft. Detailed Implementation

[0062] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0063] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0064] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0065] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0066] Please see Figures 1-4 As shown, Figure 1 This is a flowchart of the method for dynamic control of the winding process of ternary lithium batteries in an embodiment of the present invention; Figure 2 This is a schematic diagram of the winding device for a ternary lithium battery cell in an embodiment of the present invention; Figure 3 This is a flowchart illustrating the determination of the relative relationship between the roll material and the winding needle in an embodiment of the present invention; Figure 4 This is a flowchart illustrating how to determine whether the initial tension exceeds the range of values ​​in an embodiment of the present invention.

[0067] This invention provides a method for dynamically controlling the winding process of ternary lithium batteries, comprising:

[0068] Step S1: Preset the inner core winding parameters and perform layer-by-layer winding and hot-pressing composite.

[0069] Step S2: Based on the actual tensile force of the fixed rotating roller shaft of any unwinding mechanism, the initial tension borne by the corresponding roll material is calculated, and it is determined whether the initial tension exceeds the range of values. The unwinding speed of the corresponding unwinding mechanism is adjusted accordingly.

[0070] Step S3: Adjust the initial tension of each unwinding mechanism according to the tension change coefficient and the number of winding layers, and determine whether the initial tension of each unwinding mechanism exceeds the range after adjusting the tension change.

[0071] Step S4: Calculate the current angle of the roll material of each unwinding mechanism based on the direction of the tangential force on the fixed rotating roller or support roller of each unwinding mechanism, and detect the relative angle of the transverse plate inside the winding needle.

[0072] Step S5: Determine the relative relationship between the roll and the horizontal plate based on the current angle of the roll and the relative angle of the horizontal plate of any unwinding mechanism, and determine the tangent time of the corresponding roll and the major axis or minor axis of the winding needle respectively.

[0073] Step S6: Based on the tangent time of the diaphragm unwinding mechanism, obtain the local pressure of the short axis and the local pressure of the long axis of the winding needle at the corresponding time. Determine whether to trigger global control based on the local pressure of the short axis and the local pressure of the long axis, correct the tension change coefficient, and adjust the unwinding speed of each unwinding mechanism.

[0074] Step S7: Determine the hot pressing node according to the relative angle of the horizontal plate. Before hot pressing and bonding any inner core layer by layer, determine whether there is an angle deviation of the winding needle according to the current angle of the material of the negative electrode unwinding mechanism. Adjust the relative angle of the horizontal plate according to the angle deviation and pre-adjust the winding angular velocity of the next winding cycle.

[0075] Step S8: Adjust the hot pressing temperature parameter, hot pressing pressure parameter, and winding needle temperature parameter in the inner core winding parameters in real time according to the winding thickness.

[0076] The layer-by-layer winding and hot-pressing composite process includes:

[0077] Step S11: According to the preset inner core winding parameters, several layers of coaxially arranged inner cores are superimposed and wound on the winding needle. Each inner core includes a negative electrode sheet, a second separator, a positive electrode sheet, and a first separator arranged sequentially from the outside to the inside.

[0078] In step S12, after obtaining each inner core layer, the hot pressing device is controlled to heat and bond the outer wall side of the inner core layer; at the same time, the roll is controlled to heat the inner core layer to obtain an inner core layer without wrinkles.

[0079] Step S13: After the inner core is hot-pressed and laminated layer by layer, control the hot pressing device and the winding needle to stop heating.

[0080] Step S14: According to the preset cell winding parameters, several layers of coaxial outer winding cores are continued to be wound on the outermost inner winding core. Each outer winding core includes a negative electrode sheet, a second separator, a positive electrode sheet, and a first separator arranged sequentially from the outside to the inside. The winding is stopped after the preset winding parameters are met, and the initial cell is obtained.

[0081] Step S15: After undergoing a preset post-processing procedure, the initial battery cell is formed into a battery cell with no wrinkles in the inner layer.

[0082] The number of inner core winding layers is one-third of the number of battery cell winding layers.

