• Proceedings of the KIPE Conference
• /
• 2014.07a
• /
• pp.528-529
• /
• 2014

본 논문은 리튬-이온 배터리의 OCV 예측기법에 대해서 제안하였다. OCV는 배터리의 SOC를 추정할 때 중요한 정보이다. 하지만, 정확한 OCV를 측정하기 위해서는 최소 30분 이상의 휴지시간이 소요된다는 단점을 가지고 있다. 따라서 본 논문은 이런 단점을 해결하기 위해 OCV 예측기법에 대해서 제안하였다. 제안한 OCV 예측기법의 타당성은 배터리 모델의 OCV와 예측된 OCV를 비교하는 시뮬레이션 통해 검증하였다.

• Korean Chemical Engineering Research
• /
• v.57 no.6
• /
• pp.768-773
• /
• 2019

The Fenton reaction, which evaluates the electrochemical durability of polymer membranes of polymer electrolyte fuel cells (PEMFC), and the degradation of polymer membranes by OCV holding method are compared. The Fenton reaction is a method that can evaluate the chemical durability of the polymer membrane at outside the cell in a shorter time than the OCV Holding method. The Fenton reaction was carried out at 30% hydrogen peroxide, 10 ppm iron, and $80^{\circ}C$ for 24 hours. OCV Holding was driven at $90^{\circ}C$, 30% relative humidity and OCV for 168 hours. The Fenton reaction caused a lot of degradation inside the polymer membrane. On the other hand, in OCV Holding, the membrane thickness was thinned by the entire surface and internal degradation. The fluorine emission rate was more than 10 times higher than that of OCV Holding due to the Fenton reaction. The hydrogen permeation rate increased about 30% at 24 hours of Fenton reaction. At OCV Holding, hydrogen permeability decreased after 24 hours and then increased. As a whole, there was a difference in a membranes deteriorated by Fenton reaction and OCV Holding.

• Journal of Korean Academy of Fundamentals of Nursing
• /
• v.7 no.3
• /
• pp.429-440
• /
• 2000

The purpose of this study was to validate self care outcomes included Nursing Outcomes Classification(NOC) developed by Johnson and Maas at the University of Iowa. A sample of 103 nurse experts working in university affiliated hospitals participated in this study. They were asked to rate indicators that examplified the outcomes on a scale of 1(indicator is not at all characteristic) to 5(indicator is very characteristic). A questionnaire with an adaptation of Fehring's methodology was used to establish the content validity of outcomes. The results were as follows : 1. All indicators were considered to be 'supporting' and no indicators were considered to be 'nonsupporting'. 2. 'Self care: Toileting' attained an OCV score of 0.884 and was the highest OCV score among self care outcomes. 3. 'Self care: Oral Hygiene' attained an OCV score of 0.756 and was the lowest OCV score among self care outcomes. 4. 'Self-care: Activities of Daily Living (ADL)' attained an OCV score of 0.845 and the highest indicator was 'eating'. 5. 'Self-care: Bathing' attained an OCV score of 0.810 and the highest indicator was 'washes body'. 6. 'Self-care: Dressing' attained an OCV score of 0.831 and the highest indicator was 'buttons clothing'. 7. 'Self-care: Eating' attained an OCV score of 0.815 and the highest indicator was 'chews food'. 8. 'Self-care: Grooming' attained an OCV score of 0.833 and the highest indicator was 'combs or brushes hair'. 9. 'Self-care: Hygiene' attained an OCV score of 0.823 and the highest indicator was 'washes hands'. 10. 'Self-care: Insrumental Activities of Daily Living(IADL)' attained an OCV score of 0.776 and the highest indicator was 'uses telephones'. 11. 'Self-care: Non-Parenteral Medication' attained an OCV score of 0.796 and the highest indicator was 'identifies medication'. 12. 'Self-care: Parenteral Medication attained an OCV score of 0.810 and the highest indicator were 'identifies medication' and 'administers medication correctly'. More outcomes need to be validated and outcomes sensitive to Korean culture need to be developed.

