Imec and Besi show reliability of Ni-Cu-Ag plated solar cells

03 Jan 2017

Demonstration achieved in five full size modules plated with alloy – confirming value of metallization.

imec, the Leuven, Belgium-based research and innovation hub, and BE Semiconductor Industries (“Besi”), a manufacturer of assembly equipment for the semiconductor industry, have demonstrated long-term reliability in five full-size (60) solar cell modules plated with nickel/copper/silver (Ni/Cu/Ag). The scientists behind this development say that this result confirms the industrial value of this particular metallization technology.

The modules consist of 60 front side, laser-ablated and Ni-Cu-Ag plated p-type Cz-Si cells. The plating was performed using Meco’s Direct Plating Line, an industrial plating tool, followed by annealing in an inline belt furnace. Cells were interconnected using standard soldering and lamination processes.

Extensive testing

The developers reported that two of the five modules were subjected to 600 thermal cycles (between -40°C and 85°C) and they passed this IEC61215 specification three times with overall power losses of only 1.5% and 1.8%.

One of the modules was subjected to a 1000-hour damp-heat test (at 85°C and 85% RH) with no power loss (in fact, a 0.1% gain), and two of the five modules were submitted to a serial testing of 15 kWh UV-conditioning followed by 50 cycles of temperature cycling followed by 10 cycles humidity-freeze-test, after which they showed overall power losses of only 0.5% and 3.0%.

imec and Besi say these test results demonstrate the long-term reliability potential of their copper-plated cells and modules, as they have now outperformed the industrial standard for reliability, which requires less than 5.0 percent loss relative to initial power.

“We are very pleased with these results,” said Richard Russell, principal engineer at imec. “It demonstrates our industry-leading knowledge on how to manufacture reliable Ni/Cu/Ag-plated solar cells and modules with a low cost industrial manufacturing process.”

Martijn Zwegers, product manager, solar at Besi, added, “After the excellent result of the 600 thermal cycle tests earlier this year on one module, we are delighted to confirm that these results can be repeated on a larger set of five modules. It also indicates that modules with copper-plated cells can achieve industry-standard reliability, paving the way for Ni/Cu/Ag plated cells as a viable, low-cost alternative to front side screen printing of silver pastes.”