Quarter-Cell Photovoltaic Module Circuit for Lower String Loss
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Solution Overview
Problem
Photovoltaic modules experience high current in a single cell string and significant overall power loss due to the increasing size of solar cells, leading to decreased overall power output.
Innovation Solution
The photovoltaic module is designed with three cell string groups connected in series, each comprising four cell strings connected in parallel, where each cell is a quarter cell cut from a whole cell, with specific dimensions to ensure creep distance compliance and normal operation, and includes busbars and lead wires for electrical connections, along with bypass diodes for fault protection and insulation layers to prevent short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the size of solar cells is increased to improve output power, then the power of photovoltaic modules increases, but the current in a single cell string becomes high resulting in significant overall power loss
Solution Approach 1:
The solar cell is divided into quarter cells (cutting the whole cell into four parts) to reduce the current in each cell string. This segmentation allows the use of larger cell areas for higher power output while maintaining lower current levels through the parallel string configuration, thereby reducing overall power loss.
Solution Approach 2:
Multiple cell strings are connected in parallel within each cell string group (four strings per group) to combine their current output. This merging approach allows the module to achieve high power output through increased voltage from series-connected groups while keeping individual string currents low, thus reducing resistive power losses.
2Loss of energy
If quarter cells are used to reduce current in cell strings, then power loss is reduced, but the overall output current increases due to the use of cut cells
Solution Approach 1:
The cell is segmented into quarters and arranged in parallel strings, which reduces the current in each individual string while maintaining the overall power output through the combined effect of multiple strings connected in series-parallel configuration.
Solution Approach 2:
The patent transitions from a single-cell-string configuration to a multi-dimensional array structure with three groups of parallel cell strings. This dimensional expansion allows the system to optimize current distribution across multiple parallel paths while maintaining high voltage through series connection of groups.
3Loss of energy
If the cell width is reduced to create quarter cells, then the current circuit length is shortened, but the string length may not meet the creep distance requirement
Solution Approach 1:
The cell is divided into quarter cells with optimized dimensions (width L2 between 46.675mm and 53.25mm) that shorten the current circuit length to reduce internal power loss while the series connection of multiple cells in each string maintains the required string length for creep distance compliance.
Solution Approach 2:
The cell dimensions are specifically optimized with width L2 in the range of 46.675mm to 53.25mm to achieve the right balance between shortening current path length (reducing power loss) and maintaining sufficient string length when multiple cells are connected in series to meet creep distance requirements.
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 reduces the current in a single cell string by half, lowers power loss by 3/4, increases overall power output by at least 5 watts, and ensures safe and stable operation by preventing short circuits and hot spot effects.
Implementation Method 1
photovoltaic module includes three cell string groups connected in series, and each of the three cell string groups includes four cell strings connected in parallel; the cell string includes cells electrically connected
Data Source
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AI summary
The present disclosure provides a photovoltaic module. The photovoltaic module includes three cell string groups (11, 12, 13) connected in series, the three cell string groups each include four cell strings (14) in parallel. The cell string (14) includes multiple electrically connected cells (15), which are quarter cells cut from the whole cell. Among them, the length L1 of the cell is 182.3mm, and the width L2 of the cell satisfies 46.675mm < L2 < 53.25mm. The photovoltaic module adopts a four in four circuit design, which means that the cells (15) are quarter cells cut from the whole cell, and each cell string group (11-13) includes four parallel cell strings (14). This not only reduces the current in a single cell string and lowers the power loss of a single cell string, but also avoids the overall output current of the photovoltaic module caused by the use of cut cells. This ensures that the overall output current of the photovoltaic module in this embodiment is equal to that of the conventional photovoltaic module using two-piece cells, ensuring the overall power of the photovoltaic module in the present disclosure.