Battery double-layer coating surface density closed-loop control method and device based on multi-spectrum rays

Abstract

This invention belongs to the field of battery manufacturing technology and relates to a closed-loop control method and apparatus for the areal density of a double-layer coating in batteries based on multispectral X-rays. The method includes: emitting a first ray and a second ray onto the double-layer coating surface on one side of the substrate, respectively; collecting first transmission data and second transmission data from the opposite side of the substrate; constructing a set of ray attenuation equations corresponding to the first and second rays based on the principle of ray attenuation, according to the attenuation coefficients of the first coating, the second coating, and the substrate structure obtained through pre-calibration experiments; solving the ray attenuation equations based on the first and second transmission data to obtain the areal density of the first coating and the second coating; and adjusting the operating speed of the slurry delivery unit based on the areal density control target deviation. This method accurately obtains independent areal densities, significantly improving the consistency of the coating ratios.

Description

Technical Field

[0001] This invention belongs to the field of battery manufacturing technology and relates to a closed-loop control method and device for the surface density of a double-layer coating for batteries based on multispectral X-rays. Background Technology

[0002] With the rapid popularization of new energy vehicles and electronic devices, the market has placed higher demands on the energy density, cycle performance, and range of batteries. Among them, electrochemical energy storage batteries such as lithium-ion batteries, sodium-ion batteries, and solid-state batteries all face an urgent need for performance upgrades. As a core link in the manufacturing of various batteries, the coating process directly determines the stability of the electrode structure and the overall lifespan of the battery. Among them, double-layer coating technology has become the mainstream direction in the industry because it can optimize electrode function and balance high energy density and fast charging performance. However, the real-time monitoring and precise control of the independent surface density of the upper and lower coatings remains a technical challenge.

[0003] Existing technologies have significant limitations: traditional single-layer coating models are based on the assumption of a single-layer structure, which cannot distinguish the independent contributions of the upper and lower coatings to the total areal density, easily leading to uncontrolled interlayer proportions; among mainstream detection technologies, While online X-ray inspection achieves an accuracy of ±0.25‰, the complexity of the equivalent attenuation coefficient of the mixed slurry makes it difficult to perform layer-by-layer analysis. Laser thickness measurement technology (accuracy ±1.0μm) can only obtain the total thickness and cannot deduce the independent areal density of the upper and lower coatings. These problems directly lead to production pain points such as poor coating consistency, insufficient electrode stability, serious slurry waste, and high scrap rates. Furthermore, existing technologies lack real-time online monitoring and closed-loop control capabilities for the independent areal density of the upper and lower coatings, making it difficult to meet the demands of high-quality production. Therefore, there is an urgent need to develop a method that breaks through the current technological bottlenecks and enables independent monitoring and precise control of the areal density of the upper and lower coatings to improve the performance and production efficiency of various batteries. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned problems in existing technologies by proposing a closed-loop control method for the surface density of double-layer coatings in batteries based on multispectral X-rays.

[0005] The objective of this invention can be achieved through the following technical solution: a closed-loop control method for the surface density of a double-layer coating for batteries based on multispectral X-rays, comprising: A first radiation source and a second radiation source are arranged along the width of the substrate to emit the first radiation and the second radiation onto the double-coated surface on one side of the substrate, respectively, and to collect the first transmission data and the second transmission data from the other side of the substrate opposite the coating surface. Based on the attenuation coefficients of the first coating, the second coating, and the substrate structure obtained through prior experimental calibration, a set of ray attenuation equations corresponding to the first ray and the second ray is constructed based on the principle of ray attenuation. Based on the first transmission data and the second transmission data, the corresponding ray attenuation equations are solved to obtain the areal density of the first coating and the areal density of the second coating. Based on the areal density of the first coating and the areal density of the second coating, the operating speed of the slurry conveying unit is adjusted according to the target deviation controlled by the areal density.

[0006] As an optional embodiment of the present invention, the substrate structure is a pure substrate; based on the attenuation coefficients of the first coating, the second coating, and the substrate obtained through prior experimental calibration, and based on the principle of ray attenuation, a set of ray attenuation equations corresponding to the first ray and the second ray is constructed, including: A standard sample is prepared, wherein the standard sample is the substrate, and a second coating and a first coating are sequentially provided on one side surface of the substrate; The first and second rays were used to irradiate the double-layer coated surface of the standard sample, and the first calibration transmission data and the second calibration transmission data were measured. The thicknesses of the first coating, the second coating, and the substrate are measured. Based on the principle of radiation attenuation, the attenuation coefficients of the first coating, the second coating, and the substrate corresponding to the first and second rays are calculated according to the first and second calibration transmission data, respectively. A coefficient matrix is ​​established based on the attenuation coefficients. Based on the coefficient matrix and the principle of ray attenuation, a set of ray attenuation equations corresponding to the first ray and the second ray is constructed.

