Electric vehicles seem to have “no engine”, but the core still has “three major parts” – motor, battery, and electronic control. These three components determine the power, endurance and control of electric vehicles. Today, I will use the most straightforward language to help you understand them all at once.
1. Motor: The “heart” of electric vehicles
Function: Convert the battery’s electrical energy into power to drive the wheels. Core indicators: power (unit kW, determines the acceleration speed), torque (unit N·m, determines the starting explosive power), and maximum speed (affects the top speed).
Classification:
1. Permanent magnet synchronous motor by working principle
Features: high efficiency (over 90%), small size, low noise, commonly used in family cars (such as BYD and Weilai).
Advantages: abundant torque at low speed, suitable for frequent start-stop in cities.
Asynchronous induction motor
Features: good high-speed performance, but slightly higher energy consumption (such as the early Tesla Model S).
Advantages: simple and durable structure, suitable for models that pursue top speed.
2. By driving mode
Single motor (RWD/FWD): low cost, long battery life (such as Tesla Model 3 RWD).
Dual motor (four-wheel drive): strong power, fast acceleration (such as BYD Han EV four-wheel drive, 0-100km/h in only 3.9 seconds).
In a word: the motor is like the “muscle” of an electric car, the permanent magnet synchronous motor is an “endurance player”, the asynchronous induction motor is a “speed player”, and the dual motor is a “muscle man”.
2. Battery: The “blood” & safety core of electric vehicles
Function: Store electrical energy, determine the range and charging speed, and are more directly related to vehicle safety.
Core indicators: In addition to capacity and energy density, thermal runaway temperature, flame retardant design, and battery management system (BMS) are the key to safety.
Classification and safety differences
1. By chemical type (safety is the core watershed)
Ternary lithium battery (nickel-cobalt-manganese)
Advantages: good low-temperature performance (can still run at -20℃), but the thermal runaway temperature is low (about 200-250℃). Once a fire breaks out and the combustion is intense, professional firefighting is required. Improvement direction: Improve safety through ceramic coating diaphragm (to prevent puncture short circuit) and flame retardant electrolyte (to reduce the combustion speed) (such as CATL’s ternary lithium technology). Applicable scenarios: high-end cars/northern models need to be equipped with efficient thermal management systems (such as Weilai’s BMS to monitor the battery cell temperature in real time).
Lithium iron phosphate battery (LFP)
Innate advantages: The thermal runaway temperature is as high as 500℃ or above, and it does not catch fire or explode in the needle puncture test. It is called the “fire extinguisher in the battery industry”. Representative technology: BYD’s “blade battery” increases structural strength by arranging rectangular cells, and it is not easy to short-circuit even if it is squeezed and deformed; Tesla’s 4680 battery adopts a pole-free ear design to reduce internal heating points. Applicable scenarios: First choice for family cars, especially in hot areas in the south. With CTP module-free technology, the range can reach 600km+ (such as BYD Han EV).
2. By packaging method (affecting collision safety)
Traditional module battery: The battery pack is composed of independent modules. There is a buffer space between modules during collision, and the maintenance and replacement cost is low, but the overall strength is weak (such as the early BYD e series).
CTP/CTC battery: The battery and the body are integrated into the design (such as Tesla Model Y), and the body rigidity is increased by 20%+, but once the bottom support is punctured, it may cause the entire pack to be scrapped or chain thermal runaway.
“Triple Line of Defense” for Battery Safety
1. Material safety: Use high temperature resistant electrode materials (such as lithium iron phosphate positive electrode) and insulating coated wires to reduce the risk of short circuit from the source.
2. Structural safety: The battery shell is made of aviation-grade aluminum alloy or steel, with a compressive capacity of more than 10 tons (such as the Weilai battery pack can withstand a 2-meter fall impact). Thermal barrier layer: Aerogel is filled between the cells (the thermal insulation performance is 3 times that of traditional materials) to prevent the spread of fire in a single cell (such as the “volcanic stone” thermal insulation layer of Ideal Auto).
3 Intelligent safety (the key role of BMS):
Real-time monitoring: Detect the cell voltage and temperature every 2 milliseconds, and immediately cut off the circuit if abnormalities are found (such as the battery warning function of Xiaopeng XNGP system).
Active cooling: Through liquid cooling pipes (such as Tesla’s serpentine cooling system), the temperature is quickly cooled during fast charging or high temperature, and the temperature difference is controlled within ±2℃.
In a word: The battery is the “fuel tank” of the electric vehicle, the ternary lithium is like a “long-distance runner”, the lithium iron phosphate is like a “safety guard”, and CTP/CTC is a “space management master”.
2. Electric control system: The “brain” of the electric vehicle Function: Coordinate the work of the motor and battery, optimize power output and energy consumption, which is equivalent to the “nerve center” of the electric vehicle.
Core components:
Motor controller: adjust the motor speed and torque to achieve acceleration, deceleration, and kinetic energy recovery (recover energy and charge during braking).
Battery Management System (BMS): monitors battery voltage and temperature, prevents overcharge/over-discharge, and prolongs life (e.g. Tesla BMS can accurately control the status of each battery cell).
Vehicle Controller (VCU): intelligently distributes power and energy according to driving habits (e.g., the depth of the throttle) (e.g., giving priority to the motor’s high-efficiency range at high speed).
Key Function Examples
Kinetic Energy Recovery: When the throttle is released, the motor is reversely charged, and the battery life can be increased by 10%-20% (e.g., BYD iBooster system).
Thermal Management: Heat the battery when it is cold, and cool it when it is hot, to ensure that the battery is always at the optimal operating temperature of 25-35℃ (e.g., Weilai liquid cooling temperature control system).
In a word: The electronic control system is like a “behind-the-scenes commander”, making the motor and battery “obedient and efficient”. A good electronic control can make electric vehicles drive smoother and have a more solid battery life.
4. How to judge battery safety when choosing a car?
Look at the certification: give priority to models that have passed the needle puncture test (e.g., blade battery) and the extrusion test (no deformation under 10 tons of pressure).
Check the technology: ask about the battery type (lithium iron phosphate is safer) and thermal management system (such as BYD DiPilot’s battery temperature control).
Look at the case: refer to public collision tests (such as China Insurance Research Institute C-NCAP battery safety score), or brand battery safety accident rate data (such as Tesla’s battery fire rate is lower than that of fuel vehicles).
Summary in one sentence: Battery safety is the “lifeline” of electric vehicles. Lithium iron phosphate batteries have become the first choice for home use due to their inherent advantages, and ternary lithium batteries are also approaching the safety limit through technological upgrades. Don’t be afraid to “be serious” when choosing a car. After all, “running far” is important, and “living steadily” is more important.
5. How do the three major components affect car selection?
For home commuting: permanent magnet synchronous motor + lithium iron phosphate battery + intelligent electronic control (such as BYD Dolphin, with solid endurance and low cost).
For performance players: asynchronous induction motor + ternary lithium battery + high-performance electronic control (such as Tesla Model S Plaid, with a top speed of over 320km/h).
Northern users choose: dual motor four-wheel drive + ternary lithium battery + high-efficiency thermal management electronic control (such as Zeekr 001, -30℃ endurance attenuation <30%).
Finally, a reminder: the three major components of electric vehicles are updated quickly. When buying a car, don’t just look at the parameters. It is recommended to test drive to experience the power response, kinetic energy recovery comfort, and winter endurance test data (such as CLTC vs actual endurance discount). Understand these three points and you can avoid 80% of the pitfalls!
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