Back Electrode Silicon Distribution in Solar Cells
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Solution Overview
Problem
Existing solar cells face inefficiencies due to void generation between the back electrode layer and the substrate during the firing process, leading to increased contact resistance and reduced photoelectric efficiency.
Innovation Solution
Incorporating silicon material into the back electrode layer, either throughout its surface or in specific portions, to prevent void formation and enhance the distribution of silicon, thereby improving the contact resistance and fill factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aluminum paste is heated to form aluminum silicide in the back electrode layer, then electrical connection to the substrate is achieved, but voids are generated between the back electrode layer and substrate leading to increased contact resistance
Solution Approach 1:
The patent changes the chemical composition parameters of the back electrode layer by incorporating silicon material (6-15 wt%) into the aluminum paste formulation. This parameter modification prevents void formation during the firing process while maintaining electrical connectivity, thereby reducing contact resistance without sacrificing connection reliability
Solution Approach 2:
The patent creates a composite back electrode layer material combining aluminum with silicon particles or beads. This composite structure prevents the harmful void formation that occurs with pure aluminum paste while ensuring reliable electrical contact between the back electrode layer and substrate
2Ease of manufacture
If aluminum paste is used to form the back electrode layer, then manufacturing process is simple, but photoelectric efficiency is reduced due to void generation
Solution Approach 1:
The patent modifies the paste composition parameters by adding silicon material to the aluminum paste, creating an optimized formulation that maintains ease of manufacturing through standard screen printing and firing processes while significantly improving photoelectric efficiency by eliminating void-related energy losses
3Object-affected harmful factors
If silicon material is added to the back electrode layer, then void generation is reduced and contact resistance decreases, but manufacturing complexity increases
Solution Approach 1:
The patent optimizes the silicon content parameter within a specific range (6-15 wt%) to achieve the desired effect of reducing void generation. This controlled parameter change balances performance improvement with manufacturing feasibility, avoiding excessive complexity while achieving the technical goal
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 integration of silicon in the back electrode layer reduces void generation, increases output voltage and fill factor, and enhances the overall photoelectric efficiency of the solar cell.
Implementation Method 1
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
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AI summary
A solar cell includes a substrate of a first conductive type, an emitter layer which is positioned at an incident surface of the substrate and has a second conductive type opposite the first conductive type, a front electrode which is positioned on the incident surface of the substrate and is electrically connected to the emitter layer, a back passivation layer which is positioned on a back surface opposite the incident surface of the substrate, has at least one hole, and contains intrinsic silicon, and a back electrode layer positioned on the back passivation layer. The back electrode layer is electrically connected to the substrate through the at least one hole of the back passivation layer and contains a distribution of a silicon material.