"An electric drive is less complex than a combustion engine" is often used as an argument in favor of electric cars, as this also reduces the risk of failure and service costs. This is true. However, developers need to take a more differentiated view, at least when looking at the entire powertrain. Here is an overview of the most important tasks - and how to master them.
Due to climate change, drive technology is in the midst of a "turning point": As part of the necessary decarbonization of all economic sectors, CO2 -free alternatives must also be found for fossil-fuelled combustion engines.
These could be engines that run on synthetic fuels or hydrogen. However, the majority of vehicle manufacturers and suppliers are focusing on an electric and sustainable future - be it drives for cars or two-wheelers, commercial vehicles or trucks, agricultural vehicles or construction machinery.
The drive mix currently consists of three main technologies: purely battery-electric drives (BEV), plug-in hybrids with electric and fossil drive (PHEV) and vehicles that obtain their energy from a fuel cell (FCEV), usually based on hydrogen. What they all have in common is that they are essentially based on the electrification of the drive, i.e. that electric motors are (also) installed.
Simple and yet complicated
Electric drives are - rightly - considered to be significantly less complex than combustion engines. This has various advantages: they are easier and cheaper to manufacture, there are fewer potential faults during operation, which means they are less likely to be the cause of workshop visits. And last but not least, there are lower maintenance costs for the vehicle owner, as oil changes and the like are no longer necessary.
If you look at the e-drive in the context of its entire ecosystem, many interfaces in the interaction of different technologies and systems become clear. In addition to the electric drive, the "overall drive system" comprises many more components that are networked with each other and need to be controlled comprehensively. Interrelationships and dependencies contribute to the fact that in some cases even greater complexity can emerge here than with the "fossil" powertrain. 
This is also reflected in the development process. It must not only take into account technical requirements, but also framework and environmental conditions, ranging from the refueling and charging process to sustainability efforts at the end of life. An interdisciplinary development approach is therefore required that reconciles vehicle requirements, operating and disposal strategies and environmental conditions. Increasing digitalization and the integration of the vehicle into this digital living space are not least one of the future drivers of automotive development. The most important development steps are briefly outlined below.
- Concept development
Concept development starts with defining the energy and mechanical requirements of a system. This involves examining how much energy the system requires and how the mechanical implementation should take place in the vehicle. This includes considering the placement of the components (package) and defining the basic functions of the system. Environmental conditions and legal requirements must already be taken into account at this stage. Parallel to the drive concept, the (digital) functions to be implemented and the DNA of the vehicle are defined.
- Feature & function specification and development
The development of features and functions begins once the concept idea and the main functions have been clearly defined. This involves specifying new functions as well as adopting or adapting existing ones. The functions are first specified in detail and then implemented during system development. Here it is particularly important to pay attention to interrelationships and dependencies between the interacting systems. Functional requirements for a system are described by determining which system elements are to be linked with each other in a feature.
- System requirements management
This is where the specific requirements for the drive system are defined and coordinated. This includes not only the technical parameters, but also legal, functional, safety-related and energy requirements. Requirements management serves as the basis for subsequent system development. This must take into account both existing and new requirements, depending on whether it is a further development or a completely new product. Experience has shown that the electrification of the drive tends to go hand in hand with a new development in order to optimize all aspects.
- (Virtual) system development & customization
As part of virtual system development, the system is represented energetically, physically and functionally in a virtual environment. This allows early tests and simulations to be carried out to check the behavior of the system before real prototypes are built. The virtual development is supplemented by real superstructures such as prototypes and so-called mule vehicles. As the vehicle will continue to evolve in the future, even after the SOP (Start Of Production), virtual system development is an important part of the DevOps approach. 
- System integration & system interface management
In this step, the various subsystems are linked together and integrated into the overall system. Interfaces between the systems must be defined and tested to ensure that all components work together smoothly. This requires close coordination between the various functional areas and precise documentation of the interfaces in accordance with standards such as ASPICE. At the same time, new concepts such as the grouping of control systems into zone or central control systems must be taken into account.
- Commissioning & calibration of systems and system functions
Once the components have been installed in a prototype or vehicle, the system is commissioned. This involves calibrating the functions to ensure optimum performance. Here, the properties of the system, such as parameters for functional control, are determined and it is checked whether the desired functions are working properly. In this case too, increased dependencies and interdependencies between different subsystems present developers with new challenges.
