Lithium battery spraying diaphragm coating consistency optimization system and method

Abstract

The invention discloses a lithium battery sprayed diaphragm coating consistency optimization system and method.According to the system and method, a plurality of spraying rotating discs connected to independent feeding branches are arranged, all the spraying rotating discs are sequentially arranged in the width direction of a diaphragm, and each spraying rotating disc conducts feeding independently and is driven by an independent motor; a first thickness gauge and a second thickness gauge are arranged before spraying and after spraying and drying of a diaphragm respectively, the first thickness gauge detects the thickness of a corresponding diaphragm area before spraying, the second thickness gauge detects the thickness of a corresponding diaphragm area after spraying and drying, and film surface thickness deviation value data before and after spraying are calculated and analyzed through a PLC control system. And in combination with a spraying coating thickness set value, under a PLC control system, the rotating speed of a spraying rotating disc feeding machine pump and a spraying rotating disc motor corresponding to each area is adjusted, the spraying film surface thickness data of each area is corrected to be within a set allowable deviation range, and the thickness of each area is consistent after the diaphragm is sprayed.

Description

Technical Field

[0001] The present invention relates to the field of lithium-ion battery diaphragm production, and in particular to a lithium battery spray diaphragm coating consistency optimization system and method. Background Art

[0002] As international issues such as energy crisis and environmental pollution become increasingly prominent, new energy vehicles and new energy power generation have become projects that countries around the world are actively developing and promoting. Lithium-ion batteries are currently relatively excellent power / energy storage batteries with comprehensive performance. As an important component, diaphragms have become one of the key materials restricting the development of lithium-ion battery technology. At present, the emergence of vehicles and energy storage batteries powered by lithium-ion batteries has put forward stringent requirements on the performance of lithium battery diaphragms. Therefore, the development of modified diaphragms and new diaphragms has become a research hotspot in recent years, and higher requirements have been put forward for diaphragms: ① higher heat resistance; ② uniform thickness; ③ higher electrochemical stability; ④ better liquid absorption performance; ⑤ lower cost. To a certain extent, the diaphragm determines the interface characteristics, internal resistance and ionic conductivity of the battery, affecting the capacity, cycle performance and safety performance of the battery.

[0003] The basic process flow of lithium-ion battery spray diaphragm production includes: unwinding - preheating - spray coating - drying - winding. In the field of membrane surface performance testing, testing parameters such as the uniformity of the coating thickness of the diaphragm are important links in judging whether the diaphragm meets the standards. At present, the rotary sprayer of the separator uses a set of motor feed pumps and flowmeter signal feedback control through PLC control to pump the feeder into the cylindrical slurry pipe, and ensures the relative consistency of feeding to multiple spray turntables through multiple discharge ports distributed at equal distances on the slurry pipe. Since the discharge ports are evenly spaced on the feed pipe and parameters such as the discharge port size are the same, the amount of slurry discharged from each discharge port is basically the same. However, due to the different settings of the feed port positions, the different horizontal levels of the slurry pipe, the different settings of the discharge port positions and other variable factors, there is a large deviation in the quality of the slurry discharged from each discharge port per unit time, and there is no means to correct this deviation, resulting in a large deviation in the amount of slurry entering each spray turntable. Since the amount of slurry flowing out of different discharge ports is different, through the rotation of the spray turntable, there is a large deviation in the amount of slurry thrown on the film per unit time. After the film is dried, sampling and monitoring show that the data deviation of the coating thickness on the spray film surface is large, which is ultimately reflected in the large deviations in the data such as the lateral grammage, needle puncture strength, and air permeability of the film surface, which ultimately leads to product degradation or even scrapping. Summary of the invention

[0004] The purpose of the present invention is to provide a system and method for optimizing the consistency of lithium battery spray diaphragm coating, so as to solve the technical problem of large thickness deviation of lithium battery diaphragm in the prior art.

[0005] The lithium battery spray diaphragm coating consistency optimization system of the present invention adopts the following technical scheme: a lithium battery spray diaphragm coating consistency optimization system, including a slurry barrel, the slurry barrel is connected to a slurry pipeline, which includes a spray assembly: the spray assembly is connected to the slurry pipeline, the spray assembly includes a spray turntable rotating under the drive of a motor and a feeder pump providing slurry to the spray turntable, there are more than two spray turntables, each spray turntable is arranged in sequence on the same side of the diaphragm membrane surface along the width direction of the diaphragm, and two adjacent spray turntables are staggered one high and one low, each spray turntable is driven by a separate motor, each spray turntable is configured with a separate spray window, and the spray window is located in front of the spray turntable; Detection assembly: comprising a first diaphragm thickness detection mechanism and a second diaphragm thickness detection mechanism, the first diaphragm thickness detection mechanism is used to detect the diaphragm thickness before slurry spraying, and the second diaphragm thickness detection mechanism is used to detect the diaphragm thickness after slurry spraying and drying; PLC control system: receives flow data from the outlet of the feeder pump and diaphragm thickness data measured by the first diaphragm thickness detection mechanism and the second diaphragm thickness detection mechanism, and is used to control the operating parameters of the feeder pump and the speed of the motor of the spray turntable.

