European Electric Vehicle Fleet Demonstration with Advanced Batteries
The 14th International Electric Vehicle Symposium (EVS-14)
December 11-17, 1997, Walt Disney World Dolphin
Orlando, Florida USA
R. Bady
Forschungsgesellschaft Kraftfahrwesen mbH Aachen
B. Kaufmann
Adam Opel AG
Technical Development Center Europe
Bahnhofsplatz 1, D - 65423 Ruesselsheim (Germany)
Dr. W. Bögel
GIE Renault Recherche et Innovation
14, av. Albert Einstein
ZI de Trappes-Elancourt, F - 78190 Trappes (France)
Dr. C.-H. Dustmann
AEG Anglo Batteries GmbH
Soeflinger Straße 100, D - 89007 Ulm (Germany)
P. van den Bossche
CITELEC, c/o VUB-tw-ETEC
Pleinlaan 2, B - 1050 Brussels (Belgium)
Abstract
Introduction
Project partners
Objectives of the project
Vehicle technology
Astra Impuls
Renault Express Thermie
Vehicle users
Data recording and evaluation
First experiences
Abstract
In April 1996 the European Project 'Electric Vehicle Fleet Demonstration with Advanced Batteries' has been started with financial support of the European Commission. The objectives of this commonly supported project are to test the performances of 16 electric vehicles equipped with sodium-nickel chloride batteries (ZEBRA batteries). Electric vehicles with "advanced batteries" have a practical range of more than 100 km which is enough for the majority of the daily city trip lengths. These electric vehicles do not need opportunity charging and can be recharged mainly over night during low power periods of the power generation plants. The use of off peak power improves the vehicle economy, the power plant efficiency and the utilization of the distribution system. The target of this project is to substitute a gasoline consumption of about 8,5 l/100 km (version with IC engines) by an electricity consumption of about 22,5 kWh/100 km in average per vehicle. The electric vehicles to be used for this demonstration project are 10 Opel Astra Caravan and 6 Renault Express. All together 34 battery blocks with 433 kWh battery capacity, which have been produced in the AABG pilot line, will be operated within the scope of this project. Prototypes of these vehicles have been built up, tested and qualified. The intention is to operate the vehicles in concentrated areas, therefore the vehicles will be used in 5 major European cities (Aachen/D, Liege/B, Maastricht/NL, Paris/F, Chambéry/F). The monitoring will enable an evaluation of the energy consumption structure, customer acceptance and battery endurance.
Introduction
With the support of the European Commission a new European Electric Vehicle Fleet Evaluation has been started in April 1996. The objectives of this commonly supported project are to test the performances of 16 electric vehicles equipped with sodium-nickel chloride batteries (ZEBRA batteries). Electric vehicles with "advanced batteries" have a practical range of more than 100 km which is enough for the majority of the daily city trip lengths. These electric vehicles do not need opportunity charging and can be recharged mainly over night during low power periods of the power generation plants. The use of off peak power improves the vehicle economy, the power plant efficiency and the utilization of the distribution system.
The intention is to operate the vehicles in concentrated areas, therefore 5 European cities in 4 European countries have been selected. The selected cities are (Figure 1):
• Aachen (Germany)
• Maastricht (Netherlands)
• Liège (Belgium)
• Paris (France)
• Chambéry (southern France)
Figure 1: Test Locations
Project partners
The project is commonly supported by five project partners. Furthermore the European Commission supports the project with 40% of the estimated budget within its Thermie program.
Project coordinator and battery manufacturer is AEG Anglo Batteries GmbH settled in Ulm, Germany. AEG Anglo has developed the ZEBRA battery and is now running a fully automated pilot line spread in three plants in Derby, Great Britain, Berlin and Ulm, Germany.
The OPEL International Technical Development Center in Ruesselsheim, Germany has developed the 'Astra Impuls' an electric vehicle based on the Astra series, the company's high volume car.
GIE Renault Recherche et Innovation in Trappes, France has selected the Renault Express for the project. The industrial EV equipped with a NiCd battery has been modified to integrate the ZEBRA battery system.
