Battery Pack Venting Guide for Thermal Runaway Gas Isolation
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Solution Overview
Problem
Secondary battery modules are prone to thermal runaway and gas generation due to external impacts and harsh charging/discharging cycles, which can lead to ignition and the transfer of high-temperature gases or flames to adjacent modules.
Innovation Solution
A battery pack design incorporating a protective sheet and venting guide member with an internal space, where the gas discharged from the cell assembly passes through the protective sheet and exhaust portion, directing it into the venting guide member's internal space, and then externally through discharge holes, preventing gas transfer to adjacent modules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a venting hole is formed in the protective cover to discharge gas from the cell assembly, then gas discharge function is improved, but high-temperature gas may transfer to adjacent battery modules causing thermal runaway
Solution Approach 1:
The patent introduces a protective sheet as an intermediary component between the venting hole and the external environment. This protective sheet includes a vulnerable portion that selectively opens under gas pressure to create a discharge path, while the surrounding intact portions continue to block gas transfer to adjacent modules. The intermediary structure enables both gas discharge and thermal runaway prevention functions to coexist.
Solution Approach 2:
The protective sheet is segmented into a vulnerable portion and surrounding intact portions with different functions. The vulnerable portion opens to allow gas discharge when pressed by internal gas pressure, while the surrounding intact portions remain closed to prevent gas transfer to adjacent battery modules. This segmentation allows the single protective sheet to simultaneously achieve both gas discharge and thermal runaway prevention.
2Reliability
If the protective sheet is made fully sealed to prevent gas transfer, then thermal runaway prevention is improved, but gas discharge from the cell assembly is blocked
Solution Approach 1:
The protective sheet exhibits local quality differentiation where different portions have different permeability characteristics. The vulnerable portion is designed with lower strength to open under gas pressure for discharge, while the surrounding portions maintain high strength and remain sealed to prevent gas transfer. This local quality variation allows the protective sheet to simultaneously achieve selective gas discharge and thermal runaway prevention.
3Object-generated harmful factors
If the vulnerable portion opens completely to discharge gas, then gas discharge is improved, but the protective sheet loses its barrier function
Solution Approach 1:
The protective sheet is segmented into a vulnerable portion that opens for gas discharge and surrounding intact portions that maintain the barrier function. The segmentation ensures that when the vulnerable portion opens under gas pressure, the surrounding intact portions remain closed and continue to prevent gas transfer to adjacent modules, thus preserving the overall barrier function while enabling controlled gas discharge.
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 reduces or prevents thermal runaway and gas transfer between battery modules, enhancing safety by managing and dissipating high-temperature gases and flames externally.
Implementation Method 1
a protective sheet disposed to face the venting hole... the gas discharged from the cell assembly moves to the internal space of the venting guide member, passing through the protective sheet and the exhaust portion
Implementation Method 2
a venting guide member having an internal space, and contacting the protective sheet, wherein the venting guide member includes an exhaust portion formed on one surface in contact with the protective sheet, and the gas discharged from the cell assembly moves to the internal space of the venting guide member
Data Source
AI summary
A battery pack is provided, the battery pack including: a plurality of battery modules including a cell assembly in which a plurality of battery cells are assembled and a protective cover on which the cell assembly is seated and in which a venting hole is formed; a pack case protecting the plurality of battery modules from the outside; a protective sheet disposed to face the venting hole, and configured to have a hole formed in at least a portion of the protective sheet by gas discharged from the cell assembly; and a venting guide member having an internal space, and contacting the protective sheet, wherein the venting guide member includes an exhaust portion formed on one surface in contact with the protective sheet, and the gas discharged from the cell assembly moves to the internal space of the venting guide member, passing through the protective sheet and the exhaust portion.