Solar Module Bypass Diode Integration on Rectifying Sheet
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Solution Overview
Problem
Existing solar modules face challenges in withstanding partial shading conditions without incurring permanent electrical, mechanical, or optical damage, particularly due to high reverse bias voltages that can cause irreversible damage to solar cells, and traditional bypass diodes often result in long electrical paths with high resistance, leading to overheating and increased reverse bias voltage.
Innovation Solution
The integration of bypass diodes within the same rectifying diode sheet as solar cells, connected in an anti-parallel configuration via bus bars, utilizing the higher conductivity of the back electrode layer to reduce electrical resistance and limit reverse bias voltage, eliminating the need for additional processing steps and separate junction boxes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bypass diodes are mounted in a separate junction box, then the module can handle partial shading conditions, but the electrical path becomes long and resistance increases
Solution Approach 1:
The bypass diodes are integrated directly into the rectifying diode sheet on the same substrate as the solar cells, merging the protective function with the power-generating structure. This eliminates the need for separate junction boxes and reduces the electrical path length, thereby decreasing resistance and energy loss while maintaining reliability under shading conditions.
2Device complexity
If bypass diodes are connected through the front surface electrode layer, then the module structure is simplified, but the electrical resistance increases due to the weakly conducting path
Solution Approach 1:
The patent utilizes the back electrode layer which has higher electrical conductivity compared to the front surface electrode layer. By establishing electrical connections through this more conductive back electrode layer, the invention locally optimizes the connection path to reduce resistance and energy loss while maintaining structural simplicity.
3Reliability
If traditional bypass diodes are used, then reverse bias protection is provided, but overheating occurs due to high resistance connections
Solution Approach 1:
The bypass diodes are merged with the solar cell structure on the same rectifying diode sheet, creating integrated protective units. This integration reduces connection resistance and improves heat dissipation, thereby preventing overheating while maintaining reverse bias protection capability under partial shading conditions.
Solution Approach 2:
The invention leverages the higher conductivity of the back electrode layer to create optimized current paths that reduce resistive heating. This local quality improvement in electrical conductivity directly addresses the overheating issue by reducing the thermal load on the bypass diodes during operation.
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 reduces overheating and effectively limits the maximum reverse bias voltage solar cells are exposed to, enhancing the module's durability and efficiency under shading conditions by leveraging the higher conductivity of the back electrode layer for connections.
Implementation Method 1
the back electrode layer has a higher electrical conductivity than the front electrode layer
Implementation Method 2
the maximum reverse bias voltage applied under conditions of partial shading must be limited
Data Source
Figure 1a~1d
Figure 2a~2b
Figure 3a~3b
AI summary
A solar module comprising a common substrate supporting a rectifying diode sheet. The rectifying diode sheet comprising at least a back electrode layer, a front electrode layer, and an absorber layer located between the back electrode layer and the front electrode layer. The rectifying diode sheet is divided in first and second sheet parts, whereby the first sheet part comprises at least one solar cell. The second sheet part comprises at least one bypass diode, circuited in an anti-parallel configuration with the at least one solar cell.