Using Fuel Cells to Increase the Range of Battery Electric Vehicles

Feb. 3, 2014 | By Julia Thomas | Contact media relations

A team of NREL analysts identified potential cost-effective scenarios for using small fuel cell power units to increase the range of medium-duty battery electric vehicles (BEVs).

BEVs offer great potential for decreasing lifecycle costs in medium-duty applications, a market segment currently dominated by internal combustion technology. Characterized by frequent repetition of similar routes and daily return to a central depot, medium-duty vocations such as parcel delivery are well positioned to take advantage of the low operating costs of BEVs.

Unlike conventional vehicles, however, BEVs are constrained by long recharge times and a spotty public charging infrastructure. Consequently, the current BEV market is largely limited to vocations where planned routes don’t exceed the vehicle’s battery range.

With a focus on cost effectively boosting BEV range and increasing market appeal, NREL analysts investigated the use of small electricity-producing hydrogen fuel cell stacks to supplement the vehicle’s battery pack as it nears depletion.

This arrangement leverages the low cost of grid electricity for most of the miles traveled while enabling the use of hydrogen fuel for range extension when necessary. By using hydrogen as a range-extending fuel, the BEV can retain its zero-tailpipe-emission capability as well as its potential for operating on 100% renewably generated energy.

The NREL team found that small fuel cell power units provide extended range at significantly lower capital and lifecycle costs than additional battery capacity alone. And while fuel-cell range-extended vehicles are not economically competitive with conventional vehicles given present-day economics, NREL identified potential cost-competitive future scenarios that take into consideration component costs and configurations, duty cycles, and energy costs.

Performed in collaboration with industry partners and the Fuel Cell Technologies Office in the U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy, NREL’s analysis employed real-world vocational data and near-term economic assumptions to (1) identify optimal component configurations for minimizing lifecycle costs, (2) benchmark economic performance relative to both battery electric and conventional powertrains, and (3) understand how the optimal design and its competitiveness change with respect to duty cycle and economic climate.

For more information, refer to the conference paper—titled “Overcoming the Range Limitation of Medium-Duty Battery Electric Vehicles through the Use of Hydrogen Fuel Cells”—presented at the Society of Automotive Engineers 2013 Commercial Vehicle Engineering Congress.