Upload
others
View
18
Download
0
Embed Size (px)
Citation preview
AMPED SENSOR: Smart Embedded Network of
Sensors with Optical Readout
AMPED Meeting 2015, Chicago, IL
Project Team
Ajay Raghavan (PI), Peter Kiesel,
Anurag Ganguli, Julian Schwartz,
Andreas Schuh, Alex Hegyi, Bhaskar Saha
Mohamed Alamgir, Jeffrey West,
Paul Laurain, Robert Busser, Adnan Haider,
HoeJin Hah, ChaeAh Kim
www.parc.com/sensor
/Key Personnel
SENSOR Overview
2
• Fiber-optic (FO) cell sensing, smart algorithms for BMS
• Low-cost, high-accuracy, field-able PARC readout
• LG Chem Power expertise for EV-grade technology
Cell State Sensing
with FO Sensors
3 www.parc.com/sensor
FO Sensor Example: Fiber Bragg Gratings
(FBGs)
• Can be selectively sensitive to various stimuli: Strain, temperature, chemical conc., current, voltage
• Multiplex-able for multiple sensors on single FO
• Hair-thin, light-weight, EMI-free, robust
wavelength
reflectio
n
white
light
wavelength
reflectio
n
wavelength
reflectio
n
white
light
gain medium
fluidic
channel
mirror
n2
n1
wavelength
outp
ut
inte
nsity
wavelength
outp
ut
inte
nsity
white
light
λ1
wavelength
reflectio
n λ1 λ1+Δλ
stimulus
white
light
λ1
wavelength
reflectio
n λ1 λ1+Δλ
wavelength
reflectio
n λ1 λ1+Δλ
stimulus
λ1white
light
wavelength
reflectio
n λ1 λ1+Δλ
stimulus
λ1white
light
wavelength
reflectio
n λ1 λ1+Δλ
wavelength
reflectio
n λ1 λ1+Δλ
stimulus
Photonic crystal sensor
Silicon micro-sphere sensor
Surface plasmon resonance sensor
Laser cavity sensor
Fiber Bragg grating sensor
wavelength
tra
nsm
issio
n
white
lightwavelength
tra
nsm
issio
n
wavelength
tra
nsm
issio
n
white
light
4
Early Study for External Strain, Temperature
λ2 (loose)
Readout
λ1 (fixed)
“Loose” external FBG picks temperature only
Cell-fin-cell setup mimics module pressure, cooling
5
Mechanical Strain Across C Rates
Curves very similar across C rates, incl. dynamic cycles
Accurate SOC algorithms trained on few static cycles 6
FB
G s
ignal (p
m)
FB
G s
ignal (p
m)
FB
G s
ignal (p
m)
Intercalation Stages from FBG Strain Signal
• FBG derivative peaks match across C rates
• Useful for SOX estimation; stage shifts indicate aging
• Peaks of cell V signal derivative weaker, vary w/ C-rate
FB
G s
ign
al d
eriva
tive
(p
m/s
)
7
From Sethuraman 2010
Graphite Stage 4 Stage 3 Stage 2 Stage 1
FBG derivative peaks Ξ
intercalation stage transitions
SOC (%)
External FBG: Preliminary Comparison w/
Electrical Strain Gage, NTC Signals
8
FB
G s
ign
al (p
m)
FO
sig
nal (p
m)
Str
ain
gage s
ignal (με)
Time (hours)
FO
sig
nal (p
m)
NT
C s
ignal (o
C)
Time (hours)
No load CC Charge CV No load
“Loose” FBG v/s NTC thermistor FBG strain v/s electrical strain gage
Electrical strain gage signals seem not as repeatable
NTC signal shows tendency to pick up EMI
Pouch Cells w/ Internally Embedded FO
Stable embedded config w/ FBGs bonded to electrode
Approach extended to large-format cells 9
15 Ah large-format
1.5 Ah small-format
Internal Small-Format Cell FBG Signals Internal FBG signal FBG T signal
Internal signals 2-5x stronger than external, repeatable
Cell internal temp., other useful SOX features detectable
FB
G s
ignal (p
m)
Time (h)
10
Internal FBG Robustness: Dynamic Cycles
11
Internal more robust than external; both better than cell V
2.5% SOC or better achieved in dynamic cycles
SOH with Internal FBG Signals: Early Results
• Experimental chemistry: cell life ~100 cycles
• Steady increase in base FBG wavelength over life
10-cycle look-ahead capacity prediction error of <1.8%!