[0006] At least two feed branches are connected in parallel to the slurry pipeline, and a feeder pump, a flow meter and a spray turntable are sequentially arranged on each feed branch along the slurry flow direction, and the flow meter is used to detect the slurry flow in the corresponding feed branch; the first diaphragm thickness detection mechanism includes a first thickness gauge, and the second diaphragm thickness detection mechanism includes a second thickness gauge, and the number of the first thickness gauge and the second thickness gauge is equal to the number of the spray turntable, and each first thickness gauge is arranged in sequence in the diaphragm width direction before spraying, and each second thickness gauge is arranged in sequence in the diaphragm width direction after spraying and drying. The PLC control system is connected with each feeder pump, flow meter, motor of the spray turntable, first thickness gauge and second thickness gauge through the circuit. The PLC control system is used to receive the flow data detected by each flow meter and the diaphragm thickness data detected by each first thickness gauge and second thickness gauge, and is also used to control the operating parameters of the feeder pump and the speed of the motor of the spray turntable.

[0007] The specifications and models of each spray turntable are the same, and the height difference between adjacent spray turntables is 5~10mm.

[0008] The speed range of the motor of the spray turntable is 3000~15000rpm, and the speed deviation range of the motor of the spray turntable is: -0.5%~+0.5%.

[0009] The flow rate range of the feeder pump is 1000~11000ml / min, and the measurement accuracy range of the flow meter is: -0.5%~+0.5%.

[0010] The PLC control system is connected to a display screen, which is used to display the flow rate of each feed branch pipe monitored by the PLC control system, the operating parameters of the feeder pump, the speed value of the spray turntable motor, and the thickness values ​​of each area detected by the first thickness gauge and the second thickness gauge.

[0011] The present invention discloses a method for optimizing the consistency of a lithium battery spray diaphragm coating, which adopts the following technical scheme: A method for optimizing the consistency of a lithium battery spray diaphragm coating, which comprises the following steps: (1) The slurry is fed from the slurry barrel to each spraying turntable of the spraying mechanism by a feeder pump, and the slurry flow rate entering each spraying turntable is set to the same value by adjusting the parameters of the feeder pump; (2) The spray turntables are arranged in sequence in the width direction of the diaphragm, and two adjacent spray turntables are arranged alternately, one high and one low. Each spray turntable is driven by a separate motor. The speed of the motor is adjusted to make the speed of each spray turntable the same. The spray turntable uses a high-speed rotating spraying method to apply the slurry to the diaphragm; (3) using a first diaphragm thickness detection mechanism to detect the diaphragm thickness before slurry spraying, and using a second diaphragm thickness detection mechanism to detect the diaphragm thickness after slurry spraying and drying, and sending the thickness values ​​detected by the first diaphragm thickness detection mechanism and the second diaphragm thickness detection mechanism to the PCL control system; (4) The PCL control system is used to calculate the difference between the thickness values ​​detected by the first diaphragm thickness detection mechanism and the second diaphragm thickness detection mechanism, and the calculated difference is compared with the set coating thickness. The speed of the motor of the spray turntable and the operating parameters of the feeder pump are adjusted through the PLC control system until the calculated difference is within the set coating thickness range.

[0012] Step (1) is specifically as follows: the slurry is fed into a slurry barrel for storage, and the slurry is fed into each spray turntable through the feeder pump on each feed branch pipe, and the flow rate of the slurry is detected by a flow meter before entering each spray turntable, and the flow rate of each feed branch pipe is set to the same value by adjusting each feeder pump; the diaphragm is divided into areas in the width direction equal to the number of spray turntables, and each area corresponds to the position of each spray turntable.

[0013] In step (3), the first diaphragm thickness detection mechanism includes a first thickness gauge, and the second diaphragm thickness detection mechanism includes a second thickness gauge. The number of the first thickness gauge and the second thickness gauge is equal to the number of the spraying turntable. The first thickness gauges are arranged in sequence in the width direction of the diaphragm before spraying, and the second thickness gauges are arranged in sequence in the width direction of the diaphragm after spraying and drying. Each first thickness gauge is used to detect the diaphragm thickness of the corresponding area before slurry spraying, and each second thickness gauge is used to detect the diaphragm thickness of the corresponding area after slurry spraying and drying. In step (5), the operating parameters of each feeder pump, the flow value measured by the flow meter, the speed of the motor, the thickness value detected by the second thickness gauge and the thickness value detected by the first thickness gauge are sent to the PCL control system, and the PLC control system is used to calculate the difference between the thickness values ​​detected by the second thickness gauge and the first thickness gauge in the same area. According to the difference in each area, the speed of the motor of the corresponding spraying turntable and the operating parameters of the feeder pump are adjusted until the difference in the area is within the set coating thickness range.

[0014] After the diaphragm is sprayed and dried, a length of the diaphragm is taken as a sample, and the diaphragm is divided into several diaphragm sample pieces corresponding to the area of ​​each spray turntable. The number of diaphragm sample pieces is equal to the number of spray turntables. Each diaphragm sample piece is weighed, and the diaphragm weight per unit area of ​​each diaphragm sample piece is calculated respectively. If the diaphragm weight per unit area of ​​a diaphragm sample piece is not within the set weight range, the speed of the motor of the spray turntable in the corresponding area of ​​the diaphragm sample piece and the operating parameters of the feeder pump are adjusted until the diaphragm weight per unit area of ​​the diaphragm sample piece in the area is within the set weight range.

[0015] When the coating weight of each area of ​​the diaphragm is kept within the allowable deviation range of the process, the measured values ​​of each flow meter, the operating data of the feeder pump, the speed of the spray turntable motor and other values ​​are entered into the PLC control system to obtain the correction parameters; in the spray production stage, the slurry is kept unchanged, and the diaphragm weight per unit area of ​​each diaphragm sample is measured at a certain interval according to the correction parameters obtained by the PLC control system, and the speed of the spray turntable motor and the operating parameters of the feeder pump are fine-tuned according to the set diaphragm weight per unit area.

