Performance Testing of Lithium-ion Batteries of Various Chemistries
for EV and PHEV Applications
Andrew Burke
University of California-Davis
Institute of Transportation Studies
2009 ZEV Symposium
Sacramento, California
September 22, 2009
Outline of the presentation
1.
2.
3.
4.
5.
6.
7.
Introduction
Batteries tested
Selected test data for lithium-ion cells
Summaries of battery characteristics
Determination of power capability
Test data for fast charging of cells
Summary and conclusions
Energy storage requirements for various electric and hybrid passenger cars
(Prius size vehicles)
Type of
hybrid
driveline
Electric
vehicle EV
Plug-in
Charge
sustaining
Microhybrid
System
voltage
V
Useable energy
storage
Maximum pulse
power at 90%
efficiency kW
Cycle life
(number of
cycles)
300-400
25-35 kWh
50-120
3000-4000
300-400
6-12 kWh
50-70
2500-3500
150-200
100-150 Wh
25-35
300K-500K
45
30-50 Wh
5-10
300K-500K
Useable
depth-ofdischarge
deep
60-80%
deep
60-80%
Shallow
5-10%
Shallow
5-10%
Battery sizing and power density for plug-in hybrid vehicles for various
all-electric range and electric motor power (mid-size passenger car)
Electric Engine Battery Battery
Range motor
power
kWh
kWh** Battery Battery
P/E
miles
kW
kW
*needed stored
kg*** kW/kg
10
50
100
2.52
3.6
30
1.66
13.8
15
55
100
3.78
5.4
45
1.22
10.2
20
60
75
5.04
7.2
60
1.0
8.3
30
75
60
7.56
10.8
90
.83
6.9
40
100
50
10.1
14.4
120
.83
6.9
* Vehicle energy useage from the battery: 250 Wh/mi
** Useable state-of-charge for batteries: 70%, weights shown are for cells only
*** battery energy density 120Wh/kg
Emerging Battery Technologies
Graphite/NiCo and Mn spinel
Iron phosphate (positive)
Lithium titanate oxide (negative)
Cylindrical vs. prismatic cells
Developers/batteries available for testing
Battery
developer
Battery type
Cells/modules tested
Iron phosphate
2.1Ah
cylindrical
GAIA
LiMnO2
Altairnano
EIG
Lithium
titanate
LiMnO2
Iron phosphate
Valence
Iron phosphate
K2 Energy
Solutions
Kokam
Iron phosphate
LiMnO2
Interdel
LiMnO2
Quallion
Panasonic
LiMnO2
LiMnO2
7.5Ah, 40Ah cells
cylindrical
11 Ah, 50Ah, 3.8Ah cells
16V and 24V modules
18Ah, 74V module
11 and 15Ah, 74V module
Prismatic
1.35 Ah cylindrical cells
12V module
3 Ah cylindrical
cells
8 and 30Ah
Prismatic
Cells expected
prismatic
Cylindrical cells
1-3 Ah
Cylindrical 2.5-3.0Ah
A123
42 Ah
EIG cells
7.5Ah
GAIA Cells
Altairnano cells
Selected cylindrical Lithium cells
K2 solut.
