Evaluation of Saft Ultra High Power 

Lithium Ion Cells (VL5U) 

by Jan L. Allen, Jeff Wolfenstine, Kang Xu, 

Donald Porschet, Thomas Salem, Wesley Tipton, 

 Wishvender Behl, Jeff Read, T. Richard Jow, and Sonya Gargies 

ARL-TR-4731 February 2009 

Approved for public release; distribution unlimited. 
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Army Research Laboratory 

Adelphi, MD 20783-1197 

ARL-TR-4731 February 2009 

Evaluation of Saft Ultra High Power 

Lithium Ion Cells (VL5U) 

 

Jan L. Allen, Jeff Wolfenstine, Kang Xu, Donald Porschet, Thomas Salem, 

Wesley Tipton, Wishvender Behl, Jeff Read, T. Richard Jow 

Sensors and Electron Devices Directorate, ARL 

and 

Sonya Gargies 

U.S. Army Tank-Automotive Research, Development and Engineering Center 

Approved for public release; distribution unlimited. 
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Evaluation of Saft Ultra High Power Lithium Ion Cells (VL5U) 

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6. AUTHOR(S) 

Jan L. Allen, Jeff Wolfenstine, Kang Xu, Donald Porschet, Thomas Salem, 

Wesley Tipton, Wishvender Behl, Jeff Read, T. Richard Jow, and Sonya Gargies 

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U.S. Army Research Laboratory 

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13. SUPPLEMENTARY NOTES 

14. ABSTRACT 

We evaluated Saft Ultra High Power (UHP) cells (Saft designation VL5U) to determine their rate capability, low temperature 

performance, storage, and cycle life. The energy and power density at 5 A (1C) were 45 Wh/kg and 55 W/kg, respectively; at 

1000 A (200C) were 25 Wh/kg and 10 kW/kg, respectively; and at a 500 A rate, the energy densities were 35, 29, and 29 

Wh/kg at 20, –20, and –40 °C, respectively, and the power densities were 4.3, 3.9, and 3.6 kW/kg, respectively. The VL5U 

showed a high rate of self-discharge (tested at 70 °C). Our cycling testing showed that high rate cycling degrades the cell 

faster than high temperature cycling, revealing significant self-heating at high rates of discharge. These results indicate the 

cell design is immature; further development will remediate the high self-discharge rates and the self-heating during high rate

discharge. Pulse discharge testing using a capacitive load showed that, at an output voltage of 2 V, a pulsed current of 8750 A 

may be achieved. The minimum cell resistance from the pulse testing was measured to be about 0.23 mΩ. 

15. SUBJECT TERMS

Lithium ion batteries, high power, low temperature 

16. SECURITY CLASSIFICATION OF:

19a. NAME OF RESPONSIBLE PERSON

Jan Allen 

a. REPORT 

U 

b. ABSTRACT 

U 

c. THIS PAGE 

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OF PAGES 

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301-394-0291 

Standard Form 298 (Rev. 8/98) 

Prescribed by ANSI Std. Z39.18
iii 

Contents 

List of Figures iv

List of Tables v

1. Introduction 1

2. Approach 1

3. Results 2

3.1 Discharge Behavior at Room Temperature.....................................................................2 

3.2 Discharge at Subzero Temperatures (–20 °C and –40 °C)..............................................4 

3.3 Self-Heating of Cells During High Rate Discharge ........................................................7 

3.4 Discharge at 60 °C...........................................................................................................8 

3.5 Summary of Temperature Testing...................................................................................9 

3.6 Storage Life at Elevated Temperature (70 °C)..............................................................10 

3.7 Capacity Retention Under Different Cycling Conditions .............................................11 

3.8 High Pulsed-current Discharge Measurements .............................................................11 

3.9 Future Plans...................................................................................................................14 

4. Conclusions 14

Distribution 16 
iv 

List of Figures 

Figure 1. Configuration of Saft UHP cell during discharge. The cell was discharged inside 

an environmental chamber and the exterior temperature of the cell was monitored by a 

thermocouple..............................................................................................................................2 

Figure 2. Voltage and discharge capacity as a function of rate of discharge at 20 °C. The 

baseline capacity is ~5 Ah at room temperature........................................................................3 

Figure 3. Room temperature performance plotted as a specific energy versus specific power 

chart (Ragone plot). The data points are shown in red and a trend line is shown as a 

dotted black line.........................................................................................................................4 

