In the pursuit of enhancing lithium-ion battery safety, a novel strategy involves the integration of a potentioresistive polymer layer between the positive electrode and the current collector. Under normal conditions, this protective layer exhibits high conductivity, minimally affecting battery performance. However, upon heating, too high or too low cell voltage application, it transits to a high-resistance state, significantly limiting current flow. This study focuses on the electrochemical processes occurring in a lithium-ion battery, both with and without the protective layer, when subjected to an internal short circuit caused by nail penetration. The protective layer is assumed to instantaneously switch to its non-conductive state. When solving the problem using the finite element method, the modeling technique was enhanced to improve convergence and accelerate solution speed. The calculation results enabled us to identify battery discharge fronts. A battery without a protective layer discharges rapidly throughout its entire volume, whereas a battery with a protective layer discharges quickly only in the area adjacent to the nail, with slower discharge occurring in the remaining regions. This investigation highlights the potential of potentioresistive polymers in advancing lithium-ion battery safety.