[0083] Specifically, current methods for improving negative electrode wrinkles are difficult to implement in actual production, resulting in higher production costs and lower lithium-ion battery yield and production efficiency. This invention, after obtaining each inner core layer, controls a hot-pressing device to heat and bond the outer wall of that inner core layer while simultaneously heating the inner core layer with a winding needle. The winding continues on the inner core layer until the preset cell winding parameters are met, at which point it is cut to obtain the initial cell. It can fully release the stress between each layer of electrode and separator at the core, making the materials fit tightly together and improving the wrinkling problem after multiple layers of inner winding; it can improve the flatness of lithium-ion batteries, making the cell thickness meet the requirements and have high consistency; it can eliminate separator wrinkles, expel air inside the cell, and make the separator and positive and negative electrode sheets fit tightly together, shortening the lithium-ion diffusion distance and reducing the internal resistance of the battery; by cutting the separator and electrode sheets in layers, it can ensure the complete coverage of the separator. The core formed by this winding method has a tight spacing between the separator and electrode sheets, and between the electrode sheets, further reducing the risk of core wrinkling and improving the quality of lithium battery cells; the elliptical winding needle design can reduce the friction between the separator and the winding needle during winding, and optimize the winding needle profile through the elliptical curve equation to reduce electrode twisting and wrinkles.

[0084] The process of setting the preset inner core winding parameters includes:

[0085] Set the initial parameters for diaphragm one, positive electrode sheet, diaphragm two, and negative electrode sheet on the unwinding mechanism and winding needle. The initial parameters include the initial tension and the tension variation coefficient.

[0086] The winding parameters of the winding device are set, including the number of inner core winding layers, the number of battery cell winding layers, the hot pressing temperature parameters and hot pressing pressure parameters of the hot pressing device, and the temperature parameters of the winding needle.

[0087] The tension borne by the positive electrode, negative electrode, diaphragm one, and diaphragm two is quantified by detecting the tension on the fixed rotating roller bearing at the center of each unwinding mechanism. The unwinding speed of each unwinding mechanism, i.e., the rotational speed of the fixed rotating roller shaft, is adjusted according to the quantification results.

[0088] The actual tension on several fixed rotating roller bearings in the unwinding mechanism is detected in real time and compared with the corresponding standard tension. The fixed rotating rollers of the positive electrode unwinding mechanism, negative electrode unwinding mechanism, diaphragm one unwinding mechanism and diaphragm two unwinding mechanism correspond to different standard tensions.

[0089] If the actual difference between the actual tension of any unwinding mechanism and its corresponding standard tension is greater than the difference evaluation value, it is determined that the tension borne by the corresponding roll exceeds the value range, and the unwinding speed of the corresponding unwinding mechanism is adjusted.

[0090] Specifically, the ratio of the actual difference to the standard tension is used as the variation range to adjust the unwinding speed of the unwinding mechanism;

[0091] When the actual tension of any unwinding mechanism is greater than its corresponding standard tension, the unwinding speed of the corresponding unwinding mechanism is increased according to the change range.

[0092] When the actual tension of any unwinding mechanism is less than its corresponding standard tension, the unwinding speed of the corresponding unwinding mechanism shall be reduced according to the change range.

[0093] The difference evaluation value is positively correlated with the standard tensile force, and the difference evaluation value is equal to 1.5% of the standard tensile force. The material roll includes a positive electrode sheet, a negative electrode sheet, a separator one, and a separator two.

[0094] The standard tension is a preset value set based on historical tension data corresponding to the initial tension of several unwinding mechanisms.

[0095] In this embodiment, the unwinding linear speed of any unwinding mechanism is equal to the winding linear speed of the winding needle.

[0096] Specifically, this invention involves layer-by-layer hot-pressing and bonding of the separator, positive electrode sheet, and negative electrode sheet that make up the inner core, thereby fully releasing the stress between each layer of electrode sheet and separator in the inner core, resulting in a tight fit between the stacked materials. At the same time, by detecting the tension on the fixed rotating roller bearing at the center of each unwinding mechanism, the tension borne by the positive electrode sheet, negative electrode sheet, separator one, and separator two is quantified. Based on the quantification results, the unwinding speed of each unwinding mechanism, i.e., the rotational speed of the fixed rotating roller shaft, is adjusted to further reduce the risk of core wrinkling and improve the quality of lithium battery cells, thereby improving the wrinkling problem after the inner layer is wound in existing lithium batteries.

