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The success and expansion of the Photovoltaic's electricity production is largely based on the capacity to reduce solar panels cost ($/Wp), increase module energy yield and reliability. The booming of the PV industry in the last ten years was mainly based in the success to continually reduce the solar panel production costs: improve processes, reduce raw materials usage and economies of scale. However, in the same period, the cell and module technologies used didn’t change much. Reduce further the solar cell panel cost ($/Wp) become harder and harder with conventional crystalline silicon PV technology. Hopefully, alternative cells and module technologies are now ready for large volume production to bring down price of the photovoltaic energy. The combination of two revolutionary cell and module concepts: heterojunction solar cells and Smart Wire Connection Technology module technology are leading technologies for the next generation of PV modules. These two concepts combine high module power (>300 Wp based on 60 cells module) and a cell production cost as low as 13 c$/Wp. This paper presents some of the latest cell metallization improvements of heterojunction solar cells dedicated to SWCT technology. On the front side, the use of interrupted front fingers instead of continuous fingers was explored. This new pattern reduces front finger shading and increases module power. In the cell back side, a new pattern with fingers screen printed at 45 degrees to the cell edge was introduced. This special orientation of fingers allows to economize ribbons used to interconnect strings in modules.

After a flat PV market for several years, it recently started to grow strongly again. More and more solar cell manufacturers focus on high efficiency solar cells with low costs. The hydrogenated amorphous (a-Si:H) /crystalline silicon (c-Si) hetero-junction (SHJ) technology provides a well suited application to achieve efficiencies above 23% with process temperatures below 200°C. The whole process flow (Fig. 1) is simple and with less process steps compared to the standard solar cell process[1]. The low temperature coefficient (−0.2 %/K) of the SHJ solar cells provides additional benefit in output power for PV systems. The recent world record SHJ cell with an efficiency of 25.6% on a 4 inch n-type solar cell, reached by Panasonic Corporation has shown even more potential for future mass production.

Meyer Burger develops a high-efficiency line concept with a silicon heterojunction (HJT) cell based module. This line produces 2400 6-inch busbarless cells per hour and includes cells and modules characterization. The underlying high-efficiency bifacial module technology relies on the Smart Wire Connection Technology (SWCT) and on a Glass-Glass (GG) module design. The SWCT and GG concepts have been developed to benefit from the natural symmetry and bifaciality of the HJT cell. Our preliminary results demonstrate that our HJT cells can be incorporated into a record 60 156mm*156 mm cell module of 316 W. This paper reports on modules made on our pilot line in Switzerland and in Germany and presents outdoor measurement performances comparing our HJT bifacial modules with other technologies such as CdTe, CIGS and c-Si. Those results demonstrate a clear path towards modules with an equivalent power of 350 W for a 60-cell module.

SmartWire Connection Technology (SWCT) developed by Meyer Burger uses multiple thin copper wires with alloy coating to interconnect solar cells. These thin copper wires separate a 156 mm solar cell into unit cells, which typically have ∼4 mm finger length instead of 26 mm as in the case of three busbar solar cells, thereby substantially reduce the requirement of finger line conductivity. Such a low requirement of finger conductivity has enabled diverse metallization schemes to be successfully applied to many cell designs to reduce silver consumption and to be integrated into modules easily. In this paper, we present the module integration results of silicon heterojunction solar cells using various metallization schemes developed within Meyer Burger group, including fine line silver screen printing down to 80 mg per 6 inch bifacial cell, inkjet direct silver printing down to 10 mg per 6 inch monofacial cell, inkjet masking and nickel/copper plating to finger thickness as low as 1 µm on 6 inch monofacial cell. We demonstrate the high durability of these modules with extensive thermal cycling tests.