• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.4
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• pp.109-116
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• 2019

The mechanical deformation of a battery separator causes internal short-circuiting of the cathode - anode, which directly affects the explosion/ignition of batteries. To increase the mechanical properties of the separator fabricated by electro-spinning, use of a thermal pressing method is inevitable. Therefore, this research aims to maximize the mechanical strength of a porous separator by finding the proper thermal press temperatures given to Electro-spun Polyacrylonitrile (PAN) nanofibers. The different thermal press temperatures $25^{\circ}C$, $50^{\circ}C$, $75^{\circ}C$, and $100^{\circ}C$ were applied to the electro-spun fiber at 30 MPa pressure for one hour. The higher the temperature, the higher the resultant tensile strength; however, a higher temperature also lowered the strain and porosity. Thus, the membrane thermal pressed at $50^{\circ}C$ showed the best mechanical properties and the second highest porosity. Using the data, $50^{\circ}C$ was judged as the best thermal pressing temperature in terms of performance.

• Polymer(Korea)
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• v.26 no.1
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• pp.45-52
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• 2002

The separator made from the blends of high density polyethylene (HDPE) and ultrahigh molecular weight polyethylene (UHMWPE) was prepared by wet processing to use as Li-ion secondary battery. We investigated effects of the blending of the polymers and the film extension on the mechanical properties of the separator. The mechanical strength of separator increased with increasing molecular weights and contents of UHMWPE, for instance about $1000 kg/\textrm{cm}^2$ with the five times extended film of 6 wt% UHMWPE. The pores of the separator were very uniform with the size of 0.1~$0.12\mu\textrm{m}$. The shut-down characteristic quickly increased at around $130^{\circ}C$ and the fusion temperature was $160^{\circ}C$, so it could be applied to the lithium ion secondary battery.

• Journal of Biosystems Engineering
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• v.5 no.1
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• pp.43-50
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• 1980

The milling plants in Korea have been generally used the paddy-separator that operated in accordance with the principle of sieving action. This type of paddy separator was considered as inefficient, especially in relation to the new high-yielding varieties which have different size characteristics within their varieties and also as compared to traditional varieties. With the installation of modern paddy separator it may be possible to increase the overall milling system efficiency and to reduce the grain loss. This study was intended to identify and define important parameters required for assessing the separation performance of a tray-type paddy separator and to determine the optimum conditions of the inclination of separator-table. The results of the study were summarized as follows : (1) Separation performance can be given by use of many parameters found from the measurement of separator outputs. such as upper-tail recovery $(\varepsilon)$, purity of upper-tail $(\gamma)$ , separation recovery of brown rice $(\alpha)$, separation recovery paddy $(\beta)$, and efficiency of separator $(\epsilon)$, Among these para-meters , $\varepsilon$, $\gamma$, $\alpha$ and $\beta$, were designated , respectively, their independent properties of the paddy separator. In addition, their modes of variation due to a varied inclination of the separation table did not indicated in the same direction . However, the efficiency of separator had an advantage to indicate the overall characteristics of the separator performance with a clear optimum inclination condition of the separator table. (2) The optimum feed rate and maximum efficiency of the separator did not occur at the identical inclination of the separator table. Thus, for its practical operation it is necessary to compromise between the qualitative and quantitative performances of the separator. (3) The optimum setting of the separator table tested in the study showed to occur at its inclination of approximately $26^\circ<$/TEX> for the front and $8^\circ<$/TEX> for lateral.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.27-32
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• 2003

Nanotechnology is the creation and utilization of materials, devices, and systems through the control of matter on the nanometer-length scale, that is, at the level of atoms, molecules, and supramolecular structures. The essence of nanotechnology is the ability to work at these levels to generate larger structures with fundamentally new molecular organization. These nanostructures, made with building blocks understood from first principles, are the smallest human-made objects, and they exhibit novel physical, chemical, and biological properties and phenomena. The aim of nanotechnology is to loam to exploit these properties and efficiently manufacture and employ the structures. Control of matter on the nanoscale already plays an important role in scientific disciplines as diverse as physics, chemistry, materials science, biology, medicine, engineering, and computer simulation. This paper describes the superprecision nano separator to productive particle size of nano powder. this separator system is very important in the industrial area for other high technology parts.

