Cap Assembly Safety Vent with Shape-Memory Alloy Lifting Guide
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Solution Overview
Problem
Secondary batteries lack an effective mechanism to release gas and heat when internal pressure is low, potentially leading to accidents such as explosions due to unopened safety vents.
Innovation Solution
A cap assembly with a safety vent and a shape-memory alloy lifting guide part that expands to open the vent and release gas or heat, even at low pressure, by cutting a predetermined weak part, ensuring safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a safety vent is designed to open only when gas pressure increases, then the safety vent structure is simple, but the safety vent will not open when temperature increases at low pressure, causing potential accidents
Solution Approach 1:
The safety vent is divided into multiple independent opening mechanisms: a pressure-responsive opening mechanism and a temperature-responsive opening mechanism. The lifting guide part is segmented into multiple sections that can be independently activated by either pressure or temperature changes, allowing the safety vent to open through different pathways depending on the specific hazard condition.
Solution Approach 2:
The lifting guide part acts as an intermediary component that translates both pressure changes and temperature changes into mechanical motion to open the safety vent. This intermediary mechanism converts thermal expansion and pressure-driven displacement into the lifting motion required to open the vent, unified the response to different hazard types.
2Reliability
If a lifting guide part made of shape-memory alloy is used to open the safety vent through thermal expansion, then the safety vent can open at low pressure, but the device complexity increases
Solution Approach 1:
The lifting guide part utilizes shape-memory alloy material that changes its physical parameters (shape and size) in response to temperature changes. When the battery overheats, the alloy expands or changes shape, which mechanically lifts the safety vent to open it. This parameter change approach allows the system to respond to temperature increases without requiring complex sensing or actuation mechanisms.
Solution Approach 2:
The lifting guide part made of shape-memory alloy is a self-actuating component that automatically responds to temperature changes without external control. The material's inherent thermal response properties enable it to autonomously lift the safety vent when heated, eliminating the need for separate sensors, actuators, or control systems.
3Productivity
If multiple lifting guide parts are provided to open multiple portions of the safety vent, then the gas and heat release speed increases, but the manufacturing complexity increases
Solution Approach 1:
The lifting guide part is divided into multiple identical or similar segments arranged around the safety vent. Each segment independently contributes to opening a portion of the vent, allowing the system to achieve rapid and uniform venting through modular replication rather than complex integrated design.
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 cap assembly quickly releases gas and heat, preventing accidents by utilizing the shape-memory alloy lifting guide to open the safety vent, enhancing safety without external control.
Implementation Method 1
a lifting guide part disposed between the safety vent and the down cap to lift the safety vent while being expanded by a high-temperature gas transferred from the inside of the can
Implementation Method 2
The lifting guide part may be made of a shape-memory alloy material that is restored in a circular shape after being expanded according to a temperature
Data Source
AI summary
The present invention provides a cap assembly mounted on an opening of a can, the cap assembly comprising: a top cap; a safety element disposed on a lower portion of the top cap; a safety vent disposed on a lower portion of the safety element and having a cut part; a down cap disposed on a lower portion of the safety vent; a gasket surrounding edges of the top cap, the safety element, the safety vent, and the down cap and mounted on the opening of the can; and a lifting guide part disposed between the safety vent and the down cap to lift the safety vent while being expanded by a high-temperature gas transferred from the inside of the can and thereby to cut the cut part so that the high-temperature gas is released to the outside.