A pole coil and a control method of cooling the pole coil

Abstract

The application discloses a pole piece and a control method for cooling the pole piece. The pole piece comprises a pole piece, the deformation radius of the pole piece is 1.5-3.5 mm / m, the moisture content is 85-105 ppm, and the wrinkle defect rate is 0.3%-0.7%. The control method for cooling the pole piece is executed by a control component and comprises the following steps: introducing a cooling medium into a target chamber provided with the pole piece; acquiring a real-time temperature signal of a first temperature sensor beside the pole piece; and dynamically adjusting the supply intensity of the cooling medium to the target chamber according to the real-time temperature signal and preset cooling strategy parameters, wherein the preset cooling strategy parameters are limited to limit the cooling rate in an initial high-temperature stage and to increase the cooling rate in a subsequent low-temperature stage. The above product effectively releases the internal thermal stress of the pole piece, fully discharges the water vapor and is uniform in structure by quantitatively characterizing the physical parameters, and solves the problems of deformation and moisture content rebound caused by the quenching process; and the cooling intensity is dynamically controlled by using real-time temperature closed-loop feedback.

Description

Technical Field

[0001] This application relates to the field of electrode cooling technology, specifically to an electrode and a method for controlling the cooling electrode. Background Technology

[0002] In the lithium battery electrode winding and baking process, the electrode needs to be baked to fully remove internal moisture and residual solvents, and then cooled to obtain the electrode roll product. The physical properties of the electrode roll product are directly related to the cycle life, gas expansion risk and safety performance of the downstream battery cell. Therefore, the electrode roll product needs to have good appearance quality and stable physical and chemical properties.

[0003] In related technologies, the cooling method after electrode baking typically involves using a constant, high-volume, ambient-temperature cold airflow to rapidly cool the oven cavity and the electrode. This process is open-loop controlled, relying on fixed time intervals and not on temperature feedback for phased adjustments. Under this direct cooling method, a significant temperature difference occurs between the surface and interior of the high-temperature electrode, and between the inner and outer rings of the electrode roll. Uneven thermal expansion and contraction causes internal stress in the electrode, easily leading to defects such as warping, wrinkles, and micro-deformation. Simultaneously, rapid cooling causes the electrode pores to shrink instantaneously, trapping residual moisture inside and causing a rebound in moisture content. Therefore, electrode rolls produced using this technology typically exhibit electrode deformation curvature of 3-4 mm / m, moisture content of 100-115 ppm, and a wrinkle defect rate of 0.6%-1%, exhibiting significant internal stress deformation and unstable moisture content.

[0004] The aforementioned defects make it difficult for electrode rolls used as raw materials in battery cell manufacturing to meet requirements for electrode structure uniformity, moisture control precision, and batch consistency. This increases the risk of cell gas expansion, self-discharge, and decreased capacity and internal resistance consistency. Therefore, obtaining an electrode roll product with smaller deformation curvature, lower moisture content, and lower wrinkle defect rate has become an urgent technical problem to be solved in this field. Summary of the Invention

[0005] In view of this, this application provides an electrode roll that at least solves the problems of large electrode deformation curvature, high electrode moisture content, and high electrode wrinkling defect rate caused by poor electrode roll cooling. This application also provides a method for controlling the cooling of the electrode roll.

[0006] To achieve the above objectives, this application provides the following technical solution: An electrode roll, comprising an electrode sheet, wherein the electrode sheet has a deformation curvature of 1.5-3.5 mm / m, a moisture content of 85-105 ppm, and a wrinkle defect rate of 0.3%-0.7%.

[0007] A method for controlling the cooling of an electrode roll, wherein the method is executed by a control unit and includes the following steps: S001: Control the cooling system to introduce cooling medium into the target chamber where the pole rolls are installed; S002: A first temperature sensor is provided on the side of the electrode roll to obtain the real-time temperature signal of the first temperature sensor; S003: Based on the real-time temperature signal and preset cooling strategy parameters, dynamically adjust the intensity of the cooling medium supplied by the cooling system to the target chamber; The preset cooling strategy parameters are defined as follows: limiting the cooling rate during the initial high-temperature phase measured by the first temperature sensor, and increasing the cooling rate during the subsequent low-temperature phase measured by the first temperature sensor.

[0008] Optionally, the preset cooling strategy is segmented cooling, including: When the first temperature sensor is in a first stage where it is greater than the first target temperature T1, the controller controls the cooling system to supply the cooling medium to the target chamber at the T1 temperature and a rate of t1℃ / min; when the first temperature sensor is in a second stage where it is less than or equal to T1 and greater than the second target temperature T2, the controller controls the cooling system to supply the cooling medium to the target chamber at the T2 temperature and a rate of t2℃ / min; when the first temperature sensor is in a third stage where it is less than or equal to T2 and greater than the third target temperature T3, the controller controls the cooling system to supply the cooling medium to the target chamber at the T3 temperature and a rate of t3℃ / min. Wherein, t1, t2 and t3 satisfy: t1 < t2 < t3.

