Heterojunction Cell TCO Edge Isolation for Short-Circuit Control
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Solution Overview
Problem
Heterojunction cells in the related art have low efficiency due to issues such as short circuits between transparent conductive layers and suboptimal current density, leading to efficiency losses.
Innovation Solution
A heterojunction cell design with spaced-apart transparent conductive layers and an insulating isolation layer to prevent short circuits, along with silver nanowire layers and dielectric layers to enhance conductivity and current density, is proposed. The cell structure includes a substrate with intrinsic and doped silicon layers, transparent conductive layers covering the surfaces and lateral surfaces, and an insulating isolation layer to define an isolation region between the conductive layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional heterojunction cell structure is used with continuous transparent conductive layers, then the device complexity is reduced, but edge-induced potential difference and hot carrier effects occur leading to reduced reliability
Solution Approach 1:
The continuous transparent conductive layer is segmented into separate first and second transparent conductive layers with different lateral extensions. The first transparent conductive layer covers only the first surface, while the second transparent conductive layer covers the second surface and extends onto the rear surface, creating spatial separation that eliminates edge-induced potential differences and hot carrier effects.
Solution Approach 2:
The patent introduces a new spatial dimension by extending the second transparent conductive layer onto the rear surface of the substrate, creating a three-dimensional conductive network configuration. This dimensional change allows the conductive layers to be positioned at different locations in space, solving the edge effect problem without requiring complex additional components.
2Use of energy by moving object
If the first transparent conductive layer covers the entire first surface, then the light collection efficiency is improved, but the manufacturing precision becomes difficult to control due to edge overlap issues
Solution Approach 1:
The patent divides the transparent conductive layer coverage into two separate layers with distinct lateral extensions. The first transparent conductive layer is limited to the first surface, while the second transparent conductive layer covers the second surface and extends onto the rear surface. This segmentation eliminates the need for precise edge alignment between layers, as they do not overlap at the edges.
Solution Approach 2:
Each transparent conductive layer is designed with different local coverage characteristics tailored to its specific function. The first layer provides full first surface coverage for optimal light collection, while the second layer extends onto the rear surface to provide additional functionality. This local quality differentiation allows each layer to be optimized independently without manufacturing precision constraints.
3Reliability
If no isolation region is provided between transparent conductive layers, then the device complexity is reduced, but edge-induced potential difference and hot carrier effects reduce the cell's reliability
Solution Approach 1:
The patent inherently creates an isolation region by segmenting the transparent conductive layers such that the first layer is limited to the first surface and the second layer extends onto the rear surface. This spatial segmentation automatically generates an isolation region between the layers, eliminating edge-induced potential differences and hot carrier effects without requiring additional isolation structures.
Solution Approach 2:
The substrate's rear surface acts as an intermediary space that the second transparent conductive layer extends onto, creating a physical separation zone between the first and second transparent conductive layers. This intermediary region serves as an isolation zone that prevents harmful electrical interactions while maintaining the simplicity of the overall device structure.
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 solution effectively isolates the transparent conductive layers, preventing short circuits and improving current density, thereby enhancing the efficiency of the heterojunction cell by minimizing efficiency loss and maximizing fill factor.
Implementation Method 1
a first intrinsic silicon layer (20), a first doped layer (30), and a first transparent conductive layer (40) that are sequentially stacked on a first surface (F); and a second intrinsic silicon layer (50), a second doped layer (60), and a second transparent conductive layer (70) that are sequentially stacked on a second surface (S)
Data Source
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AI summary
The present disclosure relates to a heterojunction cell (100) and a manufacturing method thereof, a photovoltaic module and a photovoltaic system. The heterojunction cell (100) includes: a substrate (10); a first intrinsic silicon layer (20), a first doped layer (30), and a first transparent conductive layer (40) that are sequentially stacked on a first surface (F); and a second intrinsic silicon layer (50), a second doped layer (60), and a second transparent conductive layer (70) that are sequentially stacked on a second surface (S). A doping type of the first doped layer (30) is opposite to a doping type of the second doped layer (60). The first transparent conductive layer (40) covers at least part of the first surface (F). The second transparent conductive layer (70) covers the second surface (S) and at least part of the plurality of lateral surfaces (C). An edge (41) of the first transparent conductive layer (40) is spaced apart from an edge (71) of the second transparent conductive layer (70), to define an isolation region (81) therebetween.