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CN-122025557-A - Surface treatment method and online treatment system for lithium ion battery pole piece

CN122025557ACN 122025557 ACN122025557 ACN 122025557ACN-122025557-A

Abstract

The invention belongs to the technical field of lithium ion battery manufacturing, and particularly discloses a surface treatment method and an online treatment system for a lithium ion battery pole piece. The method comprises the steps of sequentially applying UV pretreatment, high-frequency high-voltage electric field treatment and UV deep optimization treatment after a pole piece finishes a coating process and before the pole piece enters a rolling process and/or after the pole piece finishes the rolling process and before the pole piece enters the next process, wherein the UV pretreatment adopts 185-254nm ultraviolet light, irradiance is 10-2000 mW/cm < 2 >, the output voltage of the high-frequency high-voltage electric field treatment is 1-200kV, frequency is 1-100kHz, power is 1-100kW, UV deep optimization adopts 222-395nm ultraviolet light, and irradiance is 10-2000 mW/cm < 2 >. The invention can efficiently remove pollutants on the surface of the pole piece, accurately regulate and control the surface roughness, relieve the difference of compaction density between the surface and the interior, and improve the interface binding force and the battery performance. The invention can be widely applied to the manufacture of lithium ion battery pole pieces.

Inventors

  • MIAO JIANJUN
  • SHEN TIANNA
  • ZHOU LISEN

Assignees

  • 般若涅利（北京）装备技术有限公司

Dates

Publication Date
20260512
Application Date
20260309

Claims (10)

  1. 1. The surface treatment method of the lithium ion battery pole piece is characterized in that according to the process requirements, the following steps can be sequentially carried out after the pole piece finishes the coating process and before entering the rolling process, and/or after the pole piece finishes the rolling process and before entering the next process: S1, carrying out UV pretreatment on the surface of a polar plate, wherein the UV pretreatment adopts ultraviolet light irradiation with the wavelength of 185-254 nm, and the irradiance is 10-2000 mW/cm < 2 >; s2, carrying out high-frequency high-voltage electric field treatment on the surface of the pole piece, wherein the output voltage of the high-frequency high-voltage electric field treatment is 1-200 kV, the frequency is 1-100 kHz, and the output power is 1-100 kW; S3, carrying out UV depth optimization treatment on the surface of the pole piece, wherein the UV depth optimization treatment adopts ultraviolet light irradiation with the wavelength of 222-395 nm, and irradiance is 10-2000 mW/cm < 2 >.
  2. 2. The method for treating the surface of a lithium ion battery pole piece according to claim 1, wherein in the high-frequency high-voltage electric field treatment in the step S2, a carrier gas is used which is at least one of helium, nitrogen and argon, and oxygen with a volume ratio of 1% -95% is mixed in the carrier gas, and the distance between the pole piece and the high-frequency high-voltage electric field generating electrode is 1-15 mm.
  3. 3. The surface treatment method of a lithium ion battery pole piece according to claim 1 or 2, wherein the treatment speeds of the steps S1, S2 and S3 are kept synchronous and are 1-200 m/min.
  4. 4. An online processing system for realizing the surface treatment method of the lithium ion battery pole piece according to any one of claims 1-3, which is characterized in that a first processing unit is arranged in front of a roller press, and a second processing unit is arranged behind the roller press; The first processing unit and the second processing unit comprise a first UV light irradiation module, a high-frequency high-voltage electric field generation module and a second UV light irradiation module which are sequentially arranged along the transmission direction of the pole piece; The first UV light irradiation module is used for executing the UV pretreatment; the high-frequency high-voltage electric field generating module is used for executing the high-frequency high-voltage electric field treatment and comprises an electrode assembly and a mixed gas input assembly connected with the electrode assembly; the second UV light irradiation module is used for performing the UV depth optimized combing.
  5. 5. The on-line processing system of claim 4, further comprising a gas protection module disposed at the pole piece inlet and the pole piece outlet of the first processing unit and also disposed at the pole piece inlet and the pole piece outlet of the second processing unit.
  6. 6. The on-line processing system according to claim 4, further comprising an on-line monitoring module, wherein the on-line monitoring module is disposed at a last part of the processing flow of the first processing unit and the second processing unit, and comprises a surface roughness sensor and a visual inspection camera for acquiring the surface quality data of the pole piece in real time.
  7. 7. An in-line processing system according to any one of claims 4 to 6, wherein the first and second UV light irradiation modules are each capable of independently adjusting irradiation parameters and are provided with a protectable optical window.
  8. 8. An in-line processing system according to any one of claims 4 to 6, wherein the electrode assembly of the high frequency high voltage electric field generating module is a multi-nozzle array, and each nozzle is capable of independently adjusting its output power and gas ratio.
  9. 9. An in-line processing system according to any one of claims 4 to 6, wherein the first UV light irradiation module, the high frequency high voltage electric field generating module and the second UV light irradiation module are capable of being activated by any single module, by any two modules in cooperation or by three modules in cooperation.
  10. 10. An in-line processing system according to any one of claims 4 to 6, wherein at least one of the first UV light irradiation module, the high-frequency high-voltage electric field generating module and the second UV light irradiation module is of a modular design, and can be expanded by increasing the number of sub-modules; the extension includes: Multiple groups of submodules with the same function are connected in series along the transmission direction of the pole piece so as to enhance the processing intensity or speed; Multiple groups of submodules with the same function are stacked side by side in the width direction perpendicular to the pole piece transmission direction so as to adapt to pole pieces with different widths.

