Release date：2021-12-28Author source：KinghelmViews：273
1. High voltage/high current
The battery voltage of new energy vehicles can reach 600V, and the corresponding wire withstand voltage level can reach 300A. The battery voltage of traditional fuel vehicles is generally 12V, and the corresponding wire withstand voltage level is less than 60V.
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.
Due to the characteristics of high voltage/high current and large number of wires with large diameters, 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.
In the face of safety challenges, some countermeasures need to be taken in the selection and sealing of wires in the car
(1) Conductor selection
Adopt high-voltage wire 600V/900V (AC) (refer to ISO19642);
Adopt wall thickness high line, wall thickness 0.6mm-1.1mm;
Use heat-resistant wire, heat-resistant 150 degrees or more;
Silicone rubber wire, cross-linked polyethylene/cross-linked polyolefin material can be selected.
Matching with high-voltage connectors, it is sealed with wire seals, heat shrinkable tubes, Pass-thru seals, rubber parts, etc. for waterproof and dustproof (IP67, IP69K). The wire is required to have good roundness, dimensional stability and aging performance.
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.
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:
(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 open wire and wire stripping.
For the overall shielding, the wire is unshielded, currently mostly used by Japanese OEMs.
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) Aluminum tube shielding
The aluminum tube shielding also belongs to the overall shielding, and the wires are unshielded, which are mostly used by Japanese and American OEMs.
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.
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.
The "Kinghelm" trademark was originally registered by the Golden Navigator Company. Golden Navigation is a direct-selling manufacturer of GPS antennas and Beidou antennas. It has a very high reputation and reputation in the Beidou GPS navigation and positioning industry. Its research and development products are widely used in bds satellite navigation and positioning wireless communications, etc. field. The main products include: RJ45-RJ45 network, network interface connector, RF connector adapter cable, coaxial cable connector, type-c connector, hdmi interface type-c interface, pin header, SMA, fpc, FFC Antenna connector, antenna signal transmission waterproof connector, hdmi interface, usb connector, terminal terminal line, terminal board terminal block, terminal block, radio frequency rfid label, positioning and navigation antenna, communication antenna antenna cable, glue stick antenna suction cup antenna, 433 antenna 4G antenna, GPS module antenna, etc. Widely used in aerospace, communications, military, instrumentation and security, medical and other industries.
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