Solar Cell Passivation Stack for PID-Resistant High-Throughput Production
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Solution Overview
Problem
Current solar cells with aluminum oxide/silicon nitride (AlOx/SiNx) stack passivation layers face high equipment costs, low production capacity, and potential induced degradation (PID) issues, which hinder industrial mass production and reduce the service life and performance of photovoltaic modules.
Innovation Solution
A solar cell with a passivation film stack comprising a silicon-rich layer, an oxygen-rich and nitrogen-rich layer, and a silicon nitride layer with a gradient-varied refractive index is used, replacing the conventional AlOx/SiNx stack, which enhances back passivation characteristics and reduces PID while lowering manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aluminum oxide/silicon nitride (AlOx/SiNx) stack is used as back passivation layer, then passivation effect is improved, but equipment cost increases and production capacity decreases
Solution Approach 1:
The invention changes the material composition parameters by replacing AlOx with silicon-rich silicon oxynitride carbide (SiOx-yCzNy) having specific compositional ranges (x=0.5-2.0, y=0.1-0.5, z=0.1-0.5). This parameter change maintains the passivation function while enabling more efficient production processes and higher throughput, thus improving production capacity without sacrificing passivation quality.
Solution Approach 2:
The invention employs composite material structure by creating silicon-rich silicon oxynitride carbide that combines multiple elements (Si, O, C, N) in specific ratios. This composite approach achieves superior passivation characteristics comparable to or better than AlOx/SiNx stacks while being compatible with more economical and higher-capacity manufacturing equipment, thereby resolving the contradiction between reliability and productivity.
2Reliability
If aluminum oxide/silicon nitride (AlOx/SiNx) stack is used as back passivation layer, then passivation effect is improved, but manufacturing cost increases
Solution Approach 1:
The invention modifies the material parameters by substituting expensive AlOx with silicon-rich silicon oxynitride carbide having optimized compositional parameters (x=0.5-2.0, y=0.1-0.5, z=0.1-0.5). This parameter optimization achieves effective passivation using more cost-effective materials and processes, directly reducing manufacturing costs while maintaining or improving passivation quality.
Solution Approach 2:
The invention adopts a more economical material approach by using silicon-rich silicon oxynitride carbide that can be deposited using standard, widely-available equipment rather than specialized expensive equipment required for AlOx. This substitution with more affordable materials and processes reduces manufacturing costs while achieving the required passivation performance.
3Ease of manufacture
If conventional passivation layers are used, then manufacturing is simpler, but PID resistance is poor
Solution Approach 1:
The invention uses composite silicon-rich silicon oxynitride carbide material that inherently provides superior PID resistance due to its unique compositional structure. The material's specific composition (with carbon and nitrogen components) creates a more stable interface that prevents ion migration and degradation, thereby improving reliability without significantly complicating the manufacturing process.
Solution Approach 2:
The invention changes the material composition parameters to silicon-rich silicon oxynitride carbide with specific ratios (x=0.5-2.0, y=0.1-0.5, z=0.1-0.5), which provides enhanced chemical stability and resistance to potential-induced degradation. This parameter optimization maintains manufacturing simplicity while dramatically improving PID resistance compared to conventional passivation layers.
4Reliability
If aluminum oxide film is used for field effect passivation, then carrier recombination is suppressed, but production efficiency decreases
Solution Approach 1:
The invention changes the passivation layer material parameters from AlOx to silicon-rich silicon oxynitride carbide with optimized composition (x=0.5-2.0, y=0.1-0.5, z=0.1-0.5). This parameter change maintains the field effect passivation capability that suppresses carrier recombination while enabling deposition processes that are more compatible with high-volume manufacturing, thus improving production efficiency without compromising reliability.
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 new passivation film stack effectively enhances back passivation, reduces PID, and lowers manufacturing costs, improving the efficiency and reliability of solar cells without using AlOx, thus addressing the limitations of existing technologies.
Implementation Method 1
An aluminum oxide film contains a high fixed negative charge density, and a large number of fixed negative charges may shield electrons on a silicon surface, thereby reducing electrons that can be used for recombination and thus achieving a purpose of suppressing carrier recombination on the surface. Due to the high fixed negative charge density, a strong field passivation effect may be generated
Implementation Method 2
A main reason for the potential induced degradation lies in that Na+ ions inside glass of an encapsulating material of the photovoltaic (PV) module migrate to inside of the solar cell along a direction of the solar cell to destroy a p-n junction
Data Source
AI summary
Provided is a solar cell. The solar cell may include a semiconductor layer and a passivation film stack provided on a back surface of the semiconductor layer. The passivation film stack may include a first passivation layer provided on the back surface of the semiconductor layer and including a silicon-rich layer with a silicon atom concentration ranging from 5×1021/cm3 to 2.5×1022/cm3; a second passivation layer provided on a surface of the first passivation layer and including an oxygen-rich and nitrogen-rich layer; and a third passivation layer provided on a surface of the second passivation layer and including at least one silicon nitride film with a gradient-varied refractive index. A first refractive index of the first passivation layer may be greater than a second refractive index of the second passivation layer and smaller than a third refractive index of the third passivation layer.