Automotive

Nissan doubles power density with new Fuel Cell Stack

Nissan doubles power density w...
Nissan yesterday revealed a new Fuel Cell Stack for Fuel Cell Electric Vehicles (FCEV) that packs 85 kilowatts into a 34-liter package
Nissan yesterday revealed a new Fuel Cell Stack for Fuel Cell Electric Vehicles (FCEV) that packs 85 kilowatts into a 34-liter package
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Nissan's new Fuel Cell Stack for Fuel Cell Electric Vehicles (FCEV)
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Nissan's new Fuel Cell Stack for Fuel Cell Electric Vehicles (FCEV)
Nissan yesterday revealed a new Fuel Cell Stack for Fuel Cell Electric Vehicles (FCEV) that packs 85 kilowatts into a 34-liter package
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Nissan yesterday revealed a new Fuel Cell Stack for Fuel Cell Electric Vehicles (FCEV) that packs 85 kilowatts into a 34-liter package

One area of energy storage that appears to be moving towards viability quicker than battery technology at present is the hydrogen fuel cell. Nissan Motor yesterday revealed its next generation Fuel Cell Stack (2011 Model) for Fuel Cell Electric Vehicles (FCEV).

Through improvements to the Membrane Electrode Assembly and the separator flow path, Nissan has improved the power density of the Fuel Cell Stack to 2.5 times greater than its 2005 model, and in so doing has created a world's best 2.5 kW-h per liter power density.

The cost of the 2011 model Fuel Cell Stack has been reduced to one sixth of the 2005 model.

Furthermore, molding the supporting frame of the Membrane Electrode Assembly (MEA) integrally with the MEA's single-row lamination has reduced its size by more than half compared to conventional models.

Compared with the 2005 model, both the usage of platinum and parts variation has been reduced to one quarter, thereby reducing cost of the Next Generation Fuel Cell Stack to one-sixth of the 2005 model.

In so doing, Nissan engineers have achieved an important breakthrough with the development of a compact and durable hydrogen fuel-cell stack - capable of delivering ample power - that can be manufactured in volume at competitive cost.

Most importantly, it's not one of those Japanese research lab breakthroughs that's still effectively ten years away. Nissan's fuel-cell team says it can be ready for market as soon as sufficient supplies of hydrogen are available.

According to Nissan, taxis, delivery vans and other city-specific fleets could quickly be converted to zero-emission fuel cells.

"We never got discouraged and we never gave up," says Masanari Yanagisawa, a 10-year veteran in the company's fuel-cell R&D efforts. "So we just kept working, patiently and persistently. As a result, we have achieved what we believe is a major breakthrough.

"We have made great strides in two critical areas: power density and cost. Our 2011-model fuel-cell stack delivers power density at 2.5 kilowatt-hrs per liter, 2.5 times better than our 2005 model.

"As a result, the new stack is also a lot smaller. We can now pack 85 kilowatts of power in a 34-liter package. Better yet, we have brought the production cost down by 85 percent, close to meeting the U.S. Department of Energy cost target for 2010 - a widely referenced benchmark.

"We slashed the price by reducing the need for platinum by 75 percent," Yanagisawa says. "The Membrane Electrode Assembly [MEA] comprises 80 percent of the stack's cost, and platinum is half the cost of an MEA, so this was a huge step forward."

The other key challenge in developing fuel-cell stacks is to design a structure that delivers high power- density; that's durable and easy to manufacture without flaws. This is very tricky.

Each fuel cell is a carefully built sandwich with layers ultra-thin polymer electrolyte membrane. Each membrane has an anode layer and a cathode layer on both sides. On the outer side of each of each of these anode/cathode layers are separators, which form channels through which hydrogen, air and cooling water flow.

As each fuel cell generates a maximum of one volt, you need to stack lots of sandwiches together to get enough power to run a car.

The process is so fiddly that building a model ship in a bottle seems a snap by comparison. No wonder so many teams around the world have given up in frustration. But with their craft legacy of patient attention to minute detail, this is the kind of work that Japanese tend to excel at.