[0097] During the tension control process of the coil, since the initial tension borne by the positive electrode, negative electrode, separator one and separator two increases with the number of winding layers, the initial tension is changed according to the tension change coefficient, and the standard tension is corresponding to the change of the initial tension.

[0098] The initial tension of the positive electrode is set to M, and the initial tension of the negative electrode is set to N, with M = N; the initial tension of membrane one and the initial tension of membrane two are both L.

[0099] The tension variation coefficients of diaphragm 1 and diaphragm 2 are both X, the tension variation coefficient of the positive electrode is Y, and the tension variation coefficient of the negative electrode is Z, and |Z|≥|Y|>3|X|;

[0100] The initial tension varies with the number of winding layers and the tension variation coefficient. The expression for the dynamically changing tension is: ΔM=M+Y×n;

[0101] In the formula, ΔM is the dynamically changing tension, and n is the number of winding layers.

[0102] The initial tension values ​​of the positive electrode, negative electrode, separator one, and separator two are respectively 1500g > M > 1000g, 1500g > N > 1000g, and 500g > L > 300g.

[0103] The tension variation coefficients of the first diaphragm, the second diaphragm, the positive electrode, and the negative electrode are respectively -5 > X > -6, -25 > Y > -35, -25 > Z > -35, and Y = Z.

[0104] The initial tension varies with the number of winding layers and the tension variation coefficient. The unwinding speed of the corresponding unwinding mechanism is increased according to the initial tension of the roll, thereby reducing the tension borne by the corresponding roll.

[0105] Specifically, tension control is crucial for ensuring a smooth cell interface and uniform interlayer bonding during the winding process. Excessive tension fluctuations can cause the separator to be stretched during winding, thus placing high demands on tension control. During the tension control of the coil, the radius of curvature of the cell increases with the number of winding layers. This increased radius of curvature leads to a corresponding increase in the initial tension borne by the positive electrode, negative electrode, separator one, and separator two. This invention addresses this by setting different tension coefficients to vary the initial tension borne by different coils. Based on the real-time changes in initial tension, the unwinding speed of the corresponding unwinding mechanism is adjusted to ensure constant / variable tension of the coil during winding. The evaluation criteria for actual tension are also adjusted accordingly, preventing excessive stretching caused by the continuous increase in the radius of curvature of the coil. This increases the stability and adaptability of tension control for different coils.

[0106] In this embodiment, the winding needle in the winding device has an elliptical hollow structure, and a horizontal plate is provided inside the winding needle;

[0107] When the horizontal plate is parallel to the roll of material of each unwinding mechanism, it means that the corresponding roll of material is tangent to the short axis of the winding needle; when the horizontal plate is perpendicular to the roll of material of each unwinding mechanism, it means that the corresponding roll of material is tangent to the long axis of the winding needle.

[0108] When the corresponding roll material is tangent to the short axis of the winding needle, it is the moment when the tension change of the corresponding roll material is the greatest during the corresponding winding cycle.

[0109] When the corresponding roll material is tangent to the long axis of the winding needle, it is the moment when the tension change of the corresponding roll material is the smallest in the corresponding winding cycle.

[0110] The relative angle between the horizontal plate and the horizontal plane is detected in real time, as well as the current angle of the roll of material in each unwinding mechanism.

[0111] The process of detecting the current angle of the roll material in the diaphragm unwinding mechanism and the diaphragm unwinding mechanism includes calculating the current angle of the roll material based on the tangential force direction of the actual tension force on the fixed rotating roller shaft at the center of the diaphragm unwinding mechanism and the diaphragm unwinding mechanism.

[0112] The process of detecting the current angle of the coil material of the positive electrode unwinding mechanism and the negative electrode unwinding mechanism includes calculating the current angle of the coil material based on the direction of the tangential force on the support roller shaft of the positive electrode unwinding mechanism and the negative electrode unwinding mechanism.

[0113] The relative relationship between the coil and the coil needle is determined based on the current angle of the coil and the relative angle of the cross plate.

[0114] In this embodiment, the winding angular velocity of the winding needle is adjusted in real time according to the elliptical curvature, and the winding linear velocity of the winding needle is relatively constant.

[0115] In practice, the radius of curvature is smallest when the short axis is tangent, so the winding angular velocity of the winding needle is increased to compensate for the winding linear velocity and keep the winding linear velocity relatively constant; the radius of curvature is largest when the long axis is tangent, so the winding angular velocity of the winding needle is reduced to avoid material stretching.

