RAY-O-VAC currently markets a 160 mAH lithium cell recommended for usage in watch and calculator products. The lithium carbon monofluoride cell offers an extended shelf life with no reduction in performance effectiveness. The BR2325 cell has aerospace applications for memory devices and telemetry systems. Over one hundred thirty (130) cells were purchased and tested for evaluation purposes. The test statistics and overall cell performance of the RAY-O-VOC BR2325 lithium carbon monofluoride cell is reviewed

Mcdermott, J. K.

English

NASA Technical Reports Server

RAY-O-VAC BR2325 
LITHIUM CARBON MONOFLUORIDE 
CELL PERFORMANCE 
Joseph K. McDermott 
Martin Marietta Denver Aerospace 
Denver, Colorado 
ABSTRACT 
RAY-O-VAC currently markets a 160 mAH lithium cell recommended for usage 
in watch and calculator products. The lithium carbon monofluoride cell offers 
an extended shelf life with no reduction in performance effectiveness. The 
BR2325 cell has aerospace applications for memory devices and telemetry 
systems. Over one-hundred thirty (130) cells were purchased and tested for 
evaluation purposes. This paper reviews the test statistics and overall cell 
performance of the RAY-O-VAC BR2325 lithium carbon monofluoride cell. 
INTRODUCTION 
The RAY-O-VAC BR2325 lithium monofluoride cell is a commercially available 
product recommended for usage in watch and calculator products. The cell has 
a nameplate capacity of 160 mAH (13,000 Ohms at 21°C to 2.0 V), a volume of 
1.04 cc and a weight of 3.1 grams. The button cell dimensions, depicted in 
Figure 1, comply with the proposed industry standard sizes for lithium cell 
utilized for watch and calculator products (-ref 1). Figures 2 and 3 depict 
advertised discharge characteristics for varying loads and temperatures. 
The RAY-O-VAC BR2325 cell has possible applications for memory backup and 
telemetry systems. The most important features of any battery power system 
are first, reliability, and second, the ability to deliver energy with a good 
volumetric efficiency. Most lithium cells, including the BR2325, fulfill the 
second requirement but have not clearly demonstrated the first. Therefore, a 
goal of the test program was to establish a reliability data base for 
consideration of the monofluoride cell for future aerospace usage. Another 
important feature of a lithium power system, due to the historical backgound 
of lithium couples, is the safety considerations associated with the lithium 
battery. The fact that not all lithium cellslbatteries are hazardous is 
demonstrated by the existence of certain lithium batteries, such as the 
BR2325, in the commercial market (ref 2). 
https://ntrs.nasa.gov/search.jsp?R=19850023069 2020-03-20T17:23:50+00:00Z
The procurement of 130 BR2325 cells specified the cells be manufactured 
from the same lot and on the same day. The cells were manufactured 08 April 
1983 at the RAY-0-VAC Corporation in Madison, Wisconsin. The testing 
facilities, test plan and test statistics are reviewed in the following 
paragraphs. 
TEST FACILITIES 
The evaluation testing of the RAY-0-VAC BR2325 cells was conducted at the 
Experimental Battery Test Facility (EBTF), a dedicated facility for performing 
testing and evaluation on experimental battery types such as high energy 
density lithium batteries. The facility is equipped with seven temperature 
test chambers and a dedicated data acquisition system. Each of the test 
chambers is capable of maintaining temperatures of minus 40°F to plus 
350%'. The chamber-s have been modified to accommodate six modular test 
fixtures designed for cells such as the BR2325. The chamber test patch panel, 
mounted externally, is the interface point for the Data Acquisition System and 
the mounting location for the test load resistors. 
The EBTF Data Acquisition System consists of a 420 channel Fluke Model 