Quallion
Valence
ThunderSky/China cell
99 Wh/kg at C/2
180 W/kg at 90% eff.
R= .65 mOhm
Lithium iron Phosphate 260 Ah
PHET 12V module
Iron Phosphate
12V, 33 Ah, 8.64 kg
28P,4S; 1.2 Ah cells
12V Module from Valence
Iron Phosphate
12.8V, 40 Ah, 6.3 kg, 84 Wh/kg
EIG 72V Modules NiCOMnO2 and Iron phosphate
Modules include cooling fans and battery management hardware/software
24V Module of the Alairnano 50Ah cells
(Lithium Titanate Oxide)
Test procedures and approach
Start with cells, then modules, then packs
Constant current and then constant power
Pulse tests at various SOC
Testing with battery management/monitoring units
Pulse power cycle (driving simulation) tests – CD, CS
Life cycle tests
Fast charging
Kokam High Power Cells (graphite/NiCoMnO2)
Constant current discharges
Current (A)
15
30
60
100
150
4.1V to 3.2V
Time (sec)
Ah
7417
30.9
3611
30.1
1728
28.8
976
27.1
603
25.1
Charge at 31A to 4.2V and taper to 1.5A
Constant power discharges
4.1V to 3.2V
Power (W)
Time (sec)
43
9806
82
4835
162
2355
242
1509
321
1097
402
854
482
674
Cell weight 787 g
Wh
117.1
110.1
106.0
101.4
97.8
95.4
90.2
Wh/kg
148.8
139.8
137.7
128.9
124.3
121.2
114.6
nC
.485
1.0
2.08
3.69
5.97
W/kg
55
104
206
308
408
511
612
Pulse test data for the 31Ah Kokam Cell
Cell resistance based on pulse tests 5 sec pulses, V at 2 sec
State-of-charge
80%
Voc = 3.94
60%
Voc = 3.75
40%
Voc = 3.64
Current (A)
150A disch
200A disch
310A disch
50A charge
100A charge
150A charge
Resistance (mOhm)
1.6
1.6
1.55
1.6
1.6
1.53
150A disch
200A disch
310A disch
50A charge
100A charge
150A charge
1.53
1.5
1.45
1.6
1.5
1.53
150A disch
200A disch
310A disch
50A charge
1.53
1.5
1.42
1.6
Test data for the 12V Valence module (iron phosphate)
Constant current tests*
Current A
Time sec
Ah
C/n
20
7054
39.2
C/1.96
40
3525
39.2
C/.98
60
2379
39.6
C/.66
80
1782
39.6
C/.5
100
1441
40
C/.4
* module consists of 30-1.35 cells in parallel and 4 in series
charged at 20A to 14.6V and tapered to 2A .
discharged to a cut-off voltage of 10V
Constant power tests
Power W
W/kg *
300
47
600
94
900
142
1200
189
* module weight 6.36 kg
Time sec
6025
2949
1929
473
Wh
502
492
482
473
Pulse tests *
Resistance mOhm
Current A
discharge
charge
100
9.3
9.3
150
9.2
9.3
200
9.3
9.3
* 5 sec pulses, voltage read at 2 sec to calculate
the resistance; SOC= 62%
Wh/kg
79
77
76
74
Test results for the 100 Ah Tenergy cell from China
Cell is rated at 100Ah, weighs 3.5 kg, and is the iron phosphate
chemistry
Constant current
I(A)
25
50
100
150
Ah
106.1
103.1
100.9
100.0
Constant power
W
182
352
W/kg
52
100
sec
6009
2967
Wh
304
290
Wh/kg
87
83
max T
29
41
Pulse tests
I(A)
300
300
400
mohms
1.5
5 sec discharge pulse
1.4
5 sec charge pulse
1.5
5 sec discharge pulse
Calculation of the peak pulse power
90% efficiency at SOC=50%
P = .1x.90x (3.28)2 /R
P = .1x.90x (10.76) /.0015 = 645 W,
184 W/kg (low power cell)
delta T
5
15
Test data for the EIG graphite/ NiCoMnO2 cell
Weight
4.2V-3.0V
.45kg
Power (W)
W/kg
Time (sec)
Wh
50
111
4560
63.0
90
200
2486
62.1
120
267
1906
63.5
Current (A)
20
40
60
Time (sec)
3242
1602
1065
Ah
18
17.8
17.8
Crate
1.1
2.2
3.3
Resistance
3 sec pulses
mOhm
100A
3.2
2.9
3.6
250A
3.12
3.12
3.3
(W/kg)90%eff.