[0007] As an optional embodiment of the present invention, the substrate structure is a substrate that has been double-coated on the other side; Based on the attenuation coefficients of the first coating, the second coating, and the substrate structure obtained through prior experimental calibration, and based on the principle of ray attenuation, a set of ray attenuation equations corresponding to the first ray and the second ray is constructed, including: Prepare a standard sample, wherein the standard sample is a substrate that has been double-coated on one side, and a second coating and a first coating are sequentially applied to the opposite side surface; The first and second rays are used to irradiate the double-layer coated surface on the other side, and the corresponding first calibration transmission data and second calibration transmission data are measured. The overall thickness of the first coating, the second coating, and the substrate structure is measured. Based on the principle of ray attenuation, the attenuation coefficients of the first coating, the second coating, and the substrate structure corresponding to the first ray and the second ray are calculated according to the first calibration transmission data and the second calibration transmission data. A coefficient matrix is ​​established based on the attenuation coefficients. Based on the coefficient matrix and the principle of ray attenuation, a set of ray attenuation equations corresponding to the first ray and the second ray is constructed.

[0008] As an optional embodiment of the present invention, the ray attenuation equations are solved by the least squares method or a nonlinear fitting method to obtain the areal density of the first coating and the areal density of the second coating.

[0009] As an optional embodiment of the present invention, the operating speed of the slurry conveying unit is adjusted based on the areal density of the first coating and the areal density of the second coating, according to the areal density control target deviation, including: The areal density of the first coating is fed back to the servo driver of the slurry delivery unit corresponding to the first coating, and the areal density of the second coating is fed back to the servo driver of the slurry delivery unit corresponding to the second coating. The servo driver adjusts the operating speed of the corresponding slurry conveying unit according to the target deviation of the first coating surface density, the target surface density of the first coating, the target deviation of the second coating surface density, the target surface density of the second coating, and the total surface density constraint of the current double-layer coating.

[0010] As an optional embodiment of the present invention, it further includes: Calculate the ratio of the areal density of the second coating to the areal density of the first coating; Calculate the absolute value of the deviation between the ratio and the preset ratio; Based on the absolute value of the deviation and the duration of the absolute value of the deviation, it is determined whether an interlayer mixing defect has occurred; In cases where interlayer mixing defects are determined to occur, the defect location and duration are marked based on the substrate conveyor speed and data acquisition timestamp. The defect location, duration, and ratio are fed back to the corresponding servo driver to adjust the operating speed of the corresponding slurry conveying unit.

[0011] As an optional embodiment of the present invention, a scintillator detector array is arranged along the width direction of the substrate to collect a first ray transmission intensity sequence and a second ray transmission intensity sequence from the other side of the substrate opposite the double-coated surface. The first X-ray transmission intensity sequence and the second X-ray transmission intensity sequence are converted from data to data to obtain the first transmission data and the second transmission data.

[0012] As an optional embodiment of the present invention, the first ray is a beta ray and the second ray is an X-ray.

[0013] As an optional embodiment of the present invention, the slurry delivery unit is a screw pump, and the servo driver controls the delivery amount of the corresponding coating slurry by adjusting the rotation speed of the screw pump.

[0014] This invention also proposes a closed-loop control device for the surface density of a battery double-layer coating based on multispectral X-rays, comprising: The X-ray mounting and emission module is used to arrange the first X-ray source and the second X-ray source along the width direction of the substrate, and emit the first X-ray and the second X-ray respectively onto the double-coated surface on one side of the substrate; A radiation data acquisition module is used to acquire first transmission data and second transmission data from the other side of the substrate opposite the double-coated surfaces. The equation system module is used to construct the ray attenuation equation system corresponding to the first ray and the second ray based on the ray attenuation principle, according to the attenuation coefficients of the first coating, the second coating and the substrate structure obtained through experimental calibration in advance. The areal density calculation module is used to solve the ray attenuation equation set according to the first transmission data and the second transmission data to obtain the areal density of the first coating and the areal density of the second coating. The control module is used to adjust the operating speed of the slurry conveying unit based on the areal density of the first coating and the areal density of the second coating, and to control the target deviation based on the areal density.

[0015] The present invention also provides an electronic device, comprising: processor; Memory used to store processor-executable instructions; The processor is configured to implement the aforementioned closed-loop control method for the surface density of a battery double-layer coating based on multispectral rays when executing executable instructions.

[0016] Compared with existing technologies, this invention breaks through the limitations of traditional single-layer coating models. By using dual-source collaborative acquisition and solving the ray attenuation equation system, it achieves accurate acquisition of the independent areal densities of the first and second coating layers in various battery double-layer coating processes. This completely solves the problem that existing technologies cannot distinguish the independent contributions of the upper and lower coating layers to the total areal density, significantly improving the consistency of coating ratios. By constructing a closed-loop control logic of "data acquisition - equation solving - speed adjustment," the operating speed of the slurry delivery unit is dynamically adjusted based on the real-time monitoring of the layer density and target deviation, effectively avoiding defects such as poor consistency between coating layers and insufficient electrode structure stability, ensuring the uniformity of electrode quality. Furthermore, without the need to separate coatings or perform offline sampling, online synchronous monitoring of the areal densities of the first and second coating layers is achieved by acquiring transmission data from the other side of the substrate. This reduces slurry waste and coating scrap rate, significantly improving production efficiency and the stability of large-scale production, meeting the production requirements of high-energy-density, high-quality batteries. Attached Figure Description

