Digital printing production method for insulating coating on lithium battery surface

Abstract

The present application provides a method for digitally printing and producing insulating coatings on the surface of lithium batteries, including: UV digital coating, establishing a mapping relationship, finished product inspection, grading and blanking of good products, and repairing defective products. The present application groups and numbers the printing stations for each side of the battery and the multiple nozzles for printing the current side, forming a mapping relationship table between the printing stations, nozzles, and each side of the battery. During finished product inspection, the defect type and defect location information of the insulating coating are obtained. Based on the defect type and defect location information, the mapping relationship table is queried to obtain information about the printing station and nozzle that caused the defect. Then, the process parameters of the corresponding printing station and nozzle are adjusted according to the defect type, thereby realizing the function of timely discovering product defects and automatically responding to the defects, thereby avoiding production waste.

Description

Technical Field

[0001] The present application belongs to the field of battery production technology, and more specifically, relates to a method for digitally printing and producing insulating coatings on the surface of lithium batteries. Background Art

[0002] The rapid development of the new energy vehicle and energy storage markets has driven increased requirements for the insulation performance of lithium battery casings. With the significant increase in operating voltage and energy density, traditional PET blue film insulation solutions are beginning to fail to meet higher levels of safety requirements. PET blue film has weak adhesion properties, especially after long-term use, when environmental factors can cause the adhesive backing of the PET blue film to degrade, posing a safety hazard in high-voltage platform vehicles. During the PET film coating production process, numerous defects such as sub-film bubbles, foreign particles, and uneven coatings are present, resulting in low yields and wasted costs. These defects can also lead to potential risks such as localized overheating, insulation film puncture, and insulation film shedding during the battery's lifecycle.

[0003] To address the problem of preparing insulating coatings on battery surfaces, common process paths in the industry include powder spraying, UV painting, and UV digital coating. UV digital coating offers significant advantages over powder spraying and painting in terms of coating thickness uniformity, raw material utilization, production environment, and energy consumption. However, existing production lines for preparing insulating coatings on battery surfaces lack intelligence, and are unable to detect product defects promptly or respond promptly when defects are discovered, resulting in production waste. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for digitally printing and producing an insulating coating on the surface of a lithium battery, aiming to solve the problem that the existing insulating spraying method has poor effect.

[0005] To achieve the above objectives, the technical solution adopted in this application is to provide a method for digitally printing and producing an insulating coating on the surface of a lithium battery, comprising:

[0006] UV digital coating, applying insulating coating on each side of the battery and curing the insulating coating;

[0007] Establish a mapping relationship, group and number the printing stations that execute each side of the battery and the multiple nozzles that execute the current side printing, and form a mapping relationship table between the printing stations, nozzles and each side of the battery;

[0008] Finished product inspection: inspecting the insulating coating on the surface of the battery to obtain defect types and defect location information of the insulating coating. Based on the defect types and defect location information, querying the mapping relationship table to obtain information about the printing station and print head that caused the defect, so as to adjust the process parameters of the corresponding printing station and print head according to the defect type;

[0009] Quality judgment: According to the results of finished product inspection, the batteries are divided into good and defective products. Good products are graded and cut into batches, and defective products are repaired. After the repair is qualified, the above steps are repeated.

[0010] Optionally, the UV digital painting includes:

[0011] Each surface of the battery to be printed is photographed to obtain bright areas and dark areas. The bright areas are high-reflective areas on the battery surface, and the dark areas are low-reflective areas outside the battery. The edges, top corners, and plane areas of the battery are identified using the bright and dark areas to obtain the contour information of the battery. The battery surface is inkjet printed and cross-linked and cured according to the contour information of the battery to obtain an insulating coating.

[0012] Optionally, the performing inkjet printing on the battery surface according to the battery contour information includes:

[0013] Full surface printing, covering the edges, corners and flat areas of the battery surface with insulating coating;

[0014] Partial printing: spray the edges and corners of the battery with insulating paint to form an insulating coating of preset thickness on the edges and corners of the battery.

[0015] Optionally, the partial printing includes:

[0016] Print and cure the edges and corners to form an additional coating of a certain thickness in the edges and corners; or the printing control system controls the amount of insulating coating sprayed in the edges and corners to be greater than the amount of insulating coating sprayed in the flat area; or the insulating coating is sprayed onto the edges and corners through a spray valve or dispensing process and pre-cured to form a local insulating coating in advance.