[0016] The spray turntables are arranged in a direction perpendicular to the film surface running direction. Each spray turntable is equipped with a separate spray window. The specifications and models of the spray turntables are consistent. The spray turntables have the same effect in cutting the atomized slurry. The height difference between adjacent spray turntables is 5~10mm.

[0017] The beneficial effects of the present invention are as follows: the present invention utilizes a plurality of spraying turntables sequentially arranged along the width direction of the diaphragm to spray the slurry, the spraying turntable cuts the slurry into atomized form and throws it out when rotating at high speed, the adjacent spraying turntables are arranged in a staggered distribution mode of one high and one low, and each turntable is equipped with a separate spraying window, which greatly reduces the probability of collision between the slurry droplets thrown out of the adjacent turntables, thereby ensuring the uniformity of the spraying, improving the uniformity of the coating, and thus ensuring the stability of the gram weight data of the sprayed film surface; by respectively arranging a thickness detection mechanism before and after the spraying turntable, calculating the actual thickness of the coating, comparing the actual thickness of the coating with the set thickness, adjusting the rotation speed of the spraying turntable and the feed flow rate of the slurry according to the set thickness, thereby realizing the correction and adjustment of the film surface thickness after spraying, and improving the consistency of the spraying. The present invention can make the spraying of the lithium battery diaphragm coating product more uniform, the coating thickness more uniform, ensure the spraying quality of the product, and has high work efficiency and low production cost.

[0018] The present invention analyzes the data deviation values ​​of dry thickness data of different areas of the membrane surface before and after spraying, controls the feeder pump and the motor of the spray turntable corresponding to each path respectively, adjusts and controls the feed flow rate and the spraying speed respectively, and finally realizes the correction and adjustment of the membrane surface thickness data deviation before and after spraying, thereby ensuring the stable slurry supply and high-quality transportation of each spray turntable.

[0019] By comparing and analyzing the thickness gauge data before and after spraying and outputting PLC control signals, combined with the analysis of the weight data of the film surface coating detected manually, it is possible to optimize and adjust the coating weight in areas where the weight data of the film surface exceeds the process requirements, and finally achieve the purpose of optimizing and adjusting the consistency of the sprayed film weight. At the same time, due to the addition of the function of correcting and adjusting the weight of the sprayed coating in a certain area, the process production adjustment means are more flexible, avoiding the waste of resources caused by the lack of weight adjustment means for the film surface in some areas, resulting in a large output of waste film. In addition, through data comparison and analysis, real-time monitoring and adjustment of the consistency of the grammage data of the horizontal film surface can be achieved, which improves the effective control of the stability of the film surface performance. At the same time, it reduces the frequent operation of manual detection, reduces the labor intensity of personnel, and realizes the effective monitoring of the overall production quality of the coating film, saving a lot of production costs and improving the overall competitiveness of the enterprise. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic diagram of a lithium battery spray diaphragm coating consistency optimization system according to an embodiment of the present invention; Figure 2 It is a schematic diagram of the detection areas of the first thickness gauge and the second thickness gauge in a lithium battery spray diaphragm coating consistency optimization system according to an embodiment of the present invention; Figure 3 This is a process flow chart for producing lithium battery spray diaphragm coating using the present invention; Figure 4 It is a schematic diagram of the production process of a method for optimizing the consistency of a lithium battery spray diaphragm coating according to an embodiment of the present invention; Figure 5 is a table of Embodiment 1; Figure 6 This is a table for comparison example 1; Figure 7 This is a table for Example 2.

[0021] The numbers in the figure are: 1-spraying turntable, 2-slurry barrel, 3-feeder pump, 4-flow meter, 5-PLC control system, 6-display screen, 7-diaphragm, 8-first thickness gauge, 9-second thickness gauge. DETAILED DESCRIPTION

[0022] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] like Figure 1 to Figure 2 As shown, a lithium battery spray diaphragm coating consistency optimization system according to an embodiment of the present invention comprises a slurry barrel 2, a slurry pipe is connected to the slurry barrel 2, at least two feed branches are connected in parallel to the slurry pipe, and the number of feed branches in this embodiment is five, and each feed branch is provided with a feeder pump 3, a flow meter 4 and a spray turntable 1 in sequence along the slurry flow direction, and each spray turntable 1 is arranged in sequence in the width direction of the diaphragm 7, and the flow meter 4 is used to detect the slurry flow in the corresponding feed branch; a feeder pump 3, a flow meter 4 and a spray turntable 1 are provided before and after the spray turntable 1, respectively. A first diaphragm thickness detection mechanism and a second diaphragm thickness detection mechanism are provided. The first diaphragm thickness detection mechanism includes a first thickness gauge 8, and the second diaphragm thickness detection mechanism includes a second thickness gauge 9. The number of the first thickness gauges 8 and the second thickness gauges 9 are equal to the number of the spray turntable 1. The first thickness gauges 8 are arranged in sequence in the width direction of the diaphragm before spraying, and the second thickness gauges 9 are arranged in sequence in the width direction of the diaphragm after spraying and drying. The first thickness gauge 8 is used to detect the thickness of the diaphragm before slurry spraying, and the second thickness gauge 9 is used to detect the thickness of the diaphragm after slurry spraying and drying.

