Diotec Semiconductor AG

http://www.diotec.com/

Feb 29, 2024

Diotec has developed integrated bypass diodes for Fraunhofer ISE's 'Baldachin' solar roof tile project

Fraunhofer ISE is the largest solar research institute in Europe, with around 1400 employees. On February 27, German Chancellor Olaf Scholz visited the ISE in Freiburg. A highlight of his visit was the demonstration of several solutions for photovoltaic systems integrated into building facades and roofs. Diotec is involved in one of these projects, called "Baldachin". Supported by the German Federal Ministry for Economic Affairs and Climate Action, the ISE initiated this project, where several industrial partners, among them Diotec Semiconductor, are developing an innovative solar roof element for next-generation building-integrated photovoltaics. It follows the shape and color of classic roof tiles without solar cells being visible, can easily replace existing tiles, and is cost-effective and reliable.

During the 50th IEEE Photovoltaic Specialists Conference in San Juan, Puerto Rico, the ISE together with Diotec published the article "Analysis of the thermal behavior and reliability of bare-die diodes embedded within PV modules as bypass devices".

Here is a short abstract of that article: Bypass devices within a photovoltaic (PV) module are becoming popular as an alternative to external boxes containing bypass diodes. However, technical challenges need to be addressed for reliable integration. This study focused on the role of diode geometry and material calculation in dissipating heat when partial shading occurs on a PV array, causing the diode to be in forward bias. Parameters for module-integrated bar die diodes were defined to ensure they remain below a maximum operating temperature of 95 °C. Various experimental approaches were explored, and a finite element method (FEM) model was created to predict maximum temperatures. The research found that chip size plays a significant role in efficient heat dissipation, and modifying the geometry of the diode connectors could effectively reduce device temperature without increasing the size of the semiconductor. Suggestions include using multiple small diodes in parallel, increasing the width of connectors, and adding flat heat sinks. Additionally, the study addressed the performance and reliability of these integrated bypass devices. For more information:

https://ieeexplore.ieee.org/document/10359705