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Dan Dan DeBiccariDeBiccari & Anthony & Anthony ApplewhiteApplewhite

NASA Aerospace Battery WorkshopNASA Aerospace Battery Workshop

November 17, 2010November 17, 2010

OnOn--Orbit Experience, Life Testing, & Lessons Orbit Experience, Life Testing, & Lessons

Learned with LiLearned with Li--ION batteriesION batteries

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The World’s Leading Provider of Commercial Satellites

� 63 GEO satellites currently on-orbit

� More than 1700 on-orbit years experience

� Workforce of 2,900+

� Greater than 40% share of high power commercial market since 2005

� Provider of hosted payloads for best value government mission solutions

� Broad base of blue-chip customers worldwide

� Over 230 satellites built

� 22 satellites in current backlog

� $1.9 billion backlog as of June 30, 2010

� Facility of 1.2M sq. ft. spanning 30 buildings and 72 acres

� 50+ years heritage of performance and reliability

� 13 awards and 10 launches since January 2009

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Background

� Space Systems/Loral has extensive experience with GEO spacecraft with Li-Ion powered electrical power subsystems (EPS)

� Development, qualification, & life testing initiated in late 1990’s

� SAFT, Varta, Sony/ComDev/AEA, JSB (GS Yuasa)

� First launch in 2005

� Presently 13 spacecraft in-orbit with Li-Ion

� 42 batteries, 990 cells

� Eclipse capability from~7 kW to ~18 kW per S/C

� Current backlog is 22 spacecraft

� 71 batteries, ~1540 cells

� 48–96 cells/spacecraft

� Eclipse capability from~9 kW to ~21 kW

� Adoption of Li-Ion technology was more rapid than SS/L had anticipated

� SS/L has had no active GEO programs using Ni-H2 technology since our first Li-Ion launch in 2005

24 cell SS/L battery with GS Yuasa 102 Ahr cells

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BROADCAST

launched 7/10

launched 7/08

BROADCAST

20kW Platform Satellite20kW Platform Satellite Experience

To date, SS/L has successfully launched 5 20kW-Class satellites

launched 3/10

VIDEO BROADCAST

launched 6/09

MOBILE SERVICES

AUDIO BROADCAST

launched 10/10

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SS/L 10SS/L 10--kW and 15kW and 15--kW Class EPS ArchitectureskW Class EPS Architectures

Li-IonBattery

Li-IonBattery

Solar Array

Bus

DischargeConverters

DischargeConverters

100VLoads

100V

Loads

Power Control Unit(PCU)

BatteryControl Elex

BatteryControl Elex

SequentialShunt Reg

Solar ArraySequential

Shunt Reg

Li-IonBattery

Li-IonBattery

Li-IonBattery

Solar Array

Bus

DischargeConverters

DischargeConverters

DischargeConverters

100VLoads

100VLoads

Power Control Unit(PCU)

BatteryControl Elex

BatteryControl Elex

BatteryControl Elex

SequentialShunt Reg

Solar ArraySequentialShunt Reg

• 10-kW Class Power Subsystem • 15-kW Class Power Subsystem• 3 Batteries• 2 Batteries

Modular EPS Architecture

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SS/L 20SS/L 20--kW and 25kW and 25--kW EPS ArchitectureskW EPS Architectures

Li-IonBattery

Li-IonBattery

Solar Array

Bus

DischargeConverters

DischargeConverters

100VLoads

Power Control Unit(PCU)

Li-IonBattery

Li-IonBattery

Solar Array

Bus

DischargeConverters

DischargeConverters

Power Control Unit(PCU)

100VLoads

100V Bus XStrap

BatteryControl Elex

BatteryControl Elex

BatteryControl Elex

BatteryControl Elex

SequentialShunt Reg

SequentialShunt Reg

• 20-kW or 25kW Class Power Subsystem• 4 Batteries

� 25 kW EPS Capabilities

� Batteries: High capacity Li-Ion batteries

� Solar Array: 8 panels with high efficiency solar cells

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LiLi--ion Battery Capabilitiesion Battery Capabilities

� State of Practice: 102-Ah Li-ion Cell Technology

Battery pack scalable from 18 to 24 cells for flexible power capabilities

GYT 102 Ah Nameplate Li-ion Battery Cell

� 2 Battery System

� Spacecraft power ranges from 8.0 to 11kW

� 3 Battery System

� Spacecraft power ranges from 12 to 18 kW

� 4 Battery System

� Spacecraft power ranges from 20 to 24 kW

� Currently, SS/L is using GS Yuasa 102 Ahr cells for all spacecraft using Li-Ion

