Secondary Battery Electrode Lead for All-Direction Bending
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Solution Overview
Problem
Conventional secondary batteries face issues with breakage of bonding portions due to external impacts and expansion/contraction during charging and discharging, particularly with belt-shaped tabs that are prone to stress concentration when subjected to external forces.
Innovation Solution
A secondary battery design featuring an electrode lead that is bendable in all directions, reducing stress concentration on bonding portions by allowing flexible bending, and a manufacturing method that bonds and bends this lead to connect the electrode assembly with the terminal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a belt-shaped tab is used to connect the electrode assembly with the terminal, then the manufacturing process is simplified, but stress concentrates on the bonding portion when external impact is applied, leading to breakage
Solution Approach 1:
The patent changes the geometric parameters of the tab from a belt-shaped cross-section to a circular cross-section. This parameter change allows the tab to be bendable in all directions rather than being restricted to bending in only one direction, thereby distributing stress uniformly across the bonding portion and preventing breakage under external impact while maintaining ease of manufacture
Solution Approach 2:
The patent makes the tab dynamically flexible by enabling bending in all directions through its circular cross-section design. This dynamic flexibility allows the tab to adapt to stress from any direction during battery expansion and contraction, preventing stress concentration and bonding portion breakage while simplifying the manufacturing process
2Device complexity
If the battery element moves in the width direction of the belt-shaped tab during external impact, then the structural simplicity is maintained, but the welded portion of the belt-shaped tab is damaged
Solution Approach 1:
The patent changes the cross-sectional shape parameter from rectangular (belt-shaped) to circular, which fundamentally alters the mechanical properties. The circular cross-section provides equal moment of inertia in all directions, enabling the tab to withstand impact forces from any direction without damaging the welded portion, while maintaining simple device structure
Solution Approach 2:
The patent employs a composite structure where the circular cross-section tab is formed from materials with appropriate mechanical properties that combine flexibility and strength. This composite approach allows the tab to absorb impact energy through controlled bending in all directions while maintaining structural integrity of the welded portions
Data Source
AI summary
A secondary battery that includes an electrode assembly having a positive electrode, a negative electrode, and a separator between the positive electrode and the negative electrode; an exterior body that houses the electrode assembly; a terminal electrically connected to the positive electrode or the negative electrode; and an electrode lead electrically connected to the terminal and the positive electrode or the negative electrode, the electrode lead being bendable in all directions.