Electrode Body Manufacturing via Binder Expansion for Adhesion
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Solution Overview
Problem
The existing method for manufacturing lithium-ion secondary batteries results in insufficient adhesion between the solid electrolyte sheet and the active material sheets, leading to increased internal resistance.
Innovation Solution
A method involving the formation of electrode and electrolyte layers by dispersing active materials and electrolytes with binders into solvents, applying the slurries onto base materials, and removing solvents to enhance adhesion through binder expansion and subsequent drying, which improves the bonding between the layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the lithium battery is manufactured through the process of laminating the active material sheets and the solid electrolyte sheet formed by the heat-drying and the peeling, and then hot-pressing the laminated body thus obtained, then the thickness of the sheet can be adjusted to a desired thickness, but there will be insufficient adhesion between the solid electrolyte sheet and the active material sheets, leading to increased internal resistance
Solution Approach 1:
The patent introduces a binder as an intermediary substance between the solid electrolyte and active material. The binder forms a slurry that is applied to the solid electrolyte sheet before laminating with active material sheets. This binder layer acts as a mediator that enhances interfacial adhesion and reduces internal resistance, resolving the contradiction between thickness control and layer adhesion.
Solution Approach 2:
The patent changes the physical and chemical parameters of the interface between solid electrolyte and active material by introducing a binder slurry with specific composition and viscosity. The binder undergoes drying and hot-pressing processes that modify its properties to optimize adhesion. This parameter change approach allows maintaining desired sheet thickness while significantly improving interlayer adhesion and reducing internal resistance.
2Reliability
If a liquid electrolytic solution is used, then it easily permeates into the cathode layer and anode layer to form interfaces with active materials, improving battery performance, but since commonly used electrolytic solutions are flammable, it is necessary to mount a system to ensure safety
Solution Approach 1:
The patent changes the physical state of the electrolyte from liquid to solid, thereby eliminating flammability while maintaining ion conductivity. The solid electrolyte is processed into a sheet form with controlled thickness and porosity to enable effective contact with active materials, achieving safety without sacrificing performance.
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 method reduces internal resistance by enhancing the adhesion between the electrode and electrolyte layers, resulting in improved lithium-ion conduction and increased discharge capacity.
Implementation Method 1
the binder contained in the electrode layer absorbs the solvent contained in the electrolyte slurry and expands
Implementation Method 2
removing the solvent contained in the electrode layer by drying the electrode layer
Data Source
AI summary
A method of manufacturing an electrode body having a pair of electrode layers and an electrolyte layer disposed between the pair of electrode layers, by which an electrode body with reduced internal resistance can be manufactured, the method including the steps of: dispersing at least an active material capable of releasing or absorbing and releasing a metal ion, an electrolyte having conductivity for the metal ion, and a binder into a solvent, to prepare an electrode slurry, and applying the electrode slurry onto a base material, thereby forming a sheet-shaped electrode layer containing the binder; and dispersing at least an electrolyte having ion conductivity for the metal ion into a solvent to prepare an electrolyte slurry, and applying the electrolyte slurry onto the electrode layer, thereby forming a sheet-shaped electrolyte layer on the electrode layer.