Multi-junction Solar Cell Parallel Architecture
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Solution Overview
Problem
Multi-junction solar cells face efficiency limitations due to differences in current values between layers, which are connected in series, leading to suboptimal conversion efficiency unless multiple power converters are used.
Innovation Solution
A multi-junction solar cell design where a first solar cell is connected in parallel with a second solar cell, with an insulating layer between them, allowing multiple second photoelectric conversion elements to be connected in series, and featuring p- and n-electrodes opposing each other to equalize photon absorption and voltage matching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If layers are connected in series, then voltage is increased, but conversion efficiency is limited by the layer with lowest current value
Solution Approach 1:
The solar cell is divided into multiple independent photoelectric conversion layers (first layer, second layer, third layer) that can be connected in parallel. Each layer absorbs photons of different energy ranges and generates current independently, allowing the system to overcome the series connection limitation where the lowest current layer restricts overall efficiency.
Solution Approach 2:
The patent transitions from traditional series connection (one-dimensional voltage stacking) to parallel connection architecture, adding a new dimensional approach to multi-junction solar cells. This parallel configuration allows independent current generation from each layer while maintaining voltage addition through the insulating layer structure.
2Productivity
If multiple power converters are used to avoid efficiency limits, then conversion efficiency can be maintained, but device complexity increases
Solution Approach 1:
The patent merges multiple photoelectric conversion layers into a single integrated solar cell structure with parallel connections. The insulating layers are strategically positioned to enable direct parallel connection of multiple p-n junctions within one cell, eliminating the need for separate power converters while maintaining high conversion efficiency through unified current collection.
Solution Approach 2:
The insulating layer serves multiple functions: it provides electrical isolation between series-connected cells, enables parallel connection pathways, and facilitates current collection from multiple layers simultaneously. This multi-functional design eliminates the need for additional power converter components.
3Productivity
If parallel connection is implemented, then conversion efficiency improves through voltage and current matching, but manufacturing precision requirements increase
Solution Approach 1:
The insulating layers are pre-positioned and patterned during the manufacturing process to create predetermined connection pathways. The first and second insulating layers are formed with specific patterns that guide the alignment of electrodes before the actual electrode deposition, making the parallel connection process more tolerant to manufacturing variations.
Solution Approach 2:
The insulating layers act as intermediary elements that facilitate precise alignment and connection between electrodes of different layers. These insulating structures provide physical guides and electrical isolation that simplify the alignment process during manufacturing, reducing the precision requirements compared to direct electrode-to-electrode alignment.
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 conversion efficiency by voltage and current matching between the solar cells, reducing the need for multiple power converters and improving overall performance.
Implementation Method 1
a first photoelectric conversion element, a second photoelectric conversion element... The second photoelectric conversion element includes a p-electrode and an n-electrode
Data Source
AI summary
According to one embodiment, a multi-junction solar cell includes a first solar cell, a second solar cell, and an insulating layer. The first solar cell includes a first photoelectric conversion element. The second solar cell is connected in parallel with the first solar cell. The second solar cell includes multiple second photoelectric conversion elements connected in series. The insulating layer is provided between the first solar cell and the second solar cell. The second photoelectric conversion element includes a p-electrode and an n-electrode. The p-electrode is connected to a p+-region including a surface on a side opposite to a light incident surface. The n-electrode is connected to an n+-region including the surface on the side opposite to the light incident surface. The p-electrodes oppose each other or the n-electrodes oppose each other in a region where the multiple second photoelectric conversion elements are adjacent to each other.