In new energy vehicles, there are two main measures for EMC electromagnetic compatibility of high-voltage systems. First, the high-voltage equipment is covered by a metal shell, and the shells are all connected with the body ground with equipotential equalization lines. The second is that the high-voltage wiring harness system (including high-voltage wires and high-voltage connectors) has a metal shielding layer, and the shielding layer is connected to the high-voltage equipment housing or to the body ground. The purpose of these two measures is to ensure the good electromagnetic compatibility of the vehicle.
When the pressure equipment realizes the function, electromagnetic interference is generated, that is, the noise environment. When high-voltage devices need to communicate with each other and conduct energy through high-voltage and low-voltage wiring harnesses, the high-voltage wiring harness itself and its connected interface become the way for electromagnetic interference to propagate. Therefore, almost all high-voltage wire harnesses on the market have aluminum foil or shielded braid, but many wire manufacturers and OEMs have tried to use unshielded high-voltage wires.
Before carrying out the shielding design, it needs to be clear that the shielding of the high-voltage system is not limited to the high-voltage wiring harness itself, but a systematic adjustment. It includes: high-voltage wire shielding design, high-voltage connector shielding design, high-voltage equipment interface shielding design, high-voltage equipment adding EMC filters and other measures.
The shielding function of the high-voltage wire harness is mainly realized by the aluminum foil and the shielding braid. To remove the shield means to remove the aluminum foil and the shielding braid. Since the aluminum foil and shielding braid no longer exist, the inner insulation layer of the high-voltage wire also loses its original insulation and protection function and can be cancelled together.
So far, the difference between the high-voltage wire and the low-voltage wire is only the diameter of the core and the thickness of the single (outer) insulating layer.
When the high-voltage wiring harness of the whole vehicle is changed from the state with the shielding layer to the state without the shielding layer, the following changes will be brought:
| Change point | Advantage √ Disadvantage |
| The material cost of vehicle high voltage wire harness system is reduced | √ |
| High voltage harness system(connector,harness)simplified structure | √ |
| The mode and process of mass production of high-voltage wiring harnesses are closer to low-voltage wiring harnesses | √ |
| Mass production of high-voltage wire harnesses will be easier to achieve fully automated | √ |
| Reduced vehicle manufacturing time and simplified production and logistics processes | √ |
It should be noted that the premise of shielding the high-voltage wiring harness is to ensure that the EMC of the entire vehicle cannot be reduced. Effective measures include: effective suppression of electromagnetic interference sources, such as structural optimization of high-voltage components themselves or internal EMC filters; upgrade of sensitive parts Its own anti-interference ability; the installation and arrangement of high and low voltage wiring harnesses on the body maintain sufficient distance from each other.
