Optimization of Excitation Coil Parameters for PECT of Defects in Laser Welding of Power Battery Pack Based on Kriging Surrogate Model

Pulse eddy current testing (PECT) technology is an effective means to achieve the defect detection for laser welding structure of power battery pack. In order to ensure the sensitivity and accuracy of PECT for power battery pack welding structure, a method of optimizing the structural parameters of the excitation coil of the PECT is proposed based on the kriging surrogate model. A finite element simulation model is established for PECT of the laser welding structure of the power battery pack. The peak value of the differential induced voltage as response values are calculated under the initial sample points obtained by symmetric latin hypercube design (SLHD). The kriging surrogate model is established to characterize the coupling relationship between the initial samples and the response values. The error of the response values of the objective function is selected as the convergence condition, and the efficient global optimization (EGO) algorithm is used to update the surrogate model. The optimal parameters are outputted when the surrogate model meets the convergence conditions. By conducting comparison between simulation and experiment, the response values of the detected signal optimized by the kriging surrogate model is 67.2% higher than that of the single‐factor optimization method. The kriging surrogate model optimization method can effectively improve the sensitivity of the PECT system for laser welding defect of power battery pack.