Solar Cell Converging Busbar Layout for Lower Silver and Solder Use

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Solution Overview

Problem

The photovoltaic industry faces challenges in controlling costs due to fluctuating prices of silver paste and solder strips, with existing busbar electrode designs struggling to reduce consumption effectively, leading to bottlenecks in cost management.

Innovation Solution

A solar cell design featuring a converging busbar that separates the cell into regions with specific sub-busbar and main busbar configurations, reducing the need for silver paste and solder strips by optimizing current collection and transfer paths, and eliminating soldering spots on certain regions to minimize material usage and risk of micro-cracks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If existing busbar electrode design is used, then current collection is achieved, but consumption of silver paste cannot be reduced effectively

Engineering Contradiction:

Improvesilver paste consumptionVSAvoidcurrent collection efficiency

Core Design Contradiction:

Loss of substanceVSReliability

Solution Approach 1:

The busbar electrode is divided into main busbars and sub-busbars. The main busbars collect current from multiple sub-busbars, creating a hierarchical collection structure. This segmentation allows optimized silver paste distribution where main busbars use thicker paste for high-current areas while sub-busbars use thinner paste, reducing overall consumption while maintaining collection efficiency.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the busbar electrode are assigned different paste thicknesses and configurations. Areas with higher current density receive thicker paste applications, while lower-density areas use thinner applications. This local quality optimization reduces total silver paste consumption while ensuring adequate current collection where needed most.

Inventive Principle:

Principle #3Local quality

2Loss of substance

If conventional solder strip connection is used, then electrical connection between cells is achieved, but cost increases due to rising solder strip prices

Engineering Contradiction:

Improvesolder strip consumptionVSAvoidconnection reliability

Core Design Contradiction:

Loss of substanceVSManufacturing precision

Solution Approach 1:

Solder strips are removed from the second region of the solar cell, eliminating the need for soldering in that area. Current collection in the second region is achieved through the sub-busbar network alone, which is soldered to the main busbars in the first region. This extraction of soldering requirements reduces solder strip consumption and associated costs while maintaining connection reliability through the optimized busbar design.

Inventive Principle:

Principle #2Taking out (Extraction)

3Reliability

If more soldering spots are provided, then current collection is improved, but risk of micro-cracks and cold solder joints increases

Engineering Contradiction:

Improvecurrent collectionVSAvoidmicro-cracks and cold solder joints

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The design eliminates soldering spots in the second region, converting the potential harm of soldering defects into a benefit by using a solder-free sub-busbar connection method. The sub-busbars are designed to be soldered to main busbars at optimized locations, reducing the total number of soldering spots while improving current collection through the extended sub-busbar network that provides additional current pathways without requiring additional solder joints.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This design reduces the consumption of silver paste and solder strips by up to 30%, decreases the risk of soldering micro-cracks and cold solder joints, and enhances productivity by improving yield and reducing module manufacturing costs, while maintaining compatibility with various types of solar cells.

Implementation Method 1

a P-type region and an N-type region formed in a solar cell body made of a P-type semiconductor substrate

Methodology Applied

Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Implementation Method 2

a first metallization layer... a second metallization layer... the plurality of main busbars are electrically connected to the plurality of first sub-busbars

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP4141967B1Solar cell and solar cell module

Publication Date: 2023.12.06 SHANGHAI JINKO GREEN ENERGY ENTERPRISE MANAGEMENT CO LTD

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AI summary

Provided is a solar cell and a solar cell module. The solar cell includes a converging busbar. The converging busbar separates a first surface of the solar cell into a first region and a second region. The first region includes a plurality of first sub-busbars spaced along a first direction and a plurality of main busbars spaced along a second direction, and the main busbar is electrically connected to the first sub-busbar. The second region includes a plurality of second sub-busbars spaced along a third direction. The converging busbar is located between the first region and the second region, and is electrically connected to the plurality of main busbars and the plurality of second sub-busbars.