Figure 4. Discharge capacity and voltage of Saft UHP cells as a function of temperature at 

fixed rate of 500 A. All cells were charged at 1C (5A) and 20 °C and discharged at 100C 

(500 A) at three temperatures; the baseline capacity is the capacity obtained using a 5 A 

discharge at 20 °C. .....................................................................................................................5 

Figure 5. Two cells in series configuration used for testing of discharge at –40 and –20 °C 

and 1000 A.................................................................................................................................6 

Figure 6. Discharge curve of two cells in series at –40 °C and 1000 A. The black curve is 

voltage and the red curve is exterior cell temperature. ..............................................................6 

Figure 7. Discharge curve of two cells in series at –20 °C and 1000 A. The black curve is 

voltage and the red curve is exterior cell temperature. ..............................................................7 

Figure 8. Self-heating of Saft UHP cell during 500 A, –40 °C discharge. .....................................7 

Figure 9. Self-heating of Saft UHP cell during 500 A, –20 °C discharge. .....................................8 

Figure 10. Discharge capacity at 60 °C as a function of discharge rate. ........................................8 

Figure 11. Specific energy and power density at 100C and 200C rates as a function of 

temperature. ...............................................................................................................................9 

Figure 12. Initial voltage drop at 100C and 200C as a function of temperature...........................10 

Figure 13. The temporary and permanent capacity loss of Saft UHP cells after periods of 7-

day storage at 70 °C. The 70°C cycling data are also plotted for comparison. ......................10 

Figure 14. The capacity retention of Saft UHP cells under different conditions: (1) charged 

at 1C (5 A) and then discharged at 200C (1000 A) at room temperature; (2) cycled at 1C 

(5 A) at high temperature and (3) cycled at 1C (5 A) at room temperature as benchmark. 

The cutoff range of 2.5 ~4.1 V corresponds to 100% of the designed depth-of-charge..........11 

Figure 15. Simplified schematic of the pulsed-current battery test circuit...................................12 

Figure 16. Pulsed-current battery evaluation stand.......................................................................12 

Figure 17. Pulsed response of two, VL5U cells connected in series. A peak current of 4840 

A with a pulse-width of 1.1 ms (full width at half maximum) is given by the blue trace 

and instantaneous cell voltages are given by the red and green traces. ...................................13 

Figure 18. Projected cell output voltage as a function of pulsed load currents. ...........................14 
v 

List of Tables 

Table 1. Characteristics of the Saft VL5U cells. ............................................................................1 

Table 2. Room temperature energy and power of Saft VL5U cell as a function of rate of 

discharge. ...................................................................................................................................4 

Table 3. Summary of rate and temperature testing.........................................................................9 
vi 

INTENTIONALLY LEFT BLANK. 
1 

1. Introduction 

The objective of this report is to evaluate the performance of Saft Ultra High Power (UHP) (Saft 

designation VL5U) lithium-ion cells and determine applicability for Army applications. This 

report includes the data and their analysis. The characteristics of the Saft VL5U cells are shown 

in table 1. 

Table 1. Characteristics of the Saft VL5U cells. 

Mass: ~350 g Dimensions: 15.23 cm length x 3.37 cm 

diameter cylindrical 

Volume: ~136 mL 

Capacity: ~5 Ah Energy: ~20 Wh (72 Joules) Avg. Discharge Voltage: ~3.8 V 

Energy Density: ~57 Wh/kg (163 Wh/liter) 

Chemistry of Electrodes: LiNi1-x-yCoxAlyO2 / Carbon 

Impedances: 

Via Pulse Discharge: 0.21-0.24 mΩ (see§3.7) 

AC-1000Hz: 0.3 mΩ (data provided by Saft) 

2 sec: 0.8 mΩ (data provided by Saft) 

2. Approach 

Saft UHP cells were subjected to high rate discharge testing at currents up to 1000 A (200C) 

using a Maccor battery cycler and pulse discharge testing using a capacitive load. In order to 

obtain the baseline capacity, cells were first equilibrated at 20 °C in an environmental chamber 

and then charged at a constant 5 A current to 4.1 V, followed by a constant voltage charge at 

4.1 V until the charging current was less than 0.1 A. We then measured the baseline capacity 

using a constant current discharge at 5 A to 2.5 V, and conducted temperature testing from 70 °C 

down to –40 °C. Prior to discharge, we determined a baseline performance of each cell by 

cycling at 1C (5 A) rate at room temperature, and after the low and high temperature discharge, 

we again cycled the cell at the 1C rate (room temperature) to determine if the performance had 

degraded as a result of the low/high temperature discharge. Additionally, we evaluated the cycle 
2 

life by cycling at a 1C rate at elevated temperature (70 °C) and at 200C at 20 °C. Figure 1 shows 

a cell as configured for discharge. A thermocouple was attached to the exterior of the cell by 

black electrical tape. 

