How a battery works
Batteries store electricity in the form of chemical energy to use when they are connected to a device.
Batteries contain a positive cathode and a negative anode. These electrode terminals are made up of different materials depending on the battery type. When a device is connected to the battery, a chemical reaction occurs that generates positively charged ions and negatively charged electrons. The ions flow through electrolyte to the cathode; whereas the electrons (that cannot penetrate the electrolyte) travel around the outer circuit powering a device en route to the cathode. Disposable batteries die when the anode or cathode runs out of the chemical needed to catalyse the reaction.
When a device is recharged, electric energy from the charger (such as a phone charger plugged into a wall) is applied to the chemical system to reverse the process and restore the battery’s charge. Rechargeable batteries are thought to degrade because of the irregular movement of ions in the electrolyte.
Types of rechargeable batteries
The lifetime, cost, energy storage and re-usability of the battery are determined by the material used. This also dictates whether the battery is best used for devices that do not consume much energy or in those that do.
Ability to supply electric energy
How well high-drain devices are powered
The number of times the battery can be recharged in its lifetime
Composition and ease of recycling
Cost to consumer
Batteries and the smart grid
Sources of renewable energy such as wind and the Sun provide only intermittent power. Storing excess energy on sunny or windy days is of paramount importance. Several types of battery are being explored for their use as grid storage.
Source: B. Berger. (Fraunhofer ISE, 2014)
Batteries contain materials that could eventually run out. Countries that are rich in these resources could one day hold the same sway as today’s oil-rich countries. Lithium is one of the main concerns — demand for the metal has almost doubled in the past five years, with most of the world’s supply coming from Latin America.
The rechargeable-battery market of the future looks set to be dominated by lithium-ion batteries.