Electric cars – moving with
energy into a mobile future

Electric motors – proven and perfected many times over

Since the invention of the electric motor about 175 years ago, electric drives have successfully penetrated all sectors of industry. In a battery-powered electric car, the drive generally consists of an electric motor, inverter, battery, and charging device. The interaction of the individual components can be described as follows. The vehicle is propelled directly by the electric motor. For this to happen, the motor must be fed with alternating current, which is supplied by the inverter. The inverter converts the direct current from the battery to alternating current. The inverter also regulates the vehicle’s speed by increasing the rotational speed of the motor as soon as the driver steps on the ‘gas’ pedal.

In contrast to combustion engines, electric drives reach their full torque even at low rotational speeds, enabling prompt forward motion, high acceleration, and thus great driving pleasure. Another key advantage is that electric drives reconvert braking energy back into electrical energy – unlike combustion engines, where the braking energy is lost as heat. During this regenerative process, the motor serves as a generator, similar to a bicycle dynamo. In other words, it works as an electromotive brake while simultaneously feeding energy back into the battery. Electric motors stand out for their high efficiency, meaning they convert the electrical energy nearly completely into kinetic energy.

Advantage of the electric motor

Division of work between a combustion engine and electric motor

To achieve greater distances, people frequently use a combination of a combustion engine and electric motor, called a hybrid drive. Siemens is focusing on the serial hybrid solution for cars and commercial vehicles. Unlike in the parallel hybrid, the electric motor alone provides the drive in the serial hybrid. The combustion engine solely drives an electric generator that charges the battery. With this particular arrangement in the serial hybrid, all the advantages of a vehicle powered purely by electricity are fully exploited. For instance, most notably, the electric motor in serial hybrids is also deliberately used as a brake. The motor then works as a generator, converts the kinetic energy into electrical energy, and feeds this energy back into the battery.

The serial hybrid is especially ideal for city buses and delivery vehicles, which make frequent stops. It is therefore the key element of the Siemens ELFA drive system, which has already proven itself a thousand times over. City buses, which constantly stop and start, consume about one-third less fuel with ELFA. At a total annual distance of 60,000 kilometers, that’s about 10,000 liters of fuel, depending on the route. However, ELFA not only makes the buses more economical, but also quiet, because the revving of diesel engines upon acceleration is eliminated and the diesel engine is operated at a more economical and quieter speed level.

Inventive genius coupled with experience

Since 1879, Siemens has been a pioneer in electric drives and helped electric machines achieve a breakthrough. Even today, systematically converting electricity to movement is still an art. Siemens engineers are making modern motors more powerful, more energy-efficient, and more flexible by integrating all the individual components into a harmonized drive. More than 1.5 million electric motors leave the Siemens production facilities every year. On rails, roads, water, and even in the mountains, Siemens electric drives transport millions of people every day.

Siemens has been a pioneer in electric drives since 1879.

Charging stations in a comprehensive charging infrastructure

A dense network of charging stations is a basic requirement if electric cars and electromobility are to develop further and hold their own. Access to these stations can be public, semi-public (such as at shopping centers), or private. Siemens is developing charging points for various purposes and is also researching further charging possibilities, especially faster charging. The goal is a comprehensive, modular charging infrastructure that makes it possible to charge electric vehicles anywhere – easily and safely.

Explore the possibilities for charging

Public and semi-public charging stations

For charging at public parking lots and in parking garages of shopping centers or companies, Siemens offers the modular charging point Charge CP700A, which can charge electric cars with normal battery capacity within an hour. A display guides the user reliably through the charging process and makes charging as easy as normal fueling. In addition, the modular structure of this charging point makes it possible to tailor the system precisely to the respective needs. It is very easy to use, while also offering a high degree of safety. If a larger number of electric vehicles need to be charged at the same time, the Sitraffic Epos satellite system is the right choice. It combines the functions of charging points and pay-and-display ticket machines. One station can include multiple satellites.

