Volkswagen e-Golf and e-Up! Electric Cars 2013

Wolfsburg, September 2013. From the middle of October Volkswagen will be supercharging its model range with an extremely efficient electric vehicle – the new e-up!. Creating a double impact on the e-mobility stage, the four-door city specialist will be followed just a few months later, in spring 2014, by a further zero-emissions Volkswagen: the e-Golf. Both electric cars will make their debuts at the International Motor Show (IAA) in Frankfurt (10 th to 22 nd September), heralding the era of full-production e-mobility for Volkswagen. Henceforth Volkswagen will thus be offering in its vehicles every form of drive system relevant in the world today.

e-Golf data. The e-Golf, which is being presented in a world premiere in Frankfurt, is driven by a 85 kW / 115 PS electric motor. The motor produces its maximum drive torque of 270 Nm as soon as it starts off. The results: the front-wheel drive e-Golf reaches 100 km/h in 10.4 seconds.
On a motorway, the speed of the five-seat front-wheel drive car is electronically limited to 140 km/h.
The Volkswagen e-Golf will be on the market several month after the e-up! This article is mostly dedicated to the e-up.

e-up! data. Also making its debut in a world premiere at the IAA is the four-seat e-up!. Its electric motor produces 60 kW / 82 PS. This motor transmits 210 Nm of torque to the driven front axle from a standstill. It completes the sprint to 100 km/h in 12.4 seconds. Top speed: 130 km/h.

Driving ranges tailored for commuters. The e-up! can drive 160 km on one battery charge (18.7 kWh), while the e-Golf with its larger battery (24.2 kWh) has a range of 190 km.

Made in Germany. Innovative drive technologies are core competencies at Volkswagen. Therefore, the e-motors, gearboxes and lithium-ion batteries of the e-up! and e-Golf are developed in-house, and they are manufactured in large Volkswagen component plants in Germany.

Volkswagen e-Up! Presentation

Low ‘fuel costs’. The launch of the e-up! marks the introduction of a next generation electric vehicle that thanks to an armada of innovative detailed solutions uses energy extremely economically. The e-up! consumes, for instance, just 11.7 kWh/100 km. It is thus the efficiency world champion. At an average electricity price of 25.8 cents (Germany, 2013), driving 100 kilometres costs just € 3.02. The e-Golf, positioned two classes higher, attains an excellent value of 12.7 kWh.

Great efficiency. The pioneering efficiency of the e-up! is attributable to the very good cw value for a car of this size of 0.308 (4 per cent lower than the take up!), optimised roll resistance (7 per cent lower), the generally energy-saving drive system components, the highly effective regenerative braking system, innovative equipment modules and a newly developed, particularly efficient airconditioning system.

Innovative engineering. A compact electric motor (60 kW/82 PS), the lithium-ion battery integrated into the floor between the axles and the power electronics form the hub of the new high-tech car’s drive system. The electric motor’s power is transferred to the front wheels via a single-speed gearbox.

Up to 160 kilometres. Delivering 60 kW/82 PS and with a top speed of 130 km/h, the e-up! has a range, dependent on driving style and payload, of between 120 and 160 km; at very low outdoor temperatures the range may lie below these values. This range works especially well in urban areas and for the majority of commuters. In Germany, for example, research by the Federal Ministry of Transport, Building and Urban Development found that around 80 per cent of all car drivers in the country, from commuters to motorists making lots of journeys, drive less than 50 kilometres a day.

Two economy profiles: ‘Eco’ and ‘Eco+’. The range of the e-up! can be varied via three different driving style profiles: the standard mode (automatically on), ‘Eco’ and ‘Eco+’. Anyone nipping around travelling short distances, will stay in standard mode. For drivers wanting to extend the range, the first option is the ‘Eco’ mode. The effects of selecting this mode include paring back the e-vehicle’s maximum power output to 50 kW. In parallel with that the electronics reduce the output of the air-conditioning system and modify the response curve of the accelerator pedal. In ‘Eco+’ mode the electronics limit maximum power output to 40 kW, modify the performance response curve and disable the air conditioning. In the ‘Eco’ and ‘Eco+’ modes the top speed is also reduced.

