Jun 27, 2008

Is Fuel-cell Car Really Ultimate Solution?

Attended the line-off ceremony for Honda's "FCX Clarity" fuel-cell vehicle June 16. At the ceremony, saw part of the company's fuel cell stack manufacturing process, which is usually kept secret, as well as its automotive assembly process.
One of the FCX Clarity's features is its very compact fuel cell stack, which is installed in its floor tunnel. Housing no engine in its front area, the FCX Clarity realized a low, smooth body, which is an unprecedented design for fuel-cell vehicles (FCVs). It definitely looked different from existing FCVs, most of which mount fuel cells under the floor.

To realize a design that is difficult for engine cars, Honda Motor Co Ltd developed both platform and chassis exclusively for the FCX Clarity, although it only plans very limited global sales of about 200 units over the next three years.

Commenting on this point, Honda's enginner engaged in the development said, "To highlight the attraction of FCVs, we needed to embody and show a design and a package that only FCVs can realize. Our proposal was approved by the upper management and resulted in this design."

I was given a chance to steer the car by myself at this event. Amid the low noise from the blower that was sending air to the fuel cells and the increasing road noise, I felt a sense of driving with powerful acceleration, as if something was pushing my back. It gave me an enjoyment of driving that was completely different from engine cars.

The key feature of FCVs is their low impact on the environment as they use hydrogen as fuel and only emits water during the drive. Due to this environmental property, they are often called the "ultimate eco cars." However, we have insisted for some time that we believe electric vehicles (EVs) are more promising than FCVs.

In fact, FCV technology is advancing. The fuel cell stack that Honda incorporated in the FCX Clarity this time achieved a 50% higher capacitance density and a 67% improved mass output density compared with the previous FCX. Also, it realized low-temperature startability, which has been regarded as a challenge that FCVs must overcome, at -30°.

Another challenge that FCVs are facing is a manufacturing cost, but I felt it can be reduced considerably if the company further enhances processes of press-forming stainless separators and layering cells into stacks, which have already been partly automated.

Regardless of these advantages, however, we still consider EVs are more promising because of the fact that FCVs primarily use hydrogen, rather than fuel cells, as fuel.

As hydrogen is rare in nature, we must generate it by using other energy resources such as fossil fuel. The cheapest measure at present is to derive it from natural gas, but nearly 40% of the energy is lost during the manufacturing and transport phases. In addition, as a vapor energy, hydrogen requires large tanks for transport, and supply infrastructure has not yet been established. Any of these issues cannot be solved immediately.

Based on these factors, Toyota Motor Corp and Nissan Motor Co Ltd, for example, appear to be on the verge of shifting their development focus to plug-in hybrids and EVs (See related article). Nevertheless, Honda is focusing on FCVs, without developing EVs (at least officially).

During a Q&A session, Honda's President Takeo Fukui cited "the EV's inability to secure a sufficient cruising distance" as the reason why the company persists in the FCV development.

"Under the current circumstances, the FCV is the only solution to achieve zero CO2 emissions while ensuring convenience comparable to existing automobiles," Fukui said.

In fact, it is true that the cruising range of EVs is insufficient, despite the improved performance of the Li-ion secondary batteries they use. The practical cruising distance is roughly 100km at most, I suppose.

However, there is another perspective that we can overcome such issues not only by upgrading cell performance but also through the overall social system. Considering most drivers do not often drive more than 100km at a time, it might be sufficient if they usually charge EVs at home using midnight power and at scattered high-speed charging stations for occasional long-distance drives.

Honda itself does not deny the possibility of Evs. "We can create an EV based on the elemental technologies that we applied to the FCX Clarity if a cell with innovative performance emerges," Fukui said. As both FCVs and EVs use motors for driving, I believe they share the sense of acceleration that I found to be different from that of engine cars.
Source: tech-on

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