The thermal runaway process limits the development and wide application of lithium-ion batteries. More and more researchers are paying attention to how to suppress thermal runaway caused by thermal, electrical, mechanical, and other abuse conditions. Temperature is an important indicator in the process of battery thermal runaway. Using large heat dissipation flow to cool the battery to a safe temperature range can achieve a good thermal runaway suppression effect. This paper discusses the influence of heat dissipation flow on the thermal runaway through combining simulation and experiment. First, a simulation model is established and shows good agreement with the experiment. Both the simulated and experimental results found that an application with a short duration and large heat dissipation flow can achieve a better cooling effect at a suitable battery temperature. Then, we discussed the minimum heat dissipation coefficient required to suppress battery thermal runaway by applying emergency cooling at different battery temperatures. When the trigger temperature rises from 166 °C to 178 °C, the minimum heat dissipation flow required increases from 72 W/m2 to 1391 W/m2. At last, the relationship between trigger temperature and minimum heat dissipation flow was obtained. This provides a reference for emergency cooling of battery thermal runaway.