A standard battery consists of two electrodes (an anode and a cathode) and an electrolyte. The anode is negatively charged and the cathode is positively charged. The electrolyte varies according to the type of battery and has the function of circulating ions from one electrode to another. The ions allow the circulation of electrons inside the electrolyte, the latter being responsible for the generation of an electric current.
That said, when an electrical voltage is applied across the electrodes, an electrical current builds up and creates chemical reactions on the surface of the electrodes and in the electrolyte. During the discharge, the positive plates consume electrons (reduction reaction) and the negative plates release electrons (oxidation reaction). In contrast, during charging, the positive plates release electrons (oxidation reaction) and the negative plates consume electrons (reduction reaction). The product of the electrons exchanges is the generation of an electric current.
The most well-known types of batteries are lead-acid, AGM, gel and lithium batteries.
Lead-Acid batteries are the most common type of battery in the world of storage due to their technological maturity and low price. However, they need to be stored in a ventilated place and to be maintained monthly.
AGM batteries are lead-acid batteries whose interior is solid rather than liquid. This characteristic means that they require no maintenance and can store more energy than a conventional battery. Compared to gel batteries, they excel in high discharge intensities.
GEL batteries are similar to AGM batteries, the only difference being that silica has been added to the electrolyte so that it is in a viscous gel form rather than a liquid form. Compared to AGM batteries, they excel in slow discharge intensities and higher ambient temperatures.
Lithium batteries mark the beginning of a new era of energy. They tolerate complete discharges, they have the best energy densities, they are bluetooth and can even be self-heating. They are also the most resistant to high charge and discharge intensities. Although they are more expensive than the other types of batteries described above, they are the most durable choice.