Parallel-Connected Photovoltaic Layers for Current Production
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Solution Overview
Problem
Conventional tandem photovoltaic devices are complex and costly due to their requirement for multiple layers and materials, with current limitations in series connection leading to inefficiencies in current production and sensitivity to light spectrum variations.
Innovation Solution
A photovoltaic device structure with layers connected in parallel, allowing each layer to operate at the same voltage, and including a crystalline silicon layer as a support with germanium or germanium-silicon layers connected in series to enhance current production without limiting other layers, reducing complexity and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional series connection of multiple layers is used in tandem photovoltaic devices, then voltage is increased through stacking, but current production is limited by the weakest layer and sensitivity to light spectrum variations increases
Solution Approach 1:
The device is segmented into multiple independent layers (first layer with wide band gap, second layer with intermediate band gap, third layer with narrow band gap), where each layer can be optimized independently for its specific band gap characteristics without being constrained by series connection requirements
Solution Approach 2:
Instead of the conventional series connection approach where layers are stacked to increase voltage, this invention uses parallel connection where layers are arranged to increase current production while maintaining the same voltage, inverting the traditional voltage-focused stacking approach
2Productivity
If multiple layers with different band gaps are stacked in conventional tandem structure, then efficiency is improved through spectral utilization, but device complexity and manufacturing cost increase
Solution Approach 1:
The photovoltaic device is divided into three distinct layers, each with a specific band gap optimized for different portions of the solar spectrum, allowing independent optimization of each layer's material composition and thickness to achieve high efficiency while managing complexity through modular design
Solution Approach 2:
Each layer serves multiple functions: the first layer (wide band gap) captures high-energy photons and provides structural support, the second layer (intermediate band gap) captures mid-energy photons and bridges the spectral gap, and the third layer (narrow band gap) captures low-energy photons, with each layer being transparent to lower-energy photons for sequential absorption
3Power
If conventional series connection is used in tandem cells, then voltage is maximized, but the cell producing less photocurrent limits the current delivered by the entire array
Solution Approach 1:
The invention inverts the conventional series connection approach by using parallel connection, where all layers operate at the same voltage but contribute additively to current production, eliminating the bottleneck effect where the weakest layer limits overall performance
Solution Approach 2:
The patent merges the current production capabilities of multiple layers with different band gaps by connecting them in parallel, combining their individual current contributions to achieve higher total current delivery while maintaining consistent voltage across all layers
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 structure increases efficiency by optimizing voltage and current production, making the device more robust to light variations and reducing material costs, achieving a 20% relative gain in current production compared to traditional silicon cells.
Implementation Method 1
a plurality of layers configured to convert light (L) into electric energy
Implementation Method 2
The width of the band gap of a semiconductor determines the minimum energy of the photons which can be absorbed by that material, which will appear to be transparent for less energetic photons
Data Source
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AI summary
The present invention relates to a photovoltaic device having a plurality of layers (11, 12, 13) configured to convert light (L) into electric energy. Each layer comprises at least one solar cell (11A; 12A, 12B; 13A, 13B, 13C, 13D). Each layer is configured such that it has a band gap with a predetermined width, the width of the band gap of each layer being different from the width of the band gap of the other layers. At least one of the layers (12, 13) comprises at least two solar cells (12A, 12B; 13A, 13B, 13C, 13D) connected in series and having band gaps with the same width. The layers are connected to one another in parallel, such that the voltage (U) on each layer (11, 12, 13) is the same. The invention also relates to a photovoltaic panel.