Presentation on theme: "Characteristics of public quick chargers to support EV users"— Presentation transcript:
1Characteristics of public quick chargers to support EV users December 8 , 2010TEPCOTakafumi Anegawa
2Why public chargers are necessary? How much kW is optimal output power?Does quick charger degrade battery?Is there negative impact on power grid?How can we deploy quick chargers?
3EV drivers can not use full battery capacity Typical distribution of daily driving rangeComfortDiscomfortFearfulnessDriving rangeDriving range% of driversDriving rangeDriving Range (km)
4Driver knew that EV could but didn’t use it (October 2007)15kmMarch 20088kmDrive mileage was 203km before quick charger installation.Driver understood EV performance but they were reluctant to use it.
5Quick charger removed range anxiety (July 2008)15km8kmDrive mileage was drastically increase to 1472kmafter quick charger installation.
6Why public chargers are necessary? Daily base driving distance is less than 100km in most cases then current EV can cover it easily.However, drivers are uncomfortable if remaining driving range become less than 50km.Public quick chargers relieve drivers’ range anxiety,and drivers use quick chargers only few times.
7Why public chargers are necessary? How much kW is optimal output power?Does quick charger degrade battery?Is there negative impact on power grid?How can we deploy quick chargers?
8Public charging stations in California 129 in San Francisco and Bay Area186 in Los Angels CountyInductive and conductive are mixedOutput power is around 5kWCharging time is around 2hrs for 70kmPrice is about $3,000 without installation cost.Private charger design is same of public one.InductiveConductive700km
9Optimal output of public charger Cost is high.Charging time isn’t so short.Waiting time is too long.Charger cost (k$)Charging time for 80km range (min)OptimalpowerCharger Output Power (ｋＷ)
10Specification of developed quick charger SpecificationsType: Switching typeconstant current power supply- Input: 3-phase 400V- Output power: 50kW (10~100kW)- Maximum DC output Voltage: 500V- Output current: 125A (20~200A)Target charging time5 minutes for 40km driving range10 minutes for 60km driving rangeUnit price €20,000~30,000Installation cost ~€20,000Cost for one user€250 = €50,000 ÷ 200 users
11How much kW is optimal power? Waiting time should be less than 15min.Additional driving range is 30km~60km which is equivalent of 5~8kWh.50kW power can meet 10~15min recharging time.Less than 20kW is too slow.More than 80kW is too costly and charging time doesn’t become so short.
12Why public chargers are necessary? How much kW is optimal output power?Does quick charger degrade battery?Is there negative impact on power grid?How can we deploy quick chargers?
13Optimal charging speed is different in each batteries Battery degradation is caused by over voltage and high temperature.Limit voltage and temperature depend on battery characteristics.On-board battery management system is watching the voltage andthe temperature in real time.Observing parametersBattery total voltageCell voltageBattery temperatureInput Current etc.BMS: Battery Management System
14Charging process is controlled by EV in CHAdeMO Communication Protocol Problems:Battery improvement is so fast that it’s difficult to catch up every batteries’ data.Standardization to meet lowest speed battery disturbs battery improvement.How CHAdeMO charger works:EV computer unit decides charging speed based on BMS observation.Charging current signal is sent to charger using CAN bus.Charger supplies DC current following the request from EV.signalCommunication ProtocolCurrentConnector
15Does quick charger degrade battery? CHAdeMO quick charger can change charging speed to meet each batteries characteristics and condition.There is no negative impact on battery system by quick charging if charging speed is well controlled.Advanced battery which can absorb higher current can get higher power.
16Why public chargers are necessary? How much kW is optimal output power?Does quick charger degrade battery?Is there negative impact on power grid?How can we deploy quick chargers?
17Location of quick chargers on power grid Ultra High VoltageHigh VoltageLow Voltage>270 ｋVSubstationSubstation66kVPowerStation6.6kV66kV5000kVATrans50kVATrans200kVATransTrans３φ200V1φ200VMallCommercial AreaCondoOfficeBuildingResidential Area×Normal charging50kVA Quick Charger
18Slow AC for private and quick DC for public FastCharging SpeedEV users share quick chargers.Necessary number is ~100sCharging speed is most important.Private/OfficeLocationAll EVs need their own outletsNecessary number is ~100,000sLow unit cost is most important.Public×People cannot wait for hours.Slow
19Why public chargers are necessary? How much kW is optimal output power?Does quick charger degrade battery?Is there negative impact on power grid?How can we deploy quick chargers?
20Quick charger location in Japan For public useFor private useGreater Tokyo Area25ｋｍ50ｋｍ~300 chargers are in serviceLocations are on Google MapSearch keyword is “CHAdeMo”
21TEPCO branch office 64 quick chargers are installed. It will be 100 by the end of 2010.310 EVs are already deployed.210 EVs will be deployed in 2010.
22Kanagawa prefecture office Operation started onJune 2008
23Office Building Operation started on September 2008 Operation started on April 2009Operation started on September 2009
24Metropolitan highway parking area Operation started onOctober 2008
25Tokyo University of Marine Science and Technology Operation started on March 2009
26Gas station Operation started on Operation started on March 2009 July 2009