Structure and composition principle of pure electric vehicle Introduction of pure electric vehicle system

The electric car has been out for so long that everyone must be curious. The following small series will introduce you to the knowledge of the structure and composition principle of pure electric vehicles, so that everyone can have a deeper understanding of electric vehicles. Pure electric vehicle refers to a vehicle that is powered by rechargeable batteries (such as lead-acid batteries, nickel-cadmium batteries, nickel-hydrogen batteries or lithium-ion batteries) and driven by a motor. The power system of pure electric vehicle is mainly composed of power battery and drive motor, which can obtain electric energy from the power grid or replace the battery. The structure principle of pure electric vehicle The traditional internal combustion engine vehicle is mainly composed of four parts: engine, chassis, body and electrical equipment. Compared with fuel vehicles, the structure of pure electric vehicles is mainly to increase the electric drive control system and cancel the engine. The transmission mechanism has changed. According to the different driving modes, some parts are simplified or cancelled, and new mechanisms such as power supply system and driving motor are added. When the car is running, the battery outputs electric energy (current) and the controller drives the motor to run. The torque output by the motor drives the wheels forward or backward through the transmission system. Pure electric vehicle system The basic structure of a pure electric vehicle is relatively simple, and it is mainly composed of a power battery and a motor. Due to the change of system function of pure electric vehicle, pure electric vehicle consists of four new parts: electric drive control system, chassis, body and auxiliary system. Comprises a power supply system, a driving motor system, a vehicle controller and an auxiliary system. The power battery outputs electric energy, and the motor controller drives the motor to run to generate electricity, which is then transmitted to the driving wheel to drive the electric vehicle through the reduction mechanism. The power battery, the transmission and the motor are electrically connected; The motor, reducer and wheel are mechanically connected. Structure of pure electric vehicle Generally speaking, if the electric vehicle is regarded as a large system, the system is mainly composed of electric drive subsystem, power supply subsystem and auxiliary subsystem. The double line in fig. 3 indicates the mechanical connection; Thick lines indicate electrical connections; The thin line control signal is connected; The arrow on the line indicates the transmission direction of the power supply or control signal. The signal from the accelerator pedal is input into the electronic controller, and the output torque or rotational speed of the motor is adjusted by controlling the power converter. The output torque of the motor drives the wheels to rotate through the automobile transmission system. The charger charges the battery through the charging interface of the car. When the car is running, the fan battery supplies power to the motor through the power converter. When the electric vehicle adopts electric braking, the driving motor runs in the power generation state, and part of the kinetic energy of the vehicle is fed back to charge the battery, thus prolonging the driving range of the electric vehicle. Composition and control principle of power supply system for electric vehicle (1) The power supply system mainly includes power battery, battery management system, vehicle charger and auxiliary power supply. Power battery is the power source and energy storage device of electric vehicle, and power battery is the power source of electric vehicle. At present, pure electric vehicles are mainly lithium-ion batteries (including lithium iron phosphate batteries and ternary lithium-ion batteries). The battery management system monitors the use of the power battery in real time, detects the state parameters of the power battery, such as terminal voltage, internal resistance, temperature, battery electrolyte concentration, battery remaining capacity, discharge time, discharge current or discharge depth, and adjusts and controls the temperature according to the requirements of the power battery for the ambient temperature. Current limiting control can prevent the power battery from being overcharged and overdischarged, display and report relevant parameters, signal flows to the auxiliary system, and display relevant information on the instrument cluster, which is convenient for the driver to switch the vehicle charger from the power supply system of the power grid to the charging system of the power battery at any time, that is, to convert alternating current (220V or 380V) into DC with corresponding voltage (240 ~ 465,438+00 V). And control its charging current as required (household charging is generally 10 or 16A). Auxiliary power supply is generally 12V or 24VDC low-voltage power supply, which mainly provides the required energy for various auxiliary equipment. Power subsystem is the core of electric vehicle, and it is also the biggest difference from internal combustion engine vehicle. The drive system is generally composed of electronic controller, power converter, drive motor, mechanical transmission device and wheels. The drive system efficiently converts the electric energy stored in the battery into the kinetic energy of the wheels, thus propelling the car and realizing regenerative braking when the car slows down or goes downhill. The drive motor system consists of a drive motor and a drive motor controller, and is electrically and thermally connected with other systems of the whole vehicle through high and low voltage wire harnesses and cooling pipelines. The function of the drive system is to efficiently convert the electric energy stored in the battery into the kinetic energy of the wheels, so as to propel the car when it decelerates or brakes downhill and realize regenerative braking. The function of the driving motor is to convert the electric energy of the power supply into mechanical energy, and drive the wheels through the transmission device or directly. DC series motors are widely used in early electric vehicles, which have "soft" mechanical characteristics and are very suitable for driving.