Passivated Solar Cell Edge Holes for Lower Recombination
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Solution Overview
Problem
Current solar cells face issues with poor photoelectric conversion efficiency due to surface defects and recombination rates, which are exacerbated by the formation of back contact passivation structures during the preparation process.
Innovation Solution
The solar cell design includes a doped semiconductor layer with edge regions containing holes filled with a passivation material and electrodes that extend through the passivation layer, providing enhanced passivation and reducing structural stress, thereby improving the cell's efficiency and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a passivation contact structure is prepared on the silicon substrate surface to reduce carrier recombination rate, then the open circuit voltage and fill factor increase, but surface defects and recombination rates are exacerbated by the formation process
Solution Approach 1:
The patent divides the back contact structure into multiple segments: a first doped semiconductor layer, a second doped semiconductor layer, and multiple isolated contact regions. This segmentation allows each layer to perform specialized functions - the first layer provides passivation while the second layer provides contact, reducing surface defects and recombination rates simultaneously
Solution Approach 2:
The patent applies different doping types and concentrations to different regions of the back contact structure. The first doped semiconductor layer has one doping type while the second layer has another, creating local quality variations that optimize both passivation performance and electrical contact properties, thereby reducing surface defects and carrier recombination
2Productivity
If LPCVD is used to prepare the tunneling oxide layer and polysilicon layer, then low cost and high yield are achieved, but problems in the preparation process affect cell efficiency
Solution Approach 1:
The patent modifies the preparation parameters by using specific doping concentrations and layer thicknesses in the LPCVD process. The first doped semiconductor layer uses a first doping concentration while the second layer uses a second doping concentration, optimizing both the yield and efficiency by fine-tuning process parameters
Solution Approach 2:
The patent creates a composite structure with multiple doped semiconductor layers having different properties. This composite approach combines the advantages of LPCVD (low cost, high yield) with improved efficiency by using material composition variations to optimize both production and performance
3Productivity
If electrodes are formed on the doped semiconductor layer to collect carriers, then carrier collection is improved, but the doped semiconductor layer may break during electrode formation and module lamination
Solution Approach 1:
The patent segments the contact structure into multiple isolated contact regions rather than continuous contacts. This segmentation reduces the mechanical stress on any single region during electrode formation and lamination, preventing breakage while maintaining effective carrier collection across the surface
Solution Approach 2:
The patent creates local quality variations with different doped layers having different mechanical and electrical properties. The first doped layer provides mechanical support while the second doped layer optimizes electrical contact, creating a structure that is both strong and conductive, preventing breakage during processing
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design reduces surface defects and recombination rates, enhances the structural integrity of the doped semiconductor layer, and improves the photoelectric conversion efficiency by facilitating better carrier collection and reducing the chance of breakage during electrode formation and module lamination.
Implementation Method 1
a chemical passivation of the tunneling oxide layer and a field passivation of the polysilicon layer may be utilized to significantly reduce a recombination rate of minority carriers
Implementation Method 2
a chemical passivation of the tunneling oxide layer and a field passivation of the polysilicon layer may be utilized to significantly reduce a recombination rate of minority carriers
Implementation Method 3
the highly doped polysilicon layer can significantly improve an electric conductivity property of majority carriers
Implementation Method 4
A solar cell is an apparatus that converts light energy of the sun into electric energy. The solar cell generates carriers by using a photovoltaic effect principle
Data Source
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AI summary
Disclosed are a solar cell and a photovoltaic module. The solar cell includes a substrate and a doped semiconductor layer disposed on the substrate. The solar cell further includes holes distributed across an edge region of the doped semiconductor layer, and a respective hole of the holes extending through at least the doped semiconductor layer and being filled with a passivation material. The solar cell further includes a passivation layer formed on a side of the doped semiconductor layer away from the substrate, and a plurality of electrodes arranged at intervals along a first direction, extending through the passivation layer and in electrical contact with the doped semiconductor layer.