2011 Mercedes-Benz F-Cell: Daimler's Serious About Hydrogen

By John O'Dell December 9, 2009


Mercedes Benz's second-genertion fuel cell car, the B-Class F-Cell, on road above Nice harbor in Southern france. 

By John O'Dell, Senior Editor

If the manifestos and speeches weren't enough to convince you that the company that invented the automobile is serious about moving it into a hydrogen age, a spin in the 2011 B-Class F-Cell ought to do the trick.

It did for us, although we have to admit that we've never faltered in our insistence that hydrogen fuel cells are a viable alternative powerplant for emission-free, oil-free driving, and that the automotive part of the technology has been ready for the market for some time now.

As Jorg Prigl, one of our hosts at a Mercedes-Benz TecWeek program that took place in Germany this week (with a day trip to Nice and Monaco on the Cote d'Azure) put it, "our electric car is beyond the car show stage. We have more ready for production than any other" automaker.

Before we cause confusion - when Prigl, Mercedes' vice president of program management for the A- and B-Class and Smart car development programs says "electric" he means fuel-cell electric.That would be vehicles like the F-Cell with electric drive motors powered by combining hydrogen and oxygen in an on-board fuel cell stack in a reaction that produces electrons.



Benz' B-Class-based fuel cell car is a neat package, the compact five-seat hatchback housing the entire powertrain under its hood and under your feet between the panels of a "sandwich" floor brought over from the subcompact A-Class


Cutaway shows location or principal parts of F-Cell's powertrain. Click to enlarge.


That powertrain is built around a fuel cell stack consisting of 380 individual PEM (proton-exchange membrane) cells fed by 3.7 kilograms - 7.1 pounds - of compressed hydrogen gas stored in a trio of tanks at 10,000 pounds of pressure per square inch, or 700 bar as scientists like to measure pressure.

The electricity produced in the 80 kilowatt stack powers a 100 kilowatt - 136 horsepower - electric motor that propels the car with 213 lb.-ft. of torque.


A 1.4 kilowatt-hour lithium-ion battery - of which only 1.12 kilowatt-hours, or 80 percent, is useable, provides low-speed power at start up and gives the fuel cell's output a supercharged 20 horsepower boost when extra acceleration power is needed.

The battery is charged mainly with energy captured by the regenerative braking system - a mild one that doesn't create an unusually strong deceleration when the driver's foot comes off the accelerator.

Excess juice from the fuel cell also can be shunted into the battery to help top it up. It is not a grid-rechargeable, or plug-in, battery and is 20-30 times smaller than the large battery packs needed by so-called pure electric, or battery-electric, vehicles (BEVs).


fcellflow.jpgIn the roughly two hours of driving time we had with the F-Cell on the narrow, twisty roads along the coast from Nice's waterfront airport to a restaurant and meeting room in Monte Carlo's yacht harbor and back again on the toll road traversing the mountains above the two cities, the Mercedes-Benz F-Cell ran like a champ.


Screen shows fue celldelivering half power to F-Cell's electric motor.


Except for the slight whine of the compressor that forces oxygen into the fuel cell stack, the drive was quiet, absent the drone of an internal combustion engine - and the torquey electric drive - while unable in acceleration to hold a candle to the frequent Ferraris we spied - did a workman-like job of pulling us up each hill.

On the highway, the F-Cell showed itself perfectly capable of hitting and maintaining its claimed 105 mph top speed, and with the extra 550-pounds that the fuel cell system brings to the party all most all situated along the centerline beneath the seats, the F-Cell stuck to the ground almost as well as one of the Grand Prix cars that pound Monaco's streets each May.

That's pretty impressive considering that the suspension is unchanged for the lighter gas- and diesel B-Class models except for stiffer springs to handle the extra weight and a lift of "a few millimeters" to keep the top of the wheel cuouts from rubbing the wheels

Braking, helped by the regenerative system, was strng withiugh requiring much effort and the electronically assisted steering, while a bit soft and lacking in feedback, kept the B-Class centered and pointed where you wanted it to go.

Cold Starts

Mercedes claims a range of 285 miles, or the hydrogen-to-gasoline equivalent of 77 miles per gallon, and while doing the whole trip at 100 would drain the tanks a lot faster, a normal mix of city and speed-limit highway driving will probably deliver all that.

While cold isn't much of a problem in Monaco, it freezes quite nicely in Stuttgart - Mercedes' home town - and fuel cells make water (their only emission) than can freeze in the system and hamper startign and initial performance until the cell stack and battery heat up.

It's a problem every fuel cell developer has faced and that most say they've overcome.

Jurgen Banken, manager of fuel cell drive development for Mercedes-Benz, said that the company's engineers have been working on the issue since their first fuel cell was launched in a Mercedes delivery van in 1977.

