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Metal hydride hydrogen storage tank for fuel cell utility vehicles
Mykhaylo Lototskyy, Ivan Tolj, Yevgeniy Klochko,
Moegamat Wafeeq Davids, Dana Swanepoel and
Vladimir Linkov
Fuel cell utility vehicles (incl. forklifts): Motivation
HyLIFT-DEMO Project Showcases Hydrogen Powered Fuel Cell Forklift Trucks at CeMAT logistics Fair May 2-6, Press release, Hannover, May 2, 2011
Hydrogen powered utility vehicles including material handling units with fuel cells combine the advantages of diesel / LPG and battery powered vehicles:• Constant power during the
entire shift;• Short refuelling time;• Zero emission electric
propulsion.
Lototskyy M. et al, Progress in Natural Science: Materials International 27 (2017) 3
Metal hydrides for heavy-duty FC powered utility vehicles incl. forklifts: Motivation
CGH2
•Approved technology, prototypes
available (Plug Power, H2Logics,
Proton Motor, PearlHydrogen);
•Fast refuelling;
•Safety and refuelling infrastructure
(filling H2 pressure ~350 bar);
•Space constrains;
•Additional counterbalance required
(forklift operation safety).
MH
H2
•Compact + heavy: intrinsic solution
of the counterbalance problem;
•Safety (lower standby H2 pressure);
•Simpler refuelling infrastructure
(filling H2 pressure <200 bar);
•Limitations of charge / discharge
rates (heat transfer issues).
Lototskyy M. et al, J. Power Sources, 316 (2016)Lototskyy M. et al, Progress in Natural Science: Materials International 27 (2017) 3
Background: MH hydrogen storageon-board fuel cell utility vehicles
• Low weight H2 storage capacity in MH is not drawback but advantage for this application. • Main challenge of conventional solutions (MH containers in a water tank) is still insufficient system
weight / too big size of the H2 storage system.
Prototype FC power module with integrated MH hydrogen storage (Hawaii Hydrogen Carriers)A. Narvaez. Presentation at US DOE Annual Merit Review Meeting, June 18, 2014, Project ST 095
➢ The MH tank (L=470 mm; W=700 mm; H=370 mm) stores ~2 kg (20 Nm3) H2 and has a weight ~500 kg when filled with water.
➢ For sufficient counter-balancing, all the components are assembled within rectangular metal casting body, and the most of its internal volume was occupied by the MH tank.
MH tank FC power moduleMine locomotive
FC powered mine locomotive with
integrated MH hydrogen storage (Vehicle Projects, Inc. & Anglo American
Platinum)P. Valicek, F. Fourie, 6th Int.
Platinum Conf, ‘Platinum–Metal for the Future’, The Southern
African Institute of Mining and Metallurgy, 2014
FC forklift with commercial FC power module and MH extension tank
AC Motors
DC / AC DC / DC
Battery
Auxiliaries
CGH2
+MH
H2 storage:
FC
MH H 2 purification
& compression
system H 2 ; P~50 bar
H2
HEAT
AIR
HP buffer
A
C
Cooling water
Steam Condensate
Pure H 2 P≤200 bar
80 VDC MAX 300 ADC
Forklift equipment
Power module components
Original developments
within this project
B
• In 2012-2015, HySA Systems integrated a MH H2 storage extension tank in a commercial GenDrive 1600-80CEA fuel cell power module (Plug Power Inc.) which was installed in a 3 tonne STILL electric forklift.
• Main performances (VDI-60):➢ Energy consumption 11.15 kWh/h.➢H2 fuel consumption 689 NL/kWh
(CGH2 31%, MH 69%).
• The prototype is in operation at Impala Platinum refineries in Springs, South Africa, since September 2015.
