Replacing the metal car roof with conventional solar modules results in the increase of total car weight and change of center of mass, which is not preferable for car designing. Therefore, weight reduction is required for solar modules to be equipped on vehicles. Exchanging glass to plastic for the cover plate of solar module is one of the major approaches to reduce weight; however, load bearing property, impact resistance, thermal deformation, and weatherability become new challenges. In this paper a new solar module structure that weighs as light as conventional steel car roofs, resolving these challenges is proposed. Using FEM (finite element method) models, the thicknesses and materials of laminated constitutions were determined which satisfy the target area density, impact resistance based on JIS R 3212 standard, whose energy is similar to IEC 61215 hail test, and which no significant thermal deformation at -30 degrees Celsius is observed. 600 mm by 1000 mm in size and approximately of 2800 mm to 11000 mm in curvature car-roof-like test pieces were made to check the characteristics of proposed laminated constitutions.