[0017] Figure 1 This is a flowchart of a closed-loop control method for the surface density of a battery double-layer coating based on multispectral X-rays, according to an embodiment of the present invention. Figure 2 This is a block diagram of a closed-loop control device for the surface density of a battery double-layer coating based on multispectral X-rays, according to an embodiment of the present invention. Detailed Implementation

[0018] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0019] Example 1 Based on the technical problems highlighted in the background, this embodiment proposes a closed-loop control method for the surface density of double-layer coating in batteries using multispectral X-rays. This method is applicable not only to lithium-ion batteries but also to sodium-ion batteries, solid-state batteries, and all other electrochemical energy storage batteries involving double-layer coating processes. It can universally achieve independent monitoring and closed-loop control of the front and back sides in scenarios where double-layer coating is performed on both sides of the substrate, such as single-sided double-layer coating. Figure 1 As shown, it includes: S1, a first ray source and a second ray source are arranged along the width direction of the substrate, and the first ray and the second ray are emitted to the double-coated surface on one side of the substrate, respectively, and the first transmission data and the second transmission data are collected from the other side of the substrate opposite to the double-coated surface. S2, based on the attenuation coefficients of the first coating, the second coating, and the substrate structure obtained through prior experimental calibration, construct a set of ray attenuation equations corresponding to the first ray and the second ray based on the principle of ray attenuation; S3, based on the first transmission data and the second transmission data, solve the ray attenuation equation set to obtain the areal density of the first coating and the areal density of the second coating; S4. Based on the areal density of the first coating and the areal density of the second coating, the operating speed of the slurry conveying unit is adjusted according to the target deviation controlled by the areal density.

[0020] In this embodiment, the substrate is a metal current collector foil of a battery electrode sheet, serving as the carrier substrate for the double-layer coating. It is an inherent component of the battery electrode sheet, and its material, thickness, and areal density are known fixed values ​​before coating and remain unchanged during coating and testing. The second coating refers to the lower coating applied first to the same side surface of the substrate, and the first coating refers to the upper coating applied later to the surface of the second coating. Together, they constitute a double-layer coating structure on one side of the substrate. This definition applies regardless of whether the substrate is double-coated on only one side or both sides. To obtain the independent areal densities of the first and second coatings, a first X-ray source and a second X-ray source are arranged along the width direction of the substrate at the winding position of the double-layer coating machine. The first X-ray source is... The first source is a ray with an energy range of 0.1-0.5 MeV, and the second source is an X-ray with an energy range of 5-20 keV. The lateral distance L between the two sources is set to 0.05-0.2 m.

[0021] The attenuation coefficients of the substrate structure, the second coating, and the first coating were obtained through prior experimental calibration. Based on the principle of ray attenuation, a system for determining the attenuation coefficients of the substrate structure, the second coating, and the first coating was established. The dual-ray attenuation equations for X-rays and gamma rays. Based on these equations, when the first and second rays irradiate the current double-coated surface, corresponding first and second transmission data are collected from the opposite side of the substrate. The first transmission data refers to... X-ray transmission data, the second transmission data refers to X-ray transmission data, according to Solving the dual-ray attenuation equations using X-ray transmission data and X-ray transmission data yields the areal density of the second coating and the areal density of the first coating.

[0022] The areal density of the second coating and the areal density of the first coating are fed back to the servo driver of the second coating and the servo driver of the first coating. Each servo driver adjusts the operating speed of the corresponding slurry conveying unit according to the areal density of the first coating and the second coating and the target deviation of the areal density control.

[0023] Preferably, the substrate structure is a pure substrate; based on the attenuation coefficients of the first coating, the second coating, and the substrate obtained through prior experimental calibration, and based on the principle of ray attenuation, a set of ray attenuation equations corresponding to the first ray and the second ray is constructed, including: A standard sample is prepared, wherein the standard sample is the substrate, and a second coating and a first coating are sequentially provided on one side surface of the substrate; The first and second rays were used to irradiate the double-layer coated surface of the standard sample, and the first calibration transmission data and the second calibration transmission data were measured. The thicknesses of the first coating, the second coating, and the substrate are measured. Based on the principle of radiation attenuation, the attenuation coefficients of the first coating, the second coating, and the substrate corresponding to the first and second rays are calculated according to the first and second calibration transmission data, respectively. A coefficient matrix is ​​established based on the attenuation coefficients. Based on the coefficient matrix and the principle of ray attenuation, a set of ray attenuation equations corresponding to the first ray and the second ray is constructed.

