Research And Development Of Lithium-ion Battery Electrode Laser Thickness Measurement Technology And System

Lithium-ion battery electrode coating process is a key process for the manufacture of lithium-ion batteries.The uniformity of the thickness of the coated electrode directly affects the key indicators such as the safety,capacity,and consistency of the lithium-ion battery,so the real-time monitoring and control of the thickness of the electrode is crucial.However,under the conditions of environmental changes and mechanical vibrations,the existing film thickness measurement technology is difficult to meet the demand for high-precision measurement of a lithium ion battery pole piece in a micron range.This article systematically summarizes the current state of the art of thin-film thickness measurement technology for micro-scale high-precision measurement of lithium-ion battery electrode,and addresses the deficiencies of the following research work:In this paper,a variety of thin-film on-line thickness measurement techniques were compared.In combination with the requirements for thickness measurement of the electrode coating,laser thickness measurement was selected as a measurement method.Two different laser thickness measurement methods based on the laser triangulation method were studied in depth.One is a dual-beam single-detector laser thickness measurement.Based on the design and optimization of the ZEMAX optical path,this paper innovatively uses a plano-convex lens and a meniscus lens as the imaging lens group,which improves the imaging accuracy while controlling the cost.Another method is dual laser displacement sensor upper and lower differential thickness measurement.In this paper,a calibration device is added on the basis of conventional differential measurement methods,and a scanning thickness measurement format is designed.After detailed error analysis and comparison of the two thickness measurement methods,the upper and lower differential thickness measurement method of the double laser displacement sensor was selected as the final solution.A thickness measurement control system was designed for the upper and lower differential thickness measurement methods of dual laser displacement sensors.The mechanical design,electrical design,hardware selection,and software system development were completed.The real-time acquisition,processing,display,and storage of electrode thickness data were realized.The experiment was carried out using this laser thickness gage,including static test,dynamic test,air electrode test and coated electrode test.The test results show that the accuracy and stability of the thickness gage can meet the actual thickness measurement of lithium ion battery demand.According to the actual real-time scanning measurement results,the scanning measurement form is improved and the measurement accuracy is guaranteed.