Solar Module Junction Box with Parallel Overvoltage Protection
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Solution Overview
Problem
Conventional solar panels face issues with reduced operational reliability due to voltage peaks caused by induced currents and line inductances, which can lead to damage or destruction of solar cells and bypass diodes, especially during thunderstorms or disconnection events.
Innovation Solution
A junction box design incorporating printed circuit board contact devices with integrated bypass diodes and overvoltage protection elements, where the overvoltage protection elements are connected in parallel with the bypass diodes to respond faster to voltage spikes, preventing damage and ensuring continuous operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bypass diodes are used to protect solar cell groups from partial shading effects, then the reliability of solar module operation is improved, but the bypass diodes are vulnerable to damage from voltage peaks caused by induced currents and line inductances
Solution Approach 1:
The patent introduces overvoltage protection elements (such as varistors or suppressor diodes) that are pre-installed in parallel with the bypass diodes to cushion against voltage peaks before they can damage the bypass diodes. These protection elements activate beforehand when voltage thresholds are exceeded, absorbing or diverting the harmful voltage spikes caused by induced currents and line inductances during thunderstorms or disconnection events.
2Device complexity
If conventional bypass diodes are used without overvoltage protection, then the structure remains simple, but the service life of the solar panel is reduced due to vulnerability to voltage peaks
Solution Approach 1:
The patent merges the bypass diode function with overvoltage protection by connecting these two elements in parallel within the same junction box circuit. This combination allows the system to maintain the simple overall structure while integrating additional protection functionality. The bypass diode continues its primary function of redirecting current around shaded solar cell groups, while the parallel-connected overvoltage protection elements simultaneously protect against voltage peaks, thereby extending the service life without significantly increasing structural complexity.
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 operational reliability by protecting bypass diodes from overvoltages, preventing damage and ensuring uninterrupted current flow, thus extending the lifespan of solar panels.
Implementation Method 1
the response time of the at least one overvoltage protection element is shorter than the response time of the bypass diodes in order to protect the at least one bypass diode from overvoltages
Implementation Method 2
the connections of this group of solar cells of a solar module are short-circuited by the bypass diode and the corresponding group of solar cells is thereby bypassed
Implementation Method 3
Conventional solar modules for generating electrical energy from sunlight comprise one or more individual solar cells
Data Source
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AI summary
The socket (7) has electrically-conducting contact devices (13a-13d) that are connected with respective electrical conductors (5a-5d) of a solar module (3), where two of the contact devices are designed as printed circuit boards and comprise over-voltage short-circuit areas (28a-28c). Bypass-diodes (25a-25c) are provided for electrically connecting the contact devices, and over-voltage protection elements (27a-27c) e.g. suppressor-diode or Zener-diode, are connected parallel to the respective bypass-diodes, where each contact device is made from an even metal plate.