Photovoltaic Module Bus Bar Layout for Higher Cell Area
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Solution Overview
Problem
The layout of bus bars in photovoltaic modules occupies space in the length direction, reducing the area proportion of cells and affecting efficiency.
Innovation Solution
The bus bar is positioned at the back surface of the cells, with a solder strip connecting the cell to the bus bar, and the solder strip has a bending section that is misaligned with the connecting section, reducing the space occupied by the bus bar in the length direction and minimizing overlap with the cell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bus bar is arranged at two opposite sides of the cell string along the length direction, then the bus bar can effectively connect the cells, but the bus bar occupies space in the length direction, reducing the area proportion of the cell
Solution Approach 1:
The bus bar is moved from the length direction to the thickness direction, changing its spatial arrangement from lateral placement to vertical placement. This dimensional transition allows the bus bar to be positioned at the back surface of the cell, eliminating its occupation of cell area in the length direction while maintaining electrical connection functionality through the solder strip.
Solution Approach 2:
The bus bar is nested within the projection of the cell string along the thickness direction, with at least part of the bus bar's projection overlapping with the cell string's projection. This nesting arrangement allows the bus bar to be spatially integrated with the cell structure, minimizing its impact on the cell's effective area while ensuring proper electrical connection.
2Device complexity
If the solder strip connects the cell to the bus bar with a straight configuration, then the connection is simple, but the bending section misalignment is required to reduce stress concentration and hidden cracks
Solution Approach 1:
The solder strip incorporates a bending section with a non-parallel extension direction relative to the connecting section, creating a curved or angled configuration. This curvature in the solder strip path reduces stress concentration and minimizes the risk of hidden cracks during lamination, improving connection reliability despite increased structural complexity.
Solution Approach 2:
The solder strip's geometric parameters are modified by introducing a bending section with specific angular deviations (5° to 25° angle between extension directions). This parameter change optimizes the stress distribution in the solder strip, reducing stress concentration at connection points and enhancing the overall reliability of the electrical connection.
Data Source
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AI summary
The present disclosure relates to a photovoltaic module. The photovoltaic module includes a cell string, a bus bar, and at least one solder strip configured to connect the bus bar to a cell of the cell string. Along a thickness direction of the photovoltaic module, the bus bar is located at a side where a back surface of the cell is located, and at least part of a projection of the bus bar along the thickness direction Z of the photovoltaic module is located within a projection range of the cell string along the thickness direction Z of the photovoltaic module. The solder strip includes a connecting section and a bending section, the connecting section is connected to the cell, the bending section bends towards the side where the back surface of the cell is located and is connected to the bus bar, and an extension direction of the bending section is not parallel to an extension direction of the connecting section. Through this design, the bus bar is arranged on a back side of the cell, which reduces a space occupied by the bus bar in a length direction of the photovoltaic module, thereby helping to improve an area proportion of the cell and helping to improve efficiency of the photovoltaic module