Pouch Cell Module Venting Structure for Thermal Runaway Containment
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Solution Overview
Problem
Existing battery modules face issues with directional venting of high-temperature gases during thermal events, leading to potential damage and combustion due to unexpected discharge paths, and lack sufficient support and rigidity for pouch-type battery cells.
Innovation Solution
A battery module design featuring a cell cover that surrounds pouch-type battery cells and bus-bar frame assemblies, with a symmetrical structure and side openings, coupled with a module case having a gas venting hole at the bottom, ensuring directional venting and enhanced support and rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cell unit group is configured by stacking multiple cell units with pouch-type battery cells, then thermal runaway propagation can be blocked and directional venting can be achieved, but assembly tolerances create gaps that allow venting gases to escape in unexpected directions
Solution Approach 1:
A sealing member is introduced as an intermediary component between the cell unit group and the bus-bar frame assembly. This sealing member fills the gap created by assembly tolerances, preventing venting gases from escaping through unintended paths while maintaining the directional venting function through the designated venting hole.
Solution Approach 2:
The sealing member is pre-installed on the bus-bar frame assembly before final assembly with the cell unit group. This beforehand cushioning approach ensures that the gap is sealed in advance, preventing potential gas leakage paths before thermal events occur, thereby improving reliability without requiring tighter manufacturing tolerances.
2Quantity of substance
If pouch-type battery cells are stacked to increase capacity, then energy density improves, but the cells lack sufficient support and rigidity
Solution Approach 1:
The cell cover acts as a flexible shell structure that surrounds and supports the pouch-type battery cells. This thin film-like cover provides necessary mechanical support and rigidity to the soft pouch cells, enabling them to be stacked vertically to increase capacity while maintaining structural integrity.
Solution Approach 2:
The battery module is segmented into multiple cell units, each containing pouch-type battery cells stacked vertically within a cell cover. This segmentation allows the cells to be arranged in a compact stacked configuration, increasing overall capacity while each segment maintains its own structural support through the cell cover.
3Temperature
If venting gases are allowed to escape during thermal events, then pressure relief is achieved, but thermal damage can spread to surrounding areas
Solution Approach 1:
The harmful hot venting gases are extracted and directed through a dedicated venting hole in the module case, separating the thermal event containment within the cell unit from the surrounding environment. This extraction approach allows pressure relief while preventing thermal damage propagation to adjacent battery modules or components.
Solution Approach 2:
The harmful hot gases generated during thermal runaway are converted into a controlled venting flow that exits through a designated path. By directing the harmful thermal energy through a controlled route, the system transforms an uncontrolled dangerous event into a managed pressure relief process that protects surrounding areas.
Data Source
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AI summary
A battery module according to the present disclosure includes: a cell unit stack comprised of a plurality of cell units stacked in one direction; a bus-bar frame assembly disposed inside the cell unit stack and configured to electrically connect pouch-type battery cells; and a module case configured to store the cell unit stack and the bus-bar frame assembly, wherein the cell unit comprises: at least one pouch-type battery cell; and a cell cover configured to surround the pouch-type battery cell and the bus-bar frame assembly and having an open bottom.