Lototskyy M. et al, Int. J. Hydrogen Energy, 41 (2016) 13831Lototskyy M. et al, J. Power Sources, 316 (2016)
MH extension tank: details
CGH2
11 Nm3 H2
@ 185 bar
T1
F1
CV1RECEPTACLE
V1 V2
MH
10 Nm3 H2
GenDrive 1000 160X-80CEA
Extension
FC
stack
➢Assembly of 20x MH containers connected in parallel to gas manifold.➢The assembly is submersed in external
water / glycol tank providing thermal control during the charge (cooling with ambient air) and discharge (heating from the FC stack).➢Dimensions 950 (L) x 120 (W) x 700 (H)
mm; weight ~200 kg.➢The tank is fitted in the forklift in the
space remaining vacant after the installation of the GenDrive power module.➢The total weight of the power module
and the extension tank is ~1800 kg that provides sufficient counter-balance for the safe forklift operation when lifting up to 3 tons.➢Only minor changes in high-pressure
H2 system of the GenDrive power module.➢21 Nm3 H2 total capacity at charge
pressure of 185 bar (for CGH2 only ~19 Nm3 @ 350 bar).
➢Next step: full integration of the MH H2 storage in fuel cell power module
HySA Systems power module for forklift: concept
Coolant Pump
DI Filter
Electronically
Controlled
Proportional Valve
Expansion
tank
Membrane
humidifier
Air
compressor
Air inlet
CGH2
MH
H2
H2 recirculation
pumpPressure regulator
Purge valve
-
+
Batt
ery
pack
CV
M
-
+
El.
outp
ut
A
V
Liq
uid
to l
iqu
id h
eat
exch
an
ger
Expansion
tankPump
Condenser
Anode
Cathode
F
Fuel supply
Air supply
FC cooling
MH heating/cooling
T
T
P
FP
P
PE
M F
C
110 c
ells
TT
T T
T T
BoP design• The BoP designed
around Ballard 9SSL / 75 Cell FC Stack.
• Main subsystems include:o The Cathode, Air
Subsystem;o The Anode, H2
Subsystem;o The Closed Circuit
Water cooling (stack) / heating (MH) subsystem.
• Challenges:o Component selection
constraints (availability, functionality & performance, size);
o Insufficient weight (ballast required);
o Alignment of the communication protocols
AIR MASS FLOW
METERAIR FILTER
A
N
O
D
E
T1
MANUAL SHUT-
OFF VALVE
P8C
O
O
L
A
N
T
M
M
AIR Scroll
COMPRESSOR
Cathode Heat
Exchanger
GAS – GAS
HUMIDIFIER
HYDROGEN
PURGE VALVE
HYDROGEN
RECIRCULATION
PUMP
O2 IN
CHECK
VALVE
H2 Line
H2 Supply
from Metal
HYDRIDE
Bed
SV
AIR STOICHIOMETRY = 1.8
H2
STOICHIOMETRY = 1.6
CHECK
VALVE
O2 OUT
H2 IN
From Cooling
System
Cooling
System Return
From Cooling
System
Cooling System
Return
Compressor
Motor Drive
H2 Buffer Tanks
MANUAL SHUT-
OFF VALVE
H2 Charge
Input
From Cooling
System
Cooling System
Return
CHECK
VALVELIQUID H2O
KNOCKOUT
LIQUID H2O
KNOCKOUT
H2O DRAIN
EXHAUST
MANUAL SHUT-
OFF VALVE
CHECK
VALVE
Metal
Hydride
Bed
Ba
llard
9S
SL
/ 75
Ce
ll Fu
el C
ell S
tack
H2
H2 Leak
detector
H2
H2
Concentration
Sensor
Pressure
Reducing Valve
AIR REFERENCE
PRESSURE
H2 OUT
P1
T2P2
T4P4
C
A
T
H
O
D
E
T3P3
T5P5
ISOLATION
VALVE
V-41
T6P6
P7
Air Reference
Pressure
V-43
ISOLATION
VALVE
RH
1
RH
2
Thermal Insulation
Thermal InsulationTherm Insu
Th
erm
al In
su
latio
n
Thermal InsulationThermal Insulation
H2
Air
Temperature control
Stack cooling / MH heating system• Stack cooling system is coupled with the
system of heating the MH tank
Patent ZA 2014/08640
Gas supply system
MH bed
• CGH2 buffer tank(s) provide stable H2 supply during the FC operation (H2 purging impulses)
Buffer tanks
Patent ZA 2014/08640
Fuel Cell Stack
H2 Leak Detector
System Controller
MH bed in a water tank
H2 Buffer Tanks
Anode Humidifyer
Air Intake Filter
Back Pressure Regulator
Water Trap
Cathode Air Compressor
Cathode Heat Exchanger
20kW Synchronous DC-DC Converter
Air Compressor Motor Drive
Cooling Radiator and FAN
8.4 kWh SLA Battery Bank
Hydrogen Recirculation Pump
HySA Systems power module for forklift: Specification and preliminary design
➢ Stack: closed cathode FC;➢ H2 storage: integrated MH
storage unit, 20 Nm3;➢ Battery bank: deep cycle
lead-acid, 8…10 kWh.