Regenerative braking in D1, D2, D3 and B. Over and above the driving style modes the range of the e-up! can be influenced via the regenerative braking function. There are no fewer than five levels available: ‘D’ (regeneration only when using the brake), ‘D1’, ‘D2’, ‘D3’ and ‘B’. In an electric car this number of levels leads to a different way of driving. By means of regenerative braking drivers can appreciably slow down the e-up! by lifting their foot off the accelerator. Used in an anticipatory way, regenerative braking thus replaces use of the brake pedal in many situations. At levels ‘D2’, ‘D3’ and ‘B’, the deceleration via regenerative braking is so strong that in this case the brake lights automatically come on. If the battery is fully charged, no regenerative braking occurs.

Great agility. After 4.9 seconds the e-up! is going at a speed of 60 km/h; within 12.4 seconds it’s 100 km/h. In 10.5 seconds it accelerates from 80 to 120 km/h. Top speed is 130 km/h. By way of comparison: the most powerful conventional e-up! (with 55 kW/75 PS) accelerates from 0 to 100 km/h in 13.2 seconds and from 80 to 120 km/h in fourth gear in15.5 seconds. The comparison shows that the e-up! simply blows away prejudiced views about the performance of electric cars and makes a very strong case for itself as the ideal vehicle for inner-city motoring.

Battery in the vehicle floor. The e-up! weighs 1,139 kg. Some 230 kg of that is accounted for by the lithium-ion battery. The fact that this battery lies flat within the floor of the car greatly lowers its centre of gravity and, especially in combination with the high starting torque of 210 newton metres, makes the handling feel extremely agile.

Plugs, wall box and charging stations. To recharge the e-up! you simply connect it to the mains. There are various ways that this is done: the simplest option is to plug the mains charging cable supplied with the car into a conventional 230-volt socket. The battery is then charged from the mains at a power level of 2.3 kW. If completely flat, it is fully recharged in this way within around nine hours. As an option Volkswagen offers via its partners a wall box for the garage or car port thatcharges the battery at a power level of 3.6 kW. The (completely flat) battery would thus be 100 per cent recharged again after six hours. There are also public charging stations that ‘refuel’ electric cars at a power level of 3.6 kW. As a first, the e-up! can also be prepared for the combined charging system (CCS) using a DC power supply. In this case it can be charged via special charging stations at power levels of up to 40 kW. The battery is then 80 per cent recharged after just 30 minutes.

Exclusive features. Volkswagen has developed a range of features and design elements specifically for the e-up! that make the electric car very quickly identifiable as such. The array of bespoke features includes the LED daytime running light’s new signature look, aerodynamically developed alloy wheels and an interior in a bright and friendly design. The standard e-up! equipment also includes applications for the maps + more infotainment/navigation system programmed specifically for e-mobility, a radio/CD system, hands-free phone function, four doors, heated windscreen, air conditioning and heated seats. In Germany the new e-up! will go on sale at a base price of € 26,900 (Germany) – no meagre amount of money for a small car, but a manageable sum for a four-seat, four-door, multifaceted and extremely well appointed high-tech electric car with a highly innovative drive system.

Electric Drive Components in Details

Electric motor and gearbox - 12,000 rpm. The electric motor produces a continuous output of 40 kW/54 PS (2,800 to 12,000 rpm). The maximum output available (also at 2,800 to 12,000 rpm) is, as mentioned above, 60 kW/82 PS. Straight from a standing

Synchronous motor. To be precise the e-up! motor is a permanently excited synchronous motor (PSM) with a single-speed gearbox optimised for minimum friction. The drive unit was developed in close collaboration between the Technical Development Division in Wolfsburg and the development departments of the Volkswagen components factories in Kassel and Hanover. The stator (stationary electromagnet), the permanent magnet rotor and the gearbox are made at the Kassel plant, while the foundry at the Hanover plant provides the complex motor housing fitted with a cooling jacket.

Greater efficiency. During the development process the electric motor’s efficiency was repeatedly optimised via diverse technical enhancements. For the start of full production of the e-up! Volkswagen has thus been able to achieve a level of efficiency that ranks as ‘best in class’. In general the level of efficiency of electric motors is around 90 per cent and thus clearly above that of internal combustion engines. By virtue of the fact that the electric motor and the gearbox have been integrated with very high quality intermeshing inside a single housing unit, the drive system is also particularly quiet and compact. The gearbox itself has, as mentioned, a single fixed forwards gear. To go into reverse, the electric motor’s polarity simply gets switched around. In other words, the motor revolves in the opposite direction. The driver selects, as usual, modes ‘D’ or ‘R’ and, of course, ‘N’ (neutral) or ‘P’ (park).
Further components contained in the gearbox include, in addition to the differential, the motor shaft, which revolves at very high speed (12,000 rpm), and the mechanical parking brake, constructed in extraordinarily lightweight fashion.

