"This book covers an overview and applications of the thermal storage systems used in batteries for the electric automotive industry such as in electric vehicles, thermal storage system in smart grid systems, thermal harvesting for battery-less use for wireless sensor networks, thermo-electric generators and biomedical sensing. The thermal storage system can be used to harvest energy for implementation of battery-less, zero-maintenance and place-and-forget electronic systems. This book has been prepared for the needs of those who seek an application on developing the thermal system. The choice of material is guided by the basic objective of making an engineer or student capable of dealing with thermal system design. The book can be used as reference book for undergraduate and postgraduate students in the area of thermal system overview, design and applications. Lithium iron phosphate (LiFePO4) batteries have gained significant traction in the electric automotive industry in the recent years mainly due to their high safety performance, flat voltage profile and low cost. Although LiFePO4 batteries have excellent thermal stability, they still suffer from thermal runaway like other lithium-ion type cells. Thermal volatility is a major drawback in the lithium-ion and sufficient knowledge of the thermal distribution and heat generation of the LiFePO4 battery is necessary to avoid catastrophic thermal failure. The first chapter details the thermal analysis of a LiFePO4 battery cell with a latent heat thermal cooling wrap. The model has been developed as a tool to study the cooling effects of the wrap on the battery cell during discharging. The proposed latent heat storage based battery cooling wrap is used to passively manage the heat produced by the cell and absorbing and maintaining the battery temperature within operational temperatures and below thermal runaway temperature. Thermal energy storage (TES) is another important concept of the smart grid systems. For non-renewable, the benefit of TES systems is the improvement of the generation performance by supporting the energy demand during peak hours. Also, TES is often able to improve the system efficiency in a way that is more energy and cost effective. The best-known method for thermal energy storage is by utilizing the latent heat of fusion of energy storage material known as phase change materials (PCM). TES systems are classified into two main categories such as sensible and latent heat storage. An overview of the research on performance improvement are also delineated. Hence, the thermal energy harvesting has indeed gained attention in the last decade due to its promising possibilities in area such as wireless sensor networks (WSN) for wide range of IoT (Internet of Things) applications. Thermal energy scavenging from waste heat can enable implementation of battery-less, zero-maintenance and place-and-forget electronic systems. Scavenging energy from the temperature difference between human body heat and ambiance is an attractive solution for powering wearables for continuous health monitoring, biomedical sensing and body area sensor networks (BASN). The low energy efficiency and low voltage output of the thermo-electric generators (TEG) pose challenges to the deployment of industry ready powering systems"--