By: Michael Vest, Sr. Product Manager North America at HOPPECKE Batteries

Sealed lead acid batteries have been used in numerous applications since the 1850s and remain in use today.

Recently lithium batteries (Li-ion) have been touted as the newest technology for data centers over the proven lead acid solutions. While there are promising improvements in lithium, such as high-power density and reduced weight, the data center market should consider alternate options and should understand the Total Cost of ownership (TCO) in their selection of battery technology.

Environmental and Labor Concerns

There are numerous Lithium (Li-ion) battery electro chemistries. LMO and NMC are two common types of Li-ion. NMC batteries naturally contain nickel, manganese, and cobalt with varying ration of three materials in the final product. LMO batteries replace cobalt with manganese.

China produced nearly seven million metric tons of manganese in the recent year, showing an increase of around one million tons from the previous year. China leads in manganese mining in Asia. The Democratic Republic of Congo is known for being the primary exporter of cobalt, despite reports of child labor and unsafe working conditions. In the Ades region which covers Argentina, Chile, and Bolivia, there is another significant source of lithium. Environmentalists are concerned about potential threats to essential water resources in these mining areas.

Cost

VRLA batteries are generally more cost-effective than lithium-ion batteries, with potential savings ranging from hundreds to thousands of dollars for systems of similar sizes.

It’s important to note that the cost of Battery Management Systems (BMS) can vary, and opting for VRLA batteries can result in significant cost savings. Li-ion for data centers is required to have a BMS in place to prevent thermal runaway and other potential safety issues. Additionally, they require additional electronic protection such as automatic breakers and fuses. With these additional Li-ion costs the cost of VRLA batteries can be up to 30-40% less when considering the net present value of money assuming a 4%-6% per year inflation rate while including the life expectancy of the cells.

For these reasons, data centers have long favored VRLA batteries because of their established dependability and inexpensive initial purchase cost.

China dominates the global lithium-ion battery market, producing 80 to 90 percent or more of some key components and minerals.

In May 2024, the Biden administration announced that it would more than triple tariffs on batteries and battery components imported into the United States from China, from 7.5% to 25%. The battery energy storage system (BESS) manufacturers will be given two more years to purchase U.S.-made cells to protect themselves from a new 25% tariff in 2026.

Aside from their initial cost, Li-ion batteries fall under the hazardous material category (Class 9) as defined by the Hazardous Materials Regulations (HMR) of the United States Department of Transportation (DOT). This regulation (UN 38.3) pertains to substances considered by the DOT to present an unacceptable risk to human health, safety, or property during transportation for commercial purposes. Li-Ion batteries cannot be shipped at a greater charge than 50% presently. This additional cost for packaging, labeling, transportation, and storage compliance to UN38 is frequently overlooked.

Performance-Reliability and TCO

Lead acid batteries have been used for decades and have a proven track record of reliability. The U.S. Department of Energy (DOE) just awarded 5 million dollars to the Battery Council International (BCI) to support long-duration energy storage research in collaboration with national labs.

Marketing materials claim that Lithium batteries perform better in higher temperatures. However, unlike typical lead batteries, some new pure lead batteries as the HOPPECKE “Xtreme” battery series is designed to operate at temperatures up to 55C (131F).

Today’s pure lead batteries have a low operating temperature of -40°F (-40°C) which is well below most Li-ion capabilities. According to numerous sources, Li-ion batteries will not accept a charge at low temperatures (below 32 °F) which is a rare occurrence in a data center environment.

Lithium batteries have not had the proven usage to support the claims above. The BMS required on all lithium batteries is critical to the safe operation of the battery. The BMS can be prone to failure and the cost of updating software is not typically considered. In contrast, Lead-acid batteries do not need ancillary equipment to function.

Safety

Li-ion battery fires can be classified as chemical fires as they do not rely on oxygen to burn.