[0024] The lithium battery spray diaphragm coating consistency optimization device also includes a PLC control system 5, which is connected to each feeder pump 3, flow meter 4, the motor of the spray turntable 1, the first thickness gauge 8 and the second thickness gauge 9 through a circuit. The PLC control system 5 is used to receive the flow data detected by each flow meter 4 and the diaphragm thickness data detected by each first thickness gauge 8 and the second thickness gauge 9, and is also used to control the operating parameters of the feeder pump 3 and the speed of the motor of the spray turntable 1. The PLC control system 5 is connected to a display screen 6, which is used to display various data monitored by the PLC control system 5, including the flow of each feed branch pipe, the operating parameters of the feeder pump, the speed value of the spray turntable motor, and the thickness values ​​of each area detected by the first thickness gauge and the second thickness gauge.

[0025] In this embodiment, there are five spraying turntables 1, and each spraying turntable 1 is evenly arranged in the width direction of the diaphragm 7. The specifications and models of each spraying turntable 1 are the same. Adjacent spraying turntables 1 are arranged in a staggered distribution of one high and one low, and the height difference between adjacent spraying turntables is 5-10mm. When the spraying turntable rotates at high speed, the slurry is cut, atomized and thrown out. Adjacent spraying turntables are arranged in a staggered distribution of one high and one low. Each turntable is equipped with a separate spraying window, which greatly reduces the probability of slurry droplet collision and ensures the stability of the gram weight data of the sprayed film surface.

[0026] The speed range of the motor of the spray turntable is 3000~15000rpm, and the speed deviation range of the motor of the spray turntable is: -0.5%~+0.5%. By adjusting the speed of the motor of the spray turntable, the size of the spray droplets can be effectively adjusted to reduce the occurrence of the spray droplet problem.

[0027] The feeder pump 3 can adjust the driving speed according to the detection value of the flow meter 4, and realize the pump pressure delivery and supply of the slurry. The flow range of the feeder pump is 1000~11000ml / min, which can realize stable feeding. The measurement accuracy range of the flow meter is: -0.5%~+0.5%, which can realize controllable flow fluctuation and high-precision stable feeding.

[0028] The usage process of the lithium battery spray diaphragm coating consistency optimization system of this embodiment is as follows: first, the slurry is sent to the slurry barrel for storage, and the slurry enters each feed branch pipe through the slurry pipe, and is sent to each spray turntable after the flow detection of each feed branch pipe, and the flow meter on each feed branch pipe is adjusted to display the same flow value by adjusting the feeder pump; the slurry is introduced into the spray turntable through the feed branch pipe, and each spray turntable is driven by a separate motor. The motor is adjusted to set each spray turntable to the same speed, and the spray turntable adopts a high-speed rotary spraying method to coat the slurry onto the diaphragm.

[0029] The first thickness gauge is located in front of the spray turntable. Each first thickness gauge is used to detect the thickness of each area of ​​the diaphragm before spraying. The second thickness gauge is located after the spray turntable and the drying equipment. Each second thickness gauge is used to detect the thickness of each area of ​​the diaphragm after spraying and drying. The slurry supply flow of each feed pipeline is kept stable and each turntable equipment is in good working condition. The thickness data detected by each first thickness gauge and the second thickness gauge are respectively sent to the PLC control system, such as Figure 2 As shown in the figure, the diaphragm areas detected by the five first thickness gauges are divided into A1, A2, A3, A4, and A5, and the areas detected by the five second thickness gauges are divided into B1, B2, B3, B4, and B5. A1, A2, A3, A4, and A5 correspond to the positions of B1, B2, B3, B4, and B5 areas respectively. After the PLC control system calculates and analyzes the film surface thickness deviation data (B1-A1, B2-A2, B3-A3, B4-A4, and B5-A5) of each corresponding area, combined with the process setting value of the spray coating thickness data, the PLC control system adjusts the output signals of the motor and feeder pump of the spray turntable corresponding to each area, adjusts the speed of the motor of the spray turntable and the operating parameters of the feeder pump, and corrects the spray film surface thickness data of each area to within the deviation range allowed by the process setting.

[0030] According to the correspondence between the dry thickness and dry weight of the sprayed film surface per unit area, the deviation of the dry thickness and weight data of the sprayed film surface can be corrected. At the same time, the weight data of the sprayed film surface coating is detected and recorded by manual detection. The PLC adjustment data is corrected and compared through manual detection data, and the data is fine-tuned, so that the weight value of the coating in each area of ​​the film surface is finally kept within the allowable deviation range of the process. Finally, the measured values ​​of each flow meter in each spraying area, the operating data of the feeder pump, and the speed of the spray turntable motor are entered into the PLC control system to obtain the correction parameters.

[0031] During the spraying production stage, the slurry formula parameters used in production (slurry formula, viscosity, solid content, etc.) are kept consistent with the parameters in the testing stage. Based on the correction parameters obtained by the PLC control system and multiple weight tests on the membrane surface, adjustment and optimization of the coating weight data as well as rapid response are achieved during the spraying production process.

[0032] like Figure 3 As shown, the process flow of the lithium battery spray membrane coating production using the present invention includes: unwinding - preheating - measuring the membrane thickness - spray coating - drying - measuring the membrane thickness - winding.

[0033] like Figure 4 As shown, a method for optimizing the consistency of a lithium battery spray diaphragm coating according to an embodiment of the present invention comprises the following steps: (1) The slurry is sent to the slurry barrel for storage, and the slurry is sent to the corresponding spray turntable through the feeder pump on each feed branch pipe. The flow rate of the slurry is detected by the flow meter before entering the spray turntable, and the flow rate of each feed branch pipe is set to the same value by adjusting the feeder pump.

