Towards crack free fabrication of interconnect shingled solar modules through wire length and wire-end geometry control

Reduction or elimination of cell-to-cell distance in a solar panel is a straightforward way to enhance solar module efficiency. Overlapping interconnection by wire shingling increases the active area in solar modules and allows to apply mainstream stringer technology, which reduces the cost of integration. However, since commonly used wires for interconnection have diameter of about 300 μm, mechanical load during lamination can result in crack formation. In this work, we demonstrate the potential for adapting process parameters and cell-wire configurations to eliminate crack formation in wire shingling technology. Our crack formation analysis identifies three types of crack formations that occur during the lamination of half-cut cells. These are cross cracks located close to the wire ends, v-shaped cracks at the overlap wire feedthrough in rear as well as in front cell. With short wire length and elliptical wire-end-shape, along with conventional lamination parameters and non-alternating cell arrangement we take the first successful step towards a feasible solution for the crack-free fabrication of shingled wire interconnect solar modules.