Battery Housing Venting Structure for Thermal Runaway Gas Discharge
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Solution Overview
Problem
Existing battery systems face challenges in reliably guiding away hot gases during thermal runaway to prevent thermal propagation and penetration into the passenger compartment, which is critical for lithium-ion batteries in the electromobility sector.
Innovation Solution
A battery design featuring a perforated sheet with degassing openings for each cell, sealed by a foam that melts upon thermal runaway to allow gas escape, combined with a sealing layer that breaks to ensure gas discharge and a trough for impact absorption, ensuring reliable gas removal and structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the battery housing is sealed to prevent gas penetration into the passenger compartment, then safety is improved, but thermal runaway gases cannot escape causing pressure buildup and potential structural damage
Solution Approach 1:
The battery housing incorporates a perforated sheet with numerous small openings distributed across its surface. This porous structure allows thermal runaway gases to escape through the multiple small channels rather than creating pressure buildup, while still maintaining overall containment to prevent gas penetration into the passenger compartment.
Solution Approach 2:
The perforated sheet acts as an intermediary element between the sealed battery housing and the external environment. It mediates the conflicting requirements by providing a controlled interface that allows gas passage while maintaining the sealed structure, thus resolving the contradiction between containment and venting.
2Object-generated harmful factors
If degassing openings are provided for each battery cell, then thermal runaway gas escape is improved, but structural integrity and rigidity of the battery housing deteriorate
Solution Approach 1:
Instead of providing large individual openings for each battery cell, the patent uses a perforated sheet with numerous small openings. This approach maintains structural integrity because the small holes create minimal stress concentrations and preserve the overall strength of the housing material, while still providing adequate escape paths for gases from multiple cells simultaneously.
Solution Approach 2:
The degassing function is segmented across the entire housing surface through the distributed perforations, rather than concentrating large openings at specific locations. This segmentation allows gas escape from multiple battery cells through distributed small openings, maintaining structural integrity while providing comprehensive venting capability.
3Strength
If a solid floor structure is used in the battery housing, then structural rigidity is improved, but thermal runaway gases cannot be effectively discharged
Solution Approach 1:
The solid floor structure is replaced with a perforated sheet that maintains rigidity through its distributed opening pattern. The numerous small openings provide effective gas discharge pathways while the overall sheet structure retains sufficient structural rigidity to support the battery assembly and maintain housing integrity.
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 gas penetration into the passenger compartment and thermal propagation, maintaining structural integrity and safety by efficiently discharging gases, while allowing for easy repair and reduced weight.
Implementation Method 1
the sealing layer is designed so as, in the event of a thermal runaway of the battery cell, to open up the degassing opening (28) assigned to this battery cell (12). This can be undertaken by the sealing layer (30) locally melting and therefore opening up a passage from the battery cell (12) to the degassing opening (28)
Implementation Method 2
In order, during normal operation of the battery (10), to ensure tightness of the housing interior (16), in particular the tightness in relation to water so as to avoid an ingress of water into the housing interior (16), the sealing layer (30) is provided. This sealing layer (30) together with the perforated sheet (20) thus provides respective predetermined breaking points by means of which the degassing openings (28) are closed during normal operation and via which the associated degassing opening (28) is opened by means of the hot gases in the event of the thermal runaway of at least one of the battery cells (12)
Data Source
AI summary
A battery for a motor vehicle has a plurality of battery cells and a battery housing that encloses a housing interior in which the battery cells are received. The battery housing has a perforated sheet on which the battery cells are placed. The perforated sheet has, for each battery cell, an allocated degassing opening on which the allocated battery cell is placed and via which gas exiting the allocated battery cell can be guided out of the housing interior.