Abstract

This thesis explains the design of equipment and the experimental procedure for thermal treatment of lithium-ion batteries for the purpose of low-cost materials recycling. Conditions used were between 150 ℃ and 425 ℃, involving different atmospheric conditions and treatment durations. The battery samples were processed through a sieve shaker device. Mass loss during the heat treatment, and separation of the battery through sieving was used to analyze the effect of the treatments on separability of black mass from the batteries. Additionally, internal battery temperature was measured and compared to real average furnace temperature to monitor thermal runaway. Testing showed minimal increase in mass loss above 350 ℃, but separation of fine fraction black mass increased consistently with temperature, beginning at 350 ℃ and peaking at 400 ℃ or above. Between nitrogen, pyrolysis, and carbon dioxide conditions, the highest black mass separation was found in the nitrogen treatment. Maximum mass loss during heat treatments, just under 15%, was consistent with the expected electrolyte solvent evaporation and separator decomposition. A treatment duration of 20 minutes is found to be too short to create good mass loss and black mass retrieval, but little improvement is made with durations above 45 minutes. The maximum retrieval of fine fraction was close to 25% of the treated battery weight. Battery internal temperatures display clear evidence of thermal runaway by 350 ℃, with evidence of some thermal runaway beginning as low as 200 ℃. Internal battery temperatures during thermal runaway at treatment temperatures of 350 ℃ and above increased linearly with treatment temperature at an average offset close to 120 ℃. Maximum battery internal temperature at the highest treatment temperature of 425 ℃ reached just above 600 ℃.

Degree

College and Department

Ira A. Fulton College of Engineering; Chemical Engineering

Rights

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