[0116] Specifically, on the major axis side of the ellipse, due to the larger radius of curvature of the winding, the tension needs to be appropriately reduced to avoid stretching and deformation of the electrode, and the rotation speed needs to be reduced to avoid electrode accumulation or tearing. On the minor axis side of the ellipse, due to the smaller radius of curvature, the tension needs to be increased to prevent the electrode from loosening and causing wrinkles, and the winding needle speed can be increased to maintain a relatively constant linear speed.

[0117] Meanwhile, since the present invention adopts a layer-by-layer winding hot-pressing composite method, each layer of core corresponds to a winding cycle. The winding needle starts to rotate and stops rotating within any winding cycle. The angle of the roll material corresponding to each unwinding mechanism changes periodically during the rotation of the winding needle.

[0118] The relative relationship between the coil and the winding needle is determined based on the current angle of the coil and the relative angle of the horizontal plate, and the angle difference between the current angle of the coil and the relative angle of the horizontal plate of the unwinding mechanism is calculated.

[0119] When the angle difference between the current angle of the coil and the relative angle of the cross plate in any unwinding mechanism is less than the standard deviation, it is determined that the cross plate is parallel to the coil of the corresponding unwinding mechanism.

[0120] When the difference between the current angle of the coil and the relative angle of the horizontal plate in any unwinding mechanism and the difference of 90 degrees is less than the standard deviation, it is determined that the horizontal plate is perpendicular to the coil of the corresponding unwinding mechanism.

[0121] When the horizontal plate is parallel to the roll of the corresponding unwinding mechanism, it is determined that the corresponding roll is tangent to the short axis of the winding needle, and the local pressure of the long axis of the winding needle at the corresponding moment is obtained.

[0122] When the horizontal plate is perpendicular to the roll of the corresponding unwinding mechanism, it is determined that the corresponding roll is tangent to the long axis of the winding needle, and the local pressure of the short axis of the winding needle at the corresponding moment is obtained.

[0123] Specifically, the local pressure on the needle is measured by pressure sensors placed at the four corners of the needle winding.

[0124] The local pressure on the short axis and the local pressure on the long axis, which are obtained according to the relative relationship between the roll and the winding needle of the diaphragm unwinding mechanism, are detected.

[0125] When the actual ratio of the local pressure on the short axis or the local pressure on the long axis to the corresponding standard pressure is not within the error range, it is determined that the initial tension borne by the corresponding roll is not within the initial tension value range, triggering global control, correcting the tension change coefficient, and adjusting the unwinding speed of each unwinding mechanism accordingly.

[0126] Specifically, when the actual ratio exceeds the error range, the tension change coefficient is multiplied by the actual ratio to increase the tension change coefficient, and the unwinding speed of the diaphragm unwinding mechanism and the other unwinding mechanisms is increased accordingly.

[0127] When the actual ratio is lower than the error range, the tension change coefficient is multiplied by the actual ratio to reduce the tension change coefficient, and the unwinding speed of the diaphragm unwinding mechanism and the other unwinding mechanisms is reduced accordingly.

[0128] Since the diaphragm one is relatively early in the winding cycle, the global control is triggered based on the tension detection results of the diaphragm one unwinding mechanism. This adjusts the tension change coefficient and the unwinding speed of the unwinding mechanism, which can play a predictive role and reduce the tension impact on the subsequent unwinding mechanism, thereby increasing the flexibility and accuracy of tension control.

[0129] The standard pressure is a preset value set based on historical local pressure data corresponding to the initial tension, and the error range is 98%-102%.

[0130] Specifically, since the winding needle is elliptical, the angle of the coiled material changes periodically during the rotation of the winding needle. In the unwinding mechanism, the coiled material of the diaphragm one and diaphragm two unwinding mechanisms extends directly from the unwinding mechanism to the winding needle, while the coiled material of the positive and negative electrode unwinding mechanisms extends to the winding needle under the directional adjustment of the support roller shaft. Combining the above characteristics, this method calculates the current angle of the coiled material in each unwinding mechanism based on the direction of the tangential force on the fixed rotating roller shaft and the support roller shaft, increasing the adaptability to the coiling device and the accuracy and anti-interference of the subsequent determination of relative relationships. Furthermore, based on the determined relative relationship, the local pressure of the short axis / long axis of the winding needle is obtained by secondary quantification to correspond to the tension of the coiled material, and the tension of the coiled material is checked to see if it falls within the set initial tension value range. This method is not affected by the increase of the core radius, the elliptical shape of the winding needle, or the relative position of each unwinding mechanism, and can minimize the complexity of tension testing.

