Xiaomi SU7 mounts battery terminals upside down to cut thermal runaway fire risk

Harriet L. Whitcombe • May 07, 2026 20:35

Xiaomi is assembling its batteries in a way no one else has - quite literally. In the Xiaomi SU7, the Chinese brand’s electric saloon, the battery cells are installed with their terminals facing downwards, the reverse of what is typically done across the industry.

Xiaomi SU7 battery cells with terminals facing down

This choice is part of a deliberate push to improve safety and lower the likelihood of a fire if thermal runaway occurs - the same as a runaway thermal event, the term used for the loss of temperature control that can lead to this component catching fire.

Safety rationale in a thermal runaway event

What does Xiaomi gain from this layout? With the electrical contacts pointing down, any heat leak or flame can be directed and dispersed away from the passenger compartment. This runs counter to the usual approach, where terminals sit at the top, increasing the chance that, in a fire, the cabin is exposed to very high temperatures.

Engineering challenges and CATL’s electrolyte solution

However, turning the cells over creates fresh challenges. The first is the electrolyte’s behaviour: with the cell mounted inverted, the liquid inside responds differently under gravity.

To address this, CATL - Xiaomi’s battery supplier - developed a special electrolyte formulation tailored to the new orientation. The pack structure was also reworked into a “cell-to-body” design, integrating the battery directly into the vehicle’s structure.

Packaging benefits from structural integration

This mix of inverted cells, advanced thermal insulation and structural integration is what enables the SU7 to keep the proportions of a conventional car, without the bulky side profile typical of many electric vehicles.

When the Xiaomi SU7 is expected in Portugal

As for the Portuguese market, the Xiaomi SU7 is only expected to reach national roads after 2027. Portugal is not among this Chinese brand’s priority markets, despite it being best known for its smartphones and consumer electronics.