Offset Contact Wire Arrays in Photovoltaic Modules
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Solution Overview
Problem
Photovoltaic modules face efficiency losses due to shading from contact patterns and mechanical stresses from busbars, and existing methods for connecting contact wires to solar cells require supportive materials that increase costs and complexity.
Innovation Solution
A photovoltaic module design featuring offset contact wire arrays on the front and rear of solar cells, eliminating the need for busbars and supportive materials, with contact wires arranged in a weaving pattern to reduce shading and mechanical stress, and using solder or adhesive joints for attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the width of contact patterns is increased, then the line resistance is reduced, but the shading on the front surface increases leading to efficiency loss
Solution Approach 1:
The contact pattern is divided into multiple parallel contact fingers instead of a single wide busbar. This segmentation allows the current to be distributed across multiple narrower paths, reducing the shading effect on the photovoltaic layer while maintaining sufficient current carrying capacity through the combined cross-sectional area of all fingers.
Solution Approach 2:
The contact wires are arranged in a three-dimensional configuration with some wires extending from the front surface and others from the rear surface of the photovoltaic cell. This spatial arrangement allows current collection from both surfaces, effectively utilizing the third dimension to reduce front surface shading while maintaining electrical connectivity.
2Reliability
If busbars are used to combine current from contact patterns, then the electrical connection is improved, but the shading on the front surface increases
Solution Approach 1:
Instead of using a single wide busbar, the current collection is segmented into multiple thin contact fingers distributed across the cell surface. This segmentation reduces the total width of conductive material on the front surface, minimizing shading losses while maintaining electrical connection reliability through multiple parallel pathways.
Solution Approach 2:
The patent utilizes both front and rear surfaces of the photovoltaic cell for current collection. Contact wires are attached to contact patterns on the front surface and extend to the rear surface, creating a three-dimensional current collection architecture that reduces front surface shading while ensuring reliable electrical connection.
3Loss of energy
If contact wires are made thin to reduce shading, then the shading loss is reduced, but the handling and positioning of the wires becomes difficult
Solution Approach 1:
An adhesive layer is introduced as an intermediary between the thin contact wires and the photovoltaic cell. This adhesive mediator facilitates the handling and positioning of thin wires during manufacturing by providing a bonding interface, while the wires themselves remain thin to minimize shading losses during operation.
Solution Approach 2:
The patent replaces mechanical connection methods (such as soldering or clamping) with adhesive bonding for attaching contact wires to the photovoltaic cell. This substitution allows thin wires to be securely positioned without requiring complex mechanical fixtures or high-precision alignment mechanisms, easing the handling and positioning process while maintaining electrical connectivity.
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 enhances efficiency by minimizing shading and mechanical stress, reduces material costs, and simplifies the connection process while maintaining effective electrical connectivity between solar cells.
Implementation Method 1
The contact pattern typically has a width of at least 100 μm whilst its thickness is only about 10 μm to 15 μm. A greater width of the contact pattern leads to a reduction in the efficiency due to the resultant increased shading
Implementation Method 2
A photovoltaic cell (for example a solar cell) usually exhibits a layer of semiconductor material, for example silicon (also called photovoltaic layer in the text which follows)
Data Source
AI summary
In various embodiments, a photovoltaic module may include: a plurality of photovoltaic cells, at least one photovoltaic cell of the number of photovoltaic cells comprising: a first plurality of contact wires on a front of the photovoltaic cell; and a second plurality of contact wires on a rear of the photovoltaic cell. The first plurality of contact wires and the second plurality of contact wires may be arranged offset with respect to one another.