[0009] Optionally, in the first stage, the cooling rate is monitored in real time. If the cooling rate is detected to exceed the set value, the heating power is automatically compensated and / or the air intake volume is reduced.

[0010] Optionally, in the second stage, the actual cooling curve is compared with the preset standard curve in real time, and the wind pressure parameters are dynamically adjusted according to the comparison results.

[0011] Optionally, the third stage is initiated after the real-time temperature drops to a preset low-temperature safety threshold, and during this stage, the pole roll is cooled at the maximum rate under conditions without the risk of thermal deformation.

[0012] Optionally, cooling data during each batch of cooling process is stored; based on the stored cooling data, the preset cooling strategy parameters are iteratively updated for different roll diameters and / or materials of the pole rolls.

[0013] Optionally, the condition for determining the end of the cooling process is set as follows: the real-time temperature detected by the first temperature sensor reaches a preset target value, and the duration of maintaining the target value or within its allowable fluctuation range meets a preset threshold.

[0014] Optionally, the cooling system includes a cooling component and an air guide component. The cooling component can cool the cooling medium guided by the air guide component to the target chamber. A second temperature sensor and a velocity sensor are provided at the air inlet end of the target chamber. The control component can dynamically adjust the cooling power of the cooling component on the cooling medium according to the temperature detected by the second temperature sensor, so as to adjust the cooling effect of the cooling component on the cooling medium. The control component can dynamically adjust the exhaust power of the air guide component according to the flow rate detected by the velocity sensor, so as to adjust the flow rate of the cooling medium.

[0015] Optionally, multiple electrode rolls are arranged at equal intervals along the length of the target chamber, and the first temperature sensor is disposed in the middle of the multiple electrode rolls.

[0016] The electrode roll provided in this application limits the deformation curvature, moisture content, and wrinkle defect rate of the electrode sheet in the electrode roll product to a specific range, providing a product with higher appearance quality and stable physicochemical properties that is different from the electrode rolls produced by conventional quenching processes. This product can directly indicate that the internal thermal stress of the electrode sheet is effectively released, the moisture is fully discharged, and the structure remains uniform, thereby solving the problems of electrode sheet deformation and moisture content rebound caused by defects in the production process, and providing a more reliable raw material basis for downstream cell manufacturing. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the electrode cooling device provided in this embodiment.

[0019] Figure 2 This is a flowchart of the control method for cooling the electrode roll.

[0020] Figure 3 Flowchart of the preset cooling strategy Figures 1 to 3 middle: 1-Cooling system, 2-Target chamber, 3-First temperature sensor, 4-Velocity sensor, 5-Second temperature sensor, 6-Electrode roll; 101-Cooling component, 102-Air guide component. Detailed Implementation

[0021] This application provides an electrode roll that at least solves the problems of large electrode deformation curvature, high electrode moisture content, and high electrode wrinkling defect rate caused by poor electrode roll cooling. This application also provides a method for controlling the cooling of the electrode roll.

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] In the lithium battery electrode winding and baking process, to achieve cooling of the baked electrode roll 6, the commonly used approach in related technologies is to directly switch to a direct cooling mode after the electrode has been baked at high temperature for a preset time. This involves using a constant, high-volume flow of ambient temperature or forced cooling gas to rapidly cool the oven cavity and the electrode until the discharge temperature is reached. The basic working principle of this scheme relies on forced convection heat transfer between a high-flow-rate cooling medium and the high-temperature electrode to quickly remove heat. Its widespread application is mainly due to its ability to complete the process cycle in a short cooling time and its simple equipment control logic.

[0024] However, when this solution is applied to electrode roll 6 products, which are sensitive to thermal stress and have a large roll diameter, its performance is not ideal. A fundamental contradiction lies in the fact that, in pursuit of rapid cooling, the inherently strong and gradient-free cooling method inevitably causes a huge instantaneous temperature difference between the surface and the interior of the electrode, and between the outer and inner rings, thereby damaging the structural uniformity and moisture stability of the electrode. Specifically, during the cooling process after baking of the wound electrode, the high-temperature electrode suddenly comes into contact with the low-temperature airflow. The surface layer contracts rapidly while the interior remains in a state of high-temperature expansion. This uneven contraction easily leads to deformations such as warping, wrinkling, and loose edges in the electrode. At the same time, the pores of the electrode contract instantly due to the rapid cooling of the surface, sealing in residual moisture that has not yet migrated to the surface. This causes a rebound in moisture content after cooling, creating potential hazards for subsequent cell expansion and self-discharge.

