Back-Contact Solar Cell Layout With Ultrafine Pad-Free Busbars
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Solution Overview
Problem
Existing back-contact solar cell technologies face issues such as high silver consumption, deformation after welding, low tensile force, and low production yield due to the use of solder pads and wide main busbar lines.
Innovation Solution
The development of a non-solder pad ultrafine main busbar back-contact solar cell design, which eliminates pads on the main busbar lines and uses narrow busbar lines (10-100 μm wide) arranged at intervals, reducing silver paste consumption and improving tensile force without the need for high-temperature processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If pads are provided on the main busbar line, then the welding connection is strengthened, but the silver consumption increases and deformation occurs after high-temperature welding
Solution Approach 1:
The patent removes the pad structure from the main busbar line, extracting the problematic element that caused both high silver consumption and welding-induced deformation. The main busbar line directly connects to the finger without an intermediate pad, eliminating the source of the contradiction.
Solution Approach 2:
The patent changes the width parameter of the main busbar line to an ultrafine range (10-100 μm), which is significantly narrower than conventional busbar lines. This parameter change reduces the amount of silver paste needed while maintaining adequate electrical conductivity and mechanical strength for the application.
2Reliability
If the main busbar line width is increased, then the series resistance is reduced, but the silver consumption increases and the production capacity is affected
Solution Approach 1:
The patent optimizes the width parameter of the main busbar line to an ultrafine range (10-100 μm), balancing electrical performance with manufacturing capabilities. This parameter change allows the busbar to maintain adequate conductivity while being compatible with existing production equipment capacity.
Solution Approach 2:
The patent employs multiple main busbar lines distributed across the cell structure, segmenting the current collection function. This segmentation allows each individual busbar line to be ultrafine while the collective system maintains low series resistance through parallel current paths.
3Strength
If high-temperature welding is used to connect the welding strip to the main busbar line, then the connection strength is improved, but the cell deformation increases and production yield decreases
Solution Approach 1:
The patent removes the pad structure that concentrated thermal stress during welding, and uses ultrafine main busbar lines that require lower welding temperatures. This extraction of the problematic pad and reduction of busbar dimensions eliminates the need for high-temperature welding processes.
Solution Approach 2:
The patent changes the width parameter of the main busbar line to ultrafine dimensions (10-100 μm), which reduces the thermal mass and required welding temperature. This parameter change enables connection at lower temperatures, preventing cell deformation while maintaining adequate connection strength.
4Force
If pads are provided on the main busbar line, then the welding tension is increased, but the material cost increases due to high silver paste consumption
Solution Approach 1:
The patent removes the pad structure from the main busbar line, eliminating the additional silver paste that would be required for pad fabrication. The direct connection approach maintains adequate welding tension without the intermediate pad structure.
Solution Approach 2:
The patent changes the width parameter of the main busbar line to ultrafine dimensions (10-100 μm), which directly reduces the volume of silver paste required. This parameter change proportionally reduces material cost while maintaining functional performance.
Data Source
AI summary
The present disclosure provides a non-solder pad ultrafine main busbar back-contact solar cell, a back-contact solar cell module, and a preparation method, wherein the back-contact cell includes a first finger and a second finger, a first main busbar line, a second finger, a first insulation layer, and a second insulation layer, wherein the widths of the first main busbar line and the second main busbar line in the X-axis direction are each independently 10-100 μm; the first main busbar lines or the second main busbar lines are respectively provided in an extending manner or at intervals along the same axis perpendicular to the corresponding fingers connected thereto, and when spaced apart, the distance L between two adjacent corresponding main busbar lines in the Y-axis direction is 5-100 mm.