C.4 The “Flower Cell”

The ABC set and figurative cell fulfill both the demands and wishes. The ABC set has geometric lines, while the figurative cell has curved lines and is less familiar. Curved lines are difficult to screen print, and it is possible that these lines are incompletely filled with metal paste. To demonstrate that this contact pattern is producible, the figurative cell is chosen for detailing. This figurative cell has an abstract flower-shaped contact pattern and is named the flower cell.

A standard multicrystalline Si wafer was used as the foundation for the flower cell. The cell's dimensions were 15.6 × 15.6 cm, and the four final contact points have been located at the same location of the H cell for interconnections. The cells were blue colored and had the same finger pattern. The flower cell was inspired by the poppies of Andy Warhol's Flowers 1. The idea was to have a pattern that can be interpreted not only as a flower but also as a different figure. The detailing of the design was executed in several steps.

Firstly, pictures of flowers were gathered. A selection of flower shapes was collected in a collage (Figure C.4.1).

Figure C.4.1 Collage of flower shapes

Secondly, many sketches of possible flowers were developed. One flower was selected for the contact pattern, which is shown in Figure C.4.2. This cell can be used in four different configurations due to its asymmetric design. It is possible to place the flower cells in a pattern in a PV module. Next to that, the PV modules can form a pattern in the PV array.

Figure C.4.2 Definitive flower design

The flower cell has no sharp cornered lines but curved lines. The lines are designed such that they connect with each other, enabling collection of the generated electricity. The design of the fingers was kept the same because of the efficient screen printing. Four busbar lines, starting from the sides of the solar cell, are 2 mm wide; the lines of the flower are 1 mm wide. The height of the metal lines is 20 μm.