PV Ribbon Pre-Fixing on Solar Cell Gridlines for Reliable Soldering
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Solution Overview
Problem
The existing methods for fixing PV ribbons in photovoltaic modules, such as using adhesive tape or adhesive film, are inadequate, leading to potential offset and reduced soldering quality due to decreased tape stickiness in high-temperature environments or increased production difficulty.
Innovation Solution
A photovoltaic module design that includes an insulating layer covering the gridline with conductive adhesives on the gridline, allowing the PV ribbon to be pre-fixed through the conductive adhesive, preventing displacement and improving soldering reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adhesive tape is used to fix the PV ribbon, then the PV ribbon can be fixed before soldering, but the tape stickiness decreases in high-temperature environment during soldering, causing offset of the PV ribbon
Solution Approach 1:
The patent introduces an insulating layer as an intermediary substance between the PV ribbon and the solar cell surface. This insulating layer serves multiple functions: it provides stable adhesion during high-temperature soldering without the stickiness degradation problem of adhesive tapes, prevents short circuits by isolating the PV ribbon from conductive gridlines, and maintains positioning accuracy throughout the soldering process. The insulating layer effectively mediates between the conflicting requirements of thermal stability and electrical isolation.
Solution Approach 2:
The patent changes the material parameters of the fixing layer by using insulating layer material with specific properties: high-temperature resistance to maintain adhesion strength during soldering, appropriate thickness (0.5-5μm) to balance fixation and laser beam transmission, and electrical insulation properties to prevent short circuits. These parameter changes resolve the contradiction between maintaining fixing reliability at high temperatures and preventing electrical shorts.
2Reliability
If press mesh is provided on the PV ribbon to pre-fix the PV ribbon in infrared soldering, then the PV ribbon can be fixed, but the press mesh may block the laser beam and affect the soldering quality in laser soldering process
Solution Approach 1:
The insulating layer acts as an intermediary that replaces the press mesh functionality while being transparent to laser beams. Unlike the press mesh that physically blocks laser radiation, the insulating layer provides the same fixation function through adhesion and dimensional stability, allowing the laser beam to pass through unaffected and achieve proper soldering quality.
Solution Approach 2:
The patent replaces the mechanical press mesh system with a chemical/adhesive-based insulating layer system. The press mesh relies on mechanical pressure and physical blocking, which interferes with laser soldering. The insulating layer uses adhesive bonding and material properties to achieve fixation without mechanical intervention, eliminating the laser beam blocking issue while maintaining fixing reliability.
3Reliability
If the insulating layer covers the entire gridline, then short circuit is prevented, but the current collection area is reduced
Solution Approach 1:
The patent applies local quality by making the insulating layer selectively transparent only at the solder pad locations while maintaining coverage over the gridline in other areas. This localized approach allows current collection at the solder pads where it is needed, while providing electrical isolation over the gridline where short circuits would occur. The insulating layer thus has different functional properties in different locations, resolving the contradiction between isolation and current collection.
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 design enhances soldering tension, reduces power loss and heat accumulation, and improves conductive efficiency by shortening the current path without additional solder pads, while maintaining high reliability.
Implementation Method 1
the conductive adhesive adheres to the PV ribbon, to pre-connect adjacent cell bodies through the PV ribbon
Implementation Method 2
the solder pad and the conductive adhesive are respectively provided on the gridline and are electrically connected to the gridline
Implementation Method 3
the insulating layer covers the gridline and exposes the solder pad and the conductive adhesive
Data Source
Figure 1~2
Figure 3
Figure 4(a)~4(e)
AI summary
The present invention relates to a photovoltaic module and a manufacturing method thereof. The photovoltaic module includes a plurality of solar cells and a plurality of PV ribbons configured to connect the plurality of solar cells; each solar cell includes a cell body, a gridline, a solder pad, an insulating layer, and a conductive adhesive, the gridline is provided on a surface of the cell body, the solder pad and the conductive adhesive are respectively provided on the gridline and are electrically connected to the gridline, the insulating layer covers the gridline and exposes the solder pad and the conductive adhesive, the solder pad and the conductive adhesive are respectively connected to the PV ribbon. By providing the conductive adhesive on the gridline, when the PV ribbon is soldered, the PV ribbon is pre-fixed through the conductive adhesive.