Future solutions for fast charging

Fast DC charging stations are particularly advantageous in places where drivers park for just a short time. For example, drivers can charge their vehicle batteries at these stations while shopping or eating at a restaurant. DC charging systems are therefore the best choice for operators of short-term parking zones and for companies with service vehicles. An alternative to fast charging is the exchange of dead batteries for charged batteries at swapping stations. Since all electrical elements are housed within a closed process or system, the exchange is safe, fast, and convenient – and allows drivers of electric cars to travel long distances without long wait times.

Charging conveniently at home

The Wall Box is designed for charging electric cars in a private environment – such as overnight in one’s own garage. The space-saving device can be installed quickly and easily. Wallbox charging stations are optionally available with communication modules, which allow them to be integrated into a smart grid with its expanded range of services. With all charging options, Siemens generally uses standardized components that protect people and valuable electric vehicles against overloads and short-circuits, while also safeguarding against electric shock in case of contact.

Charging without cables

Inductive charging allows electric vehicles to be charged without a cable and charging point. A completely buried coil, the primary coil, establishes the connection to the public energy grid. When drivers start the charging process, current flows through this primary coil. This creates a magnetic field, which induces electrical current in the secondary coil, which is installed in the vehicle. This induced current charges the electric vehicle’s battery. The charging stations can be integrated virtually invisibly into any environment. The contactless charging process is wear-free and safe from vandalism, making it a convenient option for electric vehicle fleets (such as taxis) or for private homes.

Interaction of all involved elements

Siemens has many years of experience in the areas of electric drives, energy supply, grid infrastructure and IT,, and has for a long time been focusing on the challenge of mobility of the future. The company’s portfolio comprises an extensive range of highly developed and compatible system components and services for electromobility –for the infrastructure as well as for the vehicles themselves. Siemens offers individual solutions, but can also combine all partial solutions into a viable complete solution.

Smart grid and electromobility are essential parts of future developments.

Components for the electric vehicle

In addition to Siemens’ solution packages for drive and control, the efficient LED headlights are one of the vehicle’s components especially worth mentioning. The fully standardized LED automotive lighting JOULE JFL 2 from Osram not only uses extremely little energy, but is also extraordinarily powerful and flexible, and thus ideally suited for use in electric cars.

Components for the charging infrastructure

The infrastructure installations from Siemens cover a wide range of charging scenarios. Proven switching and protection devices, for example, ensure safe processes and automated communication. Quick charging stations, DC charging stations, battery swapping facilities, and the necessary measurement techniques are just as much a part of the offering as grid planning services. The components tailored specifically to electromobility ensure compliance with new standards such as IEC/EN/DIN 61851. All this means that the necessary infrastructure behind the charging stations can be expanded intelligently. Energy management solutions regulate charging operations, the availability of charging stations in the smart grid, and more.

Software solutions for electromobility

Siemens also offers a comprehensive software portfolio which includes infrastructure solutions for energy and fleet management, value-added applications for user guidance and business packages. For example, the software helps record energy consumption data, process payment transactions, and manage security and authorization processes. The software solutions are intercompatible and can be combined flexibly into service packages.

Vision of the “cooperative systems”

Even the interaction between previously separated subsystems in electric vehicles, road infrastructure, and traffic control centers can soon become a reality. Smart software for electric cars can expand the so-called Car2X communication in conjunction with expansion of the communications technology of the electromobility infrastructure. In Car2X communication, cars communicate either with other vehicles (Car2Car) or with the traffic infrastructure (Car2Infrastructure). Car2X turns cars into mobile sensors for traffic control systems. This means that the control system infers the existence and extent of traffic jams from the location and speed of the networked cars. As a result, the system can make better recommendations for detours. And traffic will flow more safely and smoothly, as data on traffic volume, road conditions, or traffic light switching times is exchanged.

The future scenario: cars will communicate with their infrastructure and other cars