Description

Surface treatment method and online treatment system for lithium ion battery pole piece Technical Field The invention belongs to the technical field of lithium ion battery manufacturing, and particularly relates to a surface treatment method and an online treatment system for a lithium ion battery pole piece. Background In the manufacturing process of the lithium ion battery pole piece, the rolling process is a key step for improving the compacted density of the coating and enhancing the binding force of the active substance and the current collector. However, the existing rolling process has the following technical defects that 1, the solvent, binder concentrate and environmental dust which are not completely volatilized are easy to remain on the surface of a pole piece in a coating process, the impurities are pressed into the coating in the rolling process to form intractable pollution points, and the consistency and the cycle life of a battery are affected, 2, surface mechanical damage and metal burrs are that high-pressure contact of a metal roller and active particles during rolling are easy to cause particle breakage and coating microcrack, burrs can be generated on the edge of a metal foil, and the tiny metal chips can puncture a diaphragm in a later process to cause micro short circuit and even thermal runaway, 3, the surface layer and the inner density are inconsistent, the surface layer and the inner density are excessively compacted to form a high-density compact layer on the surface layer of the pole piece, and the inner density is relatively low, the density gradient prevents lithium ions from being rapidly embedded/separated, the internal resistance of the battery is increased, and the multiplying power performance is reduced. In the prior art, the surface treatment technology comprises the steps of mechanically brushing off a vulnerable coating and generating secondary dust, simple ultraviolet photolysis is effective on organic pollutants, but has weak capability of removing inorganic microparticles and metal fragments, and although the surface can be etched by single plasma treatment, the surface can be difficult to finely control and can be excessively etched. No technology can simultaneously meet the requirements of efficient impurity removal, microstructure regulation and control, density homogenization and online adaptation for high-speed production. Therefore, it is necessary to develop a non-contact, efficient and controllable pole piece surface cooperative treatment method, which integrates multiple functions of cleaning, modification and structure regulation, so as to overcome the technical bottleneck. ‌ ‌ A Disclosure of Invention The invention aims to provide a surface treatment method for a lithium ion battery pole piece, which can efficiently remove organic pollutants, inorganic pollutants, metal burrs and broken particles on the surface of the pole piece, accurately regulate and control the surface roughness, relieve the difference of compaction density between the surface and the interior, and improve the interface binding force and the battery performance; The second object of the invention is to provide an online processing system for realizing the method, which can be compatible with continuous operation of various materials, and is efficient and environment-friendly. The technical scheme adopted by the invention for realizing the purposes is as follows: The surface treatment method of the lithium ion battery pole piece comprises the following steps of, after the pole piece finishes the coating process, before entering the rolling process, and/or after the pole piece finishes the rolling process, before entering the next process: S1, carrying out UV pretreatment on the surface of a polar plate, wherein the UV pretreatment adopts ultraviolet light irradiation with the wavelength of 185-254 nm, and the irradiance is 10-2000 mW/cm < 2 >; s2, carrying out high-frequency high-voltage electric field treatment on the surface of the pole piece, wherein the output voltage of the high-frequency high-voltage electric field treatment is 1-200 kV, the frequency is 1-100 kHz, and the output power is 1-100 kW; S3, carrying out UV depth optimization treatment on the surface of the pole piece, wherein the UV depth optimization treatment adopts ultraviolet light irradiation with the wavelength of 222-395 nm, and irradiance is 10-2000 mW/cm < 2 >. In the high-frequency high-voltage electric field treatment of the step S2, the carrier gas is at least one of helium, nitrogen and argon, and oxygen with the volume ratio of 1-95% is mixed in the carrier gas, and the distance between the pole piece and the high-frequency high-voltage electric field generating electrode is 1-15 mm. As a second limitation, the processing speeds of steps S1, S2 and S3 are kept synchronous, and are 1-200 m/min. An online processing system is used for realizing the surface processing method of the lithium ion battery pol