|A rendering of a projected advanced CH2 storage system.|
Quantum Technologies outlined a development path for its compressed hydrogen (CH2) storage systems that shows the company meeting the US Department of Energy’s 2010 hydrogen storage gravimetric density target.
Speaking at the Zero Emission Vehicle (ZEV) Symposium being held by the California Air Resources Board, Andy Abele, Quantum’s executive director of strategic development, also noted that the volumetric targets will not be met with the compressed hydrogen systems.
Quantum provides powertrain engineering, system integration, and manufacturing of packaged fuel systems and accessories for specialty vehicles and applications, including fuel cells, hybrids, alternative fuels and hydrogen refueling.
|Quantum 70 MPa compressed hydrogen storage system. Click to enlarge.|
The company has converted a number of Priuses to hydrogen-fueled hybrids, and is also the supplier of the 70 MPa storage systems for the just-announced GM Equinox Fuel Cell vehicle (earlier post), as well as to GM’s Sequel, HyWire and HydroGen 3, and for the Suzuki WagonR.
Compressed hydrogen storage technology is doing well in some areas, such as cycle life, and the cost of the storage tanks is improving. However it is not meeting gravimetric or volumetric targets set by DOE. The energy density, Abele noted, “is what it is.”
About 65% of the cost of the storage systems costs are now the carbon fiber, Abele said. The storage tank industry is competing with aerospace and renewable energy producers (windmills) for the necessary carbon fibers.
Carbon fiber producers, who suffered a glut of capacity in the late 1980s and early 1990s, are increasing capacity, but slightly trailing demand. Given those conditions, it will be a challenge to get system costs down significantly, Abele said, unless there is some breakthrough in fiber manufacturing.
Using a pressure lower than 70 MPa (10,000 psi) could optimize the costs, but storage suppliers encounter resistance to that from OEMs who look to the higher pressures to provide more hydrogen to enable a longer driving range.
Quantum has a plan to meet or beat the 2010 DOE gravimetric standard of 2.0 kWh/kg with an advanced manufacturing program that will include:
- A storage-centric vehicle design that uses a single, longitudinal 160-liter, 70 MPa storage module running down the centerline of the vehicle. The placement, for one thing, improves safety and can minimize some of the additional system weight currently required for mounting.
- External low-cost pressure regulation components rather than in-tank systems.
- Embedded sensors in the tank to monitor its health to allow reduction of some of the weight currently specified for safety purposes.
- Integrated filament winding w/ fiber placement to use no more fiber than required, along with accompanying revisions of codes and standard enabling that fiber placement.
- Chilled hydrogen supply for fast fill.
Compressed [hydrogen storage] works, but it is not without its issues. It is enabling vehicles to get on the street and allowing people to get familiar with hydrogen technology.—Andy Abele
|Quantum and DOE Storage Targets|
|* Single 160-liter, 70 MPa tank, 500K production volume, optimized carbon, health-monitored storage system.|
|Usable Specific Energy
|Usable Energy Density
(Cycles, ¼ tank to full)