Fuel cell vehicles suffer from many problems and one of the bigger ones is that fuel cell systems have very poor volumetric power density leaving very little space for passengers and luggage in the FCV. In fact Panasonics upcoming silicon based lithium battery cells enable building a more compact battery electric power train than will ever be possible with fuel cells. This is shown below:

Volumetric power density of Panasonic’s newest cells: 800Wh/l.1) Discharge efficiency 99% meaning an effective power density of 792Wh/l.

Volumetric power density of compressed hydrogen at 700 bar: 5.6MJ/l = 1555Wh/l. 2) Fuel cells are at most 60% efficient meaning an effective power density of 933Wh/l.

Now, this means that Panasonic’s forthcoming lithium batteries (2012 delivery) are almost as power dense as highly compressed hydrogen when the space for the fuel cell it selves and the high-pressure tanks are ignored for the calculation. If that space is included you will lose minimum 50% more in terms of space as pressure tanks are impossible to build in prismatic shapes as it is possible with battery cells and because the fuels cell stack and it full size cooling grill is very bulky as can be clearly seen in the picture of the Tucson/ ix35 Hydrogen Fuel Cell Electric Vehicle (FCEV). Battery cells also need packaging and a cooling system but the volume loss is more like 20%.

Conclusion

Practical volumetric power density for Panasonic’s new silicon batteries 633Wh/l=(800*0.99*(1-0.2)).

Practical volumetric power density for fuel cell battery 466.5 Wh/l= (1555*0.6*(1-0.5)).

Moreover, Panasonic will be able to continue to improve their silicon based battery cells whereas it is practically impossible to increase the power density of hydrogen in pressure tanks as higher pressure will also lead to bigger pressure tanks.

Hydrogen for vehicle transportation is a dead end for many reasons including non-competitive volumetric power density.

Source 1, Panasonic 800Wh/l cells
Source 2, Hydrogen 1555Wh/l at 700 bar

Sorry and thank you for noticing! I did of cause mean volumetric energy density and not volumetric power density. I very much know the difference between power and energy density. This error is corrected in the text below so please disregard the text in my first post.

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Fuel cell vehicles suffer from many problems and one of the bigger ones is that fuel cell systems have very poor volumetric energy density leaving very little space for passengers and luggage in the FCV. In fact Panasonics upcoming silicon based lithium battery cells enable building a more compact battery electric powertrain than will ever be possible with fuel cells. This is shown below:

Volumetric energy density of Panasonic’s newest cells: 800Wh/l.1) Discharge efficiency 99% meaning an effective energy density of 792Wh/l.

Volumetric energy density of compressed hydrogen at 700 bar: 5.6MJ/l = 1555Wh/l. 2) Fuel cells are at most 60% efficient meaning an effective energy density of 933Wh/l.

Now, this means that Panasonic’s forthcoming lithium batteries (2012 delivery) are almost as energy dense as highly compressed hydrogen when the space for the fuel cell it selves and the high-pressure tanks are ignored for the calculation. If that space is included you will lose minimum 50% more in terms of space as the pressure tanks are impossible to build in prismatic shapes as it is possible with battery cells and because the fuel cell stack and its full size cooling grill is very bulky as can be clearly seen in the picture of the Tucson/ ix35 Hydrogen Fuel Cell Electric Vehicle (FCEV). The battery cells also need packaging and a cooling system but the volumetric loss is more likely to be 20%.

Conclusion

Practical volumetric energy density for Panasonic’s new silicon batteries 633Wh/l=(800*0.99*(1-0.2)).

Practical volumetric energy density for fuel cell battery 466.5 Wh/l= (1555*0.6*(1-0.5)).

Moreover, Panasonic will be able to continue to improve their silicon based battery cells whereas it is practically impossible to increase the energy density of hydrogen in pressure tanks as higher pressure will also lead to bigger pressure tanks.

Hydrogen for vehicle transportation is a dead end for many reasons including non-competitive volumetric energy density.

Source 1, Panasonic 800Wh/l cells
Source 2, Hydrogen 1555Wh/l at 700 bar

Al_vin

In all likelihood it is impossible as the fuel fell stack emit a lot of heat about 40kW in a 100kW stack operating at full power. Wrap that stack around a hydrogen tank and in a few minutes the vehicle will explode. You need to cool the fuel cells almost as much as in a diesel engine as they are only 60% efficient. You need a big grill and you need to keep the hydrogen tank in a safe distance from that heat.

The basic math of fuel cells is they will fill a market segment the car makers NEED. Batteries will fill one section fuel cells anouther and trhe rest will be filled by other fuel sources.

Thing is they need all these segments.

"Adoption of an induction motor instead of a permanent magnet-type motor for cost benefits."

I figured more than a few would catch on to this.

GM had 100 Equinox FCEVs out for testing a while back, we have not heard much about that lately. If this company has enough money to do this, I would be putting some of it into DMFC development.

That does not make a lot of sense. You are recommending that small batteries be "pumped" in? Perhaps a fluid that is used and then reused, but small batteries?

We have a "battery" that is chemically recharged, it is called a fuel cell. Some even run on liquid fuels like methanol either directly or indirectly through a reformer.