2240C Data Logger, a Commodore PET computer and a Texas Instrument Silent 700 
Electronic Data Terminal. This system, depicted in Figure 4, is controlled by 
the test monitoring software resident in the 32K PET computer. All test data, 
including cell voltages and chamber temperatures, is monitored approximately 
every two minutes. When a data recording is required, as determined by cell 
voltage rate of change or prescribed data record interval, the data record is 
transmitted to the electronic data terminal where it is recorded on cassette 
magnetic tape and printed on hardcopy. 
TEST PLAN 
The test plan for the RAY-0-VAC BR2325 cells is summarized in Table 1. 
The cells were tested at six discharge rates and five temperatures. Twelve 
cells were placed in ambient storage for 6 months and six cells for 12 months 
to measure the effect of long term storage on the BR2325 cell. 
TEST SUMMARY 
The average capacities for the BR2325 cell as a function of temperature 
and discharge rate are summarized in Tables 2 and 3. Typical discharge curves 
for the five test temperatures at the 30 day discharge rates are provided in 
Figures 5 through 9. Figure 5 illustrates the voltage sensitivity of the 
BR2325 cell to test temperature changes for the low temperature (-10°~) 
test. The voltage sensitivity versus test temperature changes was not as 
pronounced for the other test plan temperatures. As expected, the RAY-0-VAC 
BR2325 cell generally provided the greatest capacity at the +7S°F test 
temperature. The capacities obtained at the various discharge rates and 
temperatures generally agreed with the RAY-0-VAC literature on the lithium 
carbon monofluoride cell. 
The effect of long term storage on the cell performance of the BR2325 cell 
is negligible. Figure 10 depicts the discharge profile for the median cell 
from the 12 month storage test group. The cell performance was nearly 
identical to the performance of a cell not subjected to long term storage, 
CONCLUSIONS 
The overall cell performance of the RAY-0-VAC BR2325 lithium carbon 
monofluoride cell was acceptable from a statistical viewpoint. The 
coefficient of variation was generally below 5% and the standard deviation was 
generally less than 10 milliampere-hour for the five cell test groups. The 
statistical uniformity is attributed partly to the fact the cells came from 
the same manufacturing lot. 
The low capacities at -10°~ can be attributed to the rate reductions of 
the energy producing chemical reactions within the lithium carbon monofluoride 
cell. The voltage stability at the low temperature was excellent provided the 
test temperature of -10O~ was stable. The voltage sensitivity to test 
temperature changes for the high temperature tests was minimal. The reduced 
capacities at the high temperature are attributed to the speed up in battery 
deterioration. 
The BR2325 cell appears to be a viable candidate for aerospace 
applications for memory devices and telemetry systems. The cells tested were 
"off the shelf" hardware which uniformally~supported the resistive loads. A 
special build of the RAY-0-VAC BR2325 cell for a particular aerospace 
application should provide a reliable energy storage system. 
REFERENCES 
1. Crompton, T. R., Small Batteries Primary Cells Volume 2, John Willey and 
Sons, Inc., New York, 1983. 
2. Smith, J. J., "Research Issues in Future Navy Lithium Inorganic 
Electrolyte Batteries for Navy Application", Naval Undersea Center TP 564, 
February 1977. 
Table 1 .  RAY-0-VAC BR2325 LITHIUM CARBON MONOFLUORIDE TEST PLAN 
Resistive 
Load (Ohms) 
Discharge 
Current (mA) 
Test . 
Temperature Discharge Rate 
53 Hrs 
53 Hrs 
53 Hrs 
80 Hrs 
80 Hrs 
80 Hrs 
160 Hrs 
160 Hrs 
160 Hrs 
30 Days 
30 Days 
30 Days 
30 Days 
30 Days 
90 Days 
90 Days 
. 90 Days 
90 Days 
90 Days 
180 Days 
180 Days 
180 Days 
180 Days 
