Solar Cell Bus Bar Electrode Slope Design
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Solution Overview
Problem
Conventional solar cell modules face challenges in improving conversion efficiency due to restricted shapes and arrangements of electrodes and tabs, which can lead to decreased positional accuracy and durability during connections between adjacent solar cells.
Innovation Solution
The solution involves alternately arranging linear n finger electrodes and p finger electrodes on a projection plane parallel to the substrate with n-side and p-side bus bar electrodes that intersect with these electrodes and have a slope angle relative to the arrangement direction, allowing for increased design freedom and connection flexibility without inverting polarities or directions, and using a copper tub wire to connect adjacent solar cells in series.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional wiring connections are used to connect front surface and back surface electrodes of adjacent solar cells, then electrical connection is achieved, but positional accuracy decreases and damage risk increases
Solution Approach 1:
The patent inverts the conventional connection approach by connecting front surface electrodes to front surface electrodes and back surfaces to back surfaces, rather than cross-connecting front to back. This inversion eliminates the need for complex wiring through the cell stack, improving both reliability and positional accuracy
Solution Approach 2:
The patent extracts the wiring connection function from the internal structure by using bus bar electrodes that extend to the edges of the solar cell. This allows connections to be made at the perimeter rather than requiring internal wiring penetration, reducing damage risk and improving manufacturing precision
2Productivity
If both p-type and n-type regions are provided on the back surface to expand sunlight receiving area, then conversion efficiency improves, but electrode shape and arrangement become restricted
Solution Approach 1:
The patent introduces asymmetry in the bus bar electrode design, where the n-side bus bar and p-side bus bar have different configurations and positions. This asymmetric design provides freedom in optimizing electrode shapes and arrangements while maintaining the dual polarities on the back surface, enabling both high conversion efficiency and design versatility
Solution Approach 2:
The patent utilizes the dimensional space on the back surface by arranging both p-type and n-type regions in the same plane, and positioning bus bar electrodes at different locations and orientations. This two-dimensional arrangement on the back surface allows expanded sunlight reception while maintaining electrode design freedom through varied shapes and positions
3Reliability
If tabs are used to connect solar cells in series with both polarities on back surface, then electrical connection is achieved, but connection complexity and alignment requirements increase
Solution Approach 1:
The patent merges the functions of multiple connection elements by using bus bar electrodes that simultaneously serve as collection electrodes and connection terminals. This consolidation eliminates the need for separate tabs and reduces connection complexity while maintaining reliable electrical connection
Solution Approach 2:
The bus bar electrodes perform multiple functions: they collect current from finger electrodes, provide electrical connection to adjacent cells, and serve as structural anchors. This multi-functionality reduces the number of separate components needed, simplifying the overall connection structure
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 approach enhances the degrees of freedom in electrode and bus bar design, improves conversion efficiency, and simplifies the connection process between solar cells, reducing the need for precise alignment and minimizing durability issues with copper wires.
Implementation Method 1
a solar cell in which linear n finger electrodes (n finger electrode 50) and p finger electrodes (p finger electrode 60) are alternately arranged on a projection plane parallel to a main surface of a substrate (n-type crystalline Si substrate 20)
Data Source
AI summary
Provided is a solar cell in which a linear n finger electrode and a linear p finger electrode are alternately arranged on a projection plane parallel to a main surface of a substrate, and which is arranged in a predetermined arrangement direction, including an n-side bus bar electrode connected to the n finger electrode and insulated from the p finger electrode and a p-side bus bar electrode connected to the p finger electrode and insulated from the n finger electrode. The n-side bus bar electrode and the p-side bus bar electrode are provided on a same main surface side of the substrate, intersect with the n finger electrode and the p finger electrode respectively on the projection plane, and have a slope angle relative to the predetermined arrangement direction.