Lithium battery electrode plate slitting process capable of reducing slitting damage

Abstract

The invention discloses a lithium battery electrode plate slitting process capable of reducing slitting damage, which is characterized in that a to-be-slit lithium battery electrode plate coiled material is mounted on an unwinding device, and an electrode plate is released through the unwinding device. The released electrode plate passes through the first guide roller group and the pretreatment mechanism in sequence, and the pretreatment mechanism comprises a dust removal unit and a static electricity removal unit which are arranged in sequence. The pretreated electrode plate enters a slitting area, and air injection devices are arranged above and below a slitting blade respectively in the slitting process. And the slit electrode strip and the slitter edge respectively enter the winding mechanism. Tension sensors are arranged at the unwinding end and the winding end, tension is fed back and adjusted in real time, and edge deformation and tearing caused by stretching or loosening of the electrode plates are avoided. The dust removal roller and the ion wind bar are combined to remove surface impurities and static electricity, and abrasion of dust to the blade and material deviation caused by electrostatic adsorption are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium batteries, and particularly to a slitting process for lithium battery electrode sheets that reduces slitting damage. Background Art

[0002] During the production process of lithium batteries, the slitting of electrode sheets is one of the key processes, and the slitting quality directly affects the electrochemical performance and safety of lithium batteries. In the existing slitting process of lithium battery electrode sheets, during the slitting process, problems such as unstable tension control, blade wear, electrostatic adsorption, and debris residue often occur, resulting in damages such as scratches, burrs, and curled edges on the edges of the electrode sheets, which not only affect the dimensional accuracy of the electrode sheets but also may cause safety hazards such as internal short circuits in the batteries.

[0003] In traditional slitting processes, the unwinding and rewinding tensions are mostly mechanically controlled, which is difficult to adjust accurately in real time and easily causes stretching or relaxation of the electrode sheets; there are limitations in the blade angle and surface treatment process of the slitting blades. When cutting at high speed, the blades heat up severely and wear quickly, resulting in uneven cutting edges; in addition, the dust and static electricity on the surface of the electrode sheets will affect the stability of the slitting process. If the debris generated during slitting cannot be removed in time, it is easy to adhere to the surface of the electrode sheets or the blades, further exacerbating the edge damage. Summary of the Invention

[0004] In order to overcome the deficiencies of the prior art solutions, the present invention provides a slitting process for lithium battery electrode sheets that reduces slitting damage, which can effectively solve the problems raised in the background art.

[0005] The technical solution adopted by the present invention to solve its technical problems is as follows:

[0006] A slitting process for lithium battery electrode sheets that reduces slitting damage, comprising the following steps:

[0007] Step S1: Install the coil of the lithium battery electrode sheet to be slit on the unwinding device, release the electrode sheet through the unwinding device, and at the same time, the unwinding device is equipped with a first tension sensor for real-time monitoring of the unwinding tension of the electrode sheet;

[0008] Step S2: The released electrode sheet sequentially passes through the first guide roller group and the pretreatment mechanism. The pretreatment mechanism includes a dust removal unit and an anti-static unit arranged in sequence. The dust removal unit is used to remove the dust on the surface of the electrode sheet, and the anti-static unit is used to eliminate the static electricity on the surface of the electrode sheet;

[0009] Step S3: The preprocessed electrode sheet enters the slitting area, and the slitting device slits the electrode sheet. The slitting device includes a tool shaft and at least two slitting blades. The slitting blades are detachably mounted on the tool shaft. A spacer sleeve is arranged between two adjacent slitting blades. The tool shaft is connected to a driving motor, and the driving motor drives the tool shaft to rotate. The cutting edge angle of the slitting blade is 15°-25°, and the cutting edge surface is coated with a diamond coating;

[0010] Step S4: During the slitting process, air jet devices are respectively arranged above and below the slitting blades. The air jet devices jet inert gas onto the electrode sheet and the slitting blades to cool the slitting blades and blow away the debris generated by slitting;

[0011] Step S5: The slit electrode sheet strips and waste edges respectively enter the winding mechanism. The winding mechanism includes a main winding roller and a waste edge winding roller. The main winding roller is used for winding the slit electrode sheet strips, and the waste edge winding roller is used for winding the waste edges. The main winding roller is equipped with a second tension sensor for real-time monitoring of the winding tension of the electrode sheet strips;

[0012] Step S6: After winding is completed, an appearance inspection is carried out on the wound electrode sheet strips to detect whether there are defects such as damage and burrs at the slitting edges.