• Polymer(Korea)
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• v.37 no.1
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• pp.22-27
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• 2013

In this study, we prepared separators with improved thermal stability by coating microporous polyethylene (PE) film for lithium secondary battery using poly(meta-phenylene isophthalamide) (Nomex). The mechanical and thermal properties of prepared separators were evaluated by thermal stability test and TMA as a function of the Nomex concentration and coating parameters. The corresponding coated PE separator showed better thermal and mechanical properties than the original PE separator. Electrochemical properties were also assessed by ionic conductivity, cyclic voltammetry and charge/discharge cycle.

• Journal of the Korean Electrochemical Society
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• v.20 no.3
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• pp.49-54
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• 2017

We develop a ceramic composite separator prepared by coating $ZrO_2$ nanoparticles with a poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) copolymer on a polyvinyl alcohol (PVA) mechanical support prepared by electrospinning technique to improve thermal properties. The gurley number of the ceramic composite separator shows much lower value than that of a PE separator even though it possesses the polymeric coating layer with ceramic nanoparticles. In addition, the proposed sample shows higher electrolyte uptake than PE separator, leading to enhancing the ionic conductivity of the proposed sample and, by extension, the rate discharge properties of lithium ion batteries. Thermal stability of the ceramic composite separator is dramatically improved without any degradation in electrochemical performance compared to the performance of conventional PE separators.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.3
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• pp.78-83
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• 2010

This paper presents the feasibility of incorporating ultrafine particles collected in the separator bag filter (separator bag filter cement, SBFC) during the cement manufacturing process as an substitution material for cement. SBFC does not require additional processes needed in the existing processes to manufacture high early strength cement such as modifying mineral components and adjusting the firing temperature. Moreover, it can also solve the issue of efficiency decrease resulted from the increase of the grinding time applied in the existing process of manufacturing microcement. Therefore, this research has examined the characteristics of SBFC and fresh properties and mechanical properties after making paste and mortar using SBFC in order to use SBFC as a material to gain early strength of concrete. For results, analyzing the chemical composition and physical properties of SBFC, its blaine value was $6,953cm^3/g$, about double than that of OPC, but its chemical composition showed no significant difference. According to the result of the paste and mortar examination, the paste and mortar mixed with SBFC showed a lower flowability, earlier setting time, and higher compressive strength than that with OPC. The result of microstructure analysis of paste, the paste mixed with SBFC indicated about 9% lower internal porosity at an early age than that of OPC. The compressive strength and flexural strength of mortar were higher in the order of SBFC ratio of 100, 50 and 0% SBFC.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.247-250
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• 2009

This study considers the feasibility of using the low cost assembled separator. The graphite plate has been widely used as the separator in the field of PEMFCs(Polymer electrolyte membrane fuel cell) industry because of its excellent material properties such as good corrosion resistance, good electrical conductance and so on. However, there are some problems for the commercialization due to its poor cost effectiveness for the large volume manufacturing and lack of mechanical strength. From this respect, this study has focused on the manufacturing technology in order to reduce the price for the commercialization of separator. This study also shows that the assembled separator of the suggested structure, which is composed of grafoil and PC(PolyCarbonate) materials, could be manufactured at low cost enough for the mass production. The flow fields produced by cutting foils and the base plates of the separators were simply made by mechanical work.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1178-1181
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• 2003

Nanotechnology is the creation and utilization of materials, devices, and systems through the control of matter on the nanometer-length scale, that is, at the level of atoms, molecules, and supramolecular structures. The essence of nanotechnology is the ability to work at these levels to generate larger structures with fundamentally new molecular organization. These nanostructures, made with building blocks understood from first principles, are the smallest human-made objects, and they exhibit novel physical, chemical, and biological properties and phenomena. The aim of nanotechnology is to learn to exploit these properties and efficiently manufacture and employ the structures. Control of matter on the nanoscale already plays an important role in scientific disciplines as diverse as physics, chemistry, materials science, biology, medicine, engineering, and computer simulation. This paper describes the superprecision nano separator to productive particle size of nano powder. this separator system is very important in the industrial area for other high technology parts.

• Membrane Journal
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• v.7 no.3
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• pp.123-130
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• 1997

The characteristics of microporous separator for lithium ion secondary battery was introduced. Microporous separator is a key component of a lithium ion secondary battery because its basic properties were related with the performance and safety of the battery. Up to now, stretched microporous polyolefins such as polyethylene(PE) separator were mainly applied. It is still required to enhance wettability and shut-down property. For this purpose, the application of fluorovinylic polymers and surface modification of conventional polyolefinic microporous membrans we being continuously tried.