Back-Surface Electrode Solar Cell Design
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Solution Overview
Problem
Conventional solar cells have reduced efficiency due to the formation of electrodes on both the incident and non-incident surfaces of the substrate, which decreases the light incident area and affects energy conversion efficiency.
Innovation Solution
A solar cell design featuring a substrate with a textured front surface, an anti-reflection layer made of transparent conductive oxide, and strategically positioned emitter and back surface field layers, along with electrodes on the back surface, optimized by forming passivation layers and insulating portions to enhance light absorption and reduce recombination, while maintaining low process temperatures to prevent damage to existing layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrodes are formed on both the incident and non-incident surfaces of the substrate, then electrode collection function is improved, but light incident area decreases and efficiency is reduced
Solution Approach 1:
The patent inverts the conventional electrode arrangement by moving all electrodes to the back surface of the substrate. Instead of having electrodes on both front and back surfaces, the invention places both the first electrodes (collecting one type of carrier) and second electrodes (collecting the other type of carrier) on the back surface, thereby eliminating the occupation of front surface area by electrodes and maximizing light incident area.
2Loss of energy
If anti-reflection layer is formed to reduce reflection losses, then light absorption is improved, but process temperature increases which may damage existing layers
Solution Approach 1:
The patent employs a composite anti-reflection layer structure consisting of multiple materials with different refractive indices (e.g., silicon nitride and silicon oxide layers). This multi-layer composite structure achieves superior anti-reflection performance compared to single-layer designs, allowing for reduced overall process temperature while maintaining effective light absorption.
3Area of stationary object
If emitter layers are positioned on the back surface to increase light incident area, then light absorption is improved, but carrier recombination may increase
Solution Approach 1:
The patent implements local quality differentiation by creating distinct functional regions on the back surface. Emitter layers are positioned in specific areas optimized for carrier collection, while passivation layers are applied in other regions to minimize recombination. The first and second electrodes are strategically placed to collect different types of carriers efficiently, ensuring that each local area serves its optimal function.
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 increases light absorption and reduces reflection losses, improving solar cell efficiency by maximizing the light incident area and preventing carrier recombination, thereby enhancing energy conversion efficiency.
Implementation Method 1
an anti-reflection layer positioned on the substrate, the anti-reflection layer being formed of a transparent conductive oxide material
Implementation Method 2
When light is incident on the solar cell, a plurality of electron-hole pairs are generated in the semiconductors. The electron-hole pairs are separated into electrons and holes by the photovoltaic effect.
Data Source
Figure 1
Figure 2A~2C
Figure 2D~2F
AI summary
A solar cell and a method for manufacturing the same are disclosed. The solar cell includes a substrate of a first conductive type, an anti-reflection layer that is positioned on the substrate and is formed of a transparent conductive oxide material, a plurality of emitter layers on the substrate, the plurality of emitter layers being of a second conductive type opposite the first conductive type, a plurality of first electrodes on the plurality of emitter layers, and a plurality of second electrodes that are electrically connected to the substrate and are positioned to be spaced apart from the plurality of first electrodes. The first electrodes and the second electrodes are positioned on the same surface of the substrate.