Photovoltaic Junction Box Diode Soldering Configuration
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Solution Overview
Problem
Existing photovoltaic junction boxes suffer from inadequate heat dissipation, leading to overheating and potential damage of diodes, which compromises their bypass function and can cause solar panels to burn due to the hot spot effect.
Innovation Solution
The design incorporates surface mount type diodes with specific soldering configurations, where the area of the soldering bottom surface of the positive pin is larger than that of the negative pin, allowing heat generated by the diodes to be quickly dissipated through the positive wire and negative wire connections, enhancing heat dissipation performance, current carrying capacity, and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the negative pin has a larger soldering bottom surface area than the positive pin, then the diode can be mounted on the terminals, but the heat generated by the diode chip cannot be rapidly dissipated, leading to overheating and diode damage
Solution Approach 1:
The patent inverts the conventional soldering configuration by making the positive pin's soldering bottom surface area larger than the negative pin's. This reversal allows the heat-generating diode chip (connected to the positive pin) to transfer heat more effectively to the positive terminal and subsequently to the positive wire, solving the overheating problem while maintaining proper diode mounting and electrical connectivity.
2Reliability
If the diode chip is directly soldered on the negative pin with larger area, then the diode can be electrically connected to the terminals, but the heat dissipation path is blocked, causing the diode to burn due to overheat
Solution Approach 1:
The patent converts the harmful heat accumulation into beneficial heat dissipation by redesigning the soldering configuration. The larger positive pin soldering area creates an efficient heat transfer path from the diode chip to the positive terminal and wire, transforming the previously harmful overheating condition into an effective thermal management solution that protects against the hot spot effect.
3Ease of manufacture
If the positive pin has smaller soldering area, then the conventional mounting can be used, but the current carrying capacity and heat dissipation performance are insufficient
Solution Approach 1:
The patent changes the critical parameter of soldering bottom surface area distribution, making the positive pin's area larger than the negative pin's. This parameter change simultaneously improves current carrying capacity and heat dissipation performance while remaining compatible with conventional surface mount manufacturing processes, thus achieving enhanced performance without sacrificing manufacturing simplicity.
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 configuration effectively prevents overheating, ensuring the diodes can function as bypasses and maintain the solar panel's integrity by rapidly dissipating heat, thereby improving the photovoltaic junction box's reliability and performance.
Implementation Method 1
the heat generated by the diode chip in use is mostly transferred to the terminal 220' via the negative pin 312'
Data Source
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Figure 5~6
AI summary
A photovoltaic junction box includes: a box body; at least three terminals provided in the box body; and at least two diodes each mounted on adjacent terminals. The at least three terminals comprise a first terminal directly connected to a positive wire entering into the box body and a second terminal adjacent to the first terminal. The at least two diodes comprise a first diode mounted on the first and second terminals, the first diode comprises a chip, a positive pin soldered on the first terminal and a negative pin soldered on the second terminal. An area of a soldering bottom surface of the positive pin of the first diode soldered onto a surface of the first terminal is larger than an area of a soldering bottom surface of the negative pin of the first diode soldered onto a surface of the second terminal. The chip of the first diode is directly electrically connected to the positive pin of the first diode. The heat generated by the first diode may be quickly dissipated out of the box body through the positive wire, improving the heat dissipation performance, the current carrying capacity and the reliability of the photovoltaic junction box.