Hi @astonseb5 ,
Here’s the maintenance and service guide for the laptop, taken from this webpage.
Go to p.41 to view the necessary pre-requisite steps and then the procedure to remove/replace the fans.
As @aactech stated, always disconnect the battery as soon as possible when working inside a laptop and reconnect it as late as possible during re-assembly to help minimize any potential electrical problems when working in a laptop. You don’t have to remove the battery, merely disconnect it from the motherboard (see p.37)
There is always power present on the motherboard even when the laptop is switched off. The Power On/Off switch is not a power isolating switch. It merely signals the intentions of the user to the BIOS/OS as to what is wanted. Think of the laptop as being in an extremely low power state when off and not totally isolated from the power supply i.e. battery.