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2021-08-19

Lithium-ion Vehicle Batteries to Power the Future

In one form or another, batteries have existed for over 200 years. They have been used to power everything from modern phones to electric vehicle propulsion systems. Moreover, batteries are set to be the key enabler for future renewable energy sources. The demand for energy storage cells will only continue to grow with the increasing demand for electrical systems, particularly in the case of large-scale military platform applications.

The Lead Acid battery, invented by Gaston Planté in 1859, is commonly found in vehicles of today due to the economies of production. As the name suggests, Lead Acid batteries require acid: normally Sulfuric Acid (H₂SO₄) to produce a voltage, blended with distilled water and immersing lead plates. There are drawbacks with these batteries especially in a military environment.

Most military vehicles, when not on operations, spend long periods of time parked and unused, often in hot environments, which is not an ideal usage cycle for Lead Acid batteries. Battery shops within units are set up to store, service and maintain batteries, taking up valuable man-hours.

When inactive, the batteries suffer from de-sulphation/stratification if incorrectly managed and can require seven to 10 days to trickle charge in order to recover the battery. Often, the battery is unrecoverable and must be replaced, adding significant costs for the fleet manager.

Many military vehicles are built around a hull, a similar principle to a boat. Lead Acid batteries need ventilation to expel by-product gases i.e., poisonous hydrogen sulphide. They in turn lose acid levels and need to be topped up on a regular basis, particularly in hot conditions, as the batteries can ‘cook off’ their levels.

Even under ideal conditions, with regular maintenance, fluid top-ups and usage, Lead Acid batteries can have as little as 50 recharge cycles, and are often replaced every three months, ‘just to be safe’, meaning additional supplies, disposal, logistics, etc.

In comparison, the benefits of lithium type batteries are massive. They are maintenance free across a multi-year service lifespan with significantly less weight than a traditional Lead Acid battery.

Minimal Risk
Able to provide power for long periods, lithium-ion batteries are ideal in a silent watch scenario when the engine cannot be running for tactical reasons. In some cases, a one-hour charge can provide a full day of power, delivering the perfect power source for reconnaissance missions with minimal risk of being compromised and drastically reduced fuel consumption.

Galvion has developed a military optimised Li-ion battery, the Symbasys SwitchPack i6T Li-ion vehicle battery. From a user perspective, Galvion’s i6T battery offers considerable capability enhancements and through-life efficiencies. While the up-front cost cannot be compared to that of the traditional Lead Acid alternative; however, it is the cost over life that makes Li-ion the choice for the future.

The maintenance is free across a 10-year service lifespan, delivering as much as 8,000 recharge cycles; over twice that offered by any alternative 6T Li-ion unit. Compared to a traditional lead-acid 6T battery, Galvion’s SwitchPack delivers three times the useable capacity and energy at 24Volts (78Ah) and is 38 per cent lighter in weight. Because of the reliability, through-life cost savings are 87 per cent compared to lead-acid 6T alternatives and 43 per cent compared to other 6T Li-ion brands.

Galvion’s i6T Li-ion vehicle battery meets demanding military standards including MIL-STD-1275, MIL-STD-810 and the performance of MIL-PRF-32565, as well as stringent UN 38.3 commercial safety standards.

Some have questioned the auto shut down functionality of most lithium batteries given that most lithium batteries have a Battery Management System (BMS). To address this concern, Galvion have developed a battlefield override to squeeze every ounce of energy on a critical mission if required, in all battlefield temperature scenarios. The inclusion of a BMS allows the crew to better monitor power usage and remaining capacity, avoiding the surprises often associated with lead-acid batteries that have been allowed to run down a little too-far to restart the vehicle’s engine.

Despite the advantages offered when selecting Li-ion over Lead Acid, there are some integration challenges to ensure the new battery technology can be installed safely in a demanding military environment. Recent programmes with international partners included the design, manufacture, and delivery of ballistic enclosures to house the Li-Ion batteries. The custom-built enclosure, containing three i6T batteries for 234Ah, is mounted on or in vehicles with minimal vehicle modifications required.

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