This chapter describes the basic principles of electrochemical energy storage and discusses three important types of system: rechargeable batteries, fuel cells and flow batteries. A rechargeable battery consists of one or more electrochemical cells in series. . Electrical energy storage (EES) systems constitute an essential element in the development of sustainable energy technologies. These devices are critical enabling technologies for renewable energy; energy management, conservation, and storage; pollution control/monitoring; and greenhouse gas reduction.
