Secondary Battery Pressure-Triggered Case Puncture for Gas Release
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Solution Overview
Problem
Secondary batteries face safety issues due to potential explosions caused by abnormal operations such as overheating, overcharging, or external short circuits, which can lead to rapid electron transfer and thermal runaway, resulting in explosions.
Innovation Solution
Incorporating a piezoelectric element and a punching part made of electroactive polymer (EAP) that expands the battery case to quickly discharge gases generated inside, preventing explosions by allowing gas release through punching the case.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the battery case is sealed to prevent gas leakage, then safety is improved by containing the explosion, but gas accumulation increases the risk of explosion
Solution Approach 1:
The battery case incorporates a flexible membrane structure that can expand and contract. This membrane allows the case to contain gases under normal conditions while automatically releasing them when pressure exceeds safety thresholds, thus preventing explosion without requiring complex active venting systems.
Solution Approach 2:
The invention utilizes the phase transition or structural change of the flexible membrane material in response to pressure changes. When gas pressure builds up abnormally, the membrane undergoes a structural transition from a sealed state to a ruptured or expanded state, enabling automatic gas release to prevent explosion.
2Strength
If the battery case is made rigid to maintain structural integrity, then mechanical strength is improved, but gas discharge capability deteriorates
Solution Approach 1:
The battery case is segmented into rigid structural components for overall strength and a flexible membrane section for gas discharge. This segmentation allows different parts of the case to fulfill different functions: the rigid portions maintain structural integrity while the flexible membrane portion enables automatic gas venting when pressure builds up.
Solution Approach 2:
A flexible membrane is integrated into the rigid battery case structure. This membrane maintains the case's overall rigidity while providing a compliant region that can expand and rupture to release gases under abnormal pressure conditions, thus combining structural strength with gas discharge capability.
3Use of energy by moving object
If the separator is made thin to reduce internal resistance, then electrical performance is improved, but thermal stability deteriorates leading to short circuit
Solution Approach 1:
The separator is constructed as a composite material structure that combines thin regions for low electrical resistance with thermally stable components. The composite structure maintains electrical performance while providing thermal stability to prevent shrinkage and short circuits under elevated temperature conditions.
Solution Approach 2:
The separator's physical and chemical parameters are optimized to achieve a balance between thickness and thermal stability. By carefully controlling the separator's material composition and structure, it maintains thinness for low internal resistance while incorporating heat-resistant additives or structures that prevent thermal shrinkage and electrode contact.
4Temperature
If the collector has high thermal conductivity to dissipate heat, then thermal management is improved, but manufacturing complexity increases
Solution Approach 1:
The collector's thermal conductivity parameter is optimized within a specific range to achieve effective heat dissipation without requiring complex cooling systems. By selecting materials and structures with appropriate thermal conductivity values, the battery achieves good thermal management through simple design modifications rather than complex active cooling mechanisms.
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 explosions and ensures stability by rapidly discharging gases generated during abnormal operations, thereby enhancing safety.
Implementation Method 1
a piezoelectric element disposed outside a cup part accommodating the electrode assembly in the battery case to receive a pressure when the battery case is expanded in volume, thereby supplying the power to the outside
Implementation Method 2
a punching part which has a sharp one end and of which the one end extends toward the battery case to punch the battery case when the power is applied from the piezoelectric element
Data Source
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AI summary
A secondary battery according to an embodiment of the present invention for solving the above problems includes: an electrode assembly formed by alternately stacking an electrode and a separator; a battery case configured to accommodate the electrode assembly therein; a piezoelectric element disposed outside a cup part, which is configured to accommodate the electrode assembly in the battery case, to receive a pressure when the battery case is expanded in volume, thereby supplying power to the outside; and a punching part which has sharp one end and of which the one end extends toward the battery case to punch the battery case when the power is applied from the piezoelectric element.