Laminated Rear Passivation Structure for P-Type Solar Cells
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Solution Overview
Problem
The existing production methods for laminated passivation structures in solar cells, particularly for P-type monocrystalline silicon solar cells, face challenges in achieving effective passivation while reducing production costs and minimizing hazardous materials usage, such as trimethylaluminum, which is dangerous and costly.
Innovation Solution
A laminated passivation structure comprising a sequence of dielectric layers on the back surface of a P-type silicon substrate, including a first silicon oxide layer, a second dielectric layer with varying refractive indices to enhance light reflection, and a third dielectric layer to reduce surface recombination, utilizing Plasma Enhanced Chemical Vapor Deposition (PECVD) for deposition, and hydrogen diffusion for passivation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If trimethylaluminum (TMA) is used in the deposition process of aluminum oxide film, then the passivation effect is improved, but the production cost increases and safety hazards arise
Solution Approach 1:
The patent replaces expensive and hazardous trimethylaluminum (TMA) with a cheaper, safer alternative deposition process. The new method uses a different chemical approach that eliminates the need for TMA, thereby reducing both production costs and safety risks while maintaining the passivation functionality of the aluminum oxide film.
Solution Approach 2:
The patent changes the deposition parameters and chemical composition used in the aluminum oxide film formation process. By modifying the deposition method to not rely on TMA, the process achieves the same passivation effect with improved cost-effectiveness and safety profile.
2Ease of manufacture
If all-aluminum doping is applied on the back surface to form all-aluminum back field, then the manufacturing process is simplified, but recombination at the metal and silicon contact interface increases and efficiency improvement is limited
Solution Approach 1:
The patent segments the back field structure by introducing a dielectric layer between the aluminum layer and the silicon substrate. This segmentation separates the electrical function (aluminum contact) from the passivation function (dielectric layer), thereby reducing recombination at the interface while maintaining manufacturing simplicity.
Solution Approach 2:
The patent creates a composite structure combining dielectric material and aluminum on the back surface. This composite approach allows the dielectric layer to provide passivation and reduce recombination, while the aluminum layer maintains its electrical functionality, achieving both simplified manufacturing and improved efficiency.
3Reliability
If back passivation film and local aluminum back field technology are introduced, then open-circuit voltage and short-circuit current are improved, but the process complexity increases
Solution Approach 1:
The patent merges the passivation function and the back field formation into a single integrated process step. By combining these functions, the patent achieves improved open-circuit voltage and short-circuit current without proportionally increasing process complexity, as the merged structure performs multiple functions simultaneously.
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 laminated passivation structure achieves improved open-circuit voltage, short-circuit current, and conversion efficiency, with enhanced chemical and bulk passivation effects, reducing production costs and hazards.
Implementation Method 1
utilizing Plasma Enhanced Chemical Vapor Deposition (PECVD) for deposition
Implementation Method 2
hydrogen diffusion for passivation
Implementation Method 3
increasing the long-wave reflection of the back surface
Data Source
AI summary
A laminated passivation structure of solar cell and a preparation method thereof are disclosed herein. The laminated passivation structure of solar cell includes a P-type silicon substrate, a first dielectric layer, a second dielectric layer, and a third dielectric layer sequentially arranged on the back side of the P-type silicon substrate from inside to outside. The preparation method includes generating a first dielectric layer on the back surface of the P-type silicon substrate, and then sequentially depositing a second dielectric layer and a third dielectric layer on the first dielectric layer.