• Donor vehicle: STILL RX60-30L;
• Bus voltage (VDC): 80;• Output power (kW): ~15
(average), up to 30 (peak);
• Dimensions (mm): 840 (L) x 1010 (W) x 777 (H);
• Weight (kg): 1800…1900
• The total weight of the power module ~650kg. Addition of 1150 kg of a ballast is required to achieve the target weight.
• The size of the MH bed and water tank is almost 40% of the total space in the power module compartment. CGH2 buffer tanks do not fit in the available space
HySA Systems power module for forklift: Updated design
Fuel Cell Stack
MH Bed Encased in
Lead
Anode Humidifier
Air Intake Filter
Compressor Motor Drive
Cathode Air Compressor
8.4 kWh SLA Battery Bank
Cooling Radiator and fan
Cathode Heat Exchanger
System Control Electronics
H2 Recirculation Pump
H2 Reducer
MH hydrogen storage: material
Ti0.55Zr0.45(Cr,Mn,Fe,Ni)2 + 10 wt% La0.8Ce0.2Ni5
0 50 100 150 200
1
10
100
113 NL/kg (discharge @ 2 bar / -10 oC)
T= -10 oC
T=50 oC
T=30 oC
P(H
2)
[bar]
C [NL (H2) / kg]
T=10 oC
165 NL/kg (discharge @ 5 bar / 50 oC)
Charge @ 150 bar / 30 oC
0 50 100 150 200
1
10
100
176 NL/kg (discharge @ 2 bar / -10 oC)
T= -10 oC
T=50 oC
T=30 oC
P(H
2)
[bar]
C [NL (H2) / kg]
T=10 oC
198 NL/kg (discharge @ 5 bar / 50 oC)
Charge @ 150 bar / 30 oC
Ti0.85Zr0.15(Mn,V,Ni,Cr,Fe)2
Alloy 1: imported from CN (custom order)
Alloy 2: manufactured by HySA Systems
➢ C-14 AB2-type intermetallides; A=Ti+Zr, B=Mn+Cr+Ni+V+Fe
MH hydrogen storage: container
Alloy 1 (3.1 kg): 503 NL H2 Alloy 2 (2.9 kg): 624 NL H2
H2 charge performance
➢ Standard SS pipe with pressed-in perforated copper fins➢ Addition of expanded natural graphite to the MH powder
0 10 20 30 40 50 60
-10
0
10
20
30
40
50
60
70
H2Flow Rate
Pressure
Time (minutes)
H2F
low
Rate
(L/m
in),
Pre
ssure
(bars
)
20
22
24
26
28
30
32
34
36
38
40
Temperature Centre
Temperature Front
Temperature End
Tem
pera
ture
(oC
)
0 10 20 30 40 50 60
-10
0
10
20
30
40
50
60
70
H2Flow Rate
Pressure
Time (minutes)
H2F
low
Ra
te (
L/m
in),
Pre
ssu
re (
ba
rs)
20
22
24
26
28
30
32
34
36
38
40
Temperature Centre
Temperature Front
Temperature End
Te
mp
era
ture
(oC
)
➢ Rated up to 190 bar / 100 °C➢ External heating / cooling
Patent application WO 2015 189758 A1; patent ZA 2016/08250
MH hydrogen storage: tank (general layout)
• Main challenge of conventional solutions (MH containers in a water tank) is insufficient system weight.
