Development and validation services for electric vehicles

At Bertrandt comprehensive solutions relating to all aspects of electromobility are taking centre stage. These include the electric powertrain and the development of high-voltage batteries and functions and applications for the power electronics. Related interdisciplinary areas of expertise, such as multi-voltage electrical systems, lightweight design, component integration, operating strategies and driving dynamics, also play an important role.

Our solutions for electric vehicles are complemented by our experience of the charging infrastructure, including charging technologies and integration into smart grids. Our development services for electric cars cover the entire spectrum of requirements from components and systems to complete vehicle concepts. Bertrandt has its own in-house electromobility centres. This enables us to turn development concepts into reality and to take responsibility for testing and validation. We work for all the well-known vehicle manufacturers and automotive industry suppliers and also for carmakers that are just starting out on the process of developing new electric vehicle platforms.

Bertrandt is working on internal and customer projects for the automotive industry which involve developing the charging infrastructure for electric vehicles. We cover the entire process of establishing a non-proprietary charging infrastructure. This includes:

  • Global charging standards
  • Inductive (wireless) charging technologies
  • Conductive (wired) charging at charging stations
  • Compatibility of AC/DC charging processes
  • Data connections and charging protocols
  • Safety and security when charging
  • Integrating charging stations into a smart grid

Inductive charging project 
One example of our work is an inductive charging project for a first-tier supplier. We have jointly developed a system for inductive charging and subjected it to thorough testing. In this wireless solution, the battery is charged by means of induction from a coil in the ground to a coil under the vehicle. We have investigated the effectiveness of the energy transfer, the position of the vehicle on the charging panel and the safety measures needed during the charging process.

Communication during charging
One aspect of our development work involves the communication between the vehicle and the charging infrastructure. We develop electronics systems and software for (wireless) data communication to determine the current charging status, authorise the start of the charging process and manage charging protocols, including identification, monitoring and connections to higher level systems.

Charging stations in the smart grid
Another important consideration is the integration of charging stations into smart grids. Bertrandt has the necessary expertise to carry out methodical analyses of energy consumption and to apply the laws of the electricity balancing market to energy requirements analyses in order to introduce strategic and technological improvements.

We offer comprehensive services for the development of high-voltage battery variants which start with the concept of how primary batteries can be transferred into newly developed vehicles and derivatives and also include mechanical, electric and thermal design and testing.

Battery design and thermal management
In addition to the storage capacity, the design and development of batteries also involves determining their shape and the way that they are integrated into the vehicle structure. However, the available installation space is not the only important consideration when developing a battery package. Other issues include the performance requirements, the resulting design and the number of individual battery cells. The ideal arrangement, the composition of the cell packs and the provision of additional space for cooling systems and control units also have to be taken into account. Crash safety also plays a key role, together with the thermal design of the system. We use virtual development methods and simulation to identify the type of cooling system required.

Electrical connections
Battery cell modules are connected together electrically via busbars. We develop the electric circuit for the cell modules to meet the performance requirements. We also fine-tune connection systems, make the connections more robust and identify how to provide the largest possible capacity.

Bertrandt integrates sensors and electronic systems that monitor the temperature and voltage and transfer data to the battery management system (BMS).

Battery management systems 
Bertrandt develops software algorithms for battery management systems (BMS). Using the temperature and voltage data we have collected, we ensure that the cells remain within the ideal operating range, by achieving the best possible cell balance and improving the charging strategies.

Modern vehicle architectures make it possible for us to transfer BMS data to higher level vehicle systems. Connectivity and back-end systems enable data to be sent to cloud solutions such as the Bertrandt Automotive Cloud. This allows vehicle owners to see the battery status and manage the charging process via mobile devices and smartphone apps.

Test centres for high-voltage batteries
Bertrandt has several in-house test centres where all aspects of the electric powertrain and batteries in particular can be assessed and validated. We test a variety of mechanical and electrical features in accordance with the latest standards and have the flexibility to design test processes to meet customers’ requirements. We provide a selection of multi-channel test systems with power categories up to 1000 V/1000 A. Our comprehensive safety features ensure that these systems operate safely.

We can build prototype batteries in our own high-voltage workshops. In addition, high-voltage batteries can be tested under extreme climatic conditions and loads in climate test chambers (using multi-axis shaker tables). We can also dismantle batteries for analysis purposes after testing has been completed or when the batteries have been returned from use in the field.

We are continuously increasing the scope and performance of our high-voltage testing resources. Highly trained engineers and battery specialists ensure that the tests produce high-quality results.

Other aspects of the process of developing variants of high-voltage batteries

  • Energy storage concepts
  • Complete development of battery variants
  • Testing and analysis of batteries in high-voltage testing centres

The powertrains and, in particular, the high-voltage systems of electric and autonomous cars, which consist of batteries, inverters and power electronics, are giving rise to new energy, performance and availability requirements.

Power supplies of 300 kW or more are needed, which requires the use of high-power inverters with voltage levels of 400 to 1000 volts. Bertrandt is developing software applications that can be integrated into vehicle systems with different power categories for the purpose of reducing power losses and improving efficiency. Our systems take into consideration the increased functional safety requirements.

Our test centres are equipped with extensive facilities for testing and validating the mechanical and electrical functions of high-voltage components such as inverters.

Designing a robust electric drive system requires a multi-disciplinary approach, in particular in the case of hybrid concepts. We are able to combine our extensive experience of developing conventional and hybrid powertrains  with our electronics expertise.

The electrical/electronic architecture of electric cars is undergoing fundamental changes, which are leading to the introduction of new control and operating strategies. This in turn has an impact on the design of vehicle wiring systems. Multi-voltage systems and the accompanying safety features, connection methods and ideal (distributed) wiring system architecture are key aspects of the development process.  Other important considerations include the available installation space, fault resistance and improved wiring routes.

Bertrandt is working on a variety of projects relating to the development of the electric powertrain. As well as designing hybrid and electric powertrains, developing operating strategies and adapting them to different applications, we can carry out comprehensive functional tests in our well-equipped test centres.

Bertrandt develops test concepts and has extensive testing facilities for electric motors and electric drives (two-wheel and four-wheel drive test rigs). Key features include

  • Test centre for power electronics
  • Electric drive test rigs (two-wheel and four-wheel drive)
  • Test concepts for electric powertrain components
  • Designing electric drive systems

More about eMobility Testing

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Thomas von Harten

Vice President Operations – eMobility Systems

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