Multijunction Photovoltaic Module Interconnect Zone Design

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Solution Overview

Problem

Perovskite-based photovoltaic cells face mechanical stress and damage due to electrical interconnects, which can cause fractures and delamination, especially in tandem cell configurations where the interconnect material expands and contracts differently than the cell material, affecting mechanical strength and efficiency.

Innovation Solution

A photovoltaic module design featuring a multijunction cell structure with an electrically-insulating layer on one sub-cell and an electrically-conductive layer on the other, allowing for electrical connection only in zones where the weaker sub-cell is not present, thus avoiding mechanical stress and ensuring current transfer without short circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electrical interconnects are used to connect multijunction photovoltaic cells, then electrical connection between cells is achieved, but mechanical stress and damage occur to the perovskite sub-cell due to differential thermal expansion

Engineering Contradiction:

Improveelectrical connection reliabilityVSAvoidmechanical strength of perovskite sub-cell

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent divides the cell structure into distinct zones: a first zone with the perovskite sub-cell, a second zone with the silicon sub-cell, and a third zone serving as an interconnection zone where electrical connections are made. This segmentation allows the perovskite sub-cell to be isolated from mechanical stresses imposed by interconnects, while still achieving reliable electrical connection through the conductive layer in the third zone.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a conductive layer as an intermediary element that enables electrical connection without direct mechanical contact between interconnects and the fragile perovskite sub-cell. The conductive layer is deposited on the silicon sub-cell in the third zone and provides a mechanical interface for interconnects while maintaining electrical continuity, thus protecting the perovskite sub-cell from stress.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the second photovoltaic sub-cell extends over the entire area of the first sub-cell, then maximum electrical connection area is achieved, but the weaker perovskite sub-cell is exposed to maximum mechanical stress

Engineering Contradiction:

Improveelectrical connection areaVSAvoidmechanical stress on perovskite sub-cell

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by creating spatially distinct zones with different functions. The third zone is specifically designed as an interconnection zone where the conductive layer is deposited, concentrating electrical connection activities in this localized area rather than distributing them across the entire perovskite sub-cell surface. This localized approach maintains adequate electrical connection while minimizing the area of perovskite exposed to stress.

Inventive Principle:

Principle #3Local quality

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 enhances the mechanical strength and resistance of the module, reducing the risk of damage from interconnects and maintaining high conversion efficiency by isolating the weaker sub-cell from mechanical stress while ensuring effective current transfer.

Implementation Method 1

an electrically-conductive layer electrically formed on at least part of said electrically-insulating layer and in electrical connection with a surface of said second photovoltaic sub-cell, arranged therefore to conduct current produced by the multijunction cell to the surface of said zone

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

an electrically-insulating layer situated upon the first photovoltaic sub-cell in at least a part of said zone

Methodology Applied

Scientific EffectElectrical insulation: Conduction (electrical)

Implementation Method 3

a first photovoltaic sub-cell extending over a first predetermined area; a second photovoltaic sub-cell provided directly or indirectly on said first photovoltaic sub-cell and in electrical connection therewith so as to form a multijunction cell

Methodology Applied

Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Data Source

PatentUS11588124B2Photovoltaic module

Publication Date: 2023.02.21 CSEM CENTRE SUISSE D ELECTRONIQUE ET DE MICROTECHNIQUE SA

AI summary

Photovoltaic module comprising a plurality of multijunction photovoltaic cells, at least one of said multijunction photovoltaic cells comprising:a first photovoltaic sub-cell extending over a first predetermined area;a second photovoltaic sub-cell provided on said first photovoltaic sub-cell and in electrical connection therewith, said second photovoltaic sub-cell extending over a second predetermined area which is smaller than said first predetermined area so as to define at least one zone in which said first photovoltaic sub-cell is uncovered by said second photovoltaic sub-cell;an electrically-insulating layer situated upon said first photovoltaic sub-cell in at least a part of said zone; andan electrically-conductive layer situated upon at least part of said electrically-insulating layer and in electrical connection with a surface of said second photovoltaic sub-cell,wherein at least one of said multijunction photovoltaic cells is electrically connected to at least one other of said multijunction photovoltaic cells by means of at least one electrical interconnector electrically connected to said electrically-conductive layer in said zone.