Batteries were used on the Long Duration Exposure Facility (LDEF) to provide power to both the active experiments and the experiment support equipment such as the Experiment Initiative System, Experiment Power and Data System (data acquisition system), and the Environment Exposure Control Canisters. Three different types of batteries were used: lithium sulfur dioxide (LiSO2), lithium carbon monofluoride (LiCF), and nickel cadmium (NiCd). A total of 92 LiSO2, 10 LiCF, and 1 NiCd batteries were flown on the LDEF. In addition, approximately 20 LiSO2 batteries were kept in cold storage at NASA LaRC. The various investigations and post-flight analyses of the flight and control batteries are reviewed. The primary objectives of these studies was to identify degradation modes (if any) of the batteries and to provide information useful to future spacecraft missions. Systems SIG involvement in the post-flight evaluation of LDEF batteries was two-fold: (1) to fund SAFT (original manufacturer of the LiSO2 batteries) to perform characterization of 13 LiSO2 batteries (10 flight and 3 control batteries); and (2) to integrate investigator results

Dursch, Harry

Johnson, Chris

Spear, Steve

English

NASA Technical Reports Server

N93-1058
Results from the Testing and Analysis of LDEF
Batteries
9
Steve Spear
Harry Dursch
Chris Johnson
Boeing Aerospace
Results from Testina and Analysis of LDEF Batteries
Batteries were used on LDEF to provide power to both the active experiments and the experiment support
equipment such as the Experiment Initiate System, Experiment Power and Data System (data acquisition system),
and the Environment Exposure Control Canisters.
Three different types of batteries were used: lithium sulfur dioxide (LiSO2), lithium carbon monofluoride (LiCF),
and nickel cadmium (NiCd). A total of 92 LiSO 2, 10 LiCF, and 1 NiCd batteries were flown on LDEF. In addition,
approximately 20 LiSO 2 batteries were kept in cold storage at NASA LaRC. This presentation reviews the various
investigations and post-flight analyses of the flight and control batteries.
The priman/objective of these studies was to identify degradation modes (if any) of the batteries and to provide
information useful to future spacecraft missions. Systems SlG involvement in the post-flight evaluation of LDEF
batteries has been two-fold: (1) funding SAFT (original manufacturer of the LiSO 2 batteries) to perform
characterization of 13 LiSO 2 batteries (10 flight and 3 control batteries) and (2) integrate investigator results. No
testing of LDEF batteries occurred at Boeing.
619
https://ntrs.nasa.gov/search.jsp?R=19930001401 2020-03-17T09:47:27+00:00Z
A total of 92 LiSO 2 battery packages (provided by NASA LaRC) were flown on LDEF. These batteries were
divided into three voltages: 7.5, 12, and 28 volts. The individual cells were D-size and manufactured by Duracell
(the Duracell LiSO 2 division has been purchased by SAFT America). Because many of the active experiments
and LDEF support systems experienced cutoff prior to expending the total battery capacity, a large number of
batteries had substantial remainit=g charge when LDEF was retrieved. Several control batteries were kept in cold
storage at NASA LaRC throughout LDEF's mission and were then made available to the battery community.
During LDEF de-integration at Kennedy Space Center, all batteries were checked for evidence of leaks and post-
flight voltages determined. No remaining capacity measurements were made.
SAFT America received 10 flight batteries and 3 control batteries for comparative evaluation and destructive
physical analysis. The results are contained in the footnoted reference. The retained capacity testing of three
control batteries showed that the capacity loss over approximately 69 months was around 11%. The one unused
battery flown on LDEF suffered an almost 30% capacity loss. The difference in capacity loss is attributed to
differences in ambient temperatures. The ground-stored batteries did not see temperatures above 40°F whereas
the flight batteries were subjected to temperature ranges from 40 ° F to over 95 ° F during the LDEF mission. The
LiSO 2 batteries suffered capacity loss due to parasitic reactions.
The following four figures show representative photographs of the LiSO 2 battery disassemblies performed at
SAFT. This figure shows both a LiSO 2 battery case disassembled and a close up of a LiSO 2 cell block.
