The deployment of stationary battery energy storage system continues to grow as renewable energy systems are integrated into the electricity grid. Research on battery systems covering areas of system optimization, battery management system, grid integration of BESS, etc., have transformed the pattern of energy use and storage resulting in more energy efficient and sustainable energy systems.

This thesis explores the thermal dynamics of subterranean battery energy storage systems for residential applications. Residential battery installations have brought up concerns surrounding safety, pollution, and structural footprint, which could hinder a widespread adoption of stationary battery storage systems for increased electrification. Burying batteries underground addresses these concerns. While previous research has focused above-ground battery installations, this study explores the potential of utilizing the ground as an infinite heat sink or storage for thermal management. The impact of soil temperatures, battery geometry and soil thermal properties on battery performance are analyzed through thermal modelling and laboratory experiments.

The result indicates that the thermal response of the battery and its surrounding soil is significantly influenced by the battery operation signal and the thermal properties. This is reflected in the variation peak battery temperature and the heating or cooling rate of the battery. The ground temperature has a linear influence on the peak battery temperatures but has no impact on the rate of heat dissipation. Variation of the geometry may create or reduce the heat pathways, which influences the temperature of the system minimally. For example, a four-sided battery pack creates a wider area for heat diffusion, and the predicted battery temperature peaks at 67 oC for an aggressive signal, which is a 5 oC less than the result of a six-sided battery pack.