• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.11a
• /
• pp.289-289
• /
• 2009

The series hybrid propulsion system in bimodal tram consists of CNG engine, generator, inverter, motor and battery as main components. Among them, battery is very important thing to make a hybrid bimodal tram more efficient in driving. Battery pack is composed of 168 LPB(lithium polymer battery) cells, 650Vdc-300A. LPB should be treated with a good consideration in both temperature and overvoltage. This paper had analyzed and investigated the thermal flow and distribution of LPB module(l4 LPB cells) and Pack in simulated environments by commercial thermal analysis tool.

• Journal of Power Electronics
• /
• v.13 no.4
• /
• pp.569-583
• /
• 2013

In this study, the simultaneous use of a multi-level converter (MLC) as a DC-motor drive and as an active battery cell balancer is investigated. MLCs allow each battery cell in a battery pack to be independently switched on and off, thereby enabling the potential non-uniform use of battery cells. By exploiting this property and the brake regeneration phases in the drive cycle, MLCs can balance both the state of charge (SoC) and temperature differences between cells, which are two known causes of battery wear, even without reciprocating the coolant flow inside the pack. The optimal control policy (OP) that considers both battery pack temperature and SoC dynamics is studied in detail based on the assumption that information on the state of each cell, the schedule of reciprocating air flow and the future driving profile are perfectly known. Results show that OP provides significant reductions in temperature and in SoC deviations compared with the uniform use of all cells even with uni-directional coolant flow. Thus, reciprocating coolant flow is a redundant function for a MLC-based cell balancer. A specific contribution of this paper is the derivation of a state-space electro-thermal model of a battery submodule for both uni-directional and reciprocating coolant flows under the switching action of MLC, resulting in OP being derived by the solution of a convex optimization problem.

• Transactions of the Korean hydrogen and new energy society
• /
• v.15 no.1
• /
• pp.1-11
• /
• 2004

Hybrid power systems with fuel cells and batteries have the potential to improve the operation efficiency and dynamic response. A proper load management strategy is important to better system efficiency and endurance in hybrid systems. In this paper, a fuzzy logic algorithm has been used to determine the fuel cell output power depending on the external required power and the battery state of charge(SoC). If the required power of the hybrid system is small and the SoC is small, then the greater part of the fuel cell power is used to charge the battery pack. If the required power is relatively big and the SoC is big, then fuel cell and battery are concurrently used to supply the required power. These IF-THEN operation rules are implemented by fuzzy logic for the energy management system of hybrid system. The strategy is evaluated by simulation. The results show that fuzzy logic can be effectively used to optimize the operational efficiency of hybrid system and to maintain the battery SoC properly.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.22 no.3
• /
• pp.179-185
• /
• 2014

Average temperature and temperature uniformity in a battery cell are the important criteria of the thermal management of the battery pack for hybrid electric vehicles and electric vehicles (HEVs and EVs) because high power with large size cell is used for the battery pack. Thus, liquid cooling system is generally applied for the HEV/EV battery pack. The liquid cooling system is made of multiple cooling plates with coolant flow paths. The cooling plates are inserted between the battery cells to reject the heat from batteries to coolant. In this study, the cooling plate with U-shaped coolant flow paths is considered to evaluate the effects of coolant flow condition on the cooling performance of the system. The counter flow and parallel flow set up is compared and the effect of flow rate is evaluated using CFD tool (FLUENT). The number of counter-flows and flow rate are changed and the effect on the cooling performance including average temperature, differential temperature, and standard deviation of temperature are investigated. The results show that the parallel flow has better cooling performance compared with counter flow and it is also found that the coolant flow rate should be chosen with the consideration of trade-off between the cooling performance and pressure drop.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.56 no.10
• /
• pp.1763-1769
• /
• 2007

To improve the cycle-life and efficiency of an energy storage system for HEV, a dynamic control system consisted of a switch between a battery and an ultracapacitor module is proposed, which is appropriate for mild hybrid vehicle with 42V power net. The switch can be controlled based on the status of the battery and the ultracapacitor module, and a control algorithm that could largely decrease the number of high charging current peak is also implemented. Therefore the cycle life of the battery can be improved such that it is suitable for a mild hybrid vehicle with frequent engine start-stop and regenerative-braking. Also, by maximizing the use of the ultracapacitor, the system efficiency during high current charging and discharging operation is improved. Finally, this system has the effects that improves the efficiency of energy storage system and reduces the fuel consumption of a vehicle. To verify the validity of the proposed system, this paper presented cycles test results of different energy storage systems: a simple VRLA battery, hybrid energy Pack (HEP, a VRLA battery in Parallel with Ultracapacitor) and a HEP with a switch that controlled by energy management system (EMS). From the experimental result, it was proved the effectiveness of the algorithm.

