Multi-Stage Safety Valve for Secondary Battery Pressure Management
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Solution Overview
Problem
Conventional secondary battery safety valves rupture immediately at a predetermined pressure level, compromising the air-tightness and reducing the cycle-life of high capacity batteries, especially in hybrid electric vehicles, due to external air and water ingress.
Innovation Solution
A multi-stage safety valve system with inner and final pressure plates that open at different pressure levels, maintaining air-tightness by allowing pressure reduction in stages before gas release, preventing battery explosion and extending cycle-life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional pressure releasing valve is used to prevent battery explosion, then safety is improved, but the battery air-tightness is compromised and cycle-life is reduced
Solution Approach 1:
The safety valve is divided into multiple pressure plates (first, second, third pressure plates) with different rupture pressure thresholds. This segmentation allows the valve to release pressure in staged increments rather than all at once, maintaining air-tightness longer while still preventing explosion. Each pressure plate segment handles a specific pressure level, creating a progressive safety mechanism that extends battery cycle-life.
2Stress or pressure
If a pressure releasing valve ruptures at predetermined pressure level, then inner pressure is reduced, but external air and water flow into the battery causing damage
Solution Approach 1:
The first pressure plate is designed to rupture at a lower pressure threshold before the main body reaches critical pressure levels. This preliminary action creates a pressure relief pathway that prevents the buildup of dangerous pressure while maintaining the integrity of the main sealing structure. The preliminary rupture of the first pressure plate allows controlled pressure release without compromising the overall air-tightness of the battery housing.
3Device complexity
If a single pressure valve is used, then device complexity is low, but the battery cannot maintain air-tightness after pressure release
Solution Approach 1:
Multiple pressure plates are nested within the cap assembly structure, with each plate contained within the same housing. The first, second, and third pressure plates are arranged in a nested configuration where they share common mounting structures and sealing pathways. This nesting approach allows multiple safety mechanisms to coexist within a compact form factor, maintaining air-tightness through the gasket while providing staged pressure release capabilities.
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 multi-stage safety valve effectively lowers inner pressure in multiple stages, reducing the risk of explosion and maintaining battery integrity, thereby enhancing the cycle-life and safety of high capacity secondary batteries.
Implementation Method 1
a first pressure plate spaced from the cap plate, and adapted to open at a predetermined inner pressure level of the battery... a second pressure plate spaced from the cap plate, and adapted to open at a predetermined inner pressure level of the battery
Data Source
AI summary
A secondary battery with a maximized cycle-life having a multi-stage safety valve so as to lower the inner pressure of the battery in stages. The multi-stage safety valve is installed on a case and the secondary battery is equipped with an electrode assembly including both positive and negative electrodes and a separator interposed therebetween.