Flexible Photovoltaic Strip Layout for Shading and Ohmic Losses
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Solution Overview
Problem
Existing photovoltaic modules for luminescent solar concentrators face challenges with non-uniform illumination and efficiency loss due to local shading, high ohmic losses from parallel connections, and increased costs from connectors for larger sheets, lacking versatility and efficiency in arbitrary dimensions.
Innovation Solution
A flexible photovoltaic module with a composite strip featuring series-parallel connected photovoltaic cells and a DC-DC conversion circuit, allowing for arbitrary length and size adaptation with minimal connectors and consistent output voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If photovoltaic cells are connected in parallel to increase current generation, then the overall current increases, but ohmic losses due to electrical resistance of interconnections increase
Solution Approach 1:
The photovoltaic array is divided into multiple strings of series-connected cells, and these strings are connected in parallel. This segmentation allows the system to generate higher total current while keeping the current through each individual string lower, thereby reducing ohmic losses in interconnections.
Solution Approach 2:
The invention changes the electrical connection parameters from pure parallel to series-parallel configuration. This parameter change optimizes both current generation and ohmic loss reduction by adjusting the voltage and current distribution across different string configurations.
2Loss of energy
If photovoltaic cells are connected in series to increase potential difference, then ohmic losses decrease, but the current is limited by the less illuminated cell
Solution Approach 1:
The array is segmented into multiple independent strings that are connected in parallel. Each string operates independently, so the current limitation caused by shading affects only one string rather than the entire array, thereby maintaining overall current generation capability.
Solution Approach 2:
The invention changes the connection topology from pure series to series-parallel, which modifies the electrical parameters to balance voltage and current distribution. This allows the system to maintain low ohmic losses while avoiding current limitation by configuring multiple series strings in parallel.
3Reliability
If local shading occurs on the luminescent sheet, then non-uniform illumination of photovoltaic cells occurs, but in series connection this causes loss of overall efficiency
Solution Approach 1:
The photovoltaic array is divided into multiple independent strings. When local shading occurs, only the affected string experiences reduced current, while other strings continue to operate at full capacity. This segmentation isolates the impact of shading and prevents it from limiting the entire array's performance.
Solution Approach 2:
The series-parallel connection configuration changes the electrical parameters such that voltage is maintained across strings while current can vary independently. This parameter change allows the system to maintain efficiency under non-uniform illumination conditions.
4Ease of manufacture
If the length of each photovoltaic array is increased to reduce number of interconnections, then connector cost decreases, but sensitivity to local lighting variations increases
Solution Approach 1:
The array is divided into multiple moderate-length strings connected in parallel. This segmentation reduces the length of each individual string, thereby reducing sensitivity to local lighting variations, while the total number of cells remains the same. The number of connectors is optimized by configuring strings to match available connector types.
Solution Approach 2:
The invention changes the array configuration parameters (string length, number of strings per parallel group) to optimize the balance between connector cost and lighting sensitivity. By adjusting these parameters, the system achieves cost-effective manufacturing without excessive sensitivity to local shading.
5Power
If the luminescent sheet is larger than a single module, then more photovoltaic capacity is needed, but several arrays must be connected by connectors which increase system cost
Solution Approach 1:
The large photovoltaic system is divided into multiple standard-length arrays that can be manufactured and assembled independently. These arrays are then connected in parallel using standard connectors, which reduces the need for custom long arrays and minimizes connector costs through standardization.
Solution Approach 2:
The series-parallel configuration allows the same array design to be scaled to different sizes by simply adding or removing parallel strings. This universal design approach reduces development costs and allows standardized manufacturing processes to be used across different system sizes.
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
Enables efficient, versatile, and cost-effective production of photovoltaic modules with consistent output voltage, reducing ohmic losses and connector costs, suitable for various luminescent solar concentrator sizes.
Implementation Method 1
photovoltaic cells arranged in modules, called arrays, which convert the fraction of luminescence radiation trapped inside said sheet/film into electrical current
Implementation Method 2
Luminescent Solar Concentrators (LSC) are devices based on a sheet or film provided with dye molecules which are able to capture a portion of incident solar radiation and re-emit it
Implementation Method 3
A portion of the radiation emitted by the dye molecules remains trapped inside the film/sheet due to the phenomenon of total internal reflection
Data Source
AI summary
Described is a flexible composite strip including a flexible printed circuit comprising at least a first and a second conductor track, a plurality of groups of photovoltaic cells being connected in parallel to said first and second tracks for supplying them; the composite strip comprises a plurality of soldering pads at which the first and second conductor tracks are accessible; the flexible composite strip is configured to be cut at the soldering pads.