Battery Top Cap With Shape Memory Thermal Current Cutoff
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Solution Overview
Problem
Conventional cylindrical secondary batteries face safety issues due to internal short circuits during charging and discharging, leading to gas generation and potential explosion or rupture, necessitating improved structural safety measures.
Innovation Solution
Incorporation of a top cap with a shape memory alloy-based electricity cut-off portion that disconnects the supply and terminal portions at high temperatures, utilizing an insulator and deformation body to rapidly cut off current flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional cap assembly with safety vent and CID is used, then gas discharge and current cutoff functions are provided, but rapid current cutoff at high temperature is not achieved
Solution Approach 1:
The patent changes the physical state parameter of the shape memory alloy by setting its transformation temperature (70°C or higher) to match the high-temperature condition during thermal runaway. When the temperature reaches this parameter threshold, the alloy automatically transforms from austenite to martensite phase, causing rapid contraction that disconnects the electrical connection within seconds, achieving both high reliability and fast response speed
Solution Approach 2:
The patent replaces the conventional mechanical CID system with a thermally-responsive shape memory alloy system. Instead of relying on mechanical pressure or thermal expansion mechanisms, the invention uses the phase transformation properties of the shape memory alloy to directly contract and cut off current when temperature reaches 70°C or higher, achieving rapid electrical disconnection without complex mechanical structures
2Speed
If the deformation body is made of shape memory alloy, then rapid deformation and current cutoff are achieved, but device complexity increases
Solution Approach 1:
The patent extracts only the essential functional component (shape memory alloy deformation body) needed for rapid response, eliminating unnecessary mechanical structures found in conventional CID systems. By using the intrinsic phase transformation properties of the shape memory alloy, the invention achieves rapid deformation without adding complex control mechanisms, actuators, or multi-component assemblies
Solution Approach 2:
The shape memory alloy deformation body is designed to automatically respond to temperature changes without external control. When the temperature reaches 70°C or higher, the alloy self-transforms from austenite to martensite phase and automatically contracts to disconnect the electrical connection, eliminating the need for external sensors, controllers, or power sources that would increase device complexity
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 prevents electricity transmission when high temperatures occur, enhancing safety by rapidly disconnecting the supply and terminal portions, thus preventing further heat buildup and potential explosions.
Implementation Method 1
the deformation body may be made of a shape memory alloy that contracts above the deformation temperature
Data Source
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AI summary
A top cap of the present disclosure includes a supply portion that supplies electricity to an external circuit; a terminal portion that supplies electricity to the supply portion; and an electricity cut-off portion that electrically connects the supply portion and the terminal portion or disconnects them so as not to conduct electricity depending on the deformation temperature, wherein the electricity cut-off portion includes an insulator provided between the supply portion and the terminal portion and allowing the supply portion and the terminal portion to be spaced apart so as not to contact each other; and a deformation body that electrically connects the supply portion and the terminal portion below the deformation temperature and is deformed above the deformation temperature to disconnect the supply portion and the terminal portion so as not to conduct electricity.