The B-Class fuel-cell, which eveyone at the company insists is only the second-generation system despite more than three decades of nonstop improvements, takes just seconds to spool up to full capacity at temperatures as low as 5 Fahrenheit and starts well at temperatures down to -13 F, says alternative drive train programs manager Natanael Sijanta.

"It will start even at -40," he said, "but it will take longer to come up to proper operating teperature" and power output will be greatly reduced until that happens.

The F-Cell starts moving with power stored in the lithium-ion battery - it is capable of up to 12 miles of slow-speed all-battery drive - and then the fuel cell takes over, assisted by the battery when an extra shot of power is needed.

When? How Much?

fcellsniceairport.jpgMercedes doesn't have plans to write individual leases at frist, preferring to put the initial batch of 200 F-Cells into fleets.


Mercedes-Benz plans to put 2,000 F-Cell cars into lease programs starting early next year


Half of those vehicles are slated for North America with most of those slated for the relatively hydrogen-rich Southern California area (5 public stations now, 11 by the middle of 2011 and 40 by 2015 if Mercedes' guesstimates are right on).

But company executives have insisted several times now that they will start mass production (in low volumes, no doubt) with real sales, not just leases, in ealry 2015.

Pricing specifics haven't been disclosed - might not even have been figured out yet - but Prigl said Mercedes hopes to ge the price down to the equivalent of a conventional, well-equipped C-Class by the time sales start in 2015 - so figure $50,000 or so.

The real cost of a fuel cell car is still pretty high, no matter who is making it.

Beause there are so few around, there's no supplier base for the necessary high-tech components, hus no competitive pricing and no economies of scale.

Most fuel cell cars and SUVs are pretty much hand built at the factory and those that have been leased so far have been heavily subsidized.


A $50,000 price tag would leave a lot of us with our noses pressed to the showroom window, but its not unreasnable for a high-tech, oil-free car with the pie-plate sized three-pointed star blazing from its grille.

To help make it more palatable, Prigl said the company expects a life-span of 12 years or more from the fuel cell stack and battery when the 2015 models go on sale and is warranting the first leased models for the full four-year lease period.

Those initial leases will expire in by 2015 becase Mercedes anticipates a next-generation fuel cell system by then and doesn't want its first customers to be stuck with old school technology, he said.

He also suggested that there may be other models available using the same platform that underpins the A- and B-Class models; if not in 2015 then soon after.

The Flaw

FCellFueling.jpgDespite all the enthusiasm and assurances that the technology is ready for market, there is a big stumbling block still to overcome.

Just as battery-electric cars cannot go without chargers and gasoline or diesel cars need fuel stations, hydrogen fuel cell vehicles need sources of compressed hydrogen

The devil's not in the details of how to build a reliable, durable fuel cell car or truck able to compete favorably against oher alternative technologies and conventional vehicles in today's market, Prigl said,

Rather, the hang-up is in the hows and whens of building a fueling infrastructure to supply the necessary hydrogen using electricity from clean, renewable resources.

That's not directly the auto industry's problem - unless we want them owning the fuel we have to buy to make the cars we buy from them run; it would be like turning auto manufacturing over the Exxon Mobile, not a good idea.

But it is a concern and Mercedes and other fuel cell developers are lobbying in the U.S. and Europe to get funding to help entrepreneurs set up public hydrogen fueling station networks.

So far, most of the successes have been in Europe, where a company like Mercedes has the abiit to work directly with national governments. 

Not Alone   

Mercedes-Benz isn't alone in the fuel cell field. Ford, GM, Toyota, Honda,  Hyundai, Kia, Nissan and Renault all lre working on vehicles that use them.

Honda's FCX Clarity and GM's Equinox FCEV already are deep into pubic demonstration programs aimed at showing Joe and Jane Consumer (and politicians and energy honchos as well) that hydrogen needs to be part of any well-thought energy independence or green motoring plans.

Toyota also has leased a limited number of its next-generation, Highlander-based FCHV-Adv fuel cell SUVs (all those letters stand for Fuel Cell Hybrid Vehicle-Advanced) to a number of university and government agencies and research programs in California and, shortly, New York.

Mercedes' F-Cell will be next up and it was to drum up enthusiasm for the project - and to get word out of the improvements it has brought to its fuel cell technology in recent years - that Mercedes-Benz invited a number of journalists from around the globe to come to Monaco the other day for an F-Cell test drive and half-day workshop.

fcellcotedazure.jpgWhy Monaco?

The ritzy principality - famed for its casino, the multimillion-dollar yachts in its harbor and the anual Formula 1 race that bears its name (not to mention its ruling Grimaldi family and the late Princess Grace)  - wasn't selected for its wealthy populace, which some wags suggested would be the perfect customer base for the F-Cell's still very expensive technology.