FKA Forschungsgesellschaft Kraftfahrwesen mbH Aachen, Germany an automotive research and consultants company accompanies the OPEL cars in the EUREGIO (the area where the borders of Germany, Belgium and the Netherlands meet) with its cities Aachen, Maastricht and Liège.
CITELEC the representation of cities interested in electric vehicles in Brussels, Belgium will develop criteria to monitor the acceptance of electric vehicles.
Objectives of the project
The objectives of this project are to test 16 electric vehicles (10 Opel Astra Impuls and 6 Renault Express) equipped with ZEBRA-Batteries manufactured by AEG Anglo Batteries GmbH. These sodium-nickel chloride based batteries have an energy density of more than 80 Wh/kg which will allow the cars a range of more than 100 km per day, therefore obviating the need for opportunity charging during the day and increasing the use of electricity at night. The target is to substitute a gasoline consumption of 8.5 l / 100 km by an electricity consumption of 22.5 kWh / 100 km in average per vehicle. Furthermore the user acceptance of EVs with high temperature batteries will be studied.
The vehicles are rented to commercial companies, municipal enterprises and private users to insure a day to day practical use.
The total duration of the project is 39 months, the fleet testing and monitoring will be approximately 26 months.
The project will allow:
· to measure on a limited statistical basis the day/night charging behavior of EV user having sufficient practical range of more than 100 km.
· to collect limited statistical data on life time of an "advanced battery" in practical day to day use
· to collect empirical data of the acceptability of modern electric vehicles by normal users.
Vehicle technology
Astra Impuls
The 10 Astra 'Impuls' used in the project represent the advanced stage of the third generation of electric vehicles developed by OPEL. The 'Impuls', is based on the model year 1996 Astra station wagon, an OPEL high volume production vehicle. This successful production car is a five seater with a payload up to 490 kg. Based on this car OPEL developed a vehicle that is with respect to volumetric and gravimetric payload capacity almost equal to the production vehicle.
To insure the high safety standards of the Astra series, several prototype 'Impuls' had to prove their reliability on Opel's test facilities in Dudenhofen and crash tests.
The Astra Impuls is equipped with two ZEBRA batteries (Z6 and Z5) which offer a range of approx. 120 to 150 km. For an evenly balanced weight distribution one battery block is under the bonnet, the other under the cargo floor, which had to be raised 60 mm. The nominal system voltage is 284 volts with an energy content of 25.9 kWh. Using the permanently installed on-board charging device (230 V connection) the charging time required is around ten hours when the battery is completely empty. The charging time is shorter if the batteries are only partially discharged, for instance about 6.5 hours are required to charge the vehicle for a range of 100 km.
Figure 2: Astra Impuls with components
The batteries weight of 325 kg (2 ZEBRA batteries 310 kg plus 15 kg for additional control components) increases the vehicle weight without payload to 1,400 kg. With the use of light weight materials such as aluminum wherever possible and the help of a special rear axle designed to compensate the additional empty weight, there are practically no reductions in payload as compared to the Astra Caravan with an internal combustion engine. The Astra Impuls with ZEBRA battery has a payload (= max. load weight beyond vehicle weight) of 450 kg.
The electric motor used is fitted with adapted control systems and is characterized by high torque values (130 Nm) with a wide rpm range. The comparative figures for an internal combustion engine, i.e. an Astra 1.6i with 52 kW / 71 metric hp. are maximum torque of 128 Nm at 2,800 rpm.
An inverter converts the battery DC current into 3-phase AC current. The compact 3-phase asynchronous motor develops a peak output of 42 kW based on the battery data. Power transfer is by means of a fixed ratio gearbox. The high torque from a standstill gives the Astra Impuls a very good acceleration characteristic, above all in the lower speed ranges. The car requires only 6 seconds to accelerate from 0 to 50 km/h. The top speed of the Astra Impuls is electronically limited to 120 km/h. During braking, the motor acts as a generator that returns energy to the battery (recuperation braking). The disc brakes are not actuated until the brake pedal is pushed down harder.
