OHP Cooling System Design for Li-Ion Battery

Researchers from Chungbuk National University developed an Oscillating Heat Pipe (OHP) system as a battery cooling module

Increasing concerns regarding climate change has led to increasing research and adoption of electric vehicles (EVs). The specific mixture of power generation sources used for driving can determine the CO2 intensity of EVs. According to International Energy Agency’s (IEA) 2017 report, in 2015, electric cars in Europe emitted ~50% less CO2 than gasoline cars and 40% less than diesel cars. OHP is a highly efficient and simple-structured type of heat pipe and contains a curved channel and working fluid.

Now, a team of researchers from Chungbuk National University assessed an OHP battery cooling system for a Li-ion battery with a long evaporator section with a condenser directly contacting the cold plate surface in bottom cooling mode. The team also evaluate the efficiency of the system’s operating parameters. The experimental setup consists of an OHP, a heater, a DC-power supply, a water flowing cooling plate, and a multichannel data acquisition system. The average temperature of the heater was maintained at around 55 °C as a design goal.

Following parameters meet the basic requirements for battery cooling: Outer diameter: 2 mm, inner diameter: 1 mm, heating of heater = 14 W, the coolant inlet point) = 25 °C, and Volume fraction, ((Volume of charged working fluid)/ (Total volume of OHP)) × 100% = 9.8%. The team found that the OHP can be operated normally when the α-angle (or β) was in the range 1–5°. Increase in the angle led to unstable operation with large intermittent fluctuations. The thermal efficiency and stability of the OHP system was optimal under the same heating and cooling conditions. Moreover, the efficiency of heat transfer of the OHP system relied on the filling rate of the working fluid. Increase in heating rate led to higher optimal VF. The research was published in the journal MDPI Energies on May 5, 2019.

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