Epsilor Electric Fuel has developed lithium-ion batteries that stack to provide 1000 V in military systems, writes Nick Flaherty. The COMBATT Military High Voltage Battery System is based on Epsilor’s NATO standard 6T battery modules, it provides a capacity up to 175 Ah and 4400 Wh.

The COMBATT 6T batteries are currently undergoing the MIL-PRF-32565C US ARMY standardisation tests. These tests include bullet penetration, extreme temperature performance (up to 500 C) and long cycle life, ensuring reliability in the most demanding military environments. Both versions are designed to support defence vehicles, tactical energy storage applications and ground military robotics.

A variant of the battery, the COMBATT ELI-52526-GM, provides

4400 Wh/175 Ah capacity at 25.2 V for electric vehicles that are used in the field. This is six times the energy capacity of lead acid batteries of a similar weight, and 50% more than any other 6T lithium-ion battery pack. The connected strings of 6T battery modules are controlled by a joint high-voltage Battery Management System (BMS), which monitors and controls each individual 6T battery.

The cells are charged from a30 VDC power supply or 28 V alternator with a current of 82 A, although the BMS supports fast charging at 130A through a high current charge regulator that supports high-power alternator feed, surges and differential battery state of charge. The cells charge at temperatures between -40 C to 55 C using an internal heater with a discharge operation between -40 C to 71 C, again provided by the internal heater.

The battery packs can also be transported by air.