Yongquan Sun 1,2, Lingxi Kong 2, Hassan Abbas Khan 3, and Michael Pecht 2
1 Institute of Sensor and Reliability Engineering (ISRE), Harbin University of Science and Technology, Harbin 150080, China
2 CALCE, Center for Advanced Life Cycle Engineering, Department of Mechanical Engineering, University of Maryland, College Park, Maryland 20740, USA
3 Department of Electrical Engineering, School of Science and Engineering, Lahore University of Management Sciences, Lahore 54792, Pakistan
Abstract:
Li-ion battery reliability has attracted significant research attention, but few studies have
incorporated in-service performance and reliability data of batteries installed within a product. This paper
investigates battery drain, unexpected shutdowns, and slow performance associated with Li-ion batteries,
with a focus on Apple iPhones as a case study. The actions taken by Apple in response to these performance
issues are discussed, especially from the perspective of Li-ion battery degradation. It is shown that not all
battery reliability issues can be attributed to normal battery degradation; battery manufacturing defects and
high C-rate applications are also shown to be contributors to battery reliability and performance issues,
including those causing a low state of charge, a low state of health, and unexpected shutdowns.