PV Module Busbar Laser Soldering for Reliable Bonding Pads
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Solution Overview
Problem
Existing soldering methods for busbars in photovoltaic modules, such as resistance soldering and electromagnetic soldering, often result in cold solder joints and desoldering due to impurities and uneven heating, affecting the yield of the photovoltaic module.
Innovation Solution
A photovoltaic module design where the busbar is soldered to a bonding pad using laser soldering, with a specific length and depth of the soldering joint relationship (y≥-5x+4.5) to ensure strong adhesion, and multiple joints are arranged with controlled gaps and materials, avoiding excessive soldering and improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If resistance soldering or electromagnetic soldering is used to solder the busbar to the bonding pad, then the soldering process can be completed, but cold solder joints and desoldering occur due to impurities and uneven heating, reducing reliability
Solution Approach 1:
The patent replaces traditional resistance soldering or electromagnetic soldering methods with laser soldering. The laser soldering head directs laser beams to melt the soldering wire and bonding pad material, forming soldering joints through controlled melting and solidification rather than through resistance heating or electromagnetic induction, thereby eliminating the harmful effects of uneven heating and impurities
Solution Approach 2:
The patent controls the soldering joint parameters including extension depth into the bonding pad (0.3-0.8mm) and length along the busbar (1.0-3.0mm), satisfying the relationship y≥-5x+4.5. These parameter optimizations ensure adequate bonding strength while preventing excessive penetration that could cause defects, directly addressing the reliability issues
2Productivity
If traditional soldering methods are used, then the busbar can be connected to the bonding pad, but the soldering quality is affected by impurities and uneven heating, reducing manufacturing yield
Solution Approach 1:
The patent replaces traditional soldering methods with laser soldering, where a laser soldering head directs laser beams to precisely melt and fuse the bonding pad material with the busbar. This optical-based method eliminates the impurities and uneven heating associated with resistance or electromagnetic soldering, significantly improving both soldering quality and manufacturing yield
Solution Approach 2:
The patent introduces a laser soldering head as an intermediary device that delivers controlled laser energy to the bonding pad and busbar interface. The laser beam acts as a precise energy mediator, melting materials uniformly and forming high-quality soldering joints without introducing contaminants, thereby improving manufacturing precision and yield
3Strength
If the soldering joint extends deeply into the bonding pad, then adhesion strength increases, but excessive penetration may cause defects and reduce reliability
Solution Approach 1:
The patent optimizes the soldering joint parameters by controlling the extension depth into the bonding pad to be 0.3-0.8mm and the length along the busbar to be 1.0-3.0mm. The relationship y≥-5x+4.5 ensures adequate bonding strength while preventing excessive penetration that could cause defects such as through-holes or material displacement, thereby maintaining high reliability
Solution Approach 2:
The patent applies controlled partial melting through laser soldering, where the laser beam melts the bonding pad material to a controlled depth rather than completely melting through. This partial action creates sufficient adhesion strength while avoiding the harmful effects of excessive penetration, achieving the optimal balance between strength and reliability
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 laser soldering method enhances the soldering strength and reliability between the busbar and bonding pad, reducing cold solder joints and desoldering issues, thereby improving the process yield and efficiency of the photovoltaic module.
Implementation Method 1
the busbar and the bonding pad are soldered together by laser soldering
Implementation Method 2
The soldering joint penetrates through one end of the busbar, and extends into the bonding pad
Data Source
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AI summary
The present application belongs to the technical field of photovoltaic modules, and specifically discloses a photovoltaic module. The photovoltaic module includes: a junction box, including a bonding pad; and a busbar, one end of the busbar being attached to a surface of the bonding pad and soldered to the bonding pad through at least one soldering joint, where the soldering joint penetrates through one end of the busbar, and extends into the bonding pad, the extension depth of the soldering joint in the bonding pad is x, the length of the soldering joint is y, y is greater than or equal to -5x+4.5, and the unit of both x and y is mm.