SPLTRAK Abstract Submission
Novel Interconnection Method for Micro-CPV: 132 Solar Cell Prototype
Norman Jost1, Steve Askins1, Richard Dixon2, Mathieu Ackermann3, Cesar Dominguez1, Ignacio Anton1
1Insituto de Energía Solar Universidad Politécnica de Madrid, Madrid, Spain
/2Dycotec Materials Ltd, Swindon, United Kingdom
/3Insolight SA, Lausanne, Switzerland

Micro-concentrator photovoltaics (micro-CPV) consists of the reduction in size of the components of the conventional concentrator photovoltaic (CPV) technology, attaining equally high efficiencies and reducing material costs and manufacturing costs. In this publication we focus on the implementation of high throughput manufacturing methods for the interconnection of the solar cells. The goal is to enable large area interconnection of thousands of micro-solar cells with a low cost of 3€/m2, considering low cost silver inks and screen printing as used for the research in this publication. The method used is a result of crosslinkage with another industry, the assembly and interconnection of light emitting diodes (LED) for illumination or TV screens. The method consists in the following steps:
1.   Screen printing of the interconnection tracks on the glass board and curing at high temperatures of over 100°C.
2.   Pick-and-place of the solar cells and reflow soldering for the electrical contact and adhesion.
3.   Dielectric syringe printing around the solar cells for electrical insulation of the solar cell lateral and ultraviolet light curing of the dielectric. This step would be disposable if dies are electrically insulated.
4.   Screen printing of the final interconnection layer with epoxy silver ink and temperature curing.
Step 2 can be reemplaced by other paralell assembly methods such as fluid self assembly or transfer pritning of dies. Step 3 can be avoided by the use of perimiter insulted solar cells which will be available in the future. The current prototype is a 145x190mm2 board with a successful interconnection of 12 rows containing each 11 x 1mm2 inverted metamorphic multi-junction solar cells (132 cells in total). The fill factor (FF) of the full board is 76% at 214 suns. The tecnology is further developed for the purpose of using even smaller solar cells and interconnecting on a larger area.