Secondary Battery Inversion Plate Short-Circuit Safety Mechanism
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Solution Overview
Problem
Rechargeable batteries are prone to ignition and explosion due to excessive internal pressure caused by overheating and electrolyte decomposition, necessitating a solution to prevent pressure buildup and ensure safety.
Innovation Solution
A secondary battery design featuring an electrode assembly with a cap plate having a short-circuit hole and an inversion plate that inverts to induce a short-circuit current when internal pressure exceeds a reference level, accompanied by fuses with smaller cross-sectional areas to melt and cut off current flow in case of high-pressure events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the internal pressure of the secondary battery rises due to overheating or electrolyte decomposition, then the battery may ignite or explode, but if safety measures are added to prevent pressure buildup, the device complexity increases
Solution Approach 1:
The inversion plate automatically inverts when internal pressure rises, making contact with the terminal plate to create a short circuit that releases pressure. The fuse automatically melts when current exceeds a certain level, cutting off the circuit. These self-activating safety mechanisms prevent pressure buildup without requiring external monitoring or control systems, thus improving safety while minimizing added complexity.
Solution Approach 2:
The invention converts the harmful effect of high internal pressure into a beneficial safety mechanism. When pressure rises, it causes the inversion plate to invert and create a short circuit, which actually prevents further pressure buildup by triggering a controlled failure mode. The harmful pressure rise becomes the trigger for the safety response, transforming a dangerous condition into a protective action.
2Reliability
If a short-circuit hole and inversion plate are added to the cap plate to enable internal short circuiting, then safety against pressure buildup is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The cap plate is segmented into functional regions: a sealing portion that seals the case opening and a short-circuit hole portion with the inversion plate. The terminal plate is also segmented with distinct regions including the fuse part and contact areas. This segmentation allows each component to be optimized for its specific function while maintaining overall manufacturing feasibility through modular design.
Solution Approach 2:
The inversion plate is designed to invert its shape when internal pressure rises, changing from a convex shape to a concave shape. This inversion motion is the core mechanism that triggers the short circuit. The design exploits the pressure-induced shape change to activate the safety function, using the harmful pressure rise as the trigger for the protective action.
3Reliability
If fuses with smaller cross-sectional areas are used to enable current cutoff, then safety against external short circuits is improved, but the strength of the terminal plate decreases
Solution Approach 1:
The terminal plate exhibits local quality variation through its segmented design. The fuse part has a smaller cross-sectional area to facilitate current cutoff and melting under fault conditions, while other regions of the terminal plate maintain larger cross-sectional areas to provide structural strength. This localized variation in geometry allows the plate to simultaneously achieve safety functionality and mechanical strength where needed.
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 prevents excessive internal pressure rise by initiating an internal short circuit and stabilizes against external short circuits, thereby preventing ignition or explosion, ensuring safer operation.
Implementation Method 1
When an internal pressure of the case is greater than a reference pressure, the inversion plate may be inverted and make contact with the first terminal plate to induce a short-circuit current
Implementation Method 2
a fuse part comprising a first fuse and a second fuse spaced apart from each other in the first terminal plate
Data Source
AI summary
A secondary battery includes an electrode assembly including a first electrode plate, a second electrode plate and a separator between the first electrode plate and the second electrode plate; a case accommodating the electrode assembly and having an opening; a cap plate sealing the opening of the case, the cap plate electrically connected to the second electrode plate and having a short-circuit hole; an inversion plate arranged in the short-circuit hole; a first terminal plate electrically connected to the first electrode plate and spaced apart from the cap plate; and a fuse part comprising a first fuse and a second fuse spaced apart from each other in the first terminal plate.