  Book chapter in "Thermodynamics in the quantum regime - Recent Progress and
Outlook" -- This chapter is a survey of the published literature on quantum
batteries -- ensembles of non-degenerate quantum systems on which energy can be
deposited, and from which work can be extracted. A pedagogical approach is used
to familiarize the reader with the main results obtained in this field,
starting from simple examples and proceeding with in-depth analysis. An outlook
for the field and future developments are discussed at the end of the chapter.
