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Characteristics of public quick chargers to support EV users December 8, 2010 TEPCO Takafumi Anegawa Slide 2 1.Why public chargers are necessary? 2.How much kW is optimal output power? 3.Does quick charger degrade battery? 4.Is there negative impact on power grid? 1.How can we deploy quick chargers? Slide 3 EV drivers can not use full battery capacity Driving Range (km) % of drivers Driving range Comfort DiscomfortFearfulness Typical distribution of daily driving range Slide 4 15km March 2008 Driver knew that EV could but didnt use it (October 2007) 8km Drive mileage was 203km before quick charger installation. Driver understood EV performance but they were reluctant to use it. Slide 5 15km 8km Drive mileage was drastically increase to 1472km after quick charger installation. Quick charger removed range anxiety (July 2008) Slide 6 Daily base driving distance is less than 100km in most cases then current EV can cover it easily.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.However, drivers are uncomfortable if remaining driving range become less than 50km. Public quick chargers relieve drivers range anxiety,Public quick chargers relieve drivers range anxiety, and drivers use quick chargers only few times. and drivers use quick chargers only few times. Why public chargers are necessary? Slide 7 1.Why public chargers are necessary? 2.How much kW is optimal output power? 1.Does quick charger degrade battery? 2.Is there negative impact on power grid? 1.How can we deploy quick chargers? Slide 8 Public charging stations in California - 129 in San Francisco and Bay Area - 186 in Los Angels County - Inductive and conductive are mixed - Output power is around 5kW - Charging time is around 2hrs for 70km - Price is about $3,000 without installation cost. - Private charger design is same of public one. 700km InductiveConductive Slide 9 Charger Output Power ( ) Charging time for 80km range (min) Optimal output of public charger Charger cost (k$) Cost is high. Charging time isnt so short. Waiting time is too long. Optimalpower Slide 10 Target charging time 5 minutes for 40km driving range 5 minutes for 40km driving range 10 minutes for 60km driving range 10 minutes for 60km driving range Specifications -Type: Switching type constant current power supply constant current power supply - Input: 3-phase 400V - Output power: 50kW (10~100kW) - Maximum DC output Voltage: 500V - Output current: 125A (20~200A) Unit price 20,000~30,000 Installation cost ~20,000 Specification of developed quick charger Cost for one user 250 = 50,000 200 users 250 = 50,000 200 users Slide 11 Waiting time should be less than 15min.Waiting time should be less than 15min. Additional driving range is 30km~60km which is equivalent of 5~8kWh.Additional driving range is 30km~60km which is equivalent of 5~8kWh. 50kW power can meet 10~15min recharging time.50kW power can meet 10~15min recharging time. Less than 20kW is too slow.Less than 20kW is too slow. More than 80kW is too costly and charging time doesnt become so short. More than 80kW is too costly and charging time doesnt become so short. How much kW is optimal power? Slide 12 1.Why public chargers are necessary? 2.How much kW is optimal output power? 1.Does quick charger degrade battery? 2.Is there negative impact on power grid? 1.How can we deploy quick chargers? Slide 13 BMS: Battery Management System Observing parameters Battery total voltage Cell voltage Battery temperature Input Current etc. Battery degradation is caused by over voltage and high temperature. Battery degradation is caused by over voltage and high temperature. Limit voltage and temperature depend on battery characteristics. Limit voltage and temperature depend on battery characteristics. On-board battery management system is watching the voltage and On-board battery management system is watching the voltage and the temperature in real time. the temperature in real time. Optimal charging speed is different in each batteries Slide 14 signal Communication Protocol Current Charging process is controlled by EV in CHAdeMO Problems: Battery improvement is so fast that its difficult to catch up every batteries data. Battery improvement is so fast that its difficult to catch up every batteries data. Standardization to meet lowest speed battery disturbs battery improvement. Standardization to meet lowest speed battery disturbs battery improvement. How CHAdeMO charger works: EV computer unit decides charging speed based on BMS observation. EV computer unit decides charging speed based on BMS observation. Charging current signal is sent to charger using CAN bus. Charging current signal is sent to charger using CAN bus. Charger supplies DC current following the request from EV. Charger supplies DC current following the request from EV. Connector Slide 15 CHAdeMO quick charger can change charging speed to meet each batteries characteristics and condition.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.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.Advanced battery which can absorb higher current can get higher power. Does quick charger degrade battery? Slide 16 1.Why public chargers are necessary? 2.How much kW is optimal output power? 1.Does quick charger degrade battery? 2.Is there negative impact on power grid? 1.How can we deploy quick chargers? Slide 17 Location of quick chargers on power grid Normal charging 50kVA Quick Charger Power Station Mall Low Voltage High Voltage Ultra High Voltage Residential Area 6.6kV 66kV >270 V Office Building 1200V Condo Substation 200kVA Trans Commercial Area 66kV Substation 50kVA Trans 5000kVA Trans 200V Slide 18 Slow AC for private and quick DC for public Charging Speed Fast Slow Public Private/Office People cannot wait for hours. EV users share quick chargers. Necessary number is ~100s Charging speed is most important. Location All EVs need their own outlets Necessary number is ~100,000s Low unit cost is most important. Slide 19 1.Why public chargers are necessary? 2.How much kW is optimal output power? 1.Does quick charger degrade battery? 2.Is there negative impact on power grid? 3.How can we deploy quick chargers? Slide 20 For public use 25 50 For private use Quick charger location in Japan ~300 chargers are in service Locations are on Google Map Search keyword is CHAdeMo Greater Tokyo Area Slide 21 TEPCO 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. Slide 22 Kanagawa prefecture office Operation started on June 2008 Slide 23 Office Building Operation started on September 2008 Operation started on April 2009 Operation started on September 2009 Slide 24 Metropolitan highway parking area Operation started on October 2008 Slide 25 Tokyo University of Marine Science and Technology Operation started on March 2009 Slide 26 Gas station Operation started on March 2009 Operation started on July 2009 Slide 27 Shopping mall Operation started on September 2008 Slide 28 Convenience store Operation started on December 2009 Slide 29 Mitsubishi Motors & Nissan Headquarter Operation started on June 2009 Operation started on August 2009 Slide 30 30 CHAdeMO Association Activities: 1.Establish technical specification of DC fast charger 2.Deploy DC fast chargers by sharing installation and operation experience among the members. Slide 31 Thank you Why dont you have a cup of tea