Pretreatment process for improving jet printing yield of insulating layer on surface of battery cell

Abstract

The invention discloses a pretreatment process for improving the jet printing yield of an insulating layer on the surface of a battery cell, and the pretreatment process comprises the following steps: S1, carrying out texturing treatment on the surface of the battery cell by adopting flat-top laser, keeping a specific area of the battery cell, and carrying out dust removal treatment on the surface of the battery cell while carrying out texturing treatment; and S2, carrying out plasma cleaning treatment on the battery cell with the textured surface. The pretreatment process can improve the roughness and efficiency of surface texturing treatment of the battery cell, so that the adhesive force of the surface of the battery cell is improved, it is guaranteed that aluminum powder on the surface of the battery cell is thoroughly removed, then appearance defects such as white spots and hard spots on the surface of the battery cell subjected to spray printing of an insulating layer are avoided, and the insulation and pressure resistance performance and the structural strength of the insulating layer are improved.

Description

Technical Field

[0001] The present application relates to the technical field of battery production technology, and in particular to a pre-treatment process for improving the printing yield of an insulating layer on the surface of a battery cell. Background Art

[0002] In order to ensure the safety and stability of the power battery system, avoid short circuits and safety accidents, and extend the service life of the power battery system, the surface of the power battery is generally insulated. Traditional single-cell power batteries use a coating process for insulation protection, that is, polymer materials such as PET films are cut into shapes suitable for the size of the battery cell and wrapped on the surface of the battery cell. However, the insulation layer formed by the coating does not meet the standards in terms of insulation withstand voltage performance and structural strength, and is prone to breakdown in high-voltage fast charging platforms and CTP non-modular structures, posing a safety hazard.

[0003] To this end, the existing technology uses a method of printing an insulating layer on the surface of the battery cell to improve the strength. In addition, in order to avoid the appearance of white spots and pitting on the surface of the battery cell after printing, and to avoid the low shear force and weather resistance of the insulating layer, the surface of the battery cell needs to be pre-treated before printing to remove oil stains, electrolytes and other substances that may exist on the surface of the battery cell, and at the same time increase the roughness and adhesion of the surface of the battery cell. At present, the pre-treatment process includes several methods such as sandblasting pre-treatment, chemical treatment and laser roughening. Among them, the sandblasting pre-treatment increases the roughness of the surface of the battery cell by sandblasting, but the sandblasting sand is difficult to control and it is difficult to ensure the consistency of the surface treatment of the battery cell; and the sandblasting pre-treatment is difficult to accurately avoid the pole, explosion-proof valve and QR code on the pole surface of the battery cell, and it is necessary to add a cover plate to shield, which complicates the sandblasting process; in addition, the sand is a consumable material and has the defect of high energy consumption. Chemical treatment increases the roughness of the cell surface through the corrosive and oxidative properties of chemical solutions. However, chemical treatment is highly polluting and requires drying and heating. The entire process is difficult to control and it is difficult to accurately avoid the poles, explosion-proof valves and QR codes on the pole surface of the cell. In comparison, laser texturing can accurately avoid the poles, explosion-proof valves and QR codes on the pole surface of the cell, without pollution, drying and other problems, and can ensure the consistency of the cell surface treatment. It is a more feasible pre-treatment process.

[0004] The existing laser texturing pre-treatment process uses Gaussian laser for texturing, and the poles, explosion-proof valves and QR codes on the pole surfaces of the battery cells are avoided by scanning the contours of the Gaussian laser, and the aluminum powder generated by laser texturing on the surface of the battery cells is removed by blowing with a positive pressure air knife and exhausting with a negative pressure. However, Gaussian laser texturing has the defects of low efficiency, and the positive pressure air knife blowing is difficult to control, which can easily blow the aluminum powder around and exceed the range of the negative pressure exhaust, causing secondary pollution of the aluminum powder, resulting in the inability to completely remove the aluminum powder, resulting in white spots, pitting and other appearance defects on the surface of the battery cell after printing, and affecting the insulation withstand voltage performance and structural strength of the printed insulation layer. Summary of the invention

[0005] In order to solve the above-mentioned defects in the prior art, the purpose of the present application is to provide a pre-treatment process for improving the printing yield of the insulating layer on the surface of the battery cell, so as to improve the roughness and efficiency of the roughening treatment on the surface of the battery cell, thereby improving the adhesion of the surface of the battery cell, and ensuring that the aluminum powder on the surface of the battery cell is completely removed, thereby avoiding the appearance defects such as white spots and pitting on the surface of the battery cell after printing the insulating layer, and improving the insulation withstand voltage performance and structural strength of the insulating layer.

