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Hydrogen Storagefor Automotive Applications

Alvaro Amieiro

Hydrogen

H2

• Universe most abundant element

• Odourless and colorless gas.

• Boils at –253 o C.

• Density is 0.0899 grams/liter.

• 1 Kg of hydrogen contains the same amount of energy as 2.1 Kg of natural gas or 2.8 Kg of gasoline.

• Is not toxic and it’s combustion generates water.

Source Wilkipedia

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55MJ/Kg

40 MJ/Kg

120MJ/Kg

H2CH4Gasoline

Hydrogen Mass Energy Density

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0

5000

10000

15000

20000

25000

30000

35000

H2 CH4 Gasoline

MJ/

m3

Gas 350 bar

Gas 700 bar

Liquid

0

5000

10000

15000

20000

25000

30000

35000

H2 CH4 Gasoline

MJ/

m3

Gas 350 bar

Gas 700 bar

Liquid

Hydrogen volumetric energy density

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Alvaro Amieiro

Hydrogen

“There is, therefore, nothing to fear. As long as the earth is inhabited it will supply the wants of its inhabitants, and there will be no want of either light or heat as long as the productions of the vegetable, mineral or animal kingdoms do not fail us. I believe, then, that when the deposits of coal are exhausted we shall heat and warm ourselves with water. Water will be the coal of the future."

Jules Verne The Mysterious Island

Chapter 33

Alvaro Amieiro

DTI acknowledges that ‘..hydrogen storage is the fundamental technical barrier to the more widespread use of hydrogen’

www.dti.gov.uk/renewables/publications/pdfs/technologies/tech11.pdf

Hydrogen Economy Bottleneck

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0.7 - 1 V0.5 A cm2

For example a 500cm2

Cell has around 250 W Output

Hundreds are needed to achieve a

50-100 kW stackNeeded for a

Vehicle

Fuel Cell Requirements

Source Ballard

Source Fuel Cell Today

Volt=Jule/Culomb=Watt/Amp

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Fuel Cell Car Requirements• Typical Example :

– 75 kWel with 5 to 6 Kg H2 to cover 300 miles– Total tank mass 100 Kg total volume 150 l

• Typical System requirements– 10-30 kJ/mol process (20 – 100 C)– Delivery rate (0-7.2 kg/h)– 1.2 kg H2 refuelling time / min– Work in T range – 40 to 70 C

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Excellent range of 300km and the ability to go into very cold conditions. The vehicle features a 150 liter hydrogen tank and

a fuel cell coupled with a 152 volt battery that helps produce 80 kW of power and achieve a speed of up to 90 mph.

Hyundai FCEV

Source HyundaiSource Hyundai

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Motor Max. Output 95kW (129PS, 127 horsepower)

Max. Torque 256N-m (26.1kg-m, 188.8 lb-ft.)

Type AC synchronous motor (Honda Mfg.)

Fuel Cell Stack Type PEMFC(proton exchange membrane fuel cell, Honda Mfg.)

Fuel Type Compressed hydrogen

Storage High-pressure hydrogen tank (350atm)

TankVolume 171 litersDimensions (L × W × H) 4,760 × 1,865 × 1,445mm

(187.4 × 73.4 × 56.9 inches)

Max. Speed 160km/h (100 mph)

Energy Storage Lithium Ion Battery

Vehicle Range 270 miles

Honda FCX

Source Honda

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Opel ZafiraFuel cell in Opel Zafira

200 fuel cells in series produce 125 to 200 volts. Top power 94 kW. The power density is 1.6 kW per liter or 0.94 kW per kg.

Tank specs:4Kg 133KWh 400Km range 200kWh are needed during the hydrolysis,liquefaction and transport.Can keep hydrogen the for 14 days. Source GM

Source GM

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DOE Targets for 5 kg. of Hydrogen System

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DOE Targets 2005 -2015

• 5 Kg of H2 required to make 300miles (500 km.)– 5Kg of H2 ( RT V=56m3 with167 kWh power eq.)

• System Weight 55 - 110 Kg• System Volume 62 - 139 litters• Should refuel between 2.5 min to 10min

Is roughly the equivalent of fitting the volume of a kidney pool of H2 into a large bin in 2.5 min.

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Hydrogen Storage Systems

• Compressed H2 storage– Safety Issues – Compressed state of art is 350 bar.

