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Impact of Battery Characteristics on Fuel EEconomy
AABCAABCMarch 2008
Aymeric Rousseau, Neeraj Shidore, y , j ,Richard Carlson, Dominik Karbowski
Argonne National Laboratory
Sponsored by Lee SlezakSponsored by Lee Slezak
This presentation does not contain any proprietary, confidential, or otherwise restricted information
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Outline
Process Description
Optimum Control Strategy
Impact of Available Energy
Impact of Peak Power
Impact of Temperature
– Battery in an emulated vehicle
– On‐Road vehicle testingg
Conclusions
2
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Battery Characteristics Evaluation ProcessBattery Hardware
Vehicle Simulation
tJtSOCtP 11
Simulation
4WD Test Facility
tSOCtP nm ,
tJtSOCtP '0,000 ,1',1
tJtSOCtP MMMM ',' ,1,1
tU 0
tU M
TX 0X. . .
.
.
.
Emulated Vehicle
Global Optimization
Natural Cold Test Chamber
100% Modeling 100% Hardware
Energy & Power Temperature Effects
3
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Global Optimization Allows Fair Comparison of Component Sizes and TechnologiesComponent Sizes and Technologies Knowing the drive cycle, the algorithm defines what would be the optimum component operating points to minimize fuelthe optimum component operating points to minimize fuel consumed. Algorithm adapts itself to all parameters influencing control: Drive cycle Distance Component size (energy, power) and technology…p ( gy, p ) gy
Impact of Energy Impact of Power
5 different AER (UDDS)Power remains constant
5 different powerEnergy remains constant
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PSAT Vehicle Assumptions2.3L Ford
Duratec (100kW)5 SpdAMT
Ratio3.8
P195_60_R15Radius=0.317
Cd = 0.315FA = 2.244 m2
S ll SUV
Li-ionJCS
800W UQM75kW
Small SUVAll Electric Range of 5, 10, 20, 30 and 40 miles on UDDS
JCS41 Ah
72 cells61 kW (10s)
6 4 kWh usable
75kW Peak
5
6.4 kWh usable
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Energy Sizing Impacts Fuel Displacement when Distance Traveled > AERwhen Distance Traveled > AER Distance Traveled AER– Decrease in fuel consumption is proportional to increase in AER
1 5 L/100 km differen e bet een UDDS and LA92
6
7
100k
m)
Driven Distance: 10 miles
6
7
100k
m)
Driven Distance: 10 miles
300
350
(Wh/
km)
Driven Distance: 40 miles
Wh/km (UDDS)Wh/km (HWFET)
300
350
(Wh/
km)
Driven Distance: 40 miles
Wh/km (UDDS)Wh/km (HWFET)
– 1.5 L/100 km difference between UDDS and LA92
3
4
5
Cons
umpt
ion
(L/1
L/100km (UDDS)3
4
5
Cons
umpt
ion
(L/1
L/100km (UDDS) 150
200
250
Con
sum
ptio
n (Wh/km (HWFET)
Wh/km (LA92)
150
200
250
Con
sum
ptio
n (Wh/km (HWFET)
Wh/km (LA92)
0
1
2
Min
imal
Fue
l C L/100km (HWFET)L/100km (LA92)
0
1
2
Min
imal
Fue
l C L/100km (HWFET)L/100km (LA92)
0
50
100
Elec
tric
Ene
rgy
0
50
100
Elec
tric
Ene
rgy
6
05 10 20 30 40
AER (miles)
05 10 20 30 40
AER (miles)5 10 20 30 405 10 20 30 40
0
AER (miles)5 10 20 30 405 10 20 30 40
0
AER (miles)
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Energy Impact on Battery use depends on Trip Distanceon Trip Distance
Distance Traveled AER,
Blended mode,
120Driven Distance: 10 miles
120Driven Distance: 10 miles
120Driven Distance: 40 miles
120Driven Distance: 40 miles
Similar RMS current Lower RMS current
80
100
(A) 80
100
(A)
80
100
(A)
UDDSHWFETLA92
80
100
(A)
UDDSHWFETLA92
40
60
RM
S cu
rren
t
40
60
RM
S cu
rren
t
40
60R
MS
curr
ent
40
60R
MS
curr
ent
5 10 20 30 400
20UDDSHWFETLA92
5 10 20 30 400
20UDDSHWFETLA92
0
20
R
0
20
R
7
5 10 20 30 40AER (miles)
5 10 20 30 40AER (miles)
5 10 20 30 40AER (miles)
5 10 20 30 40AER (miles)
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Peak Battery Power Has Little Influence on Fuel Consumptionon Fuel Consumption Lower fuel consumption for lower power levels due to decrease in regenerative
braking energy
5
00km
)
250
Wh/
km)
Driven Distance: 10 miles5
00km
)
250
Wh/
km)
Driven Distance: 10 miles
g gy
3
4
mpt
ion
(L/1
0
150
200
umpt
ion
(W
L/100km (UDDS)
L/100k (HWFET)
Wh/km (UDDS)
Wh/k (HWFET)
3
4
mpt
ion
(L/1
0
150
200
umpt
ion
(W
L/100km (UDDS)
L/100k (HWFET)
Wh/km (UDDS)
Wh/k (HWFET)
2
Fuel
Con
sum
100
Ener
gy C
onsL/100km (HWFET)L/100km (LA92)
Wh/km (HWFET)Wh/km (LA92)
2
Fuel
Con
sum
100
Ener
gy C
onsL/100km (HWFET)L/100km (LA92)
Wh/km (HWFET)Wh/km (LA92)
0
1
Min
imal
0.6 0.8 1 1.2 1.40
50
Elec
tric
E
0
1
Min
imal
0.6 0.8 1 1.2 1.40
50
Elec
tric
E
8
0.6 0.8 1 1.2 1.4Power Scaling Ratio
0.6 0.8 1 1.2 1.4Power Scaling Ratio
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Lower Power Leads to Higher Time Spent at High CurrentsSpent at High Currents
0.5
e
Driven Distance: 10 miles0.5
e
Driven Distance: 10 miles0.5e
Driven Distance: 20 miles0.5e
