The book addresses the problem of real-time diagnosis of electrical energy storage systems used in the automotive industry. Li-ion technology was chosen as backup solution for electrical energy storage for an application of electrical brake for cars. Given the importance of application supplied by these batteries, an accurate and reliable algorithm for real-time diagnosis of these batteries is necessary. Another issue addressed is that of thermal management of these types of batteries. Knowing that Li-ion technology, which underpins the operation of these batteries, has a fairly narrow temperature range: below -20°C batteries cannot provide electricity and over 60°C rapid deterioration issue implies risk with potentially dangerous consequences as warns manufacturer, solutions to bring these batteries in the range of temperature values that ensure optimal operation without affecting their life time are compulsory to be implemented.