[0006] The present application provides a pre-treatment process for improving the printing yield of the insulating layer on the surface of a battery cell, comprising the following steps:

[0007] S1. Use flat-top laser to roughen the surface of the battery cell and avoid specific areas of the battery cell, and remove dust from the surface of the battery cell during the roughening process;

[0008] S2. Plasma cleaning is performed on the battery cell with a roughened surface.

[0009] As a preferred embodiment, in the present application, in step S1, the texturing treatment adopts a flat-top laser flying process, the laser galvanometer of the laser used to provide the flat-top laser is fixed, the flat-top laser is emitted linearly in a specific direction and with specific energy, and the battery cell moves along a preset path so that its surfaces are texturing treated in turn, and specific areas of the battery cell are avoided.

[0010] As a preferred implementation, in the present application, the specific area includes at least one of the pole of the battery cell, the QR code, the explosion-proof valve, and the blank area surrounding the three.

[0011] As a preferred embodiment, in the present application, a visual positioning device is used to identify specific areas of the battery cell and transmit the identification to a control system, so that the control system can control the texturing process to avoid the specific areas.

[0012] As a preferred embodiment, in the present application, in step S1, the dust removal treatment adopts a negative pressure dust extraction method, and the negative pressure dust suction nozzle of the dust removal equipment is aimed at the roughened surface of the battery cell, and the negative pressure dust suction nozzle is flat.

[0013] As a preferred embodiment, in the present application, in step S2, a plasma gas flow is blown toward the roughened surface of the battery cell to perform a plasma cleaning treatment on the battery cell.

[0014] As a preferred embodiment, in the present application, before the plasma cleaning treatment, the battery cell with the roughened surface is subjected to at least one negative pressure dust removal treatment.

[0015] As a preferred embodiment, in the present application, during the negative pressure dust removal process, the dust removal nozzle of the negative pressure dust removal equipment is aligned with the roughened surface of the battery cell, and the dust removal nozzle is a flared structure.

[0016] As a preferred embodiment, in the present application, during the entire process of the pre-treatment process, explosion-proof treatment is performed by installing explosion-proof equipment on each pipeline.

[0017] As a preferred embodiment, in the present application, the explosion-proof treatment includes providing a flame arrester on each pipeline;

[0018] And / or, the explosion-proof treatment includes setting a negative pressure gauge and anemometer on the pipeline to detect the pressure and wind speed of the pipeline in real time, and controlling whether to alarm by whether the pressure and wind speed reach the set threshold;

[0019] And / or, the explosion-proof treatment includes installing spark detection probes on pipelines and equipment, and controlling whether the fire extinguishing device is activated based on whether the spark detection probes detect sparks.

[0020] The pre-treatment process provided in this application for improving the printing yield of the insulating layer on the surface of the battery cell has the following technical effects:

[0021] The roughening treatment of the cell surface adopts a flat-top laser. The center energy of the flat-top laser is the same as the edge energy, which can evenly roughen the cell surface and avoid damage to the cell surface, thereby improving the efficiency and roughness of the cell surface roughening treatment, and ensuring the consistency of the roughness, which is conducive to improving the adhesion of the cell surface. The roughening treatment of the cell surface is carried out simultaneously with the dust removal treatment, which can remove the aluminum powder generated by the roughening treatment in time. Combined with the subsequent plasma cleaning treatment, it can ensure that the aluminum powder on the cell surface is completely removed, thereby avoiding the appearance defects such as white spots and pitting on the cell surface after the printing of the insulation layer, and improving the insulation withstand voltage performance and structural strength of the insulation layer. DETAILED DESCRIPTION

[0022] In order to better understand and implement, the technical solutions in the embodiments of the present application will be clearly and completely described below.