Slight changes were made to the interior. There is no need for a clutch pedal due to the wide rpm range of the motor.
A newly developed Electronic Shift Pad (ESP) replacing the mechanical selector lever raises the control comfort of the vehicle. The electronically controlled ESP (Figure 3) allows the integration of a lot of additional functions. It also decreases the weight compared to the former selection unit by 1.5 kg. The driver can switch between three power limitation stages. In 'Maximum Mode' the batteries are able to deliver up to 240 A, this allows a power output of 42 kW. In 'Normal Mode' the battery current is limited to 120 A, still giving the driver the possibility to travel at maximum speed of 120 km/h. In 'Economic Mode' it is always possible to use the full range of about 150 km. In case the driver needs full power a kickdown - function is integrated switching to 'Maximum Mode'.
Figure 3: Electronic Shift Pad (ESP) with displa showing the amount of charged energy distinguished by day (T:) and night (N:)
To prevent operating errors the ESP-electronics always checks input parameters against driving parameters, i.e. the reverse command is ignored at speeds above 15 km/h. The ESP changes to neutral automatically when the car is turned off. A shiftlock function allows the selection of the 'Drive'- and 'Reverse'-stage from 'Park'- and 'Neutral'-stage only when the brake is applied. A keylock-function automatically sets the parking mechanism when the ignition key is taken out to prevent the car from rolling away.
The integrated on-board computer also provides the driver with information such like cruising range, actual and average consumption in Watt-hours or as a sum of money, as well as information on the battery conditions.
Charging is also controlled by the ESP. The system offers the driver three different charging modes, to insure highest readiness of the car, lowest energy costs and highest efficiency of power generation. Next to the standard charging mode, that starts charging immediately after the car is plugged in, there is a charging mode optimized towards cruising range and another optimized toward 'off peak power'-times of the power plants. The user just has to tell the car what range he wants to cover during the rest of the day or at what time he needs a complete charge and the electronic will start charging at optimum time.
Renault Express THERMIE
The Express is a small delivery van currently commercialized by Renault with its IC engine equipment. The electric version of this vehicle is commercially available since beginning 1996.
This standard electric version is a two seater, equipped with Nickel/Cadmium batteries as power source, and a DC motor and chopper as powering system. The available continuous power is 15 kW with a maximum power of 25 kW. The vehicle accelerates from 0 - 50 km/h in under 10 seconds and reaches a top speed of 100 km/h. The NiCd battery provides a range of 80 to 100 km.
The vehicle rear architecture, for ZEBRA integration, as well as the electronic control system and the driver interface, have been modified, the front architecture of the car is remaining unchanged. The THERMIE vehicle (Figure 4) is a five seater compared to the two seater industrialized version of the electrified Express.
The on-board charger allows a complete recharge of the battery on any standard socket (220V/16A) within 6 to 8 hours, depending on the state of charge of the battery. A partial charge of 1 hour corresponds to a driving range of approximately 15 - 20 km.
Two types of vehicles have been realized:
· TYPE 1: Two-battery-system
2 ZEBRA batteries using the well-proven SL09 cell technology, with a system weight of 325 kg, an on-board energy of 25,5 kWh and a peak power of 22 kW at 80% DOD.
· TYPE 2: One-battery-system
1 ZEBRA battery using the recent ML cell technology, with a system weight of only 200 kg, an energy content of 18 kWh and a peak power of 26 kW at 80% DOD.
The different vehicle configurations offer different performance characteristics (Table 1):
Table 1
Performance characteristics Type 1 / Type 2 vehicle configuration
average range
Type1: 150 km, Type 2: 100 km
acceleration 0-50 km/h
Type 1: 10 sec, Type 2: 8 sec
payload
Type 1: 400 kg, Type 2: 530 kg
energy consumption
Type 1: 30 kWh/100 km, Type 2: 25 kWh/100 km
Due to the fact that each user has one vehicle of each type it is possible to study the user acceptance for the vehicles and to determine the real requirements for an EV.
