Study on Improved VGGNet and SK Convolution Identification Model for Defect Classification of Single Molten Salt Battery

Abstract

Aiming at the lack of large public single molten salt battery data sets, to reduce the labour-consuming, to improve the insufficient learning ability of traditional diagnostic methods in the production of single molten salt battery, an image recognition model for molten salt battery defects based on transfer learning is proposed. First, some pre-processing operations and image enhancement on the single molten salt battery image are performed. Second, the backbone of recognition model is built based on VGG16 network, and the selective kernel (SK) convolution module is adopted after the bottleneck layer, convolution kernel with an appropriate size can be selected adaptively through input feature map; Third, the FC is taken the place of a GAP layer, a dropout layer, and other fine-tuning operations are added, a simplified model called V-VGGNet is got; Finally, the weight parameters obtained from the pre-training on the ImageNet data set are transferred to the single molten salt battery image recognition model V-VGGNet. For different network structures and different training strategies, comparative experiments of performance tests are conducted. The test data manifest that the accuracy rates of V-VGGNet network for three categories of defective images (Missing Negative Electrode, Broken Tab, and Missing Current Collector) and Assembly Normal images can reach 95.14%, 98.79%, 98.21%, and 99.41%, the average accuracy can achieve 97.91%, good performance improvement of the single molten salt battery is improved, it is about 3% higher compared to other well-knows networks, which verified the feasibility of V-VGGNet model and the effectiveness of the improvement.