Battery electrode coil material coating method, device and system

Abstract

The invention belongs to the technical field of ray detection, and particularly relates to a battery electrode roll material coating device and a method for implementing detection by using the same, through cross real-time control of parameters such as discharging speed, pressing thickness, drying temperature and rolling speed, secondary coating and compaction compensation can be performed on a currently detected unqualified coating quality section, and the detection accuracy is improved. And the system parameters can be timely adjusted, the coating quality of the subsequent coil stock is improved, the accurate and uniform coating of the pole piece is realized, the related deviation is compensated in real time under the non-stop condition, and the production efficiency is improved. Based on the same inventive concept, the invention further provides a medium and a system storing the method program, and the medium and the system are used for executing the battery electrode coil material coating method.

Description

Technical Field

[0001] The present invention belongs to the technical field of new energy batteries, and discloses a battery electrode coil coating method, device, system, and recording medium storing a program capable of executing the method. Background Art

[0002] The coating process is a key process for covering the surface of a substrate with lithium battery slurry through an extrusion die head. The coating uniformity and coating accuracy will directly affect the quality of the electrode sheet. At the same time, the coating process is a high-energy-consuming link in the production of lithium batteries. The energy consumption of a single unit is as high as 200 kW·h, and most of the energy consumption is generated during the drying process. Therefore, the coating quality control and energy consumption optimization of coating machines have gradually attracted the attention of this industry.

[0003] The prior art involves closed-loop control of the coating areal density when dealing with coating accuracy, and generally compensates by adjusting the coating pump speed. However, this compensation only works for subsequent coils. Either the coils with unqualified areal density in the front are accepted with concessions or become waste products. And a certain patent discloses a double-sided coating device for lithium-ion battery electrode sheets, which adjusts the tension of the electrode sheet up and down by adjusting the height of the tension idler roller. Due to the limited movement of the tension idler roller, this method has insufficient ability to limit the freedom of the substrate when the tension fluctuates, and it is still difficult to ensure the coating quality.

[0004] In addition, if the overall average pump speed is reasonable, how to solve the local non-uniformity caused by blockage or obstruction in only some individual areas is also an urgent problem to be solved in this field. Summary of the Invention

[0005] To solve the problems raised in the background art, the present invention provides a battery electrode coil coating device, including: a substrate unwinding unit, a transmission line, an oven, and a winding mechanism connected in sequence, wherein the transmission line includes a first coating module strip, a first areal density detection strip, a first pressing roller, a second coating module strip, a second areal density detection strip, and a second pressing roller arranged in parallel between the substrate unwinding unit and the oven along the transmission direction; and a controller electrically connected to the temperature sensor and the temperature control module in the oven, and the controller is also electrically connected to the first coating module strip, the first areal density detection strip, the first pressing roller, the second coating module strip, the second areal density detection strip, and the second pressing roller respectively.

[0006] Preferably, the controller is also electrically connected to the winding mechanism for controlling the winding speed.

[0007] Preferably, both the first coating module strip and the second coating module strip are configured as single-row spraying modules, and the distance between adjacent nozzles is 20 mm - 50 mm.

[0008] Based on the same inventive concept, the present application also provides a method for coating a battery electrode coil stock, using the above-mentioned battery electrode coil stock coating device, including the following steps:

[0009] S1. Set the coating areal density according to the coating material, distribute the coating amounts of the first coating module strip and the second coating module strip, and set the initial slurry flow rates of each nozzle and the initial displacement amount of the pressing roller;

[0010] S2. Unwind the base material to unfold the base material, perform a first coating through the first coating module strip, then detect the areal density through the first areal density detection strip, and adjust the downward pressing distance of the first pressing roller for compensation according to the deviation between the average areal density at this place and the set areal density. If the downward pressing distance of the first pressing roller is adjusted to the limit and is still insufficient for compensation, then adjust the flow rates of the nozzles on the first coating module strip;

[0011] S3. Adjust the flow rates of the nozzles at the corresponding positions of the second coating module strip for compensation according to the fluctuation condition of the areal density at different positions in the cross-cutting direction of the conveyor belt; if the flow rates of the nozzles at the corresponding positions of the second coating module strip are adjusted to the limit and are still insufficient for compensation, then increase the drying temperature and at the same time adjust the flow rates of the nozzles at the corresponding positions on the first coating module strip;

[0012] S4. The electrode coil stock after the first coating is pressed by the first pressing roller and then undergoes a second coating through the second coating module strip, and then undergoes areal density detection through the second areal density detection strip, and adjust the downward pressing distance of the second pressing roller for compensation according to the deviation between the average areal density at this place and the set areal density;

[0013] S5. The electrode coil stock after being pressed by the second pressing roller enters the oven for heating and drying, and after drying, it is wound by the winding mechanism into a finished electrode coil.

