Solar Cell Electrode Layout for Crack-Free Series Welding
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Solution Overview
Problem
The existing solar cell assembly process is prone to hidden cracking at the starting welding spot between solar cells and photovoltaic solder strips due to mismatched distances of front and back electrodes, affecting efficiency and reliability.
Innovation Solution
The solar cell design features front and back electrodes with strategically aligned projections and varying end segment lengths to offset welding stresses, ensuring that the projections of the starting points of both electrode types coincide, allowing for balanced stress distribution during series welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the front electrodes and back electrodes are arranged with different distances from the edge to optimize light receiving area and convergence efficiency, then the electrode configuration improves photovoltaic performance, but hidden cracking occurs at the starting welding spot between solar cells and photovoltaic solder strip
Solution Approach 1:
The patent applies asymmetry by deliberately designing different electrode configurations for the front and back surfaces. Specifically, the front electrode starts at a position closer to the edge to maximize light receiving area, while the back electrode starts at a position farther from the edge. This asymmetric arrangement, combined with the photovoltaic solder strip having different starting positions on each surface, creates a balanced stress distribution that prevents hidden cracking while maintaining optimal photovoltaic performance.
2Area of moving object
If the front electrodes are positioned closer to the edge to increase light receiving area, then the convergence efficiency improves, but the welding stress at the starting point increases and cannot be offset by back electrode stresses
Solution Approach 1:
The patent applies the counterweight principle by designing the back electrode and photovoltaic solder strip configuration to compensate for the asymmetric front electrode placement. The back electrode is positioned farther from the edge, and the photovoltaic solder strip is configured with different starting positions on the front and back surfaces, creating opposite-direction stresses that offset each other and balance the overall welding stress distribution.
3Device complexity
If the same electrode starting distance is used on both front and back surfaces, then the welding stress distribution is simplified, but the light receiving area and convergence efficiency are reduced
Solution Approach 1:
The patent applies local quality by optimizing the electrode configuration independently for each surface based on its specific functional requirements. The front surface electrodes are positioned to maximize light receiving area and convergence efficiency, while the back surface electrodes are positioned to facilitate proper welding stress distribution. This localized optimization ensures that each surface has the electrode configuration best suited to its specific function.
Data Source
AI summary
A solar cell includes: a first surface, a second surface, a first side surface and a second side surface; wherein first electrode strips are provided on the first surface, and second electrode strips are provided on the second surface; the first electrode strips include first discontinuous electrodes, each including at least two first electrode segments, and the second electrode strips include second discontinuous electrodes, each including at least two second electrode segments; and the first electrode segments include a first end electrode segment adjacent to the first side surface, the second electrode segments include a second end electrode segment adjacent to the first side surface, and a length of the first end electrode segment is different from a length of the second end electrode segment.