Patterned Back-Sheet Conductive Patches for Solar Cell Interconnection

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Solution Overview

Problem

The high cost and poor interconnection properties of copper-based conductive layers in solar panels, particularly with aluminum, lead to increased production costs and unreliable electrical connections due to the cumbersome soldering process and high contact resistance.

Innovation Solution

A solar panel design featuring a patterned conductor circuit layer with local patches of a second conductive material, such as copper, tin, or nickel, applied using cold spraying or other methods like ultrasonic bonding or chemical plating, to improve electrical and mechanical adhesion at specific contact points, reducing the overall use of costly metals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a copper-based conductive layer is used, then good interconnection properties and reliable electrical connections are achieved, but production costs increase significantly

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies local quality by using copper patches only at specific contacting areas where electrical connections are needed, rather than covering the entire back sheet. This localized application of expensive material (copper) on an aluminum substrate provides good interconnection properties exactly where required while minimizing overall material costs.

Inventive Principle:
Principle #3Local quality

2Quantity of substance

If an aluminum-based conductive layer is used, then production costs are reduced, but interconnection properties and soldering performance deteriorate

Engineering Contradiction:
Improveproduction costVSAvoidinterconnection property
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent employs composite materials by combining aluminum and copper in a layered structure. The aluminum layer provides cost-effective coverage over most of the back sheet surface, while copper patches are integrated at specific contacting areas to provide excellent soldering performance and electrical interconnection properties. This composite approach optimizes both cost and performance.

Inventive Principle:
Principle #40Composite materials

3Reliability

If vacuum deposition or cladding techniques are used to improve aluminum conductive layer properties, then interconnection performance improves, but manufacturing time and cost increase

Engineering Contradiction:
Improveinterconnection propertyVSAvoidmanufacturing efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies segmentation by dividing the conductive layer into distinct aluminum and copper regions. Instead of applying expensive vacuum deposition or cladding techniques to the entire surface, the copper layer is segmented into discrete patches only at contacting areas. This segmentation reduces manufacturing complexity and time while maintaining good interconnection properties where needed.

Inventive Principle:
Principle #1Segmentation

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 approach enhances the interconnection properties and reduces production costs by using less expensive materials effectively, while simplifying the manufacturing process and improving the reliability of electrical connections.

Implementation Method 1

A solar panel design featuring a patterned conductor circuit layer with local patches of a second conductive material, such as copper, tin, or nickel, applied using cold spraying or other methods like ultrasonic bonding or chemical plating

Methodology Applied
Scientific EffectCold spraying:

Implementation Method 2

A solar panel design featuring a patterned conductor circuit layer with local patches of a second conductive material, such as copper, tin, or nickel, applied using cold spraying or other methods like ultrasonic bonding or chemical plating

Methodology Applied
Scientific EffectUltrasonic bonding: Ultrasonic Vibration

Implementation Method 3

A solar panel design featuring a patterned conductor circuit layer with local patches of a second conductive material, such as copper, tin, or nickel, applied using cold spraying or other methods like ultrasonic bonding or chemical plating

Methodology Applied
Scientific EffectChemical plating: Electroplating

Data Source

PatentEP2994941B1Solar panel and method for manufacturing such a solar panel
Publication Date: 2019.03.06 NEDERLANDSE ORG VOOR TOEGEPAST NATUURWETENSCHAPPELIJK ONDERZOEK TNO
  • EP2994941B1 patent drawingFigure 1~2a
  • EP2994941B1 patent drawingFigure 2b~3a
  • EP2994941B1 patent drawingFigure 3b~3c

AI summary

A solar panel is provided with a stack including at least one back contacted solar cell and a back-sheet layer. The back-sheet layer has a patterned conductive layer of a first material. The conductive layer is arranged with contacting areas each located at a location corresponding to a location of an electrical contact on the solar cell. The solar cell is arranged on top of the conductive layer with the rear surface of the solar cell facing the patterned conductive surface. Each electrical contact of the solar cell is in contact with a corresponding contacting area on the conductor circuit by a body of conductive connecting material. The conductive layer includes at the location of the contacting area a patch of a second material. Each patch is arranged in between the body of conductive connecting material on one electrical contact and the layer of the first material.