[0025] Through in-depth analysis, the inventors discovered that the root cause of the aforementioned contradiction lies in the fact that the open-loop timing control method used in related technologies lacks the ability to perceive and adjust the actual thermal state of the electrode in real time. Its cooling intensity and cooling rate remain constant throughout the process, failing to adapt to the differences in the electrode's sensitivity to cooling rates across different temperature ranges. The high-temperature stage is precisely the critical window for thermal stress release and moisture removal; excessive cooling irreversibly causes structural damage and moisture trapping, and open-loop control cannot identify this stage and provide protection.

[0026] To overcome the aforementioned contradictions, this disclosure proposes a different technical approach. Its core concept lies in introducing a segmented gradient cooling closed-loop control based on real-time temperature feedback. This differentiates the entire cooling process from high to low temperature, limiting the cooling rate in the initial high-temperature stage to smoothly release thermal stress and remove moisture, while increasing the cooling rate in the subsequent low-temperature stage to shorten process time. This achieves both reduced deformation and moisture content rebound risks while maintaining production efficiency. Specifically, it provides a control method based on dynamically adjusting the cooling medium supply intensity according to temperature signals to solve the deformation and moisture abnormalities caused by temperature shocks during the rapid cooling process of the 6-rolled steel product, thus achieving a stable improvement in the appearance quality and physical and chemical properties of the 6-rolled steel product.

[0027] This application provides an electrode roll 6, which can be applied to the winding structure of various battery electrodes, especially in the field of lithium-ion battery manufacturing. After the electrode sheet is coated, rolled, and slit, it is wound into an electrode roll 6 and baked to remove internal moisture and residual solvents. The baked electrode roll 6 needs to undergo a cooling process before proceeding to the next manufacturing stage. The electrode roll 6 described in this application has specific physical performance indicators, which directly characterize the degree of internal thermal stress release, moisture content stability, and appearance quality of the electrode roll 6 after the cooling process. (Reference) Figure 1 Electrode roll 6 is formed by winding an electrode sheet, which includes a current collector and an active material layer disposed on the surface of the current collector, forming a multi-layer structure after winding. After high-temperature baking, electrode roll 6 undergoes a controlled cooling process to finally obtain a product with specific deformation curvature, moisture content and wrinkle defect rate.

[0028] refer to Figure 1According to the embodiments of this application, electrode roll 6 includes an electrode sheet with a deformation arc of 1.5-3.5 mm / m, a moisture content of 85-105 ppm, and a wrinkle defect rate of 0.3%-0.7%. The deformation arc refers to the degree of macroscopic deformation of the electrode sheet in the winding direction or width direction, typically measured using an arc gauge or non-contact imaging measuring instrument, and expressed as a deviation per unit length (mm / m). This parameter reflects the level of residual stress inside the electrode sheet after thermal processing; a smaller deformation arc indicates more complete release of thermal stress during cooling and higher electrode sheet flatness. Moisture content refers to the residual moisture content inside the electrode sheet after baking and cooling, generally detected by Karl Fischer coulometric method or loss on drying method, with ppm representing parts per million by mass. Moisture content directly affects subsequent battery electrolyte filling processes and the electrochemical performance of the battery cell. The wrinkle defect rate refers to the percentage of electrode area or length with visible defects such as wrinkles and ripples, which can be identified by the naked eye or through an online visual inspection system in continuously produced electrodes. The wrinkle defect rate directly reflects the degree of non-uniform shrinkage of the electrode due to temperature gradients during the cooling process.

[0029] Specifically, the deformation radius is set at 1.5-3.5 mm / m. If this value is less than 1.5 mm / m, it means that the cooling process may be too conservative, with an excessively low cooling rate. Although the electrode deformation is minimal, the production cycle time is significantly extended, and slow cooling may cause the electrode to remain in the high-temperature range for too long, which is detrimental to maintaining the stability of the active material structure. If this value is greater than 3.5 mm / m, the residual thermal stress inside the electrode is too high, which can easily lead to decreased alignment and misalignment of the electrode edges during subsequent winding of the battery cell, and even cause battery cell deformation and internal short circuit risks. The moisture content is set at 85-105 ppm. If the moisture content is less than 85 ppm, it indicates that the baking or cooling process may be over-drying, and the binder in the electrode may become brittle, reducing the flexibility and processability of the electrode. If the moisture content is greater than 105 ppm, it means that the moisture inside the electrode is not completely drained. The residual moisture in the pores will react with the electrolyte during subsequent liquid injection and formation processes, causing battery cell expansion and self-discharge, which seriously affects cycle life and safety performance. The wrinkle defect rate is set at 0.3%-0.7%. If it is below 0.3%, the requirements for equipment and processes are extremely high, resulting in poor economic efficiency for mass production, and it is difficult to achieve consistently under current technological conditions. If it is above 0.7%, the appearance quality of the electrode sheet will significantly decrease, and the density of the active material layer in the wrinkled area will be uneven, leading to a deterioration in the consistency of cell capacity and internal resistance, thus increasing the defect rate. By simultaneously limiting the deformation curvature, moisture content, and wrinkle defect rate within the above ranges, an electrode roll 6 product with effectively relaxed internal stress, precise moisture control, and high appearance quality can be obtained, providing a reliable material basis for downstream cell manufacturing.