[0131] This invention determines the relative relationship between the roll and the winding needle by using the current angle of the roll and the relative angle of the cross plate. It determines whether the minor axis or major axis of the corresponding roll is tangent to the winding needle. A corresponding detection strategy is adopted to quantify whether the tension of the corresponding roll under the current state falls within the normal range of the determined initial tension based on the local pressure borne by the winding needle. Since the diaphragm is relatively early in the winding cycle, global control is triggered based on the tension detection results of the diaphragm unwinding mechanism to correct the tension change coefficient and the unwinding speed of the unwinding mechanism. This can play a predictive role and reduce the tension impact on the roll of the subsequent unwinding mechanism, thereby increasing the flexibility and accuracy of tension control.

[0132] The hot pressing node is determined according to the relative angle of the horizontal plate. When the horizontal plate is rotated to the preset hot pressing angle, the hot pressing device is started to perform hot pressing according to the hot pressing parameters.

[0133] Before each layer of inner core is hot-pressed and laminated, the angle change value is calculated based on the current angle and historical angle of the roll of the negative electrode unwinding mechanism, and the angle change value is compared with the preset hot-pressing angle.

[0134] When the angle change value does not match the parameters in the reference table, it is determined that there is an angle deviation in the winding needle. The relative angle of the horizontal plate is adjusted according to the angle deviation, and the winding angular velocity of the winding needle is adjusted in advance during the braking phase of the next winding cycle.

[0135] Wherein, the historical angle of the roll material is the stored data of the current angle of the roll material detected, and the comparison table parameter is a preset table set according to the historical data of the comparison between the current angle of the roll material of the negative electrode unwinding mechanism and the preset hot pressing angle under the current number of winding layers of each inner core.

[0136] Specifically, since the layer-by-layer winding hot-pressing composite has start-stop requirements within the winding cycle corresponding to each inner core layer, the hot pressing needs to match the angle of the inner core layer. In this invention, the preset hot pressing angle is constant, while the angle of the unwinding mechanism of the diaphragm changes continuously due to the influence of radius and ellipse. Combining the hot pressing angle with the angle change value of the negative electrode sheet roll material that varies with the core thickness, the horizontal plate is checked for angle deviation before hot pressing to prevent errors in the process of determining the hot pressing node based on the relative angle of the horizontal plate. This ensures that the winding needle stops at the relative angle of the horizontal plate that matches the arc-shaped pressure plate before hot pressing.

[0137] The hot pressing temperature and pressure parameters of the hot pressing device, as well as the temperature parameters of the winding needle, change automatically with the number of winding layers. For each additional inner core layer, the hot pressing temperature and pressure of the arc-shaped pressure plate are automatically adjusted upwards. This is used to adjust the appropriate hot pressing temperature and pressure in real time according to the winding thickness, and the temperature of the winding needle is always consistent with the hot pressing temperature of the arc-shaped pressure plate.

[0138] The formula for calculating hot-pressing pressure is:

[0139] F = (q × (2δ membrane + δ positive electrode + δ negative electrode)) × (2 × S × E);

[0140] In the formula, δdiaphragm, δpositive, and δnegative represent the thickness of the diaphragm, positive electrode, and negative electrode, respectively; S represents the core compressive strength coefficient; E represents the elastic modulus of the core material; F represents the hot-pressing pressure of the arc-shaped pressure plate; and q represents the number of inner core layers.

[0141] The core compressive strength coefficient is a parameter that reflects the core structure's ability to resist deformation under pressure. It characterizes the additional resistance of the core's interlayer structure (such as a diaphragm, positive and negative electrode stacks, or winding structure) under external pressure due to factors such as material friction and interlayer bonding.

[0142] When the core is subjected to hot pressure, slippage or micro-displacement may occur between the layers. S corrects the theoretical pressure value by quantifying this structural effect. If the core layers are tightly bonded (such as in high-tension winding), the S value may be higher, indicating that greater pressure (F) is required to achieve the same compression effect; conversely, a loose structure will have a lower S value.

