Harness Protection Design of New Energy Vehicle Charging Interface

The water-resistance of the wiring harness of new energy vehicles is an important factor that affects the charging function of the vehicle. The design plan is to meet the electrical protection level system. The IP (INGRESS PROTECTION) protection level system is drafted by the IEC (INTERNATIONAL ELECTROTECHNICAL COMMISSION). Its dust-proof and moisture-proof properties are graded. The IPXX degree of protection is composed of two numbers. The first number indicates the degree of protection against dust and foreign objects, and the second number indicates the degree of airtightness of the appliance against moisture and water immersion. The larger the number, the higher the protection level. In the past few years, the protection level required by the OEMs was not high. With the continuous emergence of new energy vehicles on the market, the requirements of the OEMs are getting higher and higher. Now the wiring harness protection level design requirements of the new project models must meet IPX8 Therefore, the wire harness protection design of new energy vehicles will be a very important technical requirement.

The single wire seal manufacturer mainly explains two aspects of the protection design components required for the wire harness and the introduction of the protection design method.

1 The charging interface harness requires protective design components

Connector protection: The high-voltage connector is mainly responsible for the high-voltage charging system and powertrain system of the vehicle. Once water and dust enters, it will cause the loss of main functions of the vehicle or electric shock. Therefore, the protection level is extremely high. The connector design Plants, wiring harness manufacturers, and OEMs will pass the vehicle test after strict protection tests.

The low-voltage connector generally assumes the role of signal transmission. If the protection fails, it will cause the loss of some functions of the vehicle, such as charging, air conditioning, on-board system, etc., which will also have a great impact on the normal use of the vehicle, so the low-voltage connector also needs Ensure the protection requirements required by the OEM, generally IP67 requirements.

Charging interface protection: The charging interface is responsible for the charging of electric vehicles. This part must also meet certain protection requirements, generally IP54.

Cable protection with shielding net: Cables are also parts that need to be protected in recent years. When cables and connectors with shielded nets are used, the entire cable and connectors are also used as a protective design, which generally does not cause problems. However, in some charging interface designs, the shielding net is not used as a protection design. The other end of the shielding layer is connected to the connector. In extreme environments, water may leak into the connector through the cable shielding net, causing vehicle insulation failure. Therefore, cables with shielded nets also need to be considered for protection requirements.

Protection of electronic lock: Electronic lock is the standard configuration of AC charging socket, which is responsible for preventing the operation of charging without being inserted in place during AC charging. Water leakage will cause the internal mechanism of the electronic lock to fail to operate normally, and the vehicle cannot be charged because it cannot be locked.

Automotive Wire Harness Seals

2 Introduction to the design and protection of the charging interface harness

Sealing gasket protection design method: The gasket should be mainly on the high-voltage connector, low-voltage connector, charging interface and other devices.

The main protection design of the high-voltage connector is a sealing ring seal. The sealing ring is made of silicone rubber. The tail depends on the protrusion design of the sealing ring and the interference of the connector housing to produce a sealing effect. The plug-in end adopts a built-in sealing ring and the plug-in housing. The amount of interference produces a sealing effect.

Low-voltage connectors are generally sealed with gaskets and wire glue plugging. The plug-in end is generally sealed with a sealing ring and the plug-in housing to form a sealing effect. The head is generally plugged between the cable and the housing hole by rubber wire. Form a sealing effect.

From the actual use effect, both the high-voltage connector and the low-voltage connector can meet the protection level of IP67. The general protection design of the charging socket is divided into a metal plug sleeve and a waterproof sealing ring design, and the end of the socket is sealed with a gasket and the cable to form a sealing effect.

Adhesive protection design method: Adhesive is mainly used in the control box, electronic lock, charging interface and other locations that need to be sealed in space, and also in the screw hole, component socket and other locations for glue sealing. The choice of glue mainly includes silicone rubber, epoxy resin, Nanda 87 silicone rubber and other glues. The dispensing methods are mainly manual dispensing machines, automatic dispensing machines, two-component dispensing machines, etc., which can be configured according to specific needs.

Sealing strip protection design method: The main application of sealing strips is similar to that of glue. It is mainly used in fuse boxes and electronic locks that require space sealing.

Automotive wire harness seals are mainly made of ethylene propylene diene rubber (EPDM) and polyvinyl chloride (PVC), and the sealing strips are mainly divided into the integral bulk type and molded type. The bulk type is that the incoming material is in rolls, and it is used for secondary cutting as required, and then assembled to the required position. It can be used during sample trial production. One-piece molding is customized according to the required position, the required shape has been determined, and it can be directly assembled when used, and it can be used in mass production.

Heat-shrinkable hose protection design method: Heat-shrinkable hose is mainly used for cable protection. It covers the surface of the cable by melting and overflowing the heating glue. The inside of the cable is isolated from the outside world. It can not only be waterproof and dustproof but also increase the resistance of components to the outside world. ability. There are also many types of hot melt hoses, and the heat shrinkage ratio is mainly divided into 2:1, 3:1, 4:1, and so on.

Plastic ultrasonic welding protection design method: The main principle of plastic ultrasonic welding is that high-frequency vibration is delivered to the location that needs welding so that high-frequency vibration between the plastics is generated, and the plastic is welded. After completion, the plastic shell becomes a whole, which can be dustproof and waterproof. The disadvantage of increasing the strength of the plastic shell is that it cannot be reworked once the welding is completed.

Conclusion: The protection of the wiring harness of new energy vehicles is very important. This article will introduce two aspects of protection design components and protection methods. It is hoped that it may help automotive wiring harness engineers to understand the importance and necessity of automotive wiring harness protection, and to consider the protection requirements of the wiring harness in the subsequent wiring harness design and manufacturing process to ensure the normal operation and safety performance of the vehicle.