CPV module with triple-junction cells and double-bonded copper carriers


Canada's Crystal Green Energy and Congo-based startup Insolation Solaire aim to jointly commercialize concentrator photovoltaic (CPV) tech based on commercial triple junction CPV cells, combined with a double-bonded copper (DBC) single alumina ceramic carrier.

“The CP3 power module has been tested … at an operating temperature of over 150 C and promises to have a 37-year lifecycle with little degradation,” Crystal Green Energy CEO Gilles Leduc told pv magazine. “The power module and the optical components will be manufactured in North America and shipped to Congo facilities for assembly to reduce cost in shipping and to bring forward this technology.”

The company used CPV cells with an active area of 6.5 mm x 6.5 mm and an efficiency of about 40% at 100 suns. The cells were assembled into the DBC carriers via a commercial solder die-attach process.

“The power module assembly with the CPV cell solder process is a cost-effective solution to reduce the price of manufacturing,” Leduc explained. “Our design can incorporate the future developments of a higher efficient tandem cell structure.”

Each cell features an indium gallium phosphide (InGaP) subcell, a gallium arsenide (GaAs) middle cell incorporating indium gallium arsenide (InGaAs) quantum dots, and a bottom cell based on germanium (Ge). The cells were manufactured by Azastra, a Canadian supplier of optoelectronic devices, via the QDec measurement system. QDec complies with the IEC 6210 standard, which is used to shape quality control for mirror panels in solar concentrators such as parabolic troughs, heliostats and dishes.

The scientists used modular quad receivers equipped with anodes and cathode connectors to protect the individual CPV cells and to easily interconnect the modules into the panel assembly. The CPV system also integrates a Cassegrain beam expander for initial energy concentration and a Winston cone light concentrator for final energy concentration.

“Our design uses a light weight polymer with an efficiency of 98.5 % reflectivity molded quad primary and secondary mirror that reduces the cost of manufacturing,” Leduc explained. “The Winston cone also reduces the cost and assembly process.”

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They placed a heat exchanger beneath each carrier to prevent cell damage and reduce heat exchange to a hot water tank that can be used for domestic hot water and floor heating requirements in commercial applications.

“This off-axis configuration allows arranging the optics in a rotationally symmetric pattern, which in turn sets up the CPV cell assembly to be configured on a common substrate at the centre of this multisystem,” Leduc added.

The CPV modules can be assembled in a fully flexible power configuration and can be wired in full series.

“While the material costs such as DBC carriers will still increase approximately linearly with the number of cells, the assembly cost will be almost independent of the number of discrete components in a commercial die attach process,” Leduc explained.

The DBC carriers are made from gold plated copper on each side of an alumina ceramic less than 1mm thick based on an industrial process.

The two companies are now working on potential applications for heating, ventilation, and air conditioning (HVAC) systems in commercial buildings.

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