The electric vehicle (EV) represents the frontier of sustainable mobility. EVs integrate a complex and sophisticated electronic architecture, and technology is taking giant strides every day with the discovery of new semiconductor materials and solutions. In this article, the most important components and their interconnections that enable the operation of electric vehicles will be explored.
Introduction
The adoption of electric vehicles is steadily evolving, and all sectors of the supply chain are changing as well. It covers raw materials, chemicals used to make electric vehicle parts, batteries, and various components. At the same time, vehicle charging infrastructures are also involved, which are going through a historic phase with a radical redesign. Their electrification, together with government regulations, challenges the design of new automotive networks and software development. Electronic systems architecture is the structured configuration of all electronic components, modules, and networks within a vehicle and defines its electrical and electronic composition. In particular, the electronic hardware, the network communications system, the software, and the wiring of all the circuits are integrated to enhance control over the functionality of the vehicle in all its facets.
An electric vehicle is not solely a means of transport with an electrified engine; rather, it is equipped with highly sophisticated peripherals along with refined electronics, which enable the implementation of several types of applications. An electric vehicle is a complex system of technologies that bases its operation on physical, chemical, electrical, and electronic bases. It is equipped with an autonomous power supply battery and there are various circuits dedicated to carrying out different functions. A good architecture must consider the power and information requirements of all electrical devices operating in the vehicle. If the purely mechanical aspect is approximately similar to that of traditional internal combustion vehicles, such as the wheels or the frame, the electrical part is quite distant, containing substantial and freshly designed differences. They concern the battery system used for traction, the electric motor, the power regulation circuits, and those dedicated to battery charging. As can be seen in Figure 1, an elementary configuration of an electric vehicle consists of one or more batteries, an energy converter, an electric motor, a transmission component, and the differential system that controls the wheels.
There are more effective systems, without the differential, which involve propulsion through two motors, one for each drive wheel. In this case, two separate and independent conversion systems are required, though there can only be a single battery power supply. With the technological advancements of recent times, new architectures have improved the efficiency and connectivity of systems, also integrating communication protocols such as CAN, LIN, FlexRay, and Ethernet. Today, with the increased use of electronic components in vehicles, a well-designed architecture is necessary to promote reliability and safety while driving, as well as improve efficiency as a result of a reduction in energy consumption, weight, and costs (see Figure 2). Thanks to improved connectivity strategies and the use of fast local gateways, new electric vehicles are configurable and intelligent. Currently, it is possible to set up new applications, previously unthinkable, thanks to the availability of new, extremely sophisticated integrated circuits and electronic solutions made possible only by new electronic components.
Electrically powered vehicles are not all equivalent; rather, they follow different types of design. The key feature, however, involves a percentage of electrical energy assigned to propulsion. Some vehicles merely use electricity for motion, and others that use it in conjunction with other forms of energy, defined as “hybrid”. Broadly speaking, the former utilizes propulsive energy supplied entirely by an electrical source such as a battery or a fuel cell. The latter uses various propulsive energy sources, at least one of which is electric. The design of electric vehicles is predominantly aimed at their autonomy, maximizing speed and acceleration. As can be seen from the previous figure, an electric traction system is made up of various functional blocks: the electric motor working together with the power converter, connected via wiring. The circuit is connected to an energy storage system assisted by a charging system from an external source. Traction is controlled by several devices. Naturally, there are auxiliary liquid cooling systems necessary to maintain the system at a safe thermal level.
The battery and the BMS
One of the fundamental components of an EV is the battery which, in conjunction with performance optimization circuits, constitutes the vehicle’s propellant. The battery stores electrical energy that powers the engine and all other components of the vehicle. Currently, lithium-ion batteries are the dominant technology, offering a positive balance between energy density, durability, and weight. With such powers at play, it is necessary to implement sophisticated safety systems, providing protection from extreme thermal conditions, topping up electrolytes, for the inevitable fuses, ventilation for gas leaks, and charge balancing as, during charging and discharging, the individual elements of a battery tend to have different electrical potentials, resulting in imbalance issues. The components are managed by a control and supervision system, the BMS (Battery Management System), which regulates the charging and discharging commands, and thermal and power control, ever guaranteeing maximum efficiency.
It can be said that the BMS serves as the brain of the electric vehicle, constantly monitoring all electronic systems, battery, engine, power, and auxiliary devices, ensuring the safe and optimal operation of the vehicle. Figure 3 shows a 48 V 2.4 kWh lithium battery from PYLONTECH along with an inverter. It requires the presence of a BMS for its correct functioning. The wiring between the electronic components must also be carefully designed. The vast power levels involved imply meticulous planning, especially on the cable sections which certainly affect the weight and dimensions of the system. Long-term sales estimates for new electric vehicles are promising, with an expected growth of a few dozen percent in the coming years, as the entire sector aims to drastically reduce carbon across all activities.
The electric motor
The electric motor (see Figure 4) converts electrical energy into mechanical energy, moving the vehicle’s wheels. There are different types, such as asynchronous induction motors and permanent magnet motors, each with its strengths and weaknesses. The choice of the engine depends on various factors such as performance, efficiency, and costs. In an electric car, the motor is generally located near the wheels and is powered by a bank of rechargeable batteries. When the accelerator pedal is pressed, the electric motor draws energy from the battery pack and transmits motion to the wheels. It is characterized by instant and constant driving torque, for very smooth and silent acceleration. Normally, the electric motor consists of a rotor, the rotating part, and a stator, the fixed part.
At the heart of electric motors, there is power electronics, which plays a crucial role in energy management. It converts the battery voltage to levels suitable for the engine via DC-DC and DC-AC devices. The latest research is aimed at recovering energy from physical events such as the recovery of braking energy. During braking, kinetic energy is converted into electrical energy, which is then stored in the battery. This process slightly increases the vehicle’s range. All the components of an electric vehicle do not operate in isolation but continuously communicate and exchange data and information through communication networks. This new concept allows for real-time data exchange on the status of the system, activation of intelligent control strategies on all parts of the vehicle, and coordination of the collective operation of the different components.
Conclusion
The first thing you notice in an electric vehicle is the silence of the system, which not only contributes to reducing air pollution levels but noise pollution as well. The architecture of the electronic systems in an electric vehicle is certainly a much complex sector as there are many components at play. It primarily focuses on the need to minimize environmental impact as much as possible, taking into account the entire supply chain, from the production of raw materials to user battery charging. The electronic systems in EVs are constantly evolving, and related innovations will also concern autonomous driving and driving assistance, aided by artificial intelligence for greater safety and comfort. The flawless design of excellent architecture is essential for the development and future evolution of this revolutionary technology.
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