[0023] In the description of the present application, it should be noted that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. indicate directions or positional relationships that are commonly known and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present application.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0025] The present application provides a pre-treatment process for improving the printing yield of the insulating layer on the surface of the battery cell. The pre-treatment process is used to pre-treat the surface of the battery cell, or pre-treat it, before printing the insulating layer on the surface of the battery cell, so as to remove oil stains, electrolyte, oxide layer, etc. that may exist on the surface of the battery cell, and increase the roughness and adhesion of the surface of the battery cell, thereby avoiding the appearance defects such as white spots and pitting on the surface of the battery cell after printing the insulating layer, and avoiding the low performance of the insulating layer such as shear force and weather resistance, and ensuring the insulating withstand voltage performance and structural strength of the insulating layer.

[0026] Based on this, the pre-treatment process of this application includes the following steps:

[0027] S1. Use flat-top laser to roughen the surface of the battery cell and avoid specific areas of the battery cell, and remove dust from the surface of the battery cell during the roughening process;

[0028] S2. Plasma cleaning is performed on the battery cell with a roughened surface.

[0029] In step S1, the purpose of roughening the surface of the battery cell is to remove the oil, electrolyte, oxide layer, etc. that may exist on the surface of the battery cell, and to increase the roughness and adhesion of the surface of the battery cell. The prior art generally adopts three means, namely sandblasting, chemical treatment and laser roughening. For sandblasting, it increases the roughness of the surface of the battery cell by sandblasting, but the sand blasting sand is difficult to control and it is difficult to ensure the consistency of the surface treatment of the battery cell; and it is difficult to accurately avoid the pole, explosion-proof valve and QR code on the pole surface of the battery cell before sandblasting, and it is necessary to increase the cover plate shielding, which complicates the sandblasting process; in addition, the sand is a consumable material and has the defect of high energy consumption. For chemical treatment, it increases the roughness of the surface of the battery cell through the corrosive and oxidizing properties of the chemical solution, but the chemical treatment is more polluting, and the surface of the battery cell needs to be dried and heated. The whole process is difficult to control, and it is difficult to accurately avoid the pole, explosion-proof valve and QR code on the pole surface of the battery cell.

[0030] Compared with the defects of sandblasting, such as poor consistency of surface roughness of battery cells, inability to accurately avoid gaps on the battery cell pole surface, complex process, high energy consumption, and chemical treatment, which is highly polluting, complicated process due to drying, and inability to accurately avoid gaps on the battery cell pole surface, the texturing treatment in this application adopts a laser texturing treatment process, which can not only accurately avoid gaps on the battery cell pole surface, but also has a simple process, no pollution, low energy consumption, and is beneficial to improving the consistency of the surface roughness of the battery cell.

[0031] As for laser roughening, the existing technology generally uses Gaussian laser for roughening, and the poles, explosion-proof valves and QR codes on the pole surface of the battery cell are avoided by scanning the contour of the Gaussian laser. However, Gaussian laser has the characteristics of high center energy and low edge energy. When roughening the surface of the battery cell, the center energy is higher than the damage threshold of the battery cell surface, which can easily cause damage to the battery cell surface. The edge energy is lower than the cleaning threshold of pollutants such as oil, electrolyte, and oxide layer, resulting in the edge energy being unable to completely remove pollutants on the surface of the battery cell. In addition, the high center energy of the Gaussian laser can easily produce tiny burrs on the surface of the battery cell, thereby reducing the insulation withstand voltage performance and structural strength after the insulation layer is printed. The roughening treatment of the cell surface in this application uses a flat-top laser. The center energy of the flat-top laser is the same as the edge energy and the energy is moderate. It can evenly roughen the cell surface and completely remove oil, electrolyte, oxide layer and other pollutants on the cell surface. The amount of aluminum powder produced is small and damage to the cell surface is avoided, thereby improving the efficiency and roughness of the roughening treatment on the cell surface, and ensuring the consistency of the roughness, which is conducive to improving the adhesion of the cell surface. In addition, the flat-top laser roughening treatment will not produce tiny burrs on the cell surface, thereby ensuring the insulation withstand voltage performance and structural strength after the printing of the insulation layer.

[0032] While the flat-top laser roughening treatment is being performed, the present application also performs dust removal treatment on the roughened position on the surface of the battery cell, which can remove the aluminum powder generated by the roughening treatment in time. Combined with the plasma cleaning treatment in step S2, it can ensure that the aluminum powder on the surface of the battery cell is completely removed, thereby avoiding the appearance defects such as white spots and pitting on the surface of the battery cell after the insulation layer is printed, and improving the insulation withstand voltage performance and structural strength of the insulation layer.