1069
895
718
SOC
100%
50 %
20%
Voc
4.11
3.67
3.52
Wh/kg
140.7
138.0
141
Pulse characteristics of the CO20Acell at 250A at various states-of-charge
Voc
4.12
3.98
3.88
3.78
3.72
3.67
3.63
3.59
3.54/100A
3.48/100A
DOD %
0
10
20
30
40
50
60
70
80
90
V2 sec
3.33
3.24
3.14
3.06
2.98
2.90
2.84
2.74
3.18
2.96
Effic. %
80.8
81.4
80.9
81.0
80.1
79.0
78.2
76.3
89.8
85.1
R mOhm
3.16
2.96
2.96
2.88
2.96
3.08
3.16
3.4
3.6
5.2
Power W
833
810
785
765
745
725
710
685
318
296
W/kg
1850
1800
1744
1700
1655
1611
1578
1522
706
658
Test data for the 15 Ah EIG iron phosphate cell
Iron
Phosphate
FO 15A
Power (W)
62
102
202
302
401
Weight .424kg
W/kg
142
240
476
712
945
3.65-2.0V
Time (sec)
2854
1694
803
519
374
Wh
49.5
48.0
45.1
43.5
41.7
Wh/kg
117
113
106
103
98
Current (A)
Time (sec)
Ah
Crate
Resistance
mOhm
15
30
100
200
300
3776
1847
548
272
177
15.7
15.4
15.2
15.1
14.8
.95
1.95
6.6
13.2
20.3
2.5
Test data for the Altairnano 11Ah lithium titanate oxide cell
Constant current test data (2.8-1.5V)
I(A)
10
20
50
100
150
200
nC
.8
1.7
4.5
9.2
15.3
---
Time (sec)
4244
2133
806
393
235
116
Resistance
mOhm
--2.2
2.1
---
Ah
11.8
11.9
11.2
10.9
9.8
6.4
Resistance based on 5 sec pulse tests
Constant power test data (2.8-1.5V)
Power
W/kg
W
30
88
50
147
70
206
100
294
150
441
170
500
260
764
340
1000
Mass: .34 kg
Time
sec
2904
1730
1243
853
521
457
255
103
nC
1.2
2.1
2.9
4.2
6.9
7.9
14
35.0
Wh
24.2
24.0
24.2
23.7
21.7
21.6
18.4
9.7
Wh/kg
71.2
70.7
71.0
69.7
63.8
63.5
54.2
28.6
Performance characteristics of lithium-ion batteries
Battery
Developer/
Cell type
Kokam
prismatic
Saft
Cylind.
GAIA
Cylind.
A123
Cylind.
Altairnano
prismatic
Altairnano
prismatic
Quallion
Cylind.
Quallion
Cylind.
EIG
prismatic
EIG
prismatic
Panasonic
EV
prismatic
Electrode
chemistry
Voltage
range
Ah
Resist.
mOhm
140
W/kg
90%
effic.*
1220
Wh/kg
Wgt.
(kg)
.787
Density
gm/cm3
2.4
Graphite/
NiCoMnO2
Graphite/
NiCoAl
Graphite/
NiCoMnO2
Graphite/Iron
Phosph.
LiTiO/
NiMnO2
LiTiO/
NiMnO2
Graphite/
NiCo
Graphite/
NiCo
Graphite/
NiCoMnO2
Graphite/Iron
Phosph.
Ni Metal
hydride
4.1-3.2
30
1.5
4.0-2.5
6.5
3.2
63
1225
.35
2.1
4.1-2.5
.48
3.6
12
96
78
90
2063
1.53
3.22
3.6-2.0
40
7
2.2
1393
.07
2.2
2.8-1.5
11
2.2
70
990
.34
1.83
2.8-1.5
3.8
1.15
35
2460
.26
1.91
4.2-2.7
1.8
60
144
577
.043
2.6
4.2-2.7
2.3
72
170
445
.047
2.8
4.2-3.0
18
3.1
140
1122
.45
----
3.652.0
7.2-5.4
15
2.5
113
1100
.42
---
6.5
11.4
46
395
1.04
1.8
* power density at full charge P= Eff.*(1-Eff.) Voc2 /R
Performance characteristics of various high power batteries
Battery
manufact.
