• Title/Summary/Keyword: Micro-batteries

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Carbon-free Polymer Air Electrode based on Highly Conductive PEDOT Micro-Particles for Li-O2 Batteries

  • Yoon, Seon Hye;Kim, Jin Young;Park, Yong Joon
    • Journal of Electrochemical Science and Technology
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    • v.9 no.3
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    • pp.220-228
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    • 2018
  • This study introduced a carbon-free electrode for $Li-O_2$ cells with the aim of suppressing the side reactions activated by carbon material. Micro-particles of poly(3,4-ethylenedioxythiophene) (PEDOT), a conducting polymer, were used as the base material for the air electrode of $Li-O_2$cells. The PEDOT micro-particles were treated with $H_2SO_4$ to improve their electronic conductivity, and LiBr and CsBr were used as the redox mediators to facilitate the dissociation of there action products in the electrode and reduce the over-potential of the $Li-O_2$ cells. The capacity of the electrode employing PEDOT micro-particles was significantly enhanced via $H_2SO_4$ treatment, which is attributed to the increased electronic conductivity. The considerable capacity enhancement and relatively low over-potential of the electrode employing $H_2SO_4$-treated PEDOT micro-particles indicate that the treated PEDOT micro-particles can act as reaction sites and provide storage space for the reaction products. The cyclic performance of the electrode employing $H_2SO_4$-treated PEDOT micro-particles was superior to that of a carbon electrode. The results of the Fourier-transform infrared spectroscopic analysis showed that the accumulation of residual reaction products during cycling was significantly reduced by introducing the carbon-free electrode based on $H_2SO_4$-treated PEDOT micro-particles, compared with that of the carbon electrode. The cycle life was improved owing to the effect of the redox mediators. The refore, the use of the carbon -free electrode combined with redox mediators could realize excellent cyclic performance and low over-potential simultaneously.

Measurement of Micro Gas Turbine Power Pack Performance for Electric Vehicle Range Extenders Under Various Electrical Loads and Gear Ratios (전기자동차 레인지익스텐더를 위한 초소형 가스터빈 파워팩의 전기 부하 및 동력전달 기어비에 따른 성능 실험)

  • Sim, Kyuho;Park, Jisu
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.39 no.4
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    • pp.371-378
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    • 2015
  • Range extenders, which are power generation systems driven by small engines, extend the driving distance and time of electric vehicles (EVs) through continuous charging of batteries. The currently used range extenders with gasoline engines pose limitations with regard to the realization of high-power compact systems, owing to their complex structure and low energy density. In contrast, micro gas turbine (MGT) range extenders (MGT power packs) possess high power and low weight, and can therefore be significantly reduced in size despite increase in speed. In this study, an MGT power pack for the range extenders of EVs was developed using a turbo-prop micro turbine, an alternator for passenger vehicles and electric batteries. The operating characteristics of the MGT power pack were measured through a series of experiments conducted under electrical no-load and load conditions. Their power generation performance and efficiency were measured under various electrical loads and power transmission gear ratios. From the results, electrical load was found to have no influence on power generation performance. The maximum electrical power output was 0.8 kW at a core turbine speed of 150 krpm, and the application of 3:1 reduction gear to the turbine output shaft increased the power to 1.5 kW by 88%. This implies that the test results demonstrated stable power generation performance of the MGT power pack regardless of vehicle load changes, thus revealing its feasibility for use with the range extenders of EVs.

Development of Micro-Tubular Perovskite Cathode Catalyst with Bi-Functionality on ORR/OER for Metal-Air Battery Applications

  • Jeon, Yukwon;Kwon, Ohchan;Ji, Yunseong;Jeon, Ok Sung;Lee, Chanmin;Shul, Yong-Gun
    • Korean Chemical Engineering Research
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    • v.57 no.3
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    • pp.425-431
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    • 2019
  • As rechargeable metal-air batteries will be ideal energy storage devices in the future, an active cathode electrocatalyst is required with bi-functionality on both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) during discharge and charge, respectively. Here, a class of perovskite cathode catalyst with a micro-tubular structure has been developed by controlling bi-functionality from different Ru and Ni dopant ratios. A micro-tubular structure is achieved by the activated carbon fiber (ACF) templating method, which provides uniform size and shape. At the perovskite formula of $LaCrO_3$, the dual dopant system is successfully synthesized with a perfect incorporation into the single perovskite structure. The chemical oxidation states for each Ni and Ru also confirm the partial substitution to B-site of Cr without any changes in the major perovskite structure. From the electrochemical measurements, the micro-tubular feature reveals much more efficient catalytic activity on ORR and OER, comparing to the grain catalyst with same perovskite composition. By changing the Ru and Ni ratio, the $LaCr_{0.8}Ru_{0.1}Ni_{0.1}O_3$ micro-tubular catalyst exhibits great bi-functionality, especially on ORR, with low metal loading, which is comparable to the commercial catalyst of Pt and Ir. This advanced catalytic property on the micro-tubular structure and Ru/Ni synergy effect at the perovskite material may provide a new direction for the next-generation cathode catalyst in metal-air battery system.