[0034] (2) Each spray turntable is arranged in sequence in the width direction of the diaphragm, and each spray turntable is driven by a separate motor. The speed of each spray turntable is adjusted to make the speed of each spray turntable the same. The spray turntable adopts a high-speed rotary spraying method to apply the slurry to the diaphragm; the diaphragm is divided into areas equal to the number of spray turntables in the width direction, and each area corresponds to the position of each spray turntable; in this step, the specifications and models of each spray turntable are consistent, and the effect of cutting the atomized slurry by each turntable is the same. The spray turntable is arranged in a direction perpendicular to the film surface running direction, and the vertical distance from the spray head of each spray turntable to the film surface is equal. In this embodiment, adjacent spray turntables are arranged in a staggered distribution of one high and one low, and each spray turntable is equipped with a separate spray window. The height difference between adjacent spray turntables is 5~10mm.

[0035] In other embodiments of the present invention, the spraying turntables may be arranged at the same height, and the vertical distance from the spraying head of each spraying turntable to the film surface is equal.

[0036] (3) A first thickness gauge is respectively arranged on the diaphragm at a position corresponding to each spray turntable before the spray turntable, and the first thickness gauges are arranged in sequence along the width direction of the diaphragm, and each first thickness gauge is used to detect the thickness of the diaphragm in the corresponding area before the diaphragm is sprayed; a second thickness gauge is respectively arranged on the diaphragm at a position corresponding to each spray turntable after the spray turntable and after the drying device, and the second thickness gauges are arranged in sequence along the width direction of the diaphragm, and the second thickness gauges are used to detect the thickness of the diaphragm in the corresponding area after the diaphragm is sprayed and dried.

[0037] (4) The operating parameters of each feeder pump, the flow value measured by the flow meter, the speed of the motor, the thickness value detected by the second thickness gauge and the thickness value detected by the first thickness gauge are sent to the PCL control system.

[0038] (5) After keeping the slurry flow rate in each feed branch stable, use the PLC control system to calculate the difference in thickness between the second thickness gauge and the first thickness gauge in the same area. The difference is the detected thickness difference. If the detected thickness difference in a certain area is not within the set coating thickness range, the PLC control system is used to adjust the motor speed of the spray turntable and the operating parameters of the feeder pump corresponding to the area until the detected thickness difference in the area is within the set coating thickness range.

[0039] (6) After the diaphragm is sprayed and dried, a length of the diaphragm is taken as a sample. The diaphragm is divided into a number of diaphragm sample pieces corresponding to each area of ​​the spray turntable. The number of diaphragm sample pieces is equal to the number of spray turntables. Each diaphragm sample piece is weighed and the diaphragm weight per unit area of ​​each diaphragm sample piece is calculated. If the diaphragm weight per unit area of ​​a diaphragm sample piece is not within the set weight range, the speed of the motor of the spray turntable in the area corresponding to the diaphragm sample piece and the operating parameters of the feeder pump are adjusted until the diaphragm weight per unit area of ​​the diaphragm sample piece in the area is within the set weight range.

[0040] (7) When the coating weight of each area of ​​the diaphragm is kept within the allowable deviation range of the process, the measured values ​​of each flow meter, the operating data of the feeder pump, the speed of the spray turntable motor and other values ​​are entered into the PLC control system to obtain the correction parameters; in the spray production stage, the slurry is kept unchanged, and the diaphragm weight per unit area of ​​each diaphragm sample is measured at a certain interval according to the correction parameters obtained by the PLC control system, and the speed of the spray turntable motor and the operating parameters of the feeder pump are fine-tuned according to the set diaphragm weight per unit area.

[0041] The PLC control system 5 can monitor the flow data of each feed branch pipe and the motor speed data of the spray turntable, record and analyze them, and output signals to each feeder pump and the motor of the spray turntable to control the flow and the speed of the spray turntable respectively. The flow value of the feeder pump and the motor speed value of the spray turntable can be set and written through the PLC control system 5, so as to control the speed of each feeder pump and the motor of the spray turntable. The first thickness gauge 8 can detect the membrane surface thickness data of each transverse area of ​​the membrane surface of the diaphragm before spraying, and transmit this thickness data signal to the PLC control system 5; the second thickness gauge 9 can detect the membrane surface thickness data of each transverse area of ​​the membrane surface of the diaphragm after spraying and drying, and transmit this thickness signal to the PLC control system 5; the display screen 6 is used to display the monitored data, which includes the flow of each feed branch pipe, the operating parameters of the feeder pump, the motor speed value of the spray turntable, and the thickness values ​​of each area detected by the first thickness gauge and the second thickness gauge.

[0042] During the test phase, the slurry supply flow rate of each feeding pipeline is kept stable, and each spray turntable 1 is in good working condition. Each first thickness gauge 8 and each second thickness gauge 9 sends the thickness data of each detected area to the PLC control system 5 respectively. The area detected by the first thickness gauge 8 is divided into A1, A2, A3, A4, and A5, and the area detected by the second thickness gauge 9 is divided into B1, B2, B3, B4, and B5. The area positions of A1, A2, A3, A4, and A5 correspond to those of B2, B3, B4, and B5 respectively. After the PLC control system 5 calculates and analyzes the film thickness deviation data of each corresponding area (B1-A1, B2-A2, B3-A3, B4-A4, B5-A5), combined with the process setting value of the spray coating thickness data, the PLC control system 5 respectively outputs the motor signals of the spray turntable feeder pump 3 and the spray turntable 4 corresponding to each area, and corrects the spray film thickness data of each area to within the deviation range allowed by the process setting. According to the corresponding relationship between the dry thickness and dry weight data of the spray film surface per unit area, the deviation of the dry thickness gram weight data of the spray film surface can be corrected. At the same time, the gram weight data of the spray film surface coating is detected and recorded by manual detection. The PLC adjustment data is corrected and compared through manual detection data, and the data is fine-tuned, and finally the gram weight values ​​of the coating in each area of ​​the film surface are kept within the process allowable deviation range. Finally, the values ​​of the flow meters, feeder pumps, and turntable motor speeds of each spraying area are entered into the PLC control system.