• Proceedings of the KIPE Conference
• /
• 2019.07a
• /
• pp.445-446
• /
• 2019

전기적 등가회로의 모델의 정확도 향상을 위하여 정확한 내부 저항과 OCV의 반영은 필수적이며, 이를 위한 OCV 실험에서 SOC 구간을 작게 작을수록 OCV의 정확도는 향상되지만 실험시간은 증가한다. 따라서 실험 시간을 고려한 적당한 SOC(5%, 10%) 구간으로 실험을 진행하며, 측정 되지 않은 영역의 내부 파라미터는 선형보간법으로 등가회로 모델에 반영한다. 이러한 문제로, 본 연구는 SOC 추정에의 주요 인자인 OCV의 추정 기법으로 뉴럴 네트워크(Neural Network)를 사용하였다. 추정 방법은 뉴럴 네트워크로 기존 OCV 실험 데이터를 학습하여 모델을 구축한다. 학습 모델의 입력값으로 용량 실험 데이터의 전압, 전류를 적용하였고 결과로 얻은 SOC-OCV 곡선을 비교 분석하였다.

• Journal of Korean Academy of Nursing Administration
• /
• v.6 no.3
• /
• pp.357-374
• /
• 2000

The purpose of this study was to validate knowledge outcomes included Nursing Outcomes Classification(NOC) developed by Johnson and Maas at the University of Iowa. A sample of 71 nurse experts working in university affiliated hospitals participated in this study. They were asked to rate indicators that examplified the outcomes on a scale of 1(indicator is not all characteristic) to 5(indicator is very characteristic). A questionnaire with an adaptation of Fehring's methodology was used to establish the content validity of outcomes. The results were as follow: 1. All indicators were considered to be 'supporting' and no indicators were considered to be 'nonsupporting'. 2. 'Knowledge: Treatment Regimen' attained and OCV score of 0.816 and was the highest OCV score among outcomes. 3. 'Knowledge: Energy Conservation' attained an OCV score of 0.748 and was the lowest OCV score among abuse outcomes. 4. 'Knowledge: Breastfeeding' attained an OCV score of 0.790 and was the highest indicator was 'description of benefits of breastfeeding'. 5. 'Knowledge: Child Safety' attained an OCV score of 0.778 and was the highest indicator was 'demonstration of first aids techniques'. 6. 'Knowledge: Diet' attained an OCV score of 0.779 and was the highest indicator was 'performance of self-monitoring activities'. 7. 'Knowledge: Disease Process' attained an OCV score of 0.815 and was the highest indicator was 'description of signs and symptoms'. 8. 'Knowledge: Health Behaviors' attained an OCV score of 0.800 and was the highest indicator was 'description of safe use of prescription drugs'. 9. 'Knowledge: Health Resources' attained an OCV score of 0.794 and was the highest indicator was 'description of need for follow-up care'. 10. 'Knowledge: Infection Control' attained an OCV score of 0.793 and was the highest indicator was 'description of signs and symptoms'. 11. 'Knowledge: Medication' attained an OCV score of 0.789 and was the highest indicator was 'description of correct administration of medication'. 12. 'Knowledge: Personal Safety' attained an OCV score of 0.804 and was the highest indicator was 'description of measures to reduce risk of accidental injury'. 13. 'Knowledge: Prescribed Activity' attained an OCV score of 0.810 and was the highest indicator was 'proper performance of exercise'. 14. 'Knowledge: Substance Use Control' attained an OCV score of 0.809 and was the highest indicator was 'description of signs of dependence during substance withdrawl'. 15. 'Knowledge: Treatment Procedure(s)' attained an OCV score of 0.795 and was the highest indicator was 'description of appropriate action for complications'. 16. 'Knowledge: Treatment Regimen' attained an OCV score of 0.816 and was the highest indicator was 'description of self-care responsibilities for emergency situations'. More outcomes need to be validated and outcomes sensitive to Korean culture need to be developed.

• Journal of Power Electronics
• /
• v.10 no.2
• /
• pp.181-186
• /
• 2010

This paper presents a new method for the estimation of State of Charge (SOC) for NiMH batteries. Among the conventional methods to estimate SOC, Coulomb Counting is widely used, but this method is not precise due to error integration. Another method that has been proposed to estimate SOC is by using a measurement of the Open Circuit Voltage (OCV). This method is found to be a precise one for SOC estimation. In NiMH batteries, the hysteresis characteristic of OCV is very strong compared to other type of batteries. Another characteristic of NiMH battery to be considered is that the OCV of a NiMH battery under discharging mode is lower than it is under charging mode. In this paper, the OCV is modeled by a simple method based on a hyperbolic function which well known as Takacs’s model. The OCV model is then used for SOC estimation. Although the model is simple, the error is within 10%.