Figure 4: RENAULT Express THERMIE
Vehicle users
After user selection criterion have been created the following users have been selected for participating in the project:
Aachen
• The City of Aachen, Department of internal postal service
• The City of Aachen, Department of structural engineering
• Kur- und Badegesellschaft mbH, company in charge for the installations of the spa
• Otto Geilenkirchen Pharm. Großhandlung, delivery service for pharmaceuticals
Maastricht
• The City of Maastricht, department of environment
• The City of Maastricht, environment police
• Maastricht Toelevrings Bedrijve, department of horticulture
• Stadsbus Groep N.V., Company running the city bus
Liège
• L'ASSOCIATION LIÈGEOISE D'ÉLECTRICITÉ, distributor of electric energy
• Centre Public d'Aide Sociale de Liège, City of Liège public welfare center
Paris area
• EDF local operating service in Versailles, Ile de France (2 vehicles)
• council administration in Le Plessis Robinson, Ile de France (2 vehicles)
Chambéry
• council administration and public transport services (2 vehicles)
For the Renault vehicles each user has one vehicle of each type - a) two-battery-system SL cell, b) one-battery-system ML cell - , allowing to compare the customer acceptance for the two different vehicle configurations.
Data recording and evaluation
The aim of the project is to evaluate the following data:
1. Energy consumption distinguished by day and night charging.
2. Battery capacity, OCV and internal resistance to be plotted over nominal cycles, calendar life and km. These are the relevant battery life data.
3. Customer acceptance by evaluation of the driving records and interviews.
For data recording the users are obliged to keep logbooks and report on their experiences. Furthermore each Opel Astra Impuls vehicle does have an integrated energy counter and a data logger. For cover data on the aging of the batteries, each vehicle will be tested every six months on a battery test bench according to special test procedures. Data like OCV, power capability will covered from these tests. For doing user acceptance studies questionnaires and individual interviews are being performed.
First experiences
After the development, building up and qualification of the prototypes since April 1996 the fleet has been started operating between April and June 1997. As first result can be noticed that all the users are very satisfied with their vehicle. Although it is the first time the users have been in contact with electric vehicles none of them has problems with the limited range or speed. The smooth and quite vehicle handling and the easy operation of the vehicles have been praised by several users.
Although the evaluation of the big quantity of data has just been started first results can be published for the 10 Opel Astra Impuls vehicles. In the first three month the fleet is operating the 10 Opel Astra Impuls have covered a distance of more than 50'000 km, so that a the end of the project mid 1999 a mileage of 400'000 km for the Opel vehicles can be estimated. The six Renault vehicles have covered a distance of 27'000 km until end of June so that for the project a total distance of more than 200'000 km is estimated.
The average daily trip length (Figure 5) depends in most cases directly on the usage (private, commercial, fixed routes ...) of the car. At the moment the car with the lowest average mileage per day is used for 38 km a day, the car with the highest mileage is used for 83 km a day in average. The overall average mileage of the 10 Opel Astra vehicles is 65 km per day. The maximum distance driven per day is nearly 180 km. For the Renault Express THERMIE a maximum range of 202 km (Type 1) and 132 km (Type 2) has been covered.
Figure 5: Average/Maximum dailly trip length (April-July 1997),
Opel Astra Impuls
The state-of-charge at the end of the day is one indicator for the usage of the car. In most cases the battery isn't discharged completely, rather the users leave a reserve capacity of more than 30%. The average SOC at the end of the daily trips is below 50 %, but there is no fear for further discharge, which can be recognized by the minimum SOC (Figure 6).
Figure 6: Average/Minimum state-of-charge at end of daily trips (April-June 1997)
Opel Astra Impuls
First estimations on the operating costs of one user at Aachen (pharmaceutical delivery service, Figure 7) show that through the use of off-peak-power current the operating costs (3.50 DM/100 km) are half in comparison to the before used diesel engine powered vehicle.
Figure 7: Opel Astra Impuls in use at the pharmaceutical delivery company
Since the data collection and evaluation process has just been started further results will be published at EVS-15.
