Patent ID: 8663824

Claim:
A battery pack thermal management system, comprising: a sealed battery pack enclosure configured to hold a plurality of batteries; and an exhaust nozzle assembly, wherein said exhaust nozzle assembly is comprised of: an exhaust nozzle integrated into an outer wall of said sealed battery pack enclosure, wherein said exhaust nozzle is configured to pass and direct gas from within said sealed battery pack enclosure to an ambient environment external to said sealed battery pack enclosure; a nozzle seal mounted within an exhaust nozzle aperture, wherein said nozzle seal seals said exhaust nozzle during normal operation of said plurality of batteries within said sealed battery pack enclosure; and a shape memory alloy (SMA) seal retaining member fabricated from a shape memory alloy (SMA), wherein said SMA seal retaining member is configured to have a first shape and a second shape, wherein said SMA seal retaining member transforms from said first shape to said second shape when heated to an SMA transformation temperature, wherein said SMA seal retaining member in said first shape captures an end portion of said nozzle seal and holds said nozzle seal within said exhaust nozzle, wherein said SMA seal retaining member transforms from said first shape to said second shape when at least one of said plurality of batteries enters into thermal runaway and an internal temperature of said sealed battery pack in proximity to said SMA seal retaining member exceeds said SMA transformation temperature, and wherein said SMA seal retaining member in said second shape releases said end portion of said nozzle seal and allows said nozzle seal to be permanently ejected through said exhaust nozzle due to an increased internal battery pack pressure that accompanies said at least one of said plurality of batteries entering into thermal runaway.