Composite Battery Separator With Nanofiber Ceramic Mesh Strength

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Solution Overview

Problem

Conventional lithium-ion battery separators face challenges in achieving high support strength, puncture strength, and electrolyte infiltration performance, which affects the safety and service life of lithium-ion batteries.

Innovation Solution

A composite separator is proposed, comprising a base membrane, a first nanofiber layer, and ceramic powder. The nanofiber layer is positioned on one side of the base membrane, and the ceramic powder forms a ceramic coating between the nanofiber layer and the base membrane or is added to the nanofiber layer, creating a mesh-shaped structure that enhances structural strength and prevents lithium dendrite formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a separator is made thinner and lighter to accommodate more electrode materials, then the energy density and capacity of the battery are improved, but the safety performance and mechanical strength of the separator deteriorate

Engineering Contradiction:

Improveenergy densityVSAvoidmechanical strength

Core Design Contradiction:

Quantity of substanceVSStrength

Solution Approach 1:

The patent uses a composite structure consisting of a polyolefin base membrane combined with a ceramic coating layer. This composite material approach allows the separator to maintain thin dimensions for high energy density while the ceramic layer provides enhanced mechanical strength and thermal stability, resolving the contradiction between thinness and strength.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The ceramic coating is applied locally on the surface of the base membrane, creating regions with different properties. The base membrane provides flexibility and basic separation function, while the ceramic-coated regions provide enhanced strength and heat resistance, allowing the separator to be thin overall while having localized strength enhancement where needed.

Inventive Principle:

Principle #3Local quality

2Reliability

If a ceramic coating is applied on the base membrane to improve thermal and mechanical performance, then the safety performance is improved, but the electrolyte infiltration performance and mechanical performance need further improvement

Engineering Contradiction:

Improvesafety performanceVSAvoidelectrolyte infiltration performance

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs a porous ceramic coating layer with controlled pore structure. The porous structure allows electrolyte to infiltrate and penetrate through the coating layer effectively, maintaining good ionic conductivity. At the same time, the ceramic material provides the required thermal and mechanical strength, resolving the contradiction between safety enhancement and electrolyte infiltration.

Inventive Principle:

Principle #31Porous materials

3Strength

If the separator structure is complexed with multiple layers to enhance safety, then the puncture strength is improved, but the device complexity increases

Engineering Contradiction:

Improvepuncture strengthVSAvoidseparator structure complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The separator is segmented into two functional layers: a base membrane layer for basic separation and a ceramic coating layer for enhanced protection. This segmentation allows each layer to perform its specific function optimally while keeping the overall structure relatively simple, avoiding the need for complex multi-layer configurations.

Inventive Principle:

Principle #1Segmentation

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 composite separator improves electrolyte infiltration, mechanical performance, thermal stability, and cycle stability, effectively preventing lithium dendrite puncture and enhancing the safety and service life of lithium-ion batteries.

Implementation Method 1

lithium ions are uniformly deposited on the mesh-shaped structure, thereby avoiding formation of a lithium dendrite

Methodology Applied

Scientific EffectIon deposition: Deposition (physical)

Implementation Method 2

the ceramic powder forms a first ceramic coating, positioned between the first nanofiber layer and the base membrane

Methodology Applied

Scientific EffectCoating deposition: Deposition (physical)

Implementation Method 3

a force applied to a single point on the mesh-shaped structure can be uniformly diffused from the level of a point to the level of a surface

Methodology Applied

Scientific EffectForce diffusion:

Data Source

PatentUS20250112331A1Composite separator and method for preparing same, and battery

Publication Date: 2025.04.03 SHANGHAI ENERGY NEW MATERIALS TECHNOLOGY CO LTD

AI summary

The present application proposes a composite separator, including: a base membrane, a first nanofiber layer, and a ceramic powder. The first nanofiber layer is positioned on a first side of the base membrane. The ceramic powder forms a first ceramic coating positioned between the first nanofiber layer and the base membrane, or, the ceramic powder is added to the first nanofiber layer. In addition, the present application further proposes a method for preparing the composite separator, and a battery.