In-cell bypass diodes for high-efficiency and shading-tolerant back contact silicon photovoltaic modules.

Abstract

Partial shading is a common condition in the outdoor deployment of photovoltaic modules, potentially causing significant power loss and severe thermal damage. Limitations of existing solutions in balancing effect and cost necessitate a thorough solution, which involves a fundamental redesign at the solar cell level. Here we propose a cell architecture featuring integrated reverse conductivity to address this challenge. We derive the design principles by drawing inspiration from bypass diodes, and manage to introduce spatially uniform reverse conduction channels to the cell. These engineered in-cell channels exhibit bias-dependent switching behavior that enables reverse conductivity of the cell without compromising power conversion efficiency. The underlying mechanisms and modulation strategies of the cell are elucidated. Prepared photovoltaic modules composed of the proposed cells demonstrate clear advantages in thermal management and power output stability under partial shading conditions. The design principles and conduction channel strategies in this work also provide insight for other passivating-contact solar cells. The in-cell design approach offers merits in reliability, cost, and integration, and holds promise for next-generation photovoltaic technologies.