[0033] It should be noted that the pre-treatment process is an automated process. By developing an automated control program and setting the process parameters, the control system is used to control the orderly progress of each step.

[0034] On this basis, in step S1, the roughening treatment adopts the flat-top laser flying process, the laser galvanometer of the laser used to provide the flat-top laser is fixed, the flat-top laser is emitted in a linear form with a specific direction and specific energy, and the battery cell moves along a preset path so that each surface thereof is roughened in turn, and avoids the specific area of ​​the battery cell. That is, the laser galvanometer is controlled to be fixed, and the flat-top laser is controlled to be emitted in a linear form of a line, and the flat-top laser is used to roughen each surface of the battery cell by moving the battery cell. Taking the square battery cell as an example, each surface includes two relatively large surfaces of the battery cell, two relatively side surfaces, and the top and bottom surfaces. All six surfaces need to be roughened, and on the basis of the laser galvanometer being fixed and the flat-top laser being emitted in a linear form with a specific direction and specific energy, the battery cell is controlled to move so as to roughen the six surfaces of the battery cell in turn.

[0035] In the prior art, laser roughening generally uses a contour-scanning method to keep the battery cell stationary and use the laser to move to roughen the surface of the battery cell, so that the range of aluminum powder generated on the surface of the battery cell is large, the range of dust removal during roughening is large, and the dust removal device needs to cover a large range, resulting in a low dust removal wind speed, poor dust removal effect, and not conducive to the timely removal of aluminum powder, thereby affecting the appearance of the printed insulation layer and the insulation withstand voltage performance, structural strength, etc. In the flat-top laser flight process of the present application, the flat-top laser light output is fixed, and the movement of the battery cell is controlled to achieve roughening. Since the flat-top laser is linear, the range of aluminum powder generated on the surface of the battery cell during roughening is small, which greatly reduces the range of dust removal during roughening, and can quickly remove the aluminum powder generated by roughening, thereby avoiding the appearance defects such as white spots and pitting on the surface of the battery cell after the insulation layer is printed, and improving the insulation withstand voltage performance and structural strength of the insulation layer. In addition, it is beneficial to improve the efficiency of the roughening process and simplify the roughening process path.

[0036] It should be noted that during the texturing process, it is necessary to control the light output parameters of the flat-top laser and the movement parameters of the battery cell, and to coordinate the two to achieve efficient texturing of the battery cell surface. No specific limitation is made on the parameters here. The parameter settings vary according to different actual working conditions and can be set according to the texturing requirements.

[0037] The specific area includes at least one of the poles, QR codes, explosion-proof valves, and blank areas surrounding the three. The air avoidance treatment can avoid damage to the specific area, thereby ensuring the normal performance of the battery cell. The present application uses a visual positioning device to identify the specific area of ​​the battery cell and transmit it to the control system, so as to control the roughening treatment to avoid the specific area through the control system. A CCD visual positioning station is set in the entire pre-treatment process system, and in conjunction with the control program, it can timely identify the specific area of ​​the battery cell, thereby avoiding the specific area from being roughened.

[0038] In step S1, the dust removal process adopts a negative pressure dust extraction method, and the negative pressure dust suction nozzle of the dust removal equipment is aimed at the roughened surface of the battery cell, and the negative pressure dust suction nozzle is flat.

[0039] In the prior art, while laser roughening is being processed, the aluminum powder generated by laser roughening on the surface of the battery cell is removed by blowing with a positive pressure air knife in combination with negative pressure exhaust. However, the positive pressure air knife blowing is difficult to control, and it is easy to blow the aluminum powder to the surroundings and exceed the range of negative pressure exhaust, causing secondary pollution of the aluminum powder, resulting in the inability to completely remove the aluminum powder, thereby causing white spots, pitting and other appearance defects on the surface of the battery cell after spray printing, and affecting the insulation withstand voltage performance and structural strength of the spray-printed insulation layer. In the present application, while flat-top laser roughening is being processed, the surface of the battery cell is subjected to dust removal by means of negative pressure exhaust, and the aluminum powder generated by roughening can be removed in time. In addition, since the flat-top laser is linear, the range of aluminum powder generated on the surface of the battery cell during roughening is small, which greatly reduces the range of simultaneous dust removal during roughening. The negative pressure suction nozzle can be set to a flat structure, which is conducive to increasing the wind speed at the suction nozzle, so that the aluminum powder generated by roughening can be removed in time, and there is no influence of positive pressure air knife blowing, which greatly improves the efficiency of aluminum powder removal.

