Thermal Instability Assessment of De-lithiated Cathode Materials Reacted with Organic Carbonates
| Autor: | YU, HAO-HSIN, 余浩欣 |
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| Rok vydání: | 2017 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 105 Fire and explosion accidents of lithium-ion battery occurred frequently though it becomes the most widely used renewable energy source. One of the main reasons is due to the exothermic thermal runaway reaction between the de-lithiated cathode materials and electrolytes. A confinement test equipment according to ASME E476 was utilized to investigate the thermal behaviors. Two types of cathode materials, i.e., lithium nickel manganese cobalt oxide, namely, LiNi1/3Mn1/3Co1/3O2 (NMC333) and LiNi0.5Mn0.3Co0.2O2 (NMC532).Another type of cathode material is lithium nickel aluminum oxide, namely, LiNi0.8Co0.15Al0.05O2 (NCA).They were firstly de-lithiated chemically. Electrolytes, namely, ethylene carbonate (EC), mixtures of EC/DEC(diethyl carbonate) and EC/DMC(dimethyl carbonate) with the ratio of 1：1, were then reacted with de-lithiated cathode materials. Thermal kinetic data such as exothermic onset temperature, maximum self-heating rate and exothermic maximum temperature were measured and compared. Heating rate is selected to be 1 ℃ min-1 in programmatic ramp up to 450℃ for the purpose of triggering thermal runaway inside the test cell. Results indicate that relatively low onset temperatures around 60℃~70℃ occurred while de-lithiated cathode materials reacting with EC and LixNMC532 turns out to have the lowest onset temperature. On the other hand, the onset temperatures raised to around 60℃~100℃ while reacting with the mixtures of either EC/DEC or EC/DMC. These phenomena suggest that for inherently safer design, EC electrolyte material should not be used solely due to its highly incompatible with cathode materials of lithium nickel manganese cobalt oxide. Nonetheless thermal instability and thermal runaway severity of lithium-ion battery can be mitigated while using hybrid mixtures of EC/DEC and EC/DMC instead of EC. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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