Electrical and shading power losses of decorative PV front contact patterns
✍ Scribed by Michael Radike; Johann Summhammer
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 178 KB
- Volume
- 7
- Category
- Article
- ISSN
- 1062-7995
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✦ Synopsis
Visual appeal is an important criterion for the acceptance of photovoltaic modules in facades and roofs of buildings, or in village electri®cation. With crystalline silicon solar cells, the busbars are often seen as disturbing. Therefore, we tried to convert the busbars into an attractive feature by incorporating artistic design. Busbars should have an eye-catching eect. But increased shading or non-optimal ®nger layout should have no signi®cant eect on eciency. In the present work we calculated the dierent losses of newly designed front contact patterns. The design concept was to have a few basic front metallisation grids at the cell level, which would permit a large number of dierent appearances at the module level. Fifteen new metallisation patterns were compared to the standard metallisation grid regarding the dierences in shading and in the electrical losses. Nine of the new patterns are variations of the well known twobusbars scheme. Two patterns have connection points in the middle of each side of the square cell and a completely asymmetric inner layout. This leads to a large number of possibilities of irregular looking modules, not unlike stone or broken glass. Another one is designed to create the appearance of a hexagon web at the module level. Three other cells are designed to create an `art-deco' pattern when combined to a module. By taking into account resistive losses in the emitter layer, in the ®ngers and in the busbars, and contact losses between ®ngers and emitter layer, as well as shading losses, we ®nd that the eciency of a cell with the worst pattern would be only 0 . 71% absolute below that of a cell with standard pattern and an eciency of 13 . 80% at 1-sun conditions (1000 W/m 2 ). Artistic design of the busbar layout of crystalline silicon solar cells can therefore be achieved without an undue decrease of conversion eciency.