Traction Battery Pack Venting Assembly for Thermal Cascade Containment
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Solution Overview
Problem
Traction battery packs in electrified vehicles face challenges in effectively venting gas and debris due to increased pressure and thermal energy, which can lead to thermal events and cascading damage to non-venting cells.
Innovation Solution
A venting assembly is introduced, comprising a cross-member assembly with valve assemblies that open to provide a controlled vent path from battery cell compartments to a passageway, using various configurations such as flaps, perforated areas, and adhesive tapes to redirect flow away from non-venting cells, ensuring safe release of gas and debris.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If battery cells are arranged in compartments without dividers, then device complexity is reduced, but thermal events can spread to non-venting cells causing cascading damage
Solution Approach 1:
The battery pack is divided into multiple compartments using dividers, with each compartment containing one or more battery cells. This segmentation isolates thermal events to specific compartments, preventing heat and debris from affecting adjacent cells, thus improving reliability while maintaining manageable device complexity.
2Stress or pressure
If gas and debris are vented directly without control, then pressure relief is achieved, but thermal energy spreads to non-venting cells causing cascading damage
Solution Approach 1:
A venting assembly with a valve is introduced as an intermediary component between the battery cells and the external environment. The valve controls the venting process, allowing pressure relief while directing gas and debris through a designated path that prevents thermal energy from spreading to non-venting cells, thus resolving the contradiction between pressure relief and thermal containment.
3Reliability
If valve assemblies are added to control venting, then thermal cascade prevention is improved, but device complexity increases
Solution Approach 1:
The venting assembly incorporates a valve that automatically responds to pressure changes within the battery compartments. When pressure exceeds a threshold, the valve opens to relieve pressure; when pressure normalizes, the valve closes. This self-service mechanism provides thermal cascade prevention without requiring external control systems, thereby improving reliability 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 solution effectively directs vented gas and debris away from non-venting cells, preventing thermal cascades and ensuring safe external discharge, thereby enhancing the safety and reliability of traction battery packs.
Implementation Method 1
From time to time, pressure and thermal energy within one or more of the battery cells can increase. Gas and debris can then be released from those battery cells.
Implementation Method 2
a valve assembly that opens to provide a vent path from the at least one cell stack to a passageway of the cross-member assembly
Implementation Method 3
a baffle of the cross-member assembly that redirects flow through the opening to move toward an axial end of the cross-member assembly
Implementation Method 4
a plurality of flaps that open without inverting to permit flow through the valve assembly in a first direction, wherein inverting the plurality of flaps is necessary to permit flow through the valve assembly is an opposite, second direction
Data Source
AI summary
A traction battery pack venting assembly includes an enclosure, at least one cell stack within the enclosure, a cross-member assembly within the enclosure, and a valve assembly that opens to provide a vent path from the at least one cell stack to a passageway of the cross-member assembly. A method of establishing a vent path within a traction battery pack includes, within a battery pack enclosure, using a valve assembly to block an opening to a passageway provided by a cross-member assembly; and in response to at least one battery cell within the battery pack enclosure venting, opening the valve assembly to permit flow through the opening to the passageway.