Solid Lithium Ion Battery Electrode Conductive Matrix
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Solution Overview
Problem
Existing multilayer all solid state lithium ion secondary batteries face challenges with high electrode impedance due to low conductivity of active materials, leading to reduced discharge capacity and increased manufacturing complexity and cost, especially when collector layers are used to mitigate these issues.
Innovation Solution
The battery employs a structure where the active material is supported by a conductive matrix with an area ratio of active material to conductive material ranging from 20:80 to 65:35, eliminating the need for collector layers by using a single sub-layer electrode that functions as both active and collector, and is formed through a co-firing process to enhance conductivity and simplify manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a collector layer is stacked on an electrode layer to reduce electrode impedance, then electrical conductivity is improved, but the manufacturing process becomes complicated and production cost increases
Solution Approach 1:
The invention merges the electrode layer and collector layer into a single integrated layer. The electrode layer is formed by mixing active material with conductive material in specific proportions (volume ratio 20:80 to 65:35), creating a composite structure that simultaneously provides electrochemical activity and electrical conductivity, eliminating the need for a separate collector layer
Solution Approach 2:
The invention uses composite materials by combining active material (metal oxide or metal sulfide) with conductive material in the electrode layer. This composite structure provides both the electrochemical functionality of the active material and the electrical conductivity of the conductive material, resolving the contradiction between conductivity and manufacturing complexity
2Ease of manufacture
If many coating and drying processes are repeated to form multiple layers, then battery structure is achieved, but manufacturing yield decreases due to solvent damage to electrolyte layer
Solution Approach 1:
The invention reduces the number of coating and drying processes by merging the electrode layer and collector layer formation into a single coating process. The mixed slurry containing both active material and conductive material is coated in one step, followed by a single drying process, eliminating repeated exposure to solvents that would damage the electrolyte layer
Solution Approach 2:
The invention performs preliminary mixing of active material and conductive material in the slurry preparation stage, so that both components are uniformly distributed before coating. This preliminary action ensures that the final electrode layer has the desired conductivity and electrochemical properties without requiring subsequent processing steps
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 approach reduces electrode impedance, increases discharge capacity, and simplifies the manufacturing process, allowing for the use of previously difficult-to-adopt active materials while improving charge-discharge characteristics and reducing production costs.
Implementation Method 1
a structure where active material is supported by conductive matrix composed of conductive material
Implementation Method 2
co-firing process to enhance conductivity
Implementation Method 3
co-firing the laminate
Data Source
AI summary
In multilayer wholly solid lithium ion secondary batteries, a laminate having a collector layer of material with high conductivity superimposed on an active material layer has been disposed so as to attain a lowering of battery impedance. Consequently, in the fabrication of each of positive electrode layer and negative electrode layer, stacking of three layers consisting of an active material layer, a collector layer and an active material layer has been needed, thereby posing the problem of complex processing and high production cost. In the invention, a positive electrode layer and a negative electrode layer are fabricated from paste consisting of active material mixed with conductive substance in a given mixing ratio, and no collector layer is disposed. This realizes process simplification and manufacturing cost reduction without deterioration of battery performance and has also been effective in enhancing of battery performance, such as improvement to cycle characteristics.