Layered Lithium Metal Negative Electrode to Prevent Detachment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional lithium secondary batteries face issues with lithium metal detachment from the negative electrode in areas not in contact with the positive electrode, leading to reduced energy density and safety concerns.
Innovation Solution
The negative electrode for lithium secondary batteries is designed with a multi-layer structure, including a first and third layer of lithium metal sheets and a second layer with a lithium metal sheet surrounded by a negative electrode collector. This structure enhances adhesion and prevents lithium metal detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the negative electrode size is made larger than the positive electrode to increase capacity, then the energy density is improved, but the lithium metal detachment risk increases in the non-contact area
Solution Approach 1:
The negative electrode is divided into multiple layers (first negative electrode layer, second negative electrode layer, third negative electrode layer) with the separator positioned between them. This segmentation allows the lithium metal to be distributed across multiple layers rather than concentrated in one large layer, reducing detachment risk while maintaining total capacity.
Solution Approach 2:
The invention transitions from a single-plane negative electrode to a multi-layer stacked structure extending in the vertical dimension. The first, second, and third negative electrode layers are arranged in sequence with the separator between them, creating a three-dimensional configuration that increases adhesion contact areas while maintaining overall capacity.
2Quantity of substance
If the negative electrode is made larger than the positive electrode, then the theoretical capacity is improved, but the structural stability deteriorates due to repeated charging/discharging
Solution Approach 1:
The negative electrode is segmented into multiple thinner layers (first, second, and third negative electrode layers) rather than one thick layer. This segmentation reduces the porosity increase and rigidity loss that occur during repeated charging/discharging, maintaining structural stability while preserving total lithium capacity.
Solution Approach 2:
The multi-layer stacked configuration distributes the mechanical stress and structural degradation across multiple layers rather than concentrating it in a single large electrode. This dimensional distribution enhances overall structural stability during repeated cycling.
3Quantity of substance
If lithium metal detachment occurs in the non-contact area, then the energy density is reduced, but also safety hazards increase due to potential short circuits
Solution Approach 1:
By segmenting the negative electrode into multiple layers separated by the separator, the invention ensures that lithium metal remains confined within the structured layers. This prevents detachment and free movement of lithium pieces that could cause short circuits, while maintaining effective lithium utilization.
Solution Approach 2:
The separator acts as an intermediary barrier between the first, second, and third negative electrode layers. This intermediary structure prevents direct contact between lithium metal pieces from different layers, eliminating the short circuit hazard while allowing ionic transport for normal battery operation.
Data Source
AI summary
The present disclosure relates to a negative electrode for a lithium secondary battery and a lithium secondary battery including the same. The negative electrode for the lithium secondary battery includes: a first layer including a first lithium metal sheet; a second layer formed on a top surface of the first layer and including a second lithium metal sheet and a negative electrode collector surrounding an outer peripheral surface of the second lithium metal sheet; and a third layer formed on a top surface of the second layer and including a third lithium metal sheet.