Batteries and accumulators are electrochemical power sources. This means that electricity is generated in them as a result of chemical reactions. Each accumulator or battery consists of one or several cells. This creates the necessary supply voltage. The batteries contain secondary or rechargeable cells. In the case of batteries, we are dealing with primary cells, i.e. non-rechargeable cells. Batteries are divided into: zinc-carbon, zinc-air, lithium, alkaline, mercury, silver oxide. The batteries include: lead-acid, lithium-ion, nickel-hydride, nickel-cadmium.