[0017] Optionally, the cross-linking and curing comprises:

[0018] Pre-curing, irradiating the insulating coating on the surface of the battery with a first UV light to make the insulating coating lose fluidity, thereby forming a pre-cured layer;

[0019] Final curing: irradiating the pre-cured layer with a second UV light to further complete the photo-induced cross-linking curing reaction of the pre-cured layer until the insulating coating reaches a final stable form, thereby forming the insulating coating.

[0020] Optionally, the finished product inspection includes one or more of coating thickness inspection, appearance inspection, coating insulation withstand voltage performance test and color inspection.

[0021] Optionally, the coating thickness detection includes: measuring the thickness of the insulating coating in the edge and corner areas using a photothermal infrared method, and measuring the thickness of the insulating coating in the plane area using an infrared spectroscopic interferometer. When the thickness data exceeds a set threshold, the printing control system corrects the process parameters of the corresponding printing station and nozzle according to the mapping relationship table.

[0022] Optionally, the appearance inspection includes: using a 2.5D optical imaging system to acquire product images, combining a deep learning algorithm to identify defects in the product images, and locating, quantifying and classifying the defects.

[0023] Optionally, the insulation voltage resistance performance test includes: performing insulation impedance and voltage resistance tests by contacting the surface of the insulating coating with a conductive electrode. If insufficient impedance or voltage resistance breakdown failure occurs, the test station is used to determine on which side of the battery the defect occurs, and the printing control system corrects the process parameters of the corresponding printing station and nozzle according to the mapping relationship table.

[0024] Optionally, when defective products are returned for repair, the location and type of defects on the product are determined based on the feedback of defects and defect location information, and corresponding repair treatment is performed on the defective location based on the defect type; and / or, surface pre-treatment is also included before UV digital painting, and the surface pre-treatment includes one or more of laser cleaning, plasma gas cleaning, sandblasting, chemical reagent cleaning, and dry ice cleaning.

[0025] The beneficial effect of the digital printing production method for the surface insulating coating of lithium batteries provided by this application is that: compared with the existing technology, this application forms a mapping relationship table between the printing stations, nozzles, and each side of the battery by grouping and numbering the printing stations performing each side of the battery and the multiple nozzles performing the current side printing. During the finished product inspection, the defect type and bad location information of the insulating coating are obtained. Based on the defect type and bad location information, the mapping relationship table is queried to obtain information about the printing station and nozzle that caused the defect. Then, the process parameters of the corresponding printing station and nozzle are adjusted according to the defect type, thereby realizing the function of timely discovering product defects and automatically responding to the defects, thereby avoiding production waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0027] Figure 1A schematic diagram of a process for digitally printing an insulating coating on a lithium battery surface provided in an embodiment of the present application;

[0028] Figure 2 Schematic diagram of the thickness of the insulating coating on the battery surface when the edges are not compensated;

[0029] Figure 3 Schematic diagram of the insulating coating thickness on the battery surface under edge compensation conditions. DETAILED DESCRIPTION

[0030] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, this application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0031] It should be noted that when an element is referred to as being “fixed on” or “disposed on” another element, it may be directly on the other element or indirectly on the other element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or indirectly connected to the other element.

[0032] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0033] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0034] In related fields, with the significant increase in operating voltage and energy density, traditional PET blue film insulation solutions are beginning to be unable to meet higher-level safety requirements. The bonding performance of PET blue film is relatively weak, especially after long-term use, when environmental factors cause the bonding performance of the PET blue film backing to deteriorate, posing a safety hazard in high-voltage platform vehicles. During the coating production process, PET film has a large number of defects such as bubbles under the film, foreign particles, and uneven coating, resulting in low yield and cost waste. The above defects can also cause potential risks such as local overheating of the battery during its service life, puncture of the insulation film, and shedding of the insulation film.

[0035] In order to solve the above problems, UV digital spraying process is usually adopted. However, the existing UV digital spraying production line is not smart enough and cannot detect product defects in time or cannot respond in time when product defects are found, resulting in production waste.

[0036] In view of this, the present application provides a method for digital printing of insulating coating on the surface of lithium battery. Figure 1-Figure 3 , the digital printing production method of the lithium battery surface insulating coating provided in the embodiment of the present application is now described.

