Gas Sensor Element Insulating Layer Overlap Design
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Solution Overview
Problem
In gas sensor elements, the overlap of rear end portions of electrodes and front end portions of leads on the solid electrolyte layer leads to reduced gas diffusion, causing the sensor to become brittle and deteriorate, resulting in decreased detection accuracy.
Innovation Solution
Designing gas sensor elements with leads denser than electrodes, where the rear end portions of electrodes are located on insulating layers overlapping the front end portions of leads, preventing direct contact and allowing for better gas diffusion while maintaining reliable electrical connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rear end portions of electrodes and front end portions of leads overlap on the solid electrolyte layer to improve electrical connection reliability, then electrical connection reliability is improved, but gas diffusion is reduced causing the sensor element to become brittle and cracks to occur
Solution Approach 1:
An insulating layer is introduced as an intermediary between the lead and the solid electrolyte layer in the overlap portion. This insulating layer prevents direct contact between the lead and solid electrolyte, allowing exhaust gas to diffuse through the overlap portion to the electrode while maintaining electrical connection reliability through the electrode-lead overlap structure.
2Reliability
If leads are made dense to reduce electrical resistance for signal transmission, then electrical conductivity is improved, but gas diffusion to the overlap portion is blocked
Solution Approach 1:
The lead is segmented into two distinct portions: a front portion that is porous to allow gas diffusion through the overlap region, and a rear portion that is dense to provide low electrical resistance for signal transmission. This segmentation allows the lead to simultaneously fulfill both gas permeation and electrical conduction functions.
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 configuration enhances the durability of the sensor element by preventing brittleness and cracking, while ensuring accurate gas detection and efficient signal transmission.
Implementation Method 1
a plate-shaped solid electrolyte layer extending in a longitudinal direction thereof; a pair of sensor electrodes arranged on a front side of the solid electrolyte layer
Implementation Method 2
it is necessary that each of the electrodes have a porous structure so as to take in and allow diffusion of the exhaust gas
Data Source
AI summary
There is provided a gas sensor element, including a solid electrolyte layer, a pair of sensor electrodes arranged on a front side of the solid electrolyte layer, a pair of sensor leads arranged on a rear side of the solid electrolyte layer and connected to the respective sensor electrodes; and insulating layers, one of which is arranged between one of the sensor leads and the solid electrolyte layer and the other of which is arranged between the other sensor lead and the solid electrolyte layer. The sensor electrodes have rear end portions located on the insulating layers and overlapping front end portions of the sensor leads, respectively. The sensor leads are denser than the sensor electrodes and have front ends located in the same positions as or positions rear of front ends of the insulating layers, respectively. There is also provided a gas sensor with such a gas sensor element.