Dual-surface li-ion battery deformation measurement by temporal electronic speckle pattern interferometry

Abstract

he safety, performance, and lifetime of lithium-ion cells are critical for the acceptance of electric vehicles (EVs), but non-destructively evaluating cell quality issues is not easy. In recent studies, batterie's deformation measurement by optical methods is a promising candidate for detecting a possible local failure originating from mechanical and current inhomogeneities or potential gradients. However, the existing measurement techniques, such as laser scanning and digital image correlation, cannot achieve high-precision deformation measurement up to submicron. In this study, a temporal electronic speckle pattern interferometry (ESPI) is proposed to acquire out-of-plane deformation of both surfaces of a commercial Li-ion polymer battery simultaneously. Various data processing techniques, such as the Fourier and windowed Fourier transform (WFT) methods, are applied in temporal and spatial domains to extract the out-of- displacement during the battery charging process. High-precision deformation of both surfaces can be obtained during the charging process. The result shows that temporal ESPI can be a helpful tool to offer high-precision data for optimizing the Li-ion batteries model.