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LITHIUM BATTERY FIRE TESTS. Harry Webster FAA William J Hughes Technical Center Harry.Webster@tc.faa.gov. BACKGROUND. Aircraft Cargo Fire April 99 (LAX) Dropped pallet of batteries on ramp caught fire No external ignition source No current limitation on number of batteries shipped.
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LITHIUM BATTERY FIRE TESTS Harry Webster FAA William J Hughes Technical Center Harry.Webster@tc.faa.gov
BACKGROUND • Aircraft Cargo Fire • April 99 (LAX) • Dropped pallet of batteries on ramp caught fire • No external ignition source • No current limitation on number of batteries shipped
IS THERE A NEED FOR REGULATION? • Develop a test methodology to determine: • Number of batteries or pounds of lithium that poses a threat to aircraft safety • Effect of battery number on duration and intensity of fire • Variation due to battery type • Packaging effects (improved type if needed) • Lithium interaction with Halon 1301
TEST FACILITIES • 64 CUBIC FOOT TEST CHAMBER • Measured Halon 1301 concentration • Video port • temperature measurement • heat flux measurement • various heat / fire sources
TEST FACILITES (2) • TC-10 CARGO COMPARTMENT • Full Scale Tests • Fire Detection • Halon 1301- 5% initial, 3% suppression • Temperature/agent concentration instrumentation
PRELIMINARY TESTS • Single battery tests by Dave Blake • Alcohol fire source • flammable electrolyte venting • High intensity lithium fire • flare type and explosive combustion • some visual indication of interaction between lithium fire and Halon
APPROACH • Determine the maximum amount of lithium that can be safely controlled in a cargo compartment fire by the on board suppression system • 5%/3% Halon 1301 • increment battery number until no longer controllable
APPROACH (2) • Investigate the effect of packaging(if needed) • Ignition sources / Fire intensity need for battery ignition • Repeat series for distinct battery types • Expand testing to include full scale tests (if needed)
PRODUCTS • Data to support a rule making regarding air shipping of lithium batteries • maximum number of batteries and/or pounds of lithium • packaging requirements (if needed)
TEST SERIES • 64 CUBIC FOOT TEST: • Alcohol Fire Baseline tests: • 20.6 square inch fire with 50 ml 1-Propanol • 90.7 square inch fire with 220 ml 1-Propanol • CR2 battery increment tests • 1, 2, 4, 8, 16, 32, 64 and 128 batteries • Packaging effects • Cargo liner integrity tests
Preliminary Test Results • CR2 Battery Failure Mode: • When exposed to an alcohol fire: Battery initially vents electrolyte gas, usually at the positive electrode. The electrolyte gas “torches” with a red flame and with some propulsive force. After the electrolyte burns off, the molten lithium then burns explosively, spraying white hot lithium through the vent hole. Unrestrained, the battery can bounce around the test fixture
CR2 Battery Tests • Tests were run with 1, 2, 4, 8, 16, 32, 64, and 128 batteries • The ignition of a single battery was sufficient to ignite the adjacent batteries • The peak temperature generated by the battery fires did not go up significantly with the number of batteries. • The duration of the peak temperature increased with the number of batteries
CR2 Battery Tests • Peak temperatures ranged from 1100 to 1600 DegF • Packaging effects. • 32, 64, and 128 batteries were placed in cardboard packaging similar to the shipping boxes • Packaging delayed the ignition of the batteries by 30-60 seconds
CR2 Battery Tests • Packaging effects • The packaging kept the batteries together, heat from the fire fused them together. • Once ignited, the fire propagated through all batteries. • Cargo Liner Integrity Tests • Three groups of four batteries were arranged so that the torching electrolyte and spraying molten lithium would directly impinge on liner.
CR2 Battery Tests • Cargo Liner Integrity Tests • Thin wall cargo liner • The battery fire ignited the resin • The torching electrolyte penetrated the liner • The molten lithium penetrated the liner • Thick wall cargo liner • The liner was able to contain the fire • Face of liner charred, Fiberglas exposed, but not penetrated
Future Tests • 64 Cubic Foot Box Tests: • Effect of Halon 1301 suppression • Addition primary battery types • Lithium Ion batteries • Full Scale Cargo Tests • Validate data from 64 FT3 tests
Halon Suppression Tests • Halon Concentration Tests • The 64 cubic foot test facility was fitted with a Halon 1301 distribution system • Facility fitted with a Halon concentration analyzer • 1.23 lbs. of 1301 required to achieve 5% concentration • Facility modified to achieve acceptable leakage rates
Halon 1301 / Lithium Battery Fire Test Conditions • Tests were conducted with 4,8,16 and 32 Sanyo CR2 batteries suspended over 90.7 square inch fire pan with 220 ml 1-Propanol • Alcohol fire was ignited and allowed to burn until at least one battery ignited • Halon 1301 was discharged at the point of battery ignition-extinguishing the alcohol fire.
Halon 1301 Suppression Results • Alcohol fire immediately extinguished • Battery fires continued to propagate until all batteries were consumed • Vented electrolyte fires were red in color • Normally white molten lithium sparks appeared red in color • Box temperature profiles lower due to extinguished alcohol fire.
Halon 1301 Suppression Conclusions • 1301 has no effect on the intensity and propagation of the lithium battery fire • The red color of the vented electrolyte flame indicates a chemical reaction with the 1301 • The red color of the molten lithium sparks indicated a chemical reaction with the 1301 • 1301 has no suppression effect on the lithium battery fire
PL123 A Battery Tests • Two brands of PL123 A batteries were tested • Duracell • 1,4,8 and 16 batteries tested • Halon suppression on second 16 battery test • Panasonic • 4,8,12 and 16 batteries tested
Pl 123 A Test Results • Duracell Tests: • Batteries behaved very similar to CR2 type • Initial electrolyte venting/flames followed by lithium sparks • Halon suppression had no effect on battery fire propagation or intensity • Larger battery size produced more intense fire than CR2
Pl 123 A Test Results • Panasonic Tests • Batteries were much more explosive than the Duracell brand • Most batteries vented in a controlled manner, but several blew the entire top off the battery • Pressure pulse when this occurred was enough to blow the clamp off of the viewing door and deform the screen used to suspend the batteries over the alcohol fire
Lithium -Ion Battery Tests • Laptop Rechargeable Battery • 14.4 Volt Compaq Presario Li-ion • Two tests were conducted suspending the batteries over the 90.7 square inch fire pan with 220 ml 1-Propanol • Fire load varied to obtain longer burn time: • 125 ml alcohol: 3.5 minutes • 250 ml alcohol: 6.5 minutes
Lithium Ion Battery Test Results • 3.5 minute fire exposure • Battery did not catch fire • Plastic case deformed, melted, case became hard and brittle • No self sustaining fire • 6.5 minute fire exposure • Similar results to 3.5 except: • some small venting, with small sparks
Conclusions • A relatively small fire source is sufficient start a lithium battery fire • The ignition of a single battery produces enough heat to ignite adjacent batteries • Halon 1301 is ineffective in suppressing a lithium battery fire • Batteries of the same type but from different manufacturers exhibit varying flammability characteristics
Conclusions • Halon 1301 chemically interacts with the burning lithium and electrolyte-with no effect on fire intensity • Cargo liner is vulnerable to penetration by molten lithium • Batteries fuse together when exposed to flame, promoting propagation between batteries
Future Tests • Install pressure transducer to measure magnitude of pressure pulse • Investigate other types/brands of lithium batteries • Determine effectiveness of alternate suppression agents • Full scale cargo compartment tests