Conclusion of MFF Battery Development. Eugene Marquis NSWCDD-G34 Fuze Branch

Transcription

1 Conclusion of MFF Battery Development Eugene Marquis NSWCDD-G34 Fuze Branch 1

2 Lead is Dead Objective Develop a replacement battery for the MK 44 Lead-Acid Liquid-Reserve Battery for use in the Navy s Multi-Function Fuze, MK 419 Lithium has more voltage per cell than Lead Lithium s startup characteristics are different than Lead 2

3 3 Battery Options #1: Modify Alliant MOFA battery Increased voltage & current draw Larger diameter requires mechanical modification to fuze #2: Modify Thales UA-6275 battery Increased voltage & current draw Fits within MK 44 battery s envelope Issue: Unknown susceptibility to rough handling - Not a safety concern #3: Modify Diehl/EP Mod 597 battery Increased voltage & current draw Fits within MK 44 battery s envelope 3

4 Performance Requirements Requirements for MFF Battery Current Requirement Time Voltage Current (msec) (v) (ma) sec Voltage (v) Voltage Requirement Current (ma) Risetime was never an issue with lead acid batteries Time (msec) 4

5 Testing: MFF Load Circuit Voltage is measured across the battery Voltage drop across diode steering circuit Current is measure across 0.5 Ω resistor Constant current draw at 12.5V or more Voltage regulator with a fixed resistor on output Battery comes up under a 60 ma load - R3 450 ma load is switched in at 100ms - R2 Voltage Current VR R2 R3 5

6 1st Approach: ATK 2 Electrolyte Studies were conducted to investigate ways to easily improve risetime Results showed MOFA electrolyte was best for risetime Built 80 batteries with 5x2 configuration Based on MOFA battery design (3x2 configuration) 5x2 configuration (+) 3x2 configuration (+) (-) (-) 6

7 MOFA MFF M782 - MOFA 3x2 configuration 325mA current draw 5.6V battery voltage MK MFF 5x2 configuration 450mA current draw 12.5V battery voltage Added 2 more cells per parallel stack 7

8 Fitting into MK 44 Alliant Ø 1.50 Electronics flex print lays on top of flat 0.86 MK 44 Ø

9 Typical ATK Risetime 70 F Current draw (scale 0-100mA) 60mA 15.5v 13.9v Battery voltage (scale v) 60mA 450mA Current draw (scale 0-500mA) Time zero pulse 12msec/ division 9

10 Conclusion of 1 st Approach: ATK 36 Alliant Batteries tested Risetime met in batteries that did not show signs of excessive inner cell shorting Typical CVT Mission Life would be met Temp. ( F) # of units tested Rise Time to 12.5 Volts (msec) AVERAGE STAND. DEV 50ms Voltage after load Pass Fail Pass Fail 20 F F F F Total Batteries that exhibited shorting were not included in risetime average 10

11 2nd Approach: Thales Approach #2: Modified Thales battery Modified UA-6275/821 4x2 configuration Built 80 batteries UA-6295/521 5x2 configuration Glass ampoule Unknown susceptibility to breakage Not a safety issue but affects long term reliability 11

12 Fitting into MK 44 Thales & Diehl/EP Ø32 Ø21 MK Ø

13 Conclusion of 2 nd Approach: Thales Meets Fit, Form, & Function of MK 44 Very limited mechanical repackaging of fuze Rise time is very close to MK 44 & consistent across temperature range Meets mission life requirement Temp. ( F) # of units tested Rise Time to 12.5 Volts (msec) AVERAGE STAND. DEV 50ms Voltage after load Pass Fail Pass Fail 20 F F F * F TOTAL *missed by 1.6V 13

14 Diehl/Eagle-Picher 597 3rd Approach: Diehl/EP Recently enter US market Capable of 5x2 configuration 4x2 design tested Glass ampoule It should not be susceptible to breakage due to breaker design BattAnim_neu.mov 14

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16 Conclusion of 3 rd Approach: Diehl/Eagle Picher Meets Fit, Form, & Function of MK 44 Very limited mechanical repackaging of fuze Rise time same as MK 44 Scaling of 4x2 battery suggests that 5x2 would meet risetime requirements Testing of D/EP 5x2 for Mission Life Requirement Temp. ( F) # of units tested Rise Time to 12.5 Volts (msec) AVERAGE STAND. DEV 50ms Voltage after load Pass Fail Pass Fail 20 F F 0 70 F F TOTAL Pass/Fail scaled to 4x2 configuration 16

17 Conclusions Alliant Typical CVT Mission Life met Investigate inner cell shorting on top stack Thales Good rise time and consistent across all temperatures Glass ampule susceptible to breakage Past experience with glass ampules show reduced reliability Diehl/Eagle-Picher Testing of 4x2 battery suggests a 5x2 can perform as well as MK 44 2 nd source & potentially improved reliability against accidental activation during storage & handling 17