Non-aqueous Battery Slurry Viscosity Stabilization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing non-aqueous secondary battery electrode slurries exhibit significant viscosity variation with shear rate, leading to inconsistent electrode active material layer thickness and increased internal resistance, which affects the performance and stability of the battery.
Innovation Solution
A non-aqueous secondary battery electrode slurry comprising a binder polymer with specific structural units, a cellulose derivative, and a liquid medium, where the binder polymer includes components derived from aromatic ethylenically unsaturated compounds, nonionic (meth)acrylic acid esters, and anionic unsaturated compounds, along with a cellulose derivative having a controlled degree of etherification and molecular weight, to stabilize viscosity and enhance peel strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If components such as thickeners are added to improve dispersibility and adjust coating level, then the electrode slurry becomes more likely to behave as a non-Newtonian fluid, but the electrode slurry exhibits large viscosity change with respect to shear rate
Solution Approach 1:
The patent changes the chemical composition parameters of the binder polymer by specifying it must contain structural units derived from (meth)acrylic acid esters with particular glass transition temperatures and functional groups. This compositional parameter change allows the slurry to maintain stable viscosity across shear rates while achieving proper dispersibility, resolving the contradiction between ease of operation and composition stability.
Solution Approach 2:
The patent creates a composite binder system combining specific polymer types with controlled molecular weights and functional characteristics. The binder polymer is formulated as a composite material with multiple structural units including (meth)acrylic acid ester units and other functional units, achieving both good dispersibility and viscosity stability through material composition rather than adding separate thickener components.
2Stability of the object's composition
If the electrode slurry has high viscosity stability, then the thickness and surface condition of the electrode active material layer are stabilized, but the peel strength of the electrode active material layer with respect to the current collector must be maintained high
Solution Approach 1:
The patent optimizes the glass transition temperature parameter of the binder polymer to be within -50°C to 0°C, and controls the molecular weight and functional group composition. These parameter changes enable the binder to provide both viscosity stability during coating and high peel strength after drying, as the glass transition temperature range ensures appropriate binder flexibility and adhesion properties.
Solution Approach 2:
The patent introduces functional units with specific local properties into the binder polymer structure, including units with carboxyl groups, hydroxyl groups, or epoxy groups. These localized functional groups provide specific interaction sites that enhance adhesion to the current collector and active material particles, maintaining high peel strength while the overall polymer structure provides viscosity stability.
3Reliability
If the electrode slurry is designed to produce low internal resistance, then the battery performance is improved, but the manufacturing precision of the electrode active material layer thickness must be maintained
Solution Approach 1:
The patent controls the viscosity parameters of the electrode slurry through specific binder polymer selection, ensuring Newtonian fluid behavior with stable viscosity across shear rates. This viscosity control, combined with optimized solid content and molecular weight parameters, enables uniform coating thickness while the binder composition ensures low internal resistance through good electrical conductivity and contact between active material particles.
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 solution stabilizes viscosity against shear rate changes, enables high peel strength of the electrode active material layer, and reduces internal resistance, resulting in improved battery performance and stability.
Implementation Method 1
at least a portion of the cellulose derivative (B) is dissolved in the liquid medium (D)
Implementation Method 2
The binder functions both to bind active materials together and to adhere the active materials to the current collector
Implementation Method 3
The electrode active material is a material capable of intercalating and deintercalating ions that serve as charge carriers
Data Source
Figure 1
Figure 2
AI summary
A non-aqueous secondary battery electrode slurry includes a binder polymer (A), a cellulose derivative (B), an electrode active material (C), and a liquid medium (D), in which the binder polymer (A) has a first structural unit derived from an aromatic ethylenically unsaturated compound (a1) which is a nonionic aromatic compound having one independent ethylenically unsaturated bond; the cellulose derivative (B) has a degree of etherification from 0.50 to 1.2 and a weight average molecular weight from 100,000 to 700,000; and at least a portion of the cellulose derivative (B) is dissolved in the liquid medium (D).