Underwater Environmental Impact and Thermal Management of Unmanned Underwater Vehicle Li-Ion Batteries

Abstract Lithium-ion (Li-ion) batteries have recently become the main source of power in portable devices due to advantages such as high energy density. However, Li-ion cells operate well only in a specific temperature range. Degraded preperformance is a consequence of low temperature operation, and potential fire risk originates from thermal runaway at elevated temperatures. Efficient thermal management of Li-ion cells and battery packs is essential to ensure safe and durable performance in wide temperature range. Thermoelectric coolers (TECs), which have been used widely for electronics cooling may also be appropriate for battery cooling due to size compactness, working with direct current. This paper presents experimental characterization of cooling of a prismatic test cell with TECs on two sides. Cooling effect of TEC on the cell core and surface temperatures is investigated at different TEC power rates. Results show core and surface temperatures of the test cell decrease significantly. The obtained results show that by applying the TEC, a temperature drop of 10 °C was achieved for 0.75A TEC current. The optimum TEC current can be selected based on the application. In addition, numerical simulations are carried out to compare with experimental measurements. Heating effect of mounted TECs can be easily achieved just by changing current direction. Experimental results reveal TECs can heat up a cell in cold climate shortly. In addition, thermo electric module may also offer insulating effect in cold climate. Results presented in this paper illustrate potential application of thermoelectric cooling for thermal management of Li-ion cells.

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Sizing and Dynamic Modeling of a Power System for the MUN Explorer Autonomous Underwater Vehicle Using a Fuel Cell and Batteries

Journal of Energy ◽

10.1155/2019/4531497 ◽

2019 ◽

Vol 2019 ◽

pp. 1-17 ◽

Cited By ~ 3

Author(s):

Mohamed M. Albarghot ◽

M. Tariq Iqbal ◽

Kevin Pope ◽

Luc Rolland

Keyword(s):

Fuel Cell ◽

Power System ◽

Autonomous Underwater Vehicle ◽

Underwater Vehicle ◽

Hydrogen Gas ◽

System Capacity ◽

Li Ion Batteries ◽

Li Ion ◽

Battery Bank ◽

Bank System

The combination of a fuel cell and batteries has promising potential for powering autonomous vehicles. The MUN Explorer Autonomous Underwater Vehicle (AUV) is built to do mapping-type missions of seabeds as well as survey missions. These missions require a great deal of power to reach underwater depths (i.e., 3000 meters). The MUN Explorer uses 11 rechargeable Lithium-ion (Li-ion) batteries as the main power source with a total capacity of 14.6 kWh to 17.952 kWh, and the vehicle can run for 10 hours. The drawbacks of operating the existing power system of the MUN Explorer, which was done by the researcher at the Holyrood management facility, include mobilization costs, logistics and transport, and facility access, all of which should be taken into consideration. Recharging the batteries for at least 8 hours is also very challenging and time consuming. To overcome these challenges and run the MUN Explorer for a long time, it is essential to integrate a fuel cell into an existing power system (i.e., battery bank). The integration of the fuel cell not only will increase the system power, but will also reduce the number of batteries needed as suggested by HOMER software. In this paper, an integrated fuel cell is designed to be added into the MUN Explorer AUV along with a battery bank system to increase its power system. The system sizing is performed using HOMER software. The results from HOMER software show that a 1-kW fuel cell and 8 Li-ion batteries can increase the power system capacity to 68 kWh. The dynamic model is then built in MATLAB/Simulink environment to provide a better understanding of the system behavior. The 1-kW fuel cell is connected to a DC/DC Boost Converter to increase the output voltage from 24 V to 48 V as required by the battery and DC motor. A hydrogen gas tank is also included in the model. The advantage of installing the hydrogen and oxygen tanks beside the batteries is that it helps the buoyancy force in underwater depths. The design of this system is based on MUN Explorer data sheets and system dynamic simulation results.

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Design of an Optimized Thermal Management System for Li-Ion Batteries under Different Discharging Conditions

Energies ◽

10.3390/en13215695 ◽

2020 ◽

Vol 13 (21) ◽

pp. 5695 ◽

Cited By ~ 1

Author(s):

Ankur Bhattacharjee ◽

Rakesh K. Mohanty ◽

Aritra Ghosh

Keyword(s):

Thermal Management ◽

Cooling System ◽

Peak Temperature ◽

Air Cooling ◽

Li Ion Batteries ◽

Li Ion Battery ◽

Liquid Cooling ◽

Thermal Management System ◽

Li Ion ◽

Liquid Cooling System

The design of an optimized thermal management system for Li-ion batteries has challenges because of their stringent operating temperature limit and thermal runaway, which may lead to an explosion. In this paper, an optimized cooling system is proposed for kW scale Li-ion battery stack. A comparative study of the existing cooling systems; air cooling and liquid cooling respectively, has been carried out on three cell stack 70Ah LiFePO4 battery at a high discharging rate of 2C. It has been found that the liquid cooling is more efficient than air cooling as the peak temperature of the battery stack gets reduced by 30.62% using air cooling whereas using the liquid cooling method it gets reduced by 38.40%. The performance of the liquid cooling system can further be improved if the contact area between the coolant and battery stack is increased. Therefore, in this work, an immersion-based liquid cooling system has been designed to ensure the maximum heat dissipation. The battery stack having a peak temperature of 49.76 °C at 2C discharging rate is reduced by 44.87% to 27.43 °C after using the immersion-based cooling technique. The proposed thermal management scheme is generalized and thus can be very useful for scalable Li-ion battery storage applications also.

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