Advances in hydrogen storage technologies

Abstract

Gaseous hydrogen storage is the most mature technology for fuel cell vehicles. The main safety concern is the catastrophic consequences of tank rupture in a fire, i.e. blast waves, fireballs, and projectiles. This paper summarises research on the development and validation of the breakthrough microleaks-no-burst (μLNB) safety technology of explosion-free in any fire self-venting Type IV tanks that do not require a thermally-activate pressure relief device (TPRD). The invention implies the melting of the hydrogen-tight liner of the Type IV tank before the hydrogen-leaky double-composite wall loses load-bearing ability. Hydrogen then flows through the natural microchannels in the composites and burns in microflames or together with resin. The unattainable to competitive products feature of the technology is the ability to withstand any fire from smouldering to extreme impinging hydrogen jet fires. Innovative 70 MPa tanks made of carbon-carbon, carbon-glass, and carbon-basalt composites were tested in characteristic for gasoline/diesel spill fires with a specific heat release rate of HRR/A = 1 MW/m². Standard unprotected Type III and IV tanks will explode in such intensity fire. The technology excludes hydrogen accumulation in naturally ventilated enclosures. It reduces the risk of hydrogen vehicles to an acceptable level below that of fossil fuel cars, including underground parking, tunnels, etc. The performance of self-venting tanks is studied for fire intervention scenarios: removal from fire and fire extinction by water. It is concluded that novel tanks allow standard fire intervention strategies and tactics. Self-venting operation of the 70 MPa tank is demonstrated in extreme jet fire conditions under impinging hydrogen jet fire (70 MPa) with huge HRR/A = 19.5 MW/m². This technology excludes tank rupture in fires onboard trains, ships, and planes, where hazard distances cannot be implemented, i.e. provides an unprecedented level of life safety and property protection.