Review of Previous Tests

3. Review of Previous Tests • Primary battery failure mode • Ignition intensity • Effect of fire size • Battery flammability by type and brand • CR2, PL 123A, Duracell, Panasonic • Effect of packing material • Cargo liner integrity

4. Review of Previous Tests • Halon suppression effectiveness • Lithium Ion rechargeable battery • Laptop computer • Oven tests • Self ignition temperature • Explosion • Pressure pulse from battery ignition

5. Results- Battery Failure Mode • 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

6. Results-Multiple Battery Failure Mode • 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

7. Results-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 • The packaging kept the batteries together, heat from the fire fused them together. • Once ignited, the fire propagated through all batteries.

8. Results- Lithium Ion Rechargeable Laptop Battery • 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

9. Results- Halon Supression • 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.

10. Results- Cargo Liner Integrity • Three groups of four batteries were arranged so that the torching electrolyte and spraying molten lithium would directly impinge on liner. • 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

11. Results- Oven Auto-Ignition Temperature Tests • Duracell CR2 • Average ignition temperaure: 487 Deg F • Average temperature rise in oven due to battery ignition: 524 Deg • Panasonic PL123A batteries. • Average ignition temperature: 466 Deg F • Average temperature rise in oven due to battery ignition: 514 DegF

12. Results- Explosion Tests • Cargo compartment integrity can be breached at about 1 psi • The pressure rise due to just 4 burning lithium batteries can exceed 1 psi in a 10 cubic meter container

15. CONCLUSIONS • The temperatures found in a suppressed smoldering cargo fire are sufficient to ignite a primary lithium battery • The pressure rise due to battery ignition is sufficient to compromise the integrity of a cargo compartment

16. Current Work • Lithium-ion rechargeable batteries • Literature search on battery types • Evaluation of existing flammability data • Effect of charge state on flammability • In house testing as required • Coordination of efforts with the Lithium Battery Technical/Safety Group