What is an Electric Vehicle (EV)?--Brief Description of the Automobile History from the Birth to Electrification

2-1. Birth of the automobile (internal combustion engine)

The automobile was invented as a means by which people could travel faster, farther, and more comfortably than traveling on foot or by horse-drawn carriages. The automobile has an engine that burns gas to create torque, and through this torque, power is transmitted to the wheels to run the automobile.

The engine works as follows. Rotation of the crankshaft moves the piston downward, allowing the petroleum fuel and air (fuel-air mixture) to come into the cylinder. Subsequently, the crankshaft rotates again to move the piston upward, which compresses the fuel-air mixture in the cylinder. At this point, the ignition plugs ignite the fuel-air mixture, causing it to explode/expand and push the piston down. This motion from the piston is transmitted to the crankshaft, which transforms the piston’s linear motion into a rotational motion. In the past, the initial process of rotating the crankshaft was done manually by the driver. Modern vehicles, however, are equipped with electric starters that start vehicles with no human labor whatsoever. Once the engine starts, its rotation puts the fuel supply equipment into action, thus allowing the engine to keep running. Specifically, the rotation of the crankshaft activates the timing belt, which controls the opening/closing of valves that adjust supply of the fuel and air.

2-2. Electrification of in-vehicle equipment (trend toward electrification of automobiles)

For many years, the automobile has been relying on the engine’s rotational driving force. In recent years, however, "electrification" has been progressing, producing a series of automobiles not relying on just the engine’s power only but also using electric power from motors, etc., as well. Electrification offers various advantages, including the major advantages described below.

Improved comfortability and convenience
Automobiles from the old days have the following disadvantages. When starting the engine, the driver feels annoying vibrations or hears noise from the vehicle’s body. In addition, the steering wheel was heavy for the driver to turn, and the air conditioner, lighting instruments, and car windows were slow to operate due to poor battery performance. In contrast, a modern vehicle is equipped with a high-performance battery and an electronic control unit that are combined to offer various advantages: a push button starts the engine without any noise; the air conditioner is automatically set to a specified temperature in accordance with an ambient temperature; the power steering wheel is light for the driver to turn; and the car windows open/close smoothly. These advantages greatly improve the comfortability of the driver in the vehicle. The modern vehicle has also solved the problem of an engine’s failing to start in freezing conditions, thus offering an environment where anyone can enjoy driving without any stress.

Improved traveling performance
In the past, the vehicle was controlled by and large mechanically, and therefore improving its response by stepping on the accelerator pedal or its fuel efficiency was limited. An electric control unit (ECU) incorporated in vehicles today constantly monitors the combustion state of the engine and allows the fuel to be supplied at the best possible timing. It causes the vehicle to respond accurately to an acceleration action, suppresses unnecessary fuel consumption, and widely improves acceleration performance. Its integrated control over braking, steering, etc., allows the vehicle to run in a more stable manner.

Improved safety
When driving using a conventional vehicle, drivers has to rely on nothing but their eyes, and their agile response to cope with a blind spot or an unexpected dangerous situation is limited. The advanced driver assistance system (ADAS), one of the state-of-the-art technologies, includes multiple sensor elements, such as cameras, radar, and LiDAR, that constantly monitor the surroundings of the vehicle. Upon detecting a hazardous situation, the system actuates the brake automatically or prevents the vehicle from veering out of the lane where the vehicle is driving. Its safety function works far quicker than human reaction can, thus ensuring safety. This widely reduces the risk of an accident and provides an environment where people can drive safely.

Environmental friendliness (CO₂ reduction)
Every conventional gasoline-fueled vehicle emits a lot of carbon dioxide or hazardous gas when traveling. It is a vehicle that produces a high environmental impact. In contrast, a hybrid vehicle or an electric vehicle (EV) creates far less environmental impact, thanks to the latest lithium-ion battery and electric system it carries. Particularly, the regenerative braking system incorporated in such vehicles recovers the energy created by braking and reuses the recovered energy in the form of electricity, thus making a great contribution to a reduction in fuel consumption and CO₂ emission. In addition to this, charging the battery with renewable energy, such as solar energy, gives us great hope for the realization of more environment-friendly mobility.

In this manner, the electrification drive in recent years aims not only to provide an auxiliary means or substitute for the engine, but also to turn various pieces of equipment that used to be operated manually into power-operated equipment. This process allows us to realize a mobile space where people drive vehicles more comfortably and safely.

2-3.Expanding xEV share and its background

xEV is a collective reference to electric vehicles. It stands for electric vehicles of various types involving different technologies for electrification, such as the battery electric vehicle (BEV), hybrid electric vehicle (HEV), plug-in hybrid electric vehicle (PHEV), and fuel cell electric vehicle (FCEV). Following the recent trend of electrification, manufacturers are putting a series of new xEVs on the market under the background of intensifying environmental regulations and rising consumer awareness.
This has led to an expectation that the market share of internal combustion engine (ICE) vehicles will drop, as xEV becomes the major trend in the market. The next chapter will discuss the types and characteristics of xEVs in detail.

3-1. Types of EVs

While an ICE vehicle runs on gas, an xEV runs on electricity. xEVs are roughly classified into "battery electric vehicles (BEVs)" and "hybrid electric vehicles (HEVs)," with HEVs being further classified into subcategories according to their charging methods and degree of electrification.

