Protective Device Sacrificial Metal Element Bridge Structure
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Solution Overview
Problem
Conventional protective devices for electronic devices are inadequate in effectively preventing over currents and over voltages, as they rely on temperature fuses that may not consistently disconnect the circuit to prevent explosions during charging and discharging.
Innovation Solution
A protective device with a substrate, conductive metal element, and bridge element, where the metal element has a lower melting point than the electrodes, and a bridge element that facilitates breaking upon melting, along with auxiliary media and heat-generating elements to ensure reliable disconnection and reduce the risk of short-circuiting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a temperature fuse is serially connected with a battery circuit and electrically connected to a heater and controlling units (FET, IC), then the device can achieve over voltage protection by melting the temperature fuse, but the device may not reliably disconnect the circuit to prevent battery explosions during over current or over voltage conditions
Solution Approach 1:
The invention extracts the protective function from the existing temperature fuse-heater-FET-IC system and implements it through a dedicated protective device with a metal element and bridge element structure. This separate protective mechanism ensures reliable circuit disconnection without adding complex control units to the existing system.
Solution Approach 2:
The bridge element serves as an intermediary structure that facilitates the breaking of the metal element upon melting. It mediates the transition from a melted state to a disconnected state, ensuring that the circuit is reliably opened even when the metal element melts during over current or over voltage conditions.
2Reliability
If the metal element is used as a sacrificial structure with lower melting point than electrodes, then the device can protect against over currents and over voltages, but the alignment between the bridge element and metal element must be precise to prevent short-circuiting
Solution Approach 1:
The bridge element is pre-positioned and fixedly supported on the substrate at a predetermined location. This preliminary positioning ensures that when the metal element melts, it will be guided to the bridge element, reducing the need for high alignment precision during assembly and manufacturing.
Solution Approach 2:
The metal element serves its own protective function by melting under over current or over voltage conditions and automatically guiding itself to the bridge element through the predetermined structure. This self-guiding mechanism reduces the requirement for precise external alignment during manufacturing.
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 effectively cuts off the circuit by melting the metal element and guiding it to the bridge element, providing stable over voltage and over current protection while minimizing the risk of short-circuiting and alignment errors, thus enhancing the reliability of the protective device.
Implementation Method 1
The metal element serves as a sacrificial structure having a melting point lower than that of the first and second electrodes
Implementation Method 2
a heat-generating element supported by the substrate, providing heat to at least the metal element and auxiliary medium
Data Source
AI summary
A protective device including a substrate, a conductive section and a bridge element is provided. The conductive section is supported by the substrate, wherein the conductive section comprises a metal element electrically connected between first and second electrodes. The metal element serves as a sacrificial structure having a melting point lower than that of the first and second electrodes. The bridge element spans across the metal element in a direction across direction of current flow in the metal element, wherein the bridge element facilitates breaking of the metal element upon melting.