Are there any fuses that i can use to protect a 18650 battery pack. I have a 2s8p which is rated at 12.6v 21.6A. one battery is rated at 4.2v at 2700mAh.
Sure, you can fuse the output of the pack. You'll want to dig into the datasheets for those batteries and see if that's peak current (likely) or continuous safe current. Design your fuse to trip accordingly.
If you need something resettable (can be reused upon removal of the fault condition), check out PTCs. PTC = Positive Temperature Coefficient. Essentially, it's a resistor that is low resistance under normal operating conditions, but as it heats up due to an over-current situation, resistance increases (hence positive temp coefficient) and cuts off the supply. Upon cooling it will become low-resistance again.
Here's the DigiKey link to PTCs so you can start selecting one for your specs.