Alternating Electrode Mixture and Irreversible Parts for Battery Efficiency
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Solution Overview
Problem
Lithium secondary batteries face inefficiencies due to differences in irreversible efficiency between positive and negative electrodes, leading to wasted active material and increased electrode resistance, particularly when high-capacity lithium-containing manganese oxides are used as positive electrodes and carbon-based materials as negative electrodes, causing difficulties in electrolyte impregnation and polarization.
Innovation Solution
An electrode structure is developed where electrode mixture parts with active materials and irreversible parts with additives are alternately arranged on a current collector, allowing for adjustable irreversible efficiency and improved electrolyte impregnation, reducing electrode resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an irreversible additive is added to the positive electrode to adjust efficiency, then the efficiency of the positive electrode is improved, but lithium escapes during initial formation and the irreversible additive becomes inactive, reducing energy density
Solution Approach 1:
The electrode is divided into electrode mixture parts and irreversible parts that are alternately arranged. The irreversible parts containing irreversible additives are separated from the electrode mixture parts, allowing the irreversible additives to remain active during initial formation while maintaining efficiency matching between electrodes.
Solution Approach 2:
Different regions of the electrode have different functions: electrode mixture parts provide active materials for energy storage, while irreversible parts provide irreversible additives for efficiency adjustment. This local differentiation allows each part to perform its specific function optimally without interfering with the other.
2Quantity of substance
If high loading of the electrode is used to increase battery capacity, then the capacity is improved, but the thickness of the electrode is increased making it difficult to be completely impregnated with electrolytic solution
Solution Approach 1:
The electrode is segmented into alternating electrode mixture parts and irreversible parts. This segmentation creates a structure with effective thickness control, allowing high loading of active materials while maintaining sufficient electrolyte penetration through the alternately arranged thinner sections.
3Quantity of substance
If high loading of the electrode is used to increase battery capacity, then the capacity is improved, but the concentration of the electrolytic solution is polarized increasing electrode resistance
Solution Approach 1:
The alternately arranged structure of electrode mixture parts and irreversible parts prevents severe electrolyte concentration polarization by creating multiple access points for electrolyte distribution, thereby reducing electrode resistance even at high loading.
4Quantity of substance
If the thickness of the electrode is increased to improve capacity, then the capacity is improved, but it becomes difficult for the electrode to be completely impregnated with electrolytic solution
Solution Approach 1:
The electrode structure is segmented into alternating parts with different thicknesses and functions. This segmentation maintains manufacturability by ensuring that no single section becomes excessively thick, thereby facilitating complete electrolyte impregnation while still achieving high overall capacity.
Solution Approach 2:
Different local regions of the electrode have optimized thicknesses: electrode mixture parts provide capacity while irreversible parts provide access channels for electrolyte penetration. This local quality optimization balances capacity requirements with manufacturing feasibility.
Data Source
AI summary
Disclosed herein are an electrode configured such that electrode mixture parts, each of which includes an electrode active material, and irreversible parts, each of which includes an irreversible additive, are alternately coated on one surface or both surfaces of a current collector to form an electrode pattern and a secondary battery including the same.