Performance characteristics of AGM lead acid battery with the content of positive plate incorporating nano-size additive material (나노 사이즈 입자가 포함된 양극 활물질 함량에 따른 차량용 AGM 연축전지 성능 특성)

  • Lim, Tae Seop;Kim, Sung Jun;Kim, Sang Dong;Yang, Seung Cheol;Jung, Yeon Gil
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.30 no.4
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    • pp.123-130
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    • 2020
  • Nano seed incorporated in micro-sized 4BS (Tetrabasic lead Sulfate) seed was applied to the positive electrode active material and compared with Nano 4BS seed (NS). The dispersion of NS decreased due to the aggregation phenomenon, while the nano seed incorporated in micro-sized 4BS seed (INS) could confirm excellent dispersion. As the content of INS increased, the particle size of the active material became small and constant, which was confirmed through SEM and particle size analysis. The specific surface area for the reaction was increased and the high-rate discharge and lifetime characteristics were improved. In order to confirm the variation in particle size distribution in the plate manufacturing process, internal resistance and voltage were measured for 200 AGM lead-acid batteries, and it was confirmed that batteries quality variation decreased.

A Study on the Decision of Appropriate Subsidy Levels for Energy Storage Systems Considering Load Leveling in Smart Place (부하평준화 기능을 고려한 주택용 ESS의 적정 지원금 산정에 관한 연구)

  • Kim, Jung-Hoon;Hwang, Sung-Wook;Lee, Hak-Ju
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.2
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    • pp.211-216
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    • 2014
  • Construction of power plants and T&D facilities is so difficult because of the civil complaints and the additional cost according to the concerning field conditions. Therefore, various researches and methods have been considered to get solutions in the demand side and energy storage systems have been in the spotlight because of the various functions such as peak shaving, load shifting, and power system stabilizing, and so on. Residential small size batteries are considered in this paper and the economic analysis is carried out to evaluate the reasonable subsidy levels for the deployment of energy storage systems. Various economic parties are considered to find reasonable subsidy level comparing each other, which parties consist of utilities, participants and non-participants in general. The evaluation is based on California Standard Practice Test and the results are able to be used as subsidy guidelines.

Design of a 500W Class Micro Turbine Generator System as a Next Generation Military Power Source (차세대 군용전원용 500W급 마이크로 터빈 발전기 시스템 설계)

  • Choi, Sang-Kyu;Choi, Bum-Suk;Han, Yong-Shik;Woo, Byung-Chul;Song, In-Hyuck;Min, Seong-Ki;Lim, Jin-Sik
    • Journal of the Korea Institute of Military Science and Technology
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    • v.14 no.6
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    • pp.1192-1197
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    • 2011
  • Recent developments of small-size unmanned or manned mobile systems such as autonomous robots, exoskeleton or armored suits, micro air vehicles, and unmanned armored vehicles require long-lasting independent power sources of high energy and power density to support the systems' operation for up to 72 hours in the fields. Chemical batteries such as Ni-MH, Li-Ion, the current primary power sources for mobile devices, however, are not capable of providing enough power and energy density for the next generation high power mobile machines. For this reason, KIMM along with KERI and KIMS has been carrying out a 500W MTG development project under the DAPA's "Next generation military power source R&D program" since 2009. In this paper, a design process for a 500W MTG system currently being developed at KIMM is briefly described and the technical issues related to its development are addressed.