Driven Distance: 20 miles
0 3
0.4
the
Red
Zon
e
UDDSHWFETLA92
0 3
0.4
the
Red
Zon
e
UDDSHWFETLA92
0 3
0.4
n th
e R
ed Z
on UDDSHWFETLA92
0 3
0.4
n th
e R
ed Z
on UDDSHWFETLA92
0.2
0.3
age
of C
urri
n
0.2
0.3
age
of C
urri
n
0.2
0.3
tage
of C
urri
n
0.2
0.3
tage
of C
urri
n0.6 0.8 1 1.2 1.4
0
0.1
Perc
enta
0.6 0.8 1 1.2 1.40
0.1
Perc
enta
0.6 0.8 1 1.2 1.40
0.1
Perc
ent
P S li R ti0.6 0.8 1 1.2 1.4
0
0.1
Perc
ent
P S li R tiPower Scaling RatioPower Scaling Ratio Power Scaling RatioPower Scaling Ratio
Battery current is considered in the “red zone” when it exceeds the ti i l ( 150 A f f )
9
continuous maximum value (>150 Amps for reference)
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Evaluation of Battery In An Emulated Vehicle SystemVehicle System
JCS VL41M260V, 41Ah
10
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AER Decreases with Temperature
100
Initial Temperature 20 CVehicle Speed (m/s)
80
90
e speed
Initial Temperature 20 C Initial Temperature 0 CInitial Temperature -7 C
60
70
rge, Veh
icle
40
50
ate of Char
0 500 1000 1500 2000 2500 3000 350020
30Sta
11
Time (seconds)
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AER Drops by 13% at -7C17 5
17.3417
17.5
16.5
DDS (m
iles)
9% Decrease
13% Decrease
15.74
15.5
16
Range on
UD
15 0615
15.5
EV R
15.06
14.5
‐10 ‐5 0 5 10 15 20 25
Initial Mod le Temperat re (De ree C)
12
Initial Module Temperature (Degree C)
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AER Decrease Mostly Due to Regen Energy and Other Losses than Internal ResistanceOther Losses than Internal Resistance
Initial Temperature Battery kWh ΔkWh
Battery Losses at Lower Temperature
e pe u e
20 6.2 0
0 5.6 0.53
–7 5.5 0.73
SourceInitial
TemperatureΔWh compared to Wh
delivered at 20°CΔRegen Energy as
% of ΔWhΔI2Rt as % of
ΔWhΔOther Losses as
% of ΔW
0C 530 34% 8% 58%0C 530 34% 8% 58%
–7C 730 34% 12% 54%
13
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Battery Temperature Impact During On Road TestingOn-Road Testing
315 VDC Li-Ion
20kW DC/DC
Hymotion/A123 7kWh Pack
Converter
Escape NiMH 340 VDC Battery Pack
Escape Powertrain
Inverter
Escape Powertrain
Hymotion Escape PHEVHymotion Escape PHEV7 kWh Li-ion (A123)
14
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Fuel Economy Still Increases After 20 miles!miles!
Battery Temperature Still Increasing After
60 i t !
15
Entire Vehicle Was Cold 60 minutes!
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Higher Li-ion Temperature Leads to Increased Battery Usage and Lower Fuel ConsumptionBattery Usage and Lower Fuel Consumption
16
Both Batteries Warmed – Cold Vehicle
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Most of the Fuel Consumption Increase Due to Cold BatteryIncrease Due to Cold Battery
17
Percent increase in fuel consumption over steady-state fuel consumption –5°C
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Impact of Cold Battery Mostly Due to Discharge EnergyDischarge Energy
18
Regenerative Braking Difference only Due to NiMH
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Conclusion When the distance driven is higher than the AER, the optimal
control is blended. As the engine is operated at high power, the battery RMS current is lowered.battery RMS current is lowered.
The available battery energy has significant impact on fuel consumption.
The peak battery power affects fuel consumption mostly with regard to regenerative braking energy.
The RMS battery current is influenced by several factors: The RMS battery current is influenced by several factors:
– Blended control lowers Irms
– Irms increases with electrical consumptionIrms increases with electrical consumption
Lower power batteries operate more often above their continuous current limits
19
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Conclusion (cont’d)
Testing a battery in an emulated vehicle, the AER decreases by 9% at 0°C and by 13% at ‐7°C, as compared with 20°C conditions. Decreases in regenerative braking energy combined with “other losses” explain the changes.
For the PHEV conversion tested the on road test results For the PHEV conversion tested, the on‐road test results demonstrated that:
– The powertrain warm‐up causes most of the losses during the early stage of the drive cycle (10 minutes)
– The battery pack then accounts for most of the changes in fuel consumptionconsumption
At cold temperatures, control limitations, especially discharging energy, are the main reason for lower fuel economy.
20
n1
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Slide 20
n1 First bullet on this slide : Decreses in inherent battery capacity and regen energy explain the chagnes. ( There are the major contributors).nshidore, 4/27/2008