[0014] Preferably, if the deviation between the average areal density after the first coating and the set areal density exceeds a preset threshold value, the controller adjusts the winding speed of the winding mechanism to change the relaxation process of the slurry.

[0015] Another aspect of the present invention lies in providing a non-transitory readable recording medium for storing one or more programs including a plurality of instructions, which, when the instructions are executed, will cause the processor to execute the above-mentioned method for coating a battery electrode coil stock.

[0016] The present invention also provides a battery electrode coil stock coating system, including a processing circuit and a memory electrically coupled thereto, characterized in that the memory is configured to store at least one program, the program includes a plurality of instructions, and the processing circuit runs the program to be able to execute the above-mentioned method for coating a battery electrode coil stock.

[0017] Compared with the prior art, the battery electrode coil coating method in the present invention can, through the cross real-time control of parameters such as the discharging speed, pressing thickness, drying temperature, and winding speed, not only perform secondary coating and compaction compensation on the detected unqualified coating quality section, but also timely adjust the system parameters to improve the coating quality of subsequent coils, achieve precise and uniform coating of the electrode sheet, compensate for relevant deviations in real time without stopping the machine, and improve production efficiency. Brief Description of the Drawings

[0018] Figure 1 It is a structural diagram of the battery electrode coil coating device in the embodiment of the present invention;

[0019] In the figure, 1 - oven; 2 - second pressing roller; 3 - second surface density detection strip; 4 - first pressing roller; 5 - second coating module strip; 6 - first surface density detection strip; 7 - first coating module strip; 8 - temperature control module. Specific Embodiments

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be described below with reference to the accompanying drawings in the embodiments of the present invention. The described embodiments are some but not all of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts fall within the protection scope of the present invention.

[0021] The following combines the technical solutions and the attached Figure 1 drawings to specifically illustrate the implementation process of the present invention, including a battery electrode coil coating device and a method for coating a battery electrode coil using the device.

[0022] In the production of lithium batteries, the production quality of the positive electrode sheet is affected by three important parameters: surface density, compaction density, and thickness consistency. These parameters directly affect the internal resistance of the battery, thereby affecting the performance of the battery. By reducing the surface density, appropriately increasing the compaction density, and improving the thickness consistency, the internal resistance of the battery can be reduced, thereby improving the performance of the lithium battery. The basic principle is to reduce the impedance between the electrode sheet and the electrolyte by adjusting the above parameters to improve the battery performance.

[0023] To this end, the designed battery electrode web coating device includes a substrate unwinding unit, a transmission line, an oven 1, and a winding mechanism connected in sequence. The transmission line includes a first coating module strip 7, a first areal density detection strip 6, a first pressing roller 4, a second coating module strip 5, a second areal density detection strip 3, and a second pressing roller 2, which are arranged in parallel between the substrate unwinding unit and the oven along the transmission direction. It further includes a controller electrically connected to the temperature sensor and the temperature control module 8 in the oven. The controller is also electrically connected to the first coating module strip 7, the first areal density detection strip 6, the first pressing roller 4, the second coating module strip 5, the second areal density detection strip 3, and the second pressing roller 2 respectively. Among them, the controller is also electrically connected to the winding mechanism for controlling the winding speed. Both the first coating module strip 7 and the second coating module strip 5 are configured with single-row spraying modules, and the distance between adjacent nozzles is 30 mm.

[0024] First, due to different types of cathode materials, there will be differences in their coating areal density. If different types of electrode materials need to be coated, the coater needs to be thoroughly cleaned. Differences in coating areal density:

[0025] Cathode, material - ternary material (NCM) - areal density 20 - 30 mg / cm2

[0026] Cathode, material - lithium iron phosphate (LFP) - areal density 25 - 35 mg / cm2

[0027] Cathode, material - high-nickel ternary (NCM811) - areal density 20 - 28 mg / cm2

[0028] Refer to relevant empirical values to set the initial flow rate of each nozzle (an excessive flow rate will cause the coating to accumulate and adhere to the subsequent pressing roller, thereby destroying the coating consistency); set the threshold value for the displacement regulation of the first pressing roller shaft (to prevent excessive tension in the electrode caused by excessive displacement, resulting in electrode breakage); specify the drying temperature threshold (to prevent insufficient bonding strength between the coating and the substrate due to too low a temperature, generating waste pieces).

[0029] During the coating process, for the consistency of the front and rear thickness, the following adjustment process is carried out:

[0030] The substrate unwinding unit unfolds the substrate. After the first coating by the first coating module strip 7, the areal density is detected by the first areal density detection strip 6. According to the deviation between the average areal density at this point and the set areal density, the pressing distance of the first pressing roller 4 is adjusted for compensation. If the adjustment of the pressing distance of the first pressing roller 4 to the limit is still insufficient for compensation, the flow rate of each nozzle on the first coating module strip 7 is adjusted.

