full electric cars are composed of seven parts: on-board power supply, battery pack management system, power auxiliary facilities, motors, controllers, chassis and body. The traditional division method of automobile structure is followed. full electric cars can also be divided into motors, chassis, body and body. Four parts of electrical equipment. Figure 1 shows the main assembly layout of a typical full electric car.
The electric motor is the power unit of a full electric car. It is an electromagnetic device that realizes electric energy conversion based on the principle of electromagnetic induction, and is represented by the letter M in the circuit. Its main function is to produce rotational motion, which is used as a power source for electrical equipment or various machinery.
The main function of the generator is to convert mechanical energy into electrical energy, which is represented by the letter G in the circuit.
(3) Cooling system
The cooling system generally consists of a radiator, a water pump, a fan, a thermostat, a coolant temperature gauge, and a water drain switch. full electric car motors use two cooling methods, namely air cooling and water cooling. Generally, full electric car motors use water cooling.
(4) Transmission system
As shown in Figure 2, because the motor has good traction characteristics, the transmission system of a full electric car does not need a clutch and a transmission. The car speed control can be realized by changing the speed of the motor through the speed regulation system by the controller.
(5) Driving system
The driving system is similar to that of a fuel car, mainly including frame, axle, wheels and suspension.
The function of the full electric car driving system is to receive the torque transmitted by the motor through the transmission system, and through the adhesion between the driving wheel and the road surface, generate the traction of the full electric car on the road surface to ensure the normal driving of the whole car. In addition, it should mitigate the impact and vibration caused by uneven roads on the body as much as possible to ensure the normal driving of full electric cars.
(6) Steering system
The function of the full electric car steering system is to maintain or change the direction of the car. The steering system includes components such as steering control mechanism, steering gear and steering transmission mechanism.
The steering system is composed of steering wheel, steering gear, steering knuckle, steering knuckle arm, tie rod and straight tie rod. When a full electric car is steering, it is necessary to ensure that there is a coordinated angle relationship between the steering wheels. The driver keeps the car in a straight or turning motion state by manipulating the steering system, or converts between the above two motion states; it is also necessary to ensure that the steering wheel does not vibrate, the steering wheel does not swing, and the steering Sensitive, small minimum turning diameter, easy to operate.
(7) Braking system
Braking system is the general term for all braking and deceleration systems equipped with full electric cars. Its function is to reduce the speed or stop the driving of full electric cars, or to keep the stopped full electric cars still.
The braking system includes brakes and brake transmission devices. The brake system of modern full electric cars is also equipped with anti-lock braking. Similar to fuel cars, the brake system of full electric cars is also composed of two sets of service brakes and parking brakes.
(8) Electrical equipment
The electrical equipment of full electric cars is mainly composed of battery packs, generators, lighting fixtures, instruments, audio devices and wipers.
①Battery pack. The function of the battery pack is to supply electricity to the motor. In order to meet the needs of full electric cars for high voltage, full electric cars generally use a power battery pack formed by multiple 12V or 24V battery strings and parallels as the power source. The voltage of the power battery pack is 155 ~ 400V. The charging to supplement the electric energy. The power battery pack is the key equipment of full electric cars, and its stored electric energy and its own mass and volume have a decisive influence on the performance of full electric cars.
The power battery pack occupies a large part of the effective loading space in full electric cars, and it is quite difficult to arrange it. There are usually two forms of centralized arrangement and decentralized arrangement. GM’s EV-1 full electric car uses Delco battery packs in a centralized arrangement, and the power battery pack’s support is a T-shaped frame (see Figure 3). The T-shaped frame is installed under the floor of the car and on the frame under the luggage compartment. The power battery pack is fixed on the T-shaped frame with good stability. It is installed from the rear of the car. The T-shaped frame is equipped with the ventilation system of the power battery pack and the wire protection cover, etc., and the automatic circuit breaker and the manual circuit breaker are used to cut off the power when the car is stopped or the car fails to ensure the safety of the high-voltage circuit.
The RAV4 EV of Toyota Motor Corporation of Japan uses a bracket to fix the power battery pack on the frame of a full electric car. The power battery pack consists of 24 12V Ni-MH batteries with a total voltage of 288V. The power battery packs are divided into several groups. “, are arranged in a decentralized manner on the frame, and then connected in series, so that the effective space on the car chassis can be fully utilized. The distributed arrangement of typical power battery packs is shown in Figure 4. It is the most common method to arrange the power battery pack under the floor of a full electric car, which is convenient for installation and disassembly.
② Lamps and meters. Lamps and meters are a combination of components that provide lighting and display the status of the car. The instrument can generally display information such as power battery voltage, car speed, driving status and lamp status, and intelligent instruments can also display the failure of various electrical components of the car.
(9) Energy recovery system
The function of the energy recovery system is to convert the inertial mechanical energy during the sliding into electric energy when the full electric car is sliding, and store it in the capacitor or charge the power battery, which can quickly release the energy during use.
(10) Cooling system
Because the battery generates a lot of heat during the operation of the car, it is important to have a good heat dissipation system, whether it is for the safety of a full electric car or the life of the battery.
Most of the full electric cars produced by Hyundai are modified from existing fuel cars, and the entire body structure is basically the same as that of traditional car models. Most of the full electric cars produced in the early days were mini-cars, and their body was divided into two parts: the front part and the compartment.
The carriage is modified according to customer needs, including carriage configuration, materials and space design.
In order to maximize the comfort of passengers, full electric cars generally adopt single-seater side by side. As for the number of seats, it varies according to the specific model. With the development of full electric cars in the direction of B-class cars and SUVs, the space size of the passenger compartment has a tendency to increase, and the number of seats can also increase.
(12) Industrial installations
Industrial devices are specially set up on industrial full electric cars to complete work requirements, such as lifting devices, masts, forks, etc. of electric forklifts. The lifting of the forks and the tilting of the mast are usually completed by a hydraulic system driven by a motor.