Electrode Insulating Layer for Thermal Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium ion secondary batteries face safety issues due to the use of polyolefin-based separators, which can melt or shrink at high temperatures, leading to a risk of explosion from short circuits between the cathode and anode.
Innovation Solution
A method for manufacturing an electrode structure with an insulating layer made from inorganic particles and a binder, where the slurry is coated, dried, and thermo-compressed onto an electrode active material layer, forming a stable and porous structure that replaces the traditional separator, enhancing adhesion and dimensional stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polyolefin-based separator is used to prevent short circuits, then the battery can function normally, but the separator melts or shrinks at high temperatures causing safety risks
Solution Approach 1:
The patent changes the material parameters of the separator by using inorganic particles (such as alumina, silica, or boehmite) with high melting points instead of polyolefin materials. This parameter change enables the separator to maintain its structural integrity at temperatures above 200°C, preventing the melting and shrinking issues that occur with conventional polyolefin separators during thermal runaway events.
Solution Approach 2:
The patent creates a composite separator structure by forming an insulating layer composed of inorganic particles dispersed in a binder polymer matrix on the electrode surface. This composite material combines the high-temperature stability of inorganic particles with the flexibility and processability of the polymer binder, achieving both thermal stability and functional performance.
2Object-affected harmful factors
If an inorganic particle-based insulating layer is formed on the electrode, then thermal stability is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The patent merges the separator formation process with the electrode manufacturing process by applying the insulating layer directly onto the electrode surface during the same manufacturing sequence. The slurry containing inorganic particles and binder is coated, dried, and thermo-compressed in an integrated process, eliminating the need for separate separator assembly steps and reducing overall manufacturing complexity.
Solution Approach 2:
The insulating layer is applied directly to the electrode surface, making the electrode structure itself provide the separator function. This self-service approach eliminates the need for separate separator components and their associated handling, assembly, and processing steps, thereby simplifying the overall manufacturing process despite the advanced material composition.
3Strength
If the insulating layer slurry is dried before transfer, then adhesion is improved, but the manufacturing time increases
Solution Approach 1:
The patent performs preliminary drying of the insulating layer slurry on the electrode surface before transfer to achieve optimal adhesion. By drying the slurry in place first, the binder polymer can properly adhere to the electrode surface, creating a strong bond that prevents delamination during subsequent handling and battery assembly operations.
Solution Approach 2:
The patent replaces conventional drying methods with thermal field application, using controlled heating to evaporate the solvent from the slurry. This thermal substitution of mechanical drying processes enables more efficient and uniform drying, improving adhesion while managing the time requirement through controlled thermal 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
The solution simplifies the electrode manufacturing process, improves structural stability, increases wettability with electrolyte solutions, and reduces the risk of shrinkage and melting, thereby enhancing the safety and performance of lithium ion secondary batteries.
Implementation Method 1
drying a slurry for an electrode active material layer including an electrode active material, a binder and a solvent on an electrode current collector placed on a heated bottom surface whose temperature is from 40 to 200°C; coating and drying a slurry for an electrically insulating porous layer including inorganic particles, a binder, and a solvent, on a heated roller
Implementation Method 2
transferring the dried slurry for an electrically insulating porous layer to the dried slurry for an electrode active material layer on the bottom surface, and thermo-compressing simultaneously between the heated roller and the heated bottom surface the dried slurry for an electrically insulating porous layer and the dried slurry for an electrode active material layer
Data Source
AI summary
Disclosed is a method for manufacturing an electrode structure including (S1) coating and drying a slurry for an electrode active material layer on an electrode current collector placed on a heated bottom surface, (S2) coating and drying a slurry for an insulating layer including inorganic particles, a binder, and a solvent, on a heated roller located at a predetermined distance from the bottom surface, and (S3) transferring the dried slurry for an insulating layer to the dried slurry for an electrode active material layer on the bottom surface, and thermo-compressing the dried slurry for an insulating layer and the dried slurry for an electrode active material layer, to form an insulating layer on an electrode surface. The manufacturing method may simplify an electrode forming process, provide a pore structure formed by the integrated connection of the electrode active material and the insulating layer, and achieve stronger structural stability by improved binding of the electrode active material layer and the insulating layer.