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Chulyoung Choi(최철영),Woongchul Choi(최웅철) 대한전기학회 2017 전기학회논문지 Vol.66 No.12
Global automobile manufacturers are developing electric vehicles (EVs) to eliminate the pollutant emissions from internal combustion vehicles and to minimize fossil fuel consumptions for the future generations. However, EVs have a disadvantage of shorter traveling distance than that of conventional vehicles. To answer this shortfall, more batteries are installed in the EV to satisfy the consumer expectation for the driving range. However, as the energy capacity of the battery mounted in the EV increases, the amount of heat generated by each cell also increases. Naturally, a better battery thermal management system (BTMS) is required to control the temperature of the cells efficiently because the appropriate thermal environment of the cells greatly affects the power output from the battery pack. Typically, the BTMS is divided into an active and a passive system depending on the energy usage of the thermal management system. Heat exchange materials usually include gas and liquid, semiconductor devices and phase change material (PCM). In this study, an application of PCM for a BTMS was investigated to maintain an optimal battery operating temperature range by utilizing characteristics of a PCM, which can accumulate large amounts of latent heat. The system was modeled using Dymola from Dassault Systems, a multi-physics simulation tool. In order to compare the relative performance, the BTMS with the PCM and without the PCM were modeled and the same battery charge/discharge scenarios were simulated. Number of analysis were conducted to compare the battery cooling performance between the model with the aluminum case and PCM and the model with the aluminum case only.
권미혜(Mi Hye Kwon),김광일(Kwang Il Kim),권혁주(Hyuck Ju Kwon),정진규(Jin Kyu Jung) 대한설비공학회 2018 대한설비공학회 학술발표대회논문집 Vol.2018 No.11
In this paper, the performance prediction model of the automotive oil cooler was developed using the Modelica language, and its applicability to actual work was confirmed. In particular, the program was completed by applying Dymola & Modelon Library as one-dimensional analysis approach. Numerical analysis results from Modelica based performance prediction program are also compared with experimental results. The results are well matched within +/-3%, and can be usefully used to establish product development direction at the initial design stage. And also this program can be usefully used in RFI/RFQ stage quickly. Modelica-based TOC performance prediction codes are also expanded to stacked plate type and air-cooled type.
구자군,양휘주,차용길,유상석 한국자동차공학회 2022 International journal of automotive technology Vol.23 No.6
In designing the heat exchanger model, the existing epsilon-number of transfer units (NTU) method cannot reflect factors inside the heat exchanger, such as the local flow rate changes. Furthermore, it is difficult to apply a three-dimensional model to a one-dimensional analysis since high computational power is required. In contrast, a pseudo-three-dimensional heat exchanger model which has higher accuracy than the existing epsilon-NTU method and has faster speed for application in one-dimensional analysis. However, pseudo-three-dimensional model has still improvements in the simulation time as the mesh counts increase. In this study, the improved pseudo-three-dimensional heat exchanger model was developed and integrated within a one-dimensional analysis loop capable of simulating vehicle driving and the cooling system. The integrated model calculated the change in the energy consumption of the entire cooling system with the change in the aspect ratio of the heat exchanger. Also, the optimal operation strategy of the cooling system, which incorporated a proportional integral derivative controller of the three-way valve, was determined to reduce the parasitic losses. As a result, parasitic loss of the cooling system decreased by 14.1 % as aspect ratio increased by 46 % under FTP-72 (UDDS) driving schedule and simulation time was reduced 90.1 % while accuracy degrades only 2.7 %.
xEV 배터리 열관리 시스템의 성능 향상을 위한 PCM 연구
최철영(Chulyoung Choi),조형민(Hyungmin Cho),김정용(Jeongyong Kim),최웅철(Woongchul Choi) 한국자동차공학회 2016 한국자동차공학회 학술대회 및 전시회 Vol.2016 No.11
It is a trend that is being released is an electric vehicle equipped with a battery of large capacity in order to overcome the disadvantage of a short driving distance the electric vehicle, and meets the needs of the consumer. The battery pack of large capacity is to increase the cell density, it caused a relatively high temperature depending on the charging / discharging, and the running conditions. The battery thermal management element is a great influence on the performance of the vehicle as well as being directly related to the life of the battery driving possible distance. Thus, there is a need for BTMS to effectively manage the control of the temperature of the cell entering the electric vehicle. BTMS is divided into Active and Passive, depending on how the power consumption, in a medium that is used is air and the fluid, a semiconductor device, such as PCM. In this paper, the minimum temperature difference between the battery cells from entering the electric vehicle, and in consideration of the battery life will be possible to interpret the BTMS optimum temperature control. We used the Dassault Systems Inc. Dymolar to build the system, modeled the BTMS to leverage the characteristics of the phase change material (PCM), which can accumulate thermal energy a large amount to maintain the battery life, and optimal operating temperatures. To compare the performance PCM, BTMS was constructed by modeling the air-cooling method using the cooling pin. By performing a charge / discharge simulations, conducted a study to compare the temperature of the battery and a heat management compared to the cooling pin and the PCM temperature.