"Primary and secondary batteries contain the same basic structure of a cathode, an anode, an electrolyte for moving charge between the terminals, and a means to separate them. Secondary cells are distinguished by the type of rechargeable chemistry employed, such as nickel-cadmium or lithium-polymer, or solid-state thin film.
Although the energy-harvesting-system designer may not be focused on cell structure and chemistry, it will be helpful to develop a working knowledge of the various technologies since it is the cell chemistry that determines all of the battery performance metrics and limits. (For more details and explanation about storage battery performance metrics consult the Energy Harvesting TechZone article, Understanding Storage Battery Specifications for Energy Harvesting.)"
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