In this paper, we present a novel design and an optical simulation of a flat concentrator photovoltaic (CPV) system for electric vehicle application. The sunlight concentration component is comprised of a planar wave guide integrated dichroic mirror-coated cone prisms and a mirror-coated lens array. Sunlight reflects firstly at the mirror-coated lens array and then strikes the cone prism of the planar waveguide. The prisms are coated by the dichroic mirrors to divide the solar spectrum into two bands. The low-energy band is transmitted and reaches the GaInAsP/GaInAs dual-junction solar cells. The mid-energy band is reflected at the prism surface and coupled inside the waveguide. The exit port of the waveguide is attached with GaInP/GaAs dual-junction solar cells. The simulation results demonstrated a maximum electricity conversion efficiency of 32.88% at the high concentration ratio. The system thickness is 35 mm, which is as thin as the conventional flat photovoltaic panel and system allow for a lateral sun-tracking mechanism. This is suitable for installation on the vehicle's roof. The results showed that the presented flat CPV system is a new approach for a highly efficient application of solar energy to the electrical vehicle.