Lithium-Ion Battery Electrode Barrier and Interconnecting Layers
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Solution Overview
Problem
Existing electrodes using aqueous active material compositions for lithium ion batteries face issues with decreased battery capacity and discharge characteristics due to reactions between the active material and water, leading to increased initial internal resistance, particularly when using lithium transition metal oxides as positive electrode materials.
Innovation Solution
The introduction of a barrier layer with a non-water-soluble polymeric material and a conductive material on the power collector, combined with an interconnecting layer with a higher conductive material ratio than the barrier layer, to inhibit direct contact between water and the power collector, thereby reducing resistance and maintaining high water resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a barrier layer containing conductive material and binder is provided on the power collector to prevent water contact, then water resistance is improved, but electrical conductivity deteriorates due to the need for higher binder content
Solution Approach 1:
The electrode structure is divided into three distinct layers: a barrier layer for water resistance, an interconnecting layer for electrical conductivity, and an active material layer for battery function. This segmentation allows each layer to optimize its specific function without compromising the others, resolving the contradiction between water resistance and electrical conductivity.
Solution Approach 2:
The interconnecting layer acts as an intermediary between the barrier layer and the active material layer. It provides the necessary electrical conductivity pathway while the barrier layer maintains water resistance. This intermediary layer resolves the contradiction by mediating between the conflicting requirements of water protection and electrical conduction.
2Ease of manufacture
If aqueous active material composition is used to form the active material layer, then ease of manufacture is improved, but harmful factors increase due to reactions between active material and water
Solution Approach 1:
The barrier layer is provided in advance on the power collector before applying the aqueous active material composition. This preliminary protective action prevents water from contacting the power collector and forming harmful compounds, allowing the use of aqueous composition without generating harmful factors.
Solution Approach 2:
The barrier layer serves as an intermediary that allows the aqueous active material composition to be applied easily while preventing the harmful reaction between water and the power collector. This intermediary enables the use of aqueous composition (improving ease of manufacture) while preventing the formation of high-resistance compounds (eliminating harmful factors).
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 configuration enhances electrical conductivity between the active material layer and the power collector while ensuring high water resistance, resulting in a more stable and high-performance electrode for lithium ion batteries.
Implementation Method 1
a barrier layer which contains a non-water-soluble polymeric material and a conductive material
Implementation Method 2
an interconnecting layer which contains a polymeric material and a conductive material and has higher electrical conductivity than the barrier layer
Data Source
AI summary
An electrode 30 (such as a positive electrode for a lithium ion battery) is provided in which an active material layer (35), having an electrode active material as a main component thereof, is held by a metallic power collector (32). A barrier layer (33) containing a non-water-soluble polymeric material (334) and a conductive material (332) is provided on the surface of the power collector (32). An interconnecting layer (34), having higher electrical conductivity than the barrier layer (33) and containing a polymeric material (344) and a conductive material (342), is interposed between the barrier layer (33) and the active material layer (35).