Energy Density Of Lithium-Ion Batteries

The 18650 format factor provides a useful starting point as it is very common in applications from laptop batteries and flashlights to wireless equipment and electric vehicles. 

The first four digits indicate the physical dimensions, while the fifth digits indicate that the cell is cylindrical. The standard 18650 battery is 18 mm long and about 65 mm long. You can also check for the  18650 lithium ion battery through the web.

Gabbar 18650 Rechargeable Li-ion battery 2 pcs 3.7V Battery - Gabbar : Flipkart.com

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The performance of lithium-ion batteries can be changed by changing the choice of materials used for the electrolyte, cathode, and anode. The cathode is metal oxide while the anode is made of porous carbon material.

Manufacturers replace ingredients and/or use additives to degrade cell performance. For example, some batteries are designed to maximize energy capacity and provide long hours of operation, measured in hours. 

They are often referred to as "energy cells". Power cells, on the other hand, have a moderate capacity, but can carry large currents.

For example, a 18650 cell with a nominal output of 2000 mAh can deliver a continuous load current of 20 A (30 A with Li-phosphate). Superior performance is achieved in part by reducing internal resistance and optimizing the surface area of the active cell material.

Lithium-ion battery cell voltage

The voltage generated by each lithium-ion cell is about 3.6V, which is higher than that of standard nickel-cadmium, metal-nickel hydrides, and even standard alkaline cells around 1.5V and lead-acid around 2 V per cell.