Cylindrical Battery Bottom Surface Gas Venting Design
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Solution Overview
Problem
In connected storage cells, the risk of the gas discharging section opening due to vibration or external pressure through the connecting member poses a challenge, particularly during weld strength testing, as it can lead to premature gas discharge when internal pressure reaches a predetermined level.
Innovation Solution
The design features a cylindrical cell case with multiple gas discharging sections on the bottom surface, separated and arranged to open when internal pressure increases, and a connecting member welded to a non-opening section between these sections, ensuring the bottom surface remains closed under external forces and allowing controlled gas discharge when pressure is reached.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the connecting member is welded to the gas discharging section, then the structural integrity is improved, but the gas discharging section may open due to vibration or external pressure
Solution Approach 1:
The bottom surface portion is divided into multiple functional zones: gas discharging sections (with lower strength for pressure relief) and non-opening sections (with higher strength for mechanical connection). This segmentation allows the connecting member to be welded to the non-opening section, preventing unintended opening while maintaining structural integrity.
Solution Approach 2:
Different regions of the bottom surface portion are given different mechanical properties. The gas discharging sections are designed with lower strength to open at predetermined pressure, while the non-opening section has higher strength to resist opening under external pressure and vibration, ensuring both functions coexist without interference.
2Productivity
If the bottom surface portion is largely opened for gas discharge, then the gas discharge efficiency is improved, but the structural integrity during normal operation deteriorates
Solution Approach 1:
The bottom surface is segmented into multiple gas discharging sections distributed across the area. When pressure builds up, these sections open to provide large total discharge area for efficient gas release, while the remaining non-opening sections maintain structural integrity during normal operation.
Solution Approach 2:
Specific localized regions (gas discharging sections) are designed with lower strength to facilitate opening under pressure, while other regions (non-opening sections) maintain higher strength for structural support. This local differentiation allows the bottom surface to provide both structural integrity and efficient gas discharge capability.
Data Source
AI summary
A battery pack includes a plurality of unit cells, each including a cylindrical battery case, and a connecting member (12) that connects the unit cells to each other. The battery case of each unit cell includes a bottom surface portion (30b) including a plurality of gas discharging sections (32) that open when an internal pressure of the unit cell reaches a predetermined pressure. The gas discharging sections (32) are separated from each other. The connecting member (12) is joined to a non-opening section (34) of the bottom surface portion (30b), the non-opening section (34) being disposed between the gas discharging sections (32).