Calendar life

The battery system has reached more than 1700 cycles in life cycle tests. The calendar life of the /zebra battery has been proven to be close to five years in a continuing life test. In practical operation in cars the ZEBRA battery exceeded 110000 km within a three year period. This excellent result proves the ZEBRA battery to be a reliable system. 

DIAGNOSTIC EVALUATION OF POWER FADE PHENOMENA AND CALENDAR LIFE REDUCTION IN HIGH-POWER LITHIUM-ION BATTERIES... 

In conclusion, KOH and NaOH activation is certainly able to provide activated carbons with the most adapted nanotextural characteristics for supercapacitors, at a reasonable cost. However, it must be pointed out that before to state definitively on the interest of these materials, long-term capacitor performance should be investigated. In order to fulfiU the practical demand, only carbons with a small RC constant, low leakage current, and limited self-discharge should be selected. The important research work which has been performed lately, especially by the companies developing supercapacitors, seems to indicate that impurities, even at a low level, or particular functional groups on carbon may strongly affect the calendar life of these devices. 

In the case of Ni-MH batteries, which can be cycled about 5000 times their nominal capacity at 80% DoD and more than 15,000 times their nominal capacity with shallow cycling [55,56,60-63], may be an appropriate choice. In the future, lithium-ion batteries may also enter the automotive market. Their high specific energy, which exceeds that of lead-acid systems by about a factor of three at medium discharge rates, would allow air-conditioning to be operated even in the engine-off mode. The calendar-life of lithium-ion batteries under automotive operating conditions, however, still needs to be improved, and there must be a reduction in cost to an acceptable level for such batteries. 

Lithium-ion [71-73] and lithium-ion polymer batteries [74] are commodity products in consumer applications, but are not yet ready for use in the harsh automotive environment. Although in an advanced state of development, the batteries are not expected to be ready for mass production for use in automotive applications in the near future. If limitations in calendar life at elevated temperature can be overcome and production costs can be lowered to an acceptable level, the lithium-ion battery may become a serious competitor to both AGM lead-acid and Ni-MH batteries, as the lithium-ion system combines the strengths of both these battery systems. 

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