YOLOv7-TDP: A Network on the Defects Detection in Catalyst Coating of PEMFC

Proton exchange membrane fuel cell (PEMFC) is one of the main development directions of new energy and clean power in the future. As the core raw material of hydrogen fuel cell, membrane electrode has engendered ever greater scholarly interest because its performance directly determines the performance and service life of the fuel cell. However, due to the diverse range of defect types, scales, and structural shapes encountered in the production of membrane electrodes for proton exchange membrane catalysts coating, along with the irregular distribution of these defects, achieving rapid and accurate detection poses a significant challenge using existing methods. This limitation adversely impacts cell performance and subsequent processes. A fast detection network based on deformable convolution and disparity-size target detection layer YOLOv7-TDP is proposed for the defects of proton exchange membrane fuel cell catalyst coating. Firstly, the mechanism of coating defects is studied, and a dataset of the defects of proton exchange membrane catalyst coating is constructed, which mainly consists of four main defects, including bubbles, particles, spots, and voids. Secondly, a novel enhanced variable shape feature extraction module is proposed for various defects with irregular distribution, shape and scale. By incorporating deformable convolution, the defect feature extraction network is enhanced to encompass a broader range of defect texture features, which ensures a more comprehensive and inclusive analysis. Finally, a large size target detection layer is added to the model head to increase the detection capability of scale-proportional disparity defects, which better fit the large size defects. The experimental results on the dataset show that the mean accuracy (mAP@IoU=0.5) of the algorithm is 94.1%, which is 8.6% higher than that of the baseline network, and the detection speed is up to 100 fps, which effectively improves the detection accuracy and speed of defects on the surface of catalyst coating.