Also possible to detect subtle overcharge, failures 12
Time (hrs)0 50 100 150 200 250 300 350 400 450 500
Com
pensate
d s
train
(in
pm
)
-60
-40
-20
0
20
40
60
80
100
120
Cycle number0 10 20 30 40 50 60 70
Cell c
ap
acity d
uring d
ish
carg
e (
Ah
)
0.97
0.98
0.99
1
1.01
1.02
1.03
1.04
Cycle number
Dis
ch
arg
e c
apacity (
Ah)
Mechan
ical str
ain
(pm
)
Time (hours) Discharge cell capacity (Ah)0.97 0.98 0.99 1 1.01 1.02 1.03 1.04
Str
ain
at e
nd o
f cha
rge (
pm
)
20
30
40
50
60
70
80
90
100
110
Discharge cell capacity (Ah)0.97 0.98 0.99 1 1.01 1.02 1.03 1.04
Volta
ge (
V)
4.336
4.338
4.34
4.342
4.344
4.346
4.348
4.35
Discharge cell capacity (Ah) Discharge cell capacity (Ah) V
oltage (
V)
FB
G s
train
at end o
f charg
e (
pm
)
FBG base λ (pm) Rest cell V:
Change within BMS
voltage accuracy
Results towards xEV Pack
Field Deployment
13 www.parc.com/sensor
14
Functional Cells w/ Embedded FO
Cell performance unaffected by FO sensors (30+ cells)
FO sensors with certain coatings unaffected in electrolyte
Experimental cell capacity
w/ cycling
Signal drift in long-term
stability test
-60
-40
-20
0
20
40
60
0 10 20 30 40 50
Wavelen
gthshi(pm)
Time(weeks)
FBGsignal +3degC -3degC
PARC’s Low-Cost Multiplexed FO Readout
• 10 fm accuracy (~0.01 με), up to 1000 channels
• 3-7% pack cost feasible for SENSOR system
• xEV vibration robustness demo’ed (200 fm or better)
SENSOR can replace BMS electrical sensing
15
Prototype size:
8” x 4.5” x 4”
Prod. size:
3.5” x 3” x 0.7” C/2 charge cell FBG
signal w/ new readout
External FO 2011 Volt
1 of || strings monitored
Savings: $856+ 8.3 lbs.
Cost: $294+ 0.2 lbs.
Net: $562 + 8.1 lbs.
Internal FO 2011 Volt
All cells w/ embedded FO
Savings: $1134+ 19.2 lbs.
Cost: $333 + 0.2 lbs.
Net: $801 + 18.9 lbs.
Costs comparable; internal can offer more oversizing trim
Low added $ for more sensors; more value w/ big packs
Fewercells$100
Vharness$90
isensor$28
HighVsensor$10
Tsensor$19
Isola on$204
BMSboards$354
Electronicsrecycling
$7
Lightweight$29
Coolantsensor$15
Ext. v/s Int. FO Sensing Value: 2011 Volt
Fewercells$328
Vharness$90
isensor$28
HighVsensor$10
Tsensor$19
Isola on$204
BMSboards$354
Electronicsrecycling
$7
Lightweight$67
Coolantsensor$28
16
Ongoing Validation, Module-Level Tests
• Presently 4-cell module; larger module test w/ OEM
• Modest training, more testing: xEV dynamic, T-tests
• For internal FBGs: similar SOC tests, plus stress tests
• Also instrumenting in PARC e-Bike fleet Li-ion packs
17
Dynamic discharge
AMPED Attendees’ Pooled BMS Challenges
18
SENSOR project addresses 40% of attendee-BMS issues
Summary and Concluding Remarks Exciting results for BMS sensing, cell state challenges:
• FO new BMS sensing mode for cell state, aging
• Promising cell-level results: 2.5% accurate SOX
• Shown path to field deployment with PARC readout
• Cost-perf. model indicates pack trim w/ simpler BMS
In OEM discussions for further validation, tech transfer
19
Fewercells$328
Vharness$90
isensor$28
HighVsensor$10
Tsensor$19
Isola on$204
BMSboards$354
Electronicsrecycling
$7
Lightweight$67
Coolantsensor$28
wavelength
reflection
white
light
wavelength
reflection
wavelength
reflection
white
light
gain medium
fluidic
channel
mirror
n2
n1
wavelength
outp
ut
inte
nsity
wavelength
outp
ut
inte
nsity
white
light
λ1
wavelength
reflection λ1 λ1+Δλ
stimulus
white
light
λ1
wavelength
reflection λ1 λ1+Δλ
wavelength
reflection λ1 λ1+Δλ
stimulus
λ1white
light
wavelength
reflection λ1 λ1+Δλ
stimulus
λ1white
light
wavelength
reflection λ1 λ1+Δλ
wavelength
reflection λ1 λ1+Δλ
stimulus
Photonic crystal sensor
Silicon micro-sphere sensor
Surface plasmon resonance sensor
Laser cavity sensor
Fiber Bragg grating sensor
wavelength
transm
issio
n
white
lightwavelength
transm
issio
n
wavelength
transm
issio
n
white
lightContact: [email protected]