Kaneka Corp announced how it achieved a cell conversion efficiency of 24.2% with its 5 x 5-inch (171.28cm2) crystalline silicon (Si) photovoltaic (PV) cell at EU PVSEC, an international conference that took place from Sept 30 to Oct 4, 2013.
At the conference, Kaneka also explained how it achieved a conversion efficiency of 23.6% and output of 5.64W with a 6 x 6-inch (239.37cm2) crystalline Si PV cell. And the company said that it is possible to realize a 6W 6 x 6-inch cell with a conversion efficiency of 25% by further improving materials and process technologies.
This time, Kaneka announced a monocrystalline Si PV cell using hetero junction and copper (Cu) wire. Hetero junction allows to place amorphous Si on crystalline Si, preventing carrier recombination at the joint. Also, by replacing wires made of silver (Ag) paste on the surface of a cell with copper-plated wires, it becomes possible to reduce interconnection resistance and material cost.
Kaneka disclosed the results of a reliability test for a module consisting of prototyped cells. Even after being tested at a temperature of 85°C and moisture of 85% for 3,000 hours or a temperature cycling test in which the temperature repeatedly drops to -45° and rises to +85° 600 times, the properties of the module did not change much. The conversion efficiencies were measured by Germany-based Fraunhofer ISE.