Lithium battery packs come in all shapes and sizes but share mostly the same components. If you were to open up a battery pack you would find several components. It is recommended not to open the battery pack, as it can lead to shortages and/or fires. The first component to look at is the actual battery cell. These battery cells almost resemble AA batteries in most cases. Some can be shaped similar to a 9-volt battery. These are the life blood of the battery. The pack also has several components to monitor the battery.