[0143] The value of S is usually obtained through experimental calibration: the deviation between the actual hot-pressing pressure and the theoretical value (the calculated value when S is ignored) is measured, and the value of S is deduced. For example, if the measured pressure is 1.5 times the theoretical value, then S can be approximated as 0.75;

[0144] Example: Suppose that the calculated pressure of a battery core is 100N without considering S, but in reality 150N needs to be applied to achieve the target thickness. In the corrected formula, S≈0.75 (because 2×S×E needs to produce a 1.5 times compensation effect).

[0145] The hot pressing temperature T of the arc-shaped pressure plate is related to the thickness of the battery cell winding and the relevant physical properties of the battery cell;

[0146] The formula for calculating the hot-pressing temperature is as follows:

[0147] T = (W × q × (2δ membrane + δ positive electrode + δ negative electrode)) / (K × A) + T0;

[0148] In the formula, W represents the power output of the hot press, K represents the thermal conductivity of the core, A represents the hot pressing surface area, T0 represents the room temperature, T represents the hot pressing temperature of the arc-shaped pressure plate, and q represents the number of inner core layers.

[0149] Specifically, this invention adjusts the hot pressing temperature and pressure parameters of the hot pressing device and the temperature parameters of the winding needle in real time according to the winding thickness of the core. The parameters change automatically with the number of winding layers. For each additional inner core layer, the hot pressing temperature and pressure of the arc-shaped pressure plate are increased, keeping the hot pressing process under reasonable hot pressing temperature and pressure, thereby increasing the control accuracy of layer-by-layer winding hot pressing composite during the core winding process.

[0150] A dynamic control system for the winding process of a ternary lithium battery, comprising a winding device;

[0151] The winding device includes an unwinding mechanism 1, a winding needle 2, a hot pressing device 3, and a cutting device 4. The unwinding mechanism 1 includes a positive electrode unwinding mechanism 12, a negative electrode unwinding mechanism 13, a diaphragm first unwinding mechanism 10, and a diaphragm second unwinding mechanism 11.

[0152] The diaphragm unwinding mechanism and the diaphragm unwinding mechanism unwind diaphragm one and diaphragm two according to the unwinding speed, and the roll extends from the diaphragm unwinding mechanism and the diaphragm unwinding mechanism to the winding needle;

[0153] The positive electrode unwinding mechanism and the negative electrode unwinding mechanism unwind the positive electrode and the negative electrode according to the unwinding speed. The rolled material extends from the positive electrode unwinding mechanism and the negative electrode unwinding mechanism to the support roller and then continues to the winding needle.

[0154] The winding needle 2 has an elliptical hollow structure, and a horizontal plate 21 is provided inside the winding needle 2. The winding needle rotates according to the winding angular velocity to wind the roll material.

[0155] The hot pressing device 3 has an arc-shaped pressure plate 31 at its top, which is used to hot press the inner core of the winding needle at the hot pressing node according to the hot pressing pressure and the hot pressing temperature. The unwinding mechanism 1 has a fixed rotating roller shaft in the center.

[0156] The aforementioned winding needle 2 and arc-shaped pressure plate 31 are both connected to the heating assembly and are used to perform hot pressing and heating on the inner core wound on the winding needle 2.

[0157] After the inner core is hot-pressed layer by layer to the preset number of inner core winding layers, the hot-pressing of the arc-shaped pressure plate and the heating of the winding needle are stopped to obtain an inner core without wrinkles.

[0158] Specifically, this invention utilizes an arc-shaped pressure plate to perform layer-by-layer hot-pressing composite of the inner core and a heating device to heat the inner core, fully releasing the stress between each electrode and separator layer in the inner core. This eliminates wrinkles and winding stress in the negative electrode during winding, resulting in a tighter fit between the stacked materials and improving the wrinkling problem after inner layer winding in existing lithium batteries. It avoids the problem of poor wetting that may be caused by excessive hot pressing of the first electrode layer due to repeated hot pressing. The hot pressing pressure, temperature of the heating needle and arc-shaped pressure plate, and winding tension are dynamically adjusted according to the number of winding layers; this avoids insufficient hot pressing and unreasonable tension settings during winding, preventing excessive expansion of the electrode during formation; reducing dead zones and lithium plating caused by core wrinkles, reducing voltage polarization, and increasing cell safety performance; and reducing the distance between the separator and electrode, and between electrode pieces, reducing electrolyte consumption and improving cycle performance.

