Oxford PV, a perovskite photovoltaic specialist, and the Fraunhofer Institute for Solar Energy Research (Fraunhofer ISE) in Germany have jointly unveiled a new module prototype that combines Oxford PV's perovskite-silicon tandem cells with Fraunhofer's shingled matrix interconnect technology.

The new product will be officially showcased at the upcoming Intersolar Europe trade fair in Munich. The two organizations stated that both prototype modules achieve a full-area conversion efficiency of 25.6%.

Stefan Glunz, head of the photovoltaic division at Fraunhofer ISE, explained that in the new design, Oxford PV's tandem cells are cut into tile-like shapes, interconnected using conductive adhesive, and then encapsulated. The entire tandem module employs a double-glass structure with edge sealing to protect the moisture-sensitive perovskite cells.

"We are delighted to be able to integrate two high-tech solutions from Europe into this photovoltaic module," Glunz added.

Ed Crossland, Chief Technology Officer of Oxford PV, emphasized the complementarity of the two technologies. "Our tandem technology is highly compatible with shingled interconnect technology," he said. "Because perovskite-silicon solar cells have a lower current density, the cells can be cut into wider strips, thus improving production efficiency." He further explained that tandem cells have higher open-circuit voltage and conversion efficiency compared to traditional silicon cells; the current is shared by two layers of sub-cells, resulting in a lower overall operating current. Lower current density effectively reduces internal resistance losses within the module.

"Meanwhile, the matrix shingled interconnect uses conductive adhesive, a low-temperature process that eliminates the need for copper busbars throughout," Crossland added. Reducing the use of copper components lowers manufacturing costs and alleviates internal structural stress within the module.

The new design has been applied to two prototype modules: a 491W residential rooftop solar system with an area of ​​1.92㎡; and a 546W bifacial high-power solar panel with an area of ​​2.13㎡. Both modules achieved a conversion efficiency of 25.6% across their entire area.

Crosland stated that the structural design of this prototype module is fully compatible with mass production.

"Oxford PV's HyPERcell cell technology is compatible with multiple interconnect methods. Our current offerings have an efficiency of 25% and a lifespan of ten years, but with continuous improvements in cell and module manufacturing technologies, regardless of module design, we expect to achieve an efficiency of 27% and a lifespan of twenty years by 2027. This year we will launch a product with an efficiency of 26%," he said.

Tannel modules, combining perovskite and silicon-based photovoltaic technologies, are widely regarded as the next major leap forward in the solar technology roadmap. Adding a perovskite layer to silicon cells can significantly improve conversion efficiency, breaking through the theoretical limits of pure silicon cells. Oxford PV has been a leader in the development of tannel technology and is driving its commercialization through its pilot production facility in Brandenburg am Havel, Germany.

Fraunhofer's matrix tile technology uses conductive adhesives to connect solar cell strips in an overlapping, staggered manner similar to roof tiles. This achieves complete coverage of the module surface and has high tolerance to partial shading. Fraunhofer stated that this matrix arrangement allows current to bypass shaded areas, potentially doubling power generation compared to conventionally connected photovoltaic modules, depending on the degree of shading.

These two new photovoltaic modules are the result of the "HoTSun" research project funded by the German Federal Ministry for Economic Affairs and Energy. They will be exhibited in Munich soon.