180 Days 
Storage 8 months 
Storage 10 months 
Storage 12 months 
Table 2. AVERAGE CAPACITY TO A 2.0 VOLTAGE CUTOFF 
Discharge Rate Test Temperature O F  
-10 32 
-
7 5 
-
120 
-
160 
-
53 Hns (3.0 mA) 081 110 170 
80 Hrs (2.0 mA) 087 122 165 
160 Hrs (1.0 mA) 098 14 2 155 
30 Days (0.22 mA) 043 146 173 168 141 
90 Day8 (0.074 mA) 086 15 5 13 7 146 102 
180 Days (0.037 mA) 093 169 171 130 104 
Table 3. AVERAGE CAPACITY TO A 0.2 VOLTAGE CUTOFF 
Disgharge Rate 
30 Days (0.22 mA) 
90 Days (0.074 mA) 
180 Days (0.037 mA) 
Test Temperatur.6 O F  
- 10 32 
-
75 
-
120 
-
160 
-
149 149 172 
BUTTON CELL DIMENSIONS: 
--.-- 
~ n e n m  in mm r ' ~ - j  I 
2 
f > 2.20/2.50 
+ 
mn 2.20 2.50 48.m Z.50 23.00 
n. 087 OPd 709 886 9% 
Figure 1. Ray-0-Vac BR2325 Cell Dimeilsions 
W 
(1 
* 3.0 S 
0 
* 2.5 
:: 
= 2.0 Y 
H 
u 6 1.5 
rn 8 1.0 
0 2000 4000 6000 
SERVICE LIFE (HOURS) 
Figure 2. Ray-0-Vac BR2325 Service Life Versus Load 
SERVICE LIFE (HOURS) 
Figure 3 .  Ray-0-Vac BR2325 Service Life Versus Temperature 
HARDCOPY OUTPUT 
(Test Data. System Statue, Etc.) 
1 
Tape DrivelTape Drive FLUKE 
Printer 1 1  2 22406 
---------  -,,- 1,,,, DATA 
TI SILENT LOGGeR C(NMOD0RE . . 
700 ELECTRONIC PET 2001 
DATA TERMINAL COMPUTER - - - - - - - -  
- - - - - - - - - -  - - - - - - - - a  Extender 
Cassette Keyboard/CRT 1 
Tape Drive - - - - - -  
Extender 
2 
--- - - - - 
Extender 
3 
i )  -- MAGNFXIC TAPE OUTPUT 
(Test Data) OPERATOR 
INPUT/OUTPUT 
Figure 4. EBTF Data Acquisition System 
Cell Voltages /'- 
Test Temperatures G 
Figure 5. Median Cell Voltage Versus Time and Temperature, -1 O°F 
TINE (HOURS1 
t .TEMPERATURE FLUCTUATIONS 
FRON 1 2 0  TO 1 0 0 0  HOURS RRE 
DUE TO CHAMBER CYCLING. 
~ i ~ u i e  6. Median Cell Voltage Versus Time and Temperature, 32OF 
TINE (HOURS) 
Figure 7. Median Cell Voltage Versus Time and Temperature, 7S°F 
TIME (HOURS) * POWER FAILURE ++ POWER FAILURE8 TEMP. DROP TO 1 0 0 F .  
Figure 8. Median Cell Voltage Versus Time and Temperature, 120°F 
TIRE (HOURS) * POWER FAILURE RESULTED 
I N  CHAMBER FAILURE, TEMP 
DROP TO 100 DEGREES. 
135 
130 
-- 
_ ......................................................................... 
Figure 9. Median Cell Voltage Versus Time and Temperature, 160°F 
, VOLTAGE CUTOFF: 0 .2  VOLTS : 
TEST LENCTHI 30 DAYS 
CELL SERIAL NUUBER: 0 7 6  
LOAD: 12.08 KOHMS 125- 
t " ,  
. W 
............................................. 
5 
120& 
. IY 
W 
, P 
E 
. W 
............................................ - l i s +  
- ..................................................... .......................................... ....................................................... 110 
I'lEDIRN CELL VOLTRGE VERSUS : 
TINE AND TEMPERATURE 
TEST NUMBER1 8307-28-116 ' 
CELL HAnE: RAY-0-VAC ~ ~ 2 3 2 s '  
"'CHEMISTRY r L I 4 F  
Figure 10. ~ e d L h  Cell Voltage Versus Time and Temperature, 6 Month Storage, 
Test Number: 8404-03-010 Cell Nena: RAY-O-VAC BR2325 
Test Length: 6 ao. Storage. 90 Day D/C Chemistry: LilCP 
Test Temperature: 7S0P Voltage Cutoff: 0.2 Volts 
Load: 36.5 K-Ohms Cell S/N: 053 
150 
125 
4 
m 
M 
100: 
n 
x 
D 
m 
75 ; 
C 
w 
m 
- 
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0) 
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- 
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0 
3000 
3.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  
I CELL S/N 053 VOLTRGE 
TINE (HOURS) 
2 - 5  
- 
1'1 
I- 
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............................................................................ ................................ - L........................ ;. ....- 
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0 500 1000 1508 2800 2500 
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RAY-O-VAC BR2325 Lithium Carbon Monofluoride Cell Performance

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