First Imaging Experiment of a Lithium Ion Battery by a Pulsed Neutron Beam at J-PARC/MLF/BL09

We obtain the transmission image of a commercial lithium ion (Li-ion) battery using a pulsed neutron beam at the beamline 09 of the Materials and Life Science Experimental Facility at the Japan Proton Accelerator Research Complex. The purpose of this study is to improve the performance of the Li-ion battery by nondestructive observation of its charging and discharging. The transmission images for three charge states (3.2 V, 3.7 V, and 4.2 V) reveal differences between these three states, which we attribute to electrolyte migration. The transmission spectra show Bragg edges originating from the electrodes, current collectors, and battery vessel. Although the battery as a whole has the expected relation between the charge accumulation and the quantity of lithium amounts in the positive and negative electrodes, a portion of the battery deviates from this relation, which may imply a position dependent charging in the battery.