Solid

A solid-state battery ran for a year underground in Beijing. Why isn’t it in EVs yet?

A Beijing Energy Group project has validated a stationary solid-state battery system after a year of underground operation within a heating network, where it completed a winter cycle at temperatures up to 85°C and humidity levels of 95%. The project demonstrates solid-state battery operation under extreme industrial conditions while also highlighting why transferring this technology to mass-market EVs requires different engineering and manufacturing solutions.

The project, titled “Research & Development and Demonstration Verification of Solid-State Battery Technology in Extreme Environments,” passed the Beijing Municipal Science and Technology Commission’s comprehensive performance evaluation on July 15, 2026. The system operated along a 1.1-kilometre section of the Shijingshan West Chang’an Avenue extension heating pipeline network.

The result provides a verified field operation case for a specific stationary energy storage application. However, it does not represent automotive battery validation, as EV applications prioritise different factors, including energy density, weight efficiency, fast charging capability, manufacturing cost, and long-term durability.

The demonstration was carried out under Beijing’s carbon neutrality technology program, with Beijing Energy Group serving as the deploying organisation. Jingneng Technology and related energy storage partners participated in the engineering work.

Unlike laboratory-only testing, the battery system operated inside an active heating infrastructure network throughout an entire winter season. According to Beijing Energy Group, it maintained stable operation under continuous temperatures ranging from 40°C to 85°C and humidity levels between 90% and 95%.

The project focused on environmental durability in a demanding industrial setting. However, the company’s disclosure does not provide details on battery chemistry, energy capacity, degradation data, or cycle-life performance.

The company behind the battery system is Pure Lithium New Energy, a Beijing-based solid-state battery developer located in the Yizhuang Economic-Technological Development Zone. The company introduced its first-generation solid-state battery system in 2025, targeting e-bike battery-swapping networks as its initial application.

According to CEO Yang Fan, the company focused on overcoming three major barriers to the commercialisation of solid-state batteries: production costs, manufacturing scalability, and commercial application. The Beijing underground deployment represents another step in applying the technology beyond laboratory environments and into specialised industrial use cases.

The deployed solid-state battery system achieved an IP68 dust- and waterproof rating and passed state-level safety certifications for non-combustion and non-explosion performance under simulated conditions.

For stationary energy storage, these characteristics address concerns around operating batteries near industrial infrastructure, where exposure to heat and moisture can affect long-term stability.

EV batteries face a different engineering challenge. Automakers must balance safety improvements with energy density, vehicle weight, charging speed, manufacturing cost, and durability under repeated driving conditions.

The Beijing project, therefore, confirms that this specific solid-state battery system can operate under harsh industrial conditions, but it does not directly demonstrate its readiness for automotive mass production.

The validation comes as solid-state battery developers continue moving toward clearer technical standards and commercial applications. China’s new solid-state battery standards took effect in July 2026, creating clearer definitions and requirements as manufacturers develop the technology.

At the same time, major battery manufacturers remain cautious about large-scale automotive adoption. CATL Chairman Robin Zeng has said solid-state batteries still face significant manufacturing challenges and remain years away from widespread commercial use in vehicles.

The Beijing Energy Group deployment demonstrates that this specific solid-state battery system can operate reliably in demanding industrial conditions. For EV manufacturers, the harder test will be whether similar technology can reach automotive-scale production while meeting cost, performance, and durability requirements.

The project shows that successful operation in a stationary industrial environment does not by itself demonstrate readiness for automotive mass production. Future EV applications will depend on whether developers can adapt solid-state battery technology to meet vehicle-specific requirements.

Source: Beijing Energy, Beijing Daily

Adrian, an Electrical and Computer Engineering graduate with a love for cars, brings expertise and enthusiasm to every test at CarNewsChina. He also enjoys audio, photography, and staying active.