[0031] Adjust the flow rate of the nozzles at the corresponding positions of the second coating module strip 5 according to the fluctuation of the surface density at different positions in the cross-cutting direction of the conveyor belt for compensation; if the adjustment of the flow rate of the nozzles at the corresponding positions of the second coating module strip 5 to the limit is still insufficient for compensation, increase the drying temperature and at the same time adjust the flow rate of the nozzles at the corresponding positions on the first coating module strip 7;

[0032] After the electrode coil after the first coating is pressed by the first pressing roller 4, it undergoes secondary coating through the second coating module strip 5, and then the surface density is detected by the second surface density detection strip 3. The pressing distance of the second pressing roller 2 is adjusted for compensation according to the deviation between the average surface density at this position and the set surface density;

[0033] The electrode coil after being pressed by the second pressing roller 2 enters the oven for heating and drying, and after drying, it is wound into an electrode coil finished product by the winding mechanism.

[0034] If the deviation between the average surface density after the first coating and the set surface density exceeds the preset threshold value, the controller adjusts the winding speed of the winding mechanism to change the relaxation process of the slurry.

[0035] Specifically, the device adopts a hierarchical coating strategy to improve the coating surface density accuracy. The device sets the coating amount of the first coating module strip 7 to 70% and the coating amount of the second coating module strip 5 to 30%. The reason for adopting the hierarchical coating strategy is that for the pole pieces produced by single coating, the coating surface density is mainly affected by the amount of material fed by the nozzle at one time. For the already coated pole pieces, only by improving the thickness consistency can the adverse effects due to inconsistent surface density be offset. By adopting a two-stage coating scheme, the amount of material fed in the second coating can be adjusted to obtain a higher-precision coating surface density. The reason for adopting the unequal coating strategy is that the coating amount in the second coating is less, so the surface density fluctuation caused by the systematic error in the second coating will be correspondingly reduced due to the smaller total coating amount, and it is easy to improve the quality of the pole pieces and obtain qualified samples by improving the thickness consistency.

[0036] Coating flow rate = substrate traveling speed × coating width × surface density. The initial displacement of the pressing roller is set respectively according to a 50% pressing rate. Due to different coating amounts, the pressing displacements of the first and second stage coating pressing rollers are also different. Set the initial drying temperature of the oven.

[0037] During coating, if the discharging speed at the coating port fluctuates, it will cause the coating at this coating port part: 1. The surface density is too high 2. The coating thickness is too thick. During the coating process, the control system makes the following adjustment processes respectively for the coating surface density and thickness consistency:

[0038] Regarding the coating areal density of the electrode, the control system regulates it by controlling the front and rear two-stage nozzles. First, the substrate enters the first coating according to the set initial value. After the nozzle completes the first coating, through the first-stage areal density detection, at this time the electrode has not been pressed, and the areal density and thickness information can be obtained. The sampled values are uploaded to the control system. The control system controls the flow rate of the second-stage coating according to the areal density sampled values. For the inconsistent areal density in the transverse coating, the second coating module strip 5 will regulate the opening degree of the corresponding nozzle valve to increase or decrease the second coating amount at this position. For the inconsistent areal density in the longitudinal direction, the pressing distance of the first pressing roller 4 is adjusted for compensation. If the adjustment of the pressing distance of the first pressing roller 4 reaches the limit and is still insufficient for compensation, the flow rates of the nozzles on the first coating module strip 7 are adjusted.

[0039] If it passes the second-stage areal density detection and confirms that the actual areal density after the second-stage coating is within the allowable error range of the set value. The displacement of the second-stage pressing roller follows the principle of consistent thickness, and its downward pressing displacement remains unchanged.

[0040] The temperature control module gives feedback on the second-stage areal density detection and regulates the drying temperature according to the surface areal density. If the local areal density in the second-stage areal density detection value is on the high side, auxiliary adjustment is carried out through the temperature control module. The temperature control module increases the drying temperature, the deformation resistance of the electrode coating decreases, making the surface thickness of the electrode uniform. At the same time, a higher drying temperature is conducive to the transfer of the binder and water inside the coating, improving the areal density consistency. After the area with high areal density leaves the drying module, the auxiliary adjustment ends and enters the normal drying process. If there is no abnormal value in the second-stage areal density detection, it works according to the normal drying process, adapts to the feeding amount of the second-stage nozzles, and the control system makes a follow-up adjustment to the drying temperature.

