Energy density plays a big role in Lithium-ion’s dominance in the battery market. Energy density is the amount of energy that can be packed per unit weight.

The Lithium-ion chemistry is volatile in nature if the cell is operated outside the recommended temperature, voltage and current ranges. To avoid such a situation, a Battery Management System is needed to observe the cell’s behaviour and stop it from going outside its limits.

Polarization effect causes a difference between Closed Circuit Voltage (CCV) and Open Circuit Voltage (OCV). When discharging, the CCV is lower than OCV and it the CCV takes time to converge to the true OCV (around 20 – 30 minutes) after the load is disconnected. A similar effect is seen when charging the cell where the CCV is greater than the OCV. This effect can be modelled by the internal resistance of the cell.

Memory effect was first observed in Ni-Cd and early age Ni-mH type cells, and since the invention of Lithium-ion in the 1980’s it has been marketed to not show the memory effect. While this is mostly true, some chemistries of Lithium-ion (like LFP and LTO) show an effect which is similar to the memory effect. Read more about it here.

Lithium ion batteries have high energy density, which means they can pack a lot of energy in a small amount of weight. They can also provide high instantaneous and continuous power output. With their steadily declining cost, they are becoming increasingly popular in automotive, solar, aerospace, and telecom applications.

There are 3 main parts to a Lithium ion cell. The anode, cathode and the seperator. The main constituents of the anode and cathode are the substrate, current collector and the active material. The substrate provides the structural strength needed for the electrode, the current collector facilitates the flow of electrons in and out of the electrode and the active material is what hosts the lithium ions and electrons in its structure. The seperator has a special property that it allows the flow of ions through it but not electrons. Thus, the electrons are forced to travel out of the cell which is what is used to drive a load.