A method and system for closed loop control of coating area density

Abstract

The present application belongs to the technical field of battery production, and particularly relates to a coating surface density closed-loop control method and system. The method comprises the following steps: obtaining the coating surface density of the dried current collector in real time, wherein the coating surface density comprises a large unit surface density and a small unit surface density; calculating the deviation between the real-time coating surface density and a target coating surface density, and judging whether the coating surface density is qualified according to the density deviation; if not, calculating the adjustment instruction of the coating machine according to the correlation between the coating machine parameters and the coating surface density; and adjusting the coating pump speed and / or the angle of the die micrometer knob of the coating machine according to the adjustment instruction to realize the surface density control in the coating process. The present application adjusts the longitudinal surface density of the film area by adjusting the die pump speed, and adjusts the transverse surface density of the film area by adjusting the angle of the die micrometer, thereby improving the consistency of the coating density.

Description

Technical Field

[0001] This invention belongs to the field of battery manufacturing technology, and in particular relates to a closed-loop control method and system for coating surface density. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] In the production of new energy power batteries, coating areal density refers to the density at which a mixture of electrode materials is coated onto the electrode current collector. In lithium-ion batteries, coating areal density is one of the important parameters affecting battery performance and lifespan. Different coating areal densities have a direct impact on the composition and microstructure of the electrode materials.

[0004] The consistency of coating surface density in the horizontal and vertical directions is an important indicator for evaluating the quality of the film. The process of coating fluid onto the surface of the current collector cannot be recorded manually. The current method is to adjust the parameters of the coating machine manually in conjunction with the data of the surface density meter. However, the manual adjustment method is not precise enough and requires a high level of personnel skill.

[0005] Currently, industry technology typically improves the longitudinal surface density of the membrane zone by controlling the chamber pressure, and usually adjusts the wet membrane surface density. However, due to the poor consistency of slurry moisture content, the calculated K value may have a large deviation (the K value is used to characterize the linear relationship between surface density and equipment parameters), affecting the adjustment accuracy. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, the present invention provides a closed-loop control method and system for coating surface density.

[0007] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions:

[0008] The first aspect of this invention provides a closed-loop control method for coating surface density, comprising:

[0009] The surface density of the current collector after drying is obtained in real time, and the surface density of the coating includes the surface density of large unit cells and the surface density of small unit cells;

[0010] Calculate the deviation between the real-time coating surface density and the target coating surface density, and determine whether the coating surface density is qualified based on the density deviation; if not, calculate the adjustment command of the coating machine based on the correlation between the coating machine parameters and the coating surface density.

[0011] Adjust the coating pump speed and / or the micrometer knob angle of the die head according to the adjustment instructions to achieve surface density control during the coating process.

[0012] A second aspect of the present invention provides a closed-loop control system for coating surface density, comprising:

[0013] The data acquisition module is configured to: acquire the coating surface density of the current collector unit in real time, wherein the coating surface density includes the surface density of large unit and the surface density of small unit;

[0014] The density deviation calculation module is configured to: calculate the deviation between the real-time coating surface density and the target coating surface density, and determine whether the coating surface density is qualified based on the density deviation;

[0015] The coating machine adjustment command calculation module is configured to: if not, calculate the coating machine adjustment command based on the relationship between the coating machine parameters and the coating surface density;

[0016] The coating machine parameter real-time adjustment module is configured to adjust the coating pump speed and / or the die head micrometer knob angle of the coating machine according to the adjustment command, so as to achieve the surface density control of the coating process.

[0017] A third aspect of the present invention provides a computer-readable storage medium having a program stored thereon that, when executed by a processor, implements the steps of a closed-loop control method for coating surface density as described in the first aspect of the present invention.

[0018] A fourth aspect of the present invention provides an electronic device including a memory, a processor, and a program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of a closed-loop control method for coating surface density as described in the first aspect of the present invention.