[0024] In the single-sided double-layer coating scenario, the substrate structure is a pure substrate with no coating on its surface, and its areal density is a pre-calibrated known value. The experimental calibration process includes preparing a standard sample. The standard sample is a substrate with the same structure as the actual double-layer coated electrode, with the second coating and the first coating sequentially applied to the same surface. In this embodiment, the substrate positive electrode uses aluminum foil with a thickness ranging from 10µm to 15µm, a typical value of 13µm, and an areal density of 0.356±0.0148g / 100cm³. 2 The negative electrode uses copper foil with a thickness ranging from 5µm to 8µm, typically 6µm, and an areal density of 0.535±0.016g / 100cm³. 2 Furthermore, the same surface of the substrate is sequentially coated with a second coating and a first coating. The thickness of the standard sample is measured, specifically including the thickness of the first coating d1, the thickness of the second coating d2, and the thickness of the substrate d. s .use The standard sample was irradiated with X-rays and X-rays respectively, and the first calibration transmission data and the second calibration transmission data were measured. The first calibration transmission data refers to... The first calibration transmission data refers to the X-ray calibration transmission data. Based on the calibration transmission data, the attenuation coefficient of each layer is calculated. The attenuation coefficient of the first coating layer includes... X-ray attenuation coefficient and X-ray attenuation coefficient The attenuation coefficient of the second coating includes X-ray attenuation coefficient and X-ray attenuation coefficient and the attenuation coefficient of the substrate, including X-ray attenuation coefficient and X-ray attenuation coefficient .

[0025] Establish containing , , , , , The coefficient matrix, based on the principle of ray attenuation, is established as follows regarding... The two-ray attenuation equations for X-rays and gamma rays:

[0026]

[0027] in, for Intensity after X-ray transmission The intensity after X-ray transmission. for Initial intensity of the radiation The initial intensity of the X-rays. The surface density of the first coating. The surface density of the second coating. The areal density of the known pure substrate is given.

[0028] By preparing a standard sample consistent with the actual coating structure, and combining the principle of ray attenuation to calibrate the attenuation coefficients of the corresponding dual rays for each layer and establish a coefficient matrix, we can provide accurate parameter support for the construction of the ray attenuation equation set, avoid the error in the areal density calculation caused by inaccurate attenuation coefficients, further improve the detection accuracy of the layered density, and ensure the reliability and stability of the equation set solution results.

[0029] Preferably, the substrate structure is a substrate that has already undergone double-layer coating on the other side; Based on the attenuation coefficients of the first coating, the second coating, and the substrate structure obtained through prior experimental calibration, and based on the principle of ray attenuation, a set of ray attenuation equations corresponding to the first ray and the second ray is constructed, including: Prepare a standard sample, wherein the standard sample is a substrate that has been double-coated on one side, and a second coating and a first coating are sequentially applied to the opposite side surface; The first and second rays are used to irradiate the double-layer coated surface on the other side, and the corresponding first calibration transmission data and second calibration transmission data are measured. The overall thickness of the first coating, the second coating, and the substrate structure is measured. Based on the principle of ray attenuation, the attenuation coefficients of the first coating, the second coating, and the substrate structure corresponding to the first ray and the second ray are calculated according to the first calibration transmission data and the second calibration transmission data. A coefficient matrix is ​​established based on the attenuation coefficients. Based on the coefficient matrix and the principle of ray attenuation, a set of ray attenuation equations corresponding to the first ray and the second ray is constructed.

[0030] When applying a double-layer coating to the opposite side of a substrate after a double-layer coating has been completed on one side, the substrate structure consists of the substrate and the completed double-layer coating on the other side. Taking the completed double-layer coating on the other side as the front of the substrate as an example, it is now necessary to control the areal density of the double-layer coating on the back of the substrate. To avoid calculation errors caused by differences in the slurry or thickness between the front and back sides, a standard template needs to be prepared. In this case, the standard template has a double-layer coating completed on the front side of the substrate, and a second coating and a first coating are sequentially applied on the back side of the substrate. The thickness of the standard template is measured, specifically including the thickness of the first coating d3, the thickness of the second coating d4, and the overall thickness of the substrate structure d. w .use The standard sample was irradiated with X-rays and X-rays respectively, and the first calibration transmission data and the second calibration transmission data were measured. The first calibration transmission data refers to... The first calibration transmission data refers to the X-ray calibration transmission data. Based on the calibration transmission data, the attenuation coefficient of each layer is calculated. The attenuation coefficient of the first coating layer includes... X-ray attenuation coefficient and X-ray attenuation coefficient The attenuation coefficient of the second coating includes X-ray attenuation coefficient and X-ray attenuation coefficient and the attenuation coefficient of the substrate structure, including X-ray attenuation coefficient and X-ray attenuation coefficient .

[0031] Establish containing , , , , , The coefficient matrix, based on the principle of ray attenuation, is established as follows regarding... The two-ray attenuation equations for X-rays and gamma rays:

[0032]

[0033] in, for Intensity after X-ray transmission The intensity after X-ray transmission. for Initial intensity of the radiation The initial intensity of the X-rays. The surface density of the first coating. The surface density of the second coating. The known surface density of the substrate structure.

[0034] Preferably, the ray attenuation equations are solved using the least squares method or a nonlinear fitting method to obtain the areal density of the first coating and the areal density of the second coating.

