Metallic Stencil with Deformable Peripheral Zone for PV Printing

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Solution Overview

Problem

Current methods for producing electrical conductors on photovoltaic cells using screen printing face challenges such as irregular ink geometry, deformation of metal stencils due to canvas tension, and complex, expensive processes, leading to performance defects and reduced efficiency.

Innovation Solution

A screen printing system with a metallic stencil featuring a central printing zone and a peripheral deformation zone, where the peripheral zone has openings that can deform more easily than the central zone, reducing stress on the stencil and maintaining ink layer regularity, combined with a trampoline construction for elasticity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a metal stencil is used to replace canvas for screen printing, then manufacturing precision of conductor geometry is improved, but device complexity increases due to the need for trampoline construction and multiple printing steps

Engineering Contradiction:

Improveconductor geometry precisionVSAvoidprinting process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The stencil is divided into a rigid central printing zone for precise conductor patterns and a flexible peripheral zone for elastic deformation, allowing the system to achieve both precision and adaptability without complex multi-step processes

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The stencil transitions from entirely rigid metal to a composite structure with varying flexibility parameters - the central zone maintains rigidity for precision while the peripheral zone introduces controlled elasticity to accommodate trampoline construction tensions

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If canvas is glued on the periphery of metal stencil to provide elasticity, then ease of operation is improved, but manufacturing precision deteriorates due to stencil deformation under canvas tension

Engineering Contradiction:

Improvestencil elasticityVSAvoidconductor pattern accuracy

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

Different zones of the stencil have different mechanical properties - the central printing zone is made rigid for precision while the peripheral zone is made flexible to absorb tension, allowing the system to have both elasticity and precision simultaneously in different locations

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The stencil is segmented into rigid and flexible zones, with the flexible peripheral zone specifically designed to deform under canvas tension while the rigid central zone remains stable for precise printing

Inventive Principle:

Principle #1Segmentation

3Productivity

If openings of large surface are made in metal stencil, then productivity is improved by reducing number of printing steps, but strength of stencil deteriorates

Engineering Contradiction:

Improveprinting efficiencyVSAvoidstencil structural integrity

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

The peripheral zone has larger openings and lower structural strength specifically where high deformation is needed, while the central zone maintains sufficient strength to support large-area openings for high-productivity single-step printing

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 solution enhances the productivity, performance, and economy of photovoltaic cell conductor production by minimizing stencil deformation and ensuring precise ink deposition, resulting in improved electrical performance and reduced defects.

Implementation Method 1

a metallic stencil (12) comprising a central printing zone (13) and a peripheral deformation zone (14), said peripheral deformation zone making it possible to induce a voluntary and preferential deformation of said stencil under the effect of the tension induced by the canvas (15)

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Implementation Method 2

associated with a canvas glued on the periphery to give the whole a sufficient elasticity, according to a construction called 'trampoline'

Methodology Applied

Scientific EffectTension: Tension

Implementation Method 3

This crossing is obtained with the help of a doctor blade which presses the ink through the canvas

Methodology Applied

Scientific EffectMechanical pressure: Pressure Increase

Data Source

PatentEP2691237B1Silk-screen stencil for printing onto a photovoltaic cell

Publication Date: 2015.04.22 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES

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AI summary

The invention relates to a stencil for a silk-screen printing system, including grooves (22) provided in a central printing area (13) and representing a design to be printed, characterized in that it includes opening(s) (32) in a peripheral deformation area (14), having a surface inducing a property of greater deformation of the peripheral deformation area (14) than of the central printing area (13), and intended to induce deformations of said peripheral deformation area (14) by means of tension applied to the stencil while reducing the deformation of the central printing area (13).