Photovoltaic Cell Native Edge Passivation for Shingle Sub-Cells
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Solution Overview
Problem
The efficiency of photovoltaic sub-cells decreases as their dimensions are reduced, particularly in shingle interconnection technology, due to inadequate passivation of native edges which are prone to shocks and have lower intrinsic passivation quality compared to upper and lower surfaces.
Innovation Solution
A method of manufacturing photovoltaic cells that involves removing the native edges' active layers and replacing them with passivation layers of lower surface recombination speed, such as aluminum oxide, to enhance the quality of passivation and reduce electrical losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the dimensions of photovoltaic sub-cells are reduced for shingle interconnection technology, then the area and power output are reduced, but the efficiency losses due to inadequate native edge passivation become more significant
Solution Approach 1:
The patent applies different passivation qualities to different regions: the native edges receive enhanced passivation treatment with specific layer configurations (intrinsic and doped a-Si:H layers) while the central active region maintains its standard structure. This local differentiation addresses the specific problem of edge recombination without compromising the overall cell design
Solution Approach 2:
The passivation layers are formed on the native edges before the sub-cells are separated through scribing and splitting. This preliminary passivation ensures that the edges are protected against contamination and degradation during subsequent processing steps, maintaining optimal passivation quality
2Ease of manufacture
If the native edges are retained in the initial photovoltaic cell, then the manufacturing process is simpler, but the passivation quality is insufficient and the edges are sensitive to shocks and contamination
Solution Approach 1:
The patent implements a protective passivation structure on the native edges before any potential damage can occur. The combination of intrinsic and doped a-Si:H layers creates a cushioning effect that protects the sensitive silicon edges from mechanical shocks and chemical contamination during handling and operation
Solution Approach 2:
The patent modifies the passivation parameters by forming specific layer configurations with controlled thicknesses (e.g., intrinsic layer 5-20 nm, doped layer 50-200 nm) and doping concentrations (10^19 to 10^21 atoms/cm³). These parameter changes enhance the passivation quality while maintaining process compatibility
3Device complexity
If standard passivation layers are used on all surfaces, then the manufacturing process is uniform and simple, but the native edges have lower intrinsic passivation quality compared to upper and lower surfaces
Solution Approach 1:
The patent segments the passivation approach by treating native edges differently from the upper and lower surfaces. The native edges receive a specific two-layer a-Si:H configuration while other surfaces may use different passivation schemes, allowing optimization for each region's specific requirements
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
This method improves the efficiency of photovoltaic sub-cells by up to 0.1% per native edge replaced, reducing sensitivity to shocks and contamination, and eliminating electrical shading losses.
Implementation Method 1
Passivation of substrate surfaces is a major challenge in the photovoltaic sector, making it possible to limit recombinations between minority and majority carriers
Implementation Method 2
The invention relates to the technical field of photovoltaic cells
Data Source
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AI summary
Method for manufacturing a photovoltaic cell, comprising the steps: a) using an initial photovoltaic cell, comprising: - a substrate (1), based on crystalline silicon, and having: first and second opposite lateral edges, third and fourth opposite lateral edges, connecting the first and second lateral edges; - a stack (2) of active layers (20), formed around the substrate (1), and comprising an initial passivation layer (P0) having an effective surface recombination velocity, denoted SRV0.