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Solid-state batteries ran underground for a year at 85°C
A Beijing solid-state battery system operated for a year in an underground heating network at up to 85°C and 95% humidity.
Image: iXBT
A stationary solid-state battery system in Beijing kept running after one year underground in a district heating network, enduring a winter cycle with temperatures of up to 85°C and humidity levels of 95%.
The test is a rare example of field use rather than a lab demonstration. According to Beijing Energy Group, the system maintained stable operation at sustained temperatures from 40°C to 85°C and humidity from 90% to 95% while deployed in a working heating network throughout the winter season.
The project focused on how well the batteries could withstand harsh industrial environments. But the data released so far leaves major gaps: the company did not disclose the batteries' chemistry, energy capacity, degradation data, or service life metrics.
The report also draws a clear line between this result and automotive use. While the underground deployment highlights durability in heat and moisture, EV batteries are judged on a different mix of priorities, including energy density, weight efficiency, fast charging, manufacturing cost, and longevity.
The battery system was developed by Pure Lithium New Energy, a Beijing-based solid-state battery developer in the Yizhuang Economic and Technological Development Zone. The company introduced its first solid-state battery system in 2025, initially targeting battery-swapping networks for electric bicycles.
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Dan is our resident futurist, covering electric mobility, space exploration, and the smart home. He's interested in atoms just as much as bits. Whether it's a new battery chemistry, a reusable rocket, or a protocol that finally makes IoT devices talk to each other, Dan breaks down the engineering that pushes humanity forward.
via iXBT
