Electrode-Integrated Separator With Porous Adhesive Pattern Bonding
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Solution Overview
Problem
Conventional lithium ion secondary battery separators face issues with insufficient adhesion to electrodes, thermal instability, and low mechanical strength, leading to partial detachment, wrinkles, and increased risk of internal short circuits.
Innovation Solution
An electrode-integrated separator design featuring an electrode active material layer with an adhesive portion pattern and a porous layer tightly bonded through the pattern, comprising a polymer binder and inorganic fine particles, ensuring strong bonding durability without impairing ionic conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a separator comprising a separator substrate and an inorganic coating layer is used, then thermal stability is improved, but adhesive force between separator and electrode becomes insufficient
Solution Approach 1:
The invention uses a composite structure combining a polyolefin separator substrate with an inorganic coating layer, and further integrates electrode active material layers directly on the inorganic coating. This multi-layer composite approach allows the polyolefin substrate to provide thermal stability while the inorganic coating and electrode material integration enhance adhesive force to electrodes, resolving the contradiction between thermal stability and adhesion.
2Temperature
If only an inorganic coating film is used as separator, then thermal stability is improved, but adhesive force with electrodes remains insufficient and insulating properties become extremely low
Solution Approach 1:
The invention creates a composite structure where the inorganic coating layer is integrated with electrode active material layers. The inorganic coating provides thermal stability, while the electrode active material layers restore insulating properties by maintaining proper electrical isolation between electrodes. The polyolefin substrate further supports the structure and enhances adhesion.
Solution Approach 2:
The inorganic coating layer serves multiple functions simultaneously: it provides thermal stability, enhances adhesive force to electrodes, and when integrated with electrode active materials, maintains insulating properties. This multi-functional design resolves the contradiction between thermal stability and insulating properties.
3Temperature
If only an inorganic coating film is used as separator, then thermal stability is improved, but tensile strength becomes low causing separator to be easily torn
Solution Approach 1:
The invention uses a composite structure where the polyolefin separator substrate provides high tensile strength and mechanical durability, while the inorganic coating layer on top provides thermal stability. This composite approach allows both requirements to be met simultaneously without compromising either property.
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 electrode-integrated separator provides excellent bonding durability and thermal stability while maintaining ionic conductivity, enhancing the safety and performance of lithium ion secondary batteries.
Implementation Method 1
the separator is required to have ion permeability and mechanical strength such that an electrolytic solution can pass smoothly through the separator
Implementation Method 2
an adhesive portion pattern formed on the electrode active material layer; and a porous layer that is tightly bonded to the electrode active material layer through the adhesive portion pattern
Data Source
AI summary
An electrode-integrated separator for a lithium ion secondary battery includes an electrode portion including an electrode active material layer stacked on an electrode current collector, an adhesive portion pattern formed on the electrode active material layer, and a porous layer. The porous layer is tightly bonded to the electrode active material layer through the adhesive portion pattern. The porous layer includes a polymer binder and inorganic fine particles dispersed on the polymer binder. A lithium ion secondary battery comprising the same is also provided. The electrode-integrated separator has excellent bonding durability without impairing ionic conductivity between electrodes.