Batteries - Electrical energy storage

• Although there are many types of devices consisting of one or more electrochemical cells, we tend to refer to them all as batteries

  
• There are 2 main types of battery: primary or 'single-use', which we use and discard; and secondary 'rechargeable'. Both are extremely useful when we need electrical power in locations where mains electricity would be difficult or even impossible to access, such as moving cars

  
• Examples of primary types of include alkaline batteries, such as those used in clocks, and zinc-carbon, which although cheaper than alkaline batteries do not last as long or store as much electrical energy in the same space
• Typically, zinc-carbon batteries produce about 1.5 volts per cell
• Rechargeable batteries are more expensive to purchase than alkaline batteries, but are cheaper to use as they can be recharged many times
• There is a limit to how many times rechargeable batteries can be recharged. Nickel cadmium rechargeable batteries last longer if they're completely discharged before recharging. Lithium ion ones are more adaptable
• Rechargeable batteries typically have a cell voltage of 1.2 volts, so in a 12-volt device you would need 10 rechargeable batteries but only 8 single-use batteries
• For all batteries there are issues related to safe disposal, as they contain harmful chemicals and metals that must not be allowed to contaminate groundwater supplies
• Batteries come in a variety of shapes and sizes, with large lead-acid batteries for cars, trucks and even submaries at one end of the scale; and miniature batteries such as those used in hearing aids at the other