Cells and batteries

• Electrochemical cells use chemical reactions to produce electrical energy.
• A simple cell can be created by connecting two different metals with a wire, and placing it in contact with an electrolyte. There may also be a voltmeter to measure the voltage of the cell.
• Battery - two or more cells connected together in series for greater voltage
• Things that can affect voltage of a cell:

  1. The metals used for the electrodes (the greater difference in reactivity of the two metals, then the greater the voltage can be)
  2. Type and concentration of electrolyte used
  3. The conditions (e.g. temperature)
• Non-rechargeable cells and batteries:

  • The chemical reactions stop when one of the reactants has been used up
  • The reactions are irreversible, meaning it can't be recharged once one reactant is used up
  • Example: Alkaline batteries
  • Example of use in: smoke alarms and tv remotes
• Rechargeable cells and batteries:

  • The chemical reaction is reversible, when external current is supplied
  • Example of use in: laptops and phones