Passivated Solar Cell Contact Structure for Lower Surface Recombination
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Solution Overview
Problem
Conventional passivated contact structures in solar cells have discontinuous structures and poor integrity, leading to poor surface passivation effects and reduced conversion efficiency due to high recombination rates.
Innovation Solution
A solar cell design featuring a passivated contact structure with a first tunnel oxide layer, a polysilicon doped conductive layer, and a second tunnel oxide layer, where holes are formed in the polysilicon doped conductive layer and first tunnel oxide layer, and the second tunnel oxide layer fills these holes, enhancing surface passivation and continuity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional passivated contact structure with a single tunnel oxide layer and polysilicon layer is used, then the manufacturing process is simple, but the surface passivation effect is poor due to discontinuous structure
Solution Approach 1:
The single tunnel oxide layer and polysilicon layer are segmented into two separate pairs: a first tunnel oxide layer (10) with a first polysilicon doped conductive layer (30), and a second tunnel oxide layer (20) with a second polysilicon doped conductive layer (30). This segmentation allows each layer to perform its function more effectively, with the first tunnel oxide layer providing chemical passivation and the second tunnel oxide layer ensuring structural continuity, thereby resolving the contradiction between simple manufacturing and effective passivation.
Solution Approach 2:
The patent introduces a vertical stacking dimension by arranging the first and second tunnel oxide layers and polysilicon layers in sequence from bottom to top. This dimensional arrangement allows the first tunnel oxide layer to provide chemical passivation at the substrate interface while the second tunnel oxide layer provides structural continuity at the upper interface, simultaneously achieving both passivation effectiveness and structural integrity without increasing lateral complexity.
2Productivity
If a conventional passivated contact structure is used, then the manufacturing process is straightforward, but the conversion efficiency is reduced due to high recombination rates
Solution Approach 1:
The contact structure is segmented into functional zones: the first tunnel oxide layer (10) and first polysilicon layer (30) handle carrier tunneling and chemical passivation, while the second tunnel oxide layer (20) and second polysilicon layer (30) provide additional passivation and reduce recombination. This functional segmentation minimizes energy loss from recombination while maintaining manufacturing feasibility, thereby improving conversion efficiency.
Solution Approach 2:
The first and second tunnel oxide layers act as intermediary barrier layers between the silicon substrate and the polysilicon doped conductive layers. These intermediary layers reduce direct contact between the substrate and polysilicon, minimizing recombination sites and energy loss, while still allowing necessary carrier tunneling to occur.
3Stability of the object's composition
If a single-layer passivated contact structure is used, then the manufacturing steps are fewer, but the structural integrity is poor
Solution Approach 1:
The patent merges two complete tunnel oxide-polysilicon pairs into a single integrated passivated contact structure. The first tunnel oxide layer (10) combines with the first polysilicon layer (30), and the second tunnel oxide layer (20) combines with the second polysilicon layer (30), creating a unified multi-layer structure that achieves high structural integrity while maintaining manufacturing efficiency through integrated processing steps.
Solution Approach 2:
The first tunnel oxide layer (10) and first polysilicon layer (30) are formed first to establish the base passivation structure, followed by the formation of the second tunnel oxide layer (20) and second polysilicon layer (30) to complete the structure. This preliminary action sequence ensures that each layer is properly prepared and positioned before the next layer is added, achieving high structural integrity through systematic layer-by-layer construction.
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 improved surface passivation reduces surface recombination and increases the conversion efficiency of the solar cell by ensuring a continuous and effective tunneling function across the substrate surface.
Implementation Method 1
an interface recombination between the silicon substrate and the polysilicon is reduced by means of chemical passivation effect of the tunnel oxide layer
Implementation Method 2
the tunnel oxide layer may also perform a relatively good tunneling function, so that most carriers are transported according to a tunneling principle
Data Source
AI summary
A solar cell and a manufacturing method thereof, a photovoltaic module, and a photovoltaic system. The solar cell includes a substrate and a passivated contact structure. The passivated contact structure includes a first tunnel oxide layer, a polysilicon doped conductive layer, and a second tunnel oxide layer sequentially disposed on a surface of the substrate. A plurality of holes arranged spaced apart from each other are formed in at least a part of regions of the polysilicon doped conductive layer and the first tunnel oxide layer. Each of the holes extends through the polysilicon doped conductive layer and extends into the first tunnel oxide layer. The second tunnel oxide layer at least fills a portion of each of the holes that is located within the first tunnel oxide layer.