Characterizing Failure Modes and Determining Reliability for Batteries In Medical Device Applications

As medical devices become smaller and more technologically sophisticated, batteries are playing an ever more important role when determining the reliability and safety risk associated with these devices. Unlike the portable consumer electronics industry, where high unit volumes can justify the design and manufacturing of custom batteries, the medical device industry must often utilize standard, off-the-shelf batteries for specialized applications. Even when the production of custom batteries is justified, few battery manufacturers appreciate the level of quality and reliability that is required by the medical device industry.

In this presentation we will explore characterization of failure modes in both primary (non-rechargeable) and secondary (rechargeable) battery systems that may lead to safety and reliability problems. Specifically, we will discuss failure modes associated with improper selection and/or implementation of a battery system for a given application, design and manufacturing defects, and user abuse and/or misuse of the device. Specialized techniques that have been developed to characterize degradation mechanisms and failure modes in batteries, including electrochemical methods, thermal analysis, microscopy, and CT imaging, will be described.

Finally, methods for conducting accelerated aging studies will be discussed. When properly conducted, such aging studies can be used to identify potential reliability issues, monitor the manufacturing quality of the batteries and serve as a tool to aid in the selection and qualification of candidate battery vendors.