Development and testing of the fuel cell power module for ...
Transcript of Development and testing of the fuel cell power module for ...
Development and testing of the fuel cell power module for 3-ton electric
forklift LOTOTSKYY, Mykhaylo; PARSONS, Adrian; TOLJ, Ivan;
KLOCHKO, Yevgeniy; KHAN, Irshad; BREY, Ali;
SHENKER, Maurice; SMITH, Fahmida; SITA, Cordellia;
LINKOV, Vladimir
Background
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 metal hydride (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.
• Main malfunctions identified were mainly related to Li-ion battery.
[1] Lototskyy, M.V. et al., Metal hydride hydrogen storage and supply systems for electric forklift with low-temperature protonexchange membrane fuel cell power module Int. J. Hydrogen Energy, 41 (2016) 13831-13842. [2] Lototskyy, M.V. et al., Performance of electric forklift with low-temperature polymer exchange membrane fuel cell power module and metal hydride hydrogen storage extension tank J. Power Sources, 316 (2016) 239-250
Specification and concept 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
• 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
➢ Stack: closed cathode FC;➢ H2 storage: integrated MH
storage unit, 20 Nm3;➢ Battery bank: deep cycle
lead-acid, 8…10 kWh.
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
Gas supply systems
MH bed
MH hydrogen storage• Main challenge of conventional solution (MH
containers in a water tank) is insufficient system weight. Suggested approach: assembly of cassettes each comprising several MH containers encased in lead.
• 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 tonnesthat allows to provide counterbalancing weight (1850 kg for the whole power module within the space constrains) necessary for the safe operation of 3 tonneforklift.
• 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.
✓ Patent application filed: UK1806840.3; 26.04.2018
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
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H2 pressure [bar]
H2 flow rate [NL/min]
T(MH) [oC]
T, P
, F
R
Time [min]
T(in) [oC]
H2 charge (left) and discharge (right) performance of the MH cassette; water flow ~4 L/min
System prototyping• All BoP components have been identified,
procured and assembled off-board;• Most of the components are standard, from
automotive industry;• Main challenge – the communication
interface link between the various components;
• The PLC supplier has developed special firmware for the control system to enable it to communicate with the components via CAN2.0 protocol;
• The CAN implementation has been completed, and all of the BoP components requiring CAN bus communication have been integrated into a network controlled by an industrial PLC system;
• Original cell voltage monitoring system has been developed;
• The switching Load Bank Resistors have been introduced to emulate various operating conditions.
➢ The off-board test results will be presented below.
HMI screenshots
Electrical layout (1)
• Initial configuration: auxiliary DC/DC converters are connected to 84 (7 x 12) V battery terminals
Electrical layout (1): test results
0 500 1000 1500 2000
0
50
100
150
200
250
300
350
H2 f
low
, C
urr
ent,
Voltage
time [seconds]
Battery voltage [V]
FC current [A]
H2 flow [NL/min]
0
2000
4000
6000
8000
10000
12000
14000
Sta
ck P
ow
er
[W]
Stack power [W]
1700 1800 1900 200060
70
80
90
time
Voltag
e• At maximum stack
power, the battery voltage drops below the minimum voltage required for the operation of the auxiliary DC/DC’s resulting in the stack shut-down.
• Origin – too high internal resistance of the lead-acid battery.
➢ Electrical layout should be modified.
Electrical layout (2)
• Revised configuration: auxiliary DC/DC converters were removed (auxiliaries connected directly to 24 V and 48 V branches of the battery bank); one battery was removed from the bank.
Electrical layout (2): test results
• No battery voltage drop was observed.
• Unstable operation when the load power (peaks) exceeds MAX stack power.
• Heating-up the battery during the operation at high load power (incl. peak load).
➢ Electrical layout should be further modified
0 1000 2000 3000 4000 5000 6000
0
50
100
150
200
250
300
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400
450
500
Cu
rre
nt,
Volta
ge
time [seconds]
Battery voltage [V]
FC current [A]
0
1600
3200
4800
6400
8000
9600
11200
12800
14400
16000
BoP power [W]
Pow
er
Stack power [W]
Electrical layout (3)
• Revised configuration: To compensate for the peak power draw of the load, an ultra capacitor was added to the system in parallel with the Lead Acid battery
Electrical layout (3): test results• Stable operation at peak power up to 30
kW.• The battery contribution to the load power
during the peaks decreases in ~2 times due to the contribution of ultra capacitor.
• The battery is not heated-up.• The battery depth of discharge is also
significantly lower than for the layout (2).• Average fuel cell power required is ~8 kW.
✓ Average energy consumption ~ 9.0 kWh/h✓ Average load power ~ 8.1 kW✓ Average BoP power ~ 900 W✓ Average H2 consumption ~ 900 NL/kWh✓ Estimated system efficiency ~30%
(related to HHV)
3000 3200 3400 3600 3800 4000
0
20
40
60
80
100
Ba
ttery
volta
ge
[V
]
time [seconds]
Battery voltage
0
5000
10000
15000
20000
25000
30000
35000
40000
Battery power Load power
BoP power
Po
we
r [W
] Stack power
0 1000 2000 3000 4000
0
5000
10000
15000
20000
25000
30000
35000
Po
we
r [W
]
time [seconds]
Load power
Stack power
Assembling on-board prototype• Based on the test results
presented above, the BoPconfiguration has been updated.
• All BoP parts for the on-board prototype have been procured.
• Assembling of the prototype power module is in progress.
• The control algorithm is being finalised towards:o Automatic switch of the
stack to a) Standby, b) Run and c) Shutdown modes depending on the system status;
o Optimisation of the fuel supply and purging strategy to reduce H2 consumption and increase efficiency.
Conclusions• General layout of fuel cell power module for 3 tonne electric forklift
with integrated MH hydrogen storage system has been elaborated.• The module fits in the space and weight constrains of the application
and comprises the following components: o 14.5 kW closed cathode PEMFC stack (Ballard);o Lead-acid battery bank;o Advanced metal hydride hydrogen storage tank (20 Nm3 H2).
• Test bench prototype of the power module has been built and tested in various hardware configurations.
• The optimal electrical system layout providing it stable operation at presence of peak loads (up to 30 kW) has been identified including:o Powering of auxiliary system components directly from the
sections of the battery bank;o Sizing of the battery bank;o Introducing ultra-capacitors.
• Further increase of the overall system efficiency by the optimisation of purging strategy, together with the assembling of the on-board prototype, is underway.
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.