Continuous Photovoltaic Cell Stringing With Folded Foil Interconnects

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Solution Overview

Problem

Current methods for photovoltaic cell stringing are slow, complex, and expensive, making them inefficient for mass production with a high risk of defects.

Innovation Solution

A method involving a continuous process where a foil with electrically conductive wires is folded to create slits, allowing for efficient electrical connections between photovoltaic cells, using a cam wheel and hot rollers to attach and interrupt the wires, ensuring reliable and cost-effective stringing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate processes are used for fabricating the collector-connector and performing cell stringing, then electrical connections can be established, but the fabrication method becomes slow, complex, and expensive

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidfabrication speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent combines the fabrication of the collector-connector and the cell stringing process into a single integrated continuous process. The foil with pre-applied conductive elements is fed through the system, cells are placed on it, and the foil is folded back to create electrical connections all in one continuous operation, eliminating the need for separate fabrication and assembly steps.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements a continuous manufacturing process where the foil is fed continuously through the system, cells are placed on the moving foil, and the folding and sealing operations occur continuously as the foil moves through the folding units and heating zones, eliminating stop-start operations and improving overall production efficiency.

Inventive Principle:
Principle #20Continuity of useful action

2Reliability

If traditional photovoltaic cell stringing methods are used, then electrical connections are established, but the process becomes complex and error-prone

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidprocess complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The conductive elements are pre-applied to the foil in a controlled manner before the cell placement process. The foil is prepared with the appropriate conductive pattern and structure in advance, so that when cells are placed on it, the electrical connections are already positioned and ready, simplifying the overall process and reducing errors.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The foil acts as an intermediary carrier that integrates both the electrical connection function and the mechanical support function. It serves as the medium through which conductive elements are transferred to cells, and through which the folding action creates reliable electrical connections, simplifying the overall system architecture.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If conventional cell stringing methods are used, then photovoltaic cells are connected, but the manufacturing cost increases

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the physical state of the foil material through controlled heating during the folding process. The foil is heated to a temperature where it becomes pliable and can be folded back onto itself, creating permanent creases and secure electrical connections. This parameter change enables a simpler, more cost-effective process compared to traditional mechanical fastening or soldering methods.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The foil material itself provides the electrical conductivity and the mechanical bonding function. The conductive elements on the foil create electrical connections between cells, and the folding action of the foil itself creates the mechanical attachment, eliminating the need for separate fasteners, adhesives, or soldering operations.

Inventive Principle:
Principle #25Self-service

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 method enables fast, simple, and cost-efficient production of photovoltaic cell strings with reduced error, allowing for the creation of 'endless' strings that can be customized in length and accommodating different types of photovoltaic cells.

Implementation Method 1

a heating unit that heats the foil to a temperature where the material becomes pliable

Methodology Applied
Scientific EffectThermal heating: Heating

Implementation Method 2

at least one electrically conductive wire near a first surface of the foil

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP4325585A1Method for continuous photovoltaic cell stringing and photovoltaic cell assembly
Publication Date: 2024.02.21 INTERUNIVERSITAIR MICRO ELECTRONICS CENT (IMEC VZW)
  • EP4325585A1 patent drawingFigure 1
  • EP4325585A1 patent drawingFigure 2~3
  • EP4325585A1 patent drawingFigure 4~5

AI summary

A method for continuous photovoltaic cell stringing is provided. Said method comprises the steps of providing a foil (1) in a provision direction in a continuous manner, cutting at least one slit (2) into the foil (1) along the provision direction and creating at least one slit (2) opening by folding open the foil at the location of the at least one slit. It also comprises providing at least one electrically conductive wire (3) near a first surface of the foil (1) along the provision direction aligned with the at least one slit (2) opening in a continuous manner and folding back the foil (1) at the at least one slit (2) opening after the electrically conductive wire provision such that the at least one electrically conductive wire changes its position from the first surface to a second surface being opposite to the first surface of the foil (1) in the region of the at least one slit opening, thereby closing the at least one slit opening while maintaining the at least one slit (2).