Structural design and demonstration of three-dimensional curved photovoltaic modules using crystalline silicon solar cells

The rapid deployment of photovoltaic (PV) devices through diversified applications is essential for advancing toward a zero-carbon society. The development of three-dimensional (3D) curved PV modules is crucial for new PV applications, such as vehicle-integrated PV systems. However, commonly used solar cell materials, particularly crystalline Si (c-Si), are inherently brittle and fragile. These characteristics present significant challenges for their integration onto 3D curved surfaces, thereby restricting the expansion of the PV coverage area. This study proposes a structural design methodology for 3D curved PV modules, incorporating flexural tests of solar cells, mechanical stress analysis across various cell sizes and radii of curvature (R), and evaluation of the risk of cell breakage when shaped to the targeted 3D curved geometries. Practical-scale 3D curved PV modules, featuring a 3-inch c-Si cell array with isotropic R values of 1 m or 1.5 m, have been successfully produced and characterized using electroluminescence and current-voltage characteristic measurements. The solar cell placement design has been implemented on an actual automobile body, identifying suitable surfaces for c-Si cell integration without the risk of breakage. The results demonstrate that reducing the cell size can enhance the total installed cell area on the automobile's body.