Secondary Battery Cap Assembly Deformable Plate Safety
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Solution Overview
Problem
The miniaturization and weight reduction of secondary batteries are limited by safety concerns due to the use of highly reactive materials like lithium, necessitating innovative designs that enhance safety while maintaining performance.
Innovation Solution
A secondary battery design featuring a cap assembly with a deformable plate and cover that creates a negative pressure space, preventing air circulation and potential short-circuits by deforming when internal pressure exceeds a set threshold, thereby enhancing safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If secondary batteries use highly reactive materials like lithium to achieve high energy density, then power output and energy storage are improved, but safety concerns worsen due to risk of explosions and short-circuits
Solution Approach 1:
The patent applies preliminary action by pre-configuring a deformable plate positioned between the electrode assembly and cap plate that will automatically deform to close the short-circuit opening when internal pressure exceeds a predetermined threshold. This pre-positioned safety mechanism activates before catastrophic failure can occur, preventing explosions and short-circuits while maintaining the high energy density benefits of lithium-based materials.
Solution Approach 2:
The deformable plate serves as an intermediary element between the electrode assembly and cap plate. It mediates the pressure buildup by deforming to close the short-circuit opening, thereby protecting the highly reactive lithium materials from direct exposure to external air while still allowing the battery to maintain its high power output capabilities.
2Weight of moving object
If secondary batteries are miniaturized and reduced in weight to meet portable device requirements, then device portability is improved, but safety margins worsen due to reduced space for protective structures
Solution Approach 1:
The patent employs a deformable plate that functions as a flexible safety component. This thin, flexible structure can be integrated into miniaturized battery designs without adding significant weight or volume, yet it provides effective safety protection by automatically closing the short-circuit opening when pressure exceeds safe thresholds.
Solution Approach 2:
The deformable plate transitions from a static structural element to a dynamic safety mechanism that responds to pressure changes. This dynamic response allows the safety system to activate only when necessary, maintaining the lightweight and compact design while providing adequate safety margins even in miniaturized batteries.
3Reliability
If a deformable plate is added to create a negative pressure space for safety, then safety is improved by preventing air circulation, but device complexity worsens due to additional components
Solution Approach 1:
The deformable plate performs multiple functions: it serves as part of the battery's structural assembly, creates the negative pressure space when deformed, closes the short-circuit opening to prevent air circulation, and activates automatically based on pressure thresholds. This multi-functionality improves safety without proportionally increasing device complexity.
Solution Approach 2:
The deformable plate is designed to automatically deform and close the short-circuit opening when internal pressure exceeds the predetermined threshold, without requiring external control systems or additional sensors. This self-service mechanism improves safety while minimizing the increase in 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 design effectively manages internal pressure and prevents air circulation, reducing the risk of explosions and enhancing safety while allowing for potential size and weight reduction of secondary batteries.
Implementation Method 1
The first deformable plate may be configured to deform when an internal pressure of the secondary battery exceeds a set pressure
Implementation Method 2
A space defined between the cover and the first deformable plate may have a negative pressure
Data Source
AI summary
A secondary battery having improved safety includes an electrode assembly, a case configured to accommodate the electrode assembly, and a cap assembly coupled to the case. The cap assembly includes a cap plate configured to cover the case and defining a short-circuit opening therein, a short-circuit plate exterior to the cap plate and positioned such that at least a portion of the short-circuit plate is positioned in the short-circuit opening, a first deformable plate inside the cap plate, and a cover exterior to the short-circuit plate extending over the short-circuit plate. A space defined between the cover and the first deformable plate has a negative pressure.