Lithium-ion battery - 204 cells in 17 modules. The lithium-ion battery fitted in the e-up! weighs 230 kg and is made up of 17 modules, each with 12 cells. These 204 cells add up to a rated voltage of 374 V and rated power of 18.7 kWh. At peak level the cells provide an effective power output of 75 kW and over a continual period 35 kW. The battery, which is 1,726 mm long, 1,132 mm wide and at its highest point 303 mm
high, has been integrated, as already indicated, in space-saving fashion within the floor of the e-up!.
Compared to other lithium-ion cells (e.g. from the field of consumer electronics), the battery system’s cells are particularly resistant to heat and cold, meaning that no separate battery cooling or heating is required. Like the electric motor and the gearbox, the battery system, battery electronics and the relevant control software were also developed in house at Volkswagen.

Power electronics - Energy flow interface. Another central element of the drive system is what is known as the power electronics. This complex module weighs 10.5 kg in the e-up! and, acting as the link, controls the flow of high-voltage power between the e-motor and the lithium-ion battery (depending on battery voltage between 296 and up to 418 V). In doing so the power electronics convert the direct current (DC) stored
in the battery into alternating current (AC) and use this to drive the motor. Via a DC/AC converter it also supplies the vehicle power circuit with a voltage of 12 V. The modules of the power electronics (LE 2.3) used in the e-up! include the motor inverter control circuit board, the DC/DC converter, a DC link capacitor and a controller board.

Phase and traction cables. The power electronics module is connected to the e-motor via the sort of yellow-and-orange three-phase cable typical for electric vehicles. The connection to the lithium-ion battery is established via two traction cables.

Direct current becomes alternating current. In respect of the all-controlling power electronics a distinction has to be made between two fundamentally different modes in which the e-motor operates: motor mode (propulsion) and generator mode (regenerative braking). In motor mode the power electronics use high-power transistors to convert the direct current (DC) stored in the battery into threephase alternating current (AC). In generator mode, meanwhile, the alternating current is rectified for charging the battery. In this scenario the power electronics are like a kind of valve that let the electrical current flow only towards the battery that is to be recharged. This maximum phase current of the power electronics is limited in the e-up! to 385 A.

High voltage becomes vehicle power circuit voltage. As mentioned above, the 2.5-kW DC/DC converter integrated into the power electronics is responsible for supplying the vehicle’s 12-V power circuit and thus works like a transformer. The 12-V power circuit and the high-voltage circuit are completely separate from each other in the vehicle. Also included in the power electronics are the controller for running the management software and a CAN interface for communication with control
devices. Last but not least, the power electronics module dampens the effects of any sudden loading of the drive system (for instance, at moments of sudden acceleration) by regulating the torque accordingly.

Electromechanical brake servo - A combination of brake system and motor brake. Electric cars are essentially equipped with two brake systems independent of each other: on the one hand, as in conventional cars, a mechanical, hydraulically operated brake system is there to slow the car down. At the same time, however, the e-motor acts when recovering energy as a motor brake. These two types of braking now blend together in the e-up! thanks to the electromechanical brake servo.

The brake servo’s task. Regardless of regeneration mode (‘D1’, ‘D2’, ‘D3’ or ‘B’), when operating as a generator the electric motor generates a degree of braking torque on the wheels – dependent on its speed and the battery’s temperature and charge level. The variable parameters – motor speed and battery status – lead to fluctuating levels of electric braking. These fluctuations need to be hydraulically compensated and the degree of deceleration matched in this way to the braking performance called for by the driver. The management of the brake system required for this is called brake blending and is achieved via the new electromechanical brake servo. Volkswagen has succeeded here in its primary aim of making maximum utilisation of the e-motor’s potential to slow down the e-up! in order to increase its range.

Less wear on the brakes. As the majority of braking processes involve only minor or moderate deceleration and are therefore executed without any wear via the e- motor, the electric system helps to keep the ‘normal’ brakes in top condition longer.

Production location: › Vehicle – Bratislava plant (Slovakia); powertrain – Kassel and Hanover plants; high-voltage battery – Braunschweig plant.

Eight years / 160,000 km guarantee on the battery - Owners of the e-up! get a guarantee on the car’s high-voltage battery for eight years or 160,000 kilometres. Alongside that the existing Volkswagen warranty/guarantee period of two years with no kilometre limit applies for all faults covered by the warranty. For paintwork defects an extended
guarantee period of three years applies, while the anti-perforation guarantee is for 12 years.