Can Fuel Cells Help the Battery EV Market?

By · May 11, 2011

I have been making the argument recently that fuel cells and batteries are complementary vehicle technologies with fuel cells applicable to larger vehicle platforms with longer duty cycles than pure battery EVs are. However, today’s blog post looks at another more literal way for fuel cells and BEVs to complement each other: using fuel cells as range extenders for BEVs.

It is important to note that all FCVs are in fact hybrid electric vehicles and already feature a fuel cell-battery drivetrain (a few are using ultracapacitors). The battery can take some of the peak power needs, thereby reducing the size of the fuel cell, and allow regenerative braking. In this configuration, the fuel cell provides primary propulsion and is typically sized from 80 to 100 kW.

Fuel Cell Range Extender

Smith HyRange Electric Truck With Fuel Cell Range Extender

Some companies are switching this configuration and placing very small fuel cells into battery EVs as an onboard charger. At last month’s Electric Drive Transportation Association conference in Washington D.C., U.S. company Nuvera and U.K. company Intelligent Energy each discussed their work on this concept. According to Nuvera, their lab simulator of a 20-kW PEM fuel cell coupled with a battery increased BEV range from 59 to 162 miles. Obviously, it remains to be seen how this will translate into a real vehicle platform, but that is an impressive improvement. Intelligent Energy has paired its PEM fuel cells with batteries in several vehicle platforms, including a scooter, small delivery van, and a London black cab.

A key question for this concept will be how to distribute the hydrogen? EnerFuel, a subsidiary of battery manufacturer Ener1 Inc., is hoping to address this question by integrating a high temperature PEM fuel cell which can run off of conventional fuels.

The company’s strategy is to combine a 1-20 kW high-temperature PEM with an onboard reformer that can reform any commercial fuel, including gasoline, to hydrogen. It is not a new concept to use a reformer with a fuel cell car. Several auto OEMs tried this approach in the early days of FCV development, as a way to avoid the problem of hydrogen infrastructure, only to abandon it as an overly complicated, and expensive, engineering challenge. Enerfuel says that high temperature PEM (HT-PEM) fuel cells make this concept viable. Since HT-PEMs are more tolerant of carbon monoxide (CO), EnerFuel’s system does not have onboard CO removal, one of the major engineering challenges.

Enerfuel Comparison

Rather remarkably, EnerFuel also projects that this fuel cell-battery hybrid BEV can be less expensive than a full battery EV because a smaller battery can be used and the fuel cell balance of plant is also reduced.

The fuel cell range extender is still a work in progress, mainly in the lab testing and demonstration vehicle phase, but it will interesting to see if this concept works to help make pure BEVs more than a commuter car.

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