Performance Boost for Li-ion Cells
15 December 2005 09:34
Saft has upgraded the performance of all three cell sizes in its MP series of prismatic rechargeable lithium-ion batteries.
In addition to a significant increase in capacity - providing extra autonomy between charges for a wide variety of professional and military electronic equipment - the upgraded MP cells also offer a higher maximum end of charge voltage and a wider operating temperature range.
As a result of the upgrade, the largest MP cell, the MP 176065, has benefited from a 17 per cent increase in nominal capacity from 5.8Ah to 6.8Ah. The intermediate MP 174865 cell has a 15 per cent capacity increase, from 4.6Ah to 5.3Ah. And the small MP 144350 has increased in capacity by 13 per cent, from 2.3Ah to 2.6Ah.
To enable users to make full use of this increased capacity, the maximum end of charge voltage for all MP cells has been increased to allow charging up to 4.2V. However, the previous maximum voltage of 4.1V can still be retained for legacy applications where charge settings cannot be modified.
The upgraded MP series offers the same discharge current capability as the existing cells, but over a wider temperature range. Discharge in cold conditions is now possible down to -50°C, at a continuous rate recommended not to exceed C/5. In temperatures from 0°C to +60°C, continuous discharges up to 2C, with current pulses up to 4C, can now be safely achieved.
Furthermore, charging (at rates up to C) is now possible down to -20°C, compared with 0°C previously.
The extremely high capacity of the MP cells is made possible by the stainless steel prismatic container that makes use of the volume lost when conventional cylindrical cells are packed together. Saft's lithium-ion electrochemistry uses cobalt-base and graphite active materials, combined with an innovative organic solvent mix for the electrolyte.
Saft MP cells are completely maintenance free, and hermetically sealed at temperatures up to +75°C. And, in addition to the electronic protection circuits that monitor individual cells within battery packs, the upgraded MP cells continue to benefit from such well-proven safety features as: built-in circuit breakers (that enable the fast, automatic disconnection of cells from faulty chargers); safety vent (operating when cell internal pressure exceeds 12-15 bars); a shut down separator (with pores that automatically get clogged in case of accidental short-circuit).
Saft has designed the MP cells to withstand the most common field abuses, such as mechanical shock and vibration, as well as external short-circuit, crushing, nail piercing and so on.
The MP concept is designed to provide the basic building block for the vast array of rechargeable batteries required by modern military and professional applications. Pack assembly costs are reduced and reliability increased because cell-to-cell wiring is reduced or, for many applications, eliminated completely. MP cells are ideally suited for ruggedised designs, and integrate readily into compact and light systems.
For more information on this company:
Saft - Lithium Cells and Battery Packs
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