[0013] As a further description of the above technical solution, the unwinding device includes an unwinding roller and an unwinding driving mechanism. The unwinding driving mechanism is connected to the unwinding roller and is used for driving the unwinding roller to rotate. The first tension sensor is arranged on the electrode sheet path between the unwinding roller and the first guide roller group.

[0014] As a further description of the above technical solution, the dust removal unit includes at least two dust removal rollers. The surface of the dust removal rollers is wrapped with dust removal cloth. The dust removal cloth contacts the surface of the electrode sheet and is used for wiping the dust on the surface of the electrode sheet.

[0015] As a further description of the above technical solution, the static elimination unit is an ion air bar. The ion air bar is arranged behind the dust removal unit and is used for jetting ion wind onto the surface of the electrode sheet to eliminate static electricity.

[0016] As a further description of the above technical solution, the cutting edge angle of the slitting blade is 20°, and the thickness of the diamond coating is 5-10 microns.

[0017] As a further description of the above technical solution, the air jet device includes an air pump and an air jet nozzle. The air jet nozzle faces the slitting blade and the electrode sheet, and the air pump provides inert gas with a pressure of 0.3-0.5 MPa.

[0018] As a further description of the above technical solution, both the main winding roller and the waste edge winding roller are connected with winding drive mechanisms, and the winding drive mechanisms adjust the winding speed according to the feedback signal of the second tension sensor to keep the winding tension stable.

[0019] As a further description of the above technical solution, the appearance detection is carried out by a vision detection system, and the vision detection system includes a camera and an image processing unit. The camera captures the edge image of the slit electrode sheet, and the image processing unit analyzes the image to judge whether there is damage.

[0020] As a further description of the above technical solution, guide rollers are arranged in front of and behind the slitting device, and the guide rollers are used to guide the running direction of the electrode sheet to ensure that the electrode sheet remains flat during the slitting process.

[0021] As a further description of the above technical solution, the surface of the guide roller is provided with an anti-slip coating, and the anti-slip coating is made of rubber material, which is used to increase the friction between the electrode sheet and the guide roller and prevent the electrode sheet from slipping.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] A lithium battery electrode sheet slitting process for reducing slitting damage of the present invention has at least one of the following beneficial effects during use:

[0024] Tension sensors are arranged at the unwinding and winding ends to feedback and adjust the tension in real time, avoiding edge deformation and tearing of the electrode sheet caused by stretching or relaxation, ensuring uniform stress on the material during the slitting process, and improving the dimensional accuracy. The combination of the dust removal roller and the ion air bar removes surface impurities and static electricity, reduces the wear of the blade by dust and the material deviation caused by static electricity adsorption, provides a clean and stable base material for slitting, and reduces the risk of edge scratches caused by debris residue. The blade angle is optimized to 15°-25° and coated with a diamond coating to enhance the sharpness and wear resistance of the blade. Combined with inert gas cooling and chip blowing, it reduces the influence of cutting heat and blade clogging, makes the slitting edge smooth and burr-free, and reduces the blade replacement frequency. The winding drive mechanism dynamically adjusts the speed according to the tension feedback to avoid stress concentration during winding; the vision detection system captures the edge image in real time, accurately identifies damage defects, and realizes the closed-loop control of the slitting quality. Guide rollers with anti-slip coatings are arranged before and after the slitting device to ensure the flat conveying of the electrode sheet, prevent deviation or slipping, guarantee the slitting position accuracy from the mechanical structure, and comprehensively improve the yield and production efficiency. Description of the Drawings

[0025] Figure 1 It is a process flow chart of a lithium battery electrode sheet slitting process for reducing slitting damage of the present invention. Detailed Embodiments

[0026] Next, in combination with the accompanying drawings in the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0027] As Figure 1 shown, the present invention provides a lithium battery electrode sheet slitting process for reducing slitting damage, including the following steps:

[0028] Step S1: Install the lithium battery electrode sheet coil to be slit on the unwinding device, release the electrode sheet through the unwinding device, and at the same time, the unwinding device is equipped with a first tension sensor for real-time monitoring of the unwinding tension of the electrode sheet;

[0029] The first tension sensor real-time collects the tension data during the unwinding process of the electrode sheet, and dynamically adjusts the rotation speed of the unwinding drive mechanism through the feedback control system to keep the unwinding tension at a set threshold (such as 5 - 10 N / mm 2 ). When the tension fluctuates due to the decrease in the coil diameter, the sensor signal drives the unwinding roller to accelerate or decelerate to prevent the electrode sheet from being stretched due to excessive tension or becoming slack due to too small tension.

