Ultracapacitor Separator Pore Structure for High-Temperature Stability
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Solution Overview
Problem
Ultracapacitors are sensitive to electrical resistance and moisture, which affects their performance and commercial viability, requiring a separator that can withstand high temperatures and maintain electrical properties during the curing process.
Innovation Solution
A microporous ultracapacitor separator made from ultrahigh molecular weight polyethylene (UHMWPE) with a particulate filler, designed to have a network of interconnecting pores and a high volume percentage of pores less than 1.0 micrometers, which provides minimal resistance and maintains stability at elevated temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional separator materials are used, then manufacturing cost is reduced, but electrical resistance increases at high temperatures
Solution Approach 1:
The separator is constructed as a composite material combining polyolefin base material with specific additives and surface treatments. This composite structure enables the separator to maintain low electrical resistance at high temperatures while using cost-effective base materials, resolving the contradiction between material cost and high-temperature electrical stability
Solution Approach 2:
The invention modifies key parameters of the separator material including pore size distribution, surface energy characteristics, and chemical composition through controlled processing. These parameter changes enable the separator to maintain stable electrical resistance properties at elevated temperatures without requiring expensive exotic materials
2Reliability
If separator porosity is increased to reduce resistance, then ionic conductivity improves, but mechanical strength decreases
Solution Approach 1:
The separator utilizes a specifically designed porous structure with controlled pore size distribution and interconnectivity. The porous architecture is optimized to provide adequate ionic conductivity pathways while the pore walls are reinforced through material selection and processing to maintain necessary mechanical strength for handling and operation
Solution Approach 2:
The separator employs a composite structure where the porous matrix is combined with reinforcing elements or surface treatments. This composite approach allows the material to achieve both high ionic conductivity through the porous network and sufficient mechanical strength through the reinforced structure
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 microporous separator reduces electrical resistance and maintains dimensional stability at high temperatures, enhancing the performance and longevity of ultracapacitors by effectively removing moisture and improving production efficiency.
Implementation Method 1
Ultracapacitor separators are typically made of highly porous materials that provide minimal resistance to electrolyte ion movement and that at the same time, provide electronic insulator properties between opposing electrodes
Implementation Method 2
it is desired to have a robust ultracapacitor separator which can withstand these high temperatures during the life of the ultracapacitor and maintain both the physical and electrical properties of the separator material
Implementation Method 3
To drive off the moisture inside the ultracapacitor cell, high temperature curing is required. This process includes heating the ultracapacitor to a high temperature so that the moisture will dry out
Data Source
AI summary
A method for producing an ultracapacitor comprises the steps of: providing a negative porous electrode in contact with a negative conducting plate; providing a positive porous electrode in contact with a positive conducting plate; providing an ultracapacitor separator being a microporous material that separates the negative porous electrode from the positive porous electrode; providing an electrolytic solution that impregnates the negative porous electrode, the positive porous electrode, and the ultracapacitor separator; and curing the ultracapacitor at a temperature of at least 200° C.