Batteries

Introduction:

  • An electrical battery is one or more electrochemical cells connected together which convert chemical potential energy into electrical energy.
    • The smallest commercial cell supplies a voltage of 1.5V.
  • There are two types of batteries:
    • Primary batteries:
      • These are disposable batteries meant to be used and discarded.
    • Secondary batteries:
      • These are rechargeable batteries meant to be used and reused multiple times.
  • Batteries either convert chemical energy into electrical energy or store electrical charge directly.

Alkaline:

  • Properties:
    • Can provide a steady current and voltage for a long period of time.
    • Have a longer shelf-life than zinc chloride batteries.
  • Capacity:
    • Higher than zinc chloride batteries.
  • Uses:
    • Interchangeable with zinc chloride batteries.

Zinc Chloride:

  • Properties:
    • Cheaper than alkaline batteries and come in the same sizes.
    • They are non-rechargeable.
  • Capacity:
    • Much lower capacity than alkaline batteries.
  • Uses:
    • Mostly used for products that do not need a continual high output for a long period of time such as film cameras and game consoles.

Nickel Cadmium:

  • Properties:
    • More expensive than most other batteries however they are rechargeable.
  • Capacity:
    • Much lower capacity and voltage than both alkaline, zinc chloride and lithium batteries.
  • Uses:
    • Mostly used for products that generate electricity of their own such as in cars or electronic toys.

Lithium:

  • Properties:
    • Rather expensive but produces a constant voltage for a relatively long time.
  • Capacity:
    • A low capacity when compared to zinc chloride and alkaline batteries.
  • Uses:
    • Mostly used for devices that require a high constant voltage such as a digital camera, or anything that uses alkaline batteries.

Silver Oxide:

  • Properties:
    • Very expensive.
    • But can make very small batteries that are able to provide relatively high voltages for sustained periods of time.
      • For this reason they are used to make the smallest of batteries.
  • Capacity:
    • For similarly sized cells, they can provide a much greater capacity than alkaline batteries.
  • Uses:
    • Mostly used in products that are small or must have flexible casings such as watches, etc.

Lead-Acid Battery:

  • Properties:
    • Can supply high surge currents.
    • Inexpensive.
    • Relatively large power to weight ratio.
    • Low energy to weight ratio, low energy to volume ratio.
    • They were the first rechargeable batteries made.
  • Capacity:
    • I would imagine that they have a low capacity.
  • Uses:
    • Car batteries, etc.

Battery Sizes:

  • From small to large: Button Batteries, AAA, AA, C, D sized batteries.
  • PP3 batteries are 9V batteries.

Dangers:

  • Some batteries contain mercury or cadmium:
    • Mercury is a heavy metal and is thus toxic.
    • Cadmium is a carcinogen.
  • Batteries should not be dismantled or thrown into a fire after usage.
    • Because if a battery is opened it may cause hazardous materials to leak into the environment and can cause a variety of problems such as heavy metal poisoning or even lead to cancer.
    • Also throwing a battery into a fire is most unwise since batteries may explode if this is done.
  • Thus we must make sure that we give the batteries to recycling services so that materials such as lead, mercury and cadmium may be recycled or disposed of safely.

Key Terms:

  • Ampere-hour:
    • It is a measurement of electrical charge.
      • Charge is measured in coulombs.
      • It is derived from the formula:

Charge

    • A 1 ampere-hour, or amp-hour, battery can produce a stable current of 1 ampere for 1 hour.
  • Capacity:
    • It is the maximum charge contained in any power source and is measured in ampere-hours.
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