[0019] The above one or more technical solutions have the following beneficial effects:

[0020] (1) The present invention adjusts the longitudinal surface density of the film area by adjusting the pump speed of the die head, and adjusts the transverse surface density of the film area by adjusting the micrometer angle of the die head, thereby improving the consistency of coating density; and by using the dry film surface density to calculate the K value used to characterize the relationship between surface density and equipment parameters, the problem of large deviation in the calculated K value caused by the existing wet film surface density, which affects the adjustment accuracy, is solved.

[0021] (2) The closed-loop control method for coating surface density provided by the present invention effectively enhances the automation capability of the coating process. At the same time, it reduces the problem of batch defects in the coating surface caused by employees incorrectly changing equipment parameters during the coating process, and strengthens the error prevention and foolproof capability of the coating process.

[0022] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0023] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0024] Figure 1 This is a flowchart of a closed-loop control method for coating surface density according to the first embodiment.

[0025] Figure 2 This is a schematic diagram of the substrate coating surface in the first embodiment.

[0026] Figure 3 This is a structural diagram of a closed-loop control system for coating surface density according to the second embodiment.

[0027] Figure 4 This is a structural diagram of the pump head system in the second embodiment. Detailed Implementation

[0028] Example 1

[0029] like Figure 1 As shown, this embodiment discloses a closed-loop control method for coating surface density, including:

[0030] Step 1: Obtain the coating surface density of the current collector after drying in real time. The coating surface density includes the large unit surface density and the small unit surface density.

[0031] Step 2: Calculate the deviation between the real-time coating surface density and the target coating surface density, and determine whether the coating surface density is qualified based on the density deviation; if not, calculate the adjustment command of the coating machine based on the correlation between the coating machine parameters and the coating surface density.

[0032] Step 3: Adjust the coating pump speed and / or the micrometer knob angle of the coating machine according to the adjustment instructions to achieve the area density control during the coating process.

[0033] In step 1, when the current collector is coated on both sides, the surface density of the upper coating and the surface density of the lower coating are obtained, and the adjustment commands of the coating machine on the corresponding side are adjusted according to the surface density of the upper coating and the surface density of the lower coating.

[0034] Step 101: Obtain the coating surface density of the current collector in real time using a surface density tester, including:

[0035] The areal density of the current collector, the areal density of the upper coating of the current collector (i.e., the areal density of side A), and the areal density of the double coating (i.e., the areal density of side AB) are obtained using an areal density tester; the difference between the areal density of the double coating and the areal density of the upper coating (i.e., the areal density of side A) is the areal density of the lower coating (i.e., the areal density of side B).

[0036] Step 102: The calculation method for areal density includes:

[0037] The surface of the substrate electrode is divided into several regions, and the area of ​​each region is obtained. The current collector surface density refers to the ratio of the current collector weight to the area in any given area.

[0038] The surface density of a double-coated layer refers to the ratio of the test weight of the double-sided coating to the area of ​​any given area, minus the surface density of the current collector.

[0039] Step 103: The surface density of each coating layer includes both large unit surface density and small unit surface density;

[0040] The surface density of a small unit is calculated based on the ratio of its weight to its area; the surface density of a large unit is calculated based on the average of the surface densities of multiple small units within the large unit.

[0041] like Figure 2 As shown, the current collector serves as the substrate, on which slurry is coated at equal intervals. The area on the current collector after the slurry is coated (the black area in the figure) is called a small unit 2; the area containing multiple small units with the same longitudinal spacing and transverse spacing on the current collector is called a large unit 1.

[0042] Large unit surface density ρ i The average surface density of a transverse row of regions when the coated electrode passes through the surface density meter; small unit density ρ ij The surface density of each region in the transverse direction when the coated electrode passes through the surface density instrument; small unit density ρ ij The average density of multiple sampling regions within each small unit.

