Battery Separator Coating With Protrusions for Thin, Permeable Cells
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Solution Overview
Problem
Existing secondary batteries face challenges in balancing high energy density with good cycling and safety performance, as increasing energy density often compromises dynamic, electrochemical, and safety performance.
Innovation Solution
A separator is designed with a coating comprising inorganic particles and first organic particles with a primary particle morphology and specific size, forming protrusions, which enhances bonding with electrode plates and maintains ion transmission channels, thereby improving cycling and safety performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the energy density of secondary batteries is increased, then the battery capacity is improved, but the cycling performance and safety performance deteriorate
Solution Approach 1:
The separator uses a composite coating structure combining inorganic particles (alumina, silica) with organic binder particles, creating a multi-material system that simultaneously achieves high energy density through thinness and improved reliability through enhanced thermal stability and bonding characteristics
Solution Approach 2:
The coating layer is designed with non-uniform particle distribution and varying local composition, where inorganic particles provide localized thermal stability while organic binders provide localized bonding, creating different functional zones within the same coating to balance energy density and safety requirements
2Length of stationary object
If the thickness of the separator is reduced, then the energy density is improved, but the air permeability and ion transmission may deteriorate
Solution Approach 1:
The coating layer is designed as a porous structure with interconnected voids between inorganic and organic particles, allowing efficient ion transmission and air permeability even at reduced thickness, while maintaining mechanical integrity through the particle network
Solution Approach 2:
The invention transitions from a dense homogeneous coating to a three-dimensional porous particle network structure, where ion transmission occurs through vertical and lateral pathways within the particle assembly, effectively decoupling thickness from permeability performance
3Reliability
If the coating structure is optimized for bonding, then the cycling performance is improved, but the manufacturing complexity increases
Solution Approach 1:
The invention combines multiple functions (bonding, thermal stability, porosity control) into a single integrated coating layer with co-embedded inorganic and organic particles, eliminating the need for separate functional layers and simplifying the overall manufacturing process while achieving superior cycling performance
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 reduces thickness, ensures good air permeability, and improves bonding with electrode plates, leading to enhanced cycling and safety performance of secondary batteries.
Implementation Method 1
a coating formed on at least one surface of the substrate, wherein the coating comprises inorganic particles and first organic particles embedded in the inorganic particles and forming protrusions on the surface of the coating
Implementation Method 2
sufficient and non-uniformly distributed voids are formed between the inorganic particles and the organic particles, which can not only ensure the good air permeability of the separator, but also improve the bonding between the separator and the electrode plate
Data Source
AI summary
The present application relates to a separator, comprising a substrate and a coating formed on at least one surface of the substrate, wherein the coating comprises inorganic particles and first organic particles embedded in the inorganic particles and forming protrusions on the surface of the coating, and the first organic particles have a primary particle morphology and a number-average particle size of ≥2 μm. The present application also relates to a secondary battery comprising the separator, a device comprising the secondary battery and a method for preparing the separator.