Battery Overcharge Protection Assembly Spiral Vent Disk
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Solution Overview
Problem
Lithium-ion battery cells are susceptible to thermal runaway due to overheating and overpressurization during overcharge events, which can render the battery module inoperable and propagate unstable conditions to adjacent cells.
Innovation Solution
An overcharge protection assembly featuring a spiral disk and vent disk that interrupts current flow when internal pressure increases, breaking along a vent groove to prevent further charging and reduce thermal runaway risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional axial displacement interruption mechanisms are used, then current flow can be interrupted under normal conditions, but they fail to effectively prevent thermal runaway during overcharge events caused by overheating and overpressurization
Solution Approach 1:
The protection assembly is divided into distinct functional components: a spiral disk with radial slots that can rotate independently, a vent disk with a vent groove, and a current collector. This segmentation allows each component to perform its specific function (current conduction, pressure sensing, current interruption) while working together to provide comprehensive overcharge protection that addresses both thermal and pressure-related thermal runaway risks
Solution Approach 2:
The spiral disk is designed to rotate dynamically in response to internal pressure changes rather than relying on static axial displacement. When internal pressure increases during overcharge, the spiral disk rotates about its central axis, which triggers the vent disk to break along the vent groove and interrupt current flow. This dynamic response mechanism effectively detects and responds to overcharge conditions caused by both overheating and overpressurization
2Productivity
If the battery cell allows continuous charging to maximize energy storage, then productivity increases, but thermal runaway may occur due to overheating and overpressurization
Solution Approach 1:
The protection assembly implements a feedback mechanism where the spiral disk continuously monitors internal pressure conditions through its rotation capability. When overcharge causes internal pressure to increase, the spiral disk rotates and triggers the vent disk to break, interrupting current flow. This automatic feedback loop allows the battery to operate at high charging capacities while providing real-time protection against thermal runaway conditions
Solution Approach 2:
The vent disk is pre-configured with a vent groove in a specific location, and the spiral disk is positioned to rotate into contact with the vent disk at a predetermined angle. This preliminary arrangement ensures that when overcharge occurs, the current interruption happens automatically at the optimal moment before thermal runaway can develop, allowing maximum safe charging capacity while preventing catastrophic failure
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
Effectively prevents thermal runaway and unstable conditions in battery cells during overcharge events, protecting both individual cells and adjacent modules from damage.
Implementation Method 1
when an internal pressure of the battery cell reaches a threshold value... Over pressurization of the battery cell may create unstable conditions
Implementation Method 2
the vent disk may break along a vent groove in the vent disk... causing the spiral disk to rotate
Implementation Method 3
pressure from the battery cell may push the vent disk upward and cause the spiral disk to rotate
Data Source
Figure 1
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Figure 4
AI summary
A battery module includes plurality of prismatic battery cells. Each prismatic battery cell includes a casing housing electrochemically active components and a cover assembly. The cover assembly includes a cover, a terminal(96) protruding through the cover, a current collector electrically coupled to the terminal, and an overcharge protection assembly between the terminal and current collector. The overcharge protection assembly includes a spiral disk (120) and a vent disk (117) physically and electrically coupled, wherein the vent disk is between the spiral disk and the terminal and includes a concave structure forming a cavity between the vent disk and the terminal. The vent disk is configured to deform into the cavity and break when a pressure within the casing exceeds a threshold value. The spiral disk is configured to apply a shearing force to the vent disk when the vent disk deforms to facilitate the breakage to interrupt electrical current flow.