[0043] Specifically: During the process of the current collector passing through the areal density testing instruments #1, #2, and #3, a region with the same longitudinal spacing on the current collector is taken as a large unit. The large unit is numbered as i, i = 1, 2, 3, ... N, where N is a positive integer. The current collector coating area with the same spacing in the transverse region of each large unit is taken as a small unit, denoted as j, j = 1, 2, 3, ... X, where X is a positive integer.

[0044] During normal operation, each current collector passes sequentially through surface density testers #1, #2, and #3. The area of ​​each collected unit is denoted as S. Therefore, the area of ​​a current collector unit with longitudinal dimension i and transverse dimension j as it passes through the surface density testers is denoted as S. ij ;

[0045] The weight of each small unit tested as it passed through the areal density testing instruments #1, #2, and #3 in sequence was recorded as G. ij1 G ij2 G ij3After obtaining the weight and area of ​​each small unit, the areal density of each small unit is calculated using the areal density calculation method from the previous step, generating four data files internally, representing the areal density ρ of the current collector. ij1 Surface density ρ of surface A ij2 Surface density ρ of AB surface ij3 and the surface density ρ of surface B ij4 ;

[0046] The surface density of surface B is obtained by subtracting the surface density of surface A from the surface density of surface AB; the average value of the coating surface density of each small unit within a large unit is taken as the representative value ρ of the large unit surface density. i .

[0047] In step 2, the deviation between the real-time coating surface density and the target coating surface density is calculated, and the coating surface density is judged to be qualified based on the density deviation; if not, the adjustment command of the coating machine is calculated based on the correlation between the coating machine parameters and the coating surface density.

[0048] Step 201: Determine whether the coating surface density is qualified based on the density deviation, including: if the deviation of the coating surface density is greater than the upper limit value, output the surface density too high command;

[0049] If the density deviation of the coating surface density is less than the lower limit, then output a low surface density command.

[0050] If the density deviation of the coating surface density is greater than or equal to the lower limit and less than or equal to the lower limit, then the surface density is output as qualified.

[0051] Specifically: (1) After collecting the corresponding large unit ρ i When processing data, compare it with the standard data value ρ0±β0, where β0 is the process tolerance. If ρ i If ρ0+β0, then the output is a high areal density command, which gives a new X value and outputs it to the command execution module. The command execution module controls the coating master to change a pump speed for adjustment.

[0052] If ρ i If the value is less than ρ0-β0, an output isa density too low command is given, a new X value is output to the command execution module, and the command execution module controls the coating master to change a pump speed for adjustment;

[0053] If ρ0 + β0 ≥ ρ i If ≥ρ0-β0, a qualified command is output, and the command module outputs to the coating control center without changing the pump speed;

[0054] (2) After obtaining the surface density ρ of surface A. ij2 When processing data, compare it with the standard input data values. For comparison, β represents the process tolerance. The output is a high surface density command, which gives a new N value and outputs it to the command execution module. The command execution module controls the micrometer controller of the coating A-side die head to rotate to the corresponding angle for adjustment.

[0055] like The output is a low surface density command, which gives a new N value and outputs it to the command execution module. The command execution module controls the micrometer controller of the coating A-side die head to rotate to the corresponding angle for adjustment.

[0056] like Then a qualified instruction is output, and the command module outputs to the micrometer controller of the coating A-side die head without modification;

[0057] (3) After obtaining the surface density ρ of surface B ij4 When processing data, compare it with the standard input data values. For comparison, β represents the process tolerance. The output is a high surface density command, which gives a new N value and outputs it to the command execution module. The command execution module controls the micrometer controller of the coating B-side die head to rotate to the corresponding angle for adjustment.

[0058] like The output is a low surface density command, which gives a new N value and outputs it to the command execution module. The command execution module controls the micrometer controller of the coating B-side die head to rotate to the corresponding angle for adjustment.

[0059] like If a qualified instruction is output, the command module outputs the instruction to the micrometer controller of the coating B-side die head, without making any changes.

