US Patent 11300360 Pressure vessel with barrier passage containing fire suppressant elements

A pressure vessel includes a first wall defining a container and a second wall surrounding the container defining a cavity between the first wall and the second wall. The pressure vessel also includes a vent in the second wall providing fluid communication between the cavity and an outside of the second wall and matter positioned within the cavity configured to prevent flame from propagating through the cavity while providing thermal conductivity between the first wall and the second wall.