Secondary Battery Current Collector Welding Block for Stable Tab Joining
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Solution Overview
Problem
Existing secondary batteries face issues with poor welding quality and stability due to the use of composite current collecting plates, which can lead to gaps, damage to the electrode assembly, and increased contact resistance, making assembly difficult and unsafe.
Innovation Solution
A secondary battery design featuring a welding block with an annular first step structure that precisely positions with a connector piece, ensuring stable electrical connections and reducing the risk of weld mark detachment, using laser penetration welding to connect the welding block to the cover plate or shell body without penetrating the current collecting plate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a current collecting component is disposed near the opening of the shell body to achieve electrical connection, then electrical connectivity is improved, but positioning precision between the welding block and connector piece deteriorates
Solution Approach 1:
The current collecting component is divided into two separate parts: a connector piece that connects to the electrode assembly tab, and a welding block that connects to the shell body. This segmentation allows each part to be independently positioned and welded, improving both electrical connection reliability and manufacturing precision through separate optimization of each component's positioning.
2Strength
If laser penetration welding is used to connect the welding block to the cover plate, then welding strength is improved, but risk of damaging the electrode assembly increases
Solution Approach 1:
The welding block serves as an intermediary component between the current collecting component and the shell body. It provides a dedicated welding interface that is positioned away from the electrode assembly, allowing strong laser penetration welding to be performed on the welding block without the risk of damaging the electrode assembly. The welding block acts as a buffer that absorbs the welding energy and protects the sensitive electrode assembly from direct exposure to the laser and welding slag.
3Stability of the object's composition
If the welding block thickness is greater than the cover plate thickness, then welding stability is improved, but device complexity increases
Solution Approach 1:
The welding block is designed with non-uniform thickness distribution, featuring a first step structure with different thickness levels in different regions. The portion of the welding block that contacts the connector piece has a specific thickness optimized for welding stability, while other portions may have different thicknesses to reduce overall complexity and material usage. This local quality variation allows the welding interface to have enhanced stability without requiring the entire welding block to be uniformly thick, thus balancing welding stability with structural simplicity.
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 achieves precise positioning and stable electrical connections, reducing contact resistance and improving safety by preventing weld slag from damaging the electrode assembly, facilitating mass production, and enhancing the battery's reliability and energy density.
Implementation Method 1
using laser penetration welding to connect the welding block to the cover plate or shell body without penetrating the current collecting plate
Data Source
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AI summary
The disclosure provides a secondary battery (100), a battery pack (1002), and an electronic device (1000). The secondary battery (100), including a shell including a shell body (200) with an opening (113) formed at one end thereof and a cover plate (140) covering the opening (113) and connected to the shell body (200); an electrode assembly (120) accommodated in the shell body (200) and including a tab facing the cover plate (140); a current collecting component (130) including a connector piece (10) welded to the tab, and a welding block (20) surrounding the connector piece (10), the welding block (20) is provided with a first step structure (21), an edge portion (12) of the connector piece (10) is matched and connected with the first step structure (21), and the welding block (20) is welded to the shell.