Separator with Inorganic Resin Layer for High-Voltage Battery
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Solution Overview
Problem
Lithium ion secondary batteries face deterioration in battery characteristics due to oxidation decomposition when the charge voltage exceeds 4.25V, leading to increased internal resistance and reduced energy density.
Innovation Solution
A separator with a resin layer containing inorganic substances is used, providing excellent oxidation resistance and heat resistance, which helps maintain battery characteristics and facilitate the manufacturing of rolled electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the charge voltage is set to 4.25V or more, then the energy density is improved, but the separator is subjected to oxidation decomposition and battery characteristics deteriorate
Solution Approach 1:
The separator is constructed as a composite material combining a polyolefin base material layer with a resin layer containing inorganic substance particles (such as alumina, silica, or titania). This composite structure provides both the mechanical integrity of the polyolefin and the oxidation resistance of the inorganic-containing resin layer, enabling the separator to withstand high charge voltages of 4.25V or more without oxidation decomposition while maintaining battery characteristics
Solution Approach 2:
The resin layer containing inorganic substances is formed specifically on one or both surfaces of the base material layer, creating a localized protective barrier at the critical interface where the separator contacts the cathode. This local modification concentrates the oxidation resistance exactly where it is needed to prevent decomposition during high-voltage charging, while the bulk polyolefin structure maintains its shutdown safety function
2Ease of manufacture
If a polyolefin microporous membrane is used, then the manufacturing is simple, but the oxidation resistance is insufficient at high charge voltages
Solution Approach 1:
The invention creates a composite separator by combining the simple polyolefin microporous membrane structure with a resin layer containing inorganic substance particles. The base polyolefin layer maintains ease of manufacture through conventional microporous membrane techniques, while the added resin layer with inorganic content (such as alumina, silica, or titania particles dispersed in a resin matrix) provides the necessary oxidation resistance for high-voltage operation
Solution Approach 2:
The separator maintains a microporous structure throughout, allowing the porous polyolefin base material to enable simple manufacturing and ion transport, while the resin layer containing inorganic substances is also formed as a microporous structure that provides oxidation resistance without blocking ion flow. The porous structure is achieved through phase separation or foam formation techniques that create interconnected voids
3Object-affected harmful factors
If the inorganic substance is added to the resin layer, then the oxidation resistance is improved, but the device complexity increases
Solution Approach 1:
The separator is divided into two functional segments: a base material layer providing mechanical strength and shutdown safety, and a surface resin layer containing inorganic substances that provides oxidation resistance. This segmentation allows each layer to be optimized for its specific function while keeping the overall structure relatively simple and manufacturable through sequential coating processes
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 separator with an inorganic substance layer enhances the durability and oxidation resistance of the battery, preventing deterioration and improving heat resistance, thus maintaining battery performance and energy density.
Implementation Method 1
the separator has excellent oxidation resistance, so that the deterioration of the battery characteristics can be suppressed
Implementation Method 2
since the inorganic substances are on the surface of the separator, the separator has good heat resistance properties
Data Source
AI summary
A separator having a structure in which a resin layer is formed at least on one principal plane of a base material layer, wherein the resin layer has an inorganic substance is provided. A non-aqueous electrolyte battery in which a cathode and an anode are arranged through the separator so as to face each other is also provided.