* Raman, "Experimentation and Destructive Physical Analysis for the Space-Exposed LiSO 2 Batteries from the
LDEF," SAFF America, Inc., 1991.
620
US02 Battery Case Disassembled
Closeup of LiS02 Cell Block
BLACK AND WHILE PH{:lt OGRAPH
621
Results of LISO 2 Investlaations Con_t
This figure shows a USO 2 cell opened and a close up of the corrosion around the glass to metal seal. The
corrosion around the seal was expected and was also found on the control batteries.
LIS02 CellOpened
Terminal ( + )
Cell case
s insulator
622
Closeup of Glass to Metal Seal
8LACK
.... _"s_ z'.,
AND WHITE PHGT['K;RAPH
Results of LISOo Investiaations Con't
=K
Shown is the condition of the lithium anode and the carbon cathode from a control battery.
condition of the lithium strip.
Note the good
US02 Ceil Electrode Materials
LJ_ium
Carbon
cathode
LiSO 2 Cell Components- Control Cell
t ,,.,,_i_, - _-......,.
BLAC,_, A_D V,_,{_E Pt-',OTOGRADH
623
Results of LISOo Investioations Con't
dm
This photo shows the lithium and carbon from a flight battery that was at a 35% state of charge.
of lithium.
Note the absence
Carbon
LiSO 2 Cell Components - Flight Battery With a 35% State of Charge
624
_,,,,:,_IN_L P,-_ ,-_
6LACK AND WHITE PHOTOGRAPH
Inv_stioatlon of LiCF Batteries
Investigation of the LiCF batteries has been performed by AZ Technology, NASA MSFC, and Naval Weapons
Support Center. All ten LiCF batteries were used on the two active MSFC experiments: four batteries were used
on the MSFC heat pipe experiment (Experiment $1005) and the other six were used on the Thermal Control
Surface Experiment (Experiment S0069). As predicted, all ten batteries were depleted on return of LDEF. The
required experiment life was 12 months, with an expected life of 15 to 18 months. All ten batteries met or
exceeded life expectations
The cells were roughly double D size having vented construction with a rated capacity of 25 Ah and a nominal
voltage of 3 volts. The cells were potted in a plastic block and hermetically sealed with a "can opener" vent for
relief of cell over-pressure.
LiCF BATTERIES
• Used on MSFC experiments
• S0069 & S1005
• All ten batteries returned depleted
• S0069 battery life was 19.5 months
• Anticipated lifetime was 15-18 months
• Noticeable order evident for all batteries
• Source identified as the electrolyte
• O-ring did not operate as designed
625
LICF Electrolyte Leakaae
All ten LiCF batteries possessed a strong odor, first noticed during the deintegration of S0069 and S1005 at
MSFC. The electrolyte used in the Eagle-Picher Industries LiCF batteries is dimethyl sulfite, which contains small
amounts of other sulfur compounds that can be quite odorous. AZ Technology investigated the cause and effect
of the leaked electrolyte vapors from the ethylene propylene battery containment case. The presence of the odor
was determined to be the normal byproduct of the discharge process. The LiCF cell is designed with an expansion
diaphragm on the top of the cell with a sharp, rigid protrusion adjacent to the diaphragm. This photo shows a LiCF
battery (made up of 13 individual cells) removed from the battery case. The diaphragm expanded during the slow
discharge process when internal cell pressure increased. Eventually the diaphragm was punctured, releasing the
electrolyte vapors. The cells were sealed in battery boxes. The O-ring seal experienced softening and
deformation due to the extended exposure to the electrolyte vapors which allowed the vapors to leak from the
battery box. However, this created no performance problem for the battery or associated experiment hardware. It
is important to note that the ground-stored LiCF batteries experienced the same phenomena.
626
LiCF Cells Removed From Battery Case
Expansion
diaphragm
LiCF Cell
8LACK Ar',_O V_';-I,_I-E Pi_OiOGR,_PH
627
LICF Voltaoe Versus Time On-orbit
This figure, provided by AZ Technology, showsthe gradual degradation of battery voltage versus time for one of
the four batteries used on S0069.
Lithium Carbon Monofluoride Batteries - LDEF Flight Data
Gradual Degradation of Voltage with Fli_ht Duration
4O
Voltage
12 Month Mission - Achieved
12 to 18 Month Expected Life - Achieved
35
30
25
20
150
i I i i I t ,
200 250 300 350 400 450 500 550
Mission Time (Days)
Max Daily Voltage _ Min Daily Voltage
628
Investlaation of the Nickel Cadmium Battew
One NiCd battery manufactured by General Electric was flown on the LowTemperature Heat Pipe Experiment
