The breakthrough growth of new energy vehicles has promoted the development of the wire harness industry. The automobile wire harness market has gradually shifted from low-cost to high-tech wire harness market. The wire harness processing technology, processing technology and processing equipment will undergo a new round of upgrading. With the gradual improvement of the production process, as the main connection and transmission system for vehicle signal transmission, vehicle power supply, and vehicle function realization, the manufacturer of electric vehicle harness is facing the test of layout orientation in the design process.

Function and arrangement principle of high-voltage wire harness

The high-voltage wire harness of electric vehicles can be divided into motor high-voltage wire, battery high-voltage wire, charging high-voltage wire, etc., mainly providing high-voltage and strong power supply for new energy vehicles. Layout principle: the voltage of high-voltage harness has exceeded the safety voltage of human body, and the vehicle body cannot be used as the grounding point of the whole vehicle, and the two-track system must be strictly implemented; High voltage resistance, good waterproof performance, loop interlock, shielding layer connection and other functions can be considered in the selection of high voltage harness connectors for electric vehicles.

Layout principle of low-voltage harness

The low-voltage harness of new energy vehicles not only meets the functions of traditional vehicles, but also is responsible for the realization of the functions of the high-voltage control unit module. However, the interference caused by the high-voltage harness should be considered and protected. Different signal sources use different low-voltage shielded wires. Selection of shielded wires in the low-voltage harness layout scheme: twisted pair, shielding layer and foil layer shielding are used for high-frequency signals; The low-frequency signal is shielded by twisted pair, shielding layer and braid layer. The grounding form of shielded conductor can be selected: single-point grounding is adopted for low-frequency signal; Multi-point grounding is adopted for high-frequency signal.

High and low voltage harness layout area

Engine compartment: PDU, drive motor, electric compressor and other high-voltage harnesses are concentrated in the vehicle harness. Low voltage harness of MCU, VCU, DC-DC and various sensors;

Cab: based on the traditional car layout structure;

Luggage compartment: mainly including low-voltage harness units such as charging high-voltage line, power battery control system, on-board system, etc.

High and low voltage harness layout structure

(1) Layered arrangement: the high voltage harness and low voltage harness are divided into upper and lower layers. In order to avoid the risk of electromagnetic interference caused by high voltage harness transmitting strong current, which leads to the risk of electromagnetic interference caused by low voltage harness to the power supply and signal transmission of the control unit, the hierarchical design of high voltage harness and low voltage harness is generally adopted, and the distance is guaranteed to be within 200-300mm.

(2) Parallel arrangement: they have the same trend, but are arranged in parallel through the body mechanism. The parallel wiring scheme is applicable to hybrid electric vehicles. The wiring area of the high-voltage harness connection unit is parallel to the layout area of the engine EFI harness. So as to effectively avoid the electromagnetic interference generated when the high-voltage harness transmits power.