[0035] This embodiment involves data collection. After obtaining X-ray transmission data, the dual-ray attenuation equations are solved using the least squares method or nonlinear fitting method.

[0036]

[0037] Based on the above calculations, the areal density of the first coating and the areal density of the second coating are obtained in real time.

[0038] Similarly, when the substrate structure is a material that has already undergone double-layer coating on the other side, during the sampling... After obtaining X-ray transmission data, the dual-ray attenuation equations are solved using the least squares method or nonlinear fitting method.

[0039]

[0040] Based on the above calculations, the areal density of the first coating and the areal density of the second coating can be obtained in real time. Using this method, the areal density of each layer of coating on both sides of the substrate can be calculated.

[0041] The least squares method or nonlinear fitting method can be used to solve the ray attenuation equation system. Both methods have mature mathematical theoretical support and can efficiently handle the problem of solving dual-ray transmission data and multivariate attenuation equations. They can quickly and accurately obtain the independent areal density of the first and second coatings, balancing the solution efficiency and accuracy, and adapting to the real-time control requirements of coating production lines.

[0042] Preferably, the operating speed of the slurry conveying unit is adjusted based on the areal density of the first coating and the areal density of the second coating, controlling the target deviation based on the areal density, including: The areal density of the first coating is fed back to the servo driver of the slurry delivery unit corresponding to the first coating, and the areal density of the second coating is fed back to the servo driver of the slurry delivery unit corresponding to the second coating. The servo driver adjusts the operating speed of the corresponding slurry conveying unit according to the target deviation of the first coating surface density, the target surface density of the first coating, the target deviation of the second coating surface density, the target surface density of the second coating, and the total surface density constraint of the current double-layer coating.

[0043] The target deviation for the surface density of the first coating is ±1.5%, and the target deviation for the surface density of the second coating is ±1.0%. The total surface density constraint for the current double-layer coating is between the minimum and maximum total surface density. Taking a minimum total surface density of 170 g / m² and a maximum total surface density of 230 g / m² as an example, the final total surface density after coating must be greater than 170 g / m² and less than 230 g / m².

[0044] In the control system for double coating, each coating layer has an independent servo driver. After obtaining the areal density of the first coating layer and the areal density of the second coating layer in real time, the areal density of the first coating layer is fed back to the servo driver controlling the first coating slurry delivery unit, and the areal density of the second coating layer is fed back to the servo driver controlling the second coating slurry delivery unit. The servo driver is controlled by the control algorithm to precisely adjust the operating speed of the slurry delivery unit.

[0045] By feeding back the surface density of each layer to the servo drive of the corresponding slurry delivery unit, the independent adjustment of the slurry delivery for the first and second coating layers is achieved. At the same time, the total surface density constraint of the current double coating layer is introduced. Under the premise of ensuring that the surface density of each layer meets the deviation requirements, the total surface density is prevented from exceeding the process threshold, forming a dual guarantee of precise control of each layer and total surface density as a safety net, further optimizing the stability of coating quality and process adaptability.

[0046] Preferably, it further includes: Calculate the ratio of the areal density of the second coating to the areal density of the first coating; Calculate the absolute value of the deviation between the ratio and the preset ratio; Based on the absolute value of the deviation and the duration of the absolute value of the deviation, it is determined whether an interlayer mixing defect has occurred; In cases where interlayer mixing defects are determined to occur, the defect location and duration are marked based on the substrate conveyor speed and data acquisition timestamp. The defect location, duration, and ratio are fed back to the corresponding servo driver to adjust the operating speed of the corresponding slurry conveying unit.

[0047] This embodiment not only adjusts the operating speed of the corresponding slurry conveying unit based on the areal density of each coating layer to meet the areal density target deviation and the total areal density constraint of the current double-layer coating, but also includes judging whether there are defects based on the actual mixing ratio. Specifically, it uses the areal density of the first coating layer as a reference. =120g / m² and the surface density of the second coating Taking a density of 160 g / m² as an example, calculate the ratio of the areal density of the second coating to the areal density of the first coating. This can be recorded as the actual ratio and the preset ratio. Compare and calculate the absolute value of the deviation between the actual ratio and the preset ratio. It should be noted that the preset ratio can be changed according to actual needs. In this embodiment, the absolute value threshold of the deviation is set to 0.05, and the time threshold is set to 5 seconds. If the value is less than 0.05, the current double-layer coating process is considered normal and no marking signal is triggered.

[0048] Then, based on the areal density of the first coating... =110g / m², surface density of the second coating =150g / m² and preset ratio as an example For example, calculate the ratio. , compared with the preset ratio Comparison, absolute value of deviation If the deviation is greater than 0.05 and the duration of the deviation is greater than 5 seconds, an interlayer mixing defect is determined to have occurred.

