Power banks hold power in an interior Lithium Ion battery pack which enables it to charge the cell phone and tablets. To be more accurate, they could be described as an electric battery in beautiful casing which has an ability to regulate the supply of electric power. That’s the way I can express it in a non-technical manner. As an example, we can compare and contrast the power bank with a true financial institution where we deposit cash, after which take away the cash when necessary. This is a ideal analogy. Now that the battery total capacity of the gadgets we're using these days went way too low what we have been wanting it to with a multitude of tasks getting performed, there exists a need for an auxiliary power source and that is exactly where those power banks get into action.