PTC Over-Current Protection Composite for Thin High-Voltage Devices
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Solution Overview
Problem
Small-sized over-current protection devices with low electrical resistivity face challenges in voltage endurance capability, leading to easy burnout due to reduced thickness and increased electrical resistance, which is exacerbated by the lack of effective fillers that enhance both properties.
Innovation Solution
Incorporating a titanium-containing inner filler with a perovskite structure into the PTC composite, composed of a fluorine-free polyolefin-based polymer and conductive filler, to improve voltage endurance while maintaining low electrical resistivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the thickness of the PTC material layer is reduced to make the device smaller, then the device size is decreased, but the voltage endurance capability is reduced and the device is easily burnt out
Solution Approach 1:
The patent applies composite materials by combining fluorine-free polyolefin-based polymer with perovskite structure compound as filler. This composite structure enables the PTC material layer to achieve both low electrical resistivity and high voltage endurance capability, resolving the contradiction between device miniaturization and reliability. The perovskite filler particles dispersed in the polymer matrix create a composite that maintains electrical stability under high voltage stress even in thin layers.
Solution Approach 2:
The patent changes the physical and chemical parameters of the PTC material by introducing perovskite structure compound with specific properties (high dielectric constant, stable crystal structure). This parameter change in the material composition allows the thin PTC layer to withstand high voltage stress, enabling device miniaturization without sacrificing voltage endurance capability.
2Area of stationary object
If the top-view area of the PTC material layer is decreased to make the device smaller, then the device size is reduced, but the electrical resistance increases and the voltage which the device can endure is lowered
Solution Approach 1:
The composite material consisting of fluorine-free polyolefin-based polymer and perovskite structure compound enables small-area PTC devices to maintain low electrical resistance and high voltage endurance. The perovskite filler creates conductive pathways and enhances dielectric strength, allowing the device to achieve both compact size and reliable voltage withstanding capability.
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 addition of the perovskite-based filler stabilizes the recrystallization process, enhances electric polarization, and prevents hydrofluoric acid production, resulting in devices that can withstand high voltages and maintain low electrical resistance over multiple cycles without burnout.
Implementation Method 1
The addition of the perovskite-based filler stabilizes the recrystallization process
Implementation Method 2
enhances electric polarization
Implementation Method 3
prevents hydrofluoric acid production
Implementation Method 4
The conductive filler is dispersed in the polymer matrix, thereby forming an electrically conductive path in the PTC material layer
Implementation Method 5
the electrical resistance of the PTC conductive composite material remains extremely low at normal temperatures, so that the circuit or cell can operate normally. However, when an over-current or an over-temperature event occurs in the circuit or cell, the electrical resistance will instantaneously increase to a high electrical resistance state
Data Source
AI summary
An over-current protection device comprises first and second electrode layers and a PTC material layer laminated therebetween. The PTC material layer includes a polymer matrix, a conductive filler and a titanium-containing inner filler. The polymer matrix has a fluorine-free polyolefin-based polymer. The titanium-containing inner filler has a compound represented by a general formula of MTiO3, wherein the M represents transition metal or alkaline earth metal. The total volume of the PTC material layer is calculated as 100%, and the titanium-containing inner filler accounts for 1-9% by volume of the PTC material layer.