Saft develops Li-ion battery for military applications

This post was originally published on this site

Saft’s Xcelion 56V-LEV Li-ion battery offers a high-capacity, low-weight replacement for lead-acid batteries in military applications

By Gina Roos, editor-in-chief, Electronic Products

Saft America’s latest addition to the Xcelion battery line, a 56-V low-rate energy lithium-ion (Li-ion) battery, delivers right-sized configurations for 48-V continuous cycling applications that require lower current. The Xcelion 56V-LEV battery was designed as a more economical option for these applications, particularly in the defense industry. The new battery can be used in uninterruptible power supply (UPS) applications for military, defense ground stations, electric mobility, and backup power storage.

“The biggest challenge [in the military] is finding the right battery that meets all of the requirements at the right price,” said Scott Ferguson, Saft’s Xcelion global product manager. “There is a growing tendency to try to find an off-the-shelf solution, so there is sometimes compromise in terms of expected performance or cost in order to adopt an available battery solution.”

Saft-military

The Xcelion 56V-LEV batteries offer a high-capacity and low-weight replacement for traditional lead-acid batteries, which the military is looking to replace to enable additional functionality and to extend battery life. The 41-Ah Li-ion battery is a commercial off-the-shelf solution with a nominal voltage of 52.8 V.

“Lead-acid systems are limiting in deep-cycle capability and will wear out much faster when used in these applications,” said Ferguson. “While a lithium-ion solution is likely more expensive up front, it saves cost overall due to lower frequency of replacements and reduced maintenance. Additionally, the deep cycling offered with lithium solutions enables longer reliable silent watch and overall mission capability.”

Building on the original Xcelion 6T battery launched in 2015, the Xcelion 56V-LEV battery, the sixth in the Xcelion line, focuses on offering lower weight, longer life, and greater overall capability compared to lead-acid batteries. It offers a “more streamlined design for applications that require continuous cycling and don’t need the cranking power required of vehicle applications addressed by the Xcelion 6T,” said Saft.

Ferguson said that the original Xcelion 6T is a great off-the-shelf solution for replacing lead-acid batteries for military vehicles, providing the high current needed for engine start and other high-power demands.

However, many customers have started to adopt this battery for other applications in which the high rates are not required, leading to the new design.

“The LEV is a spinoff product to meet those applications requiring low rates,” Ferguson added. “With the reduction in power capability comes a simplification of the internal battery design and the complex power electronics. This reduces the cost of the product.”

The 56V-LEV also includes the same Xcelion family standard safety features, such as the abuse-tolerant Super-Phosphate Li-ion technology and battery management system (BMS). Unlike lead-acid batteries, smart battery features enable communication with the end user, which provides information about the battery state of health, state of charge, and other functions.

“The main advantage of the Super-Phosphate lithium-ion chemistry is the safety,” said Ferguson. “The cells are far less reactive, so when subjected to destructive abuse, they are much safer to the user and far less likely to go into a thermal runaway situation seen with typical lithium-ion chemistry.”

The chemistry also delivers other unique performance advantages over traditional lithium-ion. “The resistance of the battery is much more stable over its life, so the power capability of an aged battery is nearly the same as a new battery,” Ferguson added. “This extends the useful life of the battery in most applications.”

The BMS monitors the cell currents, voltages, and temperatures to ensure that they are operating within specification and includes an interface so that the user can communicate with the battery to continuously observe the state of charge, state of health, and other key performance features. The safety system also monitors the state of the BMS and looks for any overtemperature, and it includes built-in test functionality to continuously ensure that the BMS is operating properly.

“In the event that a fault is detected in the cells or the BMS, the battery will disable the terminals, preventing further charge or discharge of the battery that could lead to further off-spec conditions,” said Ferguson.

Saft has also launched the Xcelion 6T-E for applications requiring longer runtimes (e.g., silent watch missions on military vehicles), the Xcelion 56V for higher-voltage applications (which is available in both power and energy versions), and the Xcelion 6T Type 1-A that is designed to meet MIL-PRF-32565 Rev B and provides cold cranking performance and safety.