WeLion New Energy is developing semi-solid-state batteries to improve safety and energy density over conventional lithium-ion cells. These batteries use a part-liquid, part-solid electrolyte, reducing flammability risks while enabling greater energy storage. In 2023, WeLion partnered with Shanghai-based EV-maker Nio to release a battery pack with 360 Wh/kg energy density, offering over 1,000 kilometers range—significantly higher than today’s 200 Wh/kg average.
Only about 200 packs were produced due to high costs, but they remain in use by Nio. The company has also built batteries for cargo ships and ferries through a subsidiary. In 2025, WeLion’s engineers tested a semi-solid-state battery achieving 824 Wh/kg, more than triple the density of standard lithium-ion batteries.
Despite lab success, scaling production and reducing costs remain major challenges. WeLion’s batteries are currently more expensive than those from larger Chinese firms like CATL. Key details such as cycle life and long-term degradation are still undisclosed.
The company plans to launch a drone battery with 410 Wh/kg by year-end and its first all-solid-state car battery with 400 Wh/kg in 2027. Two inland cargo ships powered by WeLion batteries are expected to launch in October 2026 in Huzhou.
Source: MIT Technology Review · Summarized by HeadlinesBriefing