Basic structure of electric bicycle

Electric bicycles are composed of five major parts: vehicle body, electric drive device (motor), rechargeable battery, charger and control system.

Different types of vehicles have different battery placement and control forms.

(1) Car body: Since the national standard stipulates that the speed of electric bicycles is 20 kilometers per hour, there are no special requirements for the car body. Generally, it is the same as the bicycle and has the function of human riding.

(2) Electric drive device (motor): There are generally three types of electric drive modes for electric bicycles: 1. Friction drive type; 2. Central axis drive type; 3. Electric hub type. Due to the advantages of small size, light weight, low energy consumption, and high efficiency, the electric hub-type drive mode is currently mostly used in domestic electric bicycles. Motors are divided into two categories: brushless motors and brushed motors. The brushless motor is mainly a low-speed high-torque motor without transmission gears, which avoids mechanical wear and has almost no noise during operation. However, the brushless motor has a large starting current and has a complex control system structure. The brushed motor in the hub adopts advanced technology, which improves the life of the brush, the motor efficiency is high, and the electronic circuit of the control system is simple.

(3) Rechargeable batteries: There are three main types of batteries for electric bicycles, namely small sealed maintenance-free lead-acid batteries, nickel-cadmium batteries and nickel-metal hydride batteries, small sealed maintenance-free lead-acid batteries with low use cost, large capacity, It is widely used by domestic enterprises.

(4) Charger: The charger design adopts three-stage automatic conversion mode of constant current, constant voltage and floating charge, which protects the battery and effectively prolongs the battery life.

(5) Control system: The control system is designed with a number of protection functions, such as power display, wireless speed regulation, soft start, undervoltage protection, overcurrent protection and brake power failure. To protect the motor and battery, the current can be output in a controlled manner to generate the required power without burning the motor. At present, most of the electric bicycles developed in China use the manual speed control handle to determine the power supply method by themselves.