Segmented Electrode Tab Assembly to Prevent Plate Cracking
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Solution Overview
Problem
Cylindrical secondary batteries face issues with electrode plate bending and cracking due to the edge of the electrode tab during winding and repeated charging and discharging, leading to reduced lifespan.
Innovation Solution
The electrode assembly includes a pair of electrode plates with a separator and an electrode tab featuring conductive wires arranged side by side, with overlapping and protruding parts bonded to uncoated regions of the electrode plates, and a reinforcing thin plate, using ultrasonic welding to secure the conductive wires to the electrode plates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single electrode tab is used to connect electrode plates, then the electrode assembly structure is simple, but the electrode plate may be bent and cracked due to concentrated stress at the tab edge
Solution Approach 1:
The single electrode tab is segmented into multiple conductive wires arranged side by side. This segmentation distributes the mechanical stress that was previously concentrated at a single tab edge across multiple wire edges, preventing bending and cracking of the electrode plate while maintaining structural simplicity
Solution Approach 2:
The electrode tab uses multiple thin conductive wires instead of a single thick tab, creating different local properties: each wire has a smaller contact area with the electrode plate, distributing stress locally and preventing concentrated stress damage while maintaining overall electrical conductivity
2Volume of moving object
If electrode plates are wound into jelly roll shape, then the battery can be accommodated in cylindrical case, but the electrode plate may be bent and pressed by electrode tab edge during winding
Solution Approach 1:
The electrode tab is divided into multiple conductive wires, which reduces the bending moment and pressure exerted on the electrode plate during the winding process. The segmented structure is more flexible and less likely to cause damage when wrapped around the cylindrical form
3Duration of action of moving object
If repeated charging and discharging occurs, then the battery provides continuous operation, but the electrode plate may swell and be cracked by electrode tab edge
Solution Approach 1:
Multiple conductive wires distribute the mechanical stress from electrode plate swelling across multiple contact points rather than a single edge, preventing crack formation and maintaining structural integrity during repeated charging and discharging cycles
Solution Approach 2:
The electrode tab structure changes from a single solid piece to multiple thin wires, altering the mechanical parameters (stress distribution, flexibility) to accommodate the dynamic swelling and shrinking of the electrode plate during charge-discharge cycles without causing damage
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
This design prevents damage to the electrode plates, enhancing the durability and lifespan of the secondary battery by minimizing stress and cracking during charging and discharging processes.
Implementation Method 1
using ultrasonic welding to secure the conductive wires to the electrode plates
Data Source
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AI summary
An electrode assembly, a method for fabricating the electrode assembly, and a secondary battery including the electrode assembly are disclosed. An electrode assembly includes a pair of electrode plates, a separator between the pair of electrode plates, and an electrode tab including a plurality of conductive wires arranged side by side in a width direction, and each of the plurality of conductive wires includes an overlapping part that overlaps an electrode plate of the pair of electrode plates to be bonded to the electrode plate, and a protruding part connected to the overlapping part and protruding to an outside at a boundary of the electrode plates.