An understanding of the pulse discharge behavior of commercial lithium coin cells in wireless sensing systems (WSs) is critical to prolonging the operating life and/or reducing the size of such systems. This paper is part of an effort to examine, model and optimize battery performance for sensor duty cycles consisting of multiple pulse discharges. The transient behavior of the cells during pulse discharge and the relaxation behavior following the pulse are both investigated with single-pulse experiments, and described with a simple mathematical model. In both cases, the voltage response is characterized by a region of rapid change, associated with ohmic and interfacial resistances, followed by a region of slower change. Solid phase diffusion in the cathode is the major contributor to the “slow” voltage change that occurs during and after a pulse. A simple analytical model, validated for this system, was found to accurately describe the time-dependent voltage and the corresponding non-uniform concentration distribution for the porous electrode. This transient study provides insight into and a description of the factors that influence and control battery behavior during pulsed cycling, and provides a tool to enable the next generation of battery-aware design of autonomous wireless sensing systems.