[0037] A method for digitally printing and producing an insulating coating on the surface of a lithium battery, comprising:

[0038] UV digital coating, applying insulating coating on each side of the battery and curing the insulating coating;

[0039] Establish a mapping relationship, group and number the printing stations that execute each side of the battery and the multiple nozzles that execute the current side printing, and form a mapping relationship table between the printing stations, nozzles and each side of the battery;

[0040] Finished product inspection: inspecting the insulating coating on the surface of the battery to obtain defect types and defect location information of the insulating coating. Based on the defect types and defect location information, querying the mapping relationship table to obtain information about the printing station and print head that caused the defect, so as to adjust the process parameters of the corresponding printing station and print head according to the defect type;

[0041] Quality judgment: According to the results of finished product inspection, the batteries are divided into good and defective products. Good products are graded and cut into batches, and defective products are repaired. After the repair is qualified, the above steps are repeated.

[0042] This application groups and numbers the printing stations for each side of the battery and the multiple nozzles that print the current side, forming a mapping relationship table between the printing stations, nozzles, and each side of the battery. During finished product inspection, the defect type and defect location information of the insulating coating are obtained. Based on the defect type and defect location information, the mapping relationship table is queried to obtain information about the printing station and nozzle that caused the defect. The process parameters of the corresponding printing station and nozzle are then adjusted according to the defect type, thereby achieving closed-loop management of the automated production process and reducing production waste caused by untimely discovery or inability to respond to defects in a timely manner.

[0043] For example, if the finished product inspection station identifies several identical defects at the same time in a certain location on the battery, this information can be automatically fed back to the UV digital coating station. The print control system can query the corresponding print station and nozzle information through a mapping table based on the defect location information, and then change the process parameters of the corresponding print station and nozzle to avoid producing more defective products. For another example, if the finished product inspection station identifies an unacceptable defect in a specific location on the battery, the print control system can pass the defect location information to the defect rework station. The defect rework station can perform a specific rework process based on the defect type, while retaining the remaining non-defective coatings, thereby achieving accurate defect rework.

[0044] In some embodiments of the present application, the printing stations for each side of a square-shell battery (the same applies to cylindrical batteries) and the multiple nozzles that print on that side are grouped and numbered to form a mapping relationship table between the entire printer's stations + nozzles and each side of the product. When the finished product inspection station identifies a printing defect in a specific area of ​​a specific side, the print control system obtains information about the abnormal printing station and nozzle through a query in the mapping relationship table, thereby locating which nozzle in the upstream printing device has the abnormality. The process parameters are then adjusted accordingly based on the defect type, thereby achieving closed-loop management of the automated production process and reducing production waste caused by untimely detection or the inability to respond to defects when they are discovered.

[0045] In some embodiments of the present application, the print control system can configure different handling methods for detected defects based on the defect type (e.g., an ink-missing streak extending across an entire surface) or the quantified result (uneven thickness exceeding a specific area). These methods can include attempting to adjust the print area (by shifting the print head to change the print area), performing automatic printhead cleaning and maintenance, or directly triggering an alarm to interrupt production and indicate the need for manual intervention.

[0046] In some embodiments of the present application, the specific steps of the UV digital painting include:

[0047] Each surface of the battery to be printed is photographed to obtain bright areas and dark areas. The bright areas are high-reflective areas on the battery surface, and the dark areas are low-reflective areas outside the battery. The edges, top corners, and plane areas of the battery are identified using the bright and dark areas to obtain the contour information of the battery. The battery surface is inkjet printed and cross-linked and cured according to the contour information of the battery to obtain an insulating coating.

[0048] Specifically, a vision guidance system photographs each surface of the battery. Light is applied to the edges of the battery product, creating bright areas and dark areas outside the product. This contrast is used to identify contour areas. The edges and corners of the battery reflect more strongly, forming bright areas (defined as bright areas when the grayscale value is greater than a set value). Areas outside the battery reflect less strongly, forming dark areas (defined as dark areas when the grayscale value is less than a set value). The battery surface, excluding the edges and corners, is flat. Therefore, by distinguishing between bright and dark areas, the edges, corners, and flat areas of the battery can be identified, thereby obtaining the battery's contour information. After identifying the contour, a template can be applied based on the contour position to determine the internal structure locations requiring coating clearance. The print control system transmits the relevant control information to the digital printing system for execution, enabling accurate coating of the product surface. The vision guidance system can identify the specific contour details and dimensions of each product, effectively reducing ink waste and poor appearance outside the product contour. It also enables compatibility with digital printing systems within a certain size range, enabling rapid production changeovers.