[0049] After determining that an interlayer mixed defect has occurred, the control system triggers a marker signal to record the defect location and duration. The defect recording takes into account not only the substrate conveyor speed v (in m / s) and the data acquisition timestamp t (in seconds), but also the defect determination start time t. start and end time t end It is also necessary to consider the distance D (in meters) between the detector installation location and the coating head, the defect judgment delay time Δt, and the distance L between the marking device installation location and the detector. m The actual location P(t) of the defect on the substrate can be calculated using the following formula: Where t0 is the coating start time, the substrate conveyor speed v can be obtained in real time through the encoder, and the distance D is used to correct the deviation between the detection position and the actual coating position. Furthermore, physical marking is required at the marking device, such as inkjet printing or punching, and the distance L between the marking device and the detector also needs to be considered. m Mark the trigger time t mark for: .

[0050] For example, assume the substrate conveyor speed is v = 0.5 m / s; the distance between the detector and the coating head is D = 1.2 m; and the distance between the marking device and the detector is L. m =0.3m; Defect judgment start time t start =10:00:05 (5 seconds after coating begins), defect judgment end time t end =10:00:10; sampling frequency is 500Hz, and timestamp accuracy is 2ms.

[0051] Calculate the defect initiation location (relative to the coating start point): P start =0.5×5+1.2=3.7m; Defect termination location calculation: P end =0.5×10+1.2=6.2m; The marking trigger time of the marking device: t mark =10:00:05+0.3 / 0.5=10:00:05.6; At this time, the control system will mark the interlayer mixing defect area on the substrate within the range of 3.7m to 6.2m relative to the coating start point, and trigger the marking device at 10:00:05.6 to perform physical marking, such as inkjet printing, punching, labeling, etc., to facilitate subsequent rejection or re-inspection.

[0052] The defect location, duration, and actual mixing ratio are fed back to the corresponding servo drive. For example, if the defect is caused by a deviation in the first coating mixing ratio, the feedback is sent to the servo drive controlling the first coating slurry delivery unit. This precisely adjusts the operating speed of the slurry delivery unit so that the absolute value of the deviation is less than 0.05, and the areal density of each coating layer meets the corresponding target deviation and the total areal density constraint of the current double-layer coating. In this embodiment, the servo drive uses an incremental PID control algorithm as the core control strategy, expressed as:

[0053] Where Δu(k) is the control increment at the current moment, representing the speed adjustment of the slurry conveying unit; e(k) is the surface density deviation at the current moment; K p K i K d These are the proportional, integral, and derivative coefficients, respectively; the control period Ts is set to 0.1s to match the detector sampling frequency.

[0054] The areal density of the first coating and the areal density of the second coating are respectively fed back to the servo drive of the slurry delivery unit. In each control cycle, the deviation e(k) is calculated, and Δu(k) is calculated. The rotation speed is adjusted according to the target deviation of the areal density control. Taking the slurry delivery unit of the first coating as a screw pump and adjusting its rotation speed as an example, assuming the target areal density of the first coating... ref =120g / m 2 The current measured surface density of the first coating is meas =118g / m 2 Deviation e(k) = -2g / m 2 Previous cycle deviation e ( k- 1) = -1.5g / m 2 Previous cycle deviation e ( k- 2) = -1g / m 2 Control coefficient K p K i K d Initial settings can be achieved using the Ziegler-Nichols tuning method or other self-tuning methods, followed by fine-tuning through step response testing to ensure the control system has a fast response speed, small overshoot, and small steady-state error. Here, the control coefficient K is used as an example. p =0.5, K i =0.1, K d For example, if the value is 0.05, then: Δu(k)=0.5×[-2-(-1.5)]+0.1×(-2)+0.05×[-2-2×(-1.5)+(-1)]; Δu(k)=0.5×(-0.5)+0.1×(-2)+0.05×[-2+3-1]; Δu(k)=-0.25-0.2+0.05×0=-0.45; This means that the screw pump speed for the first coating layer needs to be reduced by 0.45% relative to the current speed in order to increase the areal density to the target value.

[0055] By combining the areal density ratio and deviation duration, interlayer mixing defects are accurately identified. Defect location is achieved based on substrate conveyor speed and data timestamps. Defect information is fed back to the servo driver for targeted adjustment. This not only promptly curbs defect expansion but also provides data support for subsequent quality traceability and process optimization, further reducing scrap rate and improving the quality control level of the production process.

[0056] Preferably, a scintillator detector array is arranged along the width direction of the substrate to collect a first ray transmission intensity sequence and a second ray transmission intensity sequence from the other side of the substrate opposite the double-coated surface. The first X-ray transmission intensity sequence and the second X-ray transmission intensity sequence are converted from data to data to obtain the first transmission data and the second transmission data.

[0057] This embodiment uses a scintillator detector array arranged along the width of the substrate to simultaneously acquire data from the other side of the substrate opposite the double-coated surfaces. X-ray transmission intensity sequence and X-ray transmission intensity sequence The transmission intensity data collected by the detector array is converted from digital signal to digital signal to digital signal. X-ray transmission data and X-ray transmission data are collected and stored in a data memory. The detector array has a lateral resolution of ≤5mm and a sampling frequency of ≥500Hz.

