Gas Sensor Symmetrical Base Layer Design
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Solution Overview
Problem
Gas sensors with stacked detection elements sintered simultaneously often warp due to differences in sintering shrinkage between solid electrolyte layers and other layers, leading to cracking or breakage during assembly.
Innovation Solution
A gas sensor design with a symmetrical structure in the stacking direction, where the thickness of base layers is between 80% to 120% of the sensing portion's thickness, and base layers are made of the same material as each other, to evenly distribute stress and prevent warping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If simultaneous sintering of stacked layers is used to reduce manufacturing processes, then productivity is improved, but warping and cracking occur due to differential sintering shrinkage
Solution Approach 1:
The invention introduces an asymmetric thickness design where the third base layer (thickness T3) is made thicker than the first base layer (thickness T1), with T3 being 1.05 to 1.3 times T1. This asymmetric structure compensates for the differential sintering shrinkage between the solid electrolyte layer and other layers, balancing the overall shrinkage forces and preventing warping while maintaining the simultaneous sintering process
Solution Approach 2:
The invention changes the thickness parameter of the base layers to control sintering behavior. By setting T3 = 1.05 to 1.3 × T1, the patent optimizes the thickness parameters to compensate for differential shrinkage rates during sintering, thereby preventing warping and cracking while maintaining high productivity through simultaneous sintering
2Adaptability or versatility
If base layers have different thicknesses to accommodate functional requirements, then device functionality is improved, but warping increases due to uneven stress distribution
Solution Approach 1:
The invention applies local quality by making the third base layer locally thicker than the first base layer. This localized thickness variation (T3 > T1) provides additional shrinkage compensation at the critical location where differential shrinkage occurs most, while maintaining appropriate thickness elsewhere for functional requirements
Solution Approach 2:
The thicker third base layer acts as a counterweight to balance the differential shrinkage forces. By increasing T3 relative to T1, the structure creates a counterbalancing effect that offsets the warping tendency caused by unequal shrinkage between the solid electrolyte layer and other layers
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 significantly reduces warping and cracking, improving the reliability and assembly performance of the gas sensor by ensuring even stress distribution during sintering.
Implementation Method 1
a detection element configured to vary an electromotive force or a resistance value according to the concentration of a specified component
Implementation Method 2
a detection element configured to vary an electromotive force or a resistance value according to the concentration of a specified component
Implementation Method 3
an unsintered stacked body is integrally sintered (simultaneously sintered) to obtain a gas sensor element
Implementation Method 4
the thickness of the third base layer is 1.05 to 1.3 times the thickness of the first base layer, thereby making it possible to suppress warping of the detection element
Data Source
AI summary
A gas sensor including a detection element having a stacked structure configured to detect a specified gas component contained in a gas to be detected. The detection element includes: a sensing portion including one or more solid electrolyte layers containing a first material as a main component and having a first surface and a second surface opposite the first surface; a first portion stacked on the first surface and including one or more first base layers containing a second material as a main component different from the first material; and a second portion stacked on the second surface and including one or more second base layers containing the second material. A total thickness of the one or more second base layers in a stacking direction is not less than 80% but not more than 120% of a total thickness of the one or more first base layers.