The chief executive of Nio has driven an all-electric ET7 some 650 miles (1,044 km) on a single charge, demonstrating the potential of its semi-solid state 150 kWh battery pack.

William Li teamed up with the director of Nio Power Shen Fei and a Tencent reporter for the journey, live-streaming every second of it. The trip started at a battery swap station in Shanghai and after 14 hours, including 12.4 hours of driving, the duo ended their journey near Xiamen at the Longjudong Service Area. It finished the trip with a 3 percent range left.

Car News China reports that for 92% of the journey, the ET7 was being driven by Nio’s Navigate-on-Pilot+ semi-autonomous driving system and capped at 90 km/h (56 mph). It averaged just 13.2 kWh/100 km and clocked an average speed of 83.9 km/h (52 mph). The test was conducted in cool conditions with the temperature ranging between -2 °C and 12 °C (28 – 54 °F).

The semi-solid state battery offered for the ET7 has been developed and manufactured by WeLion New Energy Technology and has a single-cell energy density of 360 Wh/kg or 260 Wh/kg over the entire pack. It is much more densely packed than Nio’s current 100 kWh pack and shares the same dimensions while weighing just 20 kg (44 lbs) extra.

Read: Nio Inks Battery-Swapping Deal with Geely, Boosting EV Network Growth

The manufacturer has not yet started customer deliveries of ET7 models with the 150 kWh battery pack, and nor has it confirmed pricing details. Nio president Qin Lihong has previously suggested the pack alone will cost the equivalent of an ET5 sedan, or almost 300,000 yuan (~$42,000).

“The completion of this endurance challenge proves the product power of the 150kWh ultra-long endurance battery pack,” Li said in a Weibo post after the journey. “More importantly, all models on sale can be flexibly upgraded to 150kWh batteries through the Nio battery swap system.”

 Nio CEO Drives ET7 For 650 Miles On A Single Charge