• Korean Chemical Engineering Research
• /
• v.45 no.4
• /
• pp.345-350
• /
• 2007

During PEMFC operation, OCV(open circuit voltage) and low humidity conditions accelerate the degradation of perfluorosulfonic acid membrane. There have been no studies that clearly explain why these conditions accelerate the membrane degradation. In this study, the hydrogen permeability through the membrane, I-V polarization of MEA, fluoride emission rate(FER) and $H_2O_2$ concentration in condensed water were measured during cell operation under OCV and low relative humidity(RH). The experimental results were evaluated with oxygen radical mechanism the most commonly known for membrane degradation. It seems that low RH of anode is a good condition for $H{\cdot}$ radical formation on the Pt catalyst and the OCV condition accelerate the $H{\cdot}$ to form $HO_2{\cdot}$ radical attacking the polymer membrane.

• Proceedings of the KIPE Conference
• /
• 2011.11a
• /
• pp.301-302
• /
• 2011

본 논문에서는 리튬 폴리머 배터리($LiFePO_4/C$)의 개방전압(OCV;open-circuit voltage) 히스테리시스 특성을 이용한 확장 칼만 필터(EKF;extended Kalman filter) 기반 state-of-charge(SOC) 추정방법을 소개한다. 배터리 등가회로의 중요 요소인 OCV 모델링을 위해 충전 및 방전 각각의 OCV 히스테리시스 특성을 고려하였고 더불어 OCV-SOC 관계의 SOC 간격을 10%에서 5%로 조정하여 EKF 기반 SOC 추정알고리즘의 성능이 향상되었다. 축소된 하이브리드 자동차용 전류프로파일을 적용했을 때 SOC 추정이 잘 이루어지지 않는 영역은 EKF의 측정방정식에 노이즈 모델 및 데이터 리젝션(data rejection)을 구축하였다. 제안된 방법을 이용하여 SOC 추정결과 전류적산법 대비 5%이내의 SOC 추정에러를 만족하였다.

• 한국신재생에너지학회:학술대회논문집
• /
• 2007.11a
• /
• pp.180-182
• /
• 2007

PEMFC의 상용화 진입에 있어서 걸림돌 중의 하나가 열화(degradation)에 의한 성능감소이다. PEMFC 고분자 막의 열화가 PEMFC 성능 감소에 많은 영향을 미친다. 고분자 막의 성능 감소 원인은 여러가지가 있지만 무가습/OCV조건에서 성능 감소가 잘 된다. 그 이유에 대해서는 OCV/무가습 조건에서 과산화수소나 라디칼이 많이 형성될 수 있다는 것과, OCV조건에서 사용되지 못하는 수소와 산소의 gas-crossover 가 많기 때문이라는 것 그리고 무가습 조건에서 수소와 산소의 분압이 높아 gas-crossover 가 유리하고 악의 건조에 따른 물리적인 영향 등등이 거론되고 있다. 본 연구에서는 같은 조건에서 Cell 운전온도가 막열화에 미치는 영향을 실험하였다. OCV 여려 조건 에서 단위전지 실험을 한 후 I-V, 수소 투과도, 임피던스, FER(fluoride emission rate)등을 측정해 그 결과를 검토 분석하였다. OCV/Anode 무가습 조건이 알려진 대로 막열화 가속조건 이었음을 확인하였고, 실험 결과 Cell 운전온도가 $10^{\circ}C$증가 할 때마다 FER(fluroide emission rate)이 즉 막 열화속도가 약 2배정도 증가함을 보였다.

• Korean Chemical Engineering Research
• /
• v.53 no.1
• /
• pp.6-10
• /
• 2015

Enzyme fuel cells were composed of enzyme anode and PEMFC cathode. Enzyme anodes was fabricated by compression of a mixture of graphite particle, glucose oxidase as a enzyme and ferrocene as a mediator, and then coated with Nafion ionomer. Open circuit voltage (OCV) were measured with variation of anode manufacture factors, to find optimum condition of enzyme anode. Optimum pressure was 9.0 MPar for enzyme anode pressing process. Highest OCV was obtained at 60% graphite composition in enzyme anode. Optimum glucose concentration was 1.7mol/l in anode substrate solution and enzyme activity of anode was stable for 7 days.