Figure 1. Configuration of Saft UHP cell during discharge. 

The cell was discharged inside an environmental 

chamber and the exterior temperature of the cell was 

monitored by a thermocouple. 

3. Results

3.1 Discharge Behavior at Room Temperature 

The discharge capacity was evaluated at 500 A (100C) and 1000 A ( 200C). We set the cutoff 

voltage of the discharge at 2.5 V for 20 °C testing. We also obtained the discharge capacity at 

250 A at room temperature. Figure 2 shows the discharge capacity of a single cell as a function 

of the rate of discharge at 20 °C, normalized to 1C capacity. The cell is able to deliver about 

75% of the 1C (5 A) discharge capacity while discharging at the 200C (1000 A) rate. Clearly, 

the voltage is significantly lower at 1000 A; the average voltage during discharge at 1C is about 

3.6 V and at 200C around 3.1 V. 
3 

2

2.5

3

3.5

4

4.5

0 20 40 60 80 100

Percent of Baseline Capacity 

Cell Voltage (V)

5 A 

250 A

500 A

1000 A

Figure 2. Voltage and discharge capacity as a function of rate of discharge at 20 °C. 

The baseline capacity is ~5 Ah at room temperature. 

As a means to compare the data in the context of the current state of the art for rechargeable 

cells, we plotted the 20 °C discharge data on a Ragone-type plot of specific energy versus 

specific power. The baseline chart was provided courtesy of Saft. Figure 3 shows these data and 

table 2 tabulates them. In figure 3, the data points for the Saft UHP cells are shown as red 

rectangles and the rate of discharge is indicated next to each rectangle in red text as C-rate, 

C = 5 A. 
4 

Figure 3. Room temperature performance plotted as a specific energy versus specific power 

chart (Ragone plot). The data points are shown in red and a trend line is shown as a 

dotted black line. 

Note: The data point at 400C is from the IAT (University of Texas) data and the baseline chart is 

courtesy of Saft. 

Table 2. Room temperature energy and power of Saft VL5U cell as a function of rate of discharge. 

Rate Energy Power 

 Wh / kg Wh / liter kW / kg kW / liter 

1C (5 A constant) 57 146 0.052 0.13 

50C (250 A constant) 47 121 0.58 1.5 

100C (500 A constant) 42 108 4.7 12 

200C (1000 A constant) 36 93 8.7 22 

400C (2000 A constant)a 27 69 14 36 

a

 The data point at 400C is from the IAT (University of Texas) data. 

It is clear that the cell has been optimized for high specific power at the expense of specific 

energy. A lithium ion cell optimized for specific energy can attain close to 200 Wh /kg, but the 

specific power of such a cell is generally in the 10 to 100 W/kg range, which is much lower than 

the 14 kW/kg attained for the Saft UHP cell at 400C. 

3.2 Discharge at Subzero Temperatures (–20 °C and –40 °C) 

We next evaluated the performance at high rate and subzero temperature. The cutoff voltage was 

2 V for these subzero tests. At 1000 A, the cell voltage dropped below the cutoff voltage of 2 V 

and minimal discharge capacity was observed. At a 500 A discharge, the voltage drops very 
5 

close to 2 V at –40 °C, but remains above 2 V so we were able to obtain discharge capacities at 

three temperatures at this rate. Figure 4 shows these results. The baseline capacity refers to the 

1C capacity of each cell at room temperature. We observed an initial voltage drop at the subzero 

temperatures. The voltage recovers as the cell self-heats and the cells are able to attain close to 

the same discharge capacity at all three temperatures with a penalty in voltage at the subzero 

temperatures. As noted, discharge at –40 °C and –20 °C and 1000 A for a single cell led to an 

immediate drop to below the cutoff voltage of 2 V, the lower limit of our Maccor battery cycler; 

therefore, we then discharged two cells in series to overcome this equipment limitation. Figure 5 

shows the experimental setup. 