[0043] By keeping the slurry formula parameters (slurry formula, viscosity, solid content and other parameters) used in production consistent with the parameters in the test stage during the spraying production stage, and controlling the parameter correction through the PLC system 5, combined with manual inspection methods such as the first inspection and the last inspection of the membrane surface, the adjustment and optimization of the coating weight data and rapid response can be achieved during the spraying production process.

[0044] The present invention is further described below through several specific embodiments.

[0045] Operation of the spray coating machine: the production speed of the coating machine is 100m / min, the spraying turntable is set to a speed of 6000rpm, each group of spraying turntables uses a separate feed branch pipe for feeding, and each spraying turntable can be supplied with slurry separately through its own flow meter 4 and feeder pump 3, and the feed branch pipe flow rate is adjustable. The following embodiments and comparative examples all select a wet synchronous double-drawn polyethylene diaphragm with a thickness of 7μm as the substrate diaphragm, and plan to produce 7+1 spray coating film products, that is, a 7μm substrate diaphragm is selected, and the dry thickness of the spray coating is 1μm. After the relationship between the film surface coating thickness and the coating gram weight data is converted and calculated, the coating dry thickness of 1μm corresponds to the diaphragm coating gram weight data of about 0.65g / ㎡, and the process allows the gram weight data deviation range to be ±0.2g / ㎡. The solid content range of the selected spray coating slurry is 8% to 15%, and the length of the spray film roll is 1200 meters / roll.

[0046] Embodiment 1: In this embodiment, there are 5 spray turntables, which are arranged in a staggered manner, one high and one low. The turntable nozzle at the high position is 48mm away from the membrane surface, and the turntable nozzle at the low position is 42mm away from the membrane surface. The height difference between adjacent spray turntables is 8mm. The first thickness gauge 8 and the second thickness gauge 9 can respectively detect the dry thickness data of the membrane surface of each area (area A1 to A5, area B1 to B5) before and after spraying, and feed it back to the PLC control system 5. Each feeder pump 3 and flow meter 4 can respectively transport and measure the slurry of each feed branch pipe. The PLC control system 5 measures the dry thickness data of the membrane surface before and after spraying. According to the data analysis of the deviation value, the actual gram weight data of the spray coating in the area is calculated, and the signal is output to each individual feeder pump 3, flowmeter 4 and spray turntable 5 motor to control and adjust the spray flow in the area, and finally realize the correction and adjustment of the film thickness data deviation before and after spraying. For example, if the coating gram weight data in a certain area is lower than the process control requirement range, the PLC can achieve the purpose of improving the coating gram weight data by increasing the feed flow of the spray head in the area through real-time data analysis. Through real-time data analysis and real-time adjustment of the feed flow, it can always be within the process control requirement range; vice versa. The coating gram weight data of each area of ​​the membrane surface is obtained through manual detection. In order to facilitate data recording and effect tracking observation, the data is recorded once every 400 meters of the membrane surface length, and a total of four times.

[0047] In order to better illustrate the technical effects achieved by the present invention, the present invention uses several comparative examples to illustrate the significant progress achieved by the present invention.

[0048] Comparative Example 1: In this embodiment, there are 5 spray turntables, the nozzle of each spray turntable is equal to the diaphragm spacing, the vertical distance between the nozzle and the membrane surface is 50 mm, and the adjacent spray turntables are arranged at the same horizontal height, and there is no high and low staggered distribution. Each feeder pump 3 and flow meter 4 can respectively transport and measure the slurry flow of each feed branch pipe, and the flow setting value of each feed branch pipe is set to 300ml / min through the PLC control system 5 to control the flow. During the spraying production process, manual sampling and detection are performed at the first inspection position of the membrane surface (0-meter position of the membrane surface length) to obtain the dry thickness data of each area (area B1 to B5) of the membrane surface after spraying and drying treatment. The membrane surface thickness, gram weight and other parameters are manually detected at the positions of 400 meters, 800 meters, and 1200 meters of the membrane surface length, but no process parameter adjustment is made. In order to facilitate data recording and effect tracking observation, data is recorded once every 400 meters of membrane surface length, and a total of four times.

[0049] Comparative Example 2: In this embodiment, there are 5 spray turntables, which are arranged in a staggered manner with one high and one low. The adjacent spray turntables are arranged in a staggered manner with one high and one low. The height difference between adjacent spray turntables is 8mm, which can effectively reduce the collision probability of droplets thrown out of adjacent spray turntables, and the morphology of the spray points on the membrane surface is more regular. The corresponding feeder pump 3 is driven by the feedback flow of the flow meter 4 to supply slurry to each spray turntable. The slurry flow of each spray turntable can maintain a relatively stable consistency. The flow rate of the feed branch pipe is set to 1500ml / min. During the spraying production process, manual sampling and detection are performed at the first inspection position of the membrane surface (0-meter position of the membrane surface length) to obtain the dry thickness data of each area (area B1 to B5) of the membrane surface after spraying and drying. The membrane surface thickness, gram weight and other parameters are manually detected at the positions of 400 meters, 800 meters, and 1200 meters in length, respectively, without any process parameter adjustment. To facilitate data recording and effect tracking and observation, data was recorded once every 400 meters of membrane surface length, for a total of four times.

