Dry Electrode Binder Composition for Strong Solvent-Free Battery Sheets
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Solution Overview
Problem
Existing lithium secondary battery manufacturing methods face issues such as solvent evaporation defects leading to pinholes and cracks, non-uniform drying causing particle migration, and high manufacturing costs due to expensive drying devices, while dry electrode methods lack sufficient tensile strength and are cost-inefficient.
Innovation Solution
A dry electrode composition using a fiberizable binder and plasticizer, combined with calendering and kneading processes, to create a binder that forms fibrous bundles, enhancing tensile strength and eliminating the need for solvent drying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a solvent-based electrode slurry drying process is used, then the electrode mixture layer can be formed, but pinholes and cracks occur due to solvent evaporation defects
Solution Approach 1:
The invention extracts and eliminates the solvent from the electrode manufacturing process entirely. By using a dry electrode mixture without solvent, the harmful evaporation process is removed, preventing pinholes and cracks while maintaining electrode quality.
Solution Approach 2:
The invention changes the fundamental parameter of the electrode mixture from wet (solvent-based) to dry (solvent-free). This parameter change eliminates the evaporation process and its associated defects, while the binder composition ensures proper adhesion and structural integrity.
2Manufacturing precision
If a solvent-based electrode slurry drying process is used, then the electrode mixture layer can be formed, but particle migration occurs due to non-uniform drying
Solution Approach 1:
The invention removes the solvent and its evaporation process from the system. Without solvent evaporation, there is no driving force for particle migration, ensuring uniform particle distribution throughout the electrode mixture layer.
3Manufacturing precision
If expensive drying devices are used to evenly dry the electrode mixture layer, then uniform drying can be achieved, but manufacturing cost and operation time increase significantly
Solution Approach 1:
The invention extracts and eliminates the entire drying process and associated expensive drying devices. By using a solvent-free dry electrode mixture, uniform drying is no longer needed as there is no solvent to evaporate, significantly reducing manufacturing cost and simplifying the process.
4Ease of manufacture
If a dry electrode manufacturing method without solvent is used, then manufacturing cost is reduced and processability is improved, but tensile strength is insufficient and sheet shape cannot be maintained
Solution Approach 1:
The invention uses a composite binder system comprising multiple components (polyvinylidene fluoride, carboxymethyl cellulose, and starch) in specific ratios. This composite binder provides sufficient tensile strength and adhesion to maintain electrode sheet shape while enabling dry manufacturing without solvent.
Solution Approach 2:
The invention optimizes the binder composition parameters and ratios to achieve the required mechanical properties. By carefully selecting and combining different binder materials in specific proportions, the dry electrode mixture achieves adequate tensile strength for sheet formation and handling.
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 method produces electrodes with improved tensile strength and reduced manufacturing costs by omitting solvent drying, maintaining sheet shape and reducing facility investment.
Implementation Method 1
a particulate binder in which fibers aggregate to form bundles; the binder is fiberizable by heat or pressure
Implementation Method 2
the binder is fiberizable by heat or pressure
Implementation Method 3
the binder is fiberizable by heat or pressure
Data Source
AI summary
A dry electrode composition including: an electrode active material; a particulate binder in which fibers aggregate to form bundles; and a plasticizer, wherein the binder is fiberizable by heat and pressure, a method for manufacturing a dry electrode sheet for a secondary battery using the dry electrode composition, and an electrode and a secondary battery including the dry electrode sheet are provided.