[0040] Based on this, in step S2, a plasma gas flow is used to blow toward the roughened surface of the battery cell to perform a plasma cleaning treatment on the battery cell. The plasma cleaning treatment is set to avoid a small amount of aluminum powder remaining on the surface of the battery cell after the dust removal treatment in step S1, and the plasma surface treatment can also use the plasma gas flow to remove static electricity and gasified residual pollutants on the surface of the battery cell, thereby enhancing the activation energy of the battery cell surface and providing better battery cell surface conditions for the leveling and adhesion of the printed insulation layer.

[0041] In addition, before the plasma cleaning treatment, the battery cells with a roughened surface are subjected to at least one negative pressure dust removal treatment. In general, the simultaneous dust removal during the roughening treatment can achieve the removal of all or most of the aluminum powder, and combined with the plasma cleaning treatment, the surface of the battery cells can be free of pollutants. Based on this, in order to prevent a large amount of aluminum powder or special working conditions, at least one negative pressure dust removal treatment station is set before the plasma cleaning treatment station to ensure that the aluminum powder is completely removed by negative pressure exhaust. In actual applications, the number of negative pressure dust removal treatment stations can be set according to the removal effect. There is no uniform regulation on this number, and the purpose is to completely remove the aluminum powder.

[0042] In addition, during the negative pressure dust removal process, the dust removal nozzle of the negative pressure dust removal equipment is aimed at the roughened surface of the battery cell, and the dust removal nozzle is a flared structure. The negative pressure dust removal process is to remove dust from the entire roughened surface of the battery cell that has been moved into place, which covers a large area, and the amount of aluminum powder is small and scattered. Therefore, the dust removal nozzle is set to a flared structure, which can achieve a large range of aluminum powder extraction to ensure the complete removal of aluminum powder at each position.

[0043] In addition, the aluminum powder produced by the texturing treatment is an explosive substance. During the entire pre-treatment process, explosion-proof equipment is installed on each pipeline to carry out explosion-proof treatment to avoid the explosion of aluminum powder.

[0044] Explosion-proof treatment includes installing flame arresters on each pipeline to prevent the spread of flames.

[0045] And / or, the explosion-proof treatment includes setting a negative pressure gauge and anemometer on the pipeline to detect the pressure and wind speed of the pipeline in real time, and controlling whether to alarm by whether the pressure and wind speed reach the set threshold. For example, when the pressure and wind speed do not reach the set threshold, an alarm is triggered to remind personnel to handle it in time.

[0046] And / or, the explosion-proof treatment includes setting spark detection probes on pipelines and equipment, and controlling whether the fire extinguishing device is activated by detecting sparks by the spark detection probes. For example, when the spark detection probe detects a spark, it can timely feed back a signal to the control system, and the control system will immediately activate the fire extinguishing device to extinguish the spark. The fire extinguishing device can be a common fire extinguisher in the prior art, a perfluorohexanone fire extinguishing device, etc., which can be selected according to the working conditions.

[0047] The explosion-proof settings in the pretreatment process can select one, two or three of the above according to the actual working conditions. Of course, there are many explosion-proof means in the prior art, which are not listed here one by one and can be selected according to the actual working conditions.

[0048] In this way, the pre-treatment process for improving the printing yield of the insulating layer on the surface of the battery cell of the present application adopts a flat-top laser flying roughening treatment combined with synchronous negative pressure dust extraction + at least one negative pressure dust removal treatment + plasma cleaning treatment, which can accurately avoid the empty battery cell pole surface, and the process is simple, pollution-free, and low in energy consumption; the surface of the battery cell can be evenly roughened and the oil, electrolyte, oxide layer and other pollutants on the surface of the battery cell can be completely removed, and the amount of aluminum powder produced is small and avoids damage to the surface of the battery cell, and no tiny burrs will be generated on the surface of the battery cell, thereby improving the efficiency and roughness of the roughening treatment of the surface of the battery cell, and the consistency of the roughness can be ensured, which is conducive to improving the adhesion of the surface of the battery cell; static electricity and gasified residual pollutants on the surface of the battery cell can be removed, thereby enhancing the activation energy of the surface of the battery cell, and providing better surface conditions for the leveling and adhesion of the printed insulating layer. Based on this, the appearance defects such as white spots and pitting on the surface of the battery cell after the printing of the insulating layer can be avoided, and the insulation withstand voltage performance and structural strength of the insulating layer can be improved.

