We searched for time-dependent solutions for the 5-dimensional system of a scalar field canonically coupled to gravity. For the case of time-independent scalar field, the time evolution of the scale factor is obtained for different values of the spatial curvature k=0,+1,-1. In the case of time-dependent scalar field, two classes of solutions are discussed and an extension of the superpotential formalism is proposed. This talk is based on JHEP 1404 (2014) 061.