New Energy Vehicle Interior Wiring Harness Design and Wire Requirements

The application scenarios of New Energy Cable Assembly mainly include in-vehicle cables, charging guns/charging piles, and on-board chargers. The in-vehicle high-voltage Wire Harness is mainly used to provide high-voltage and strong power supply for new energy vehicles, which are high in new energy vehicles. Safety parts have the characteristics of high voltage/high current and large number of wires with large diameters, which also makes the design of high-voltage wiring harnesses in new energy vehicles face many challenges. Today, let's take a look at the Wiring Harness design and wire requirements of new energy vehicles.
1. Basic characteristics of high-voltage wiring harness in the car
1.1 High voltage/high current
The battery voltage of new energy vehicles can reach 600V, and the corresponding wire withstand voltage level is 300A. The battery voltage of traditional fuel vehicles is generally 12V, and the corresponding wire withstand voltage rating is less than 60V.
1.2 Large number of wires with large diameter
New energy vehicles need to use large-diameter wires in high-voltage batteries, inverters, transformers, low-voltage batteries, air-conditioning compressors, etc., and the number is very large.
2. Challenges faced by high-voltage wiring harnesses in vehicles
Due to the characteristics of high voltage/high current and large number of wires with large diameter, the high-voltage wiring harness in the car faces challenges in safety, wiring, shielding, weight and cost. Faced with these challenges, we have summarized some countermeasures.
2.1 Security
Faced with safety challenges, some countermeasures need to be taken in the selection and sealing of wires in the car
(1)Wire selection
Adopt high-voltage wire 600V/900V (AC) (refer to ISO19642);
Adopt wall thickness high line, wall thickness 0.6mm-1.1mm;
Using heat-resistant wire, heat-resistant 150 degrees or more
Optional silicone rubber wire, cross-linked polyethylene/cross-linked polyolefin material
(2)Sealing
Matching with high-voltage connectors, it is sealed by wire seals, heat shrinkable tubes, Pass-thru seals, rubber parts, etc. to be waterproof and dustproof (IP67, IP69K). The wire is required to have good roundness, dimensional stability and aging performance.
2. Wiring
The layout of the high-voltage wiring harness in the vehicle has the following requirements:
(1) In the case of static load, the minimum turning radius is 4 times the outer diameter of the wire;
(2) In the case of dynamic load, the minimum turning radius is 8 times the outer diameter of the wire;
(3) The minimum distance between high and low voltage wires is not less than 100mm;
(4) The distance from the outlet end of the high-voltage Connector to the first fixed point is not more than 100mm, and the distance between adjacent fixed points is generally not more than 150~200mm;
(5) The high-voltage wiring harness is arranged at the bottom of the vehicle as much as possible;
(6) Wire selection toughness wire such as silicone rubber wire, flexible cross-linked polyolefin wire.
3. Shield
Because of the electromagnetic field interference caused by the high voltage and large AC of the new energy vehicle, as well as the electromagnetic interference caused by the rapid switching of electrical components, considering the factors of electromagnetic interference, the entire high-voltage system is completely covered by the shielding layer. Then the measures for shielding electromagnetic interference of high-voltage wiring harnesses are:
3.1 Use shielded wire
The ultra-high current and voltage of electric vehicles will produce a large electromagnetic induction phenomenon during operation. If the electromagnetic shielding problem is not well solved, it will inevitably affect the performance of automotive electronic equipment. Nice choice.
The shielded wire is braided by multiple strands of tinned annealed copper wire. The thin copper wire can maintain the designed flexibility and has a coverage rate of more than 90%. It is necessary to control a reasonable insulation and sheath peeling force to meet the requirements of wire-opening and wire-stripping.
3.2 Bundle Shielding
For the overall shielding, the wire is unshielded, and it is mostly used by Japanese OEMs at present.
Bundle Shielding refers to protecting the wire bundle from electromagnetic interference when a light braided metal shielding layer is used outside the wire harness as a shielding member.
3.3 Aluminum tube shield
The aluminum tube shielding also belongs to the overall shielding, and the wire is unshielded, which is currently mostly used by Japanese and American OEMs.
4. Weight
For new energy vehicles, lightweight is very important for the improvement of cruising range. Then the weight of the wire harness can be started from the selection of materials. The conductor material can be selected from new wire conductors, such as new aluminum wires; the insulating material can be selected from low-density materials and thin-walled processing.
5. Cost
At present, the high-voltage wires in the car are mainly imported, and the threshold for wires is relatively high. The output of mass-produced models in the early stage is relatively small. New energy vehicles face greater cost pressure and need to develop more domestic resources.
6. Environmentally friendly
The high-voltage wiring harness in the car needs to use low-volatile, low-VOC, low-odor materials.