1

1.5

2

2.5

3

3.5

4

4.5

0 10 20 30 40 50 60 70 80 90

Percent of Baseline Capacity

Cell Voltage

T = -40 C 500 Amp

T = -20 C 500 Amp

T = 20C 500 Amp

Figure 4. Discharge capacity and voltage of Saft UHP cells as a function of 

temperature at fixed rate of 500 A. All cells were charged at 1C (5A) and 

20 °C and discharged at 100C (500 A) at three temperatures; the baseline 

capacity is the capacity obtained using a 5 A discharge at 20 °C. 
6 

Figure 5. Two cells in series configuration used for testing of discharge 

at –40 and –20 °C and 1000 A. 

The discharge curves of the two cells in series at –40 and –20 °C are shown in figures 6 and 7, 

respectively. At –40 °C, there is an immediate drop of about 3.6 to 4.5 V (2.25 V single cell 

equivalence). The voltage further drops to a minimum of 2.77 V (1.39 V single cell). The 

voltage begins to recover as self-heating of the cell occurs and reaches a maximum voltage of 

5.11 V (2.56 V single cell equivalence) before sloping back down as the cells are discharged. At 

–20 °C, there is an immediate drop of about 2.4 to 5.7 V (2.85 V single cell). The voltage further 

drops to a minimum of 4.4 V (2.2 V single cell). The voltage begins to recover as self-heating of 

the cell occurs and reaches a maximum voltage of 5.02 V (2.51 V single cell) before sloping 

back down as the cells are discharged. 

0

1

2

3

4

5

6

7

8

9

0 20 40 60 80 100

Percent of Baseline Capacity

Cell Voltage [V]

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

Ext. Cell Temperature [oC]

Figure 6. Discharge curve of two cells in series at –40 °C and 1000 A. The black 

curve is voltage and the red curve is exterior cell temperature. 
7 

0

1

2

3

4

5

6

7

8

9

0 20 40 60 80 100

Percent of Baseline Capacity

Cell Voltage [V]

-20

-15

-10

-5

0

5

Ext. Cell Temperature (o C)

Figure 7. Discharge curve of two cells in series at –20 °C and 1000 A. The black 

curve is voltage and the red curve is exterior cell temperature. 

3.3 Self-Heating of Cells During High Rate Discharge 

Figures 6 and 7 also show the heat rise during the 1000 A discharge at –20 °C and –40 °C, 

respectively. In figure 6, we observe a rise in temperature from –40 to –6 °C. In figure 7, 

we observe a rise in temperature from –20 to 1 °C. 

Figures 8 and 9 shows the heat rise during the 500 A discharge at –20 °C and –40 °C, 

respectively. In figure 8, we observe a rise in temperature from –40 to –10 °C. In figure 9, we 

observe a rise in temperature from –20 to 5 °C. 

1

1.5

2

2.5

3

3.5

4

0 10 20 30 40 50 60 70 80 90

Percent of Baseline Capacity 

Cell Voltage

-50

-40

-30

-20

-10

0

10

Ext.Cell Temp. (oC)

Figure 8. Self-heating of Saft UHP cell during 500 A, –40 °C discharge. 
8 

1

1.5

2

2.5

3

3.5

4

0 10 20 30 40 50 60 70 80 90

Percent of Baseline Capacity

Cell Voltage

-45

-35

-25

-15

-5

5

15

Ext. Cell Temp. (oC)

Figure 9. Self-heating of Saft UHP cell during 500 A, –20 °C discharge. 

3.4 Discharge at 60 °C 

The performance at 60 °C at multiple discharge rates and 5 A (1C) charging rate is shown in 

figure 10. The discharge currents used were 5 A, 250 A, 500 A, 600 A, 800 A, and 1000 A. 

At the elevated temperature, the cells are able to achieve close to 90% of the discharge capacity 

up to 1000 A. The voltage is reduced about 0.3 V for the 1000 A discharge compared to 

the 5 A discharge. 

