Our Principal Electrical Engineer, Lucas Sturnfield, wrote an article for Medical Device and Diagnostic Industry (MD+DI) in October 2017 that describes design approaches for protecting patients from thermal runaway in large lithium-ion batteries.
Lithium-ion technologies are widely adopted into medical devices due to their best-in-class energy density (250-700 Wh/L) and specific power (250-330 W/kg). The ability to fit substantial amounts of energy into a small volume, and having the energy storage mechanism weigh relatively little, is extremely compelling for medical systems which enable patient mobility.
Lithium-ion cell manufacturers, battery pack integrators, and medical systems designers work very hard to maximize the utility of these lithium-ion technologies. Cell manufacturers develop and launch higher-capacity and higher-power cells every year. Battery integrators leverage the cell technology improvements to develop solutions for new markets or improve existing solutions in mature markets. Systems designers select and incorporate battery technologies into their platforms based on specifications and capabilities.
As medical device applications demand larger batteries, it is vital for all members of the chain to understand the increased risks which come from this growth in energy density at the cell, battery, and system levels. All members of this chain must adhere to design principles to ensure that all battery disasters are mitigated before they occur.