Wound Electrode Assembly Tape Layout to Prevent Core Collapse
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Solution Overview
Problem
Jelly-roll type electrode assemblies in secondary batteries face issues with separator damage and core collapse, leading to reduced lifespan and potential ignition due to disconnection at the positive electrode core end.
Innovation Solution
A winding-type electrode assembly design featuring a positive electrode with a non-coating portion and tab, a negative electrode with a core-side non-coating portion and tab, and protective tapes attached over the negative electrode non-coating and active material portions to prevent short-circuiting and core collapse during winding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a jelly-roll type electrode assembly is used for easy manufacturing and high energy density, then manufacturing efficiency and energy density are improved, but separator damage and core collapse occur leading to reduced reliability
Solution Approach 1:
The invention applies preliminary action by pre-attaching protective tapes to the positive electrode core portion before the winding process. This preventive measure ensures that the separator is protected from damage at the core region where it is most vulnerable during winding, thereby maintaining separator integrity while preserving the efficiency benefits of the jelly-roll structure
Solution Approach 2:
The protective tape serves as a cushioning element attached beforehand to the positive electrode core. This cushioning prevents direct contact and potential damage between the separator and the core structure during winding, absorbing mechanical stresses that would otherwise compromise separator integrity
2Quantity of substance
If a jelly-roll type electrode assembly is used for high energy density, then capacity per weight is improved, but core collapse occurs affecting lifespan characteristics
Solution Approach 1:
The protective tape is attached to the positive electrode core in advance of the winding process, creating a reinforced core structure that prevents collapse during assembly and throughout the battery's operational life, thereby preserving both energy density and lifespan
Solution Approach 2:
The protective tape functions as a thin film reinforcement on the positive electrode core, providing structural support that prevents core collapse while maintaining the compact jelly-roll configuration necessary for high energy density
3Volume of moving object
If the separator is disposed in the core part of the jelly-roll structure, then winding compactness is improved, but the separator becomes disconnected by the positive electrode core end causing ignition
Solution Approach 1:
The protective tape is positioned beforehand at the positive electrode core where separator disconnection is most likely to occur. This cushioning layer prevents the separator from being torn or disconnected by the core end, eliminating the ignition hazard while maintaining compact winding
Solution Approach 2:
The protective tape acts as an intermediary element between the positive electrode core and the separator. It mediates the interaction by providing a protective barrier that prevents direct harmful contact, thereby preventing separator disconnection while allowing the compact jelly-roll structure to be maintained
Data Source
AI summary
A winding type electrode assembly includes a positive electrode having a positive electrode collector that includes a positive electrode active material portion and a positive electrode non-coating portion; a positive electrode tab provided on the positive electrode non-coating portion; a negative electrode having a negative current collection that includes a negative electrode active material portion and a negative electrode non-coating portion; a negative electrode tab provided on the negative electrode non-coating portion; a protective tape and a separator configured to insulate the positive electrode from the negative electrode. The negative electrode non-coating portion includes a core-side negative electrode non-coating portion disposed at a core when the positive electrode, the negative electrode, and the separator are wound. The negative electrode tab is disposed on one surface of opposite surfaces of the core-side negative electrode non-coating portion. The protective tape is attached over the core-side negative electrode non-coating portion.