The ordinary crystalline solar panels used in the vast majority of solar installations in the Netherlands consist of an area of about one by one and a half metres, on which all individual solar cells of about 16 by 16 cm are stuck. Thin power wires connect all those cells together so that the power generated per cell can flow out of the panel and be used in the home.

Twice as many cells

Manufacturers are constantly trying to come up with new ways to optimise that current, and Q-cells uses something special for that purpose, namely half-cut cells, or half-cells.

In the new Q.PEAK DUO G5 solar modules, the solar cells are literally cut in half and thus stuck onto the panel as half cells. As a result, the panels are covered with twice as many small cells as normal: 120 cells instead of 60. The idea behind this is that the current within a cell always experiences some resistance, and that resistance depends on the distance the current has to travel through the cell. By dividing the cell by half, the distance is also divided by half, and thus the loss due to resistance is also less.

Upper and lower halves separately

Upon entering the panel, the current is split into two parts: one part goes through the cells in the upper half, and the other goes through the lower half. At the end, these currents converge again. These two separate currents are only half the size of what normally flows through the cells: again, this should result in less loss due to resistance. The half-cell technology yields a power gain of 3%.

and advantage of splitting the panel into an upper and a lower half with separate currents, is that shadow on one of these halves does not affect the other half (provided you have an inverter that can deal with this, such as the SMA inverters with the OptiTrac Global Peak, or ShadeFix, feature). With an ordinary panel, the by-pass diodes solar panel into 3 or more relatively independent longitudinal sections. However, if shade falls across the entire underside of the panel, the entire panel suffers. In the case of these Q.PEAK DUO G5 panels, the top half could still rotate in full, even though the panel (and thus the entire string it is part of) produces only half as much power: So only useful in very specific cases!