And while it is a lot easier to get a bunch of car writers to travel to Monaco for a day trip than, say, to New Jersey, that wasn't the reason either, our hosts insisted. Nor was a desire by a contingent of Daimler engineers and program managers to get away from a rainy, chilly Stuttgart much of a factor.

Instead, Mercedes picked Monaco because of the commitment its head of state, Prince Albert II, has made a priority of greening up the tiny city-state and sponsoring the use of zero emissions vehicles such as the F-Cell and the upcoming Smart EV (not that we saw any while we were there).

That's what Prigl told us told us, anyhow, as he described how Mercedes sees fuel-cell electric vehicles as the long-range personal transportation providers in an oil-constrained future, with battery-electric vehicles serving as families' secondary vehicles for daily commuting and other short trips.

Point of Change

Until those two types of vehicles take over, though, Mercedes and lots of other automakers and policy makers expect continually improved conventional gas and diesel engines and hybrid-electric vehicles - including plug-in hybrids - to dominate.

The tipping point to all-electric drive will come when oil prices rise to the morbidly painful (pundits are all over the board on how much that will be, with estimates ranging from $6 to $10 or more a gallon) or when - for environmental, political or security reasons - oil is no longer permitted to be used as a fuel feedstock for private transportation.

It's encouraging to see car makers actually getting out ahead of the curve for a change. It will be a pretty horrid world if the cars aren't ready when the crude runs out.

And if that means selling them to every millionaire on the Riveria to get volume up and prices down so I can afford one, so be it.

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davemart1 says: 4:19 AM, 12.10.09

In my view Peugeot with this little plug-in fuel cell convertible have made far better design choices:
There are several advantages to having relatively large batteries in a fuel cell car.
In the early days there are not going to be many hydrogen fuelling stations, so it will be far more convenient if you can do your day-to-day running around on batteries and only use the fuel cell when you go for a run, when the fuel cell is most useful.
This also means that the cost of building the hydrogen infrastructure is greatly reduced, as you would only need fuelling stations on main routes and would not need to duplicate every single petrol pump.
Infrastructure costs would be perhaps a fifth of that of simply replacing petrol with hydrogen.
It is also inherently less efficient to produce hydrogen than to charge a battery.
Since you would only be using hydrogen part of the time in a plug-in, this becomes much less important and it doesn't cost so much to run the car.
You don't need nearly as powerful a fuel cell, which will greatly reduce costs even though you obviously have to pay more for the more powerful batteries.
Since you would only run the fuel cell some of the time, it is a lot easier to get decent longevity from the cell.

So why not just use a conventional engine, like the Volt?
As a fuel cell plug in would be all electric whatever the mode, they are inherently much simpler and do not rely on fossil fuels, the two technologies of batteries and fuel cells are synergistic and both cover the deficiencies of the other.

Battery cars with fuel cell extenders are a nearly ideal solution to personal transport.

thejohnp says: 4:45 PM, 12.10.09

Isn't Mazda testing a hydrogen/gasoline hybrid? That would seem to be a viable solution until the fuel cell infrastructure is there.

mcmanus says: 7:52 AM, 12.18.09

Fuel cells are the long term solution. We cannot ravage the planet enough to provide the amount of batteries needed for all the cars in the world. (Northern Canada is currently being turned into a lunar landscape trying to supply hybrid car batteries.) Those batteries need replacing and disposing of. Furthermore batteries are heavy, and so counter-productive in a vehicle.

Hydrogen production fits very well into green energy sources as it can be stored when sunshine or winds aren't available. There are hydrogen filling stations now in Norway that are solar powered and about the size of a Coke machine. Honda at one time was proposing to lease the FCX with such a plug-in setup for home use. Being a stored fuel, hydrogen can also be distilled at night while power plants are still running and demand is otherwise low.

Since hydrogen can be produced locally it doesn't have to be shipped/piped thousands of miles like fossil fuels, thus saving more energy/costs. Hydrogen filling stations would only serve vehicles a long way from home or big city dwellers. We don't need Exxon or any big companies to build corner hydrogen distilling stations.

mcmanus says: 1:38 AM, 12.20.09

12 year life span for the fuel cell/battery by 2015 looks very attractive. Again, we don't need a whole new infrastructure to supply hydrogen, just a standardization of the delivery nozzles and pressures.

I vote against hybrids as more complex, expensive, and heavy (all aspects that don't make sense in a moving asset that depreciates and you need not to break down).

So I support clean diesel as an intelligent alternate to the current gasoline/battery hybrids (they should last much longer, get comparable mileage, use up less resources to build/maintain, are much simpler designs, and cost about the same to buy).

Clean diesel can also be applied to other vehicles (semi's, tractors, construction equipment, etc.). Can you imagine how heavy a gasoline/battery hybrid semi would be or the driver waiting 8 - 24 hours for a recharge before going the next 200 or so miles?


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