[0041] The maximum downward pressing amount of the feedback compensation of the pressing roller is determined according to the strength of the electrode. When the pressing roller presses down excessively, the stress of the electrode is too large and the electrode will break. The maximum displacement of the pressing roller is within the safe stress of the electrode. Its minimum downward pressing amount should maintain the surface tension of the electrode to prevent coating unevenness caused by wrinkling on the surface of the electrode. When the displacement amount of the pressing roller approaches the displacement threshold, at this time, the nozzle gives feedback compensation, regulates the feeding speed to a reasonable value, and the pressing roller returns to the normal adjustment area according to the above program to prevent coating failure caused by excessive displacement of the pressing roller.

[0042] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a system, or a computer program product. Therefore, the present invention can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0043] The present invention is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to embodiments of the present invention. It should be understood that each flow and / or block in the flowchart and / or block diagram, as well as the combination of flows and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in one flow Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0044] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing devices to work in a specific manner, such that the instructions stored in the computer-readable memory generate a manufactured article including instruction means that implement the functions specified in one flow Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0045] These computer program instructions can also be loaded onto a computer or other programmable data processing devices, such that a series of operation steps are executed on the computer or other programmable devices to generate a computer-implemented process, so that the instructions executed on the computer or other programmable devices provide steps for implementing the functions specified in one flow Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0046] Assembling the above method steps into a program and then storing it on a hard disk or other non-transitory storage medium constitutes an embodiment of the "non-transitory readable recording medium" of the present invention; and electrically connecting the storage medium to a computer processor and being able to complete the coating of the battery electrode coil through data processing constitutes an embodiment of the "battery electrode coil coating system" of the present invention.

[0047] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A battery electrode coil coating device, characterized in that It includes a base material unwinding unit, a transmission line, an oven, and a winding mechanism connected in sequence. The transmission line includes a first coating module strip, a first surface density detection strip, a first pressing roller, a second coating module strip, a second surface density detection strip, and a second pressing roller that are arranged parallel to each other in the transmission direction between the base material unwinding unit and the oven. It also includes a controller electrically connected to the temperature sensor and temperature control module in the oven, and the controller is also electrically connected to the first coating module strip, the first surface density detection strip, the first pressing roller, the second coating module strip, the second surface density detection strip, and the second pressing roller respectively.

2. The battery electrode coil coating device according to claim 1, characterized in that, The controller is also electrically connected to the winding mechanism for controlling the winding speed.

3. The battery electrode coil coating device according to claim 2, characterized in that, Both the first coating module strip and the second coating module strip are single-row spraying module configurations, and the distance between adjacent nozzles is 20 mm - 50 mm.

4. A method for coating a battery electrode coil, using the battery electrode coil coating device according to any one of claims 1 - 3, and completing the following steps: S1. Set the coating surface density according to the coating material, allocate the coating amounts of the first coating module strip and the second coating module strip, and set the initial slurry flow rate of each nozzle and the initial displacement amount of the pressing roller. S2. The base material unwinding unit unfolds the base material. After the first coating is performed by the first coating module strip, the surface density is detected by the first surface density detection strip. The downward pressure distance of the first pressing roller is adjusted for compensation according to the deviation between the average surface density at this location and the set surface density. If the downward pressure distance of the first pressing roller is adjusted to the limit and is still insufficient for compensation, then the flow rate of each nozzle on the first coating module strip is adjusted. S3. Adjust the flow rate of the nozzles at the corresponding positions of the second coating module strip for compensation according to the fluctuation of the surface density at different positions in the cross-cutting direction of the conveyor belt. If the flow rate of the nozzles at the corresponding positions of the second coating module strip is adjusted to the limit and is still insufficient for compensation, then increase the drying temperature, and at the same time adjust the flow rate of the nozzles at the corresponding positions on the first coating module strip. S4. The electrode coil after the first coating is pressed by the first pressing roller and then undergoes a second coating by the second coating module strip, and then the surface density is detected by the second surface density detection strip. The downward pressure distance of the second pressing roller is adjusted for compensation according to the deviation between the average surface density at this location and the set surface density. S5. The electrode coil after being pressed by the second pressing roller enters the oven for heating and drying, and after drying, it is wound by the winding mechanism into a finished electrode coil.

5. A method for coating a battery electrode coil stock according to claim 4, characterized in that, If the deviation between the average surface density after the first coating and the set surface density exceeds the preset threshold, the controller adjusts the winding speed of the winding mechanism to change the relaxation process of the slurry.

6. A non-transitory readable recording medium for storing one or more programs including a plurality of instructions, characterized in that, When the instruction is executed, it will cause the processor to execute the method for coating a battery electrode coil according to claim 5.

7. A battery electrode coil coating system, characterized in that It includes a processing circuit and a memory electrically coupled thereto, characterized in that the memory is configured to store at least one program, the program includes a plurality of instructions, and the processing circuit runs the program and can execute the method for coating a battery electrode coil according to claim 5.

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