2

2.5

3

3.5

4

4.5

0 10 20 30 40 50 60 70 80 90 100

Percent of Baseline Capacity

Voltage vs Li [V]

5 Amps

250 Amps

500 Amps

600 Amps

800 Amps

1000 Amps

Figure 10. Discharge capacity at 60 °C as a function of discharge rate. 
9 

3.5 Summary of Temperature Testing 

Temperature testing is summarized in table 3. The data at rates of 100C and 200C are plotted in 

figure 11 in order to show more clearly the effect of temperature on the specific power and 

specific energy of the cell. There is a clear drop in both specific energy and specific power as 

the temperature is decreased and the rate decreases. The effect of a drop in temperature from 

60 to –40 °C is more pronounced than the difference caused by the increase in rate. Figure 12 

illustrates the effect on voltage of change in temperature during discharge. There is a large drop 

in the voltage as the temperature decreases. 

Table 3. Summary of rate and temperature testing. 

Temp. Energy Density Power Density 

°C 

C Rate 

(1C = 5A) ΔVt=0 Wh/kg Wh/liter kW/kg kW/liter 

20 1C 0.0 57 146 0.055 0.14 

60 1C 0.0 55 141 0.052 0.13 

20 50C 0.1 47 121 0.58 1.5 

60 50C 0.1 52 134 2.5 6.4 

–40 100C 1.4 29 75 3.6 9.3 

–20 100C 0.9 29 75 3.8 9.8 

20 100C 0.3 42 108 4.7 12 

60 100C 0.1 49 126 4.9 13 

60 120C 0.2 48 123 5.9 15 

60 160C 0.2 46 118 7.7 20. 

–40 200C 1.8 26 67 5.9 15 

–20 200C 1.2 24 62 6.3 16 

20 200C 0.6 36 93 8.7 22 

60 200C 0.3 44 113 9.5 24 

0

10

20

30

40

50

60

-40 -20 0 20 40 60

Temperature (oC)

Energy Density (Wh / kg)

0

1

2

3

4

5

6

7

8

9

10

Power Density (kW / kg)

Energy Density (200C)

Energy Density (100C)

Power Density (200C)

Power Density (100C)

Figure 11. Specific energy and power density at 100C and 200C rates as a 

function of temperature.
10 

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

-40 -20 0 20 40 60

Temperature (oC)

ΔVt=0

200 C (1000A)

100 C (500A)

Figure 12. Initial voltage drop at 100C and 200C as a function of temperature. 

Clearly from these data shown in figures 11 and 12, there is room for improvement in the low 

temperature performance of these cells, though the decrease in performance at low temperature is 

probably not worse than state-of-the-art lithium ion cells. We would need comparable data from 

a similar cell for comparison.

3.6 Storage Life at Elevated Temperature (70 °C) 

We evaluated the storage life of the cells at 70 °C after 7 days of storage. Figure 13 shows those 

results. It seems the cell has high self-discharge rate. 

-20

0

20

40

60

80

100

120

0 2 4 6 8 10 12 14

Cycle Number

after 7 day storage at 70 oC

recovered 

capacity

continuous cycling at 70 oC

Figure 13. The temporary and permanent capacity loss of Saft UHP 

cells after periods of 7-day storage at 70 °C. The 70°C 

cycling data are also plotted for comparison. 
11 

The capacity will be almost entirely lost after 7-days storage. Although about 80% of nominal 

capacity can be recovered by recharging, the fade rate is even higher than 70 °C cycling. This 

test is incomplete and ongoing; more data from different cells are needed for confirmation. 

3.7 Capacity Retention Under Different Cycling Conditions 

We evaluated the capacity retention of the cells under different cycling conditions. The results 

(figure 14) suggest that a high discharge rate degrades the cell capacity faster than high 

temperature cycling does. The reason might be the buildup of interfacial resistance caused by 

electrolyte decomposition. The core temperature of the cell during the 1000 A discharge must be 

higher than 70 °C. Suggestion: An improved cell design with a better heat-dissipation 

mechanism might be able to significantly enhance the capacity retentions under the condition of 

high rate discharge. 

0

20

40

60

80

100

120

0 20 40 60 80 100

Cycle Number

Capacity Retention (%)

1000 A (200 C) Discharge at 25 oC

5 A (1C) cycling at 70 oC

5A (1C) cycling at 25 oC

Figure 14. The capacity retention of Saft UHP cells under different conditions: 

(1) charged at 1C (5 A) and then discharged at 200C (1000 A) at room 

temperature; (2) cycled at 1C (5 A) at high temperature and (3) cycled 

at 1C (5 A) at room temperature as benchmark. The cutoff range of 

2.5 ~4.1 V corresponds to 100% of the designed depth-of-charge. 