[0159] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

[0160] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for dynamically controlling the winding process of a ternary lithium battery, characterized in that, include: Pre-set inner core winding parameters for layer-by-layer hot-pressing composite winding; Based on the actual tensile force of the fixed rotating roller of any unwinding mechanism, the initial tension borne by the corresponding roll material is quantified, and it is determined whether the initial tension exceeds the range of values. The unwinding speed of the corresponding unwinding mechanism is then adjusted accordingly. The initial tension of each unwinding mechanism is varied according to the tension variation coefficient and the number of winding layers. The determination criteria for whether the initial tension of each unwinding mechanism exceeds the range after the tension variation is adjusted are as follows: Calculate the current angle of the coil material in each unwinding mechanism based on the direction of the tangential force on the fixed rotating roller or support roller of each unwinding mechanism, and detect the relative angle of the transverse plate inside the coil needle. The relative relationship between the roll and the horizontal plate is determined based on the current angle of the roll and the relative angle of the horizontal plate of any unwinding mechanism. The angle difference between the current angle of the roll and the relative angle of the horizontal plate of the unwinding mechanism is calculated, and the tangent time between the corresponding roll and the major axis or minor axis of the winding needle is determined respectively. When the angle difference between the current angle of the unwinding mechanism of the diaphragm and the relative angle of the horizontal plate is less than the standard deviation, it is determined that the horizontal plate is parallel to the unwinding mechanism of the corresponding unwinding mechanism, and the corresponding unwinding mechanism of the ... When the difference between the current angle of the unwinding mechanism of the diaphragm and the relative angle of the horizontal plate is less than the standard deviation of 90 degrees, it is determined that the horizontal plate is perpendicular to the unwinding mechanism of the corresponding unwinding mechanism, and the corresponding unwinding mechanism of the ... Based on the local pressure on the short axis and the local pressure on the long axis, determine whether to trigger global control, correct the tension change coefficient, and adjust the unwinding speed of each unwinding mechanism; The hot pressing node is determined according to the relative angle of the horizontal plate. Before hot pressing and bonding each inner core layer by layer, the angle deviation of the winding needle is judged according to the current angle of the material of the negative electrode unwinding mechanism. The relative angle of the horizontal plate is adjusted according to the angle deviation, and the winding angular speed of the next winding cycle is pre-adjusted. The hot-pressing temperature parameter, hot-pressing pressure parameter, and winding needle temperature parameter in the inner core winding parameters are adjusted in real time according to the winding thickness.

2. The method for dynamic control of the winding process of a ternary lithium battery according to claim 1, characterized in that, The layer-by-layer winding and hot-pressing composite process includes: According to the inner core winding parameters, several layers of coaxially arranged inner cores are superimposed and wound on the winding needle. Each inner core includes a negative electrode sheet, a second separator, a positive electrode sheet and a first separator arranged sequentially from the outside to the inside. For each inner core layer, the hot pressing device is controlled to heat and bond the outer wall side of the inner core layer, while the pressing device is controlled to heat the inner side of the inner core layer. After the inner core is hot-pressed layer by layer, the hot pressing device and the winding needle are stopped from heating. According to the preset cell winding parameters, several layers of coaxial outer winding cores are continued to be wound on the outermost inner winding core. Each outer winding core includes a negative electrode sheet, a second separator, a positive electrode sheet, and a first separator arranged sequentially from the outside to the inside. The winding is stopped after the preset winding parameters are met, and the initial cell is obtained. The number of inner core winding layers is one-third of the number of battery cell winding layers.

3. The method for dynamic control of the winding process of a ternary lithium battery according to claim 1, characterized in that, The process of calculating the current angle of the coil in each unwinding mechanism based on the direction of the tangential force on the fixed rotating roller or support roller of each unwinding mechanism includes: The current angle of the roll material in the diaphragm unwinding mechanism and the diaphragm unwinding mechanism is calculated based on the direction of the tangential force of the actual tension on the fixed rotating roller shaft at the center of the diaphragm unwinding mechanism and the diaphragm unwinding mechanism. The current angle of the coil material in the positive electrode unwinding mechanism and the negative electrode unwinding mechanism is calculated based on the direction of the tangential force on the support rollers of the positive electrode unwinding mechanism and the negative electrode unwinding mechanism.