[0049] In the prior art, see Figure 2 Due to the geometric characteristics of the battery casing's edges and corners, as well as the surface tension of the insulating coating, the coating tends to aggregate toward the flat areas on either side of the edges after being sprayed onto them. This results in insufficient coating thickness in the center of the arc. This microstructure prevents the insulating coating from meeting the required dielectric strength. High voltage will preferentially break down thinner areas.

[0050] In order to compensate for the weak conductive coating problem in the edge and corner areas, the present application performs compensation treatment on the insulating coating in the edge and corner areas to increase the coating thickness at the thinnest point (e.g. Figure 3 As shown), it can meet the insulation withstand voltage requirements and is conductive above the minimum thickness.

[0051] In some embodiments of the present application, the step of printing the insulating coating includes:

[0052] Full surface printing, covering the edges, corners and flat areas of the battery surface with insulating coating;

[0053] Partial printing: Re-spray the edges and corners of the battery with insulating paint to form an insulating coating with a preset thickness (pre-set thickness, at which the insulating coating can meet the insulation withstand voltage requirements) on the edges and corners of the battery.

[0054] By partially printing the insulating coating on the edges and corners of the battery, the insulating coating on the edges and corners is compensated to increase the thickness of the insulating coating at the thinnest point so that it can meet the insulation withstand voltage requirements.

[0055] In some embodiments of the present application, the entire surface may be printed first, and then the edges and corners may be partially printed. In other embodiments of the present application, the edges and corners may be partially printed first, and then the entire surface may be printed.

[0056] In some embodiments of the present application, partial printing can be performed multiple times, for example, two or three times. The number of partial printings depends on the insulation withstand voltage requirements for the thinnest coating, or the effect of the geometric characteristics of edges and corners on the ink thickness. For example, with smoother and more rounded edges, the difference in thickness between the center region and the flat surface will be slightly smaller. With sharper edges, the difference in thickness between the center region and the flat surface will be greater, and more partial printings may be required.

[0057] In some embodiments of the present application, by printing and curing the edges and corners, a coating of a certain thickness is additionally formed in the edges and corners, thereby achieving local printing.

[0058] In other embodiments of the present application, a print control system controls the amount of insulating coating sprayed in edge and corner areas to be greater than that in planar areas, thereby achieving partial printing. This can be accomplished by deleting pixels in planar areas according to certain rules (also called "point extraction") in the printed image, so that the number and density of pixels in planar areas are smaller than those in edge and corner areas. Alternatively, the grayscale of the image can be set to a lower grayscale in planar areas and a higher grayscale in edge and corner areas. During printing, smaller grayscales result in smaller ink droplets, while larger grayscales result in larger ink droplets. This can also create a difference in the amount of insulating coating sprayed, compensating for thickness in edge and corner areas.

[0059] In other embodiments of the present application, the insulating coating is sprayed onto the edges and corners and pre-cured through a spray valve or a dispensing process to form a local insulating coating in advance, thereby achieving local printing.

[0060] Table 1 Comparison of thickness of the thinnest part of different edge local printing states

[0061]

[0062] Table 1 is a comparison of the thickness at the thinnest position of three different edges in Examples 1-3 without local printing and after 1, 2, and 3 local printings respectively. It can be seen from the data in the table that the local printing method can effectively compensate for the insulating coating in the edges and top corner areas to increase the thickness of the insulating coating at the thinnest point so that it can meet the insulation withstand voltage requirements, and the more times the local printing is performed, the thicker the insulating coating is.

[0063] In some embodiments of the present application, the step of cross-linking and curing the insulating coating printed on the surface of the product includes:

[0064] Pre-curing: using UV light to make the insulating coating printed on the battery surface lose its fluidity and form a preliminary cure;

[0065] Final curing: UV light is used to fully complete the photo-induced cross-linking curing of the insulating coating on the surface of the battery, so that the insulating coating reaches the final stable form and forms an insulating coating.

