• Title/Summary/Keyword: Rolling electrode

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The Effect of Rolling on the Charge-Discharge Characteristic of Metal Hydride Electrode for Ni-MH Secondary Battery (압연이 Ni-MH 2차전지용 금속수소화물 전극의 충·방전 특성에 미치는 영향)

  • Park, Won;Chang, Sang-Min;Choi, Seung-Jun;Noh, Hak;Choi, Jeon;Park, Choong-Nyeon
    • Journal of Hydrogen and New Energy
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    • v.7 no.2
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    • pp.165-171
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    • 1996
  • The effect of rolling on the charge-discharge property was studied for metal hydride negative electrode. $(LM)Ni_{3.6}Al_{0.4}Co_{0.7}Mn_{0.3}$(pleateau pressure : below 1 atm at room temperature, volume expansion : 9%, entalpy : $8.7kcal/molH_2$) alloy was prepared by arc melting, and then it was coated with various copper weight percent. The copper coated alloys were then rolled with the different reduction ratio. From the results, it was found that the maximum discharge capacity increased with increasing reduction ratio, and 15wt% copper coated sample shows the highest discharge capacity, 324mAh/g, after rolling with 30% reduction ratio. In view of cycle life for the negative electrode, the 15wt% copper coated electrode which was rolled with 13% reduction ratio showed the longest cycle life compared with other electrodes.

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A Study on the Development of Insulated Electrode Tip for Spot Welding to Reduce Indentation (점용접 시 압흔 깊이 감소를 위한 절연팁 개발에 관한 연구)

  • 서승일;장상길
    • Journal of Welding and Joining
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    • v.21 no.1
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    • pp.42-47
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    • 2003
  • Stainless rolling stocks are usually fabricated by spot welding process without painting. Indentation on the surface of the car body after spot welding injures the beauty of the stainless rolling stocks. In this study, insulated electrode tips to reduce the indentation are developed and applied to the actual spot welding works. The developed tips are composed of head, neck, hole for cooling water, body and resistance material. They provide large surface contact area with the base materials during spot welding and enhance the current density by necking. Experimental results using the developed tips show that small indentation and sufficient tensile shear strength is produced due to large contact area and enhanced current density.

Analysis of a Hot Rolling Roller and Spring-back of Electrode Materials for Secondary Batteries (이차전지 전극제조용 열간압연롤러와 전극재료의 열 변형 및 스프링백 해석)

  • Kim, Kyung-Sik;Kim, Cheol
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.538-543
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    • 2008
  • A roller with a shaft and hot oil paths for pressing electrodes of polymer batteries were modeled and analyzed by FEM. There are many hot oil tubes in the roller and shaft, through which $72^{\circ}C$ hot oil flows for heating the surface of a roller and shaft. Thermal deformations and temperatures distributions of the roller and shaft were calculated and a convection boundary condition on surfaces was used. The influence of existence of a groove in the shaft on the flatness of a roller surface caused by thermal deformation was investigated. In addition, the amount of spring-back of electrodes under vacuum pressure and heating was calculated after the hot rolling process. It was shown from this study that the groove in one shaft had a favorable effect on the surface flatness.

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Development of electrode tips for spot welding to reduce indentation of car body surface of stainless rolling stocks (스텐레스 철도차량 외판 압흔 깊이 감소를 위한 스폿용접용 전극팁 개발)

  • 서승일
    • Proceedings of the KSR Conference
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    • 2002.05a
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    • pp.386-391
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    • 2002
  • Stainless rolling stocks are usually fabricated by spot welding process without painting. Indentation on the surface of the car body after spot welding injures the beauty of the stainless rolling stocks. In this study, electrode tips to reduce the indentation are developed and applied to the actual spot welding works. The developed tips are composed of head, nut hole far cooling water, body and resistance material. They provide large surface contact area with the base materials during spot welding and enhance the current density by necking. Experimental results using the developed tips show that small indentation and sufficient tensile shear strength is produced due to large contact area and enhanced current density.

