First semi-solid-state 360 Wh/kg battery batch for the 620-mile range NIO ET7 proves surprisingly affordable to make

The first batch of what their manufacturer calls semi-solid state batteries with 150 kWh capacity will be delivered for placement in NIO's electric cars in September. NIO plans to use them in a promised for Q4 release version of its performance ET7 sedan that will be able to cover more than 1000 km (621 miles) on a charge with the 150 kWh packs.

Instead of chasing pie-in-the-sky statements that it will be developing solid-state batteries like most legacy automakers during their EV transition announcements, NIO found a stopgap solution. After being snubbed by CATL, NIO went to the Beijing-based battery manufacturing startup WeLion, and they developed a battery with solid-state electrolyte, silicon composite anode, and a high nickel cathode (hence the long range on a charge). The hybrid solid-liquid battery has an industry leading 360 Wh/kg energy density and will enter mass production in the fourth quarter.

Sources close to the manufacturer WeLion divulge that the semi-solid state battery pack was only slightly more expensive to produce than the liquid batteries it has done so far, boding well for the mass production stage. There are three more Chinese battery makers that have focused on this hybrid solid-state battery development and one of them, Ganfeng Lithium, the country's top refiner, even managed to deliver its own solution to a fleet of taxis for testing in real-life scenarios.

Its energy density, however, is nothing to write home about, while NIO's 150 kWh battery pack that is soon to go into its ET5 and ET7 sedans will deliver unprecedented range/performance ratio on a charge, while at the same time being able to enjoy some of the durability advantages of solid-state batteries.

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