Electrode
chemistry
Voltage
range Ah
Saft
Graphite/
NiCo
Graphite/
NiCo
Graphite/
Iron
Phosph.
Graphite/
Iron
Phosph.
LiTiO/
NiCo
LiTiO/
NiCo
Graphite/
NiCo
Ni Metal
hydride
4.0-2.5
GAIA
A123
EIG
Altairnano
Altairnano
Kokam
Panasonic
EV
Resist.
mOhm
63
W/kg
95%
effic.
645
Wh/kg
Wgt.
(kg)
.35
Density
gm/cm3
2.1
6.5
3.2
4.1-2.5
40
.48
96
1086
1.53
3.22
3.6-2.0
2.2
12
90
733
.07
2.2
3.6-2.0
15
2.5
113
580
.42
---
2.8-1.5
11
2.2
70
521
.34
1.83
2.8-1.5
3.8
1.15
35
1300
.26
1.91
4.1-3.2
31
1.5
140
644
.787
2.4
7.2-5.4
6.5
11.4
46
208
1.04
1.8
Characteristics of lithium-ion batteries using various chemistries
Chemistry
Anode/cathode
Graphite/
NiCoMnO2
Graphite/
Mn spinel
Graphite/
NiCoAlO2
Graphite/
iron
phosphate
Lithium
titanate/
Mn spinel
Cell
voltage
Max/nom.
Ah/gm
Anode/cathode
Energy
density
Wh/kg
Cycle life
(deep)
Thermal
stability
4.2/3.6
.36/.18
100-170
2000-3000
4.0/3.6
.36/.11
100-120
1000
4.2/3.6
.36/.18
100-150
2000-3000
fairly
stable
fairly
stable
least
stable
3.65/ 3.25
.36/.16
90-115
>3000
Stable
>5000
most
stable
2.8/2.4
.18/.11
60-75
Determination of the cell/battery power capability
from the test data - a matter of data interpretation
and not measurement
Calculation the pulse power characteristics of batteries
using the USABC and energy efficiency methods
USABC method
PABC = Vmin (Vnom.OC – Vmin)/R
PABC = Vmax (Vmax - Vnom.OC )/R
discharge
charge
VnomOC is the open-circuit voltage at a mid-range SOC
Vmin is the minimum voltage at which the battery is to be operated in discharge
Vmax is the maximum voltage at which the battery is to be operated in charge (regen)
R is the effective pulse resistance of the battery
Pulse efficiency method
PEF = EF(1-EF) V 2nomOC / R both charge and discharge pulses
Matched impedance power method
PMI = Voc2 /R
Differences in the maximum peak power predicted by the USABC and
the EF methods
discharge
PEF /PABC = EF(1-EF)/ [(Vmim/VnomOC)(1-Vmin /VnomOC)]
charge
PEF /PABC = [(VnomOC/ Vmax,ch)2/ (1- VnomOC/ Vmax,ch)] EF(1-EF)
Example: Iron Phosphate
VnomOC = 3.2, Vmin = 2, Vmax = 4.0
Efficiency
.95
.90
.85
.80
.75
.70
EF(1-EF)
.0475
.09
.1275
.16
.1875
.21
Discharge
PEF/ PABC
.20
.38
.54
.68
.80
.90
charge
PEF/ PABC
.15
.29
.41
.51
.60
.67
Example: Nickel Cobalt
VnomOC = 3.7, Vmin = 2.5, Vmax = 4.3
Efficiency
.95
.90
.85
.80
.75
.70
EF(1-EF)
.0475
.09
.1275
.16
.1875
.21
Discharge
PEF/ PABC
.22
.41
.58
.73
.86
.96
charge
PEF/ PABC
.25
.48
.68
.85
1.0
.1.0
Comparisons of the Power Capability of two battery
chemistries using various methods
Approach
Pulse
efficiency (%)
95
90
80
70
USABC
Matched
impedance
Kokam 31 Ah
NiCo
