Coated Nonwoven Battery Separator for Puncture and Melt Integrity

Solution Overview

Problem

Current battery separators for lithium batteries lack improved puncture strength, reduced splittiness, enhanced high temperature melt integrity, and increased tensile strength, which are critical for better performance and safety.

Innovation Solution

A battery separator is developed by laminating a microporous membrane with a coated nonwoven, where the coating contains a polymer and optional filler or particles, and the lamination process involves unwinding, laminating, and coating the nonwoven before or after lamination, using techniques like calendering to create an interfacial bond.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a microporous membrane is used as a battery separator, then ion flow pathway is provided, but puncture strength and tensile strength are insufficient

Engineering Contradiction:

Improvepuncture strengthVSAvoidseparator performance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent applies composite materials by combining a microporous membrane with a nonwoven layer to create a laminated separator structure. This composite construction provides both the ion flow pathway functionality of the microporous membrane and the mechanical strength of the nonwoven layer, simultaneously addressing puncture strength and tensile strength requirements while maintaining separator reliability.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent merges two distinct components - a microporous membrane and a nonwoven layer - into a single laminated separator structure. This merging allows the separator to fulfill multiple functions: providing ion flow pathways through the microporous membrane while gaining enhanced mechanical properties from the nonwoven layer, thereby improving overall separator performance.

Inventive Principle:

Principle #5Merging (Combining)

2Strength

If a microporous membrane is used as a battery separator, then ion flow pathway is provided, but tensile strength is insufficient

Engineering Contradiction:

Improvetensile strengthVSAvoidseparator performance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent applies composite materials by combining a microporous membrane with a nonwoven layer to create a laminated separator structure. This composite construction provides both the ion flow pathway functionality of the microporous membrane and the mechanical strength of the nonwoven layer, simultaneously addressing puncture strength and tensile strength requirements while maintaining separator reliability.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent merges two distinct components - a microporous membrane and a nonwoven layer - into a single laminated separator structure. This merging allows the separator to fulfill multiple functions: providing ion flow pathways through the microporous membrane while gaining enhanced mechanical properties from the nonwoven layer, thereby improving overall separator performance.

Inventive Principle:

Principle #5Merging (Combining)

3Temperature

If a microporous membrane is used as a battery separator, then shutdown function is provided, but high temperature melt integrity is insufficient

Engineering Contradiction:

Improvehigh temperature melt integrityVSAvoidseparator safety

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The patent applies composite materials by combining a microporous membrane with a nonwoven layer to create a laminated separator structure. The nonwoven layer provides high temperature melt integrity while the microporous membrane maintains the shutdown function, achieving both thermal stability and safety requirements through material composition.

Inventive Principle:

Principle #40Composite materials

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 solution enhances puncture strength, reduces splittiness, improves high temperature melt integrity, and increases tensile strength in both machine and cross-machine directions, thereby improving the safety and performance of lithium batteries.

Implementation Method 1

The separator is typically microporous and provides a pathway for ions in the electrolyte to flow from one electrode to the other during the charge and discharge cycles of a battery

Methodology Applied

Scientific EffectIon transport through microporous structure: Porosity

Implementation Method 2

laminating the nonwoven and microporous membrane, and coating the nonwoven before or after lamination

Methodology Applied

Scientific EffectThermal lamination bonding: Lamination

Data Source

PatentUS20240034023A1Battery separators and related methods

Publication Date: 2024.02.01 CELGARD LLC

AI summary

Battery separators and methods are disclosed. The battery separator may be used in a lithium battery. The separator may include a microporous membrane laminated to a coated nonwoven. The coating may contain a polymer and optionally, a filler or particles. The methods may include the steps of: unwinding the microporous membrane and the nonwoven, laminating the nonwoven and microporous membrane, and coating the nonwoven before or after lamination.