This thesis presents a risk analysis of thermal runaway of electric vehicles in closed spaces. The use of electric vehicles has increased significantly in recent years due to their environmental benefits. However, the lithium-ion batteries used in these vehicles have the potential to cause thermal runaway, resulting in fires that can be difficult to extinguish. This risk is amplified when electric vehicles are stored or charged in closed spaces, such as underground parking garages or warehouses. This thesis investigates the potential risk of thermal runaway events occurring in electric vehicles (EVs) in closed spaces, such as garages or tunnels. Thermal runaway is a phenomenon where the battery cells in an EV rapidly heat up and release flammable gases, leading to a self-sustaining fire.