Dry Electrode Film Particle Sizing for Stronger Battery Assembly
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Solution Overview
Problem
Current methods for producing dry electrodes for energy storage devices face challenges in achieving the required mechanical strength and thickness, leading to incomplete assembly and reduced device performance.
Innovation Solution
A dry film manufacturing process involving a powder mixture of active materials and fibrillatable binders, subjected to shear force for fibrillation, then hot roll-pressed into a free-standing film, which is trimmed, wound, and laminated onto a current collector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If dry electrode films are produced using conventional dry methods, then the manufacturing process avoids solvents and drying ovens, but the resulting films do not achieve the required mechanical strength and thickness
Solution Approach 1:
The patent changes the particle size parameter of the active material from conventional fine particles to coarser particles in the range of 10-50 micrometers. This parameter change enables the formation of films with adequate mechanical strength and thickness while maintaining the dry manufacturing process advantages, resolving the contradiction between ease of manufacture and film strength
Solution Approach 2:
The patent uses a composite binder system comprising both PTFE (polytetrafluoroethylene) and PVDF (polyvinylidene fluoride) binders. This composite binder material provides superior mechanical properties and film integrity compared to single-binder systems, enabling the dry electrode film to achieve required strength without compromising manufacturing simplicity
2Reliability
If finer particle sizes are used in electrode materials, then the electrochemical performance improves, but the film mechanical strength and thickness requirements cannot be met
Solution Approach 1:
The patent optimizes the particle size parameter to a specific range of 10-50 micrometers, which balances electrochemical performance with mechanical film integrity. This parameter optimization allows the film to achieve both adequate thickness for handling and sufficient mechanical strength, while maintaining acceptable electrochemical performance
Solution Approach 2:
The patent applies local quality by using coarser particles (10-50 micrometers) that provide structural integrity and thickness, while the fibrillated binder material provides local bonding strength at particle interfaces. This localized functional distribution allows the film to meet both thickness control requirements and electrochemical performance standards
3Quantity of substance
If thinner electrode films are produced, then the energy density improves, but the mechanical strength and assembly completeness deteriorate
Solution Approach 1:
The patent changes the particle size parameter to coarser 10-50 micrometer particles, which enables the production of thinner films with adequate mechanical strength. The coarser particles provide structural framework that maintains film integrity at reduced thickness, allowing higher energy density while ensuring assembly completeness
Solution Approach 2:
The dual-binder composite system (PTFE + PVDF) provides enhanced mechanical properties that enable thinner film production. The composite binder structure maintains film integrity and adhesion even when film thickness is reduced, ensuring assembly completeness while improving energy density
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
The process results in dry electrode films with superior mechanical and electrochemical performance characteristics, enabling the production of robust and efficient energy storage devices.
Implementation Method 1
the binder material can be fibrillated by undergoing a shearing process
Implementation Method 2
The powder mixture is subjected to a shear force in order to be fibrillated
Implementation Method 3
The fibrillated mixture is hot roll-pressed into a free-standing film
Implementation Method 4
The fibrillated mixture is hot roll-pressed into a free-standing film
Implementation Method 5
the film is cooled immediately after coming out of the hot-press rollers
Implementation Method 6
the dry film is pressed and bound to a first side of a current collector foil to form a laminated electrode
Data Source
AI summary
Electrical energy storage devices made using a wet electrode application technique are associated with high energy consumption. Herein, a dry electrode or electrolyte application process involves mixing active material with a binder and then fibrillating the mixture. During preparation of the mixture, the smallest particles are removed to improve binding. The mixture is roll-pressed into a film, which is then actively cooled. Optionally, tension in the cooled portion of the film is increased for spooling the film. The film is adhered to a pre-treated current collector and then wound into a jelly roll for the manufacture of an electrical energy storage device.