IBC Solar Cell Busbar Pits for Stable Soldering and Short-Circuit Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Interdigitated back contact (IBC) solar cells face challenges with soldering tension between solar cells and solder strips, leading to potential short circuits and poor assembly due to the use of insulating paste.
Innovation Solution
The design includes busbar pits on the substrate with specific dimensions and arrangements of busbars and fingers, allowing solder strips to be partially embedded within these pits, enhancing soldering tension and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If insulating paste is applied around busbars to prevent short circuit, then short circuit prevention is improved, but soldering tension between solar cells and solder strips deteriorates
Solution Approach 1:
The busbar structure is segmented into multiple components: busbar body, busbar pits, and soldering regions. The busbar pits are divided into first pits and second pits with different depths, creating distinct functional zones for electrical connection and soldering attachment, thereby resolving the conflict between insulation and soldering tension.
Solution Approach 2:
Different regions of the busbar are given different properties: the busbar body provides electrical conduction, the first pits provide insulation and short circuit prevention, while the second pits provide enhanced soldering tension through deeper embedding. This local differentiation allows simultaneous achievement of both short circuit prevention and strong soldering.
2Strength
If busbar pits are etched with specific depth ratios to improve soldering tension, then soldering tension is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent specifies parameter ranges rather than fixed values: the depth ratio of first pits to busbar height is 0.2-0.5, and second pits to busbar height is 0.5-0.8. These ranges provide manufacturing tolerance while ensuring sufficient soldering tension, reducing the stringency of precision requirements.
Solution Approach 2:
The busbar pits are pre-formed during the busbar manufacturing process before the actual soldering operation. This preliminary structuring ensures that the pits are already in place with correct dimensions, simplifying the subsequent soldering process and reducing the need for high-precision adjustments during assembly.
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
Disclosed is solar cell, a photovoltaic module, and a method for manufacturing a photovoltaic module. The solar cell includes a substrate, first busbars and second busbars arranged on the substrate, first fingers connected to the first busbars, and second fingers connected to the second busbars. The first busbars and the second busbars have opposite polarities. The first fingers have a same polarity as the first busbars, and the second fingers have a same polarity as the second busbars. The substrate is provided with busbar pits. At least part of the first and second busbars are located in the busbar pits. Depths of the busbar pits range from 30 µm to 50 µm. Along a thickness direction of the substrate, ratios of the depths of the busbar pits to heights of the first busbars and/or the second busbars range from 10:3 to 6:5.