[0066] Specifically, in some specific embodiments, pre-curing can be performed using UV light with an energy density of 100-2000 mJ / cm² to achieve a preliminary cure (only loss of liquid fluidity) of the insulating coating printed on the product surface, preventing further uncontrolled flow (sagging) of the insulating coating and ensuring the uniform appearance of the final coating. Final curing can be performed using UV light with an energy density of 10,000-40,000 mJ / cm² to fully complete the photo-induced cross-linking of the insulating coating on the battery surface, achieving its final stable state.

[0067] In some embodiments of the present application, the finished product inspection includes one or more of coating thickness inspection, appearance inspection, coating insulation withstand voltage performance test and color inspection.

[0068] In some embodiments of the present application, the coating thickness detection includes: measuring the thickness of the insulating coating in the edge and top corner areas using a photothermal infrared method, and measuring the thickness of the insulating coating in the plane area using an infrared spectroscopic interferometer. When the thickness data exceeds a set threshold, the printing control system corrects the process parameters of the corresponding printing station and nozzle according to the mapping relationship table.

[0069] Photothermal infrared thickness measurement technology is compatible with irregularly shaped surfaces (edges, arcs, vertices, and curved surfaces), and has minimal restrictions on probe installation (measurements can be made within a ±70° range, effectively preventing mechanical precision from interfering with the measurement results). Infrared interferometry is used for coating thickness measurement on flat surfaces, achieving high precision and a high sampling frequency. This allows for scanning measurements of scribed lines on a flat surface, thereby measuring the coating thickness along the scribed line. When thickness data exceeds a set threshold, the print control system automatically adjusts the printing device's process parameters using a mapping table. For example, if the insulation coating thickness at a certain nozzle location across the width of a surface is below average, the software can automatically adjust the operating voltage of that nozzle to compensate. For example, if the insulation coating thickness at an edge is detected to be significantly below the set threshold, an alarm can be issued to the corresponding workstation, prompting manual intervention.

[0070] In some embodiments of the present application, the appearance inspection includes: using a 2.5D optical imaging system to obtain product images, combining a deep learning algorithm to identify defects in the product images, and locating, quantifying and classifying the defects.

[0071] Specifically, a visual system can capture images of product surface features, then use deep learning algorithms to extract, classify, and quantify defect features within these images. For example, this can identify whether there are raised particles or pits on the coating surface, or whether there are localized ink gaps in the insulating coating. Image recognition is performed by leveraging the differences in grayscale contrast and morphological features between the images formed by different defects under specific exposure conditions. This algorithmic recognition can identify defects directly related to printing, such as ink gaps and broken frames.

[0072] In some embodiments of the present application, the insulation voltage resistance performance test includes: performing insulation impedance and voltage resistance tests by contacting the surface of the insulating coating with a conductive electrode. If insufficient impedance or voltage resistance breakdown failure occurs, the test station is used to determine on which side of the battery the defect occurs, and the printing control system corrects the process parameters of the corresponding printing station and nozzle according to the mapping relationship table.

[0073] In some embodiments of the present application, the frequency of defect occurrence can be set. For example, if 7 (the specific number can be set) defects appear continuously on a certain surface, the printing control system will issue an alarm to the printing station of this surface to prompt manual intervention.

[0074] In some embodiments of the present application, when defective products are repaired, the location and type of defects on the product are determined based on the feedback of defects and defective location information, and corresponding repairs are performed on the defective locations based on the defect types. The prior art uses laser cleaning to remove the insulating coating on all surfaces of the defective product and then re-print it. After adopting this solution, when the finished product inspection station detects an unacceptable defect at a specific location, the location information can be transmitted to the defective product repair station, and the printing control system can execute a specific repair process based on the defect location information, while retaining the remaining insulating coatings that do not have defects, thereby achieving accurate defective product repair, saving resources and improving efficiency.

[0075] In some embodiments of the present application, surface pretreatment is also included before UV digital painting, and the surface pretreatment includes but is not limited to laser cleaning, plasma gas cleaning, sandblasting, chemical reagent cleaning, and dry ice cleaning.

[0076] In some embodiments of the present application, a laser is used to perform ablation cleaning on the shell surface, vacuum dust removal is applied at the cleaning position, and then the shell surface is subjected to plasma treatment.

