Solar Cell Electrode Structure with Segmented Busbars for Reliable Soldering
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Solution Overview
Problem
Existing solar cell designs with busbars suffer from poor contact between electrode pads and solder strips, leading to cold soldering and power losses due to reduced soldering tension and increased micro cracks.
Innovation Solution
The electrode structure features busbars with opposing sub-busbars having spaced first and second sub-portions, where the first sub-portions protrude away from electrode pads, allowing the solder strip to be directly connected between the sub-busbars, enhancing soldering tension and reducing micro cracks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional busbar design with continuous structure is used, then manufacturing is simple, but soldering tension is insufficient leading to cold soldering and micro cracks
Solution Approach 1:
The busbar is divided into multiple sub-busbars (first sub-busbar, second sub-busbar, third sub-busbar, fourth sub-busbar) arranged in sequence along the extending direction. Each sub-busbar has a specific width and they are spaced apart, creating discrete segments rather than a continuous structure. This segmentation increases soldering tension by distributing the soldering force across multiple contact points and prevents cold soldering and micro cracks.
2Loss of energy
If busbars are designed to reduce current transmission paths, then energy loss is reduced, but contact between electrode pads and solder strip deteriorates
Solution Approach 1:
The busbar structure extends in the first direction while sub-busbars are arranged in the second direction (width direction). The electrode pads are positioned to contact multiple sub-busbars simultaneously, creating a two-dimensional contact pattern. This dimensional arrangement allows current to be collected efficiently along the length while maintaining broad contact area with the solder strip, preventing poor contact despite reduced transmission paths.
3Reliability
If wider busbars are used to improve contact area, then soldering tension increases, but silver paste consumption increases
Solution Approach 1:
Instead of using a single wide busbar that would consume excessive silver paste, the structure segments the width into multiple narrower sub-busbars spaced apart. Each sub-busbar has an optimized width that provides sufficient soldering tension when combined with the multi-point contact of electrode pads. This segmentation reduces total silver paste consumption while maintaining or improving soldering reliability through distributed contact points.
Solution Approach 2:
Each sub-busbar has a specific width optimized for its local function of providing soldering contact points. The spacing between sub-busbars is controlled to ensure adequate soldering tension without excessive material usage. This local optimization of dimensions allows the structure to achieve high soldering reliability with minimal silver paste consumption.
Data Source
AI summary
An electrode structure, a solar cell, and a photovoltaic module are provided. The electrode structure includes: busbars extending along a first direction and each including two sub-busbars arranged opposite to each other along a second direction intersecting with the first direction, each of the sub-busbars includes first sub-portions and second sub-portions that are spaced at intervals; fingers extending along the second direction and arranged at two sides of the busbars, the fingers are connected to the sub-busbars; and electrode pads sandwiched between the first sub-portions of the two sub-busbars and connected to the first sub-portions, the first sub-portion of at least one of the sub-busbars protrude towards a side away from the electrode pads.