Fraunofer ISE, Heckert Solar present Made-in-Germany rooftop solar panel

Fraunhofer ISE and Heckert Solar have collaborated on the development of a high-efficiency PV module with M12 half cells and a 20.5% efficiency rating. Fraunhofer ISE handled conception, pre-development, and initial prototype production, while Heckert Solar established a new production line at its main facility in Chemnitz, Germany, for the 400 W module, targeting residential use.

“The jointly developed photovoltaic module is characterized by the use of M12 half cells with twelve busbars and a special arrangement of the solar cells through a so-called cross-string design,” said Christian Reichel, project manager at Fraunhofer ISE. “The resulting reduced mechanical stress on the solar cells and cell connectors reduces the risk of breakage of the solar cells.”

The PV module's design integrates findings from Fraunhofer ISE's life cycle analysis across different module types. To minimize the CO2 footprint, the research team developed optimized supply chains for the module.

“We have already been able to implement part of the production concept for the smallest possible CO2 footprint that was developed in the project,” said Ronny Köhler, head of quality assurance at Heckert Solar. “We only use green electricity to produce the modules, most of which is generated by our own photovoltaic systems on the factory premises. The waste heat from our offices and packaging materials are largely reused.”

The module has been in series production since the beginning of this year. Although the larger M12 cells significantly enhance solar module efficiency, standard European production lines cannot process them, according to Fraunhofer ISE.

German PV production equipment supplier Teamtechnik developed its stringer systems for this format as part of the project. The new flexible stringer for various cell formats and with the option for flat wire and round wire connection is now part of the Chemnitz production and is also used in the Module-TEC laboratory at Fraunhofer ISE.

Heckert Solar expanded its annual module production to 400 MW this year by constructing an additional factory in Langenwetzendorf, Germany. In August 2022, the company announced a €2 billion ($2.2 billion) investment in PV production in Germany with Interfloat and Wattkraft.