Material parameter analysis of lithium-ion battery based on laboratory X-ray computed tomography

Accurate analysis of electrode material parameters is of great significance for advancing Lithium-ion battery research. This paper presents the first application of the laboratory X-ray computed tomography (CT) technique for the material parameter analysis of rectangular lithium iron phosphate (LFP) battery. Firstly, performing a disassembly experiment of rectangular LFP battery, the geometric size of positive and negative electrodes and the heterogeneity of materials are analyzed. Secondly, a sine function model is proposed to identify the 2D tomographic images representing the positive and negative electrodes from the reconstructed 3D dataset. Then, the histograms of the 2D tomographic images are fitted with a Gaussian function to identify and quantify the content of electrode materials. Finally, the distributions of positive and negative materials are quantified by meshing and contour plots. The positive and negative materials are unevenly distributed on current collectors, and their distribution properties are closely related to the distance between the electrodes and the thickness center of the wound prismatic cell. The locations of the low aggregation regions of the positive and negative materials are not consistent. It can be expected that this paper will provide a new insight into the analysis of 3D imaging of electrode materials before/after battery operation.