The performance and thermal response of large-scale GS-Yuasa LEV50 50-Ah NMC automotive battery cells were investigated via simulation. To evaluate local transient temperature distributions, the Dualfoil model was coupled to local energy-balance equations. At similar C rates the difference between maximum and minimum temperature in the LEV50 was found to be higher than that in an 18650 cell with identical chemistry. Unlike thinner prismatic lithium ion batteries, the temperature variation through the cell thickness in the large-format cell was not negligible (∼5 °C at 4C discharge). Because of the non-uniform temperature distribution within the jellyroll, the risk of lithium plating at high charging rates and low ambient temperatures may be greater toward the jellyroll exterior. Simulations of thermal abuse (oven test) of the large cell showed a delayed thermal response relative to the 18650, but also indicated a lower onset temperature for thermal runaway.