- (Virtual) system verification & validation
Verification and validation take place in both the virtual and the real environment. The aim is to confirm the correct implementation of the requirements (verification) and to check whether the system remains functional in practice under various load cases (validation). This process is crucial to ensure the functionality and quality of the system before it is launched on the market.
- Management of cross-divisional functions
Cross-sectional functions concern aspects that affect several systems or subsystems in the vehicle, e.g. the communication architecture or the wiring system design. Interfaces and electrical connections, such as the position of terminals or fuses, are defined here. These functions are central to the interaction of all systems in the vehicle and must be managed across the board.
- Development of the management functions for the energy and drive system (EA)
Energy management is an essential part of the development of the EA management functions. This also includes the operating strategy, shifting strategy, driving strategy and charging strategy. These functions must be developed in detail depending on the drive type and system complexity. Hybrid vehicles, where electric motors have to be coordinated with the combustion drive, are particularly complex.
- Management of EA attributes
The EA attributes include the directly perceptible product characteristics, such as ride comfort and drivability. Examples include the behavior of the vehicle on bumps or the response time to the accelerator pedal. The energy distribution in the vehicle is also defined here to ensure that critical functions are prioritized when the energy status is low. In addition, range and consumption as well as signaling to the driver are managed. In the case of hybrids, emissions also fall under this area. Other aspects such as climate comfort, water management, pollution and the entire aerodynamics through to engine compartment airflow are also included here.
- Component responsibility for e.g. central controls
Component responsibility encompasses the technical and organizational responsibility for certain components, such as central control units. These control units have evolved from individual control units to more powerful central control units that combine several functions. The component manager is the interface to suppliers and internal teams and ensures that the requirements for the control units are implemented and the functions are integrated correctly.
- Development of battery/energy storage systems and drive components as well as control units
The development of core components of the energy and drive system combines hardware and software development, system integration and validation. The end result is components that fulfill their part in the functional chains and contribute to increasing efficiency.
- Technical coordination and integration of HV/H2 safety
The integration of high-voltage (HV) and hydrogen safety (H2 safety) is about ensuring the safety of systems that work with high voltages or hydrogen technology. These safety requirements must be systematically reviewed and integrated into system development in order to ensure safe operation of the drives.
- Technical evaluation of EMC, functional safety and cyber security aspects
Electromagnetic compatibility (EMC), functional safety (FuSi) and cyber security are key technical aspects that must be continuously checked and evaluated during the development process. EMC ensures that electronic systems do not interfere with each other, while functional safety ensures that the system works safely even in fault scenarios. Cyber security is becoming increasingly important in order to protect electronic systems from external attacks.
More support needed
These points illustrate the comprehensive development process of a vehicle powertrain from the concept phase through to final system integration and validation. For vehicles with electric drives, each step is associated with additional requirements and challenges. In addition to electrification, manufacturers also have to cope with digitalization and the increasing proportion of software in vehicles, which also contribute to more connectivity and, as a result, more complexity.
In addition, legal requirements for decarbonization and cybersecurity as well as intense competition for software functions and assistants are placing ever tighter development deadlines on vehicle manufacturers. For many, this means quickly building up and establishing new or missing knowledge and working methods and networking them across domains. However, this often cannot be done to the necessary extent in-house.
Existing gaps can be bridged with suitable partners - ideally those who have been pursuing corresponding developments for a long time and can therefore offer both broad coverage of these topics as well as corresponding project experience. Only those who understand and master the complexity of the entire vehicle can deliver solutions that are efficient in implementation, easy to understand in application and optimal in operation.
One partner that meets these requirements is the EDAG Group with its "Energy Systems and Powertrain" (EA) business unit, which has pooled expertise in all aspects of powertrains and energy systems in order to provide OEMs, start-ups and suppliers with one-stop support from experienced engineers. They offer expertise in all technical issues and also in questions of environmental protection, IT security strategies and legal issues, through to strategies for reuse at the end of the life cycle and the integration of recycled materials and re-use components in production.
Do you need powertrain development services? Then talk to our expert Holger Martin, Head of EA Systems Design, who can give you more details. Or download our white paper "Electrified powertrain: How to master the complex challenges" right here, which describes the higher requirements in the development process in detail and provides information about the support EDAG can provide you with. 