[0050] Combined with the manual detection data of the membrane surface performance by the detection personnel and the display screen data of the monitoring mechanism, the flow counting value, coating weight and other data detected by the above embodiment of the present invention and the comparative example are compared, and the data are as follows: Figures 5 to 7 As shown in the table, Figures 5 to 7 The table shows data only for three regions of the diaphragm.

[0051] from Figure 5 It can be seen from the data in that Example 1 detects and analyzes the deviation value of the dry thickness data of the film surface before and after spraying, and controls the feeder pump and flow meter of each channel in real time, and finally realizes the rapid correction and adjustment of the deviation of the film surface thickness data before and after spraying. By setting different coating weight values, coating films with different coating weights can be sprayed and produced, and adjacent spray turntables are arranged in a high and low staggered distribution layout, which can effectively reduce the probability of mutual collision of droplets thrown out by adjacent spray turntables, and reduce the loss of slurry droplets drifting. In the spraying production, the coating weight data fluctuation can be monitored and kept small, and the coating weight fluctuation is ±0.01g / ㎡.

[0052] from Figure 6It can be seen from the data in that in comparative example 1, by setting the set value of the slurry flow rate of each feed pipeline, and through manual sampling and detection of the first inspection of the membrane surface and correcting the parameter settings, it can be monitored in the spraying production that the coating weight data has large fluctuations, the coating weight fluctuation is ±0.03g / ㎡, the adjacent spray turntables are arranged at the same horizontal height, and there is no high and low staggered distribution layout. There is a problem of mutual collision between droplets thrown out by adjacent spray turntables, and the loss of slurry droplet drifting increases. In comparison, the coating weight data is reduced by about 0.02g / ㎡, and the coating weight data deviation range is ±0.03g / ㎡. Although it does not exceed the numerical range of the coating weight deviation allowed by the process (±0.2g / ㎡), there is no effective means to promptly discover the over-limit problem and promptly correct the coating weight parameters. A large number of problematic membranes whose membrane surface weight data do not meet the process requirements may be generated, and there are major process production risks.

[0053] from Figure 7 It can be seen from the data in that in Example 2, the coating weight data of each area of ​​the film surface was obtained through manual detection. After data comparison, it was found that the weight data of a certain area of ​​the film surface had a large deviation from the data of other areas (coating weight fluctuation ±0.12g / ㎡), and no effective means or measures could be provided to adjust the coating weight data of certain areas of the film surface. A large number of problematic films with film weight data that did not meet the process requirements were generated, resulting in film performance parameters that were not within the controllable range, and even malicious incidents of scrapping the entire roll of coated film.

[0054] To sum up, under the premise that the spray turntable is in a stable working state, through data analysis of the deviation value of the dry thickness data of the film surface before and after spraying, and closed-loop control of each feeder pump and flow meter, the deviation of the film surface thickness data before and after spraying can be corrected and adjusted, and the deviation of the gram weight data of the film surface coating can be within a relatively small range (≤0.01g / ㎡), so as to achieve the purpose of consistency of coating thickness and gram weight data.

[0055] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the protection scope of the present invention in any form, and all technical solutions obtained by equivalent replacement and the like fall within the protection scope of the present invention.

[0056] The parts not involved in the present invention are the same as the prior art or can be implemented by using the prior art.

Claims

1. A lithium battery spray diaphragm coating consistency optimization system, comprising a slurry barrel, a slurry pipeline connected to the slurry barrel, characterized in that: These include, Spraying assembly: The spraying assembly is connected to the slurry pipeline, and the spraying assembly includes a spraying turntable rotating under the drive of a motor and a feeder pump for supplying slurry to the spraying turntable. There are more than two spraying turntables, and each spraying turntable is sequentially arranged on the same side of the membrane surface of the diaphragm along the width direction of the diaphragm. Two adjacent spraying turntables are staggered, one high and one low. Each spraying turntable is driven by a separate motor, and each spraying turntable is equipped with a separate spraying window, which is located in front of the spraying turntable; Detection assembly: comprising a first diaphragm thickness detection mechanism and a second diaphragm thickness detection mechanism, the first diaphragm thickness detection mechanism is used to detect the diaphragm thickness before slurry spraying, and the second diaphragm thickness detection mechanism is used to detect the diaphragm thickness after slurry spraying and drying; PLC control system: receives flow data from the outlet of the feeder pump and diaphragm thickness data measured by the first diaphragm thickness detection mechanism and the second diaphragm thickness detection mechanism, and is used to control the operating parameters of the feeder pump and the speed of the motor of the spray turntable.

2. The lithium battery spraying diaphragm coating consistency optimization system according to claim 1, characterized in that: At least two feed branches are connected in parallel to the slurry pipeline, and a feeder pump, a flow meter and a spray turntable are sequentially arranged on each feed branch along the slurry flow direction, and the flow meter is used to detect the slurry flow in the corresponding feed branch; The first diaphragm thickness detection mechanism includes a first thickness gauge, and the second diaphragm thickness detection mechanism includes a second thickness gauge. The number of the first thickness gauges and the second thickness gauges is equal to the number of the spraying turntables. The first thickness gauges are arranged in sequence in the width direction of the diaphragm before spraying, and the second thickness gauges are arranged in sequence in the width direction of the diaphragm after spraying and drying. Each first thickness gauge is used to detect the thickness of the diaphragm in the corresponding area before slurry spraying, and each second thickness gauge is used to detect the thickness of the diaphragm in the corresponding area after slurry spraying and drying. The PLC control system is connected to each feeder pump, flow meter, motor of the spray turntable, first thickness gauge and second thickness gauge through circuits. The PLC control system is used to receive flow data detected by each flow meter and diaphragm thickness data detected by each first thickness gauge and second thickness gauge, and is also used to control the operating parameters of the feeder pump and the speed of the motor of the spray turntable.

