Electrodes

• Electrodes come in two types: the cathode and the anode. The cathode collects positive ions from the chemical reaction in the battery, while the anode collects negative ions. As a chemical reaction called reduction-oxidation is triggered in the battery, the positive ions are added to the anode and negative ions to the electrode by turning them into different oxides. This causes current to flow through the battery, powering the device. When the electrodes are fully oxidized, the battery dies.
  
  

Electrolyte

• The electrolyte is what enables the two electrodes to interact. It is sometimes called "battery acid" as acids are sometimes used as electrolytes. However, not all batteries will contain acid strong enough to cause injuries. The concentration of the acid will be very different from battery to battery. The electrolyte allows the electrodes to be in electrical contact with each other without touching and also helps to trigger the reduction-oxidation reaction.
  
  

Separator

• The separator has a modest, but very important, job. It keeps the electrodes from touching each other. If the electrodes touched, it would immediately render the battery useless and possibly trigger an explosion, depending on the type of battery and how much of the original electrode was left. The separator keeps the oxidation reaction going at a standard pace and allows the battery to last a longer time. Separators are generally made from non-conductive, absorbent material, such as cloth.
  
  

Collector

• The collector is what delivers the current to the device. As current flows through the collector, it absorbs it and passes it on to the device. This is why batteries left in a device will continually power down even if turned off. Once the collector completes the circuit, it will continue to pass on the current, even if the device is turned off. Break the circuit, however, and the collector will not keep the electrons and will not trigger the reaction.
  
  

Container

• The container of the battery is the most important aspect of the battery in terms of safety. The container must be designed to withstand the chemical reaction inside of it, which can be extremely energetic, and also withstand any abuse delivered to it on the outside. The container must also resist corrosion over time, which is a risk with the results of any chemical reaction. Most battery accidents are caused by failure of the container.