Fabrication and Electrochemical Characterization of All Solid State Thin Film Micro-Battery by in-situ sputtering (In-situ 스퍼터링을 이용한 마이크로 박막 전지의 제작 및 전지 특성 평가)

  • 전은정;신영화;남상철;조원일;손봉희;윤영수
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1999.11a
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    • pp.159-162
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    • 1999
  • All solid state thin film micro-batteries consisting of lithium metal anode, an amorphous LiPON electrolyte and cathode of vanadium oxide have been fabricated and characterized, which were fabricated with cell structure of Li/LiPON/V$_2$O$\sub$5/Pt. The vanadium oxide thin films were formed by d.c. reactive sputtering on Pt current collector. After deposition of vanadium oxide films, in-situ growths of lithium phosphorus oxynitride film were conducted by r.f. sputtering of Li$_3$PO$_4$ target in mixture gas of N$_2$ and O$_2$. The pure metal lithium film was deposited by thermal evaporation on thin film LiPON electrolyte. The cell capacity was about 45${\mu}$Ah/$\textrm{cm}^2$ $\mu\textrm{m}$ after 200 cycle. No appreciable degradation of the cell capacity could be observed after 50 cycles .

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Design of Fuse Elements of Current Sensing Type Protection Device for Portable Secondary Battery Protection System (휴대용 이차전지 보호 시스템용 전류 감지 동작형 보호소자의 퓨즈 가용체 설계)

  • Kang, Chang-Yong;Kim, Eun-Min
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.67 no.12
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    • pp.1619-1625
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    • 2018
  • Portable electronic devices secondary batteries can cause fire and explosion due to micro-current change in addition to the situation of short-circuit inrush current, safety can not be secured with a general operation limited current fuse. Therefore, in secondary battery, it is necessary for the protector to satisfy both the limit current type operation in the open-short-circuit inrush current and the current detection operation characteristic in the micro current change situation and for this operation, a fuse for the current detection type secondary battery protection circuit can be applied. The purpose of this study is to design a protection device that operates stably in the hazardous situation of small capacity secondary battery for portable electronic devices through the design of low melting fuse elements alloy of sensing type fuse and secures stability in abnormal current state. As a result of the experiment, I-T and V-T operation characteristics are satisfied in a the design of the alloy of the current sensing type self-contained low melting point fuse and the resistance of the heating resistor. It is confirmed that it can prevent accidents of short circuit over-current and micro current change of secondary battery.

Nickel Phosphide Electroless Coating on Cellulose Paper for Lithium Battery Anode

  • Kang, Hyeong-Ku;Shin, Heon-Cheol
    • Journal of Electrochemical Science and Technology
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    • v.11 no.2
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    • pp.155-164
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    • 2020
  • Here we report our preliminary results about nickel phosphide (Ni-P) electroless coating on the surface of cellulose paper (CP) and its feasibility as the anode for lithium (Li) batteries. In particular, CP can act as a flexible skeleton to maintain the mechanical structure, and the Ni-P film can play the roles of both the anode substrate and the active material in Li batteries. Ni-P films with different P contents were plated uniformly and compactly on the microfiber strands of CP. When they were tested as the anode for Li battery, their theoretical capacity per physical area was comparable to or higher than hypothetical pure graphite and P film electrodes having the same thickness. After the large irreversible capacity loss in the first charge/discharge process, the samples showed relatively reversible charge/discharge characteristics. All samples showed no separation of the plating layer and no detectable micro-cracks after cycling. When the charge cut-off voltage was adjusted, their capacity retention could be improved significantly. The electrochemical result was just about the same before and after mechanical bending with respect to the overall shape of voltage curve and capacity.

Effect of Doping on the Ionic Conductivity of Li$_2$Po$_{4-x}$N$_{x}$ thin Film (Li$_2$Po$_{4-x}$N$_{x}$ 박막의 이온전도도에 미치는 Ti 첨가)

  • 이재혁;이유기;박종완
    • Journal of the Korean institute of surface engineering
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    • v.30 no.4
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    • pp.255-261
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    • 1997
  • Thin film batteries can be used as a micro power source for electronic in which minute power is needed. In this study, lithium phosphorous oxynitride(LIPON) thin films were deposited as an eletrolyte for lithium ion batteries using RF magentron sputtering of lithium phosphate in N2. Ti was also added into the LIPON films as a second network former to enhance the ioinc conductivity of the films. The optimum conditions for LIPON film deposition were sought and the electrolyte with the conductivity of $2.5 \times 10^{-6}$S/cm was obtained at the condition of RF power 4.4 W/$\textrm{cm}^2$, process pressure 10 mtorr and pure nitrogen ambience. Furthermore, the conductivity of LIPON films was increased from $2.5 \times 10^{-6}$S/cm to $8.6 \times 10^{-6}$S/cm by the doping of 2.4at.% Ti. It was also found that by adding Ti to LIPON films, Li content was increased and nitrogen content that reported having the cross-linking effect on LIPON films was also increased as confirmed XPS.

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