[0030] In another embodiment, the deformation curvature of the electrode sheet can be further controlled to 2.0-3.0 mm / m, the moisture content to 90-100 ppm, and the wrinkle defect rate to 0.4%-0.6%, to achieve better product consistency. Electrode roll 6 is applicable to different cathode material systems such as lithium iron phosphate, ternary materials, and lithium cobalt oxide, as well as graphite and silicon-based anode material systems. The electrode sheet thickness and compaction density can be adjusted according to battery design requirements.

[0031] This application also provides a control method for cooling the electrode roll 6, which has specific physical performance indicators. This method uses a closed-loop feedback mechanism to finely manage the cooling process, thereby ensuring electrode quality while maintaining production efficiency. (Reference) Figure 1 The cooling system 1 includes a cooling component 101 and an air guide component 102. The target chamber 2 is the oven cavity, and the electrode roll 6 is placed inside the oven cavity. A blower, acting as the air guide component 102, delivers the cooling medium (e.g., nitrogen or dry air) into the temperature control system. After temperature adjustment, the medium is introduced into the oven cavity through a pipe. A speed sensor 4 detects the flow rate of the cooling medium after temperature adjustment, and a second temperature sensor 5 detects the temperature of the cooling medium after temperature adjustment and feeds it back to the control unit (not shown). Inside the oven cavity, a thermometer is installed beside the electrode roll 6 as a first temperature sensor 3 to monitor the temperature near the electrode roll 6 or the electrode roll itself. The control unit can be a programmable logic controller, a microprocessor, or an industrial computer, which stores preset cooling strategy parameters and executes the cooling control program. When cooling is complete, the electrode roll 6 is cooled to the discharge temperature, and then the cavity door can be opened to remove it.

[0032] refer to Figure 1 and Figure 2 The control method for cooling the electrode roll is executed by a control unit and includes the following steps: S001: Control the cooling system 1 to introduce cooling medium into the target chamber 2 where the electrode roll 6 is located. S002: Obtain the real-time temperature signal from the first temperature sensor 3 located beside the electrode roll 6. S003: Based on the real-time temperature signal and preset cooling strategy parameters, dynamically adjust the intensity of the cooling medium supplied by the cooling system 1 into the target chamber 2. The preset cooling strategy parameters are defined as limiting the cooling rate during the initial high-temperature stage measured by the first temperature sensor 3, and increasing the cooling rate during the subsequent low-temperature stage measured by the first temperature sensor 3.

[0033] In step S001, the controller drives the blower and temperature control system, and opens the corresponding valves to allow cooling medium with a certain temperature and flow rate to enter the oven cavity, thereby removing heat from the electrode roll 6. In step S002, the first temperature sensor 3 collects the temperature of the area where the electrode roll 6 is located in real time, and this temperature signal is input to the controller as feedback. In step S003, the preset cooling strategy parameters refer to a series of control target values ​​or limits such as the desired cooling rate, air volume, and air pressure associated with the temperature range. Dynamically adjusting the supply intensity means that the controller, based on the current real-time temperature and its changing trend, and in conjunction with the cooling strategy parameters, adjusts the rotation speed of the air guide 102 to change the cooling medium flow rate, and / or adjusts the cooling power of the cooling system 1 to change the cooling medium temperature, thereby changing the amount of heat removed from the electrode roll 6 per unit time. The high-temperature stage typically refers to the initial temperature after baking and the range between a certain medium and high temperature. During this stage, the temperature difference between the electrode roll 6 and the cooling medium is large. If the cooling rate is too high, the surface of the electrode will shrink rapidly while the interior remains in a state of thermal expansion, resulting in significant internal stress. Therefore, limiting the cooling rate can effectively protect the electrode structure. As the temperature decreases, the thermal sensitivity of the electrode material decreases, and the risk of thermal deformation decreases. At this point, the cooling rate can be appropriately increased to accelerate the production cycle.

