Tandem Solar Cell String Layout for Compact Insulated Connections
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Solution Overview
Problem
Tandem solar cells with a four-terminal structure face challenges in maintaining efficient power generation when sunlight deviates from optimal irradiation conditions due to complex insulation requirements between top and bottom cell modules, leading to increased complexity and size.
Innovation Solution
The design includes a top cell string and a bottom cell string arranged to overlap in the thickness direction with a first extending portion for the bottom cell strings electrically connected to a module, ensuring insulation while maintaining efficient power generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If string connections of top cell module and bottom cell module are arranged close to each other in the thickness direction, then space utilization is improved, but insulation reliability between string connections deteriorates
Solution Approach 1:
The patent extends string connections in the planar direction (another dimension) rather than only in the thickness direction. The first string connection has a first extending portion extending in the planar direction from the top cell module, and the second string connection has a second extending portion extending in the planar direction from the bottom cell module. This dimensional change allows sufficient insulation distance to be maintained while still achieving compact vertical stacking.
Solution Approach 2:
The string connections are segmented into multiple portions: a connecting portion connected to the cell module, and an extending portion extending outward. This segmentation allows the connection structure to fulfill both electrical connection function and insulation function in different spatial regions, resolving the conflict between compact arrangement and insulation reliability.
2Reliability
If insulating structure is provided between string connections, then insulation reliability is improved, but device complexity increases
Solution Approach 1:
The string connection structure itself provides insulation through its geometric arrangement and material properties. The extending portions are configured to maintain sufficient distance between top and bottom cell module string connections, allowing the structure to serve its own insulation function without requiring additional insulating components.
Solution Approach 2:
The extending portions of string connections act as intermediary elements that spatially separate the electrical connection functions from the insulation requirements. By extending these portions in the planar direction, they mediate between the need for electrical connectivity and the need for electrical insulation between stacked modules.
3Reliability
If insulating structure is provided between string connections, then insulation reliability is improved, but physical size increases
Solution Approach 1:
The patent utilizes the planar direction (another dimension) for extending string connections rather than increasing insulation distance in the thickness direction. This allows insulation to be achieved through lateral separation while maintaining compact vertical stacking, thus improving insulation reliability without significantly increasing overall physical size.
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 configuration simplifies the insulation structure, reduces complexity, and enhances power generation efficiency under varying sunlight conditions by optimizing current matching and reducing physical size.
Implementation Method 1
A tandem solar cell that includes a top cell and a bottom cell is conventionally known. The tandem solar cell can efficiently generate power in a small area by combining a top cell and a bottom cell made of materials having light absorption bands different from each other.
Data Source
AI summary
A tandem solar cell according to an embodiment includes a top cell string, a bottom cell string, a top cell module, a first string connection, a bottom cell module, and a second string connection. The top cell string is formed by electrically connecting a plurality of top cells. The bottom cell string is formed by electrically connecting a plurality of bottom cells. The bottom cell string is arranged so as to overlap the top cell string in a plan view in a thickness direction of the top cell. The first string connection includes a first extending portion extending to an outside of the top cell module in the plan view. A plurality of bottom cell strings are electrically connected to the bottom cell module. The first extending portion and the second extending portion are arranged apart from each other in the plan view.