Technical Challenges and R&D Needs for Compressed Hydrogen Storage On-Board Fuel Cell Electric Vehicles

A primary goal of the Hydrogen Storage Program (the Program), part of the U.S. Department of Energy’s Fuel Cell Technologies Office, is to develop and demonstrate advanced hydrogen storage technologies to enable successful commercialization of fuel cell products. Compact, reliable, safe, and cost-effective storage of hydrogen is a key technology requirement for the widespread commercialization of Fuel Cell Electric Vehicles (FCEVs) and other hydrogen fuel cell applications. While some light-duty FCEVs with a driving range of about 300 miles are emerging in limited markets, affordable onboard storage still remains a roadblock to commercialization beyond limited vehicle platforms and niche markets. A key challenge is how to cost effectively store sufficient quantities of hydrogen onboard without sacrificing passenger and cargo space. While the energy per mass of hydrogen is substantially greater than most other fuels, its energy by volume is much less than liquid fuels, such as gasoline. The current state of the art is to store hydrogen in Composite Overwrapped Pressure Vessels (COPVs) with polymer liners at 700-bar pressure. The following is an overview of technical challenges and R&D needs to enable successful deployment of high-pressure hydrogen storage systems into commercial FCEVs. These technical challenges primarily concern the contributions of composite materials to compressed hydrogen storage system cost, mass, and volume. To achieve the performance requirements for FCEVs, the Program, with input of US automobile manufacturers, has developed 2020 performance targets for onboard hydrogen storage that include costs of $10/kWh, gravimetric density at 1.8 kWh/kg system, and volumetric density at 1.3 kg H2/L system to provide for a driving range of at least 300 miles. The Program is developing strategies and supports R&D efforts to address composite materials for high-pressure COPV use with FCEVs. Examples of projects and activities the Program has supported are provided for illustrative purposes.