ABSTRACT
This chapter explains the term 'capacity' and 'discharge rate', as they apply to cells and batteries. It describes the function of an electrochemical cell and also explains the difference between a primary cell and a secondary cell. The chapter explores the chemical process by which a simple Voltaic cell is able to separate charge in order to provide a potential difference between its plates and describes the construction of a Dry Leclanche cell. It discusses how a lead-acid cell's relative density is a guide to its state of charge and also explores the disadvantages of nickel-cadmium cells, and how these are overcome using lithium-ion cells. The chapter provides how a fuel cell differs from a chemical cell and outlines the basic principle of operation of a hydrogen/oxygen fuel cell. Nickel-cadmium cells are re-energisable cells that use nickel oxide hydroxide and metallic cadmium foil as their positive and negative electrodes, and potassium hydroxide as an electrolyte.
