Crosslinked Polymer Binder for Secondary Battery Electrodes
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Solution Overview
Problem
Existing methods for removing metal foreign matter from acrylic acid polymers, particularly in powdered or solid forms, are insufficient in reducing metal contaminants, leading to increased viscosity and poor flex resistance in secondary battery electrodes due to the formation of crosslinked structures caused by metal ions.
Innovation Solution
A binder for secondary battery electrodes is developed, comprising a crosslinked polymer or salt with a carboxyl group, where the polyvalent metal ion content is limited to no more than 100 ppm and the number of metal particles between 10 μm and 100 μm per gram is no more than 10^3, ensuring effective removal of metal contaminants during the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If metal foreign matter is not removed from acrylic acid polymer, then the polymer can be used directly in electrode slurry, but the viscosity of electrode slurry increases and coating properties deteriorate due to crosslinked structure formation
Solution Approach 1:
The patent applies the extraction principle by removing metal foreign matter (metal ions and metal particles) from the acrylic acid polymer through specific purification processes. This extraction of harmful metal contaminants prevents crosslinking reactions, thereby maintaining low viscosity and good coating properties of the electrode slurry without requiring complex manufacturing modifications.
Solution Approach 2:
The patent applies parameter changes by controlling the metal ion content to 100 ppm or less and metal particle content to 10^3 or less per 1 g of polymer. By changing these critical parameters (metal contamination levels), the patent achieves the desired balance between ease of manufacture and coating quality, preventing excessive crosslinking while maintaining polymer functionality.
2Device complexity
If metal foreign matter is not removed from acrylic acid polymer, then the manufacturing process is simpler, but the flex resistance of the electrode decreases due to crosslinked structure formation
Solution Approach 1:
The patent removes metal foreign matter through purification processes including metal ion removal and metal particle filtration. This extraction maintains the polymer's flexibility by preventing excessive crosslinking, thereby improving flex resistance without requiring fundamentally different manufacturing processes.
Solution Approach 2:
The patent controls specific parameters (metal ion content ≤100 ppm, metal particle content ≤10^3 per g) to achieve the desired flex resistance. By adjusting these parameters within defined ranges, the patent maintains reliable electrode performance while keeping the manufacturing process relatively simple.
3Productivity
If metal foreign matter is not removed from acrylic acid polymer, then no additional processing steps are needed, but the electrode slurry shows poor dispersion of active material
Solution Approach 1:
The patent extracts metal foreign matter through purification steps that remove metal ions and particles from the polymer. This extraction prevents metal-induced aggregation and crosslinking, thereby maintaining uniform dispersion of active material in the electrode slurry without requiring fundamentally different processing approaches.
Solution Approach 2:
The patent controls metal contamination parameters (ions ≤100 ppm, particles ≤10^3 per g) to ensure stable dispersion characteristics. By maintaining these parameter thresholds, the patent achieves consistent composition stability while preserving relatively efficient processing.
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 suppresses the rise in viscosity and ensures excellent coating properties and flex resistance by minimizing metal crosslinks, resulting in improved electrode performance.
Implementation Method 1
removing metal particles from the crosslinked polymer
Data Source
AI summary
A secondary battery electrode has excellent characteristics. As a binder for a secondary battery electrode, a crosslinked polymer or salt thereof having a carboxyl group is used. The crosslinked polymer or salt includes 30 mass % or more and not more than 100 mass % of a structural unit derived from an ethylenically unsaturated carboxylic acid monomer and a metal ion content of the crosslinked polymer or salt thereof is not more than 100 ppm or less.