Introduction: Batteries are already ubiquitous in everyday life, surrounded as we are by countless electronic devices powered by them. Helped by this mass adoption in consumer electronic devices, batteries are now spreading into other, larger scale applications, key amongst them electric vehicles (EVs) and stationary battery electricity storage systems (BESSs). Content: This report provides a brief introduction to BESSs. We cover the technology and its applications, as well as historical, current and potential future deployment. Here is the outline for the content of this report: Introduction Battery Basics Battery Electricity Storage Systems (BESSs) Lithium-ion Batteries, Types and its Applications BESS Applications and Use Cases [...]