Since 2001, the Nissan team has built a succession of prototype fuel-cell vehicles, first with partners like Ballard Power Systems and UTC Fuel Cells, then in-house from 2005. Each stack was incrementally better than its predecessor.

The 2005 prototype achieved a range of 500 kilometers, matching a conventional car. A 2008 version achieved an important breakthrough in cold-weather tolerance. But putting enough cells together in a durable stack was a hurdle the team just couldn't get over. After managing to stack more than 400 cells, they would watch in frustration as the brittle contraption fell apart on the lab floor.

Finally, in 2009, the team had a conceptual breakthrough with a technique that involves molding plastic around the MEA to create insulating frames between each of 400+ layers in the stack - thereby ensuring the layers neither short out nor fall apart.

"This breakthrough puts us, no question, in the front rank of fuel-cell developers around the world," Yanagisawa says. "Best of all," he adds with a grin, "it puts us ahead of our competitors."

So can we expect to see a Nissan Fuel Cell Electric Vehicle (FCEV) coming round the corner soon? "We are now ready to go to market at any time," Yanagisawa says. "The only hurdle remaining is hydrogen distribution. Give us the hydrogen and we'll give you an FCEV. We're good to go!"

16 comments
HansMMN
Someone is confused. 85 kW in 34 liters. For how long? 1 second or 1 hour or 10 hours? Or did you mean 85 kWh? Remember the 125 million US$ Mars Lander that crashed because the engineers fouled up on the units.
Robert Newman
With hydrogen, you have a chicken vs. egg adoption scenario which is often very slow. Why not design around methane (natural gas) as the fuel? It already has a wide distribution network. Methanol would also be a better choice than hydrogen since it has a high storage density compared to hydrogen gas. Sure, hydrogen leaves no CO2 behind, but given then costs and time to roll out a hydrogen network, it may be a while before you can buy a hydrogen car. These fuel cells would be ideal for home power use, especially when supplemented by solar or wind generation.
Stewart Mitchell
This is a fuel cell. The power will be constant as long as the fuel last.
Eletruk
You are confusing power density with energy density. What they are saying is that the powerplant can put out 85kW of power, and the volume of space it takes to do that is 34 liters. So that translates to 2.5 kW/liter. How long that is output for depends on how big your Hydrogen tank is.
EinSascha
@HansMMN. This is a hydrogen fuel-cell, not a battery. The energy (kWh) is in the hydrogen. The fuel-cell only converts it into electrical power (kW).
Stewart Mitchell
An electric bike is 500 watts. That should be 200 ml inverter. Sounds good
Eric Grant
The article is refering to power density which is kW per Liter, not efficency which would be kWh per Liter. A Fuel cell does not store energy like a battery so it\'s not measured in kWh. The 85 kW in 34 liters is akin to saying my car has a 300 bhp 4.6 Liter engine. In an internal combustion engine the volume is the engine displacement but for a fuel cell I believe that it is the volume of the stack.
The reason they find power density important is because cars need a small fuel cell that put out a large amount of power, as opposed to industrial sized fuel cells that don\'t need to move and can be as big as they want.
Facebook User
I think you are right they have their volume units a wee bit wrong. Now if that was 3.4 litres that is impressive.
Natural gas /methane doesn\'t work in low temp pem cells. It does work quite nicely in SOFC types that run at much higher temps.
Michael Mantion
Hans they are reffering to the volume of the fuel cell not the fuel. Just like the displacement of an engine, not the size of the gas tank
offthegrid
Why is the expected cost such a big secret? Einstein himself after reading this never ending parade of stories couldn\'t say how much \"thereby reducing cost of the Next Generation Fuel Cell Stack to one-sixth of the 2005 model\" is. Can the writer or anyone else tell me how much in dollars one-sixth of the 2005 model is? Bullfreathers! This is yet one more smoke and mirrors look what\'s coming happy things. Good job reporters, another article about what is \"not here on sale yet, look what tomorrow will bring story. And you can forget a 200ml pack for your bike being on the shelf any time soon. Poor people, keep peddling, you wont be able to afford it if one if it ever comes out.