Back-Contact PV Cell Interconnection via Insulated Conductive Threads

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Solution Overview

Problem

Existing methods for electrically connecting contact areas of photovoltaic cells, particularly back-contact cells, are inflexible and require multiple process steps, often necessitating insulating layers that can lead to contamination and shadowing losses, and lack the ability to easily adapt to different cell designs.

Innovation Solution

A method using an electrical connector with an electrically conductive core and an insulating enveloping part, where the insulating threads wrap around the core, leaving it partially uncovered, allowing for flexible positioning and connection by bridging gaps with conductive material, eliminating the need for pre-made openings and insulating layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an insulating layer is provided on the rear surface of the cell with openings at contact areas, then electrical insulation is achieved to prevent short-circuiting, but the process complexity increases and flexibility decreases

Engineering Contradiction:
Improveelectrical insulationVSAvoidprocess steps
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the insulating function from a separate insulating layer and integrates it into the connector itself through the insulating coating on the conductive core. This eliminates the need for a dedicated insulating layer on the cell surface, reducing process steps while maintaining electrical insulation reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The connector is designed to perform multiple functions simultaneously: it provides electrical connection through the conductive core and electrical insulation through the insulating coating. This multi-functionality eliminates the need for separate insulating components and reduces overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of manufacture

If pre-made openings are provided in the insulating material according to terminal region spacing, then electrical connection is simplified, but adaptability to different cell designs is reduced

Engineering Contradiction:
Improveconnection processVSAvoidflexibility for different cell designs
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent makes the connector adaptable to different cell designs by allowing the spacing and positioning of uncovered conductive core sections to be adjusted according to the specific terminal region configuration. This dynamic adaptability enables the same connector design to work with various cell types without requiring pre-configured openings.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The insulating coating is applied selectively, leaving certain sections of the conductive core uncovered at specific locations corresponding to contact areas. This local variation in insulation provides both electrical insulation where needed and electrical connection where required, while maintaining adaptability to different cell designs.

Inventive Principle:
Principle #3Local quality

3Reliability

If metal connectors are soldered to contact areas to extract current, then electrical connection is established, but shadowing losses occur on the cell surface

Engineering Contradiction:
Improveelectrical connectionVSAvoidshadowing losses
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent uses a thin insulating coating on the conductive core that allows the connector to make contact with the contact areas without requiring large metal surfaces. This minimizes the shadowing effect while maintaining reliable electrical connection through the conductive core at the uncovered sections.

Inventive Principle:
Principle #30Flexible shells and thin films

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 reduces process steps, enhances flexibility in accommodating different cell designs, prevents short-circuits, and allows for efficient electrical connection without the need for insulating layers, enabling the same connector to be used across various cell configurations.

Implementation Method 1

By melting the electrically conductive material at selected locations, the electrically conductive material may flow through mesh openings of the electrically insulating woven material to contact the plurality of contact areas

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

positioning on a surface of the photovoltaic cell an electrically insulating woven material. An electrically conductive material is provided over the electrically insulating woven material

Methodology Applied
Scientific EffectElectrical insulation: Electrical Resistance

Implementation Method 3

By melting the electrically conductive material at selected locations

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP3235012B1Method for interconnecting back-contact photovoltaic cells
Publication Date: 2022.01.26 INTERUNIVERSITAIR MICRO ELECTRONICS CENT (IMEC VZW)
  • EP3235012B1 patent drawingFigure 1
  • EP3235012B1 patent drawingFigure 2
  • EP3235012B1 patent drawingFigure 3

AI summary

A method is provided for electrically connecting a plurality of contact areas located on a surface of a photovoltaic cell, the method comprising: positioning on the surface of the photovoltaic cell an electrical connector, thereby covering the plurality of contact areas with the electrical connector, and electrically connecting the electrical connector to the plurality of contact areas, wherein the electrical connector comprises an electrically conductive core and an electrically insulating enveloping part, the enveloping part comprising electrically insulating threads enveloping the electrically conductive core and leaving the electrically conductive core partially uncovered. The electrical connection may for example be established by soldering or by means of a conductive adhesive. A method is provided for electrically connecting back-contact cells within a photovoltaic module using such electrical connectors.