Free-Standing Electrode Film via Water-Based Binder Activation
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Solution Overview
Problem
Conventional methods for manufacturing electrodes for energy storage devices face issues such as reduced energy and power density due to binder interference, residual solvent, high manufacturing costs, and short device life, primarily because of the use of solvents like N-methylpyrrolidine and the need for extensive drying processes.
Innovation Solution
A method involving a flexible binder activated by certain additives, mixed with active and conductive materials using high-speed mixing, forming a free-standing electrode film with minimal solvent usage and vaporizable solvents to reduce residue and drying energy, resulting in higher packing density and lower binder content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional coating or extrusion methods are used with solvents like NMP, then the electrode can be formed with binder, but residual solvent remains in the electrode causing chemical reactions that harm device reliability and shorten field life
Solution Approach 1:
The patent changes the solvent parameter from conventional NMP to water, which has different evaporation characteristics and does not cause harmful chemical reactions. This parameter change eliminates residual solvent issues while maintaining the electrode formation process
Solution Approach 2:
The patent uses water as a temporary solvent that completely evaporates without residue, replacing persistent organic solvents. The water serves its purpose during manufacturing then disappears completely, leaving no harmful residues in the final product
2Reliability
If extensive drying processes are used to remove solvent, then residual solvent is reduced, but manufacturing costs increase and energy consumption rises
Solution Approach 1:
The patent changes the solvent's physical parameter (boiling point and evaporation rate) from NMP to water. Water's higher volatility allows for simpler, lower-energy drying processes while achieving complete solvent removal
Solution Approach 2:
The patent extracts the harmful drying energy requirement by using water as solvent, which can be removed with minimal energy input compared to NMP. The drying process becomes a simple evaporation step rather than an energy-intensive extraction process
3Strength
If binder content is increased to strengthen the electrode, then electrode strength improves, but energy and power density decrease due to more non-functional materials
Solution Approach 1:
The patent changes the binder's chemical parameter from solvent-dependent to water-based activation. This allows the binder to achieve adequate adhesion at lower concentrations, reducing the volume of non-functional material in the electrode
Solution Approach 2:
The water-based binder system provides self-adhesion properties that reduce the need for excessive binder material. The binder activates and bonds particles effectively at lower concentrations, serving the strengthening function with minimal material
4Quantity of substance
If packing density is increased to improve energy density, then more active material per volume is achieved, but electrical conductivity may decrease due to reduced contact between particles
Solution Approach 1:
The patent changes the binder's physical parameter (viscosity and adhesion characteristics) through water-based formulation. This allows the binder to effectively bridge particles at higher packing densities, maintaining electrical contact pathways even when particles are more tightly packed
Solution Approach 2:
The water-based binder acts as an effective intermediary material that maintains electrical conductivity pathways between densely packed active material particles. The binder's properties enable it to function as a conductive bridge even at minimal concentrations
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 significantly enhances energy and power density, extends device life, reduces manufacturing costs, and improves electrical conductivity, achieving greater than 10% and 25% increases in energy output compared to prior art methods.
Implementation Method 1
mixed with active and conductive materials using high-speed mixing
Implementation Method 2
vaporizable solvents to reduce residue and drying energy
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The present invention is directed to an electrode for energy storage devices and a method for making the electrode for energy storage devices (40) is disclosed, where a flexible binder in the electrode formulation is activated by certain additives and is uniformly deposited on to the active and conductive particles (44) by high speed mixing. The particles deposited with activated binder particles (42) are then pressed together to form a free standing electrode film. High performance and cost effective products, such as free standing electrode films, laminated electrodes, ultracapacitors, lithium ion capacitors, batteries, fuel cells and hybrid cells which are the combination of the above devices, and the energy storage system or the system blocks, such as modules, can be manufactured using this process.