6533b856fe1ef96bd12b1d92

RESEARCH PRODUCT

Sensitive magnetometry reveals inhomogeneities in charge storage and weak transient internal currents in Li-ion cells

subject

description

The ever-increasing demand for high-capacity rechargeable batteries highlights the need for sensitive and accurate diagnostic technology for determining the state of a cell, for identifying and localizing defects, and for sensing capacity loss mechanisms. Here, we leverage atomic magnetometry to map the weak induced magnetic fields around Li-ion battery cells in a magnetically shielded environment. The ability to rapidly measure cells nondestructively allows testing even commercial cells in their actual operating conditions, as a function of state of charge. These measurements provide maps of the magnetic susceptibility of the cell, which follow trends characteristic for the battery materials under study upon discharge. In particular, hot spots of charge storage are identified. In addition, the measurements reveal the capability to measure transient internal current effects, at a level of μA, which are shown to be dependent upon the state of charge. These effects highlight noncontact battery characterization opportunities. The diagnostic power of this technique could be used for the assessment of cells in research, quality control, or during operation, and could help uncover details of charge storage and failure processes in cells. Fil: Hu, Yinan. Johannes Gutenberg Universitat Mainz; Alemania Fil: Iwata, Geoffrey Z.. Johannes Gutenberg Universitat Mainz; Alemania Fil: Mohammadi, Mohaddese. University of New York; Estados Unidos Fil: Silletta, Emilia Victoria. University of New York; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina Fil: Wickenbrock, Arne. Johannes Gutenberg Universitat Mainz; Alemania Fil: Blanchard, John W.. Helmholtz Institute Mainz; Alemania Fil: Budker, Dmitry. Johannes Gutenberg Universitat Mainz; Alemania Fil: Jerschow, Alexej. University of New York; Estados Unidos