Positive Electrode Binder Composition for Adhesion and Slurry Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing positive electrodes for non-aqueous electrolyte secondary batteries face challenges in achieving both sufficient adhesion and stability of the electrode mixture slurry, particularly when using binders with high weight average molecular weights, which can lead to increased variance in battery characteristics.
Innovation Solution
A positive electrode with a binder having a weight average molecular weight of 1,300,000 or more, where the particle size distribution of D90-D10 is 100 μm or more, is used to improve adhesion and stability, allowing for a higher content of active material and reduced variance in battery characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a binder with high weight average molecular weight is used, then adhesion is improved, but slurry stability deteriorates
Solution Approach 1:
The patent changes the molecular weight parameter of the binder to 1,300,000 or more, which is higher than conventional binders. This parameter change enables the binder to provide sufficient adhesion while maintaining slurry stability, resolving the contradiction between improved adhesion and deteriorated slurry stability
Solution Approach 2:
The patent uses a composite approach by combining a high molecular weight binder (≥1,300,000) with specific particle size distribution (D90-D10≥100 μm) and controls the binder content within 3-15 mass% relative to active material. This composite material strategy achieves both strong adhesion and stable slurry properties
2Quantity of substance
If the amount of binder is decreased, then active material content is increased, but adhesion becomes insufficient
Solution Approach 1:
The patent changes the molecular weight parameter of the binder to 1,300,000 or more, which dramatically improves adhesion performance per unit mass. This allows the binder content to be reduced to 3-15 mass% while still achieving sufficient adhesion, thereby increasing active material content without sacrificing bonding strength
Solution Approach 2:
The patent uses a small amount of high-performance binder (3-15 mass%) that acts as an efficient adhesive, replacing the need for larger amounts of conventional lower molecular weight binders. This approach maximizes active material content while maintaining adequate adhesion
3Strength
If a binder with large weight average molecular weight is used, then adhesion is sufficient with small amount, but battery characteristic variance increases
Solution Approach 1:
The patent precisely controls the molecular weight parameter at 1,300,000 or more and the particle size distribution (D90-D10≥100 μm), which ensures consistent adhesion performance and slurry stability across production batches, thereby reducing battery characteristic variance
Solution Approach 2:
The patent optimizes the local properties of the binder by controlling both molecular weight (≥1,300,000) and particle size distribution (D90-D10≥100 μm). This localized quality control ensures uniform adhesion and slurry behavior, preventing excessive variance in battery characteristics
Data Source
AI summary
The present invention provides a positive electrode for nonaqueous electrolyte secondary batteries, the positive electrode having improved adhesion, while suppressing variation in battery characteristics. A positive electrode for nonaqueous electrolyte secondary batteries according to one embodiment of the present disclosure comprises a positive electrode collector and a positive electrode mixture layer that is formed on the surface of the positive electrode collector; the positive electrode mixture layer contains a positive electrode active material, a conductive agent and a binder; the weight average molecular weight of the binder is 1,300,000 or more; and D10 and D90 in the particle size distribution of the binder satisfy (D90-D10)≥100 μm.