• 0.03 Kg H2/l this is 5Kg in a 180 L Tank– Expensive materials needed.

• Polymer and Carbon fibbers– Even at 700 bar 1.38 kWh per litter are

achieved. • 133 l tank to host 5kg H2

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Hydrogen Storage Systems

• Liquid Hydrogen:– Cryogenic storage at – 253 deg C– 30% of the energy content needed to

liquefy H2

– 1 to 3% boil off rate– Expensive Insulation filling port

inner vessel

liquefiedH2(-253 °C)

supension

safety valve

outer vessel

shut-off valve

Cooling water heat exchangerelectrical heater

Reversing valvegaseous/liquid

liquid extractiongas extraction

filling lineLevel probe

Super-insulation

gaseous H2(+20 °C bis +80 °C) to engine

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Hydrogen Storage Systems

• Hydrogen Adsorption

– MOFs and C Nanotubes• Surface Physisorption• Only saturate at 77K• H2 capacity α surface area• Very Low density materials

MOF: metal organic frame

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• Absorption into Metal Hydrides– Each Alloy system has a well characterized P vs T

system equilibrium.– AB5 and AB2 systems (ex. LaNi5H6 and Mg2NiH4)

are very heavy (1.5% to 3.4 % H2wt) but have good H2 density and low decomposition temperatures. (15KJmol -1 to 30 KJ mol-1)

– AlH3 (10.7% H2 wt ) decomposes below room T but requires immense pressures to hydride

– MgH2 (7.6% H2 wt)(covalent bond 76 kJ/mol) decomposes at temperatures close to 300 C and generates a lot of heat during hydrogenation.

Hydrogen Storage Systems

Alvaro Amieiro

Hydrogen Storage Systems

7.6

3.6

1.891.37

0

1

2

3

4

5

6

7

8

MgH2 Mg2NiH4 FeTiH2 LaNi5H6

Valu

e

% of weight that is hydrogen

H-atoms per cm3 (x 1022)

Very different hydrogen weight capacity have the same H2 volumetric density

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Hydrogen Storage Systems

• Organic Carriers

– Hydrogenation and dehydrogenation using a catalyst

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Hydrogen Storage Systems

• Complex Hydride Systems:– Borohydrides , Alanates and Amides– High gravimetric density– Regenerate with very high pressures– Catalysis Activation

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Catalysis and StructureCatalysis and Bond Destabilization

Mg destabilization

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MgH2 TEM Bright lines correspond to highly defected areas, this structure provides a network of crystal boundaries allowing hydrogen to diffuse through just a few nanometres of distance. Ni is assumed to deposit there

Magnesium Activation

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Solid Hydrogen Storage

• Cycle Materials Examples:

– Ni doped MgH2• 6%Wt H2 300 C 1-5 bar -75Kjmol

– TiCl3 doped NaAlH4• 230 C –35 to -45 kJ mol 5 %H2 wt 100bar

– Mg(NH2)2 + LiH2 (Catalysis not fully explored)• 200C 5 % H2 wt 100 bar (Leach ammonia in each cycle).

– Metal Organic Frames• 8%Wt at 77 K

Alvaro Amieiro

Solid Hydrogen Storage

• Examples one shot Materials:(Excluding CH4, NH3 and Chemical storage)

– NaBH4 Solutions– Millennium Cell technology provides wet H2 at low P– Borate expensive regeneration

– Mg oil slurry– Safe H2 technology: needs water to react– MgOH expensive regeneration

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H2 Storage Mass kg 1.9System Mass Kg 51Gravimetric density % H2 wt 3.7Volumetric density kgH2 / 100l 1.5Pressure bar 350

ExampleCompressed Hydrogen

350 Bar compressed H2 FC 2002

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H2 Storage Mass kg 7.3System Mass Kg 420Gravimetric density % H2 wt 1.9Volumetric density kgH2 / 100l 4.1

ExampleToyota 2005

Hydride + 350 bar tank-22 kJ mol-1

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Alvaro Amieiro

Hydrogen

“There is, therefore, nothing to fear. As long as the earth is inhabited it will supply the wants of its inhabitants, and there will be no want of either light or heat as long as the productions of the vegetable, mineral or animal kingdoms do not fail us. I believe, then, that when the deposits of coal are exhausted we shall heat and warm ourselves with water. Water will be the coal of the future."

Jules Verne The Mysterious Island

Chapter 33