Varistor with Low-Temperature Sintering and Sacrificial Polymer
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Solution Overview
Problem
Conventional varistors face catastrophic failure when exceeding absolute maximum ratings, leading to degradation and damage from transient voltage pulses, and existing methods do not effectively address the need for improved surge protection with controlled sintering processes.
Innovation Solution
A varistor device is created using a sinterable mass with a sinter temperature below 1000 degrees Celsius, incorporating inner electrodes with a melting point within a controlled temperature range, allowing for co-firing and forming a nano-structured varistor with enhanced grain boundary layers and additives to manage thermal profiles and electrical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional varistors are used to protect against transient voltages, then surge protection is provided, but catastrophic failure occurs when absolute maximum ratings are exceeded
Solution Approach 1:
The patent applies beforehand cushioning by incorporating a sacrificial polymer layer between the varistor and the circuit board. This polymer layer is designed to fail first under excessive transient voltage conditions, absorbing the energy and preventing catastrophic failure of the varistor itself. The polymer acts as a predetermined weak point that protects the more valuable components.
Solution Approach 2:
The patent uses an intermediary approach by introducing a polymer material as a mediator between the varistor and the circuit board. This polymer layer serves as a protective interface that can withstand or absorb extreme conditions, thereby protecting the varistor from direct exposure to damaging transient voltages that would otherwise cause catastrophic failure.
2Reliability
If high sintering temperatures are used to create traditional varistors, then electrical properties are achieved, but thermal damage and structural degradation occur
Solution Approach 1:
The patent applies parameter changes by modifying the sintering temperature parameter from conventional high temperatures (typically above 1000°C) to a lower temperature range (below 1000°C). This temperature reduction is achieved through compositional modifications to the ceramic material, allowing the varistor to achieve its required electrical properties at reduced thermal conditions, thereby preventing thermal damage and structural degradation.
Solution Approach 2:
The patent employs composite materials by combining ceramic varistor materials with polymer components in a multi-layer construction. This composite structure allows the ceramic portion to provide electrical surge protection functionality while the polymer layers provide thermal management and mechanical support, enabling the system to operate reliably at lower sintering temperatures.
3Reliability
If transient voltage pulses exceed varistor ratings, then surge protection activates, but varistor degradation and damage occur
Solution Approach 1:
The patent implements beforehand cushioning by designing a polymer sacrificial layer that is positioned to absorb or divert excessive transient voltage energy before it can damage the varistor. This predetermined protective structure extends the varistor's service life by preventing degradation from extreme voltage events.
Solution Approach 2:
The patent applies the disposable principle by using a sacrificial polymer layer that is designed to fail or degrade before the varistor itself. This inexpensive polymer component acts as a disposable protective element that absorbs the damage from transient voltage spikes, thereby preserving the more valuable and longer-lasting varistor.
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
The solution provides improved surge protection by maintaining structural integrity and electrical performance, with enhanced breakdown strength and non-linearity, while reducing the risk of thermal damage during the sintering process, resulting in a more reliable and efficient varistor device.
Implementation Method 1
sintering a sinterable mass at a temperature profile that is sufficiently high such that a sintered mass may be formed from the sinterable mass. The temperature profile may be less than about 1050 degrees Celsius
Implementation Method 2
The inner electrode includes a material having a melting point that is within a determined temperature range of about 10 degrees Celsius to about 200 degrees Celsius above the sintering temperature
Data Source
AI summary
An article is provided that includes a plurality of layers. Each layer includes a sinterable mass having a sinter temperature that is less than about 1000 degrees Celsius, and an inner electrode proximate to the sinterable mass. The inner electrode includes a material having a melting point that is within a determined temperature range of about 10 degrees Celsius to about 200 degrees Celsius relative to the sintering temperature. A method to make the article is also provided.