Solar Cell Bus Electrode Design Reducing Metal Recombination
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Solution Overview
Problem
The efficiency of solar cells is reduced due to high metal recombination on their surfaces, primarily because metal bus electrodes are in direct contact with the semiconductor substrate.
Innovation Solution
A solar cell design featuring first and second conductive contact layers with specific dimensions and orientations relative to bus and collector electrodes, reducing direct contact between the bus electrodes and the semiconductor substrate, and incorporating these layers to minimize recombination and enhance current collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If bus electrodes are made of metal and placed directly on the semiconductor substrate to collect current, then current collection capability is improved, but metal recombination increases and efficiency decreases
Solution Approach 1:
The patent introduces a conductive contact layer as an intermediary between the metal bus electrode and the semiconductor substrate. This contact layer serves as a mediator that enables current collection while preventing direct metal-substrate contact that causes recombination loss. The conductive contact layer is formed by screen printing conductive paste and firing it to create a metallization layer that bridges the electrode and substrate.
Solution Approach 2:
The patent segments the electrode structure into multiple components: the metal bus electrode, the conductive contact layer, and the semiconductor substrate. By dividing the direct contact interface into separate functional layers, the system achieves both current collection and reduced recombination. The conductive contact layer is patterned with specific width and spacing to optimize both electrical performance and light absorption.
2Loss of energy
If conductive contact layers are added between bus electrodes and semiconductor substrate to reduce metal recombination, then energy loss is reduced, but device complexity increases
Solution Approach 1:
The patent optimizes parameters of the conductive contact layer including its width (5-20 μm), spacing (100-500 μm), and firing temperature to achieve the desired balance between reducing recombination and maintaining simplicity. By carefully controlling these parameters, the contact layer provides the necessary functionality without excessive complexity in 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
This design reduces metal recombination, increases open-circuit voltage, and enhances overall solar cell efficiency by minimizing contact resistivity and series resistance while optimizing current collection and transport.
Implementation Method 1
A solar cell is a device that uses solar energy and directly converts light energy into electrical energy by using a photoelectric effect or a photochemical effect
Data Source
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AI summary
The present application discloses a solar cell and a method for manufacturing a solar cell, and relates to the field of solar cell technologies, to resolve a problem that bus electrodes made of metal are completely in direct contact with a semiconductor substrate, resulting in high metal recombination on a surface of the solar cell and reduction of efficiency of the solar cell. The solar cell includes: a semiconductor substrate, first conductive contact layers, bus electrodes, and collector electrodes. The first conductive contact layers are formed on at least one surface of the semiconductor substrate, extend in a first direction, and are spaced apart in a second direction. The bus electrodes are formed over the first conductive contact layers, and disposed on at least one surface of the semiconductor substrate. The bus electrodes extend in the first direction and are spaced apart in the second direction. A projection of at least one of the first conductive contact layers on the semiconductor substrate overlaps with a projection of the bus electrodes on the semiconductor substrate, and the first direction is different from the second direction.