In operando thermal signature probe for lithium-ion batteries

Thermal metastability is an inescapable trait of lithium-ion batteries. However, canonically, only electrochemical signatures are studied as calorimetry imposes a controlled environment to isolate the self-heating signal. We propose an in operando approach for characterizing the thermal signatures. Using an inverse heat transfer formulation, we deconvolve the self-heating signature from other simultaneous heat transfer modes. Temporal variation of heat generation is subsequently estimated. This approach does not presuppose a particular electrochemical operation and is agnostic to materials used in the Li-ion cells. The generality and simplicity of this experimental approach rely on inverse thermal analysis and concurrent calibration of ambient natural convection response.