[0034] This control method, by introducing real-time temperature feedback and implementing a dynamic cooling strategy with high and low temperature zones, abandons the traditional fixed-intensity direct cooling mode. It precisely controls electrode roll 6 to avoid thermal shock in the sensitive temperature range and efficiently cools it in the non-sensitive range, thereby reducing electrode deformation and residual stress at the source and avoiding moisture rebound issues. Compared to open-loop timed cooling, this method is adaptive to factors such as differences in electrode roll 6 diameter and ambient temperature fluctuations, exhibiting high overlap in cooling curves between different batches and good product consistency.

[0035] In addition to the blower and temperature control system, the cooling system 1 may also include a return air duct and a heat exchanger to recover some energy. The control unit may also employ advanced algorithms such as fuzzy control and model predictive control to perform the dynamic adjustments in S003, rather than being limited to simple threshold comparisons.

[0036] To specify the parameters of the cooling strategy mentioned above and achieve quantifiable segmented control, the preset cooling strategy can adopt a segmented cooling method. Please refer to [link / reference]. Figure 3When the first temperature sensor 3 is in a first stage where the temperature is greater than the first target temperature T1, the controller controls the cooling system 1 to supply cooling medium to the target chamber 2 at a temperature of T1 and a rate of t1℃ / min. When the first temperature sensor 3 is in a second stage where the temperature is less than or equal to T1 and greater than the second target temperature T2, the controller controls the cooling system 1 to supply cooling medium to the target chamber 2 at a temperature of T2 and a rate of t2℃ / min. When the first temperature sensor 3 is in a third stage where the temperature is less than or equal to T2 and greater than the third target temperature T3, the controller controls the cooling system 1 to supply cooling medium to the target chamber 2 at a temperature of T3 and a rate of t3℃ / min. Wherein, t1, t2, and t3 satisfy: t1 < t2 < t3.

[0037] The first target temperature T1, the second target temperature T2, and the third target temperature T3 are the temperature thresholds for switching the trigger stage, with T1 > T2 > T3. For example, T1 can be set to 100℃-120℃, T2 to 60℃-80℃, and T3 to 30℃-50℃. t1, t2, and t3 are the maximum allowable cooling rate or target cooling rate in the three stages, respectively. t1 is the cooling rate in the high-temperature stage, which is set relatively low due to the sensitivity of electrode roll 6 to temperature differences; t2 is the cooling rate in the medium-temperature stage, which is appropriately increased while ensuring structural stability; and t3 is the cooling rate in the low-temperature stage, which can be further increased to quickly complete cooling. By dividing the cooling process into three stages with progressively increasing cooling rates, a low-rate cooling is achieved in the high-temperature sensitive range to fully release thermal stress, a moderate-rate cooling is achieved in the medium-temperature range to stably remove water vapor, and a high-rate cooling is achieved in the low-temperature safe range to shorten the total process time, thus achieving a balance between quality and efficiency. If t1 is too large, the first stage of cooling will be too fast, leading to high-temperature shock, electrode deformation, and residual stress. If t1 is too small, the first stage will take too long, reducing production efficiency. If t3 is too small, the cooling in the low-temperature section will be insufficient, resulting in an excessively high discharge temperature, which will affect subsequent processes. If t3 is too large, although there is no risk of deformation in the low-temperature section, the excessively high wind speed may cause the electrode surface to vibrate or dust to fall off.

[0038] In alternative implementations, the cooling phase can also be divided into two or four phases. In the case of two phases, the high-temperature phase and the medium-temperature phase can be combined. In the case of four phases, the medium-temperature phase can be further subdivided into a transition phase. The cooling rate of each phase still satisfies the increasing relationship of first low and then high.

[0039] In the first stage, to prevent the actual cooling rate from unexpectedly exceeding the set value due to control fluctuations or system response delays, proactive protection measures can be implemented: real-time monitoring of the cooling rate. If the cooling rate is detected to exceed the set value, the heating power is automatically compensated and / or the air intake volume is reduced. Specifically, monitoring the cooling rate can be achieved by continuously collecting the temperature value of the first temperature sensor 3 and calculating the temperature difference per unit time, with the set value being t1. When the controller determines that the actual cooling rate exceeds t1, it sends a command to the temperature control system to activate the auxiliary heating mode (e.g., micro-heating the cooling medium through an electric heating element) to compensate for some of the cooling capacity, or to reduce the speed of the blower to reduce the amount of cold air entering the cavity, thereby forcibly pulling the actual cooling rate back below t1. This measure forms a proactive safety barrier against the risk of excessively rapid cooling, ensuring that the electrode roll 6 is always under speed-limiting protection during the high-temperature slow-drying stage. Even if there are minor disturbances in the control system, it can be corrected in time to prevent irreversible thermal deformation of the electrode due to instantaneous rapid cooling.

