Solar Cell Electrode Composition to Prevent Backside Short-Circuiting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing solar cell structure is prone to defects due to metal particles from the back electrode penetrating the passivation layer and short-circuiting with the semiconductor substrate, which affects the open-circuit voltage (Voc) and efficiency.
Innovation Solution
A solar cell design with a second electrode containing a lower glass frit content and a specific metal particle distribution, where the glass frit includes PbO-based or BiO-based materials and tellurium oxide, is used to control the firing depth and prevent short-circuiting, while the first electrode has a higher glass frit and metal particle content to enhance conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a back electrode with high metal particle content is used to improve conductivity, then electrical conductivity is improved, but metal particles penetrate the passivation layer and cause short-circuiting with the semiconductor substrate
Solution Approach 1:
The patent changes the chemical composition parameters of the electrode material by incorporating glass frit (containing PbO, BiO, or TeO) into the metal particle matrix. This modifies the melting behavior and penetration characteristics of the electrode, allowing it to achieve adequate conductivity while preventing harmful short-circuiting through controlled chemical interaction with the passivation layer.
Solution Approach 2:
The patent creates a composite electrode material consisting of metal particles (for conductivity) combined with glass frit components (for penetration control). This composite structure enables the electrode to simultaneously achieve electrical conductivity and controlled interaction with the passivation layer, preventing metal particle penetration that would cause short-circuits.
2Object-affected harmful factors
If glass frit content in the second electrode is increased to prevent short-circuiting, then penetration is reduced, but contact resistance increases and conductivity decreases
Solution Approach 1:
The patent optimizes the glass frit content parameter within a specific range (2.5-5.0 wt%) to achieve the desired balance. This parameter optimization ensures sufficient penetration prevention while maintaining adequate electrical contact, resolving the contradiction between protection and conductivity.
3Reliability
If the thickness of the conductive region is reduced to improve open-circuit voltage, then Voc is improved, but the back electrode short-circuits with the semiconductor substrate through the thinner passivation layer
Solution Approach 1:
The patent modifies the chemical composition parameters of the electrode material (adding glass frit with specific oxides) to change its interaction characteristics with the passivation layer. This allows the electrode to work effectively with reduced passivation layer thickness while preventing short-circuits, enabling both improved Voc and defect prevention.
Solution Approach 2:
The glass frit acts as an intermediary substance between the metal particles and the passivation layer. It mediates the interaction by providing controlled chemical interaction that prevents direct metal penetration through the thin passivation layer, allowing the system to achieve both thin-layer benefits and protection against short-circuiting.
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 effectively prevents short-circuiting and improves the open-circuit voltage (Voc) by maintaining a low contact resistance and adequate passivation function, thereby enhancing the solar cell's performance and reducing manufacturing defects.
Implementation Method 1
a content of the glass frit per unit volume contained in the second electrode is less than a content of the glass frit per unit volume contained in the first electrode
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A solar cell is disclosed. The solar cell includes a first conductive region positioned at a front surface of a semiconductor substrate and containing impurities of a first conductivity type or a second conductivity type, a second conductive region positioned at a back surface of the semiconductor substrate and containing impurities of a conductivity type opposite a conductivity type of impurities of the first conductive region, a first electrode positioned on the front surface of the semiconductor substrate and connected to the first conductive region, and a second electrode positioned on the back surface of the semiconductor substrate and connected to the second conductive region. Each of the first and second electrodes includes metal particles and a glass frit.