Challenges in the design of concentrator photovoltaic (CPV) modules to achieve highest efficiencies

Abstract

Concentrator photovoltaics (CPV) is a special high efficiency system technology in the world of PV-technologies. The idea of CPV is to use optical light concentrators to increase the incident power on solar cells. The solar cell area is comparatively tiny, thus saving expensive semiconductor materials and allowing the use of more sophisticated and more costly multi-junction solar cells. The highest CPV module efficiency achieved is 38.9%. This CPV module uses four-junction III-Vbased solar cells. Moreover, mini-modules have already achieved an efficiency of 43.4%. The interaction between optics, cells, and layout of the module and tracker determines the overall field performance. Today, some utility scale CPV plants are installed. The CPV technology allows for many technical solutions for system designs and for optimizing performance while maintaining the economics. This paper will review the achievements and discuss the challenges for the CPV module technology and its components. We discuss the different components and the most important effects regarding the module design. Furthermore, we present the module designs that have shown the highest efficiencies.

Thin-film micro-concentrator solar cells

“…With respect to the concentration factor, the CPV system is classified as low-concentration photovoltaics (LCPV) for concentration factor <100X and as high-concentration photovoltaics (HCPV) for concentration factors between 300-1000X. While LCPV are typically linear systems based on crystalline silicon High operation temperatures decrease the power output or require the application of active cooling systems High local content for local manufacturing, installation, operation and maintenance [2,9,10] Too large variability of module architectures solar cells and single or dual axes tracking, HPCV are based on point-focus collectors, multi-junction solar cells and dual-axis tracking [2,9]. The concentration of sunlight and corresponding increase in the number of photons lead to a linear increase in the photocurrent proportional to the concentration factor (C).…”

“…A CPV system has two essential elements: the optical collector and the receiver [9,15]. The optical collector can be a mirror, lens or a combination of both [16] and the receiver consists of a solar cell with an optional secondary optical element (SOE), heat distributor and electrical contacts [9]. The collector and receiver are referred to as the concentrator module [9,15].…”

“…The optical collector can be a mirror, lens or a combination of both [16] and the receiver consists of a solar cell with an optional secondary optical element (SOE), heat distributor and electrical contacts [9]. The collector and receiver are referred to as the concentrator module [9,15]. A concentrator module is typically composed by • An array of solar cells designed for operation under concentrated light, appropriately interconnected electrically.…”

“…To decrease the costs of CPV, micro-scale concentrator photovoltaics (micro-CPV) (figure 1) have been proposed, where the solar cells are miniaturized to an area of less than 1 mm 2 [9,20]. By reducing the cell size to the sub-mm range, several benefits can be potentially achieved, such as materials savings, costs reduction, thermal management and enhanced efficiency [9,[20][21][22]. At the same time, the size dependence of efficiency of various types of solar cells can be different.…”

Relative misalignments estimation in on-tracker CPV modules through image processing

“…Concentrator Photovoltaic (CPV) is a technology that uses optical systems to focus sunlight into small highefficient solar cells [1]. These optical systems are usually compound of a lens as Primary Optic Element (POE) and another secondary optical element (SOE) coupled to the photovoltaic solar cell that can be reflective or refractive.…”