The BEV uses a battery for traveling, such as a lithium-ion battery, as the energy source, and travels by consuming the driving force from an electric motor. The HEV, on the other hand, combines an electric motor and a gasoline engine to give the vehicle its driving force. HEVs are further classified into subcategories according to their battery charging methods and degrees in which the engine is involved in the process of providing the driving force.

• Degree of electrification (difference in the role between the engine and the motor)
  Strong hybrid (SHEV)
  A strong hybrid type travels using both the engine and the motor. When necessary, it can travel using the motor only.
  Mild hybrid (MHEV)
  The mild hybrid type mainly uses the engine to travel. Its motor merely plays an auxiliary role in providing a driving force. This type of vehicle, therefore, cannot travel using the motor only.
• Differences in charging method
  Plug-in hybrid (PHEV)
  The plug-in hybrid type is rechargeable. It can travel a certain distance relying on the motor only.
  Range extender electric vehicle (REEV)
  REEV is, basically, driven with the motor only. Its engine is used to run the motor to generate power.

3-2. Market trend (trend toward xEV, i.e., electrification of automobiles)

In the automobile industry, the growing trend of electrification continues, and expanding sales of xEVs is a primary factor of the market growth. It is expected that only 25% of vehicles will be conventional ICE vehicles by the year 2030 and that a growth in global vehicle production in the future will be led by BEVs.

Currently, the standard voltage of batteries used in xEVs is 400 V, while recently, batteries with a high charging voltage like 800 V or 1000 V have come onto the market. A higher charging voltage allows for a shorter charging time, higher power output, and a lighter battery weight. However, providing such high-voltage batteries involves challenges to tackle, such as higher manufacturing costs and a charging infrastructure to build. For this reason, batteries with a charging voltage of 800 V or higher are adopted for high-performance EVs, such as luxury cars and sports cars, and batteries with a charging voltage of 400 V are expected to remain the mainstream of the entire market.

3-3. Changing specifications required for electrification

In-vehicle electrical equipment is powered by different types of batteries, depending on its application and power requirements. Batteries that feed these pieces of equipment are roughly classified into two categories: "low-voltage batteries" and "high-voltage batteries."
A 12 V lead battery is used to power equipment operating at low voltage. This battery is used as a power supply for various pieces of electrical equipment that make up an automobile, supplying power to cameras, the navigation system, lighting instruments, the air conditioning system, the electronic control unit, etc. This type of battery, which is incorporated in engine-powered vehicles and in electric vehicles as well, is capable of stable power supply to electrical equipment.
An example of a battery that feeds equipment operating at high voltage, on the other hand, is a lithium-ion battery with a charging voltage ranging from 400 V to 800 V. Equipment like a main motor and an inverter needs high power for producing a strong driving force (torque) and achieving high-speed rotation. In such cases, a high-voltage battery can supply the necessary power with a smaller current flow. As a result, the motor and inverter are run efficiently while their energy losses are suppressed. The high-voltage battery is used exclusively for a specific piece of equipment, such as the main motor that needs a voltage of several hundred volts.

Specifications of the high-voltage battery vary, depending on the type of vehicle and use of the battery. The battery requires a different "voltage" and "capacity" for different types of vehicles. A BEV whose primary power source is the main unit motor needs a high-voltage/large-capacity battery with a charging voltage ranging from 400 V to 800 V and a capacity ranging from 30 kWh to 150 kWh. A MHEV whose primary power source is the engine, on the other hand, carries a relatively small battery with a charging voltage of 48 V and a capacity ranging from 0.5 kWh to 1.0 kWh.
To offer advantages such as "longer driving range," "shorter charging time," and "lighter battery weight," the technical progress to achieve a battery with a higher voltage and a larger capacity will be in demand in the future.

4. Conclusion

5. Related information

• What is a Telematics Control Unit (TCU)? - Equipment configuration and key points for achieving higher performance -
• What is a Domain Control Unit (DCU) used in autonomous driving technology?- Group of devices that contribute to higher performance -
• What cameras are installed in ADAS and AD systems?- Groups of devices that contribute to the enhanced performance of equipment -
• What Is LiDAR in Autonomous Driving Technology?- Points to Consider in Achieving High-Performance Sensing Function -
• What Is Radar Used for in the ADAS and AD System?– Support Autonomous Driving by Using Radio Waves –
• What Is an On-Board Charger (OBC) Incorporated in Electric Vehicles?– AC/DC Conversion System That Allows Faster Battery Charging and is Highly Efficient –
• What Is a DC/DC converter in an Electric Vehicle (EV)?- Device that converts high voltage into low voltage -
• What Is BMS in an Electric Vehicle (EV)?- System that monitors and controls battery state and performance -
• What Is a VCU That Monitors and Controls Vehicle?- Core unit that controls various pieces of equipment, based on external signals -
• What Is EPS?- System that assists driver in operating the steering wheel with power from motor -
• What Is ESC?- Technology for Preventing the Skid of a Vehicle to Improve Driving Safety -
• What Is the Cooling System Pump?- Circulate Water to Curb Heating of Equipment -

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