� Evolution from ‘heritage’ cell to ‘standard’ cell

Charge Connector – each cell individually charged

Telemetry Connector

Battery Switch Tray

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1300 PRODUCT EVOLUTION TO THE 25kW PLATFORM

� SAFT 180 Whr battery cells provide increased

capability

� Technology for 25 kW is flight proven and available

� Improved energy density results in 20% less mass

� Packaging fits within SS/L’s existing allocated S/C

battery volume

� Works with SS/L’s existing power electronics

� Real time GEO life testing at SS/L initiated in late 2009

on 2P x 24S battery w/ Aeroflex balancing circuitry

� GYT battery 145 Ahr

� 20% improvement in Ahrs/Kg compared

to 102 Ahr cell

� Test cells delivered to SS/L in mid 2010

� Testing will start by end 2010

SAFT 180 SAFT 180 SAFT 180 SAFT 180 WhrWhrWhrWhr cells cells cells cells –––– 2Px24S 2Px24S 2Px24S 2Px24S configconfigconfigconfig....Life Test Battery Assembly in test at SS/LLife Test Battery Assembly in test at SS/LLife Test Battery Assembly in test at SS/LLife Test Battery Assembly in test at SS/L

Qualifying larger capacity Li-ion cells with “next generation” technologies for lower mass and higher power capabilities

GYT 145 Ahr 10 cellGYT 145 Ahr 10 cellGYT 145 Ahr 10 cellGYT 145 Ahr 10 cellLife Test Battery Assembly at SS/LLife Test Battery Assembly at SS/LLife Test Battery Assembly at SS/LLife Test Battery Assembly at SS/L

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Lessons Learned

� High voltage of “discharged” Li-Ion cells & batteries is problematic during battery assembly, test, handling, & integration

� “Hot mates” should be avoided to the greatest extent possible

�Documented & verified procedures, when ‘hot mates’ cannot be avoided

� Spacecraft Thermal Vacuum testing is NOT the place to wring out a new Li-Ion EPS

�Too late in the program to discover a problem

�Schedule pressure limits thoroughness of testing

�Orientation of spacecraft (relative to heat pipe operation) limits testing

�Better to perform……

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EPS “End to End” Test

� Extensive test duration (> 3 months, most in hard vacuum) allows for all “normal” and "off normal" conditions to be actually tested� Use of battery simulator allows variety of failure conditions to be verified

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EPS “End to End” Test was invaluable

� EPS equivalent of an ADCS “3-axis test” performed immediately after unit level qualification testing and well in advance of spacecraft thermal vacuum testing

� Similar to a qual test, done on a non-recurring basis for new EPS design

� Included ALL critical elements of EPS (except Solar Array) as well as flight thermal control, flight software, and flight Data Handling Equipment

� Vacuum sensitive units tested in common thermal vacuum chamber

� Testing augmented with Battery Simulator and Solar Array Simulator

� Major test goals included

� Verify / validate battery thermal control scheme (radiator performance, gradients throughout battery and structure, etc.)

� Stability and bus regulation performance

� Battery management software code validation and compatibility with Li-Ion cells (including database, code, FDIR, etc.)

� Interface and functionality verification of EPS hardware (battery, battery charge electronics, dischargers, etc.)

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Life Testing

�Two best reasons to perform life testing (in order of importance)

� Increases customer confidence when introducing new technology

�Allows life model to be validated

� On-going SS/L life testing:

� Wear Out Testing – 2 cells per flight lot - 3 cycles per day

� 80 Ah real time GEO life test - 10 cells, 12 years in test, 20 seasons

� 92 Ah Real time GEO life test - 10 cells, 3 years in test, 7th season in process

� Full simulation of prelaunch, 2.7 years of storage prior to test at both 10 & 20 deg C (20 deg C simulates battery assembly) at 10% SOC, including 8 weeks of launch base storage at 60% SOC

� SAFT VES180 Real Time GEO life test – 2P x 24S

� 2P x 24S cells, 3 different cell lots in battery, 1 year in test, 2 seasons

� bulk charging with Aeroflex BEU for cell balancing

� GYT 145 Ah Real Time GEO Life test – 10 cells, test scheduled to start 12/10

� Other tests to validate long term storage & new cell materials also in progress

