Solid Electrolyte Sensor Via Hole Phase Stabilization

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing sensor elements for detecting gas properties, such as oxygen in exhaust gases, face challenges in maintaining mechanical strength and resisting phase transformation due to hydrothermal aging, especially at high temperatures and in the presence of vibrations or impacts, which can lead to ceramic disruption.

Innovation Solution

A sensor element design featuring a solid electrolyte layer with plated-through holes, where the opening area of these holes is stabilized using a material comprising a noble metal and elements like V, Nb, Ta, Sb, Bi, Cr, Mo, or W, applied as a stabilizing paste to prevent phase transformation, combined with an insulation and conductive paste for electrical connection and insulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If via holes are introduced into the solid electrolyte layer to establish electrical connections, then electrical connectivity is improved, but mechanical strength and resistance to phase transformation deteriorate

Engineering Contradiction:
Improveelectrical connectivityVSAvoidmechanical strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent applies different material properties to different regions: the via holes are filled with conductive paste for electrical connectivity, while the opening areas are stabilized with phase-stabilizing elements to prevent local phase transformation. This local differentiation allows simultaneous optimization of electrical performance and mechanical strength.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The sensor element uses composite construction by combining the solid electrolyte layer with conductive paste in via holes and phase-stabilizing elements at opening areas. This composite approach integrates materials with complementary properties to achieve both electrical conductivity and phase stability.

Inventive Principle:
Principle #40Composite materials

2Strength

If via holes are made small in diameter to maintain mechanical strength, then mechanical integrity is improved, but ease of manufacture deteriorates

Engineering Contradiction:
Improvemechanical integrityVSAvoidease of manufacture
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent employs preliminary actions by pre-forming the solid electrolyte layer with predetermined via hole patterns before final assembly. This allows standardized manufacturing of the electrolyte substrate with optimized hole dimensions, making subsequent filling with conductive paste and application of stabilizing elements more straightforward.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If insulating layers are added to maintain electrical resistance, then electrical insulation is improved, but device complexity increases

Engineering Contradiction:
Improveelectrical insulationVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The conductive paste serves as an intermediary material that provides both electrical conductivity within via holes and electrical insulation between adjacent via holes. This single material performs multiple functions, avoiding the need for separate insulating layers and simplifying the overall structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 sensor's stability and resilience against phase transformation, maintaining high electrical resistance and mechanical integrity even at elevated temperatures, thereby ensuring reliable operation over the sensor's lifespan.

Implementation Method 1

At least one opening area of the via is stabilized against phase transformation by a stabilizing element

Methodology Applied
Scientific EffectPhase transformation stabilization:

Implementation Method 2

The solid electrolyte layer is electrically insulated from the conductive element in the via by an insulating element

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Implementation Method 3

a conductive element that establishes an electrically conductive connection from a top surface of the solid electrolyte layer to a bottom surface of the solid electrolyte layer through the via

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3129775B1Method for producing a sensor element for detecting at least one property of a measured gas in a measured gas chamber
Publication Date: 2021.11.10 ROBERT BOSCH GMBH
  • EP3129775B1 patent drawingFigure 1
  • EP3129775B1 patent drawingFigure 2~3
  • EP3129775B1 patent drawingFigure 4

AI summary

The invention relates to a sensor element (10) for detecting at least one property of a measured gas in a measured gas chamber, in particular in order to detect a proportion of a gas component in the measured gas or a temperature of the measured gas. The sensor element (10) comprises at least one solid electrolyte layer (12, 14, 16). The solid electrolyte layer (12, 14, 16) has at least one via hole (42). The sensor element (10) further comprises a conductive element (48) which produces an electrically conductive connection from an upper face (18, 32) of the solid electrolyte layer (12, 14, 16) to a lower face of the solid electrolyte layer (12, 14, 16) through the via hole (42). The solid electrolyte layer (12, 14, 16) is electrically insulated in the via hole (42) by the conductive element (48) by means of an insulating element (44). At least one opening region (50) of the via hole (42) is stabilized against phase conversions by means of a stabilizing element (52). The stabilizing element (52) is at least partly made of a material which has a noble metal and an element selected from the group consisting of: V, Nb, Ta, Sb, Bi, Cr, Mo, and W. The invention further relates to a method for producing a sensor element (10) for detecting at least one property of a measured gas in a measured gas chamber.