[0040] In another embodiment, the adjustment can be made by only compensating for the heating power or only reducing the air intake volume, or by adjusting proportionally according to the extent to which the cooling rate exceeds the set value. The greater the deviation, the higher the heating compensation power and the greater the reduction in air volume.

[0041] In the second stage, to ensure the smoothness of the cooling process and prevent uneven shrinkage of the electrode pores due to deviations from the expected standard path caused by fluctuations in operating conditions, the actual cooling curve can be compared with the preset standard curve in real time, and the air pressure parameters can be dynamically adjusted based on the comparison results. Specifically, the preset standard curve is a temperature-time curve obtained through process optimization, representing the ideal thermal history of electrode roll 6 in this stage, which can balance thermal stress release and stable water vapor discharge. During the execution of the second stage, the control unit reads the temperature value of the first temperature sensor 3 at regular intervals (e.g., 1 second), forming discrete points on the actual cooling curve, and compares them with the expected temperature value at the same time on the standard curve to calculate the deviation. Based on the magnitude and direction of the deviation, the outlet air pressure of the blower is dynamically adjusted or the cavity air pressure is changed by adjusting the opening of the exhaust valve to adjust the heat exchange efficiency and make the actual temperature return to the standard trajectory as soon as possible. For example, if the actual temperature is higher than the expected temperature, the air pressure is increased to enhance heat dissipation; if the actual temperature is lower than the expected temperature, the air pressure is decreased to mitigate heat dissipation. Therefore, the second-stage cooling process can proceed strictly along the standard path, allowing the pores inside the electrode to shrink uniformly, and the moisture to migrate smoothly from the inside to the outside and be carried away by the airflow, effectively avoiding the phenomenon of moisture sealing and rebound.

[0042] The data for the standard curve can be obtained based on simulation calculations or experimental measurements, and multiple sets of standard curves can be pre-stored for different roll diameters or materials.

[0043] The third stage begins when the real-time temperature drops to a preset low-temperature safety threshold. During this stage, the electrode roll 6 is cooled at its maximum rate under conditions of no risk of thermal deformation. Specifically, the low-temperature safety threshold refers to the temperature below which the electrode roll 6 material no longer exhibits the conditions for macroscopic thermal deformation or microcracks; for example, it can be 40℃-50℃. When the temperature detected by the first temperature sensor 3 drops below this threshold, the controller determines that the electrode roll 6 structure is completely stable. It then releases the cooling rate restriction from the previous stage, sets the blower to its maximum safe speed, and sets the temperature control system to its maximum cooling capacity. The electrode roll 6 is rapidly cooled with an extremely high airflow and the lowest possible medium temperature until the target discharge temperature is reached. Using the low-temperature safety threshold as the sole trigger condition for entering the third stage ensures that rapid cooling only occurs in the risk-free low-temperature zone, eliminating the risk of residual thermal stress. By employing maximum cooling rate, the time spent in the low-temperature section is minimized while maintaining quality, resulting in a significantly shorter overall process time compared to the entire gradual cooling process, achieving a balance between quality and efficiency.

[0044] In another control logic, the maximum rate of cooling can be determined based on the pressure resistance of the cavity structure and the upper limit of the safe wind speed of the pole roll 6 fixing method, rather than the maximum physical limit of the blower.

[0045] To continuously improve the adaptability of the control method to different specifications of electrode rolls 6, cooling data during each batch of cooling can be stored. Based on the stored cooling data, the preset cooling strategy parameters are iteratively updated for different electrode roll diameters and / or materials. Specifically, the data generated during each batch of cooling includes, but is not limited to: the roll diameter, material type, initial temperature, ambient temperature, actual cooling curves at each stage, actual triggering thermal times of T1, T2, and T3, actual execution rates of t1, t2, and t3, heating compensation, wind pressure correction, and quality inspection results such as the final electrode sheet's deformation curvature, moisture content, and wrinkle defect rate. This data is stored in a database or cloud server connected to the control unit. After accumulating a certain amount of data on the same specification of electrode roll 6, the control component operation parameter optimization algorithm (such as gradient descent, genetic algorithm, or Bayesian optimization) automatically calculates updated cooling strategy parameters, including better temperature thresholds T1, T2, T3 and cooling rates t1, t2, t3, constrained by the quality index compliance rate and aimed at shortening the total cooling time, and adopts them in subsequent batches of the same specification. For electrode roll 6 with different roll diameters (e.g., large roll diameters have slower heat dissipation) and different materials (e.g., different cathode materials have different thermal conductivity), the system establishes separate datasets and iterates independently, thus forming a self-learning and self-evolving parameter optimization system, so that the cooling control always approaches the optimal solution.

