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Thermal Hazard Technology. THT is the Original Company for ARC & Battery pioneered ARC for over 20 years Pioneered Li Battery for over 10 years Sales, service, support worldwide. Li Batter y Companies with THT ARC. Worldwide – Major Users
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Thermal Hazard Technology THT is the Original Company for ARC & Battery pioneered ARC for over 20 years Pioneered Li Battery for over 10 years Sales, service, support worldwide
Li Battery Companies with THT ARC Worldwide – Major Users Sony, Sanyo, Toshiba, Mitsubishi, Panasonic, GS Battery, BAK, Lishen, ATL Samsung, LG NASA, Penn State Univ, GM-Delphi, Motorola, Sandia National Labs, Duracell Nokia, SAFT, Ultralife, Varta, Valence
Safety Issues with Li Batteries Thermal properties; effect of heat on batteries effect of heat produced by batteries Well known – temperature exposure, overcharge / discharge, shorting Heard details of such safety details, reference to in-house empirical tests, DSC, UL 150C Hot box, and some ARC data
Safety Issues with Li Batteries The Accelerating Rate Calorimeter has become accepted as a key instrument for assessing the thermal hazard potential of Li Batteries Unlike other tests… it is not empirical Quantifies the thermal effect Gives a ‘worst case’ assessment Can test batteries of ‘any size’ Different labs anywhere can compare data
Safety Issues with Li Batteries Evaluate the reactions in any type of battery component, for their stability and safety Evaluate made batteries under any state of charge, for their stability and safety Evaluate effect of abuse testing on battery safety, shorting over-voltage testing Evaluate batteries when charged, discharged, cycled for their thermal properties, to get life cycle and electrothermal efficiency information
Using the ARC with Battery Materials anode cathode electrolyte SEI…… fresh or after making / charging / cycling…. as per the work of Jeff Dahn
Data shows onset and temperature and pressure increase under worst case conditions
Data shows onset, heat generation at every temperature, temp rise is proportional to heat of reaction, slope is proportional to activation energy, shows complexity of decomposition, all under worst case conditions
Data varies with charge / age. Three regions of exothermicity, interface, anode and cathode reactions – but an 18650 will progress to explosion
Reaction Sequence in Li-Ion Battery exothermicity 1st reaction – SEI 2nd reaction – Anode (MCMB) 3rd reaction – cathode (Li Spinel) Electrolyte – decomposition from 80oC Electrolyte – very flammable Lithiated MCMB –air flammable hazard Delithiated spinel – shock sensitive explosive hazard
Li-Ion 18650 – Battery Safety Onset of Exothermic Reaction Overdischarged (2.0V) Onset = 110-120oC Fully Discharged (2.6V) Onset = 110-120oC Partially Charged (3.6) Onset = 90-100oC Fully Charged (4.2V) Onset = 70-90oC Overcharged (4.8V) Onset = 30-50oC Overcharged (>5V) Onset = ambient
Mobile phone Li-ion prismatic Shorting leads runaway
Lithium Iron Disulphide AA size Shorting does not lead to runaway – note gap in data
Gibbs free energy efficiency Battery performance factor Q – charge capacity A – surface area m - mass
Cycle Process ET ET (%) 2 Discharge 0.7865 42.5 3 Charge 0.3341 4 Discharge 0.7926 41.8 5 Charge 0.3316 6 Discharge 0.8055 41.1 7 Charge 0.3311 Battery performance and Gibbs free energy efficiency results