The superior energy density and more recent drastic cost reduction have made the Li-ion battery the most promising energy storage technology of the past 20 years. However, several high-profile failures have made the public wary of the potentially dangerous nature of Li-ion batteries. These battery failures – from the ones that grounded the Boeing Dreamliner to the more recent Samsung Galaxy Note 7 – can place consumers in danger as well as require expensive recalls and redesigns. This report presents case studies of previous Li-ion battery failures, quantifying the financial impact to the companies as well as identifying the causes of failure and companies’ responses. It also analyzes the battery components that most affect safety, and finds that separator choice and battery pack design have the largest influence on battery safety.