[0030] Step S2: The released electrode sheet sequentially passes through the first guide roller group and the pretreatment mechanism. The pretreatment mechanism includes a dust removal unit and an electrostatic elimination unit arranged in sequence. The dust removal unit is used to remove the dust on the surface of the electrode sheet, and the electrostatic elimination unit is used to eliminate the static electricity on the surface of the electrode sheet;

[0031] Step S3: The pretreated electrode sheet enters the slitting area, and the slitting device slits the electrode sheet. The slitting device includes a cutter shaft and at least two slitting blades. The slitting blades are detachably installed on the cutter shaft, and a spacer sleeve is arranged between adjacent two slitting blades. The cutter shaft is connected with a driving motor, the driving motor drives the cutter shaft to rotate, and the cutting edge angle of the slitting blade is 15° - 25°, and the cutting edge surface is coated with a diamond coating;

[0032] The main winding roller and the waste edge winding roller are controlled by independent driving motors (such as servo motors). Based on the real-time data of the second tension sensor, the rotation speed ratio (such as 1:0.95 - 1.05) is dynamically adjusted by using the PID algorithm to make the waste edge winding speed match the main winding speed and avoid the deformation of the edge of the main electrode sheet strip caused by the pulling of the waste edge.

[0033] Step S4: During the slitting process, jetting devices are respectively arranged above and below the slitting blades. The jetting devices jet inert gas to the electrode sheet and the slitting blades to cool the slitting blades and blow away the debris generated by slitting;

[0034] The air pump supplies nitrogen or argon gas with a pressure of 0.3 - 0.5 MPa, which is sprayed onto the blade cutting area through the air nozzle at a speed of 30 - 50 m / s. On the one hand, the high-speed air flow takes away the heat generated during cutting (the temperature reduction range can reach 50 - 80 °C), avoiding the melting of the coating on the edge of the electrode sheet caused by local high temperature; on the other hand, it blows away the cutting debris (such as metal foil scraps and coating peeling particles), preventing the accumulation of debris from causing blade blockage or secondary scratching.

[0035] Step S5: The slit electrode sheet strips and the waste edges respectively enter the winding mechanism. The winding mechanism includes a main winding roller and a waste edge winding roller. The main winding roller is used to wind the slit electrode sheet strips, and the waste edge winding roller is used to wind the waste edges. And the main winding roller is equipped with a second tension sensor for real-time monitoring of the winding tension of the electrode sheet strips;

[0036] The second tension sensor monitors the winding tension of the main winding roller, and the winding drive mechanism synchronously adjusts the winding speed according to the feedback signal to ensure that the slit electrode sheet strips are evenly stressed during the winding process. For example, when a sudden increase in tension is detected, the drive mechanism automatically reduces the winding speed to prevent tearing caused by stress concentration at the edge.

[0037] Step S6: After winding is completed, the wound electrode sheet strips are subjected to appearance inspection to detect whether there are defects such as damage and burrs at the slitting edges.

[0038] At least two dust removal rollers are in elastic contact with the surface of the electrode sheet. The wrapped dust removal cloth (such as fiber fabric) uses the friction adsorption principle to remove dust particles on the surface. The roller bodies can be designed to rotate towards each other to improve the cleaning efficiency by double-sided wiping, avoiding dust particles from embedding in the blade or scratching the electrode sheet during slitting.

[0039] The ion wind bar generates positive and negative ion flows to neutralize the static electric charges accumulated on the surface of the electrode sheet (for example, the static voltage generated by friction during the production process can reach several thousand volts). The ion wind is directed to spray onto the surface of the electrode sheet, reducing the static electric field strength to a safe threshold (<100 V) and eliminating problems such as material offset or debris adhesion caused by static adsorption.

[0040] Furthermore, the unwinding device includes an unwinding roller and an unwinding drive mechanism. The unwinding drive mechanism is connected to the unwinding roller and is used to drive the unwinding roller to rotate. The first tension sensor is arranged on the electrode sheet path between the unwinding roller and the first guiding roller group.

[0041] The slitting blade uses a blade angle of 15° - 25° (preferably 20°), which balances the cutting resistance and the blade strength, making the fracture surface of the material more flat during the cutting process. The diamond coating (with a thickness of 5 - 10 μm) is formed by chemical vapor deposition (CVD) process. Its hardness (HV≥8000) is significantly higher than that of the traditional tungsten carbide coating, which can reduce the cutting friction coefficient by 30% - 50% and reduce the adhesion between the blade and the electrode sheet coating (such as the active material layer).

