Holistic Device-to-Module Modelling (PP4.2)

PP4.2: Holistic Device-to-Module Modelling

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Investigators: Dr Marco Ernst

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This topic will focus on developing, validating, and applying holistic device-to-module models. The benefit of this modelling approach which includes the development of dedicated tools, in that it enables rapid evaluation and comparison of performance by virtual prototyping of an arbitrarily large number of module technologies and designs in much less time than would be possible through experimental work.

 

The objectives of this activity are to optimize technology-specific module designs, improve module optics and bifaciality, support process and technology optimization, and ultimately increase the module performance in systems under realistic outdoor conditions to reduce the LCOE. This activity will perform a technology-neutral assessment of the material, device and module technologies developed within ACAP, and benchmark their performance in terms of their power and energy yield.

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The performance of solar cells and modules is usually measured and reported under standard test conditions at a constant cell temperature and defined spectral illumination. Critical to the end-user and thus the acceptance of a new technology, however, is a reliable prediction of the expected real-world gains in energy yield compared to existing technology.

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This activity will extend the cell-to-module yield modelling capabilities at ANU to enable the evaluation and optimisation of novel device and module technologies developed within ACAP, including bifacial and tandem technologies, for their real-world performance. The five-dimensional (three-dimensional space, plus spectral and time dimension) modelling approach considers internal and external optical effects which will, for example, allow for improving of advanced cell metallisation and module designs and enable detailed assessment of the performance impact of individual components in the module.

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By means of cell-to-module yield modelling it has been demonstrated that installation scenarios can have a significant impact on the optimum interconnector designs in silicon solar modules.

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Crucially, the holistic model will take environmental factors into account. Solar modules are deployed in a range of locations and climatic conditions. For example, the modules receive radiation from different directions with varying spectra. Bifacial modules, in particular, are affected by the intensity and spectrum of ground radiation. Environmental factors can affect the optimal module design, especially for tandem modules, due to differences in spectral response and temperature coefficients of the sub-cells.

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The fundamental design considerations, for example, in the development of tandem modules are the electrical and optical configuration, i.e., two- or four-terminals. In the monolithic two-terminal design, the top and bottom sub-cells are electrically connected in series. Critically, this approach requires current matching in the two sub-cells to achieve the highest efficiency which is heavily impacted by the local spectral conditions. This effect is even stronger for bifacial tandem modules where the bottom cell receives additional ground reflected radiation.

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In contrast, silicon and perovskite cells operate independently as two sub-modules in the four-terminal design. The four-terminal design has the advantage that it is independent of current mismatch and thus practically removes the narrow bandgap limitation on the top cell. However, either additional electronics for each sub-module or voltage-matching is required.

 

The latter is susceptible to losses from differences in the voltage-temperature coefficients. A detailed model that takes the optical, electrical, and thermal material and device properties, module interconnection as well as environmental factors into account is therefore needed to evaluate the performance of novel technologies and optimize module designs.

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To achieve the objectives of this activity, the inputs to the holistic device-to-module modelling will be measurable material parameters, electrical device characteristics, and local time-resolved weather data. The model outputs will be a detailed device-to-module loss analysis resolving the impact of individual components, the total expected module output power and energy yield for any specified location.

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Objectives

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• Develop a technology-neutral device-to-module modelling framework based on measurable material properties and device characteristics and weather data enabling rapid virtual prototyping of solar modules.

• Initiate collaboration opportunities in the area of characterization and by applying the holistic modelling approach for supporting technology optimization at the respective nodes.

• Create a catalogue of the expected field performance impact of pivotal device and module technologies developed within ACAP considering available module design choices.