This thesis contains an experimental study on the virtual assembly of an electric vehicle battery box. Three strategies were tested for assembly to test the cycle time and the cobot utilization level. The strategies were a fully manual assembly in AR, a fully automated UR5 cobot assembly programmed in RoboDK, and an HRC assembly with Mixed reality using HoloLens in Unity. The joints were exported from RoboDK to Unity through a TCP server using Python. The results show that the manual assembly is the fastest. Considering other factors as cobot utilization and ergonomics, makes HRC a better-suited option for this project to remove harmful and repetitive moments for the human. The task allocation has two major components, where the box assembly is performed by the human and the fastening of the screws by the cobot. Many factors impacted the result, which leads to further research points to assess.