3.8 High Pulsed-current Discharge Measurements 

We assessed the high pulsed-current capability of the VL5U cells by using a capacitive load, as 

shown in the schematic of figure 15. We series-connected two, cells (DUT1 and DUT2) with the 

capacitor load using a thyristor. The capacitive load allowed us to tailor the pulse shape and 

ensure that a short-circuit condition was not inadvertently applied to the cells. Next, we 

connected 40 electrolytic capacitors (Cornell-Dubilier, CGS253U016R4C) in parallel using a 

pair of copper plates giving a total capacitance of approximately 1 F and an equivalent series 

resistance(ESR) of approximately 0.4 m. Once gated on, the thyristor (Vishay, 

ST333C08CFM0) completed the circuit allowing the capacitor bank to charge. Because the on-
12 

state voltage of the thyristor is approximately 3 V at 5000 A and, under load, the output voltage 

of the VL5U battery was expected drop from 4.1 V to 2.5 V, two cells were required. The 

resistor-capacitor snubber circuit connected across the thyristor prevented inadvertent dV/dt

triggering of the thyristor as the circuit was being assembled. Also, the capacitor bank was 

completely discharged through a 1 k resistor prior to each test. 

Figure 15. Simplified schematic of the pulsed-current battery 

test circuit. 

Figure 16 shows a photograph of the test stand. We mounted the two batteries-under-test on the 

capacitor load and mounted the thyristor at the opposing ends of the batteries. We used 

Rigowski current probes (PEM, CWT30) to measure the pulsed currents. 

Figure 16. Pulsed-current battery evaluation stand. 
13 

Figure 17 shows the responses of the VL5U cells taken at a case temperature of 18 °C. Prior to 

testing, the cells were fully charged. The green trace of figure 16 shows the instantaneous 

voltage of cell X835-40 during the first discharge pulse and the red trace shows the instantaneous 

voltage of cell X835-22 during the fourth discharge pulse. The blue trace is the cell current and 

shows a rise-time (10–90%) of 250 s. From this data, the minimum cell resistances are 

0.21 m and 0.24 m for cell X835-40 and X835-22, respectively. 

-1

0

1

2

3

4

5

-1 0 1 2 3 4

Time (ms)

Cell Voltage (V)

-1000

0

1000

2000

3000

4000

5000

Current (A)

X835-22

X835-40

Current

Figure 17. Pulsed response of two, VL5U cells connected in series. A peak current 

of 4840 A with a pulse-width of 1.1 ms (full width at half maximum) is 

given by the blue trace and instantaneous cell voltages are given by the 

red and green traces. 

Parasitic impedances limit the maximum peak currents obtainable in this test configuration. The 

capacitor bank has an ESR of approximately 0.4 m and the thyristor on-state resistance is 

approximately 0.5 m at high current levels. By matching experimental data with circuit 

simulations, we estimated the total circuit inductance to be 220 nH. Figure 18 gives the 

projected cell performance assuming an ideal short-circuit load. At an output voltage of 2 V, a 

pulsed output current of approximately 8750 A may be achieved. 
14 

0

1

2

3

4

5

0 2500 5000 7500 10000

Load current (A)

Output voltage (V)

Pulse width = 1 ms

Figure 18. Projected cell output voltage as a function of pulsed load currents. 

3.9 Future Plans 

Additional pulsed discharge cell characterizations are needed to better understand the VL5U 

lithium-ion cell technology. These characterizations may include testing over the military 

temperature range, maximum charging rate, and short-circuit survivability. Repeating select 

tests may be useful in order to assess cell to cell variability. 