[0058] The detector array is arranged along the width of the substrate, enabling full-width, blind-spot-free acquisition. Furthermore, the digitally processed transmission data is easier to solve and store in subsequent equations, improving the comprehensiveness, accuracy, and compatibility of data acquisition and laying the hardware data foundation for real-time online monitoring.

[0059] Preferably, the first ray is The first ray is X-ray, and the second ray is X-ray.

[0060] The two types of radiation have complementary attenuation characteristics: X-rays are sensitive to thin coatings, and X-rays have stronger penetrating power. The combination of the two can fully adapt to the structural characteristics of double coatings, effectively distinguish the attenuation differences between the first coating, the second coating and the substrate structure, avoid the problem of single-ray analysis being difficult, and provide reliable X-ray technology support for layer density calculation.

[0061] Preferably, the slurry delivery unit is a screw pump, and the servo driver controls the delivery amount of the corresponding coating slurry by adjusting the rotational speed of the screw pump.

[0062] In this embodiment, the slurry delivery unit is specifically a screw pump. The servo driver adjusts the speed of the screw pump to control the delivery volume of the corresponding coating slurry. The screw pump has the characteristic of constant volume delivery, and the speed and delivery volume have a precise linear relationship. It can realize fine adjustment of the slurry delivery volume, ensure rapid correction of areal density deviation, further improve the response speed and adjustment accuracy of closed-loop control, and adapt to the high-requirement double-layer coating process.

[0063] This embodiment overcomes the limitations of traditional single-layer coating models by employing the above methods. Through dual-source collaborative acquisition and solving of the ray attenuation equations, it achieves precise acquisition of the independent areal densities of the first and second coating layers in various battery double-layer coating processes. This completely solves the problem of existing technologies being unable to distinguish the independent contributions of the upper and lower coating layers to the total areal density, significantly improving the consistency of coating ratios. By constructing a closed-loop control logic of "data acquisition - equation solving - speed adjustment," the operating speed of the slurry delivery unit is dynamically adjusted based on real-time monitoring of the layered areal densities and target deviations, effectively avoiding defects such as poor consistency between coating layers and insufficient electrode structural stability, ensuring the uniformity of electrode quality. Furthermore, without the need for coating splitting or offline sampling, online synchronous monitoring of the areal densities of the first and second coating layers is achieved by acquiring transmission data from the other side of the substrate. This reduces slurry waste and coating scrap rates, significantly improving production efficiency and the stability of large-scale production, meeting the production requirements of high-energy-density, high-quality batteries.

[0064] Example 2 Furthermore, based on the principles described in Example 1, a closed-loop control device 100 for the surface density of a battery double-layer coating based on multispectral X-rays is proposed, such as... Figure 2 As shown, it includes: The X-ray mounting and emission module 110 is used to arrange the first X-ray source and the second X-ray source along the width direction of the substrate, and emit the first X-ray and the second X-ray respectively onto the double-coated surface on one side of the substrate; The X-ray data acquisition module 120 is used to acquire first transmission data and second transmission data from the other side of the substrate opposite the double-coated surface. The equation construction module 130 is used to construct the ray attenuation equation set corresponding to the first ray and the second ray based on the ray attenuation principle, according to the attenuation coefficients of the first coating, the second coating and the substrate structure obtained in advance through experimental calibration. The areal density calculation module 140 is used to solve the ray attenuation equation set according to the first transmission data and the second transmission data to obtain the areal density of the first coating and the areal density of the second coating. The control module 150 is used to adjust the operating speed of the slurry conveying unit based on the areal density of the first coating and the areal density of the second coating, and to control the target deviation based on the areal density.

[0065] Example 3 Furthermore, an electronic device is proposed, comprising: processor; Memory used to store processor-executable instructions; The processor is configured to implement, when executing executable instructions, a closed-loop control method for the surface density of a battery double-layer coating based on multispectral rays, as described in Embodiment 1.

[0066] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0067] Furthermore, it should be noted that the use of terms such as "first," "second," and "a" in this invention is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified. The terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two elements or the interaction between two elements, unless otherwise explicitly specified. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0068] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0069] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A closed-loop control method for the surface density of a double-layer coating in a battery based on multispectral X-rays, characterized in that, include: A first radiation source and a second radiation source are arranged along the width direction of the substrate to emit the first radiation and the second radiation onto the double-coated surface on one side of the substrate, respectively, and to collect the first transmission data and the second transmission data from the other side of the substrate opposite the double-coated surface. Based on the attenuation coefficients of the first coating, the second coating, and the substrate structure obtained through prior experimental calibration, a set of ray attenuation equations corresponding to the first ray and the second ray is constructed based on the principle of ray attenuation. Based on the first transmission data and the second transmission data, the corresponding ray attenuation equations are solved to obtain the areal density of the first coating and the areal density of the second coating. Based on the areal density of the first coating and the areal density of the second coating, the operating speed of the slurry conveying unit is adjusted according to the target deviation controlled by the areal density.

