  Safety against thermal failures is crucial in battery systems. Real-time
thermal diagnostics can be a key enabler of such safer batteries. Thermal fault
diagnostics in large format pouch or prismatic cells pose additional challenges
compared to cylindrical cells. These challenges arise from the fact that the
temperature distribution in large format cells is at least two-dimensional in
nature (along length and breadth) while such distribution can be reasonably
approximated in one dimension (along radial direction) in cylindrical cells.
This difference makes the placement of temperature sensor(s) non-trivial and
the design of detection algorithm challenging. In this work, we address these
issues by proposing a framework that (i) optimizes the sensor locations to
improve detectability and isolability of thermal faults, and (ii) designs a
filtering scheme for fault detection and localization based on a
two-dimensional thermal model. The proposed framework is illustrated by
experimental and simulation studies on a commercial battery cell.