[0060] Step 202: Based on the correlation between the coating machine parameters and the coating surface density, calculate the adjustment commands for the coating machine, including:

[0061] (1) Calculate the coating pump speed adjustment command based on the correlation between the density of large unit surfaces, the coating pump speed, and the net coating amount at the die head; specifically:

[0062] The coating amount of the coating slurry is positively correlated with the coating pump speed. The collected coating pump speed is used as the independent variable, defined as X, and the unit surface density is used as the dependent variable, defined as Y. After obtaining a certain amount of data, the linear relationship between the independent and dependent variables is obtained by linear regression, namely Y = K1X + b, where K1 is the system coefficient, which is calculated by fitting historical data, and b is the net coating amount of the die head when X = 0.

[0063] (2) Calculate the adjustment command for the micrometer knob based on the relationship between the surface density of the small unit and the knob angle of the micrometer.

[0064] Define the coating micrometer knob as decreasing the surface density when rotated downwards and increasing the surface density when rotated upwards. Position the 0 point when the knob is at its smallest angle (i.e., it cannot be rotated upwards any further). The micrometer rotation angle is defined as N, with the unit being °.

[0065] The coating amount of the coating slurry is inversely correlated with the knob angle of the coating micrometer. The collected knob angles of the coating micrometer are used as the independent variable, defined as N, and the small unit surface density is used as the dependent variable, defined as M. After obtaining a certain amount of data, the linear relationship between the independent and dependent variables is obtained by linear regression, i.e., M = K2N + C, where K2 is the system coefficient, which is calculated by fitting historical data, and C is the compensation value.

[0066] Example 2

[0067] This embodiment discloses a closed-loop control system for coating surface density, including:

[0068] The data acquisition module is configured to: acquire the coating surface density of the current collector after drying in real time, including the surface density of large units and the surface density of small units;

[0069] The data processing module includes:

[0070] The density deviation calculation module is configured to: calculate the deviation between the real-time coating surface density and the target coating surface density, and determine whether the coating surface density is qualified based on the density deviation;

[0071] The coating machine adjustment command calculation module is configured to: if not, calculate the coating machine adjustment command based on the relationship between the coating machine parameters and the coating surface density;

[0072] The coating machine parameter real-time adjustment module is configured to adjust the coating pump speed and / or the die head micrometer knob angle of the coating machine according to the adjustment command, so as to achieve the surface density control of the coating process.

[0073] Among them, the adjustment command of the coating machine is calculated based on the relationship between the coating machine parameters and the coating surface density, including: the coating pump speed adjustment command is calculated based on the relationship between the large unit surface density, the coating pump speed and the net coating amount of the die head.

[0074] Based on the correlation between the surface density of small units and the angle of the die head micrometer knob, the adjustment command for the die head micrometer knob angle is calculated.

[0075] Among them, judging whether the coating surface density is qualified based on the density deviation includes: if the deviation of the coating surface density is greater than the upper limit value, then outputting a surface density too high command.

[0076] If the density deviation of the coating surface density is less than the lower limit, output a low surface density command;

[0077] If the density deviation of the coating surface density is greater than or equal to the lower limit and less than or equal to the lower limit, then the surface density is output as qualified.

[0078] The data collected by the data acquisition module includes the coating pump speed, micrometer angle, and the surface density of the coated current collector, the surface density of the coating on one side, and the surface density of the coating on both sides measured by the surface density testing instrument, which correspond to the results of the surface density testing instruments for coating #1, #2, and #3, respectively.

[0079] The density deviation calculation module is used to process the data obtained by the data acquisition module, classify the data collected by the data acquisition module, and name them as current collector surface density, A-side surface density, and AB-side surface density, respectively, to obtain the prediction model of each region on the surface of the electrode substrate.

