Yangwang U8L’s one-piece aluminium frame showcases BYD’s latest engineering advancement

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Chinese electric vehicle (EV) manufacturer BYD has unveiled engineering details behind the advanced one-piece aluminium frame used in its luxury SUV, the Yangwang U8L. The company disclosed that the development programme began in 2023 and involved building what is said to be China’s largest integrated automotive casting machine, in collaboration with the aerospace-focused supplier Hantek.

The latest update sheds more light on a major milestone first highlighted earlier when the Yangwang U8L introduced the world’s first one-piece low-pressure-cast aluminium vehicle frame. The integrated structure spans nearly 4.2 square metres and incorporates wall thicknesses ranging from 4 mm to 50 mm, presenting a production challenge that many in the automotive sector had previously considered difficult to achieve with conventional casting methods. 

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The target of the engineers behind the development at BYD was to create a full-size body frame structure that would outperform existing conventional steel frames in several aspects, such as weight, durability, and strength.

The Yangwang U8L reportedly consists of aerospace-grade 6- and 7-series aluminium alloys, arranged in a structure that improves stiffness while reducing weight. Additionally, cold joining techniques such as bolting and riveting were then utilised by the company, methods that are common in aerospace production processes.

The automaker turned to Hantek, leveraging the supplier’s aerospace manufacturing expertise to co-develop an entirely new integrated casting system. The collaboration ultimately led to what BYD described as the largest integrated casting machine currently operating in China’s automotive sector.

The new manufacturing process also marked China’s first domestic use of integrated low-pressure casting technology for a large vehicle frame. Through this method, the total number of structural components was reduced from 251 to 119, while 67 rear-frame components were merged into a single casting.

Furthermore, welding length reportedly declined from nearly 100 metres to just 9 metres, helping minimise fatigue risks and reducing potential structural deformation points.

The completed aluminium structure ultimately reduced the Yangwang U8L’s weight by 56 kg while significantly increasing body rigidity. BYD claimed that the vehicle became the first in the industry to successfully clear a 12-tonne lifting test using an integrated frame system, with torsional rigidity exceeding comparable vehicles by over 50 per cent.

The announcement comes as Yangwang continues to strengthen its image as BYD’s flagship technology-focused brand. During the 2026 Beijing Auto Show, the company showcased customised versions of the U8L and U9 Xtreme. The limited-production U9 Xtreme later became BYD’s highest-priced vehicle, selling for 20 million yuan (USD 2.76 million). 

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