Front grid optimization of Cu(In,Ga)Se2 solar cells using hybrid modeling approach

Abstract

This paper describes the hybrid approach to modeling and simulation of thin film solar cells with a metal front grid. A 3D model with high aspect ratio of device thickness (100 s of nm) and its length and width (mm and cm range) was divided into two coupled models with different number of spatial dimensions (a 1D and a 3D model) on different length scales. The first one is modeling of the material level of solar cell which is then coupled with the second model taking into account the photovoltaic (PV) cell/module geometry. It calculates the photo-current flow through the transparent electrode dictated by the shape of metal front grid. This approach enables the separation of the technology-dependent material simulation from the front grid design simulation. In this paper, the use of the developed model to simulate solar cells based on Cu(In,Ga)Se 2 technology is described. The metallization in the form of parallel fingers was investigated and optimized for the described case study. Finally, the efficiency of solar thin-film modules using optimized cells with different widths was explored, thus enabling the tuning of the output voltage of the solar module while the power output remains unchanged. V C 2015 AIP Publishing LLC.

A strategy for implementation of triangular thin-film photovoltaic modules

“…Therefore, the series resistance caused by the bottom electrode was not considered in the used model. This modeling approach enables the simulation of solar cells with arbitrary shape and metallization geometry (Bednar et al, 2015), and also supports the simulation of curved PV modules (Bednar et al, 2014).…”

“…used in PiPV applications), where the individual cell's length does not exceed 4 mm, there is no need to use the metallization grid (Bednar et al, 2015); the photo-generated current can be collected by TCO layer without introducing severe electrical losses.…”

“…The applied metallization grid has the form of parallel 250 lm thick silver finger lines. The optimization of the distance between the fingers was described in Flat and Milnes (1979) and Bednar et al (2015). In the simulated model the spacing of the fingers was set to 3.6 ± 0.2 mm.…”

Modelling of Cu(In,Ga)Se2 Solar Materials/Devices

“…In order to investigate the possibilities of size of solar devices (cells and modules), types of interconnection and front grid metallization, numerical simulations were carried out. The simulations were built upon the hybrid model of photovoltaic device, which consists of two coupled models: 1D material level model and 3D device level model [10]. The resulting I-V curve of the material simulation is used as an input data for the device based model.…”

Optical Simulation of Light Management in CIGS Thin-Film Solar Cells Using Finite Element Method

“…While for a number of thin-film photovoltaic simulations the application of 1-D models is sufficient [21], the simulation of non-flat cell layers requires the use of 2-D or 3-D models. In some simulations a combination of models can be used to simulate the cells with higher dimensions [22].…”