2. The method according to claim 1, characterized in that, The substrate structure is a pure substrate; Based on the attenuation coefficients of the first coating, the second coating, and the substrate, obtained through prior experimental calibration, and based on the principle of ray attenuation, a set of ray attenuation equations corresponding to the first ray and the second ray is constructed, including: A standard sample is prepared, wherein the standard sample is the substrate, and a second coating and a first coating are sequentially provided on one side surface of the substrate; The first and second rays were used to irradiate the double-layer coated surface of the standard sample, and the first calibration transmission data and the second calibration transmission data were measured. The thicknesses of the first coating, the second coating, and the substrate are measured. Based on the principle of radiation attenuation, the attenuation coefficients of the first coating, the second coating, and the substrate corresponding to the first and second rays are calculated according to the first and second calibration transmission data, respectively. A coefficient matrix is ​​established based on the attenuation coefficients. Based on the coefficient matrix and the principle of ray attenuation, a set of ray attenuation equations corresponding to the first ray and the second ray is constructed.

3. The method according to claim 1, characterized in that, The substrate structure is a substrate that has been double-coated on the other side; Based on the attenuation coefficients of the first coating, the second coating, and the substrate structure obtained through prior experimental calibration, and based on the principle of ray attenuation, a set of ray attenuation equations corresponding to the first ray and the second ray is constructed, including: Prepare a standard sample, wherein the standard sample is a substrate that has been double-coated on one side, and a second coating and a first coating are sequentially applied to the opposite side surface; The first and second rays are used to irradiate the double-layer coated surface on the other side, and the corresponding first calibration transmission data and second calibration transmission data are measured. The overall thickness of the first coating, the second coating, and the substrate structure is measured. Based on the principle of ray attenuation, the attenuation coefficients of the first coating, the second coating, and the substrate structure corresponding to the first ray and the second ray are calculated according to the first calibration transmission data and the second calibration transmission data. A coefficient matrix is ​​established based on the attenuation coefficients. Based on the coefficient matrix and the principle of ray attenuation, a set of ray attenuation equations corresponding to the first ray and the second ray is constructed.

4. The method according to claim 1, characterized in that, The ray attenuation equations are solved using the least squares method or a nonlinear fitting method to obtain the areal density of the first coating and the areal density of the second coating.

5. The method according to claim 1, characterized in that, Based on the areal density of the first coating and the areal density of the second coating, and controlling the target deviation based on the areal density, the operating speed of the slurry conveying unit is adjusted, including: The areal density of the first coating is fed back to the servo driver of the slurry delivery unit corresponding to the first coating, and the areal density of the second coating is fed back to the servo driver of the slurry delivery unit corresponding to the second coating. The servo driver adjusts the operating speed of the corresponding slurry conveying unit according to the target deviation of the first coating surface density, the target surface density of the first coating, the target deviation of the second coating surface density, the target surface density of the second coating, and the total surface density constraint of the current double-layer coating.

6. The method according to claim 5, characterized in that, Also includes: Calculate the ratio of the areal density of the second coating to the areal density of the first coating; Calculate the absolute value of the deviation between the ratio and the preset ratio; Based on the absolute value of the deviation and the duration of the absolute value of the deviation, it is determined whether an interlayer mixing defect has occurred; In cases where interlayer mixing defects are determined to occur, the defect location and duration are marked based on the substrate conveyor speed and data acquisition timestamp. The location, duration, and ratio of the defect are fed back to the corresponding servo driver to adjust the operating speed of the corresponding slurry conveying unit.

7. The method according to claim 1, characterized in that, A scintillator detector array is arranged along the width direction of the substrate to collect a first ray transmission intensity sequence and a second ray transmission intensity sequence from the other side of the substrate opposite the double-coated surface. The first X-ray transmission intensity sequence and the second X-ray transmission intensity sequence are converted from data to data to obtain the first transmission data and the second transmission data.

8. The method according to claim 1, characterized in that, The first ray is a beta ray, and the second ray is an X-ray.

9. A closed-loop control device for the surface density of a battery double-layer coating based on multispectral X-rays, characterized in that, include: The X-ray mounting and emission module is used to arrange the first X-ray source and the second X-ray source along the width direction of the substrate, and emit the first X-ray and the second X-ray respectively onto the double-coated surface on one side of the substrate; A radiation data acquisition module is used to acquire first transmission data and second transmission data from the other side of the substrate opposite the double-coated surfaces. The equation system module is used to construct the ray attenuation equation system corresponding to the first ray and the second ray based on the ray attenuation principle, according to the attenuation coefficients of the first coating, the second coating and the substrate structure obtained through experimental calibration in advance. The areal density calculation module is used to solve the ray attenuation equation set according to the first transmission data and the second transmission data to obtain the areal density of the first coating and the areal density of the second coating. The control module is used to adjust the operating speed of the slurry conveying unit based on the areal density of the first coating and the areal density of the second coating, and to control the target deviation based on the areal density.

10. An electronic device, characterized in that, include: processor; Memory used to store processor-executable instructions; The processor is configured to implement, when executing executable instructions, a closed-loop control method for the surface density of a battery double-layer coating based on multispectral rays as described in any one of claims 1-8.

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