Lithium technology offers the highest energy density of all rechargeable cell technologies available on the market. Lithium cells are almost 4 times lighter than lead-acid cells. They are characterised by long life, far exceeding the possibilities of nickel and lead-based technologies. It should also be noted that Li-ion cells are much more environment-friendly than nickel-based and lead-acid cells. Currently, owing to all their advantages, Lithium-ion cells are used in all kinds of equipment powered by electricity: from e-mobility through devices for PV systems to large energy stores