• Suggested approach: assembly of cassettes each comprising several MH containers encased in lead.
✓ Patent application UK1806840.3; 26.04.2018
10 – metal hydride cassette: 11 – metal hydride container12 – gas manifold13 – external pipeline of the gas manifold14 – heating / cooling means15, 16 – external heating / cooling pipelines17 – filling body (lead alloy)18 – pre-assembly of the MH cassette
MH cassette MH cassette pre-assembly before lead encasing
11
1412
13
18
• Special procedure of lead encasing which allows to simultaneously activate the MH material in the MH cassette has been developed.
• When heated with running water to T=40–50 °C, the cassette releases more than 60% of its full capacity (~2.5 Nm3) at the H2 flow rate of 25 NL/min.
• 8 MH cassettes have been manufactured and installed in the frame of forklift power module to form, together with 9L buffer cylinder, a hydrogen storage tank.
• The tank is characterised by H2 storage capacity above 20 Nm3 (1.8 kg) and has a weight ~1.2 tonnes that allows to provide counterbalancing weight (1850 kg for the whole power module within the space constrains) necessary for the safe operation of 3 tonne forklift.
• The tank can provide >2 hour long H2 supply to the FC stack operated at 11 kWe (H2 flow rate of 120 NL/min).
• The refuelling time of the MH tank (T=15–20 °C, P(H2)=150–180 bar) is about 15–20 minutes.
Lead encasing
Left: two ready-to-use MH cassettes. Right: MH tank for forklift power module comprising 8 MH cassettes
0 20 40 60 80 100 120
0
10
20
30
40
50
H2 flow rate [NL/min]
H2 pressure [bar]
T(MH) [oC]
T(in) [oC]T
, P
, F
R
Time [min]0 20 40 60 80 100 120
0
10
20
30
40
50
60
H2 pressure [bar]
H2 flow rate [NL/min]
T(MH) [oC]
T, P
, F
R
Time [min]
T(in) [oC]
MH hydrogen storage: tank
H2 charge (left) and discharge (right) performance of the MH cassette; water flow (T=T(in)) ~4 L/min
FC power module: Assembling on-board prototype
• Optimised BoP configuration (FC stack + SLA battery pack + supercapacitors) and control algorithms.
• Integration of the heating circuit of the MH tank with the stack cooling system.
• Optimisation of the fuel supply and purging strategy to reduce H2
consumption and increase efficiency is in progress.
MH tank
CGH2 buffer
Conclusions• The use of fuel cells in heavy duty utility vehicles, including material handling
units / forklifts or underground mining vehicles, has a number of advantages over similar diesel / LPG or battery-driven vehicles.
• Most of vehicular FC power systems have utilised compressed H2 stored in gas cylinders at pressures up to 350 bar. This solution, however, results in too light weight of the FC power modules for the utility vehicles which require additional ballast for a proper counterbalancing to provide vehicle stability.
• Intermetallic hydrides with H storage capacities below 2 wt% can provide compact H2 storage simultaneously serving as a ballast. However, further weight increase is necessary for the sufficient counterbalancing within strict space constrains.
• New engineering solution of a MH hydrogen storage tank for FC utility vehicles which combines compactness, adjustable high weight, as well as good dynamics of hydrogen charge / discharge has been developed.
• The developed MH tank comprises plurality of MH cassettes made as assemblies of externally heated / cooled MH containers staggered together with the heating / cooling tubes and encased in molten lead followed by the solidification of the latter.
• The MH tank has been successfully integrated in a prototype fuel cell power module for electric forklift.
Acknowledgements
• Impala Platinum Limited – co-funder;
• Department of Science and Technology (DST) via HySA Programme (projects KP3-S02 and KP3-S03) – co-funder;
• European Commission, Grant Agreement number: 778307 – HYDRIDE4MOBILITY –H2020-MSCA-RISE-2017 “HYDRIDE4MOBILITY” – support of international collaboration.
• Hot Platinum (Pty) Ltd – integration of the power module
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