西安交通大学：《数值传热学》课程教学资源（课件讲稿）第十三章 FLUENT在基本流动与换热问题中的应用示例 13.5 Hybrid thermal management of Li-ion battery stack 锂电池组水气耦合热管理问题

13.5Hybrid thermalmanagement ofLi-ionbattery stack锂电池组水气耦合热管理问题Focus: Compared with previous examples, the focusof this example is thermal management of electricalenergy storagesystem.6/36

13.5 Hybrid thermal management of Li-ion battery stack 锂电池组水气耦合热管理问题 Focus: Compared with previous examples, the focus of this example is thermal management of electrical energy storage system. 6/36

13.5HybridthermalmanagementofLi-ionbattery stackKnown: A hybrid gas-liquid cooling method is usedfor thermal management of Li-ion battery stack. Thedomain and size is shown in Fig. 1. The boundaryconditions areasfollows:Inlet gas/Inletwater-velocity-inletOutlet-pressure-outletCell- a constant source termCellsize:120mmX200mmX50mmDiameter:20mmHeight:10mm7/36

13.5 Hybrid thermal management of Li-ion battery stack Known：A hybrid gas-liquid cooling method is used for thermal management of Li-ion battery stack. The domain and size is shown in Fig. 1. The boundary conditions are as follows: ◼ Outlet- pressure-outlet ◼ Inlet_gas/Inlet_water-velocity-inlet ◼ Cell- a constant source term Cell size：120 mm×200 mm×50 mm Diameter：20 mm Height：10 mm 7/36

Full charge open circuit voltage=4.303 VFull discharge open circuit voltage=3.841 VElectromotiveforce=4.07VAverage voltage=3.82 VWasteheatcoefficient-0.072Discharge power=230.47 WP=0.072X230.47=16.56WSource term=P/V-13800 W/m3Fig.1 Computational domain8/36

Fig.1 Computational domain Full charge open circuit voltage=4.303 V Full discharge open circuit voltage=3.841 V Electromotive force=4.07 V Average voltage=3.82 V Waste heat coefficient=0.072 Discharge power=230.47 W P=0.072×230.47=16.56 W Source term=P/V=13800 W/m3 8/36

Governing equations:The energy conservation equation for the battery cell canbe given as:aaTaTaaaTaT(kkkgeratOxaxOzaOz01Where p,Cp,and Tare the density, specific heat capacity andtemperature of the battery, respectively.k,,k, are the in-planethermal conductivity along the length and width direction ofwhich the values are identical, while k, is the cross-plane thermalconductivityalongthethickness direction9/36

Governing equations: The energy conservation equation for the battery cell can be given as: Where are the density, specific heat capacity and temperature of the battery, respectively. kx ,ky are the in-plane thermal conductivity along the length and width direction of which the values are identical, while kz is the cross-plane thermal conductivity along the thickness direction.  , ,and T CP ( ) ( ) ( ) P x y z gen T T T T C k k k Q t x x y y z z         = + + +        9/36

The energy conservation equation forwater/airis:d+V.(p.Cp.eVT )=V.(k.VT.)0The mass conservation eguation and momentumbalance equation for water/airis:av-VP+LV?VV.V=ODatWhere Pe, Cp.c, k. and T, are the density, specific heat capacity,thermal conductivity and temperature of the coolant. is thevelocity vector of the coolant. P and μ are the static pressure anddynamic viscosity of the cooling medium.10/36

The energy conservation equation for water/air is: The mass conservation equation and momentum balance equation for water/air is: , , ( ) c c p c c p c c c c T C C v T k T t    →   +  =        Where ρc , Cp,c, kc and Tc are the density, specific heat capacity, thermal conductivity and temperature of the coolant. 𝑣 Ԧ is the velocity vector of the coolant. P and μ are the static pressure and dynamic viscosity of the cooling medium. v 0 →  = 2 c v v v P v t   →    → → →     +  = − +           10/36