[0077] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A method for digitally printing and producing an insulating coating on the surface of a lithium battery, characterized in that: include: UV digital coating, applying insulating coating on each side of the battery and curing the insulating coating; Establish a mapping relationship, group and number the printing stations that execute each side of the battery and the multiple nozzles that execute the current side printing, and form a mapping relationship table between the printing stations, nozzles and each side of the battery; Finished product inspection: inspecting the insulating coating on the surface of the battery to obtain defect types and defect location information of the insulating coating. Based on the defect types and defect location information, querying the mapping relationship table to obtain information about the printing station and print head that produced the defect type, so as to adjust the process parameters of the corresponding printing station and print head according to the defect type; Quality judgment: According to the results of finished product inspection, the batteries are divided into good and defective products, the good products are graded and cut into pieces, and the defective products are repaired. After the repaired products are qualified, the above steps are repeated; Wherein, the UV digital coating includes: Taking a photo of each surface of the battery to be printed to obtain bright areas and dark areas, wherein the bright areas are high-reflective areas on the battery surface, and the dark areas are low-reflective areas outside the battery. The edges, corners, and plane areas of the battery are identified using the bright and dark areas to obtain battery contour information. Inkjet printing is performed on the battery surface based on the battery contour information, and cross-linking and curing is performed to obtain an insulating coating. The inkjet printing on the battery surface according to the battery contour information includes: Full surface printing, covering the edges, corners and flat areas of the battery surface with insulating coating; Partial printing: spray the insulating coating on the edges and corners of the battery to form an insulating coating of preset thickness on the edges and corners of the battery; The finished product inspection includes one or more of coating thickness inspection, appearance inspection, coating insulation withstand voltage performance test and color inspection.

2. The method for digitally printing and producing the insulating coating on the surface of a lithium battery according to claim 1, characterized in that: The local printing includes: Print and cure the edges and corners to form an additional coating of a certain thickness in the edges and corners; or the printing control system controls the amount of insulating coating sprayed in the edges and corners to be greater than the amount of insulating coating sprayed in the flat area; or the insulating coating is sprayed onto the edges and corners through a spray valve or dispensing process and pre-cured to form a local insulating coating in advance.

3. The method for digitally printing and producing the insulating coating on the surface of a lithium battery according to claim 1, characterized in that: The cross-linking and curing comprises: Pre-curing, irradiating the insulating coating on the surface of the battery with a first UV light to make the insulating coating lose fluidity, thereby forming a pre-cured layer; Final curing: irradiating the pre-cured layer with a second UV light to further complete the photo-induced cross-linking curing reaction of the pre-cured layer until the insulating coating reaches a final stable form, thereby forming the insulating coating.

4. The method for digitally printing and producing the insulating coating on the surface of a lithium battery according to claim 1, characterized in that: The coating thickness detection includes: measuring the thickness of the insulating coating in the edge and corner areas using a photothermal infrared method, and measuring the thickness of the insulating coating in the plane area using an infrared spectroscopic interferometer. When the thickness data exceeds a set threshold, the printing control system corrects the process parameters of the corresponding printing station and nozzle according to the mapping relationship table.

5. The method for digitally printing and producing the insulating coating on the surface of a lithium battery according to claim 1, characterized in that: The appearance inspection includes: using a 2.5D optical imaging system to obtain product images, combining a deep learning algorithm to identify defects in the product images, and locating, quantifying and classifying the defects.

6. The method for digitally printing and producing the insulating coating on the surface of a lithium battery according to claim 4, characterized in that: The insulation and voltage resistance performance test includes: performing insulation impedance and voltage resistance tests by contacting the surface of the insulating coating with a conductive electrode. If insufficient impedance or voltage resistance breakdown failure occurs, the test station is used to determine on which side of the battery the defect occurs, and the printing control system corrects the process parameters of the corresponding printing station and nozzle according to the mapping relationship table.

7. The method for digitally printing and producing a lithium battery surface insulating coating according to claim 1, characterized in that: When defective products are returned for repair, the location and type of defects on the product are determined based on the feedback of defects and defect location information, and corresponding repair treatment is performed on the defective location based on the defect type; and / or, surface pre-treatment is also included before UV digital painting, and the surface pre-treatment includes one or more of laser cleaning, plasma gas cleaning, sandblasting, chemical reagent cleaning, and dry ice cleaning.

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