Battery Cell Venting Arrangement with Yieldable Element
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Solution Overview
Problem
Conventional Li-Ion battery venting mechanisms are prone to clogging due to the collapse of supporting washers, leading to potential cell rupture and safety hazards, as they fail to effectively manage excessive pressure buildup before thermal runaway occurs.
Innovation Solution
The implementation of a venting arrangement with a yieldable element supported by a spacer or composite bursting disc, featuring enhanced score lines and a large opening design, which prevents collapse and ensures reliable gas venting to ambient, thereby forestalling clogging and enhancing safety margins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional venting mechanism with a supporting washer is used, then the cell can release pressure through the terminal orifices, but the washer collapses under pressure and clogs the vent orifices, leading to cell rupture
Solution Approach 1:
The venting function is divided into two independent pathways: terminal orifices and windowing. This segmentation ensures that if one pathway becomes blocked (washer collapse), the other remains open to prevent cell rupture, thereby maintaining venting reliability while eliminating the harmful effect of complete blockage.
Solution Approach 2:
The windowing acts as an intermediary venting pathway between the cell interior and ambient environment. It provides an alternative route for pressure relief that is independent of the terminal washer assembly, preventing the harmful effect of washer collapse from leading to cell rupture.
2Strength
If the vent opening is made small to maintain terminal integrity, then the terminal structure remains strong, but the venting capacity is insufficient to handle rapid pressure buildup
Solution Approach 1:
The venting function is divided into two independent pathways: terminal orifices and windowing. This segmentation allows the terminal to maintain its structural integrity with smaller openings while the windowing provides additional venting capacity to handle rapid pressure buildup, thus resolving the contradiction between terminal strength and pressure relief rate.
Solution Approach 2:
The venting capacity is enhanced by adding windowing on the cell body surface, which is a different spatial dimension from the terminal orifices. This dimensional expansion of the venting system allows sufficient pressure relief capacity without compromising terminal structural integrity.
3Stability of the object's composition
If the support structure is made rigid to prevent collapse, then the venting mechanism remains stable, but the yieldable element cannot deform to open the vent under pressure
Solution Approach 1:
The support structure is segmented into a rigid support element and a separate yieldable element. The rigid support maintains structural stability and prevents collapse, while the yieldable element can deform under pressure to activate venting. This segmentation resolves the contradiction between support stability and venting activation.
Solution Approach 2:
The support structure incorporates both rigid and dynamic (yieldable) components. The rigid support provides structural stability, while the yieldable element introduces dynamic response capability that allows automatic venting activation under pressure without compromising overall structural stability.
4Reliability
If extensive pinpoint heating tests are conducted to identify weak points, then the vulnerability to rupture is identified, but the testing process is time-consuming and complex
Solution Approach 1:
The design incorporates a windowing feature that proactively addresses the identified vulnerability to washer collapse by providing an alternative venting pathway before failure can occur. This preliminary design action eliminates the need for extensive pinpoint heating tests to identify and mitigate the same vulnerability, reducing testing time while maintaining rupture resistance.
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
This solution effectively prevents cell rupture by ensuring unobstructed gas release during pressure buildup, reducing the risk of safety incidents and providing a greater safety margin compared to conventional designs.
Implementation Method 1
a yieldable element which yields under pressure
Implementation Method 2
the venting arrangement acts to vent gas responsive to pressure buildup within the battery cell
Data Source
AI summary
The provision of improved venting in battery cells by way of better preventing pressure buildup in the cells. Via different variants of the present invention, the following advantages are achieved:Gas can escape from the cell without clogging the vent;gas buildup is avoided while the venting valve can operate in a consistently reliable manner;the solutions presented are sufficiently versatile as to be applicable to a variety of cells on the market; andthe risk of explosion is virtually eliminated.