[0080] The coating machine adjustment command calculation module is used to analyze whether the required areal density of the electrode substrate meets the requirements based on the new areal density data obtained, and to generate the corresponding adjustment command if the requirements are not met.

[0081] like Figure 3 , Figure 4 As shown, the equipment used in the current collector slurry coating process includes: a winding device, a No. 1 surface density meter, an A coating machine, an A layer drying oven, a No. 2 surface density meter, a B coating machine, a B layer drying oven, and a No. 3 surface density meter.

[0082] The drying oven is used to dry the coated liquid electrode sheet into a solid electrode sheet. The micrometer is used to control the local output of the die head on the coating machine and to make adjustments in some areas. The winding equipment is used to wind the current collector / electrode sheet into a large roll similar to a steel coil.

[0083] The coating process of the current collector slurry is as follows:

[0084] The uncoated current collector is unwound using a winding device and then conveyed to a surface density meter (No. 1) for measuring its surface density. Next, the A-coating machine is used to coat the current collector's surface A with slurry. The coated current collector is then dried using an A-layer drying oven, and the surface density of the A-layer coating is measured using a surface density meter (No. 2). Then, the B-coating machine is used to coat the current collector's surface B with slurry, and the surface is dried using a B-layer drying oven. Finally, the surface density of the A and B coatings is measured using a surface density meter (No. 3).

[0085] Example 3

[0086] The purpose of this embodiment is to provide a computer-readable storage medium.

[0087] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of a closed-loop control method for coating surface density as described in Embodiment 1 of this disclosure.

[0088] Example 4

[0089] The purpose of this embodiment is to provide an electronic device.

[0090] An electronic device includes a memory, a processor, and a program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps in a closed-loop control method for coating surface density as described in Embodiment 1 of this disclosure.

[0091] The steps and methods involved in the apparatuses of Embodiments 2, 3, and 4 above correspond to those in Embodiment 1. For specific implementation details, please refer to the relevant description section of Embodiment 1. The term "computer-readable storage medium" should be understood as a single medium or multiple media including one or more instruction sets; it should also be understood as including any medium capable of storing, encoding, or carrying an instruction set for execution by a processor and enabling the processor to perform any of the methods in this invention.

[0092] Those skilled in the art will understand that the modules or steps of the present invention described above can be implemented using general-purpose computer devices. Optionally, they can be implemented using computer-executable program code, thereby allowing them to be stored in a storage device for execution by a computer device, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. The present invention is not limited to any particular combination of hardware and software.

[0093] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A closed-loop control method for coating surface density, characterized in that, include: The surface density of the current collector after drying is obtained in real time, and the surface density of the coating includes the surface density of large unit cells and the surface density of small unit cells; Calculate the deviation between the real-time coating surface density and the target coating surface density, and determine whether the coating surface density is qualified based on the density deviation: after collecting the corresponding large unit data... When processing data, compare it with standard data values. ± To make a comparison, To allow for process tolerances, if If the areal density is too high, an instruction will be output, providing a new value to the command execution module. The command execution module will then control the coating master to adjust the pump speed. If the areal density is too low, an instruction will be output, providing a new value to the command execution module. The command execution module will then control the coating master to adjust the pump speed. If the condition is met, a qualified command is output, and the command module outputs to the coating control center, without changing the pump speed; otherwise, the adjustment command for the coating machine is calculated based on the correlation between the coating machine parameters and the coating surface density. This includes calculating the coating pump speed adjustment command based on the correlation between the large unit surface density, the coating pump speed, and the net coating amount at the die head. The coating slurry coating amount is positively correlated with the coating pump speed. The collected coating pump speed is used as the independent variable and defined as... Using the unit surface density as the dependent variable, it is defined as follows: After obtaining a certain amount of data, linear regression is used to obtain the linear relationship between the independent and dependent variables. ,in These are system coefficients, calculated by fitting historical data. for Net coating amount at the mold head; It also includes: calculating the micrometer knob angle adjustment command based on the relationship between the surface density of small units and the knob angle of the die head micrometer; Adjust the coating pump speed and / or the micrometer knob angle of the die head according to the adjustment instructions to achieve surface density control during the coating process.

