They are shredded to small pieces. Magnet separates all ferromagnetic parts, like steel casings. There can also be other separation methods such as flotation. Various non-ferromagnetic materials such as zinc and manganese can be dissolved in sulfuric acid. In order to speed things up, leaching is done at an elevated temperature.

In the next stage, Mn and Zn are precipitated as hydroxides using submerging like sodium hydroxide for example. There are other options too. You could also melt the batteries and separate the metals that way. If you use pyrometallurgy instead of hydrometallurgy, you’ll be using a lot more energy.