Depending on the make and model of the vehicle you wish to replace the battery in the tools may vary somewhat. You will need tools for removing the battery and also for preparing the cables for installing them on the new battery.
The first step is removing the battery cables and if you have an older car that has clamp style ends on the cables you will need a box end wrench, flat head screw driver, pliers and a pair of safety glasses. The safety glasses should be worn at all times when working with automotive batteries. A good pair of rubber lined mechanics gloves will also be needed when working with the battery to protect your hands from any battery acid that may be present. In Most cases the box end wrench will need to be a half inch SAE or 12mm. After using the wrench for loosening the clamp on the cable you will need the flat head screw driver to spread the connection open. Grasp the clamp on the cable with the pliers rotate it and pull at the same time until the clamp comes free from the battery post. If your car is newer it may have the cable ends that bolt directly to the side of the battery. These are usually small bolts that take an 8mm wrench. When removing the positive battery cable be careful not to touch the metal wrench to any other metal objects while it is on the bolt of the cable as this will cause sparks. Now you will need tools for removing the bracket that secures the battery to the car. If the bracket that secures the battery to the car is on the lower side of the battery you will need a deep well half inch socket, long extension and a ratchet for removing the bolt in the retaining bracket. Now you will be able to lift the battery out of place. Before putting the new battery in you will need a wire brush to clean any corrosion from the surface that the battery sits on. The cable ends will also need to be cleaned to ensure a good connection for the electrical current to pass through. Using the wire brush clean the cable ends and install the new battery. It is a great idea to have a fire extinguisher close by anytime you are working on the car especially the battery.