Study on Thickness Measurement of Diaphragm for Lithium Battery based on Dual Laser Imaging

The accurate and rapid measurement of diaphragm thickness on automatic production line determine its efficiency and quality. In this paper, based on the upper and lower double laser triangulation method used in most of the industrial production lines, a new method called double laser imaging method has been proposed. The structure and working principle of the dual-laser imaging film thickness measurement system were introduced. Then, the influence of the aperture on the measurement system was illustrated by the optical path analysis, and the aberration analysis and evaluation of the optical path were carried out. Finally, the system calibration and data analysis of the dual laser imaging measurement system were given. The experimental results show that the subpixel precision of 1µm can be achieved when the thickness of the diaphragm is less than 50µm, the effectiveness of the system proposed in this paper is validated.