Mechanical tests are a commonly used method for evaluating the safety performance of batteries. The mechanical blunt rod testing method, as well as sharp nail penetration, was performed on commercially available cells. Evaluation was carried out on different cell constructions as well as varying test conditions. Results obtained at ambient conditions were found to differ little from traditional sharp nail penetration testing. When tested at elevated temperatures it was observed that the results became heavily dependent upon the internal construction of the cell. Computed Tomography (CT) imaging confirmed this, showing differences in behavior depending on whether or not a solid core was used in the cylindrical cell construction. Pouch cells were tested as well, showing that a full penetration of the cell was necessary to initiate a failure event within the cell.