Photovoltaic Junction Box Laser Welding for Stable Current Output
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Solution Overview
Problem
The reliability of electrical connections between wiring members and bonding pads in photovoltaic modules is poor, leading to instability and low efficiency in the output of photo-generated current due to differences in metal materials and temperature expansion, as well as issues with cold joints and delamination.
Innovation Solution
A photovoltaic module design that uses laser welding to form weld seams between the wiring member and the bonding pad, creating an integrated structure without the need for metal tin, ensuring a strong and reliable connection by melting and integrating the metal materials, and optionally using a thin tin layer to prevent oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional metal material connections are used between wiring member and bonding pad, then the connection process is simple, but the connection reliability is poor due to temperature expansion differences and cold joints
Solution Approach 1:
The patent changes the connection method from traditional mechanical or solder-based joining to laser welding, fundamentally altering the physical and chemical parameters of the connection process. This enables direct metal-to-metal bonding with controlled penetration depth (not greater than 80% of bonding pad thickness), achieving reliable electrical connection while avoiding cold joints and delamination issues associated with traditional methods
Solution Approach 2:
The patent replaces traditional mechanical connection methods (screws, clips, or soldering) with laser welding technology. The laser beam provides precise thermal energy to create metallurgical bonds between the wiring member and bonding pad, eliminating the need for mechanical fasteners or solder intermediaries, thereby improving connection reliability while maintaining process simplicity
2Reliability
If laser welding is used to form weld seams between wiring member and bonding pad, then the connection reliability is improved, but the manufacturing precision requirement increases
Solution Approach 1:
The patent applies local quality by creating weld seams with specific characteristics at the bonding interface: the weld seams are confined to localized regions where the wiring member contacts the bonding pad, with controlled penetration depth (not greater than 80% of bonding pad thickness). This localized welding approach ensures reliable electrical connection at the critical interface while minimizing thermal affect zones and maintaining precision requirements manageable through focused energy application
3Strength
If deep weld seams are formed in the bonding pad, then the connection strength is improved, but the bonding pad integrity is compromised
Solution Approach 1:
The patent applies partial action by controlling the weld seam penetration depth to be not greater than 80% of the bonding pad thickness. This partial penetration provides sufficient connection strength for reliable electrical bonding while deliberately leaving the bottom 20% of the bonding pad intact, preserving the structural integrity and electrical conductivity of the bonding pad substrate. The controlled partial weld avoids through-hole formation that would compromise bonding pad stability
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 enhances the connection reliability and efficiency of photo-generated current output by forming a strong, stable interface between the wiring member and the bonding pad, resistant to temperature changes and oxidation, thereby improving the overall performance of the photovoltaic module.
Implementation Method 1
the wiring member is connected with the bonding pad by a plurality of weld seams formed by laser welding
Implementation Method 2
creating an integrated structure without the need for metal tin, ensuring a strong and reliable connection by melting and integrating the metal materials
Implementation Method 3
optionally using a thin tin layer to prevent oxidation
Data Source
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AI summary
Embodiments of the present disclosure relates to a photovoltaic module and a method for producing the photovoltaic module. The photovoltaic module includes a photovoltaic laminate and a junction box. The junction box is fixed and connected to a side of the rear plate away from the plurality of solar cells, and the junction box includes a bonding pad. The wiring member passes through an opening defined on the rear plate and abuts the bonding pad, and the wiring member is connected with the bonding pad by a plurality of weld seams formed by laser welding. An extension depth of each of the plurality of weld seams in the bonding pad is not greater than 80% of a thickness of the bonding pad.