BYD's 8-in-1 unit taken apart and rare earths

The reposted teardown by Yuichi Nakatani, product engineer at GM do Brasil, describes BYD's 8-in-1 assembly: motor, reducer, inverter, on-board charger, DC-DC converter, PDU, BMS and VCU in a single aluminium block, connected by copper busbars, with no external high-voltage harnesses, and with shared cooling. The video in the post attributes the compactness to the permanent magnet synchronous motor, with efficiency above 95%, and says that almost 80% of the materials cost comes from local suppliers or from BYD itself.

The video itself names the price: rare earths. The IEA's 2026 Rare Earth Elements report records China with 60% of rare earth mining for magnets in 2024, 91% of refining and 94% of sintered permanent magnet production. In April 2025, Beijing imposed export controls on seven heavy rare earths and on magnets.

Integration cuts parts, copper and assembly. Outside China, copying the design is not enough: the advantage depends on magnets and refining.

The bottleneck has moved from the harness to the magnet. Anyone planning local production needs to account for this supply chain from the design stage.