4. Conclusions 

Our results show that the Saft UHP cells have a high rate capability with about 80% of baseline 

capacity (5 A, 1C rate, room temperature) accessed at a 1000 A (200C) rate of discharge—the 

voltage was depressed during the high rate discharge by about 0.6 V. At low temperatures, 

–20 °C and –40 °C, we obtained about 80% of the baseline capacity at a 500 A (100C) rate; 

however, the voltage was further depressed to a remaining voltage below 3 V during the entire 

discharge. At –20 °C, the voltage was depressed by up to 1 V relative to the room temperature 

discharge during the initial time of discharge and at –40 °C, the voltage was depressed by up to 

1.7 V during the initial time of discharge. Storage life testing at 70 °C suggests a high rate of 

self-discharge. Cycling at different conditions suggests that high rate cycling degrades the cell 

faster than high temperature cycling, which implies that significant self-heating occurs at high 

rates of discharge. Measurements of cells tested at –40 °C and –20 °C showed an external cell 

temperature of –10 °C and 5 °C, respectively, at the end of discharge. The core cell temperatures 

were clearly higher.An improved cell design with a better heat-dissipation mechanism might be 
15 

able to significantly enhance the capacity retention under the condition of high rate discharge. 

The storage life is not as good as other versions of cells; improvement is needed. Finally, pulse 

discharge testing using a capacitive load showed that, at an output voltage of 2 V, a pulsed 

current of 8750 A may be achieved. 
16 

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 ATTN DTIC OCP 

 8725 JOHN J KINGMAN RD STE 0944 

 FT BELVOIR VA 22060-6218 

 1 DARPA 

 ATTN IXO S WELBY 

 3701 N FAIRFAX DR 

 ARLINGTON VA 22203-1714 

 1 CD OFC OF THE SECY OF DEFNS 

 ATTN ODDRE (R&AT) 

 THE PENTAGON 

 WASHINGTON DC 20301-3080 

 1 US ARMY RSRCH DEV AND ENGRG 

 CMND 

 ARMAMENT RSRCH DEV AND 

 ENGRG CTR 

 ARMAMENT ENGRG AND 

 TECHNLGY CTR 

 ATTN AMSRD AAR AEF T J MATTS 

 BLDG 305 

 ABERDEEN PROVING GROUND MD 

 21005-5001 

 1 PM TIMS, PROFILER (MMS-P) 

 AN/TMQ-52 

 ATTN B GRIFFIES 

 BUILDING 563 

 FT MONMOUTH NJ 07703 

 1 US ARMY INFO SYS ENGRG CMND 

 ATTN AMSEL IE TD F JENIA 

 FT HUACHUCA AZ 85613-5300 

 1 COMMANDER 

 US ARMY RDECOM 

 ATTN AMSRD AMR 

 W C MCCORKLE 

 5400 FOWLER RD 

 REDSTONE ARSENAL AL 35898-5000 

 1 US ARMY TANK-AUTOMOTIVE 

 RSRCH DEVEL AND ENG CTR 

 ATTN S GARGIES 

 6501 E. 11 MILE RD BLDG 312 

 MS 121 WARREN MI 

 WARREN, MI 48397 

No. of 

Copies Organization 

 1 US GOVERNMENT PRINT OFF 

 DEPOSITORY RECEIVING SECTION 

 ATTN MAIL STOP IDAD J TATE 

 732 NORTH CAPITOL ST NW 

 WASHINGTON DC 20402 

 1 US ARMY RSRCH LAB 

 ATTN AMSRD ARL CI OK TP 

 TECHL LIB T LANDFRIED 

 BLDG 4600 

 ABERDEEN PROVING GROUND MD 

 21005-5066 

 1 DIRECTOR 

 US ARMY RSRCH LAB 

 ATTN AMSRD ARL RO EV 

 W D BACH 

 PO BOX 12211 

 RESEARCH TRIANGLE PARK NC 

 27709 

 12 US ARMY RSRCH LAB 

 ATTN AMSRD ARL SE DC C XU 

 ATTN AMSRD ARL CI OK PE 

 TECHL PUB 

 ATTN AMSRD ARL CI OK TL 

 TECHL LIB 

 ATTN AMSRD ARL SE DC W BEHL 

 ATTN AMSRD ARL SE DC J ALLEN 

 ATTN AMSRD ARL SE DC J READ 

 ATTN AMSRD ARL SE DC 

 J WOLFENSTINE 

 ATTN AMSRD ARL SE DC R JOW 

 ATTN AMSRD ARL SE DP 

 D PORSCHET 

 ATTN AMSRD ARL SE DP T SALEM 

 ATTN AMSRD ARL SE DP 

 W TIPTON 

 ATTN IMNE ALC HR 

 MAIL & RECORDS MGMT 

 ADELPHI MD 20783-1197 

TOTAL: 23 (1 ELEC, 1 CD, 21 HCS)