3. The lithium battery spraying diaphragm coating consistency optimization system according to claim 1, characterized in that: The specifications and models of each spray turntable are the same, and the height difference between adjacent spray turntables is 5~10mm.

4. The lithium battery spraying diaphragm coating consistency optimization system according to claim 1, characterized in that: The speed range of the motor of the spray turntable is 3000~15000rpm, and the speed deviation range of the motor of the spray turntable is: -0.5%~+0.5%.

5. The lithium battery spraying diaphragm coating consistency optimization system according to claim 1, characterized in that: The PLC control system is connected to a display screen, which is used to display the flow rate of each feed branch pipe monitored by the PLC control system, the operating parameters of the feeder pump, the speed value of the spray turntable motor, and the thickness values ​​of each area detected by the first thickness gauge and the second thickness gauge.

6. A method for optimizing the consistency of lithium battery spray diaphragm coating, characterized in that: It includes the following steps: (1) The slurry is fed from the slurry barrel to each spraying turntable of the spraying mechanism by a feeder pump, and the slurry flow rate entering each spraying turntable is set to the same value by adjusting the parameters of the feeder pump; (2) The spray turntables are arranged in sequence in the width direction of the diaphragm, and two adjacent spray turntables are arranged alternately, one high and one low. Each spray turntable is driven by a separate motor. The speed of the motor is adjusted to make the speed of each spray turntable the same. The spray turntable uses a high-speed rotating spraying method to apply the slurry to the diaphragm; (3) using a first diaphragm thickness detection mechanism to detect the diaphragm thickness before slurry spraying, and using a second diaphragm thickness detection mechanism to detect the diaphragm thickness after slurry spraying and drying, and sending the thickness values ​​detected by the first diaphragm thickness detection mechanism and the second diaphragm thickness detection mechanism to the PCL control system; (4) The PCL control system is used to calculate the difference between the thickness values ​​detected by the first diaphragm thickness detection mechanism and the second diaphragm thickness detection mechanism, and the calculated difference is compared with the set coating thickness. The speed of the motor of the spray turntable and the operating parameters of the feeder pump are adjusted through the PLC control system until the calculated difference is within the set coating thickness range.

7. The method for optimizing the consistency of the lithium battery spray diaphragm coating according to claim 6, characterized in that: Step (1) is specifically as follows: the slurry is fed into a slurry barrel for storage, and the slurry is fed into each spray turntable through the feeder pump on each feed branch pipe, and the flow rate of the slurry is detected by a flow meter before entering each spray turntable, and the flow rate of each feed branch pipe is set to the same value by adjusting each feeder pump; the diaphragm is divided into areas in the width direction equal to the number of spray turntables, and each area corresponds to the position of each spray turntable.

8. The method for optimizing the consistency of the lithium battery spray diaphragm coating according to claim 6, characterized in that: In step (3), the first diaphragm thickness detection mechanism includes a first thickness gauge, and the second diaphragm thickness detection mechanism includes a second thickness gauge. The number of the first thickness gauge and the second thickness gauge is equal to the number of the spraying turntable. The first thickness gauges are arranged in sequence in the width direction of the diaphragm before spraying, and the second thickness gauges are arranged in sequence in the width direction of the diaphragm after spraying and drying. Each first thickness gauge is used to detect the diaphragm thickness of the corresponding area before slurry spraying, and each second thickness gauge is used to detect the diaphragm thickness of the corresponding area after slurry spraying and drying. In step (5), the operating parameters of each feeder pump, the flow value measured by the flow meter, the speed of the motor, the thickness value detected by the second thickness gauge and the thickness value detected by the first thickness gauge are sent to the PCL control system, and the PLC control system is used to calculate the difference between the thickness values ​​detected by the second thickness gauge and the first thickness gauge in the same area. According to the difference in each area, the speed of the motor of the corresponding spraying turntable and the operating parameters of the feeder pump are adjusted until the difference in the area is within the set coating thickness range.

9. The method for optimizing the consistency of the lithium battery spray diaphragm coating according to claim 6, characterized in that: After the diaphragm is sprayed and dried, a length of the diaphragm is taken as a sample, and the diaphragm is divided into several diaphragm sample pieces corresponding to the area of ​​each spray turntable. The number of diaphragm sample pieces is equal to the number of spray turntables. Each diaphragm sample piece is weighed, and the diaphragm weight per unit area of ​​each diaphragm sample piece is calculated respectively. If the diaphragm weight per unit area of ​​a diaphragm sample piece is not within the set weight range, the speed of the motor of the spray turntable in the corresponding area of ​​the diaphragm sample piece and the operating parameters of the feeder pump are adjusted until the diaphragm weight per unit area of ​​the diaphragm sample piece in the area is within the set weight range.

10. The method for optimizing the consistency of the lithium battery spray diaphragm coating according to claim 6, characterized in that: When the coating weight of each area of ​​the diaphragm is kept within the process tolerance range, the measured values ​​of each flow meter, the operating data of the feeder pump and the speed of the spray turntable motor are entered into the PLC control system to obtain the correction parameters; During the spraying production stage, the slurry is kept unchanged. According to the correction parameters obtained by the PLC control system, the diaphragm weight per unit area of ​​each diaphragm sample is measured at a certain interval. The speed of the motor of the spray turntable and the operating parameters of the feeder pump are fine-tuned according to the set diaphragm weight per unit area.

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