Primary and Secondary Batteries

A battery is a device that is used to store electrical energy in a solar system. The energy stored in a battery also called the charge capacity is given in Ampere Hours (AH). A 10AH battery can give 1A for 10hours or 2A for 5hours or any other combination. The voltage of the battery together with its charge capacity defines the energy stored in Watt Hours (WH) e.g. a 10AH battery operating at 12V can store 120WH of electrical energy. The energy storage capacity of a battery depends upon the type and weight of the material used. An important metric in this regard is the energy storage capacity per kilogram of material (WH/kg).

Batteries are composed of two terminals called anode (negative) and cathode (positive) and an electrolyte. Based upon the materials used in construction of batteries they can be classified into primary or secondary.

Primary and Seconday Battery Types

 Primary Cells or Batteries

• Not rechargeable
• Electrolyte is contained by absorbent (dry cell)
• Convenient, inexpensive, lightweight
• Used for portable electronics and electric devices, lighting, etc
• Good shelf life
• High energy density
• No or low maintenance
• Usually small scale power

Secondary Cells or Batteries

• Rechargeable
• Used for energy storage applications (e.g. solar backup, automotive)
• Used as rechargeable primary battery (electronics, electrical car)
• High power density
• High discharge rate
• Usually lower energy density
• Poorer charge retention