Battery Electrode Insulating Layer for Crack-Free Adhesion
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Solution Overview
Problem
Secondary batteries face stability issues due to short circuits between positive and negative electrodes, particularly exacerbated by heat resistance limitations of traditional porous membranes used as separators, which can lead to thermal runaway.
Innovation Solution
An electrode with an insulating layer formed on the current collector, using a water-based binder and ceramic particles, applied in a specific solvent system to achieve desired surface characteristics that enhance adhesion and prevent cracks, thereby stabilizing the electrode assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polymer solution such as PVDF is coated and dried to form an insulating layer, then the insulating layer is formed on the current collector, but the polymer penetrates the inside of the active material layer after coating and before drying, making it difficult to form an insulating layer with appropriate performance
Solution Approach 1:
The patent changes the solvent parameter from conventional organic solvents to water as the main solvent component. This parameter change prevents polymer penetration into the active material layer because water-based solutions have different drying characteristics and lower solvent power compared to organic solvents like NMP or DMF, thereby enabling precise control over insulating layer formation while maintaining appropriate insulating performance
Solution Approach 2:
The patent uses a composite binder system comprising both water-soluble binder (such as carboxymethyl cellulose or styrene-butadiene rubber emulsion) and conventional polymer binder (PVDF). This composite approach allows the water-soluble binder to form a stable insulating layer structure that prevents polymer penetration, while the PVDF provides the necessary insulating properties and adhesion
2Manufacturing precision
If rapid drying is performed before the polymer penetrates the inside of the active material layer, then the insulating layer can be formed with better control, but the adhesion force of the formed insulating layer is lowered, reducing the performance of the insulating layer
Solution Approach 1:
The composite binder system comprising water-soluble binder and PVDF works synergistically: the water-soluble binder provides strong adhesion to the current collector and forms a stable matrix, while PVDF fills the matrix and provides insulating properties. This composite structure maintains high adhesion force even with rapid drying because the water-soluble binder component ensures strong bonding to the substrate
Solution Approach 2:
Changing to a water-based solvent system alters the drying kinetics and polymer-solvent interaction parameters. Water evaporates more rapidly than organic solvents but forms stronger hydrogen bonding networks that enhance adhesion. The patent optimizes the water content and drying conditions to achieve both rapid drying control and high adhesion force simultaneously
3Reliability
If traditional porous membrane separators are used, then the separator provides electrical insulation between electrodes, but the separator has insufficient heat resisting temperature and shrinks due to reaction heat during short circuit, causing thermal runaway
Solution Approach 1:
The patent forms a composite insulating layer on the current collector that combines organic polymer binder (PVDF) with inorganic ceramic particles (such as alumina, silica, or boehmite). This composite structure provides both electrical insulation from the polymer matrix and high heat resistance from the ceramic particles, which maintain structural stability at elevated temperatures and prevent separator shrinkage during thermal events
Solution Approach 2:
The insulating layer is applied specifically to the uncoated portions and boundary regions of the current collector where electrical insulation is most critical. The layer provides localized electrical insulation exactly where needed, while the ceramic particles distributed throughout the layer provide localized heat resistance at potential short-circuit points, addressing the thermal stability problem at the most vulnerable locations
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 provides an electrode with improved insulation properties and adhesion force, preventing cracks and ensuring stability even under abnormal conditions, thus enhancing the safety and performance of secondary batteries.
Implementation Method 1
an insulating layer formed on the current collector, using a water-based binder and ceramic particles, applied in a specific solvent system to achieve desired surface characteristics that enhance adhesion
Data Source
AI summary
The present application relates to an electrode, a manufacturing method thereof, and a use thereof. The present application can provide an electrode having an insulating layer that stably secures desired insulation properties, and simultaneously exhibits excellent adhesion force, and does not cause cracks or the like at the boundary between the coated portion and the uncoated portion of the electrode, and a manufacturing method thereof. In the present application, the use of the electrode can also be provided.