Solar Cell Electrode Segmentation for Lower Series Resistance
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Solution Overview
Problem
Solar cells exhibit high series resistance due to the limiting effect of tunneling oxide layers on carrier transport, which compromises their efficiency and performance.
Innovation Solution
A solar cell design featuring a first metal electrode that does not penetrate the tunneling oxide layer and a second metal electrode that penetrates through it to contact the substrate, combined with a local doped region of higher doping concentration, to enhance carrier transport while maintaining passivation effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a tunneling oxide layer is prepared on the substrate surface to enhance passivation effect, then the chemical passivation effect is improved, but the carrier transport capability is limited resulting in high series resistance
Solution Approach 1:
The electrode structure is segmented into two distinct parts: a first metal electrode that does not penetrate the tunneling oxide layer to maintain passivation, and a second metal electrode that penetrates through the tunneling oxide layer to provide low-resistance carrier transport. This segmentation allows each electrode component to fulfill its specific function without compromising the other.
Solution Approach 2:
Different regions of the electrode structure are assigned different properties: the first metal electrode region maintains high passivation quality by not penetrating the oxide layer, while the second metal electrode region provides high conductivity by penetrating the oxide layer. This local differentiation of properties resolves the contradiction between passivation and conductivity requirements.
2Reliability
If the tunneling oxide layer thickness is increased to improve passivation, then the chemical passivation effect is enhanced, but the carrier tunneling capability is reduced leading to higher series resistance
Solution Approach 1:
The electrode is divided into two functional segments that interact differently with the tunneling oxide layer. The first metal electrode segment preserves the oxide layer integrity for passivation, while the second metal electrode segment creates controlled penetration paths for carrier transport, effectively decoupling the thickness constraints from the overall system performance.
Solution Approach 2:
The system changes the structural parameter of the electrode from a single-layer configuration to a two-layer configuration with different penetration depths. This parameter change allows the tunneling oxide layer to maintain its optimal thickness for passivation while the penetrating electrode provides alternative carrier transport pathways.
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 design reduces series resistance and improves carrier transport efficiency, enhancing the overall performance of the solar cell by maintaining the passivation capabilities of the tunneling oxide layer.
Implementation Method 1
the tunneling oxide layer has better chemical passivation effect
Implementation Method 2
the doped conductive layer has better field passivation effect
Implementation Method 3
the second metal electrode penetrates through the tunnelling oxide layer to be in contact with the substrate, so that the transport of carriers done by the second metal electrode is not limited by the tunnelling oxide layer
Implementation Method 4
a solar cell has a desirable photoelectric conversion capability
Data Source
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AI summary
The embodiments of the present disclosure relate to the technical field of solar cells, and in particular, to a solar cell, a method for preparing the solar cell, and a photovoltaic module. The solar cell includes: a substrate, having a first surface; a tunnelling oxide layer, a doped conductive layer and a first passivation layer that are provided on the first surface of the substrate sequentially in a direction away from the substrate; a first metal electrode and a second metal electrode, where the first metal electrode penetrates through the first passivation layer to be electrically connected to the doped conductive layer, the second metal electrode is connected to a surface of the first metal electrode facing toward the substrate, the second metal electrode penetrates through the tunnelling oxide layer to be in contact with the substrate, and the width of the second metal electrode is smaller than the width of the first metal electrode; a local doped region, where the local doped region is located in the substrate, and covers the second metal electrode located in the substrate; the local doped region and the substrate have doping elements of a same conductivity type, and the doping concentration of the local doped region is greater than the doping concentration of the substrate. The embodiments of the present disclosure are beneficial to reducing the series resistance of the solar cell.