Saft batteries to power Land Warrior

Saft batteries will power Land Warrior, the US Army's computerised soldier of the future.

High performance, compact format MP series prismatic lithium-ion rechargeable batteries will play key role in success of computerised integrated fighting system Battery power rather than fire-power could be the vital factor in the combat success of Land Warrior, the US Army's six billion dollar computerised integrated fighting system for the dismounted infantryman.

So to keep all the vital electronic equipment operating at maximum power for a typical eight hour mission each soldier will carry a Saft high performance, lightweight rechargeable lithium-ion battery pack.

Land Warrior is being developed by Project Manager - Soldier (PM-Soldier) of the US Army Soldier and Biological Chemical Command (SBCCOM) to provide everything a combat soldier needs: a helmet, a weapon, a backpack, and a computer/radio, in a fully integrated system.

According to Colonel Hank Kinnison, Training and Doctrine Command's systems manager for soldiers at Fort Benning, GA, Land Warrior is being built for "the rifle squad in close contact at two o'clock in the morning, in a driving rain storm with a stubborn enemy shooting back and rapidly moving against their positions.

The goal is to enable the squad to "see that enemy more clearly, to see the battlefield more clearly, so that the platoon can get an advantage on its opponent.

Land Warrior systems/components include: a modular weapon system with thermal weapon sight, laser range-finder, digital compass, and daylight video camera; day and night heads-up display of computer and sensor inputs; night vision capability; protective clothing and individual equipment enhancements; an individual soldier computer/radio.

The systems approach is designed to optimise and integrate these capabilities, without adding to the soldier's combat load.

The integrated squad and soldier radios together with the Global Positioning System (GPS) will provide the soldier's location to the computer, integrate it with location reports from other soldiers, known enemy locations and map graphics and display the information on a digital map on the heads-up display In order to power the Land Warrior systems, PM-Soldier tasked the US Army Communications - Electronics Command (CECOM) to develop rechargeable and disposable batteries.

CECOM required a high power battery pack that would not only last a full mission without replacement, it also had to be rugged, lightweight and capable of operating in all climates from the heat of the desert to the Arctic winter.

This specification proved so demanding that Saft America was the only manufacturer to provide a rapid response to the initial enquiry.

The battery packs which Saft is providing to Computer Sciences Corp, a main contractor for Land Warrior, are based on the company's high performance, compact format MP series prismatic Li-ion cells.

These are used typically in a host of portable and standby applications such as rugged computers, video and camcorders and medical equipment as well as by many existing military radio communications customers.

A key advantage of the MP cell is its unique rectangular shape which gives it an extremely high capacity by utilising the volume lost when conventional cylindrical cells are packed together - a single prismatic cell has some 20 per cent higher volumetric energy density than an equivalent pack of cylindrical cells.

Saft's lithium-ion electrochemistry uses a graphite negative electrode and lithiated cobalt oxide positive electrode.

Operating temperatures range from -30°C to +60°C (in discharge) while another vital factor for military usage is that the cell will still retain 95 per cent of its charge after one month's storage.

The MP cells also offer a long service life and will retain 85 per cent of their initial capacity after 500 charge-discharge cycles, and 75 per cent after 1000 cycles.

The specific cell used for Land Warrior is the largest in the MP range, the MP176065, which offers a nominal voltage of 3.6 V and a capacity of 5.5 Ah.

Following the success of Saft's initial prototype batteries in powering Land Warrior systems for preliminary testing and debugging CECOM recently authorised the purchase of 500 Li-ion battery packs and chargers for use in field trials, including 'jump certification' by paratroops.

These battery packs comprise eight MP cells, in four series by two parallel configuration, giving an 11 Ah capacity.

They are being supplied in a ruggedized, water resistant metal housing complete with protection circuitry, state of charge indicator and a commercial off the shelf connector.

Although rechargeable batteries will be used in Land Warrior, CECOM anticipates there will be some situations where recharging is not feasible.

In this case the soldier will simply swap the rechargeable pack for a disposable primary battery pack.

A six-page colour datasheet detailing Saft's MP cells is available from Sylvie Dewuite, Saft, 156 avenue de Metz, 93230 Romainville, FRANCE (tel: +33 (0) 1 49.15.34.61 fax: +33 (0) 1 49.15.36.24 e-mail: sylvie.dewuite@saft.alcatel,fr.

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