Numerical simulation and experimental characterization of c-Si cells mechanical limits in spherical curvature shape

International audienceTo ensure the mechanical strength of the cells in shaped photovoltaic modules, it is important to know their double bending radius limit, as well as their mechanical breaking limits.This study focuses on the mechanical characterization of Si cells under double curvature load. It aims at determining the mechanical limits of silicon under double curvature, as well as the minimum radii of curvature reachable without breaking the cell.A numerical model representing the curvature of a cell in a double-curvature wedge has been implemented. It aims at predicting, for a given cell thickness, the acceptable double radius limit. This numerical model is validated with experimental tests to quantify the mechanical limits of silicon under double curvature. Experimental tests were performed on different types of cells -wafers, cells with or without interconnections- to evaluate the impact of each process step on the mechanical strength of cells under this double curvature load

In situ monitoring of electrical parameters of PV modules under mechanical stress

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PV integration in curved parts: mechanical limits and key parameters from a theoretical point of view

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Overview and Perspectives for Vehicle-Integrated Photovoltaics

On-board photovoltaic (PV) energy generation is starting to be deployed in a variety of vehicles while still discussing its benefits. Integration requirements vary greatly for the different vehicles. Numerous types of PV cells and modules technologies are ready or under development to meet the challenges of this demanding sector. A comprehensive review of fast-changing vehicle-integrated photovoltaic (VIPV) products and lightweight PV cell and module technologies adapted for integration into electric vehicles (EVs) is presented in this paper. The number of VIPV projects and/or products is on a steady rise, especially car-based PV integration. Our analysis differentiates projects according to their development stage and technical solutions. The advantages and drawbacks of various PV cell and module technologies are discussed, in addition to recommendations for wide-scale deployment of the technologies

VIPV: Thermocompression process development and simulation to integrate photovoltaic cells in a double-curved composite structure

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Process development of integrated photovoltaic cells in a double-curved composite structure for Vehicle-Integrated PhotoVoltaics (VIPV) application

National audienceTopics and investigations The automotive industry is changing to lightweight materials and more energy-efficient vehicles. PV modules have a potential market in this transition. Rigid PV panels integrating silicon cells built directly into the car body outperform thin flexible solar films in terms of efficiency and reliability. To increase the integration of PV modules into the car, the use of composite materials is an interesting option, as they offer an efficient combination of mechanical performances and lightweight. However, the high heterogeneity of the components, the impermeability of the cells and the necessary achievement of certain optical characteristics make it necessary to adapt the usual manufacturing processes of composite panels. Thus, this study focuses on the adaptation of manufacturing processes for the production of composite double-curved PV modules. Moreover, it treats with a coupled numerical and experimental approach the aspect of thermomechanical stresses resulting from these processes. Methods Two processes are being developed, that use composite materials and not only polymers or glass, like most VIPV actors do. These processes-thermocompression and Resin Transfer Molding (RTM)are more adapted to the automotive industry constraints than lamination. As a first step towards the development of the RTM process, the early prototypes were produced using vacuum bagging process, which facilitates the selection of materials and stacks for injection processes. A new numerical model is developed with a Finite Element Analysis to optimize the process parameters and the layup for a one-cell composite PV module. Results A double curved composite PV module was manufactured using vacuum bagging process. This step enabled to select the most appropriate materials and process parameters for the RTM process, in terms of transparency, adhesion between the encapsulant and plies, diffusion of the resin, ageing behavior … A first numerical model (Figure 2) was developed. This model is validated by 3-point bending tests. The correlation between tests and numerical simulation is very good, with a relative error of around 5%. The thermocompression process is under development. It still represents a challenge in terms of residual stresses resulting from thermomechanical loading. The ongoing developments on the numerical model aim at optimizing the stack and thermocompression parameters to minimize these stresses. Conclusions and perspectives Two processes are developed. This work enabled to size a double-curved PV module with composite front and back sheets. It is applicable to either the automotive industry or any application needing lightweight and curved PV modules. The experimental tests validate the mechanical model and provide other properties like the photoelectric performance and the ageing behaviour of these curved panels with respect to IEC61215 standard. Further researches include the optimization of the composite layout and processes parameters to minimize weight while keeping high mechanical strength, as well as the optimization of the reliability and performance of the module

VIPV: Process development of integrated photovoltaic cells in a double-curved composite structure for automotive application

International audienceIn response to the marked increase in research activity and publications about Vehicle Integrated PhotoVoltaics (VIPV), this article is an attempt to identify the main constraints relative to the manufacturing of curved PV modules for automotive application and the interests of composite modules in this context. Two processes have been selected as better adapted to the automotive industrialization and in-mold integration of PV cells: Resin Transfer Molding (RTM) and thermocompression. A finite element analysis (FEA) to evaluate the mechanical strength of the resulting module is proposed. The aim of this numerical approach is to optimize the mechanical performance of the structure. First results were validated by a comparison of simulation outputs with 3-point bending test measurements

Développement d'un procédé de thermocompression permettant d'intégrer des cellules photovoltaïques dans une pièce à double courbure : modélisation et mise en oeuvre

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