Cost, cost, cost!! The application of aluminum wiring harness in new energy vehicles from Xiaomi SU7

 Xiaomi car has responded to questions about the use of aluminum wiring harnesses instead of copper wiring harnesses for the Mi SU7 model. At present, most automakers choose aluminum conductors in components such as charging wiring harnesses, and the Xiaomi SU7 also follows this trend, Xiaomi said. Aluminum conductors are similar to copper conductors in conductor performance and safety performance, but the conductivity is different, but the same current carrying capacity can be achieved by adjusting the cross-sectional area. Compared with copper conductors, aluminum conductors have the advantage of lightweight, which is about 30% lighter, which is conducive to improving the mileage of the car. Xiaomi stressed that the choice of this material is based on industry trends and is not cutting corners.

In addition, experts and parts manufacturers also said that the replacement of copper wire bundles by aluminum in new energy vehicles is not cutting corners, but based on the following considerations:

1) the material cost of aluminum is relatively low, which is conducive to cost control and market expansion;

2) Aluminum soft connection can reduce the weight of the battery pack and improve the driving range of the car;

3) Aluminum has good flexibility and processability, suitable for different thickness of product types;

4) Aluminum soft connection has strong antioxidant capacity, which is conducive to maintaining stable electrical conductivity;

5) The heat capacity of aluminum is low, which is conducive to heat dissipation and can improve the working efficiency of the battery pack. Therefore, despite the shortcomings of aluminum in some aspects, it is still the preferred material in new energy vehicles through appropriate technical applications, such as the selection of high-current wires for battery packs, inverters and motor connections.

But for Xiaomi's response, netizens did not pay.

"Do not take the trend of the industry as a shield, the trend of the industry is not necessarily correct, take consumers as guinea pigs"

"Copper clad aluminum, iron clad steel"

"High-end car copper, low-end car aluminum, absolutely!"

"Cost, cost, in the end it's all about the capitalists saving costs."

The application of aluminum wiring harnesses in new energy vehicles is gradually increasing, but it has not reached the level of universal use.

At present, automobile wiring harness is mainly based on copper wire, especially in the power input and output of new energy vehicles, motor electronic control parts and other important parts. However, with the improvement of cost control and lightweight requirements for new energy vehicles, the development of aluminum wires has received the attention of the industry.

Advantages of aluminum wire compared with copper wire:

Compared with copper wire, aluminum wire has a small density, and the weight of aluminum wire is lighter under the same length, which is one of the trends of lightweight development of wire harnesses. The comparison of the properties of copper and aluminum is shown in Table 2. The density ratio of copper and aluminum is 10:3, and the volume of 1t aluminum wire is equivalent to about 3.3t copper wire.

Global copper reserves are much smaller than aluminum, so copper prices are higher than aluminum, and copper prices are rising, aluminum prices are relatively low and less volatile. The production cost of automobile wire harness can be reduced effectively by using aluminum instead of copper.

Compared with copper wire, aluminum wire has disadvantages:

(1) High resistivity Aluminum has a higher resistivity than copper, which means that at a given voltage drop, aluminum conductors must have a larger cross-sectional area.

(2) Low mechanical strength aluminum wire is soft and flexible, and poor vibration resistance. Under the same conditions, the tensile strength of aluminum is only half that of copper, which affects the crimp pulling force of the terminal.

At present, the application cases of aluminum wiring harnesses in new energy vehicles are rich and diverse, covering different vehicle types and electrical system components. Here are some specific application examples:

Bus battery pack inside/outside: In large new energy buses, the battery pack is an important energy storage unit, and its internal and external connections need to withstand the transmission of large current. Because of its light weight and high conductivity, aluminum wire harnesses are ideal for connecting inside and outside battery packs. This not only reduces the overall weight of the vehicle, but also improves the efficiency and stability of the battery system.

Dc bus for passenger models: In new energy vehicles for passenger models, the DC bus is an important part of the connection between the battery pack and the motor controller. The use of 50mm² cross-sectional aluminum cables can significantly reduce the weight of the wiring harness, while improving the electrical contact performance of the joint through ultrasonic welding technology, ensuring the reliability and efficiency of the bus.

Ac charging gun: AC charging gun is an essential equipment for daily charging of new energy vehicle users. The charging gun made of high-strength bending aluminum alloy wire is not only lightweight, but also has excellent aging resistance and corrosion resistance, ensuring long-term stability and safety.

High voltage aluminum flat strip harness: With the development of new energy vehicle technology, the application of high voltage and high current harness is more and more extensive. The high pressure aluminum flat strip harness was developed to reduce the weight and cost of the harness while maintaining high reliability and excellent electrical conductivity. The technological innovation of Changchun Jieyi and other companies in this field has provided more choices for the new energy vehicle industry.

These application cases demonstrate the important position of aluminum wiring harnesses in new energy vehicles. The light weight, low cost, abundant resources and good electrical conductivity of aluminum wire harness make it the preferred material for the design of electric system of new energy vehicles. With the continuous progress of technology and the further reduction of costs, it is expected that the application of aluminum wiring harnesses in new energy vehicles will be more extensive, helping to promote the development and innovation of the new energy vehicle industry.