Electrode Assembly Barrier Layer for Bend-Region Lithium Plating
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Solution Overview
Problem
Lithium plating in batteries leads to dendrite formation, which can cause internal short circuits and safety hazards, affecting both electrical and safety performance.
Innovation Solution
Incorporating a barrier layer between the positive current collecting layer and the positive active material layer in the bend regions of the electrode assembly to prevent electron transport, thereby reducing lithium plating and improving safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a barrier layer is added between the positive current collecting layer and positive active material layer, then lithium plating is reduced and safety is improved, but device complexity increases
Solution Approach 1:
The positive electrode plate is segmented into multiple bend portions within the bend region, with barrier layers selectively applied to specific segments. This allows the barrier function to be localized to where it is most needed (at bend portions prone to lithium plating) rather than applying it uniformly across the entire electrode, thus reducing overall complexity while maintaining safety benefits.
Solution Approach 2:
The barrier layer acts as an intermediary component between the positive current collecting layer and positive active material layer. It mediates electron transport by blocking it at critical bend portions, preventing delithiation reactions that lead to lithium plating. This intermediary structure addresses the safety issue without requiring fundamental redesign of the entire electrode assembly.
2Reliability
If electron transport is prevented at bend portions, then delithiation reactions are weakened and lithium plating is reduced, but energy density may be affected
Solution Approach 1:
The barrier layer is applied locally only at bend portions where lithium plating is most likely to occur, rather than uniformly across the entire positive electrode plate. This localized application allows electron transport to be blocked where needed for safety while preserving normal electrochemical reactions in non-bend regions, thus maintaining energy density while preventing lithium plating.
Solution Approach 2:
Instead of preventing electron transport across the entire positive electrode plate (which would excessively reduce energy density), the barrier layer is applied partially only at critical bend portions. This partial action is sufficient to prevent lithium plating at the most vulnerable locations while minimizing impact on overall battery performance and energy density.
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 barrier layer effectively reduces lithium plating, enhancing battery safety and maintaining high energy density by minimizing electron transport and delithiation reactions.
Implementation Method 1
A barrier layer is disposed between the positive current collecting layer and the positive active material layer. The barrier layer is configured to prevent electron transport between the positive current collecting layer and the positive active material layer.
Data Source
AI summary
An electrode assembly, a battery cell, a battery, and a method and device for manufacturing an electrode assembly are provided. In some embodiments, the electrode assembly includes a positive electrode plate and a negative electrode plate. The positive electrode plate and the negative electrode plate are wound or folded to form a bend region. The positive electrode plate includes a plurality of bend portions located in the bend region. Each bend portion includes a positive current collecting layer and a positive active material layer. The positive current collecting layer is coated with the positive active material layer on at least one surface in a thickness direction of the positive electrode plate. A barrier layer is disposed between the positive current collecting layer and the positive active material layer.