WeLion advances semi-solid-state batteries for vehicles and ships

WeLion New Energy is developing semi-solid-state batteries that use a part-liquid, part-solid electrolyte, aiming to improve safety and energy density compared with conventional lithium-ion cells that rely on flammable liquid electrolytes. The Beijing-based company, founded in 2016, is pursuing applications across electric cars, boats and drones while fully solid-state cells remain difficult to manufacture.

In 2023, WeLion and Shanghai EV maker Nio released a battery pack with an energy density of 360 watt-hours per kilogram (wh/kg), above the 200 wh/kg average cited for lithium-ion packs today. The pack enabled a range of over 1,000 kilometers (621 miles), though only about 200 were produced because of high costs. WeLion also says its engineers tested a semi-solid-state battery reaching 824 wh/kg in 2025.

The company faces cost and scale challenges in a crowded Chinese battery market, and its 2025 prototype remains far from commercialization with unanswered questions about cycle life and degradation. WeLion plans a drone battery with 410 wh/kg by the end of this year and an all-solid-state car battery with 400 wh/kg in 2027. Inland cargo ships using its packs are expected in October 2026, while annual manufacturing capacity stands at 11 gigawatt-hours (GWh) with 18 GWh under construction.