Water-Based Polyimide Powder Separator Manufacturing

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Solution Overview

Problem

Conventional polyimide separators for lithium-ion batteries are environmentally unfriendly and costly due to the use of organic solvents, high voltage, and high temperature in their manufacturing process, which also compromises their mechanical strength and stability.

Innovation Solution

A method for manufacturing a polyimide-powder composite separator using a dianhydride and diamine reaction in water, followed by mixing with a binder to create a polyimide-binder solution, which is then coated onto a separator, eliminating the need for organic solvents and high-temperature processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional polyimide separators are manufactured using organic solvents and high temperature processes, then heat resistance and chemical resistance are improved, but environmental friendliness deteriorates and manufacturing cost increases

Engineering Contradiction:

Improveheat resistanceVSAvoidenvironmental friendliness

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the fundamental parameter of the dispersion medium from organic solvent to water, and changes the processing temperature from high temperature to room temperature or mild heating. This allows the manufacturing of polyimide separators without compromising heat resistance while significantly improving environmental friendliness and reducing manufacturing costs

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses water as a disposable, environmentally friendly dispersion medium instead of expensive and harmful organic solvents. The water-based system can be easily discarded without special treatment, reducing both cost and environmental impact while maintaining the required separator performance

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Reliability

Engineering Contradiction:

Improveheat resistanceVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the processing temperature parameter from high temperature to room temperature or mild heating conditions, and changes the solvent parameter from expensive organic solvent to cheap water. This dramatically reduces manufacturing cost while maintaining heat resistance through the inherent properties of the polyimide structure formed in the water-based system

Inventive Principle:

Principle #35Parameter changes

3Productivity

If separator thickness is diminished to increase capacity, then energy density is improved, but mechanical strength deteriorates

Engineering Contradiction:

Improveenergy densityVSAvoidmechanical strength

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

The patent creates a composite structure by coating the porous separator substrate with a polyimide layer formed from water-based polyimide powder. This composite structure provides enhanced mechanical strength and thermal stability to the thin separator, enabling reduced thickness for higher energy density while maintaining sufficient mechanical strength

Inventive Principle:

Principle #40Composite materials

4Reliability

If inorganic particles and polymer binder are coated on separator to suppress shrinkage and block dendrites, then safety is improved, but ion mobility resistance increases

Engineering Contradiction:

ImprovesafetyVSAvoidion mobility resistance

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the problematic polymer binder component from the coating system, using only water-based polyimide powder. This removes the source of increased ion mobility resistance while maintaining the safety functions of shrinkage suppression and dendrite blocking through the polyimide coating itself

Inventive Principle:

Principle #2Taking out (Extraction)

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 method produces a separator with improved mechanical strength, reduced thermal shrinkage, and enhanced electrolyte absorption, while being environmentally friendly and cost-effective, thus addressing the limitations of conventional polyimide separators.

Implementation Method 1

preparing a polyimide-powder from a dianhydride and a diamine using water as a dispersion medium

Methodology Applied

Scientific EffectPolymerization: Chemical Bonding

Implementation Method 2

coating a separator with the solution

Methodology Applied

Scientific EffectCoating: Coatings

Implementation Method 3

provide a pathway for ionic conduction

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 4

block the current as a part of the separator melts and the pores are closed when the temperature rises

Methodology Applied

Scientific EffectMelting: Melting

Data Source

PatentUS20230178854A1Water based polyimide-powder coating composition and method for manufacturing composite separator for lithium secondary battery using same

Publication Date: 2023.06.08 XERABRID CO LTD

AI summary

The present invention relates to a method for manufacturing a polyimide-powder composite separator using water and a polyimide-powder composite separator manufactured by the method, and is environmentally friendly since an organic solvent is not used in the overall process of manufacturing the composite separator and has advantageous effects in terms of time, cost, and manufacturing process since a high temperature/high pressure environment is not required.