Dry Electrode Film With Super-Fibrillized Binder for Low ESR
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Solution Overview
Problem
Conventional energy storage device electrodes, particularly those for lithium ion capacitors, face challenges in achieving a balance between mechanical strength and electrical performance due to the thickness and binder loading of dry electrode films, leading to higher equivalent series resistance and increased volume occupation.
Innovation Solution
The development of a free-standing dry electrode film comprising super-fibrillized binder particles and carbon particles, fabricated through a dry process with reduced speed and increased pressure fibrillization, allows for thinner films with improved mechanical integrity and reduced binder loading, incorporating electrical conductivity promoting additives to decrease equivalent series resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional dry electrode films are used with standard thickness and binder loading, then mechanical strength is maintained, but equivalent series resistance increases and volume occupation increases
Solution Approach 1:
The patent changes the physical and chemical parameters of the binder material by applying super-fibrillization treatment, which transforms the binder into a highly fibrillized state with increased surface area and improved adhesion properties. This parameter change allows for reduced binder loading (3-7 wt%) while maintaining mechanical strength and reducing equivalent series resistance, as the fibrillized binder creates more contact points with carbon particles for both mechanical bonding and electrical conductivity.
2Strength
If binder loading is increased to improve mechanical strength, then electrode film integrity is maintained, but equivalent series resistance increases
Solution Approach 1:
The patent creates a composite structure where super-fibrillized binder particles are combined with conductive carbon particles in an optimized ratio. The fibrillized binder forms a three-dimensional network that simultaneously provides mechanical strength and electrical pathways, while the conductive carbon particles fill gaps and enhance conductivity. This composite approach allows reduced binder loading (3-7 wt%) without sacrificing mechanical integrity or increasing equivalent series resistance.
3Volume of stationary object
If electrode film thickness is reduced to decrease volume occupation, then power density improves, but mechanical stability may compromise
Solution Approach 1:
The patent successfully implements thin film technology by creating free-standing dry electrode films with thickness of 50-120 μm that maintain mechanical stability. The super-fibrillized binder creates a flexible yet strong matrix that can form stable thin films without requiring excessive binder loading or additional support structures. The fibrillized binder's high surface area and adhesion properties enable the thin film to maintain integrity while reducing volume occupation and improving power density.
4Object-generated harmful factors
If binder loading is reduced to decrease equivalent series resistance, then electrical performance improves, but mechanical strength decreases
Solution Approach 1:
The patent applies preliminary super-fibrillization treatment to the binder material before incorporating it into the electrode film. This preliminary action transforms the binder into a highly fibrillized state with enhanced adhesion and electrical properties. As a result, the pre-treated binder can maintain mechanical strength at lower loadings (3-7 wt%) while simultaneously reducing equivalent series resistance, because the fibrillized structure creates more contact points for both mechanical bonding and electrical conductivity pathways.
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 results in lithium ion capacitors with reduced thickness, lower equivalent series resistance, and enhanced power density, while maintaining mechanical stability, thereby facilitating cost-effective production and application in various vehicles.
Implementation Method 1
super-fibrillized binder particles; and a current collector
Implementation Method 2
dry carbon particles; and a current collector
Implementation Method 3
calendaring the super-fibrillized electrode film mixture to form a free-standing super-fibrillized electrode film
Data Source
AI summary
An energy storage device can include a cathode, an anode, and a separator between the cathode and the anode, where the anode and/or electrode includes an electrode film having a super-fibrillized binder material and carbon. The electrode film can have a reduced quantity of the binder material while maintaining desired mechanical and/or electrical properties. A process for fabricating the electrode film may include a fibrillization process using reduced speed and/or increased process pressure such that fibrillization of the binder material can be increased. The electrode film may include an electrical conductivity promoting additive to facilitate decreased equivalent series resistance performance. Increasing fibrillization of the binder material may facilitate formation of thinner electrode films, such as dry electrode films.