Page - 132 - in Emerging Technologies for Electric and Hybrid Vehicles

Energies 2016,9, 563 over theSOCforvarious temperatures. It is noticeable that the lower theoperating temperatures, thehigher thedifferencebetweencharginganddischarging. ȱ Figure5.ChargeanddischargeOCVcurvesoverSOC. 5.2.DrivingTests on theRealVehicle Theobjective of a real test is to finda real drivingmaneuver reference signal to validate the batterymodelperformance. Nevertheless, thebatterymodel shouldbeable to simulate theactual system in real operating conditions, not merely charging-discharging cycles. Two driving tests wereperformedwith the testvehicle for thepurposeof investigation thesystemandcollecting the experimentaldata. The testswereexecutedonthe testinggroundatKarlsruheInstituteofTechnology (KIT).TheexperimentaldataattainedfromtheCANbusaredisplayedinFiguresA1andA2inthe AppendixA.2. Then, thedatawereprocessed inMATLAB. In thefirst test, thevehiclewasdriven inacounterclockwisecirculardirectionforabout230s. Thenthedirectionfordrivingwasreversed andthe testwasresumed.Avariablepedal inputwas implemented inorder tocoverabroaderrange ofdata. This test representsanaggressivedrivingscenario, leadingtodischargerateofupto3.4C. The second testwas implementedby subjecting thevehicle to a sequenceof suddenaccelerations anddecelerations. These testswereperformed thisway to createhighlyfluctuating signals in the batterysystem,whichareshowninFigure6. Thedynamicresponsesofbatteryvoltagecanbeusedto evaluate thebatterymodels,discussedabove. (a)ȱ (b) ȱ (c)ȱ ȱ (d) 0 50 100 150 200 250 300 350-100 -50 0 50 100 150 200 250 Time[s] 0 50 100 150 200 250 300 350320 330 340 350 360 370 380 Time[s] 0 50 100 150 200-50 0 50 100 150 200 250 Time[s] 0 50 100 150 200330 340 350 360 370 380 Time[s] Figure6.CANbusmeasurements: (a)Batterypackcurrent for thecirculardrivingtest; (b)Batterypack voltage for thecirculardriving test; (c)Batterypackcurrent for therapidaccelerationanddeceleration drivingtest; (d)Batterypackvoltage for therapidaccelerationanddecelerationdrivingtest. 132