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Electrode fabrication and Performance of Single Cell with an area of $2000\;cm^2$ in PAFC ($2000\;cm^2$ 대면적 인산형 연료전지 전극 제조 및 단위전지 성능 특성)

  • Song, Rak-Hyun;Shin, Dong-Ryul;Kim, Chang-Soo;Lee, Byung-Rok;Choi, Soo-Hyun
    • Proceedings of the KIEE Conference
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    • 1997.07d
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    • pp.1308-1310
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    • 1997
  • Several methods for electrode fabrication of phosphoric acid fuel cell(PAFC) have been studied. The conventional methods that include a coating method and a rolling method, have disadvantages of a very complicated drying process and a hot pressing process for making a large electrode. In this study, to solve these problems, the mixing method of coating and rolling processes has been developed. In the mixing method, the electrode was coated on the electrode support and, after drying the coated layer, was rolled at room temperature and then sintered at $350^{\circ}C$. The single cell performances of the electrodes fabricated by several methods were examined and the mixing method appeared a good cell performance of 0.65 V, $260\;mA/cm^2$. Also the single cell with an area of $2000\;cm^2$ was manufactured and its performance attained 0.593 V, 300 A.

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A Study on the Sheet Separation Reduction of Stainless Steel using Hollow Spot Electrode Tip for Resistance Spot Welding (가공 전극 팁을 이용한 스테인레스 저항 용접 외판 변형 저감)

  • Huh, Dong-Woon;Rhee, Se-Hun
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.20 no.6
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    • pp.679-684
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    • 2011
  • Recently, STS 301L joints of side panels to frames for stainless steel rolling stock have been made out by using existing welding methods including Resistance Spot Welding, Laser Welding and Arc Welding. Most of the processes were jointed by spot welding because it is faster at welding and comparatively less expensive for investment in welding facilities than other methods. During spot welding, however, indentation of the metal surface was made due to pressure and melting property of welding. Moreover, since the melting metal was forced to periphery of the plate as indentation was made, sheet separation, which cracked apart between jointed sheets, was carried out. A slight deformation which resulted from sheet separation deteriorated the emotional quality of railway vehicles. This paper suggests that by processing conventional spot electrode tip appropriately, melting metal is able to push up around the processed part (Hollow Spot Electrode Tip) and prevent from being dislodged from first place to periphery. Consequently, sheet separation is remarkably decreased. Also, the emotional quality of appearance of stainless steel rolling stock is enhanced considerably.

Electrochemical Characteristics of EDLC Fabricated by Different Preparation Processes of Activated Carbon Electrode (활성탄소 전극의 제조공정에 따른 EDLC의 전기화학적 특성)

  • Yang Chun-Mo;Kim H.J.;Cho W.I.;Cho B.W.;Yun K.S.;Rim Byung-O
    • Journal of the Korean Electrochemical Society
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    • v.4 no.3
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    • pp.98-103
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    • 2001
  • The electrochemical characteristics and specific capacitance were investigated by preparation processes (dip coating method, doctor blade coating method and paste rolling method) of activated carbon electrode for an EDLC(electric double layer capacitor). The EDLC using $LiPF_6$ salts and PC-DEC solvents showed good specific capacitance, 130F/g and small IR-drop at linear time-voltage curve. 0.11V, Cyclic voltammetry analysis using the activated carbon electrode prepared by dip coating method was shown closer to ideal EDLC characterization.

