Understanding the mechanical, thermal, and electrical properties of prismatic lithium-ion batteries (LIBs) is vital to battery safety design, which is key to electric vehicle safety. This study investigated prismatic LIBs subjected to multiple-position indentation loading. The side face of an intact prismatic LIB cell is divided into 15 compressed sections. Experimental results indicate that indentation loading of all sections could initiate thermal runaway. Among the sections studied, that near the positive terminal shows the highest risk of thermal runaway, whereas that near the top-right corner is relatively safe. Failure mode analysis reveals that short circuits may result from contact between the positive and negative current collectors.