Zero-Busbar PV Cell String Soldering Without Front-Side Pressing
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Solution Overview
Problem
The existing process for stringing zero-busbar photovoltaic cells into a cell string results in uneven heating, leading to issues such as bubbling of the film layer and poor soldering due to the use of a pressing tool and infrared heating, which causes pre-crosslinking and solder strip shifting.
Innovation Solution
A method involving pre-fixing solder strips onto zero-busbar photovoltaic cells using a pre-fixing adhesive film, followed by heating and pressurizing the front film layer without a pressing tool, ensuring uniform heating and preventing bubbling and poor soldering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a pressing tool is used on the front side to fix the front film layer and solder strips during infrared heating, then the film layer is fixed in position, but uneven heating temperatures occur across the photovoltaic cell surface, causing bubbling and poor soldering
Solution Approach 1:
The patent applies a back film layer to the rear surface of the photovoltaic cell before heating, which serves as a preliminary fixing measure. This back film layer is heated and pressed from the rear side, pre-stabilizing the cell structure before the front film layer is applied, thereby avoiding the need for a pressing tool on the front side during heating and preventing uneven heating
Solution Approach 2:
Instead of applying and pressing the front film layer from the front side (conventional approach), the patent inverts the approach by applying and pressing the back film layer from the rear side. This reversal eliminates the pressing tool interference on the front surface, allowing uniform infrared heating and preventing bubbling and poor soldering
2Stability of the object's composition
If the front film layer is heated by infrared lamp with a pressing tool in place, then the film layer is fixed, but pre-crosslinking occurs within the film layers, causing the front film layer to adhere to the pressing tool and the back film layer to adhere to the belt, leading to solder strip shifting
Solution Approach 1:
The back film layer is applied and heated in advance before the front film layer is fully processed. This preliminary heating and pressing of the back film layer creates a stable base that prevents excessive adhesion during subsequent front film layer processing, thereby preventing solder strip shifting
Solution Approach 2:
The patent removes the pressing tool from the front side during heating, extracting the source of excessive pressure that causes pre-crosslinking and adhesion to the pressing tool. By eliminating this element, the process avoids film layer adhesion to the pressing tool and prevents solder strip shifting
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
The solution ensures high-quality soldering between the solder strip and the photovoltaic cell, reduces finger breakage, and prevents film layer bubbling by applying pressure on the front side, enhancing the efficiency and reliability of the soldering process.
Implementation Method 1
performing heating to pre-fix each solder strip onto a surface of the corresponding zero-busbar photovoltaic cell
Implementation Method 2
heat and pressurize the front film layer
Implementation Method 3
heat and pressurize the front film layer
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
A zero-busbar photovoltaic cell string soldering method and a zero-busbar photovoltaic cell string soldering apparatus. The method comprises: conveying zero-busbar photovoltaic cells and solder strips to a pre-soldering device, and performing heating so that each solder strip is pre-fixed on the surface of the corresponding zero-busbar photovoltaic cell, so as to obtain a cell string column; and conveying the cell string column to a position below a heating and pressurizing device, controlling the heating and pressurizing device to move to be in contact with a front film layer on the cell string column, and heating and pressurizing the front film layer to obtain a cell string. The cells and the solder strips are pre-fixed, then film laminating is performed, and the front film layer is heated and pressurized. During heating and pressurizing, it is not needed to place a pressing tool on a front surface, thereby avoiding uneven heating, avoiding the problems of bubbling of a film layer and a cold solder joint, ensuring the soldering quality, reducing the cold solder joint and grid breaking. When pre-soldering is finished, heating and pressurizing are carried out, thereby preventing the solder strip from deviating.