[0049] At the same time, explosion-proof treatment can effectively avoid the risk of aluminum powder explosion to ensure the safety of the entire production line for printing the insulating layer on the surface of the battery cell.

[0050] The technical means disclosed in the present application are not limited to the technical means disclosed in the above-mentioned implementation methods, but also include technical solutions composed of any combination of the above technical features. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of this application, and these improvements and modifications are also regarded as the protection scope of this application.

Claims

1. A pre-treatment process for improving the printing yield of the insulating layer on the surface of a battery cell, characterized in that: The following steps are involved: S1. Use a flat-top laser to roughen the surface of the battery cell and avoid specific areas of the battery cell, and perform dust removal on the surface of the battery cell during the roughening process; S2. Plasma cleaning is performed on the battery cell having the roughened surface.

2. The pre-treatment process for improving the printing yield of the insulating layer on the surface of the battery cell according to claim 1, characterized in that: In the step S1, the texturing treatment adopts a flat-top laser flying process, the laser galvanometer of the laser used to provide the flat-top laser is fixed, the flat-top laser is emitted linearly in a specific direction and with specific energy, and the battery cell moves along a preset path so that its surfaces are texturing treated in turn, and specific areas of the battery cell are avoided.

3. The pre-treatment process for improving the printing yield of the insulating layer on the surface of the battery cell according to claim 2, characterized in that: The specific area includes at least one of the pole of the battery cell, the QR code, the explosion-proof valve, and a blank area surrounding the three.

4. The pre-treatment process for improving the printing yield of the insulating layer on the surface of the battery cell according to claim 2, characterized in that: A visual positioning device is used to identify a specific area of ​​the battery cell and transmit the identification to a control system, so that the control system controls the texturing process to avoid the specific area.

5. The pre-treatment process for improving the printing yield of the insulating layer on the surface of the battery cell according to claim 2, characterized in that: In the step S1, the dust removal process is carried out by means of negative pressure dust extraction, the negative pressure suction nozzle of the dust removal equipment is aimed at the roughened surface of the battery cell, and the negative pressure suction nozzle is flat.

6. The pre-treatment process for improving the printing yield of the insulating layer on the surface of the battery cell according to claim 1, characterized in that: In the step S2, a plasma gas flow is blown toward the roughened surface of the battery cell to perform a plasma cleaning treatment on the battery cell.

7. The pre-treatment process for improving the printing yield of the insulating layer on the surface of the battery cell according to any one of claims 1 to 6, characterized in that: Before the plasma cleaning process is performed, the battery cell with the roughened surface is subjected to at least one negative pressure dust removal process.

8. The pre-treatment process for improving the printing yield of the insulating layer on the surface of the battery cell according to claim 7, characterized in that: During the negative pressure dust removal process, the dust removal nozzle of the negative pressure dust removal equipment is aligned with the roughened surface of the battery cell, and the dust removal nozzle is a flared structure.

9. The pre-treatment process for improving the printing yield of the insulating layer on the surface of the battery cell according to any one of claims 1 to 6, characterized in that: During the entire process of the pre-treatment process, explosion-proof treatment is performed by installing explosion-proof equipment on each pipeline.

10. The pre-treatment process for improving the printing yield of the insulating layer on the surface of the battery cell according to claim 9, characterized in that: The explosion-proof treatment includes providing flame arresters on each pipeline; And / or, the explosion-proof treatment includes setting a negative pressure gauge and anemometer on the pipeline to detect the pressure and wind speed of the pipeline in real time, and controlling whether to alarm by whether the pressure and wind speed reach the set threshold; And / or, the explosion-proof treatment includes setting spark detection probes on pipelines and equipment, and controlling whether the fire extinguishing device is activated based on whether the spark detection probes detect sparks.