Dry Powder Electrode Injection for Battery Manufacturing
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Solution Overview
Problem
Conventional energy storage device electrode manufacturing processes require high binder content to form strong bonds, leading to reduced energy density, increased electrical resistance, and the need for solvent recovery systems, which are costly and environmentally harmful.
Innovation Solution
A method involving a conductive current collector with a primer layer and injecting dry powder electrode materials into the primer layer to form an electrode film, eliminating the need for solvents and reducing binder usage while maintaining strong particle-to-particle and particle-to-collector bonds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a high percentage of binder is used to form strong bonds between powder particles and current collector, then bonding strength is improved, but energy density is reduced due to less active material and increased electrical resistance
Solution Approach 1:
The patent divides the binder function into two separate layers: a primer layer that provides particle-to-particle bonding, and a coating layer that provides particle-to-collector bonding. This segmentation allows each layer to use optimized binder amounts for its specific function, eliminating the need for excessive binder in a single layer and increasing active material content for higher energy density.
Solution Approach 2:
The patent extracts the particle-to-particle bonding function from the coating layer and places it in a separate primer layer. This extraction allows the coating layer to focus on particle-to-collector bonding with minimal binder, while the primer layer handles particle aggregation with appropriate binder content, overall reducing total binder usage and increasing energy density.
2Strength
If a high percentage of binder is used to bond powder particles to metal current collector, then bonding strength is improved, but electrical resistance increases due to blocked electrical flow between active material particles
Solution Approach 1:
The patent segments the bonding functions into two layers: the primer layer handles particle-to-particle bonding with conductive carbon, and the coating layer handles particle-to-collector bonding. This segmentation ensures that the coating layer has minimal binder to maintain electrical continuity, while the primer layer provides structural bonding, thereby reducing overall electrical resistance.
Solution Approach 2:
The patent uses composite material structure with conductive carbon particles mixed with binder in the primer layer to create a conductive network for particle-to-particle bonding. This composite approach maintains electrical pathways while providing mechanical bonding strength, reducing electrical resistance without sacrificing bonding strength.
3Ease of manufacture
If conventional slurry coating process with solvent drying is used, then electrode manufacturing is achieved, but manufacturing cost increases due to solvent recovery systems and energy consumption
Solution Approach 1:
The patent extracts the solvent drying step from the manufacturing process by using a dry powder coating method. The binder is applied as a dry powder that adheres to particles without requiring solvent evaporation, eliminating the need for energy-intensive drying ovens and expensive solvent recovery systems, thereby reducing manufacturing cost and complexity.
Solution Approach 2:
The patent uses a disposable dry powder coating approach where the binder is applied as a fine powder that adheres to particles and is then lightly pressed. This method eliminates the need for expensive, complex solvent recovery systems and high-energy drying processes, using instead a simple, low-cost dry application method that reduces manufacturing complexity and cost.
4Loss of substance
If conventional slurry coating process with long drying time is used, then solvent removal is achieved, but production time increases significantly
Solution Approach 1:
The patent extracts the solvent removal step entirely from the process by using a dry powder coating method. The binder is applied as a dry powder that adheres to particles through adhesion and is then lightly pressed into place, eliminating the need for long drying times and high-temperature ovens, thereby significantly reducing production time.
Solution Approach 2:
The patent skips the entire solvent evaporation and drying step by using a dry powder application method. The binder powder is applied and lightly pressed onto the particles, achieving adequate bonding without the time-consuming drying process, thus rushing through what would traditionally be a lengthy manufacturing step.
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 binder content, eliminates the need for solvent recovery systems, and shortens the drying process, resulting in more efficient and cost-effective electrode production with improved energy and power densities.
Implementation Method 1
a binder, for example polyvinylidene fluoride (PVDF), is pre-dissolved in a solvent to form the binder solution... in order to form strong bonds between the powder particles and between the powder particles to the metal current collector
Implementation Method 2
The slurry is then coated onto a current collector by a cylindrical roller
Implementation Method 3
The current collector along with the coating layer is passed through a long dryer, where the solvent is dried and removed from the electrode... drying time for electrodes produced by conventional coating processes can take 12-24 hours at 120° C
Data Source
AI summary
A method for producing an electrode for an energy storage device includes: forming a current collector from a conductive material; forming a primer layer on the current collector; injecting dry powder electrode materials into the primer layer, wherein the dry powder electrode materials injected into the primer layer form an electrode film in electrical contact with the current collector.