Thermoresponsive Paste Coating for Li-Ion Battery Electrodes
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Solution Overview
Problem
The production of lithium-ion battery electrodes faces challenges such as binder migration during drying, leading to poor adhesion and electrochemical performance, especially with rapid drying methods, and issues with inhomogeneous surface weights and particle alignment due to low solids content and anisotropic particle shapes.
Innovation Solution
A thermoresponsive paste is developed by adding a solidifying additive, such as methyl cellulose, to conventional pastes, which suppresses binder migration and enhances particle alignment and homogeneity, allowing for faster and more efficient drying without compromising adhesion or particle orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If rapid drying is used to increase productivity, then drying speed is improved, but binder migration occurs leading to poor adhesion
Solution Approach 1:
The invention changes the physical-chemical parameters of the paste by adding a solidifying agent, transforming it into a thermoresponsive paste that solidifies at elevated temperatures. This allows rapid drying without binder migration because the solidified matrix prevents particle movement even under strong convective conditions.
Solution Approach 2:
The solidifying agent is added to the paste before application, so that upon heating during drying, the paste pre-solidifies forming a stable matrix that locks particles in place. This preliminary structural change prevents the harmful binder migration that would otherwise occur during rapid drying.
2Ease of operation
If low solids content paste is used to maintain flowability, then application is improved, but convection during drying causes particle migration and inhomogeneous surface weight
Solution Approach 1:
The paste's rheological parameters are changed by incorporating a solidifying agent that triggers gelation at processing temperatures. This creates a thermoresponsive system that remains flowable during application but solidifies during drying, preventing convection-driven particle migration while maintaining application ease.
Solution Approach 2:
The invention introduces dynamic rheological properties to the paste through the solidifying agent. The paste transitions from a flowable state during application to a solidified state during drying, allowing the system to adapt its properties to different process stages and eliminate surface weight inhomogeneity.
3Reliability
If vertical particle alignment is achieved to improve charging speed, then battery performance is improved, but drying convection disrupts alignment and causes crack formation
Solution Approach 1:
The invention changes the thermal-rheological parameters of the paste by adding a solidifying agent that triggers rapid solidification at drying temperatures. This solidified matrix stabilizes the vertically aligned particles, preventing convection-induced disruption and crack formation while preserving the high-performance aligned structure.
Solution Approach 2:
The solidifying agent provides beforehand cushioning by creating a rigidified matrix that protects the carefully aligned particle structure from convective disturbances during drying. This pre-established structural support prevents both alignment loss and crack formation.
4Reliability
If mild drying conditions are used to prevent binder migration, then adhesion is improved, but manufacturing productivity decreases
Solution Approach 1:
The invention fundamentally changes the paste's thermal response by adding a solidifying agent, enabling it to withstand rapid drying conditions. This allows the system to achieve both high productivity through fast drying and high reliability through prevented binder migration, eliminating the need for mild drying conditions.
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 thermoresponsive pastes results in improved adhesion, homogeneous basis weights, and maintained particle alignment, accelerating the electrode manufacturing process while preventing defects like cracks and inhomogeneities, even with low solids content and anisotropic particles.
Implementation Method 1
a thermoresponsive paste which contains solid particles and a thermoresponsive component... the coating or layer is applied to a support, solidified and dried
Implementation Method 2
At least 0.001% and less than 80% of a volatile component is removed from the coating during solidification
Data Source
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AI summary
The invention relates to a method for producing a coating, which can be used in particular to produce electrodes, in particular to produce electrodes for use in lithium ion batteries. A method for producing a coating from a thermoresponsive paste, which contains solid particles and a thermoresponsive component, the coating or layer being applied to substrate, solidified and dried, characterized in that less than 80% of a volatile solvent component is removed from the coating during the solidification.