2. The closed-loop control method for coating surface density as described in claim 1, characterized in that, The method of determining whether the coating surface density is qualified based on the density deviation includes: if the deviation of the coating surface density is greater than the upper limit value, then outputting a surface density too high command. If the density deviation of the coating surface density is less than the lower limit, output a low surface density command; If the density deviation of the coating surface density is greater than or equal to the lower limit and less than or equal to the lower limit, then the surface density is output as qualified.

3. The closed-loop control method for coating surface density as described in claim 1, characterized in that, The surface density of a small unit is calculated based on the ratio of the weight of the lower unit to the area of ​​that unit, and the surface density of the large unit is calculated based on the average of the surface densities of multiple small units within the large unit.

4. The closed-loop control method for coating surface density as described in claim 1, characterized in that, The real-time acquisition of the coating surface density of the current collector after drying includes: When the current collector unit is coated on both sides, the surface density of the upper coating and the surface density of the lower coating are obtained. The surface density of each coating includes the surface density of the large unit and the surface density of the small unit. Adjust the corresponding side of the coating machine according to the surface density of the upper coating and the surface density of the lower coating.

5. A closed-loop control system for coating surface density, characterized in that, include: The data acquisition module is configured to: acquire the coating surface density of the current collector after drying in real time, wherein the coating surface density includes large unit surface density and small unit surface density; The density deviation calculation module is configured to: calculate the deviation between the real-time coating surface density and the target coating surface density, and determine whether the coating surface density is qualified based on the density deviation; after collecting the corresponding large unit data... When processing data, compare it with standard data values. ± To make a comparison, To allow for process tolerances, if If the areal density is too high, an instruction will be output, providing a new value to the command execution module. The command execution module will then control the coating master to adjust the pump speed. If the areal density is too low, an instruction will be output, providing a new value to the command execution module. The command execution module will then control the coating master to adjust the pump speed. If the condition is met, a qualified instruction will be output, and the command module will output to the coating control center without changing the pump speed. The coating machine adjustment command calculation module is configured to: if not, calculate the coating machine adjustment command based on the correlation between coating machine parameters and coating surface density, including calculating the coating pump speed adjustment command based on the correlation between large unit surface density, coating pump speed, and die head net coating amount: the coating slurry coating amount is positively correlated with the coating pump speed, and the collected coating pump speed is used as the independent variable, defined as... Using the unit surface density as the dependent variable, it is defined as follows: After obtaining a certain amount of data, linear regression is used to obtain the linear relationship between the independent and dependent variables. ,in These are system coefficients, calculated by fitting historical data. for Net coating amount at the mold head; It also includes: calculating the micrometer knob angle adjustment command based on the relationship between the surface density of small units and the knob angle of the die head micrometer; The coating machine parameter real-time adjustment module is configured to adjust the coating pump speed and / or the die head micrometer knob angle of the coating machine according to the adjustment command, so as to achieve the surface density control of the coating process.

6. The closed-loop control system for coating surface density as described in claim 5, characterized in that, The method of determining whether the coating surface density is qualified based on the density deviation includes: if the deviation of the coating surface density is greater than the upper limit value, then outputting a surface density too high command. If the density deviation of the coating surface density is less than the lower limit, output a low surface density command; If the density deviation of the coating surface density is greater than or equal to the lower limit and less than or equal to the lower limit, then the surface density is output as qualified.

7. A computer-readable storage medium having a program stored thereon, characterized in that, When executed by the processor, the program implements the steps in the closed-loop control method for coating surface density as described in any one of claims 1-4.

8. An electronic device, comprising a memory, a processor, and a program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps in the closed-loop control method for coating surface density as described in any one of claims 1-4.

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