The world's largest EV battery maker CATL may be on to something as in the near future it said it is betting on cells with semi-solid electrolyte, rather than pie-in-the-sky true solid-state batteries, whose mass production on the cheap may not happen before 2026.

When NIO approached its main battery supplier CATL to jointly develop a 150 kWh pack with semi-solid electrolyte, CATL declined over costs and resource availability. NIO then partnered with startup WeLion and developed the 150 kWh semi solid-state battery pack, but its mass production went over deadlines and budgets several times, just as CATL predicted.

In any case, NIO just started producing its battery with 95% solid-state electrolyte in meaningful enough quantities to install in its future vehicles, and first in line is the refresh of its ET7 premium sedan that will be announced on April 25.

NIO ET7 solid-state battery range test

To celebrate the occasion, NIO ran the first official real-life EV range test with the solid-state battery in the ET7. Previously, its CEO ran one improvised testing on the highway and the 150 kWh managed to propel the sedan for more than 650 miles on a charge on the highway.

Now, however, the three separate solid-state battery range tests with the new ET7 now cover different itineraries and various driving condition mixes. Still, the car managed to run for at least 650 miles on a charge in all situations, returning a very impressive 13.0 kWh/100 km consumption rate.

For comparison, Tesla lists a similar 13 kWh/100km rate for the much smaller and slower Model 3 Highland, while the heavier Model S that is a more direct ET7 competitor, consumes 17 kWh/100km.

NIO's semi solid-state battery range tests returned an average speed of about 80km (50 miles) per hour, and 75mph peak in a typical leisurely driving within the speed limits scenario. In all situations, even at mountainous elevation, the temperatures were above 15 degree Celsius (60 Fahrenheit).

Now, the only missing piece of the puzzle is the price that NIO will charge for the ET7 with its innovative 150 kWh battery pack with semi solid-state electrolyte.

Previously, it pegged the pack to be as expensive as its smaller ET5 sedan itself, but now that mass production has started, the manufacturing costs may have declined.

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