• Journal of the Korean Electrochemical Society
• /
• v.25 no.3
• /
• pp.119-124
• /
• 2022

Because high power with large size cell is used for the battery pack of hybrid electric vehicles and electric vehicles (HEV and EV), average temperature in a battery cell is the important criteria of the thermal management of the battery pack. Furthermore, fast charging technology is required to reduce battery charging time. Since battery pack performance and lifespan are deteriorated due to the heat of cells and electronic components caused by fast charging, an effective cooling system is required to reduce performance deterioration. In this study, a cooling system and module design applied to a pouch-type for fast charging battery cell are investigated, and the cooling performance that can maximize the efficiency of the battery was analyzed. The result shows that the vapor chamber cooling system has better cooling performance, the temperature drop in the module was 5.82 ℃ compared with aluminum cooling plates.

• Proceedings of the KIEE Conference
• /
• 2001.07b
• /
• pp.1322-1324
• /
• 2001

FuelCell/Battery hybrid power systems were studied to develop high efficient zero-emission fuel cell electric vehicles. Fuel cells were used as an auxiliary energy source and batteries were used as a transient power source. The fuel cell system is used to supply the average power demand. Dynamic response of the hybrid systems was simulated using PSPICE program and also tested experimentally. The results can be used to design the interface module and to determine the power requirement between the fuel cell unit and the battery pack.

• Proceedings of the KIEE Conference
• /
• 2000.07d
• /
• pp.3081-3083
• /
• 2000

Fuel cell/battery hybrid power systems were studied to develop high efficient zero-emission fuel cell electric vehicles, Fuel cells were used as an auxiliary energy source and batteries were used as a transient power source. The fuel cell system is used to supply the average power demand. Dynamic response of the hybrid systems was simulated using PSPICE program and also tested experimentally, The results can be used to design the interface module and to determine the power requirement between the fuel cell unit and the battery pack.

• Journal of Electrical Engineering and Technology
• /
• v.7 no.6
• /
• pp.932-939
• /
• 2012

This paper presents an equivalent circuit model of a LIPB (Li-Ion Polymer battery) for Hybrid Electric Vehicles (HEVs). The proposed equivalent circuit can be used to predict the charging/discharging characteristics in time domain as well as the impedance characteristic analysis in frequency domain. Based on these features, a one-cell model is established as a function of Depth of Discharge (DoD), and a 48-cell model for a battery pack was also established. It was confirmed by experiment that the proposed model predict the discharging and impedance (AC) characteristics quite accurately at different constant current levels. To check the usefulness of the proposed circuit, the model was used to simulate a motor driving circuit with an Insulated Gate Bipolar Transistor (IGBT) inverter and Brushless DC (BLDC) motor, and it is confirmed that the model can calculate the battery voltage fluctuation in time domain at different DoDs.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.7
• /
• pp.1740-1749
• /
• 2009

As mobile devices evolve and digital convergence trend is here to stay, mobile phones are built with multiple functions including cameras, MP3s, TVs and game consoles. As a consequence, such multi-functional mobile phones come to spend more power, facilitating development of next-generation ultra-capacity lithium ion battery. In addition, environmental regulations and rising oil prices cause demand for hybrid cars to keep rising. Accordingly, more and more attention is being paid to medium and large batteries and more efforts are being made to realize lower battery prices, higher outputs and stability. This study presented a patent technology related to the lithium ion battery packing that allows reducing processes related, increasing productivity and recycling parts other than the body. The lithium ion battery pack to which protection circuits are elastically attached provides short circuit protection for the circuit and the body and makes electric connection of the circuit and the body easier.