In this thesis, an experimental cooling system design process was described, for an apparatus to be used for testing of battery cell cooling via two phase cooling medium in a closed compartment. The system is composed of an imitation of a battery module, which is hermetically sealed and which contains heaters shaped like battery cells and the coolant. The condenser is placed atop of the module, and it is water or water-glycol cooled. Condenser is a part of the cooling loop which is cooled by a chiller. The purpose of this system is exploring the possibilities of applying the two phase cooling technology to an automotive battery pack. The goal of the application of this technology is homogenizing the temperatures across the battery cells in the battery pack, increasing the cooling efficiency, and lowering the mass of the battery pack. The thesis encompasses researching the existing technical solutions and patents, researching the effect and performance of the application of this sort of technology in a battery pack, design and standard part choice, 3D modelling using a top-down methodology and technical documentation, and summarizing the testing procedure of the test which is to be performed on the system.