Steve Harris (LBNL): "In-situ x-ray battery property spatiotemporal mapping"

Wednesday 27 Mar 2019, 12:00 → 13:00 US/Pacific

Auditorium (050)

Abstract:

There are relatively few publications that assess capacity decline in enough nominally identical commercial cells to quantify cell-to-cell variability, but those that do show that variability is surprisingly large. Capacity curves cross each other often, a challenge for efforts to measure the state of health and predict the remaining useful life (RUL) of individual cells. We will provide a quantitative analysis of variability showing that spatial heterogeneity in cells, universally ignored in failure analysis, is important, and we show a new way to predict RUL. We then present a new experimental approach that provides operando through-thickness measurements inside unmodified commercial prismatic Li-ion cells. Failure analysis of commercial cells is critical because the lives of lab-made cells are often at least an order of magnitude shorter than the lives of analogous commercial cells, suggesting that they have different failure modes. Our approach, which has a sub-mm in-plane spatial resolution, simultaneously provides local, real-time internal temperature maps of both electrodes; local, real-time internal state-of-charge maps of both electrodes; and local, real-time maps of the binding strength of both electrodes to their respective current collectors—all without embedding any intrusive sensors that may alter battery behavior.

about_the_speaker.pdf