Battery Separator Coating for Thin Cells With Safer High-Rate Performance
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Solution Overview
Problem
Existing secondary batteries face challenges in balancing high energy density with good rate performance, storage performance, and safety performance.
Innovation Solution
A separator comprising a substrate with a coating containing inorganic and organic particles, where the organic particles are distributed in a specific ratio and morphology to enhance bonding, reduce wrinkling, and form protective insulation layers, thereby improving safety and rate performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the energy density of secondary batteries is increased, then the battery can store more energy, but the rate performance, storage performance, or safety performance deteriorates
Solution Approach 1:
The patent applies local quality by creating a coating layer with specific spatial distribution of particles on the separator surface. The coating includes inorganic particles (such as alumina, silica) and organic particles (such as polyacrylonitrile, carboxymethyl cellulose) distributed in specific regions of the separator, providing localized functional properties that improve safety and performance without compromising energy density
Solution Approach 2:
The patent uses composite materials by combining multiple particle types in the coating layer: inorganic particles provide thermal stability and structural support, while organic particles provide bonding and protective functions. This composite structure allows the separator to simultaneously achieve high energy density through thinness and improved reliability through enhanced safety properties
2Length of stationary object
If the thickness of the separator is reduced to improve energy density, then the energy density increases, but the bonding between separator and electrode plate deteriorates and wrinkling increases
Solution Approach 1:
The patent applies parameter changes by modifying the surface properties of the separator through the coating layer. The coating particles change the surface roughness, porosity, and chemical composition parameters, enabling thin separators to achieve strong bonding with electrode plates through improved surface characteristics rather than relying on thickness
Solution Approach 2:
The patent uses segmentation by dividing the coating into distinct particle components with different functions. The inorganic particles provide structural framework while organic particles provide bonding mechanisms, creating a segmented functional structure that enhances bonding strength despite reduced separator thickness
Data Source
AI summary
A separator, comprising a substrate and a coating provided on at least one surface of the substrate are provided. In some embodiments, the coating comprises inorganic particles and organic particles, the organic particles comprise first organic particles and second organic particles both embedded in the inorganic particles and forming protrusions on the surface of the coating; the first organic particles are secondary particles, and the number of the first organic particles in the coating is denoted as A; the second organic particles are primary particles and the number of the second organic particles in the coating is denoted as B; with the separator satisfying: 0.05≤A/B<1. The present application also relates to a method for preparing the separator, as well as a secondary battery comprising the separator, a battery module, a battery pack and a device.