Flexible Solar Cell Connectors for Low-Stress String Assembly
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Solution Overview
Problem
Existing solar cell strings face challenges with rigid cell connectors that lead to increased contact resistance, mechanical stress, and potential cell fracture due to thermal loads, requiring a cost-effective and robust solution that reduces the minimum distance between solar cells and improves handling during production.
Innovation Solution
A solar cell string using flexible, slack cell connectors made of metal foils like aluminum, which cover only a small area of the solar cells, allowing for direct electrical connection with high conductivity and reduced shading, enabling closer arrangement of solar cells and increased bending radii, while minimizing material usage and mechanical stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rigid cell connectors are used to electrically connect solar cells, then electrical connection is achieved, but contact resistance increases and mechanical stress leads to cell fracture
Solution Approach 1:
The patent replaces rigid cell connectors with a flexible cell connector comprising a thin conductive foil (thickness 5-50 μm). This flexible connector can deform to accommodate thermal expansion and mechanical stresses without transmitting excessive forces to the solar cells, thereby preventing cell fracture while maintaining electrical conductivity. The flexible nature allows the connector to absorb mechanical loads through elastic deformation rather than rigid force transmission.
Solution Approach 2:
The patent changes the physical parameters of the cell connector by using a thin foil structure with high electrical conductivity rather than a thick rigid connector. The reduced thickness (5-50 μm) and increased flexibility fundamentally alter the mechanical and electrical properties, enabling the connector to maintain low contact resistance while resisting mechanical stress-induced failures.
2Strength
If thick cell connectors are used to ensure mechanical stability, then handling during production is difficult and minimum distance between cells increases
Solution Approach 1:
The flexible thin foil connector (5-50 μm thickness) provides sufficient mechanical stability for handling during production while being thin enough to allow close spacing between solar cells. The flexibility compensates for the reduced thickness, enabling the connector to maintain structural integrity during handling without requiring excessive thickness that would increase cell spacing requirements.
Solution Approach 2:
The patent transitions from rigid three-dimensional connectors to thin two-dimensional foil structures. This dimensional reduction allows the connectors to be laid flat between cells, minimizing the distance required between adjacent solar cells and enabling higher cell density in the module while maintaining adequate mechanical stability for production handling.
3Reliability
If cell connectors cover large area of solar cells, then electrical connection is improved, but shading of incident electromagnetic radiation increases
Solution Approach 1:
The thin conductive foil connector minimizes the coverage area on the solar cell surfaces while maintaining electrical connectivity. The reduced width of the connector (covering region width < 1000 μm, preferably < 500 μm) decreases the shading effect on incident light, allowing more electromagnetic radiation to reach the active areas of the solar cells for energy conversion.
Solution Approach 2:
The patent applies the cell connector only in the specific local regions where electrical connection is required (at the edges of solar cells), rather than covering large areas. This localized application ensures adequate electrical contact while minimizing the impact on light absorption in the active cell areas, optimizing both electrical and optical performance.
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 flexible connectors reduce contact resistance, enhance mechanical stability, and allow for more compact solar cell arrangements, improving production efficiency and reducing material costs while maintaining high electrical quality and fault tolerance.
Implementation Method 1
the cell connector is a flexurally slack cell connector, that the cell connector at least partly covers a side of the solar cell A and the electrode A in a cell connector covering region A
Implementation Method 2
the electrode A being electrically conductively connected to the electrode B by means of a cell connector of the solar cell string
Data Source
AI summary
A solar cell string, includes a first photovoltaic solar cell A and at least one second photovoltaic solar cell B, the solar cell A having at least one metallic electrode A and the solar cell B having at least one metallic electrode B, the electrode A being electrically conductively connected to the electrode B by a cell connector of the solar cell string. The cell connector is a flexurally slack cell connector, at least partly covering a side of the solar cell A and the electrode A in a cell connector covering region A, the connector is at least partly directly electrically conductively connected to the electrode A in the connector covering region A. The cell connector is at least partly directly electrically conductively connected to the electrode B in the cell connector covering region B, and the cell connector covering region A or the cell connector covering region B.