Photovoltaic Junction Box Heat Dissipation via Air Channels
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Solution Overview
Problem
Photovoltaic junction boxes face challenges in effectively dissipating heat generated by bridging diodes at higher currents, which can lead to thermal runaway and module failure, especially when shaded cells create bottlenecks and generate excessive heat, potentially causing fires.
Innovation Solution
The junction box design incorporates heat dissipating components such as elongated fins and outwardly extending fingers on its housing and conductor plate, along with air channels created by gaps between the housing and mounting flange, to enhance heat dissipation through convection and thermal conductivity, using an electrically insulating material to manage temperature effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bridging diodes are used to prevent catastrophic failure from shaded cells, then reliability is improved, but heat generation increases causing thermal runaway risk
Solution Approach 1:
The patent introduces a third dimension for heat dissipation by extending heat dissipating fins outward from the housing sides, moving heat management from internal conduction only to a combination of conduction and external convection surfaces, thereby increasing heat dissipation capacity without adding internal complexity
Solution Approach 2:
The heat dissipating fins act as an intermediary between the heat-emitting diodes and the ambient environment, providing an extended thermal interface that facilitates heat transfer from the enclosed junction box interior to the external atmosphere through convection
2Temperature
If heat is conducted from diodes to the module, then heat dissipation is improved, but hot spots are created causing thermal runaway in photovoltaic cells
Solution Approach 1:
The patent extracts the heat dissipation function from the module structure and relocates it to the junction box housing itself, which acts as an independent heat sink with external fins, preventing heat transfer to the photovoltaic cells while still achieving effective temperature management
Solution Approach 2:
The housing, which would normally be a barrier to heat dissipation, is transformed into an active heat dissipation device through the addition of heat dissipating fins, converting the potential harm of heat trapping into a beneficial external convection pathway
3Ease of manufacture
If conventional junction box design is used, then manufacturing simplicity is maintained, but heat dissipation capacity is insufficient for higher currents
Solution Approach 1:
The heat dissipation system is segmented into multiple independent fin structures attached to different sides of the housing, allowing modular manufacturing and assembly while collectively providing sufficient heat dissipation capacity for higher current applications
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 design allows for improved heat dissipation, preventing thermal runaway and ensuring the junction box can handle higher currents while meeting industry standards for temperature management, thus preventing module failure and ensuring safe operation.
Implementation Method 1
heat conducting component corresponding to the heat dissipating component of the housing
Implementation Method 2
The gap creates an air channel that allows air to flow between the housing and the mounting flange
Data Source
AI summary
A photovoltaic junction box that comprises a housing that has at least first and second sides and the second side has at least one heat dissipating component. A conductor plate is received in the housing. The conductor plate supports at least one heat emitting component and at least one heat conducting component corresponding to the heat dissipating component of the housing. A mounting flange extends from the second side of the housing. At least a first gap is located between the second side of the housing and the mounting flange. The gap creates an air channel that allows air to flow between the housing and the mounting flange.