Silicon Wafer Extension Edge Layout for Dense PV Cell Overlap
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Solution Overview
Problem
Existing photovoltaic modules with monocrystalline and polycrystalline silicon wafers suffer from low efficiency and power output due to low arrangement density of cell slices, sheet gaps, and overlapping areas that shield light during stitch-welding.
Innovation Solution
The silicon wafers are designed with an extension edge that overlaps below adjacent wafers during welding, eliminating sheet gaps and increasing arrangement density, using leftovers for power generation and stitch-welding, and incorporating main grid lines perpendicular to the extension edges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional silicon wafers are used in photovoltaic modules, then the module assembly process is simple, but the modules suffer from hot spot phenomena, micro-cracks, and delamination reducing reliability
Solution Approach 1:
The silicon wafer is divided into multiple independent ribs that are separated by grooves. Each rib acts as an independent support structure for solar cell strings, preventing the propagation of micro-cracks and delamination across the entire module. The grooves create physical separation zones that isolate stress and damage, thereby improving overall module reliability without requiring complete structural redesign.
Solution Approach 2:
The patent implements a hierarchical nesting structure where solar cell strings are nested within grooves, which are nested within ribs, which are nested within the silicon wafer substrate. This nested arrangement provides multiple levels of mechanical support and protection, preventing direct contact between adjacent cell strings and eliminating the conditions that lead to hot spots and delamination.
2Reliability
If silicon wafers with ribs and grooves are used, then module reliability improves by preventing hot spots and micro-cracks, but the manufacturing process becomes more complex
Solution Approach 1:
The ribs and grooves are pre-formed into the silicon wafer substrate before solar cell installation. This preliminary structuring allows for standardized manufacturing processes where the wafer arrives at the assembly stage with its support structure already in place, simplifying the overall manufacturing workflow despite the added structural complexity. The pre-formed geometry enables automated assembly processes.
3Ease of manufacture
If conventional flat silicon wafers are used, then manufacturing is simpler, but electrical connection issues and performance degradation occur
Solution Approach 1:
The silicon wafer is designed with localized variations in structure: flat regions for optimal solar cell contact and rib structures for mechanical support and electrical connection. Each region of the wafer has different properties tailored to its specific function, ensuring precise electrical connections at the cell-wafer interface while maintaining overall manufacturing feasibility through standardized rib patterns.
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 the power and efficiency of photovoltaic modules by increasing the effective power generation area and reducing sheet gaps, while utilizing silicon material more effectively and reducing production costs.
Implementation Method 1
an n-type silicon wafer having a plurality of ribs extending in a first direction, the plurality of ribs being separated from each other by grooves extending in the first direction
Data Source
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AI summary
The invention discloses a silicon wafer and a preparation method therefor, a cell sheet, a cell slice, a cell string, and a photovoltaic module. The monocrystalline silicon wafer comprises a silicon wafer main body and an extension edge that extends outwards from an edge of the silicon wafer main body, the silicon wafer main body is a right-angled square slice or a rounded square slice, the extension edge is a ribbon-shaped structure parallel to the edge of the silicon wafer main body, and the extension edge is used to overlap below the adjacent monocrystalline silicon wafer during welding. By making the extension edge overlap below the adjacent cell sheet or cell slice, a sheet gap is reduced, an increase in an arrangement density of the cell sheets or cell slices is facilitated, and an efficiency of a photovoltaic module is increased. Since the adjacent cell sheet or cell slice shields the extension edge rather than the silicon wafer main body, the area of the cell sheet or cell slice involved in power generation is increased, and an increase in the power of the photovoltaic module is facilitated.