U.S. patent application 20180375402 (applicant Covidien LP, Mansfield, Mass.):
"Systems and methods are discussed herein for cooling a surgical handset using a phase-change material. A container filled with a phase-change material may be telescoped over a heat-generating mechanism of a surgical handset, such as a battery and/or a motor. When the surgical handset is activated, the heat generated by the heat-generating mechanism is absorbed by the phase-change material in the container, which transitions from a first phase to a second phase."