[0046] The frequency of iterative updates can be based on the cumulative number of batches or triggered by a time period, or it can be updated after manual confirmation by the operator.

[0047] During iterative optimization using historical data, it is necessary to accurately determine whether each cooling process is truly complete to ensure that the data used for optimization reflects a complete and stable cooling cycle. Therefore, the condition for determining the end of the cooling process can be set as follows: the real-time temperature detected by the first temperature sensor 3 reaches the preset target value, and the duration of maintenance at the target value or within its allowable fluctuation range meets the preset threshold.

[0048] The preset target value is the discharge temperature, for example, 25℃-35℃. Once the temperature reaches the target value, the system does not immediately end the cooling process but enters a stable holding phase. During this phase, the controller continuously monitors the temperature. If the temperature remains within the allowable fluctuation range (e.g., ±1℃) and this holding time exceeds a preset threshold (e.g., 5-10 minutes), the entire cooling process is considered complete, the internal thermal field of electrode roll 6 is fully balanced, and the door can be opened for discharge. Using temperature reaching the target value plus the stabilization time as the termination condition prevents premature termination of cooling when the temperature just reaches the target value but a temperature gradient still exists internally. This ensures that each recorded process data represents a true and complete cooling process, thereby guaranteeing the accuracy of the dataset and the reliability of subsequent parameter optimization. Simultaneously, this determination method ensures a high degree of consistency in the state of electrode roll 6 at the end of cooling for each batch, improving the repeatability of quality between batches.

[0049] The preset threshold for the stable duration can be adjusted based on the maximum roll diameter of the pole roll 6 and the thermal diffusivity of the material.

[0050] To ensure the stability of the parameters of the cooling medium supplied to the target chamber 2, thereby providing an accurate basis for the entire cooling control, the cooling system 1 includes a cooling component 101 and an air guide component 102. The cooling component 101 cools the cooling medium guided to the target chamber 2 by the air guide component 102. A second temperature sensor 5 and a velocity sensor 4 are installed at the air inlet of the target chamber 2. The control component can dynamically adjust the cooling power of the cooling component 101 on the cooling medium according to the temperature detected by the second temperature sensor 5, so as to adjust the cooling effect of the cooling component 101 on the cooling medium; the control component can dynamically adjust the exhaust power of the air guide component 102 according to the flow rate detected by the velocity sensor 4, so as to adjust the flow rate of the cooling medium.

[0051] The cooling component 101, or temperature control system, can take the form of a refrigeration compressor, a semiconductor cooling chip, or a liquid nitrogen heat exchanger. Its function is to precisely control the temperature of the cooling medium delivered by the blower, ensuring it reaches the desired temperature. The air guide component 102, or blower, has its exhaust power adjusted by a frequency converter to regulate the motor speed. The second temperature sensor 5, or thermometer, and the speed sensor 4, or anemometer, are respectively installed in the pipeline after the temperature control system and before the air inlet of the oven cavity to detect the temperature and flow rate of the cooling medium entering the cavity in real time. The control unit has two inner closed loops: the temperature inner loop compares the temperature reading with the target medium temperature based on the thermometer feedback and adjusts the cooling power of the temperature control system to eliminate medium temperature deviation; the flow rate inner loop compares the flow rate with the target flow rate based on the anemometer feedback and adjusts the blower speed to eliminate flow rate deviation. Through these two inner loop controls, the cooling medium is in a precisely controlled state before being sent into the cavity, eliminating interference from factors such as changes in external ambient temperature and fluctuations in pipeline resistance on the medium supply. This ensures that the S003 step in the main cooling closed loop can be implemented under stable and reliable input conditions, guaranteeing the precise execution of the segmented cooling strategy.

[0052] In another embodiment, the cooling component 101 can also be a heat exchanger, and the medium temperature can be controlled by adjusting the cooling water flow rate. The air guide component 102 can also be a speed-regulating fan or a compressed air pipeline controlled by a proportional valve.

[0053] In production scenarios where multiple electrode rolls 6 need to be cooled simultaneously within the target chamber 2, multiple electrode rolls 6 are evenly spaced along the length of the target chamber 2, with a first temperature sensor 3 positioned at the center of each electrode roll 6. Here, the first temperature sensor 3 is installed beside or inside the core of the central electrode roll 6, and the temperature it measures is the highest or least favorable temperature for heat dissipation among all electrode rolls 6. The control unit uses this temperature as the representative temperature of all electrode rolls 6 in the chamber for cooling control. This ensures that while the central electrode roll 6, with the highest thermal inertia, is adequately protected from thermal shock, the other edge electrode rolls 6, which dissipate heat faster, will not experience excessive temperature differences. This temperature measurement method avoids prematurely accelerating overall cooling by selecting lower edge temperatures, thus preventing the central electrode roll 6 from suffering temperature shocks and ensuring the consistency and safety of the cooling effect across the entire chamber of electrode rolls 6.

