Solar Cell Interconnect Bonding Without Silver Paste
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Solution Overview
Problem
The existing connection methods for cells and interconnect wires in PV power generation are costly due to the use of silver paste, which accounts for over 20% of the cell assembly cost, and suffer from low adhesion between the solder alloy, copper, and the cell.
Innovation Solution
A connection structure that eliminates the need for silver paste by using a bonding mechanism, such as a positioning adhesive tape, to secure the interconnect wires directly to the cell, along with reinforcing and connecting grids made of silver paste to enhance current transmission and strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If silver paste is used to connect interconnect wires to cells, then connection strength is improved, but manufacturing cost increases significantly
Solution Approach 1:
The patent extracts and removes the silver paste from the connection structure, replacing it with a bonding mechanism consisting of a positioning adhesive tape and soldering process. This eliminates the expensive silver paste material while maintaining connection functionality through alternative bonding methods.
Solution Approach 2:
The patent replaces expensive silver paste with a cheaper bonding mechanism using positioning adhesive tape and standard soldering materials. The adhesive tape serves as a temporary positioning element during assembly, enabling cost-effective connection without relying on costly silver paste.
2Ease of manufacture
If solder alloy and copper are used directly to connect to cells, then manufacturing cost is reduced, but adhesion to the cell deteriorates
Solution Approach 1:
The patent introduces a positioning adhesive tape as an intermediary element between the interconnect wire and the cell. This adhesive tape facilitates proper positioning and initial bonding, enabling the solder alloy to adhere effectively to the cell surface through a controlled bonding process.
Solution Approach 2:
The positioning adhesive tape performs preliminary positioning and temporary bonding of the interconnect wire to the cell before the final soldering process. This preliminary action ensures correct alignment and initial adhesion, preparing the structure for effective solder bonding to the cell.
3Ease of manufacture
If silver paste is eliminated and bonding mechanism is used, then manufacturing cost is reduced, but connection reliability may deteriorate
Solution Approach 1:
The bonding process is segmented into multiple stages: initial positioning using adhesive tape, followed by soldering of the solder alloy to the cell, and reinforcement with grid structures. This segmentation ensures each bonding stage contributes to overall connection reliability without requiring expensive silver paste.
Solution Approach 2:
The patent employs a composite bonding structure combining positioning adhesive tape, solder alloy, and grid reinforcement elements. This composite approach distributes bonding functions across multiple materials and mechanisms, ensuring reliable connections through combined effects rather than relying on a single expensive material.
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 solution reduces costs by eliminating silver paste, increases connection strength, and improves current transmission efficiency, while also reducing the risk of yellowing due to outdoor aging and allowing for low-temperature interconnection processes.
Implementation Method 1
a bonding mechanism arranged between the interconnect wires and the cell, wherein the bonding mechanism wraps the interconnect wires from outer sides and then bonds to the cell
Implementation Method 2
The solder alloy has a low melting point, which makes it easy to melt. However, neither the solder alloy nor the copper can connect well with the cell itself, resulting in low adhesion
Implementation Method 3
The solder alloy can fuse better with the busbar, which improves the bonding strength
Implementation Method 4
The reinforcing grid serves to facilitate the collection of current to the outermost interconnect wire and reduces resistance. The connecting grid prevents local breakage and facilitates current flow
Data Source
AI summary
Disclosed is connection structure for cell and interconnect wires, including cell and multiple parallel interconnect wires placed on the cell, and bonding mechanism arranged between the interconnect wires and the cell, wherein the bonding mechanism wraps the interconnect wires from outer sides and then bonds the interconnect wires to the cell, so as to fix the interconnect wires to the cell. Cell assembly includes the above connection structure for the cell and the interconnect wires, the interconnect wires are provided on both an upper side and a lower side of the cell, and the cell assembly further includes front adhesive film layer arranged on the upper side of the cell, upper glass arranged on an upper side of the front adhesive film layer, back adhesive film layer arranged on the lower side of the cell, and cover plate arranged on the lower side of the back adhesive film layer.