TFE-PPVE Copolymer for Battery Holder Insulation and Swelling Resistance

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Solution Overview

Problem

Existing materials for current collector holders in batteries lack sufficient insulating properties, electrolytic solution low permeability, crack resistance, and resistance to swelling, which affects the reliability and design flexibility of batteries.

Innovation Solution

A copolymer containing a tetrafluoroethylene unit and perfluoro(propyl vinyl ether) unit with specific content ratios and melt flow rates, providing excellent water vapor and air low permeability, chemical solution resistance, and high-temperature rigidity, is used to create a formed article with improved properties for current collector holders.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing materials are used for current collector holders, then manufacturing is simple, but insulating properties and resistance to electrolytic solution are insufficient

Engineering Contradiction:
Improveinsulating properties and resistance to electrolytic solutionVSAvoidmaterial availability and processing simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the chemical composition parameters of the fluororesin by controlling the copolymerization ratio of TFE and PPVE monomers, and by controlling the melt flow rate within a specific range (35-60 g/10min), to achieve both improved reliability and manufacturability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite fluororesin system comprising TFE-PPVE copolymer as the base material, optionally combined with other fluororesins or additives, to achieve the required insulating properties and chemical resistance while maintaining processability

Inventive Principle:
Principle #40Composite materials

2Reliability

If fluororesin composition is optimized for chemical resistance, then reliability improves, but moldability and surface smoothness deteriorate

Engineering Contradiction:
Improvechemical solution resistanceVSAvoidsurface smoothness and moldability
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent optimizes the melt flow rate parameter within the specific range of 35-60 g/10min to balance chemical resistance and moldability, and controls the PPVE content (4.8-5.7% by mass) to achieve both chemical solution resistance and surface smoothness

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies different functional requirements to different aspects of the material: high chemical resistance is achieved through the fluororesin composition, while good surface smoothness is achieved through optimized melt flow characteristics during the molding process

Inventive Principle:
Principle #3Local quality

3Productivity

If extrusion forming is used for coating, then productivity is high, but coating uniformity and defect reduction are problematic

Engineering Contradiction:
Improvecoating speed and efficiencyVSAvoidcoating thickness uniformity and defect rate
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent changes the rheological parameters of the fluororesin by controlling the melt flow rate (35-60 g/10min), which improves the coating material's flow characteristics and enables uniform coating formation at high extrusion speeds with minimal defects

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS20230383031A1Copolymer, molded body, injection molded body, and coated electrical wire
Publication Date: 2023.11.30 DAIKIN INDUSTRIES LTD

AI summary

There is provided a copolymer containing tetrafluoroethylene unit and perfluoro(propyl vinyl ether) unit, wherein the copolymer has a content of perfluoro(propyl vinyl ether) unit of 4.8 to 5.7% by mass with respect to the whole of the monomer units, a melt flow rate at 372° C. of 33.0 to 39.0 g/10 min, and the number of functional groups of 50 or less per 106 main-chain carbon atoms.