[0054] The number of multiple electrode rolls 6 can be 3 to 10. The first temperature sensor 3 can also be set at multiple positions in the middle part of the count from the center to both ends, and the average or highest value is taken as the control input to further enhance representativeness.

[0055] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

[0056] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0057] It should also be noted that in the apparatus, equipment, and methods of this application, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered as equivalent solutions of this application.

[0058] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0059] It should be understood that the qualifiers “first,” “second,” “third,” “fourth,” “fifth,” and “sixth” used in the description of the embodiments of this application are only used to more clearly illustrate the technical solutions and are not intended to limit the scope of protection of this application.

[0060] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A type of polar roll, characterized in that, The electrode roll includes an electrode sheet, the deformation curvature of the electrode sheet is 1.5-3.5 mm / m, the moisture content of the electrode sheet is 85-105 ppm, and the wrinkle defect rate of the electrode sheet is 0.3%-0.7%.

2. A method for controlling the cooling of an electrode roll, characterized in that, For cooling the electrode roll according to claim 1, the control method for cooling the electrode roll is executed by a control unit and includes the following steps: S001: Control the cooling system to introduce cooling medium into the target chamber where the pole rolls are installed; S002: A first temperature sensor is provided on the side of the electrode roll to obtain the real-time temperature signal of the first temperature sensor; S003: Based on the real-time temperature signal and preset cooling strategy parameters, dynamically adjust the intensity of the cooling medium supplied by the cooling system to the target chamber; The preset cooling strategy parameters are defined as follows: limiting the cooling rate during the initial high-temperature phase measured by the first temperature sensor, and increasing the cooling rate during the subsequent low-temperature phase measured by the first temperature sensor.

3. The control method for the cooling electrode roll according to claim 2, characterized in that, The preset cooling strategy is segmented cooling, including: When the first temperature sensor is in a first stage where it is greater than the first target temperature T1, the controller controls the cooling system to supply the cooling medium to the target chamber at the T1 temperature and a rate of t1℃ / min; when the first temperature sensor is in a second stage where it is less than or equal to T1 and greater than the second target temperature T2, the controller controls the cooling system to supply the cooling medium to the target chamber at the T2 temperature and a rate of t2℃ / min; when the first temperature sensor is in a third stage where it is less than or equal to T2 and greater than the third target temperature T3, the controller controls the cooling system to supply the cooling medium to the target chamber at the T3 temperature and a rate of t3℃ / min. Wherein, t1, t2 and t3 satisfy: t1 < t2 < t3.

4. The control method for cooling electrode rolls according to claim 3, characterized in that, In the first stage, the cooling rate is monitored in real time. If the cooling rate exceeds the set value, the heating power is automatically compensated and / or the air intake volume is reduced.

5. The control method for the cooling electrode roll according to claim 3, characterized in that, In the second stage, the actual cooling curve is compared with the preset standard curve in real time, and the wind pressure parameters are dynamically adjusted based on the comparison results.

6. The control method for cooling electrode rolls according to claim 3, characterized in that, The third stage is initiated after the real-time temperature drops to a preset low-temperature safety threshold, and during this stage, the pole roll is cooled at the maximum rate under conditions without the risk of thermal deformation.

7. The control method for cooling electrode rolls according to claim 2, characterized in that, Store cooling data for each batch of cooling process; based on the stored cooling data, iteratively update the preset cooling strategy parameters for different roll diameters and / or materials of the pole rolls.

8. The control method for cooling electrode rolls according to claim 7, characterized in that, The condition for determining the end of the cooling process is set as follows: the real-time temperature detected by the first temperature sensor reaches the preset target value, and the duration of the temperature maintained at the target value or within its allowable fluctuation range meets the preset threshold.

9. The control method for cooling electrode rolls according to claim 2, characterized in that, The cooling system includes a cooling component and an air guide component. The cooling component cools the cooling medium directed by the air guide component to the target chamber. A second temperature sensor and a velocity sensor are provided at the air inlet of the target chamber. The control component dynamically adjusts the cooling power of the cooling component on the cooling medium according to the temperature detected by the second temperature sensor to adjust the cooling effect of the cooling component on the cooling medium. The control component dynamically adjusts the exhaust power of the air guide component according to the flow rate detected by the velocity sensor to adjust the flow rate of the cooling medium.

10. The control method for cooling electrode rolls according to claim 2, characterized in that, Along the length of the target chamber, multiple electrode rolls are arranged at equal intervals, and the first temperature sensor is disposed in the middle of the multiple electrode rolls.

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