Photovoltaic Cell Module Busbar Fixing With Lower Silver Paste Use
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Solution Overview
Problem
The high consumption of silver paste in photovoltaic cell modules, particularly in shingled modules with busbarless photovoltaic cells, and the challenges of thermal expansion leading to silicon wafer damage, hinder the development of efficient and cost-effective photovoltaic systems.
Innovation Solution
A photovoltaic cell module design that uses a grid line supporting layer and a grid line bonding layer to mechanically fix interconnected busbars to the surface of photovoltaic cells, reducing the need for silver paste and minimizing thermal stress, while allowing for thin silicon wafers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If busbarless photovoltaic cells with Ag paste pads are used for electrical connection, then electrical connection is achieved, but Ag paste consumption increases significantly
Solution Approach 1:
The patent introduces an adhesive film electrode as an intermediary component between the photovoltaic cell and the multi-busbar welding strip. This adhesive film electrode provides both mechanical adhesion and electrical conduction, replacing the need for extensive Ag paste pads while ensuring reliable electrical connection. The adhesive film acts as a mediator that transfers both mechanical stress and electrical current between the two components.
2Reliability
If multiple Ag paste pads are provided for mechanical fixation, then mechanical fixation reliability is ensured, but Ag paste consumption increases
Solution Approach 1:
The adhesive film electrode serves as a dual-function intermediary that simultaneously provides mechanical adhesion and electrical conduction. By integrating both functions into a single component, the patent eliminates the need for separate Ag paste pads for mechanical fixation, thereby reducing Ag paste consumption while maintaining fixation reliability.
Solution Approach 2:
The adhesive film electrode performs multiple functions: it provides mechanical adhesion between the welding strip and the photovoltaic cell, ensures electrical conduction, and distributes thermal stress. This multi-functional design replaces the need for separate components that would otherwise require additional Ag paste, achieving cost reduction without sacrificing performance.
3Strength
If thermal expansion and contraction of welding strips occur during cold and hot cycles, then welding strips are fixed to cells, but cutting effect wears out Ag finger lines or ITO conductive layers
Solution Approach 1:
The adhesive film electrode acts as a buffer intermediary between the welding strip and the photovoltaic cell. It absorbs and distributes the thermal stress generated during cold and hot cycles, preventing the direct transmission of cutting effects to the Ag finger lines or ITO conductive layers. This intermediary layer protects the sensitive conductive structures from thermal fatigue damage.
Solution Approach 2:
The adhesive film electrode provides beforehand cushioning by being positioned between the welding strip and the photovoltaic cell before thermal cycling occurs. It预先 absorbs and mitigates the thermal expansion and contraction forces, preventing them from reaching harmful levels that would damage the Ag finger lines or ITO conductive layers during subsequent thermal cycles.
4Quantity of substance
If silicon wafers are thinned to reduce cost, then material cost decreases, but thermal expansion mismatch causes silicon wafer damage
Solution Approach 1:
The adhesive film electrode serves as a stress-absorbing intermediary between the thin silicon wafer and the welding strip. It compensates for the thermal expansion mismatch between materials, distributing thermal stresses evenly across the thin wafer surface. This prevents stress concentration that would otherwise cause cracking or damage to the thinned silicon wafer during thermal cycling.
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
Significantly reduces silver paste consumption, lowers manufacturing costs, and enhances the reliability of photovoltaic modules by evenly distributing thermal stress, thereby reducing silicon wafer breakage and maintaining efficient power generation.
Implementation Method 1
the grid line supporting layer adheres to the surfaces of the photovoltaic cells by a bonding effect of the grid line bonding layer
Implementation Method 2
The surfaces of the interconnected busbars have low melting-point welding layers, and electrical contacts are formed between the interconnected busbars and the photovoltaic cells by means of the low melting-point welding layers
Implementation Method 3
Photovoltaic cells in the photovoltaic cell layer derive a current
Data Source
AI summary
A photovoltaic cell module includes a photovoltaic cell layer, conductive or non-conductive connection points between photovoltaic cells and interconnected busbars, a grid line bonding layer and a grid line supporting layer provided on surfaces of the photovoltaic cells. The grid line supporting layer adheres to the surfaces of the photovoltaic cells by a bonding effect of the grid line bonding layer. The grid line supporting layer is laminated on the interconnected busbars. A method of manufacturing the module includes: firstly, preliminarily fixing interconnected busbars on the surfaces of photovoltaic cells via conductive or non-conductive connection points; then covering the surfaces of the photovoltaic cells with a grid line supporting layer and a grid line bonding layer, applying pressure on the grid line supporting layer and the grid line bonding layer, and completely fixing the interconnected busbars to the surfaces of the photovoltaic cells by the grid line supporting layer.