(Experiment $1001 ). This battery was continuouslycharged by a four arrays of solar cells which were located on
the space end of LDEF. Analysis and testing of the battery was performed by S. Tiller and D. Sullivan of NASA
GSFC. The batteryconsisted of 18 cells, which were mountedon an aluminum baseplate. Pre-flight power
analysis for the 12 Ah NiCd battery indicated a need for 2 to 3 amp discharge. However, reduction inthe
experiment current requirements duringflight resultedin much lower power demand. This led to an overcharging
situationthat caused the development of internal pressure, resultingin the bulging of the cell case. This bulging is
especially noticeable on one end of the cell pack, as shown in this figure.
LDEF/HEPP
POWE R SY ST E M BAT T E R Y
..........................................t ' C!:! ! ...............................................................iL
Bulged portion of battery case
Bulging of NiCd Battery Case
_:,, :;i;_:.L, ':, '".."
BLACK /'_:,D WrJ,il E ;.'_.,C_1)GRAPH
629
Loss of NICd Overcharae Protection
The loss of overcharge protection is obvious from the difference in voltage performance shown for the pre-flight
and post-flight measurements of cells on constant current, as shown in this figure. Pre-flight charge profile
showed all cells were matched and reached full state of charge in 18 hours, while maintaining voltage below 1.46
volts. Post-flight data showed considerable differences between cells with cell #10 (this cell bulged the most
during the mission) reaching a hi_lh voltage of 1.52 volts which tripped the charge for the battery off at 14 hours of
charge. Discharge testing produced similar results.
Despite the obvious bulging of some cells, loss of overcharge protection, and failure of cell #10 during the open
circuit recovery test, the battery still had the capability to provide output current in excess of the cell manufacturer's
rated capacity of 12 Ah.
NiCd Battery
Constant Current Charge Indicates Loss of Overcharge Protection
CHARGE. CONS TANT CURRENT (C/I O). Ambienl
SECIUENCEIS4 DATE t2Jo2/I¢3 'RMESTARTED: 13::)Oo0 1 STUNIT:
1.5
_1.45 ..............
$
:12 -,3
1 ' , .....
• 0 2 4 8 8 10 12 14 16
Elapsed Time (hours)
TES UNIT: POWER SYSTEM
18 20
Prc-f|ight Capacity Charge
SEQUENCE m 8d
15.
_D45
_ 14-i
CHARGE- CONSTANT CUt-IRENT (C/tO). A_nb_otd
DATE 06/04RO 13ME STARTED: 20 00 DO TJEST UNIT: POWER SYSTEM
=_..I
If
1 35
0 2 4 6 8 10 12 14 _* 16 10 20
Elapsod "i3me (horns)
Post-lligh! Capacity Charge showing loss or"overcharge protection
630
Summary of LDEF Batten/Findinas
All LDEF batteries were mounted on interior surfaces of LDEF and, therefore, experienced a mild temperature
environment. All batteries met or exceeded their predicted post-flight state-of-charge.
The LiSO 2 batteries exhibited good charge retention, with a loss in capacity of an unused flight battery of less
than 5% per year. The LDEF LiSO 2 batteries showed charge retention properties commensurate with that
expected, based on the temperatures experienced by these batteries. The favorable performance underscores
the merit of the selection of LiSO 2 batteries of similar design for the Galileo mission.
Testing completed at the Naval Weapons Support Center investigated the post-flight condition of three LiCF
batteries: one flight battery provided by MSFC, one control battery discharged to 0 volts prior to dissection, and
one control battery dissected as received. Their findings showed that no significant changes occurred in the
chemistry or function of the LiCF cells as a result of operation on LDEF. The differences found in material
compositions were either trivial, or when significant, a result of long term degradation of cell electrolyte in storage
prior to discharge.
The NiCd battery showed the effect of loss of overcharge protection. However, this did not affect the on-orbit
performance.
For additional information, the reader is referred to the Systems SIG report dated February, 1992.
LDEF BATTERY SUMMARY
• LDEF batteries met and exceeded design requirements
and predicted lifetimes.
• LiCF flight batteries experienced leakage of
electrolyte vapors.
• Similar phenomena occurred for ground stored LiCF
batteries.
• NiCd battery suffered loss of overcharge protection.
631



Results from the testing and analysis of LDEF batteries

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