While they do not emit gas during normal use, Copious amounts of hazardous gases are emitted during a thermal runway condition. Li-ion fires are self-sustaining as they create oxygen which feeds the fire. Therefore, this means that a lithium battery fire can only be cooled and allowed to burn down in a controlled manner.

Li-ion batteries require special fire extinguishers (Class B), so care should be used, and training should be completed to assure workplace safety. It’s for this reason that fire regulations and insurance companies require strict safety precautions when installing and storing.

Li-ion batteries used in the industrial world have what is known as a Battery Monitoring System (BMS). The BMS itself is assessable to failure. They are required and play a critical role to ensure both safety and accuracy. Its role is to:

  • Measure voltage, temperature, and current values
  • Protect based on the measured values
  • Manage and diagnose the state of charge (SOC)
  • Relay the status back to a smart charger

Maintenance

Lead acid batteries require minimal maintenance compared to Li-ion batteries, which can require special charging equipment and temperature monitoring.

The primary concern regarding the overheating of Li-ion batteries is a phenomenon called thermal runaway. This occurrence involves the escalation of heat-triggering chemical reactions within the battery, leading to a cycle of increased heat generation and further chemical reactions, resulting in a catastrophic chain reaction.

To avoid this, the chargers must shut off or the battery’s BMS must operate open which could lead to a service outage.

The skilled labor required to install a lithium cell vs a lead acid battery is much less common. In addition, the BMS is sometimes warranted less than the system components. The BMS might also need to be updated as needed or risk voiding the system warranty.

Footprint

A common misconception is that Lithium batteries have a smaller footprint than lead-acid. Normally this would be correct, however, now exist new solutions for data centers that eliminates these concerns by offering a modular design and keeps the batteries stored upright and without gaps, keeping the footprint low and making the installations and commissioning easy.

Summary

Sealed lead-acid batteries have been a reliable choice for various applications since the 1850s. Recently, lithium-ion batteries have emerged as a newer technology for data centers, offering advantages like higher power density and reduced weight. However, data centers must consider the Total Cost of Ownership (TCO) when choosing between lead-acid and lithium batteries.

Key Differences:

  • Cost: Lead-acid batteries are generally more cost-effective than lithium-ion batteries, with significant savings due to lower initial costs and reduced need for Battery Management Systems (BMS). Lithium-ion batteries require additional safety measures and electronic protection, raising their overall cost.
  • Environmental and Labor Concerns: Lithium-ion batteries involve complex chemistries and raise environmental and labor issues, particularly related to cobalt and manganese mining. This includes concerns about child labor and environmental impacts in mining regions.
  • Performance and Reliability: Lead-acid batteries have a proven track record and require minimal maintenance compared to lithium-ion batteries, which have higher operational and maintenance demands. Lithium-ion batteries are also more susceptible to thermal runaway and require careful management.
  • Safety: Lithium-ion batteries pose unique safety risks, including hazardous fires that require special extinguishing methods and strict safety protocols. Lead-acid batteries, in contrast, are generally safer and simpler to manage.
  • Footprint: While lithium-ion batteries are often thought to have a smaller footprint, recent innovations like HOPPECKE’s modular designs have made lead-acid battery installations more compact and efficient.

In conclusion, while lithium-ion batteries offer some technological advancements, lead-acid batteries remain a dependable and cost-effective option for many data centers. Evaluating factors such as cost, environmental impact, performance, and safety is crucial in choosing the right battery technology.

Learn more about HOPPECKE’s Xtreme Batteries here.

Learn more about HOPPECKE’s Xtreme Stack here.

About the Author

Michael Vest is a seasoned professional in the power industry, boasting an impressive 40-year career marked by a wealth of experience across various prestigious companies. He spent 25 years at Lucent Technologies, Bell Labs, and Lineage Power, where he excelled in numerous roles, including Technical Support and Product Management, contributing significantly to the development and enhancement of power solutions.

Currently, He serves as the Director of Product Management for HOPPECKE Batteries in the U.S. market, leveraging his extensive background to drive innovation and enhance product offerings.