Photovoltaics International Papers

CIS thin-film module manufacturer Solar Frontier has signed a memorandum of understanding with Saudi Aramco and the Saudi Arabian National Industrial Cluster Development Program (NICDP) on the feasibility of establishing a thin-film module production plant in Saudi Arabia.

An efficient exchange of knowledge is essential to move the technology forward. In June 2016, the IW-CIGSTech workshop was organized for the seventh consecutive year in a row. This time, the event took place as a parallel event to the EU-PVSEC/Intersolar Europe in Munich. In the workshop, representatives from industry and academia gathered to discuss the latest developments in the fast-developing field of CIGS (Cu(In,Ga)(Se,S)2) based solar cells. As a result of last year’s workshop, a joint, community-wide effort resulted in the broadly acknowledged “White Paper for CIGS thin film solar cell technology”. In this article, we provide a brief impression of the progress and challenges reported in this year’s workshop.

The rebound in solar cell capital expenditures during 2015 and 2016 has resulted in strong capacity additions and upgrade spending that is set to redefine the technology landscape in 2017 and beyond. Within this however is a broad range of drivers, impacting the mix of n-type and p-type cells produced, in addition to the various strategies employed to increase cell efficiencies while reducing overall blended manufacturing costs. Coupled with the various module types being selected within the key global end markets, and the balance between effective capacity and market demand, 2017 is forecast to see a range of approaches adopted by cell producers, with technology differentiation becoming increasingly important across the entire industry.

In this quarterly report of global PV manufacturing capacity expansion announcements in the first half of 2016, key analysis is given on the continued high level of activity through the second quarter of the year. This report also includes a new bottom-up analysis of ‘effective’ capacity expansions since the beginning of 2014 to provide a better and more accurate assessment of the current manufacturing environment.

This paper examines the use of stencil printing instead of screen printing in order to achieve improved fine line print quality for greater efficiency. In addition, a comparison of polymer and metal squeegees on fine line print performance is analyzed, with varying line apertures studied to understand the impact on the efficiency of PERC solar cells.

The continual increase in cell efficiency of passivated emitter and rear cells (PERCs), as well as the optimization of the module processes, has led to significant advances in module power and efficiency. To achieve the highest module power output, one important aspect to consider is the optimization of the solar cell front metallization and the cell interconnection.

Most high-efficiency solar cells are fabricated from monocrystalline Czochralski (Cz) silicon (Si) wafers because of the high quality of the material. Despite the considerable heritage from microelectronics, the Cz-Si substrate quality can still limit cell performance.

Cell-to-module (CtM) loss is the loss in power when a number of cells are interconnected and laminated in the creation of a PV module. These losses can be differentiated into optical losses, leading to a lower photogenerated current, and resistive losses, leading to a decrease in fill factor. However, since the application of anti-reflection (AR) coatings and other optical ‘tricks’ can sometimes increase the Isc of the module with respect to the average cell Isc, the CtM loss in such cases needs to be expressed as a negative value, which gives rise to confusion. It is proposed to use the CtM change, where a negative value corresponds to a loss in current or power, and a positive value to a gain. In this paper, the CtM changes for back-contact modules utilizing a conductive foil are described and compared with other mature module technologies. A detailed analysis of the CtM change for a full-size metal-wrap-through (MWT) module is presented.

Higher power generation yield is the prime objective of any solar power plant developer. The quality and reliability of the modules used are therefore a key aspect, with customers placing stringent criteria on cell and module manufacturers with regard to product quality. Electroluminescence (EL) image monitoring, which gives a clear picture of defect distribution across a module, is an increasingly popular quality criterion.

With the PV industry continually pushing for ever-higher silicon solar cell efficiencies, the requirements on the electronic quality of the bulk material are becoming more stringent. Advanced characterization of silicon ingots after cutting into bricks allows early quality control and immediate feedback in crystal growth, thereby facilitating shorter R&D cycles, higher yield, lower cost and higher product quality in mass manufacturing.