Xiaomi SU7 copper wire for aluminum wire, is it really "cutting corners"?

Buying a car

2024-05-06 11:50Posted in Tianjin automotive creators

Some time ago, a post called "Xiaomi car cut corners in order to save the cost of the whole vehicle", caused a heated discussion on the Internet, it is understood that the cause of the matter is that someone posted on the Internet that the charging wiring harness of Xiaomi car uses aluminum instead of copper used by traditional car companies, and in most people's impression, copper is an expensive material, at least relatively speaking, the name of aluminum wire is much more unfamiliar.

So the use of aluminum instead of copper, is it really cutting corners? Of course not, the most fundamental purpose of choosing aluminum is to reduce the weight of the car.

In fact, for a long time, "copper wire" is the main material of automotive wiring harness, it has excellent conductivity and safety stability, in the era of traditional fuel vehicles, the diameter of copper alloy wire is generally 0.35~25mm, roughly estimated that the weight of the wiring harness required by the vehicle is 25~30KG, accounting for about 2% of the total weight of the car Around, in addition to the outsourcing materials and terminals and other accessories, most of the rest are copper wires, in terms of normal fuel consumption of oil vehicles, this weight will bring about 100 kilometers of 0.1kg of gasoline consumption, in general, the fuel consumption level of the vehicle has little impact.

However, in the era of electric vehicles, this situation is changing, on the one hand, the three-electric system replaces the original engine transmission based on the mechanical structure, more electrical equipment is implanted in the car, and the connection series naturally uses more wiring harnesses, in addition to the high-voltage charging of the tram also needs to use thicker copper wires to improve the bearing capacity, which in disguise increases the proportion of wires in the weight of the whole vehicle.

In this regard, "Wang Xianbin", senior director from Gasgoo Automotive Research Institute, said: "If it is a 1.6-2 ton B-class pure electric vehicle, even if the intelligence is not high, its vehicle wiring harness usage will reach 4km, and the weight will be about 60-80kg, accounting for about 3%-5% of the vehicle weight. ”

Wiring harness increases and thickens, natural vehicle weight will also increase, and the car becomes fat for the car's braking, control has a great negative impact, so if you want to lose weight for the car, either sacrifice the battery life, or think of other ways, obviously, the use of lighter wiring harness materials, is a good way.

In the case of the same volume, copper is 3.3 times heavier than aluminum, and in the case of the same weight, the volume of aluminum is larger and the conductivity is twice that of copper, from this point of view, with aluminum instead of copper, electric vehicles can get quite good weight reduction effect without affecting or even improving performance, and in the installation process, aluminum does not need bridge and pipe, so the installation cost will also be reduced by 20% ~ 50%. If the copper price of 75,000 yuan per ton and the aluminum price of 20,000 yuan per ton are roughly estimated, car companies can save 6~7 times the cost of wire harness in this way.

In fact, subject to the degree of commercialization and cost factors, aluminum wire has not been widely used for a long time, and in recent years, with the gradual maturity of related technologies, including Tesla, BYD and other car companies are also using aluminum to partially replace the original copper wire, which is also a major reason for SU7 to use aluminum wire.

It is worth noting that the use of aluminum in Xiaomi SU7 is only in the local range such as the charging gun, not a large-scale use on the Internet, and there is no so-called reduction, and its purpose is more to prepare for the follow-up vehicle "copper for aluminum".

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