Higher Energy Yields by Avoiding Hot Spots

Current energy policy calls for large-scale installation of PV systems in residential and industrial areas. Due to the complexity of roofs and building elements (e.g., chimneys and trees), PV systems are likely to experience significant partial shading. Regular partial shading leads to significant energy losses and higher thermal loads, resulting in hot spots and polymer aging.

The current generation of hot spot-free modules has reached its limits with the advent of large solar cells with multiple busbars and wires instead of tabs. The SegmentPV project therefore aims to further develop a modified and updated patented hot-spot-free (HSF) module. This will take into account the industry-wide revolution in wafer sizes and partial cell designs, which has necessitated a design update and created a need for research into components for HSF modules.

The further development of the modified hot-spot-free (HSF) module is based on an analysis of various partial shading scenarios in which partial shading becomes part of normal operation. However, when implementing such specific module designs, the test and measurement regimes must be adapted, particularly in measurement and testing technology and in reliability assessment. In the Fraunhofer CSP subproject, SegmentPV is specifically looking at new cell technologies, sizes, formats (third or half cells), and different diode technologies (integrated active and passive bypass diodes) and how these components can be characterized and evaluated in an electrically reliable and yield-maximizing way. Measurement and testing methods are being developed to enable new cell and module concepts to be quickly evaluated and qualified. In the medium term, the test protocol will be standardized and established in the PV industry. The findings and the new product concept could lead to new application locations, particularly in urban areas, for new PV-integrated building solutions.

The target module will have a significantly lower hot spot risk under partial shading conditions and a significantly higher energy yield, resulting in lower energy costs. With this technology, a large part of the roof area can be covered with PV modules, which increases efficiency when roof space is limited. SegmentPV is expected to have a higher energy yield under partial shading conditions, lower system costs, lower energy costs, lower levelized costs, and very good durability on limited areas surrounded by obstacles that cause partial shading.