How does an electric car work?

4 min read

An electric car is powered by one or more electric motors that convert electrical energy from batteries into motion. Compared to internal combustion engines, they operate efficiently, with little wear and tear and are largely noiseless [1]. The propulsion energy comes from rechargeable batteries, usually lithium-ion cells. An inverter converts the direct current from the battery into alternating current for the motor. During braking or when driving downhill, energy can be recovered through recuperation. Typically, a single-speed transmission is sufficient, often with front-wheel drive [1].

The Main Components of an Electric Car

The central components are the battery as the energy storage, the electric motor, the power electronics, and the charging system. The battery, usually a lithium-ion battery located in the vehicle floor, stores electrical energy in kilowatt-hours (kWh). The electric motor converts this energy into mechanical motion and provides full torque immediately with high efficiency [1].

The inverter or power electronics convert direct current (DC) from the battery into alternating current (AC) and control the speed and power. The charging port and the onboard charger enable charging by converting alternating current from the grid into direct current for the battery [4].

Differences from the Internal Combustion Engine

Unlike the internal combustion engine, which converts chemical energy into mechanical energy through combustion, the electric motor converts electrical energy directly. The electric motor has only a few moving parts, such as the rotor and stator, while internal combustion engines require pistons, a crankshaft, and many other components [1]. The stator generates a uniform magnetic field, and the rotor creates an alternating magnetic field through alternating current [3].

Electric motors achieve high efficiencies of over 90 percent and deliver maximum torque from the first revolution, making a multi-speed transmission unnecessary. Furthermore, recuperation allows for the recovery of energy, which is not possible with internal combustion engines [1].

Processes in the Battery During Charging and Driving

During charging, current flows into the battery, whereby lithium ions move through the electrolyte from the cathode to the anode (usually graphite) and are stored there—a process called intercalation. During driving, this is reversed: the ions migrate back, which generates a flow of electrons that powers the motor. Lithium-ion cells enable high voltages of approximately 3.6 to 3.7 volts per cell and high energy densities without a memory effect [2].

Recuperation and Its Contribution to Range

Recuperation refers to the recovery of kinetic energy during braking or deceleration. The motor then acts as a generator and converts kinetic energy into electrical current, which charges the battery. In city traffic, this can significantly increase efficiency, as frequent braking recovers energy that would otherwise be lost as heat [1]. The intensity is often adjustable, extending to one-pedal driving.

Factors of Actual Range

The range depends on temperature, driving profile, speed, and payload. In winter or at high highway speeds, it decreases noticeably due to higher consumption for heating, cooling, or air resistance. Studies show that recuperation is particularly helpful in city traffic, while constant high speeds minimize the effect [5].

Charging with Alternating Current and Direct Current

During alternating current (AC) charging via a socket or wallbox, the on-board charger in the car converts AC to DC – typically with 11 or 22 kW, resulting in charging times of several hours. With direct current (DC) fast charging, the conversion takes place in the charging station, allowing high power up to 350 kW to flow directly into the battery and charge in minutes. AC is gentle for everyday use, while DC is faster for long distances but puts more strain on the battery [6].

Ecological Balance Considering Battery Production and Power Mix

The production of the battery causes a CO₂ backpack due to raw material extraction and energy-intensive manufacturing. However, with the German power mix, this amortizes after several tens of thousands of kilometers, as operation is lower in emissions than with internal combustion engines. The advantage grows with the increasing share of renewable energies. Recycling and second-life use further improve the balance [5].

Battery Lifespan and Recycling

In practice, lithium-ion batteries often last well over 200,000 km before the capacity falls below 70–80 percent. Manufacturers usually guarantee eight years or 160,000 km. Afterwards, many are suitable for a second life as stationary storage. At the end, recycling takes place, where over 90 percent of metals such as cobalt, nickel, and lithium can be recovered. Modern processes such as hydrometallurgy increase efficiency, and legal quotas promote the use of recycled materials [1].

Persistent Disadvantages and Open Questions

Despite progress, challenges remain such as charging infrastructure, range anxiety during cold weather or high speeds, higher acquisition costs, and raw material dependencies. The power grid must be expanded, and social aspects such as access for tenants without charging options remain open. Technically, production-ready solid-state batteries for even higher densities and faster charging times are still missing. Nevertheless, the technology offers clear advantages in efficiency and emissions [1].

In summary, the direct and efficient energy conversion of an electric car is convincing. With the ongoing development of batteries, infrastructure, and recycling, it is becoming an increasingly sustainable mobility solution.