Improvement of the Catalytic Properties of Porous Nickel Hydrogen Electrodes for Alkaline Fuel Cell (알칼리형 연료전지용 다공성 니켈수소극의 촉매특성개선)

  • Lee, Hong-Ki;Lee, Ju-Seong
    • Applied Chemistry for Engineering
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    • v.3 no.2
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    • pp.230-239
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    • 1992
  • Nickel was used as a catalyst for the hydrogen electrode in alkaline fuel cell. The optimum electrolyte concentration and recommendable operating temperature identified from polarization curves were 6N KOH and $80^{\circ}C$, respectively. Comparing the conductivity, apparent porosity and current density at porous hydrogen electrode manufactured with various PTFE additions, the proper content of PTFE was 10wt%. Chemisorption was carried out to define the appropriate surface area. The electrode produced with 10wt% of PTFE and sintered at $340^{\circ}C$ showed more than $200mA/cm^2$ of current density. The morphology of electrode surface was investigated with SEM. Cold pressing, hot pressing, rolling and calendering methods were carried out for manufacturing the electrode, and electrochemical characteristics for each method was studied.

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Development of CCFL with Nb/Ni Gad Electrode for high efficiency (Nb/Ni Clad 전극을 이용한 고효율 CCFL 개발)

  • Park, Ki-Duck;Yang, Seong-Su;Park, Doo-Sung;Kim, Seo-Yoon;Lim, Young-Jin
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.07a
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    • pp.441-443
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    • 2005
  • According as CCFL(Cold Cathode Fluorescent lamp) of light source in Backlight unit for Note PC (Personal computer) is presently needed to low power consumption and long life time, the development focus of CCFL is going on the discharge gas, phosphor and electrode material. First of all, discharge voltage characteristic of CCFL is closely connected with electrode material For low discharge voltage, the characteristic of electrode material is needed to low work function, low sputtering ratio and superior manufacturing property. We developed new CCFL with Nb/Ni Clad electrode superior to conventional CCFL. Because Nb/Ni Clad electrode with Ni material and Nb material, the electrical characteristic is superior to other electrode materials. The electrode of Nb/Ni Clad is composed that Ni of outside material has superior manufacturing property and Nb of inside material has low work function. Nb/Ni Clad of new electrode material is made by process of Rolling mill at high pressure and heat treatment. We compared electrical characteristic of Nb/Ni clad electrode with conventional Mo electrode by measurement. Mo electrode and Nb/Ni Clad electrode of cup type with diameter 1.1 mm and length 3.0mm are used to this experiment. Material content of Mo electrode is Mo 100%. But, Nb/Ni Clad electrode is composed by content of Nb 40% and Ni 60%. The result of comparison measurement between new CCFL with Nb/Ni Clad electrode and conventional CCFL was appeared that CCFL with Nb/Ni Clad electrode had superior characteristic than conventional CCFL. As a result of experiment, we completed Note PC with low power consumption and long life time by application of new CCFL with Nb/Ni Clad electrode.

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Shapes and Thermomechanical Analyses of a Hot Roll for Manufacturing Electrodes of Polymer Batteries (폴리머 배터리 전극제조용 압연 고온롤 표면의 형상 및 유한요소 열변형 해석)

  • Kim, Cheol;Jang, Dong-Sue;Yu, Seon-Jun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.31 no.8
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    • pp.847-854
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    • 2007
  • The battery electrode of a mobile phone is made of layered polymer coated on aluminum foils and the hot rolling process is applied to increase the density per volume of an electrode for a high capacity battery. The flatness of batteries surfaces should be less than $2{\mu}m$. To satisfy the required flatness, the deformation of roll surface due to bending and heating of the roll should be minimized. Complicated hot oil paths of $100^{\circ}C$ inside the roll are required for heating the polymer layers. FEA was used to calculate thermal deformations and temperatures distributions of the roller. Based on FEA, a modified surface curvature called a crown roll was suggested and this gave the area of 30% improved flatness compared with a flat roll. The flat roll satisfied the flatness of $2{\mu}m$ in the length of 340 mm and the crown roll resulted in the longer length of 460 mm. Experiments to measure the temperature distribution and thermal strain were performed and compared with FEA. There were only 6% difference between two results.