Analysis of the bending and torsion strength of TOPCon solar cells cut by thermal laser separation technology: Advantages for vehicle-integrated photovoltaics

The rapid deployment of photovoltaic (PV) systems in diverse applications is crucial for facilitating the transition to a carbon-neutral society. Vehicle-integrated PV (VIPV) technology shows promise in reducing CO₂ emissions within the transportation sector. However, several challenges must be addressed in the design and fabrication of VIPV modules, including compatibility with 3D curved vehicle bodies and durability under various mechanical loads encountered in operating environments—such as torsion of the targeted installation bodies—which differ from the requirements of conventional static PV modules. This study quantitatively analyzes the mechanical strength (bending and torsion) of tunnel oxide passivated contact (TOPCon) crystalline silicon solar cells cut using thermal laser separation (TLS) technology through comparison with identical solar cells cut using laser scribing and cleaving (LSC) technology. Ball-on-ring and four-line bend tests are conducted on state-of-the-art TOPCon half-cells, and their stress characteristics under spherical surface deformation are evaluated through finite element method simulations, revealing the optimal cell size (182 mm × 45.5 mm, aspect ratio = 4) for integration into a spherical surface with curvature radius of 1 m. In addition, the torsional strength of the TOPCon half-cells integrated into a polymer-based submodule is experimentally assessed, and the mechanism of crack initiation is identified. The results demonstrate the superior durability of TLS-cut cells against bending and torsion loads compared with LSC-cut cells, indicating their advantages for VIPV applications.