Photovoltaic Module Solder Strip Boss Geometry for Lamination Stress
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Solution Overview
Problem
Photovoltaic modules are prone to damage and have low yield, affecting their service life and manufacturing costs.
Innovation Solution
A photovoltaic module design featuring solar cells with a semiconductor substrate and passivation layer, including busbars, fingers, and electrode pads, connected by solder strips with a boss portion that has a controlled gradient to prevent stress during lamination, ensuring stable connections and reducing fragmentation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional solder strips are used to connect solar cells, then manufacturing process is simple, but solar cells are prone to fragmentation and damage during lamination
Solution Approach 1:
The boss portion is pre-formed on the solder strip with a specific gradient structure (0° to 10°) before the lamination process. This preliminary structural preparation ensures that when the solar cell is laminated, the stress is already optimized to prevent fragmentation, rather than relying on post-processing or complex real-time adjustments
Solution Approach 2:
The solder strip structure is modified by introducing a boss portion with controlled gradient parameters (0° to 10° along the extension direction, 200-300 microns distance from solar cell). These parameter changes optimize the stress distribution during lamination, preventing solar cell fragmentation while maintaining manufacturing feasibility
2Productivity
If solar cells are connected with traditional methods, then manufacturing cost is lower, but yield is reduced due to damages
Solution Approach 1:
Instead of modifying the entire solder strip uniformly, only a localized boss portion is added at the connection point with specific gradient characteristics. This local modification approach improves connection reliability and reduces fragmentation at critical areas without significantly complicating the overall manufacturing process
Solution Approach 2:
The boss portion with optimized gradient is pre-formed on the solder strip before assembly. This preliminary structuring prevents damage during lamination, thereby improving manufacturing yield without requiring complex post-processing or specialized manufacturing equipment
3Strength
If solder strips with vertical boss portions are used, then connection area is maximized, but stress concentration causes solar cell fragmentation
Solution Approach 1:
The boss portion gradient angle is changed from vertical (90°) to a controlled range of 0° to 10° along the extension direction. This parameter change redistributes the stress during lamination, preventing stress concentration that would cause fragmentation while maintaining adequate connection strength through the controlled gradient structure
Solution Approach 2:
The boss portion structure, which could potentially create stress concentration, is redesigned with a specific gradient (0° to 10°) that converts the potential harmful stress into a beneficial stress distribution. The gradient allows gradual stress transfer from the solder strip to the solar cell, preventing sudden stress concentration and fragmentation
Data Source
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AI summary
A photovoltaic module, including a plurality of solar cells each including a semiconductor substrate and a passivation layer, the semiconductor substrate is provided with an electrode including busbars, fingers, and electrode pads, each of the solar cells includes 9 to 20 busbars, each of the solar cells includes 40 to 100 fingers, and each of the busbars is connected to 3 to 10 electrode pads; a plurality of solder strips configured to connect the plurality of solar cells to each other, each of the solder strips fits the busbars and includes at least one boss portion soldered with the electrode pads, and a gradient of an outer surface of the boss portion along an extension direction of the solder strip ranges from 0° to 10°.