Battery Electrode NMP Composition Using Controlled Solvent Impurities
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Solution Overview
Problem
Current battery electrode manufacturing processes require high-purity N-methylpyrrolidone (NMP) solvents, often resulting in costly purification or solvent wastage, and existing recycling methods fail to achieve the necessary 99% purity, leading to suboptimal electrode quality and increased electrical resistance.
Innovation Solution
A composition comprising NMP with impurities such as γ-butyrolactam or γ-butyrolactone, present in mass proportions between 0.01% and 19%, is used as a solvent for battery electrodes, allowing for improved dispersion and stability without the need for purification, reducing electrical resistance, and simplifying the formulation by reducing the amount of dispersing polymer and binder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-purity NMP (99% or more) is used in electrode manufacturing, then electrode quality and electrical conductivity are improved, but purification costs and solvent waste increase
Solution Approach 1:
The patent converts the harmful impurities (γ-butyrolactam and γ-butyrolactone) recovered from solvent evaporation into beneficial components that improve electrode performance. These impurities, which were previously discarded as waste, actually enhance carbon distribution and reduce electrical resistance when retained at controlled levels (0.01-19% each) in the NMP solvent composition.
Solution Approach 2:
The patent changes the purity parameter of NMP from the conventional 99% or higher to a controlled range of 80-98.99%, allowing specific impurities to be present within defined limits. This parameter modification eliminates the need for costly purification while maintaining or even improving electrode quality through the beneficial effects of controlled impurity levels.
2Manufacturing precision
If NMP is purified to 99% purity through distillation, then solvent quality is improved, but industrial cost increases
Solution Approach 1:
Instead of achieving complete purification to 99% or higher purity, the patent applies partial purification that retains controlled amounts of beneficial impurities. This partial action approach eliminates the need for multiple distillation steps while maintaining sufficient solvent quality for electrode manufacturing, thereby reducing industrial costs.
Solution Approach 2:
The patent transforms the waste impurities from the solvent recovery process into valuable components that enhance electrode performance. By retaining γ-butyrolactam and γ-butyrolactone within specific concentration ranges, the patent converts what would be harmful contaminants into beneficial additives that improve carbon distribution and electrical conductivity.
3Ease of manufacture
If recovered NMP solvent is used without purification, then cost is reduced, but electrode quality and electrical resistance deteriorate
Solution Approach 1:
The patent modifies the purity parameter from the conventional requirement of 99% or higher to a controlled range of 80-98.99%, allowing specific impurities to be present within defined limits (0.01-19% each for γ-butyrolactam and γ-butyrolactone). This parameter change enables the use of recovered solvent without costly purification while maintaining or improving electrode quality.
Solution Approach 2:
The patent converts the impurities that would normally deteriorate electrode quality into beneficial components. The γ-butyrolactam and γ-butyrolactone species, when present at controlled levels, act as effective dispersants and improve carbon distribution in the electrode, thereby enhancing electrical conductivity rather than deteriorating it.
4Ease of repair
If conventional solvent recovery methods are used, then solvent recycling is achieved, but purity requirements cannot be met
Solution Approach 1:
The patent changes the purity specification from 99% or higher to 80-98.99%, with controlled levels of specific impurities (0.01-19% each for γ-butyrolactam and γ-butyrolactone). This parameter modification enables solvent recycling through simple evaporation without requiring complex purification processes, while still meeting electrode manufacturing quality requirements.
Solution Approach 2:
The patent transforms the limitation of conventional solvent recovery (inability to achieve 99% purity) into an advantage by demonstrating that the recovered solvent with 80-98.99% purity and controlled impurities actually produces superior electrodes. The impurities that prevent high-purity recovery become beneficial additives that enhance electrode 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
The use of this impure NMP solvent improves the quality and stability of battery electrodes by enhancing carbon distribution, reducing electrical resistivity, and allowing for the reuse of solvent vapors from the manufacturing process, resulting in more efficient and cost-effective electrode production.
Implementation Method 1
NMP for its suitable properties (the capacity for dissolving the polymeric binder...)
Implementation Method 2
The solvent is subsequently evaporated off to obtain the electrode
Data Source
AI summary
The present invention relates to a composition for battery electrodes in which at least one solvent is a composition comprising between 80% and 95% by mass of N-methylpyrrolidone (NMP).