4. The method for dynamic control of the winding process of a ternary lithium battery according to claim 3, characterized in that, The current angle of the roll material of the diaphragm unwinding mechanism and the diaphragm unwinding mechanism is the angle formed by the roll material extending from the diaphragm unwinding mechanism and the diaphragm unwinding mechanism to the winding needle relative to the horizontal plane. The current angle of the coil of the positive electrode unwinding mechanism and the negative electrode unwinding mechanism is the angle formed relative to the horizontal plane in the portion of the coil from the positive electrode unwinding mechanism and the negative electrode unwinding mechanism to the support roller and then to the winding needle.

5. The method for dynamic control of the winding process of a ternary lithium battery according to claim 1, characterized in that, Global control is triggered based on the tension detection results of the diaphragm unwinding mechanism; When the actual ratio of the local pressure on the short axis or the local pressure on the long axis to the corresponding standard pressure is not within the error range, it is determined that the initial tension borne by the corresponding roll material is not within the range of initial tension values. If the initial tension is not within the initial tension value range, global control is triggered, the tension change coefficient is corrected, and the unwinding speed of each unwinding mechanism is adjusted accordingly. Based on whether the actual ratio is lower or higher than the error range, the tension variation coefficient is reduced or increased, and the unwinding speed of the diaphragm unwinding mechanism and the other unwinding mechanisms is reduced or increased accordingly.

6. The method for dynamic control of the winding process of a ternary lithium battery according to claim 1, characterized in that, The hot pressing node is determined according to the relative angle of the horizontal plate. When the horizontal plate is rotated to the preset hot pressing angle, the hot pressing device is started to perform hot pressing according to the hot pressing parameters. Before each layer of inner core is hot-pressed and laminated, the angle change value is calculated based on the current angle and historical angle of the roll of the negative electrode unwinding mechanism, and the angle change value is compared with the preset hot-pressing angle. When the angle change value does not match the parameters in the reference table, it is determined that there is an angle deviation in the winding needle. The relative angle of the horizontal plate is adjusted according to the angle deviation, and the winding angular velocity of the winding needle is adjusted in advance during the braking phase of the next winding cycle.

7. The method for dynamic control of the winding process of a ternary lithium battery according to claim 1, characterized in that, The hot pressing pressure of the hot pressing device is positively correlated with the number of winding layers, the elastic modulus of the core material, and the core compressive strength coefficient. The hot pressing temperature of the arc-shaped pressure plate is positively correlated with the number of winding layers and negatively correlated with the hot pressing surface area and the thermal conductivity of the core. The temperature of the winding needle is equal to the hot pressing temperature of the arc-shaped pressure plate.

8. A control system for the dynamic control method of the winding process of a ternary lithium battery according to any one of claims 1-7, characterized in that, include: A winding device includes an unwinding mechanism, a winding needle, a hot pressing device, and a cutting device. The unwinding mechanism includes a positive electrode unwinding mechanism, a negative electrode unwinding mechanism, a diaphragm first unwinding mechanism, and a diaphragm second unwinding mechanism. The diaphragm unwinding mechanism and the diaphragm unwinding mechanism unwind diaphragm one and diaphragm two according to the unwinding speed, and the roll extends from the diaphragm unwinding mechanism and the diaphragm unwinding mechanism to the winding needle; The positive electrode unwinding mechanism and the negative electrode unwinding mechanism unwind the positive electrode and the negative electrode according to the unwinding speed. The rolled material extends from the positive electrode unwinding mechanism and the negative electrode unwinding mechanism to the support roller and then continues to the winding needle. The winding needle has an elliptical hollow structure and a horizontal plate inside. The winding needle rotates according to the winding angular velocity to wind the roll material. The hot pressing device is provided with an arc-shaped pressure plate at the top, which is used to hot press the inner core of the needle according to the hot pressing pressure and the hot pressing temperature at the hot pressing node; Both the winding needle and the arc-shaped pressure plate are connected to the heating assembly for hot-pressing and heating the inner core wound on the winding needle.

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