Post on 24-Apr-2022
Battery Degradation Testing Update
Daiwon Choi, Nimat Shamim,
Alasdair Crawford, Qian Huang,
Vish Viswanathan, Ed Thomsen
Energy Storage Systems Safety and
Reliability Forum
April 20~21, 2021
2
Li-ion Battery
Lead Acid Battery
Flow Battery
ZEBRA Battery
PROJECT OVERVIEW
Grid Storage Launchpad
In Service Planned
From DOE OE Global Energy Storage Database (source NTESS)
3
Practical Data
Scientific Data
Chemistry
Comparison
Degradation Study
Lifecycle
Prediction
BMS Control
State-of-health
Monitoring
Field Use-Case
Data
Materials Single Cell Modules < 100kW Deployed ESS
PROJECT OVERVIEW
4
❑ Develop testing schedules based on standard protocols for industry specific reliability.
❑ Performance comparison of various commercial Li-ion battery chemistries and formats.
❑ Battery performance data processing and analyses.
❑ Support degradation model, state-of-health and prediction.
❑ Battery degradation mechanism analyses.
❑ Correlate single cell to module with BMS and system performance.
PROJECT OBJECTIVES
55
• Degradation at Rest (Intrinsic)
• Chemistry Material compatibility of components (cathode, anode, electrolyte, etc.)
• Time Chemical reaction is time dependent
• State-of-Charge (SOC) Chemical and structural stability of electrodes depends on Li content
• TemperatureChemical reaction is temperature dependent
• Degradation during Operation (Extrinsic)
• Cell FormatDynamic battery performance depends on cell engineering
• Charge/Discharge Rate (C-rate: unit A/h) Rate effects heat, stress and dendrite formation
• Depth-of-Discharge (DOD or SOC)DOD effects electrode volume change and heat
• HeatHeat produced accelerates chemical reaction
DEGRADATION MECHANISMS
6
0 5 10 15 20 25 30
-2
-1
0
1
3.00
3.25
3.50
3.75
4.00
4.25
25
26
27
28
Cu
rre
nt
(A)
V
olt
ag
e (
V)
Te
mp
. (o
C)
BL
0 5 10 15 20 25 30
-2
-1
0
1
3.00
3.25
3.50
3.75
4.00
4.2525
26
27
28
29
30
0 5 10 15 20 25 30
-2
-1
0
1
3.00
3.25
3.50
3.75
4.00
4.2525
26
27
28
29
30
0 5 10 15 20 25 30
-2
-1
0
1
3.00
3.25
3.50
3.75
4.00
4.2525
26
27
28
29
30
FR DOD
0 5 10 15 20 25 30
-2
-1
0
1
3.00
3.25
3.50
3.75
4.00
4.25
25
26
27
28
29
30
0 5 10 15 20 25 30
-2
-1
0
1
3.00
3.25
3.50
3.75
4.00
4.25
25
26
27
28
29
30
0 5 10 15 20 25 30
-2
-1
0
1
3.00
3.25
3.50
3.75
4.00
4.25
25
26
27
28
29
30
0 5 10 15 20 25 30
-2
-1
0
1
3.00
3.25
3.50
3.75
4.00
4.25
25
26
27
28
29
30
FR SOC
0 5 10 15 20 25 30
-5-4-3-2-101
3.00
3.25
3.50
3.75
4.00
4.25
25
26
27
28
29
Time (h)
EV
0 5 10 15 20 25 30
-2
-1
0
1
3.00
3.25
3.50
3.75
4.00
4.2525
26
27
28
29
Cu
rren
t (A
) V
olt
ag
e (
V)
Te
mp
. (o
C)
Time (h)
PS ❑ Variables
• Time : 24h grid cycle (1day)• State-of-Charge (SOC) : 30, 50, 70%• Depth of Discharge (DOD or SOC) : 20, 40, 60%• Power (C-rate): Max. 0.25, 0.5 & 1 • Temperature : 25oC • Number of cells: 3~4• Schedules
BL : Baseline : aging FR : Frequency Regulation PS : Peak Shaving EV : Electric Vehicle
STANDARD BATTERY TESTING
7
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85
-2.0-1.5-1.0-0.50.00.51.01.5
2.502.753.003.253.503.754.004.25
24
25
26
27
28
29
Cu
rre
nt
(A)
Vo
lta
ge
(V
)
T
em
p.