W/kg*
EIG 15Ah
Iron Phosphate
W/kg*
551
1044
1856
2513
458
866
1540
2021
2541
2264
2879
2415
R=1.5 mOhm
R= 2.5 mOhm
* power densities at 50% SOC
Fast charging of iron phosphate and lithium
titanate oxide cells
Fast charge test data for lithium-ion chemistries
EIG iron phosphate 15 Ah cell
Charge
Current
(Amps)
15
30
45
60
75
90
120
No Taper
60
90
Time to
Taper
Charge to Total
Cutoff
Time
Cutoff
Charge
Discharge
(secs)
(secs)
(Amp-hrs) (Amp-hrs) (Amp-hrs)
3630
210
15.2
15.4
15.50
1770
210
14.7
15.4
15.45
1140
199
14.2
15.4
15.38
840
172
13.9
15.3
15.30
630
184
13.1
15.3
15.29
480
219
11.9
15.2
15.17
240
316
7.9
15.2
15.16
780.4
464.8
12.9
11.6
Temp Rise During Charge
Initial
Temp
Temp
Change
(C)
(C)
22.5
0
22.5
1.5
22.5
3
23.5
4.5
25.5
5.5
23
7
25
9
12.99
11.60
Altairnano titanate oxide 11 Ah cell
Charge
Current
(Amps)
11
22
33
44
55
66
88
Time to
Taper
Cutoff
Time
(secs)
(secs)
3920
81
1950
68.5
1300
57.7
970
59.2
760
74.8
620
83
440
103.1
11.9
11.9
11.9
11.8
11.6
11.3
10.7
Charge
Discharge
(Amp-hrs) (Amp-hrs)
12.0
12.00
12.0
12.00
12.0
12.00
12.0
12.01
12.0
11.97
12.0
11.97
12.0
11.97
Temp Rise During Charge
Initial
Temp
Temp
Change
(C)
(C)
22.5
0
22
0.5
22.5
1.5
23
2.5
21.5
4
22.5
4.5
24
6.5
Five cycle fast charge of the Altairnano 11 Ah cell
Altairnano 11 Ah Fast Charge
5 cycles, 66 A
70
3
60
2.5
40
2
Voltage
30
1.5
20
10
1
Current
0
0
5000
10000
15000
20000
25000
30000
0.5
-10
-20
0
Time (secs)
Voltage (volts)
Current (amps)
50
Repeated fast charging cycles for the 11Ah lithium
Titanate oxide cell
66 Amps
charge to 2.8V
Cycle
1
2
2
3
3
4
4
5
5
12A discharge to 1.5V no active cooling
Time to
Initial
Highest
Charge or Cutoff
charge
Discharge Temp
Temp
Discharge (secs)
Amp-hrs Amp-hrs ( C )
(C)
Chg
614.4
10.24
21.5
26
Dischg
11.19
24
22
Chg
614.7
10.25
21.5
26.5
Dischg
11.18
24
22
Chg
614.5
10.24
21.5
26
Dishcg
11.18
24
22
Chg
614.1
10.24
21.5
26
Dischg
11.17
23.5
22
Chg
614.1
10.24
21.5
26
Conclusions
There are significant trade-offs in energy density,
power density, cycle life, and thermal stability between
the various lithium battery chemistries
In terms of battery performance, there are data
available to evaluate the trade-offs
Knowledge of the battery resistance is key to assessing
the power characteristics. W/kg claimed by the
manufacturer is not a reliable assessment of power
There continues to be uncertainty concerning the
differences in cycle life, power (efficiency), useable
energy fraction, and safety (thermal stability) of the
various chemistries
Fast charging of both titanate oxide and iron
phosphate lithium chemistries appears to be feasible