[0042] Furthermore, the dust removal unit includes at least two dust removal rollers, and the surface of the dust removal rollers is wrapped with dust removal cloth, which contacts the surface of the electrode sheet and is used to wipe the dust on the surface of the electrode sheet.

[0043] The main winding roller and the waste edge winding roller are controlled by independent drive motors (such as servo motors). Based on the real-time data of the second tension sensor, the rotation speed ratio (such as 1:0.95 - 1.05) is dynamically adjusted by the PID algorithm to make the waste edge winding speed match the main winding speed, avoiding the deformation of the edge of the main electrode sheet strip caused by the pulling of the waste edge.

[0044] Furthermore, the static elimination unit is an ion air bar, which is arranged behind the dust removal unit and is used to spray ion wind onto the surface of the electrode sheet to eliminate static electricity.

[0045] Furthermore, the blade angle of the slitting blade is 20°, and the thickness of the diamond coating is 5 - 10 microns.

[0046] The air jet device realizes self-cleaning of the blade, reducing the frequency of manual downtime for blade cleaning (from once per hour to once every 4 hours), and the daily production capacity of a single production line is increased by more than 20%. The coordinated control of the tension sensor and the winding drive mechanism avoids the tape breakage accident caused by sudden tension change (the incidence rate decreases by 70%), reducing material waste and equipment loss.

[0047] Furthermore, the air jet device includes an air pump and an air jet nozzle. The air jet nozzle faces the slitting blade and the electrode sheet, and the air pump provides an inert gas with a pressure of 0.3 - 0.5 MPa.

[0048] The vision inspection system realizes 100% full inspection, and the defect recognition accuracy rate > 99%. Combining dust removal and static elimination in the pretreatment link, a quality control system is constructed from the source to the end. This process is suitable for slitting electrode sheets with different thicknesses (50 - 200 μm), especially for the protection of extremely thin coatings (such as ceramic coatings < 10 μm), broadening the process application scope of lithium battery production.

[0049] Furthermore, both the main winding roller and the waste edge winding roller are connected with winding drive mechanisms, and the winding drive mechanisms adjust the winding speed according to the feedback signal of the second tension sensor to keep the winding tension stable.

[0050] Through closed-loop tension control (unwinding / winding tension fluctuation ≤ 5%), blade performance optimization (lifespan increased by more than 2 times), and inert gas protection, the incidence rate of burrs on the slitting edge is reduced from 15% - 20% of the traditional process to less than 3%, and defects such as notches and curled edges are reduced by 80%, meeting the stringent requirements of high-end lithium batteries for the edge roughness of the electrode sheet (Ra ≤ 10μm).

[0051] Further, the appearance inspection is carried out through a vision inspection system. The vision inspection system includes a camera and an image processing unit. The camera captures the edge image of the slit electrode sheet, and the image processing unit analyzes the image to determine whether there are damages.

[0052] The anti-slip design of the guide rollers and the pre-treatment cleaning process enable the running offset of the electrode sheet to be ≤ ±0.3mm, and the slitting width tolerance is controlled within ±0.1mm, significantly superior to the industry standard (±0.5mm). The diamond-coated blade is combined with a precise blade angle to avoid the problem of gradual change in slitting width caused by blade wear, and the fluctuation of the slitting accuracy between batches is < 0.5%.

[0053] Further, guide rollers are arranged both in front of and behind the slitting device. The guide rollers are used to guide the running direction of the electrode sheet to ensure that the electrode sheet remains flat during the slitting process.

[0054] Further, the surface of the guide roller is provided with an anti-slip coating. The anti-slip coating is made of rubber and is used to increase the friction between the electrode sheet and the guide roller to prevent the electrode sheet from slipping.

[0055] The guide rollers before and after the slitting device adopt a rubber anti-slip coating (friction coefficient ≥ 0.6), contact with the electrode sheet through the roller surface pressure (0.2 - 0.5N / mm), and use the friction force to restrain the lateral offset of the material (accuracy ≤ ±0.1mm). The spacing and height of the roller group can be finely adjusted to ensure that the electrode sheet remains flat and taut before entering the slitting area.

[0056] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, in any aspect, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be encompassed by the present invention. Any reference signs in the claims should not be regarded as limiting the claimed rights.

