Solar Cell Finger Electrode Insulating Coating EVA Hydrolysis
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Solution Overview
Problem
The use of EVA as a filler in solar battery modules leads to a significant decrease in photoelectric conversion efficiency over time due to moisture permeation and hydrolysis, which affects the electrodes and reduces bonding strength.
Innovation Solution
A backside contact solar battery cell with finger electrodes made of silver and glass, where at least the surface of the finger electrodes is covered with an insulating material that does not hydrolyze or generate carboxylic acid, such as silicone or polyimide resin, to prevent direct contact with EVA and maintain photoelectric conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If EVA is used as filler in solar battery modules, then initial photoelectric conversion efficiency is achieved, but photoelectric conversion efficiency decreases significantly over time due to hydrolysis and moisture permeation
Solution Approach 1:
A resin layer is introduced as an intermediary barrier between the finger electrode and the EVA filler. This resin layer prevents direct contact between the electrode and hydrolyzing EVA, thereby blocking the harmful effects of acetic acid and moisture while maintaining the module's initial photoelectric conversion efficiency and stability over time.
Solution Approach 2:
A thin resin film is applied to cover the finger electrode surface. This flexible thin film serves as a protective barrier that prevents moisture and acetic acid from reaching the electrode, thus maintaining long-term reliability without compromising the module's structural integrity or initial performance.
2Strength
If finger electrodes are exposed to EVA filler, then initial bonding is achieved, but bonding strength decreases over time due to hydrolysis
Solution Approach 1:
The resin layer acts as a protective intermediary between the finger electrode and EVA filler, maintaining stable bonding strength over time by preventing hydrolysis and acetic acid corrosion while preserving the initial bonding characteristics.
3Ease of manufacture
If conventional electrode structures are used, then manufacturing simplicity is maintained, but degradation from EVA hydrolysis cannot be prevented
Solution Approach 1:
A thin resin film is applied to the finger electrode surface using conventional coating or lamination techniques. This approach provides protection against EVA hydrolysis while maintaining manufacturing simplicity and compatibility with existing production processes.
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 solution effectively maintains high photoelectric conversion efficiency over time by preventing degradation caused by EVA hydrolysis and enhances mechanical strength, reducing downtime in module manufacturing and improving initial characteristics.
Implementation Method 1
the material containing an insulating material does not hydrolyze or does not generate a carboxylic acid when it hydrolyzes
Implementation Method 2
the material containing an insulating material further contains conductive particles
Implementation Method 3
the finger electrode includes silver and glass
Data Source
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AI summary
The present invention provides a solar battery cell including a finger electrode on a first main surface of a semiconductor substrate, the solar battery cell being characterized in that at least a surface of the finger electrode is covered with a material containing an insulating material so that the surface is not exposed, and the material containing the insulating material does not hydrolyze or does not generate a carboxylic acid when it hydrolyzes. Consequently, it is possible to provide a solar battery cell which suppresses a reduction in photoelectric conversion efficiency with time even though EVA is used and to provide a photovoltaic module using this solar battery cell.