Solar Cell Atomic-Layer Oxide Coating for PID Resistance
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Solution Overview
Problem
Photovoltaic modules are prone to potential induced degradation (PID) due to alkali metal ions migrating through the reflection reduction film and into the cell, causing power degradation and reducing power generation capacity, which existing methods struggle to address effectively without compromising photoelectric conversion efficiency.
Innovation Solution
A manufacturing method involving atomic layer deposition to form dense silicon oxide layers on the front and back sides of a silicon wafer, with specific thicknesses and refractive indices, to block alkali metal ion migration and maintain reflection reduction effects, enhancing PID resistance and photoelectric conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a reflection reduction film is used to improve light absorption, then photoelectric conversion efficiency is improved, but alkali metal ions can migrate through the film causing PID degradation
Solution Approach 1:
The reflection reduction film is divided into multiple sub-layers with different functions: the first silicon nitride layer (101) and second silicon nitride layer (102) provide passivation and block alkali metal ions, while the third silicon oxide layer (110) provides additional passivation and the outer silicon oxide layer (201) maintains reflection reduction. This segmentation allows each layer to specialize in one function, resolving the contradiction between maintaining reflection reduction properties and blocking ion migration.
Solution Approach 2:
The first silicon oxide layer (202) formed by atomic layer deposition acts as an intermediary barrier between the silicon wafer and the external environment. This thin dense oxide layer specifically blocks alkali metal ions while being thin enough not to interfere with the optical properties of the reflection reduction film, thus resolving the contradiction between ion blocking and light absorption.
2Device complexity
If the reflection reduction film structure is simplified to reduce manufacturing complexity, then manufacturing cost is reduced, but PID resistance deteriorates
Solution Approach 1:
A thin dense silicon oxide layer (202) is formed on the silicon wafer surface before depositing the reflection reduction film layers. This preliminary action creates a foundation that blocks alkali metal ions from reaching the silicon wafer, ensuring PID resistance is built into the structure from the beginning rather than requiring complex post-processing or overly complicated multi-layer designs.
Solution Approach 2:
The patent uses a composite structure combining silicon nitride layers (for passivation and ion blocking) with silicon oxide layers (for passivation and reflection reduction). This composite material approach achieves both PID resistance and optical performance without requiring excessive structural complexity, as each material contributes its specific properties to the overall system.
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 method effectively blocks alkali metal ion migration, improving PID resistance and maintaining high photoelectric conversion efficiency by ensuring good short-wave response and absorption, leading to increased short-circuit current and open-circuit voltage.
Implementation Method 1
forming a first silicon oxide layer and a second silicon oxide layer respectively on a front side and a back side of the semi-finished silicon wafer through an atomic layer deposition process
Implementation Method 2
the gaseous silicon-based precursor is adsorbed onto a surface of the semi-finished silicon wafer
Implementation Method 3
a reaction of the gaseous oxidant precursor and the gaseous silicon-based precursor adsorbed onto the surface of the semi-finished silicon wafer is performed
Data Source
AI summary
In one aspect, a manufacturing method for a solar cell includes: providing a semi-finished silicon wafer, and forming a first silicon oxide layer and a second silicon oxide layer respectively on a front side and a back side of the semi-finished silicon wafer through an atomic layer deposition process. The semi-finished silicon wafer includes at least one back silicon nitride layer, an aluminum oxide layer, a silicon layer, at least one front silicon nitride layer, a silicon oxynitride layer, and a third silicon oxide layer arranged in sequence along a thickness direction thereof. The first silicon oxide layer is bound to a surface of the third silicon oxide layer, and the second silicon oxide layer is bound to a surface of the back silicon nitride layer.