Alibaba's Server-Integrated Lithium Battery BBU System for Data Center Power Efficiency

Since the Double 11 shopping festival began in 2009, tens of thousands of servers have handled billions of transactions, requiring massive data processing in Alibaba's data centers.

To lower data‑center PUE, save energy, and improve server power‑supply efficiency, Alibaba embeds a lithium‑battery Battery Backup Unit (BBU) inside each server, replacing one of the two Power Supply Units (PSU) and forming a distributed BBU system across the data center.

This solution makes Alibaba the first Chinese internet company with server‑level backup power, joining Google and Microsoft in possessing this technology.

The left side of the image shows Alibaba's server‑integrated lithium battery BBU

Most data centers rely on centralized UPS with lead‑acid batteries, which suffer from four major drawbacks: a single UPS failure can cut power to dozens or hundreds of server racks; multiple energy conversions lower efficiency; high investment and operational costs due to over‑provisioned distribution hardware; and labor‑intensive maintenance because lead‑acid batteries require frequent charge‑discharge testing.

Alibaba's design allows the internal 12 V lithium battery to instantly supply power when external power is lost, delivering up to 99 % efficiency—about 8 % higher than traditional UPS or 240 V DC solutions—and reducing PUE by 10‑15 %.

Unlike centralized UPS, the BBU can be procured and installed together with servers, avoiding idle UPS capacity, cutting capital costs, and shortening overall data‑center delivery time by roughly 15 %.

For a 10 kW‑class data center, annual UPS operating expenses of tens of millions of yuan and upfront UPS and distribution equipment costs can be eliminated; the BBU’s 10‑15‑year lifespan versus 4‑6 years for lead‑acid batteries saves nearly half of the total cost.

Managing tens of thousands of batteries presents a major operational challenge.

Alibaba IDC senior technical expert Liu Shuiwang explains that data‑center battery management is more demanding than electric‑vehicle BMS because the batteries must deliver very high instantaneous power and meet strict reliability, safety, and longevity requirements.

Alibaba uses 12 V batteries that can directly power servers; the BBU adopts the same PSU interface protocol, allowing the existing server management platform to locate faulty BBUs and replace them quickly and accurately.

Since launching the 2011 Scorpion project and the 2017 global first immersion liquid‑cooling server cluster, Alibaba has continuously upgraded its data‑center technologies. The newly introduced lithium‑battery BBU server is expected to drive a new era of data‑center power supply and further transform the battery industry.