Bottom-Vented Secondary Battery Vent Gap for Thermal Runaway Degassing
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Solution Overview
Problem
In bottom-vented secondary batteries, the case can be destroyed during events like thermal runaway due to increased degassing paths, which compromises the battery's safety and performance.
Innovation Solution
A secondary battery design that includes a case with an electrode assembly, a first cap plate, a vent opposite the first cap plate, and a gap-maintaining part to ensure a consistent gap of at least 0.7 mm between the electrode assembly and the vent, enhancing degassing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the vent is installed at the bottom of the case in a bottom-vented secondary battery, then the degassing performance is improved, but the case may be destroyed during thermal runaway due to increased degassing path
Solution Approach 1:
The invention introduces a gap-maintaining part that segments the internal space of the case, creating a dedicated gap between the electrode assembly and the vent. This segmentation allows the degassing function to be optimized while the case structure remains intact, as the gap directs gas flow through a controlled path rather than compromising the case walls.
Solution Approach 2:
The gap-maintaining part acts as an intermediary element between the electrode assembly and the vent. It mediates the degassing process by maintaining a stable gap that guides gas flow to the vent, enabling effective degassing without requiring the case to be compromised or destroyed during thermal runaway events.
2Reliability
If the gap between the electrode assembly and the vent is increased to improve degassing, then the degassing path is enhanced, but the internal space utilization is reduced
Solution Approach 1:
The gap-maintaining part creates a localized gap structure only in the specific region between the electrode assembly and the vent, rather than increasing gaps throughout the entire battery. This local quality approach ensures adequate degassing performance while minimizing the overall impact on internal space utilization.
Solution Approach 2:
The invention addresses the space utilization issue by configuring the gap-maintaining part in a specific spatial arrangement (e.g., positioned at peripheral regions or utilizing vertical space), effectively using another dimension to accommodate the gap without significantly reducing the horizontal packing density of the electrode assembly.
3Reliability
If the gap-maintaining part is added to maintain a stable gap, then the degassing path stability is improved, but the device complexity increases
Solution Approach 1:
The gap-maintaining part is implemented as a thin structural element (such as a thin film or shell-like component) that maintains the gap stability without adding significant structural complexity. This thin-film approach provides the necessary gap maintenance function while minimizing the increase in device complexity.
Solution Approach 2:
The gap-maintaining part is integrated with existing battery components (such as being formed as part of the case structure or combined with the vent assembly), merging multiple functions into a single element. This integration reduces the overall device complexity compared to adding a completely separate component.
Data Source
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AI summary
Disclosed herein is a secondary battery including a vent through which gas may be discharged in the event of an internal event, and a method of manufacturing the same, and which provides a structure for ensuring a gas passage within the bottom-vented secondary battery to avoid destruction of a case if an event occurs or during thermal runaway due to an increase in degassing path in the secondary battery. To this end, there are provided a secondary battery, which includes a case, an electrode assembly in the case, a first cap plate coupled to the case, a vent opposite the first cap plate, and a gap-maintaining part for maintaining a gap between the electrode assembly and the vent, a method of manufacturing the same, and a vehicle including the secondary battery.