Nick Williard, Wei He, Dr. Michael Osterman, Professor. Michael Pecht
Center for Advanced Life Cycle Engineering (CALCE), Room llO3, Eng. Lab Bldg 89
University of Maryland College Park, MD 20742
This paper presents an investigation into the reliability and physical degradation mechanisms associated with the loss of battery performance. Cells from two different manufactures underwent cycle life testing until failure (defined as a 20% decrease in nominal capacity). Designated samples from each battery type were subjected to one of two different discharge methods one at a constant discharge rate of 1 C and the other at a con;tant discharge rate of O.5C. A third group of batteries were collected and examined after undergoing catastrophic failure in field applications. The tape pull test (to test adhesion/cohesion of electrode material to current collectors) is introduced for the first time in battery literature. Other analysis techniques such as x-ray imaging and environmental scanning electron microscopy were used to investigate the structural and chemical degradation of all the samples. Statistical analysis was performed on the cycle life data to evaluate battery reliability.
Complete article available from the publisher and to CALCE Consortium Members.