Electronic Component External Electrode Stress Distribution
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Solution Overview
Problem
Existing electronic components face challenges in maintaining strong fixing strength between the element body and external electrodes while ensuring reliable electrical contact and managing stress generated by the sintered metal layer.
Innovation Solution
The electronic component design includes a sintered metal layer with varying thickness portions, covered by a conductive resin layer, which distributes stress and enhances connectability between internal conductors and the external electrode, improving fixing strength and maintaining electrical contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the sintered metal layer has uniform thickness throughout, then manufacturing is simple, but fixing strength at the center is insufficient and stress concentration occurs
Solution Approach 1:
The sintered metal layer is designed with different thicknesses in different regions: a first thickness in the central region, a second thickness (greater than the first) in a first peripheral region, and a third thickness (less than the first) in a second peripheral region. This local variation in thickness provides enhanced fixing strength at the center where it is most needed, while reducing stress concentration and allowing for stress relaxation in peripheral areas.
2Stress or pressure
If the conductive resin layer is applied uniformly, then manufacturing is simple, but stress from solder fillet is not effectively relaxed
Solution Approach 1:
The conductive resin layer is designed with different thicknesses in different regions corresponding to the sintered metal layer regions. The first conductive resin layer portion has a first thickness, the second conductive resin layer portion has a second thickness greater than the first, and the third conductive resin layer portion has a third thickness less than the first. This graduated thickness distribution allows the conductive resin layer to effectively absorb and relax stress from the solder fillet, particularly at the central region where stress concentration occurs during mounting.
3Strength
If the sintered metal layer thickness is increased throughout, then fixing strength is improved, but stress by the sintered metal layer increases
Solution Approach 1:
The sintered metal layer employs a non-uniform thickness distribution with a thinner central region (first thickness) and thicker peripheral regions (second and third thicknesses). This design provides sufficient fixing strength at the center while the thinner profile reduces the overall stress generated by the sintered metal layer, preventing stress-related failures.
Solution Approach 2:
The sintered metal layer is segmented into distinct regions with different thicknesses: a central region, a first peripheral region, and a second peripheral region. This segmentation allows each region to be optimized for its specific function - the central region for stress reduction and the peripheral regions for enhanced fixing strength.
4Area of stationary object
If material is used throughout the entire end surface, then coverage is complete, but material usage and cost increase
Solution Approach 1:
The sintered metal layer uses a non-uniform thickness distribution that concentrates material where it is most needed for fixing strength (peripheral regions) while using less material in the central region. This optimized material distribution achieves complete coverage and sufficient mechanical strength while minimizing overall material consumption and associated costs.
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 effectively relaxes stress from solder fillets, secures electrical connections, and reduces material usage by optimizing the thickness of the conductive resin layer, resulting in improved mounting and connectivity of the electronic component.
Implementation Method 1
the external electrode includes the conductive resin layer, and therefore the stress by the solder fillet is relaxed by the conductive resin layer
Implementation Method 2
an internal conductor disposed in the element body and connected to the external electrode
Data Source
AI summary
An external electrode includes a sintered metal layer disposed on at least an end surface and a conductive resin layer disposed on the sintered metal layer. The sintered metal layer includes a first portion, a second portion, and a third portion. The first portion is disposed at a central region of the end surface. The second portion is disposed at a part of a peripheral region of the end surface, and extends to an edge portion of the end surface from the first portion. The third portion is disposed at a remaining part of the peripheral region of the end surface. The thickness of the second portion is less than that of the first portion. The thickness of the third portion is less than that of the second portion. The first portion, the second portion, and the third portion are covered with the conductive resin layer.