Battery Cell End Cap Structure for Tab Clearance and Pressure Relief
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Solution Overview
Problem
Existing battery cells face safety issues due to premature rupture of pressure relief mechanisms caused by electrode assembly tabs impacting fragile portions during vibration, leading to potential failure and safety hazards.
Innovation Solution
The end cap is designed with a protruding portion that supports the tab, creating an avoidance clearance to prevent the tab from crushing the fragile portion, and incorporates a current collecting member to ensure uniform current distribution and reduce internal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the end cap directly contacts the tab during assembly, then the assembly process is simple, but the fragile portion is crushed by the tab causing premature rupture and safety failure
Solution Approach 1:
The end cap is segmented into multiple functional regions: a cap body, a first protruding portion that contacts and supports the tab, and a fragile portion positioned away from the tab. This segmentation allows the tab-contacting function and the pressure-relief function to be separated spatially, preventing the tab from crushing the fragile portion while maintaining structural integrity.
Solution Approach 2:
Different regions of the end cap are designed with different local properties: the first protruding portion has enhanced mechanical strength to support the tab, while the fragile portion is designed with reduced strength to rupture at predetermined pressure. This local differentiation allows each region to perform its specific function optimally without interfering with others.
2Reliability
If the fragile portion is positioned close to the tab for compact design, then the device size is reduced, but the tab crushes the fragile portion during vibration causing premature failure
Solution Approach 1:
The fragile portion is repositioned from a planar arrangement near the tab to a three-dimensional arrangement on the outer surface of the cap body, away from the tab. This spatial reconfiguration in the third dimension maintains compact overall size while ensuring sufficient separation between the tab and fragile portion to prevent crushing during vibration.
3Reliability
If the end cap structure is simplified without protruding portions, then manufacturing is easier, but current distribution becomes uneven increasing internal resistance
Solution Approach 1:
The first protruding portion serves multiple functions simultaneously: it provides mechanical support to the tab to prevent crushing of the fragile portion, acts as a current collection point to improve current distribution uniformity, and reduces internal resistance. This multi-functionality achieves electrical and mechanical benefits without significantly complicating the manufacturing process.
Data Source
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AI summary
Embodiments of this application provide a battery cell (7), a method and system for manufacturing same, a battery, and an electrical device. The battery cell (7) includes: a housing (20), on which an opening (21) is made; an electrode assembly (10), accommodated in the housing (20), where a first tab (12) is disposed on the electrode assembly (10) at an end oriented toward the opening (21); and an end cap (30), configured to fit and cover the opening (21). The end cap (30) includes a cap body (31) and a first protruding portion (32) connected to the cap body (31). A fragile portion (311) is disposed on the cap body (31). The end cap (30) is configured to rupture along the fragile portion (311) when an internal pressure of the battery cell (7) reaches a threshold, so as to release the internal pressure. The first protruding portion (32) protrudes from the cap body (31) toward the electrode assembly (10), and is configured to support the first tab (12) so that an avoidance clearance (G) configured to avoid the fragile portion (311) is formed between the first tab (12) and the cap body (31). This application reduces the risk that the first tab (12) crushes the fragile portion (311), and improves the sealing performance and safety performance of the battery cell (7).