Battery Cell End Cap Welding With an Intermediary Current Collector
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Solution Overview
Problem
Existing battery cells face safety issues due to potential microcracks and sealing failures at the interface between the end cap and the tab, leading to safety hazards and reduced airtightness.
Innovation Solution
A battery cell design that includes a current collecting member welded separately to both the end cap and the tab, with specific protrusions and recesses to avoid overlap and ensure reliable welding, thereby reducing microcracks and improving sealing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the end cap is directly welded to the tab, then the electrical connection is simple, but microcracks occur at the welding interface leading to sealing failures
Solution Approach 1:
A current collecting member is introduced as an intermediary component between the end cap and the tab. This current collecting member serves as a mediator that receives welding from the end cap and provides welding to the tab, thereby preventing direct welding between the end cap and tab that causes microcracks. The current collecting member absorbs the welding stress and prevents crack propagation to the end cap, ensuring sealing performance while maintaining electrical connection.
2Reliability
If the welding area is increased to improve electrical connection, then current capacity improves, but the risk of microcracks and sealing failures increases
Solution Approach 1:
The welding connection is segmented into two separate welding interfaces: one between the end cap and the current collecting member, and another between the current collecting member and the tab. This segmentation distributes the welding stress across two separate locations rather than concentrating it at a single interface, reducing the risk of microcracks. The current collecting member acts as a buffer that can accommodate welding variations without compromising the end cap sealing.
3Ease of manufacture
If the end cap structure is simplified, then manufacturing is easier, but welding precision and reliability are compromised
Solution Approach 1:
The current collecting member serves as an intermediary that decouples the manufacturing requirements of the end cap from the welding precision requirements. The end cap can be manufactured with standard precision using conventional processes, while the current collecting member provides the interface for precise welding to both the end cap and the tab, thereby separating and optimizing each manufacturing requirement independently.
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 design enhances safety by preventing microcracks, maintaining airtightness, and optimizing current density uniformity, reducing internal resistance, and increasing flow capacity while ensuring reliable electrical connections.
Implementation Method 1
the current collecting member is configured to be welded to the end cap and the first tab separately to implement electrical connection between the end cap and the first tab
Data Source
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AI summary
Some embodiments of this application provide a battery cell, a method and system for manufacturing same, a battery, and an electrical device. The battery cell according to an embodiment of this application includes: a housing, on which an opening is made; an electrode assembly, accommodated in the housing, where the electrode assembly includes a first tab at an end oriented toward the opening; an end cap, configured to fit and cover the opening to seal the electrode assembly in the housing; a current collecting member, disposed between the end cap and the first tab, where the current collecting member is configured to be welded to the end cap and the first tab separately to implement electrical connection between the end cap and the first tab. This application reduces the risk that microcracks occur on the end cap during welding of the end cap, and improves airtightness and safety.