(oC
)
Time (h)
Current
Voltage
Temperature
0.12 0.13 0.14 0.15 0.16
-0.020
-0.015
-0.010
-0.005
0.000
0.005
0.010
0.015
0.020
0.12 0.13 0.14 0.15 0.16
0%
10%
20%
30% 40%
50%
60% 70% 80%
Z'()
- Z
"()
90%
100%
CV DC resistance OCV
❑ Performance Data Analyses• CV (dQ/dV) : voltage profile change and redox
activity• Capacity: degradation of cell• dV/dQ: cathode or anode capacity change• AC impedance : every 10% SOC• DC resistance : every 10% SOC • OCV : every 10% SOC• Temperature : Cell temperature will be used to
calculate the amount of heat energy released after ARC measurement on each cell
STANDARD BATTERY TESTING
8
0
2
4
6
8
10
12
0 2 4 6 8 10
0
2
4
6
8
10
12
14
0 2 4 6 8 10
0
2
4
6
8
10
12
14
0 2 4 6 8 10
0
2
4
6
8
10
12
0 2 4 6 8 10
0
2
4
6
8
10
12
14
0 2 4 6 8 10
0
2
4
6
8
10
12
14
0 2 4 6 8 10
0
2
4
6
8
10
12
0 2 4 6 8 10
0
2
4
6
8
10
12
14
0 2 4 6 8 10
0
2
4
6
8
10
12
14
0 2 4 6 8 10
0
2
4
6
8
10
12
0 2 4 6 8 10
0
2
4
6
8
10
12
14
0 2 4 6 8 10
0
2
4
6
8
10
12
14
0 2 4 6 8 10
LFP(2.6Ah) NCA(3.2Ah) NMC(3.2Ah) NMC(3.0Ah)
PROJECT RESULTSC
ap
acit
y L
oss (
%)
Time (Months)
Ni 70% Ni 85%
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PROJECT RESULTS
❑ LFP cell show most stable cycling performances.❑ Frequency regulation service most cost effective irrespective of battery
chemistry.❑ Peak shaving degradation is close to EV drive cycle (most deviation).
FR
BL PS
Ni 85% Ni 70%
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PROJECT RESULTS
Months
❑ CV shows cathode structure change with cycles.❑ dV/dQ show which electrode is degrading more. ❑ Accurate CV and dV/dQ of cathode and anode electrode will
be characterized.
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PROJECT RESULTS
OCV Resistance
12
PROJECT RESULTS
13
PROJECT RESULTS
6.E+07
6.E+07
6.E+07
6.E+07
6.E+07
6.E+07
6.E+07
6.E+07
6.E+07
6.E+07
6.E+07
BL
30
BL
50
BL
70
EV
d6
0
FR
40
FR
60
FR
60
LP
FR
80
FR
d4
0
FR
d6
0
PS
d2
0
PS
d4
0
PS
d6
0
Tem
pe
ratu
re
Duty Cycle
Three months average temperature time for each duty cycle in NCA battery
70000000
72000000
74000000
76000000
78000000
80000000
82000000
84000000
86000000
0 20 40 60 80 100 120 140 160 180 200
Area (Temp time)
Average 3month temp 3cells
❑ Cell temperature difference over 25oC (chamber temperature).
❑ Cell temperature variation due to the cell location in the chamber and cooling rate (air flow).
❑ To calculate amount of heat in each cell to understand effect of heat on degradation.
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PROJECT RESULTS
LFP LFP(X) Al(R) NMC(X) NCA NMC1 NMC2
❑ Heat capacity measured using Isothermal Battery Calorimeter.
❑ Total heat will be calculated based on Cp values
❑ Cp of all cells measuredNMC1 (3.0Ah)NMC2 (3.2Ah)Al(R) : Aluminum reference
(X): Cells for Future Additional Test
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❑ Physics and statistics-based state of health model developed.
❑ Continue old test for end-of-life study and characterize degraded cells.
❑ Data analyses on 1 year test results.
❑ Doubling the test capability for additional cell chemistries.
FUTURE WORK
SUMMARY
❑ ~100G of test data accumulated over one year period.
❑ New test setup provides more information with higher accuracy.
❑ In general, higher SOC level and DOD degrades the battery more
but cell chemistry is more important.
❑ LFP cells have better aging, capacity, and energy retention.
❑ Five new chemistries (2 LFP, 2 NMC and 1 LTO) will be added to
the test.
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PNNL is a multi-program national laboratory operated by Battelle for the U.S. Department of Energy (DOE) under Contract DEAC05–76RL01830. This work was supported by the DOE Office of Electricity (OE) under Contract No.57558.
ACKNOWLEDGEMENTS
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Thank You!
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