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Performance of ‘Standard’ Electrolyte cells in Wear Out Test

3.300

3.350

3.400

3.450

3.500

3.550

3.600

3.650

3.700

0 100 200 300 400 500 600 700 800

Cell Cycle number

En

d O

f D

isch

arg

e V

olt

ag

e (

V)

Lot 19 AVG

Lot 22 AVG

Lot 24 AVG

Lot 25 AVG

Lot 27 AVG

Test run at 95% DOD of de-rated

capacity (86% of nameplate) – 3

cycles per day

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GEO Real Time Life Test Performance – Heritage Electrolyte Cells

3.56

3.57

3.58

3.59

3.60

3.61

3.62

3.63

3.64

3.65

3.66

3.67

3.68

3.69

3.70

3.71

3.72

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45

Day of Season

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lip

se

Av

era

ge

Dis

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olt

ag

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V)

1st Eclipse2nd Eclipse3rd Eclipse4th Eclipse5th Eclipse6th Eclipse7th Eclipse8th Eclipse9th Eclipse10th Eclipse11th Eclipse12th Eclipse13th Eclipse14th Eclipse15th Eclipse16th Eclipse17th Eclipse18th Eclipse19th Eclipse

Season 1

80 Ah EOCV Adjustments

Seasons 1-5 Seasons 6-9 Seasons 10-16 Season 17-19

3.900V 3.940V 3.950V 3.960V

Season 6

Season 5

Seasons 3 & 4

Seasons 13 & 14

Seasons 15 & 16

Seasons 11 & 12

Seasons 17 & 18

� On-orbit battery management philosophy of periodically adjusting charge voltage to assure proper performance and adequate margins over mission life has been validated

� Real time performance is excellent and correlates well with expectations and Life test model predictions

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GEO Real Time Life Test Performance – Standard Electrolyte Cells

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On Orbit Battery Data - Launch through Present

20102005

8/1

1/0

5

55.1 Ah Max(4.3 Kw per battery12.9 kW total Load)

40.7 Ah Max

Dis

ch

arg

e (

Ah

)T

em

pera

ture

(°C

)V

olt

ag

e (

V)

Stable Performance, very little operator intervention required

Season 1 Season 11Season 3 Season 5

Solstice Voltage set point changed

Solstice temp set point changed

Season 9

2006

Season 7

2007 2008 2009

Ba

t1 C

ap

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t2 C

ap

Ve

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t3 C

ap

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t1 C

ap

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t2 C

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t3 C

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t1 C

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t2 C

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On-orbit capacity verification

�Capacity of one battery is verified prior to each eclipse season.

� It takes 3 seasons to cycle through all three batteries

On-Orbit capacity exceeds model expectations, first Equinox EOCV adjustment predicted after mission life is complete. Actual Vset adjustments are dependent on

future SC loading & cell voltage performance.

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Wrap Up

�Superb Li-ion self-discharge behavior and excellent room temperature performance allow dramatically easier launch base operations vs Ni-H2�No issue achieving desired state of charge for launch

�No need to use umbilical or GSE to charge and maintain batteries

� Flight battery charging hardware/software is already dual fault tolerant and extensively tested and verified

�Capacity verification trending has been great to have

�Essentially a reconditioning style discharge that allows us to collect capacity data over the life of the cells

�Not necessary for battery health, but provides data for SS/L & customers to confirm ‘within predicted’ performance

� Will be a great database as more S/C are launched and multiple seasons are accumulated

�SS/L architecture with individual chargers for each cell was a good choice

�Best way to assure that all cells are charged to the same cutoff voltage

� No other system existed to provide balancing of cells at the time, but…

� A charger failure results in the inability to charge the cell associated with that charger and ultimately the cell will be completely discharged and reversed

� To date we have had a single charger failure (1 of 990)

� This caused the cell to be driven into reverse voltage during subsequent discharge, causing autonomous actuation of the CSD (Cell Shorting Device). This places a 60 micro-ohm current path in parallel with the cell

� Device is fused to provide fault clearing in the event of an unintended actuation of the device

� Cell quantity per spacecraft is based on assumption that a charger failure = a cell failure

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THEN & NOW

Courier – 1960, 500 lbs, 60 watts Mobile Services Sat – 2009, 12,000 lbs, 20,000 watts