Textured Solar Cell Passivation for Laser-Cut Edge Defect Control
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Solution Overview
Problem
Conventional solar cells face efficiency losses due to carrier recombination at cut edges and internal losses in photovoltaic modules, particularly when using laser cutting methods, which create dangling bonds and defect states, leading to reduced efficiency and increased leakage currents.
Innovation Solution
The solar cell design incorporates a textured structure on the substrate with a doped conducting layer, a first passivation layer covering the textured surface, and a second passivation layer on the contact layer, which reduces carrier recombination and enhances light absorption, thereby improving efficiency and preventing leakage currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If laser cutting method is used to manufacture solar cells, then productivity is improved, but manufacturing precision deteriorates due to created dangling bonds and defect states
Solution Approach 1:
The patent applies preliminary action by forming passivation layers (first passivation layer on front surface, second passivation layer on back surface) before the laser cutting process. These passivation layers are deposited in advance to protect the silicon substrate from damage during subsequent cutting, preventing the formation of dangling bonds and defect states at the cut edges.
Solution Approach 2:
The patent implements beforehand cushioning by introducing protective passivation structures that cushion and absorb the thermal and mechanical stress generated during laser cutting. The passivation layers act as a buffer between the laser energy and the silicon substrate, reducing the harmful effects of rapid heating and cooling that would otherwise create defects.
2Device complexity
If conventional solar cell structure is used, then device complexity is reduced, but reliability deteriorates due to carrier recombination at surfaces and cut edges
Solution Approach 1:
The patent applies segmentation by dividing the surface passivation into distinct functional segments: a first passivation layer for the front surface (light-receiving side) and a second passivation layer for the back surface (contact side). Each segment is optimized for its specific function, with the front surface passivation minimizing light reflection and recombination, while the back surface passivation provides electrical contact and passivation.
Solution Approach 2:
The patent implements local quality by providing different passivation characteristics at different locations of the solar cell. The front surface receives a passivation layer optimized for optical performance and carrier passivation, while the back surface receives a passivation layer optimized for electrical contact. The cut edges also receive specialized passivation treatment to address their specific recombination issues.
3Reliability
If passivation layers are added to reduce carrier recombination, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by designing passivation layers that perform multiple functions simultaneously. The first passivation layer on the front surface provides both optical function (reducing reflection) and electrical function (passivating carriers). The second passivation layer on the back surface provides both electrical contact function and passivation function. This multi-functionality reduces the need for separate specialized layers, thereby limiting the increase in device complexity.
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 enhances the passivation effect on the solar cell surfaces, increases photogenerated current, and improves the overall conversion efficiency while reducing reverse currents and internal losses.
Implementation Method 1
At least the first surface and a portion of the first side surface of the substrate include a textured structure
Implementation Method 2
The doped conducting layer is disposed at least on the first surface and the portion of the first side surface to cover the textured structure
Implementation Method 3
The first passivation layer is stacked on the doped conducting layer and covers the first surface and at least the portion of the first side surface, so as to cover at least the doped conducting layer
Data Source
AI summary
The present application relates to a method for manufacturing a solar cell. In the method, a wafer including a substrate and a doped conducting layer is provided. A doped conducting layer is disposed at least on the first surface and the portion of the first side surface, thereby covering the textured structure. A passivating contact layer is formed on the second surface of the substrate. A first passivation layer is formed on the doped conducting layer. The first passivation layer covers the first surface and at least the portion of the first side surface, thereby covering at least the doped conducting layer. A second passivation layer is formed on the passivating contact layer. The second passivation layer covers the second surface, thereby covering the passivating contact layer.