Claims

1. A slitting process for lithium battery electrode sheets to reduce slitting damage, characterized in that: It includes the following steps: Step S1: Install the lithium battery electrode sheet coil to be slit on the unwinding device, release the electrode sheet through the unwinding device, and at the same time, the unwinding device is equipped with a first tension sensor for real-time monitoring of the unwinding tension of the electrode sheet; Step S2: The released electrode sheet sequentially passes through the first guiding roller group and the pretreatment mechanism. The pretreatment mechanism includes a dust removal unit and an anti-static unit arranged in sequence. The dust removal unit is used to remove the dust on the surface of the electrode sheet, and the anti-static unit is used to eliminate the static electricity on the surface of the electrode sheet; Step S3: The pretreated electrode sheet enters the slitting area, and the slitting device slits the electrode sheet. The slitting device includes a cutter shaft and at least two slitting blades. The slitting blades are detachably installed on the cutter shaft, and a spacer sleeve is arranged between adjacent two slitting blades. The cutter shaft is connected with a driving motor, and the driving motor drives the cutter shaft to rotate. And the cutting edge angle of the slitting blade is 15°-25°, and the cutting edge surface is coated with a diamond coating; Step S4: During the slitting process, jetting devices are respectively arranged above and below the slitting blades. The jetting devices jet inert gas to the electrode sheet and the slitting blades to cool the slitting blades and blow away the chips generated by slitting; Step S5: The slit electrode sheet strips and the waste edges respectively enter the winding mechanism. The winding mechanism includes a main winding roller and a waste edge winding roller. The main winding roller is used for winding the slit electrode sheet strips, and the waste edge winding roller is used for winding the waste edges. And the main winding roller is equipped with a second tension sensor for real-time monitoring of the winding tension of the electrode sheet strips; Step S6: After winding is completed, perform an appearance inspection on the wound electrode sheet strips to detect whether there are defects such as damage and burrs at the slitting edges.

2. The slitting process of a lithium battery electrode sheet for reducing slitting damage according to claim 1, characterized in that: The unwinding device includes an unwinding roller and an unwinding driving mechanism. The unwinding driving mechanism is connected with the unwinding roller and is used to drive the unwinding roller to rotate. The first tension sensor is arranged on the electrode sheet path between the unwinding roller and the first guiding roller group.

3. A lithium battery electrode sheet slitting process for reducing slitting damage according to claim 1, characterized in that: The dust removal unit includes at least two dust removal rollers. The surfaces of the dust removal rollers are wrapped with dust removal cloths. The dust removal cloths are in contact with the surface of the electrode sheet and are used to wipe the dust on the surface of the electrode sheet.

4. A slitting process for a lithium battery electrode sheet to reduce slitting damage according to claim 1, characterized in that: The anti-static unit is an ion air bar. The ion air bar is arranged behind the dust removal unit and is used to jet ion wind to the surface of the electrode sheet to eliminate static electricity.

5. A lithium battery electrode sheet slitting process for reducing slitting damage according to claim 1, characterized in that: The cutting edge angle of the slitting blade is 20°, and the thickness of the diamond coating is 5-10 microns.

6. A slitting process for a lithium battery electrode sheet to reduce slitting damage according to claim 1, characterized in that: The jetting device includes an air pump and a jetting nozzle. The jetting nozzle faces the slitting blades and the electrode sheet. The air pump provides inert gas with a pressure of 0.3-0.5 MPa.

7. A lithium battery electrode sheet slitting process for reducing slitting damage according to claim 1, characterized in that: Both the main winding roller and the waste edge winding roller are connected with winding driving mechanisms. The winding driving mechanisms adjust the winding speed according to the feedback signal of the second tension sensor to keep the winding tension stable.

8. A slitting process for a lithium battery electrode sheet to reduce slitting damage, characterized in that: The appearance inspection is carried out through a vision inspection system. The vision inspection system includes a camera and an image processing unit. The camera takes images of the edges of the slit electrode sheet, and the image processing unit analyzes the images to judge whether there is damage.

9. A slitting process for a lithium battery electrode sheet to reduce slitting damage according to any one of claims 1-8, characterized in that: Guide rollers are provided both in front of and behind the slitting device. The guide rollers are used to guide the running direction of the electrode sheet to ensure that the electrode sheet remains flat during the slitting process.

10. A lithium battery electrode sheet slitting process for reducing slitting damage according to claim 9, characterized in that: An anti-slip coating is provided on the surface of the guide roller. The anti-slip coating is made of rubber and is used to increase the friction between the electrode sheet and the guide roller to prevent the electrode sheet from slipping.

Images