Charge cycle is a characteristic value of rechargeable batteries. During this process, new energy is supplied to a discharged battery. A charge cycle or full cycle corresponds to the recharging of a discharged battery. After discharging, the battery is recharged up to the permissible discharge limit until it is fully charged again. The full charge corresponds to the State of Charge( SoC) of 100%.
If a battery is recharged from a 50% level, this is half a charge cycle. A charge cycle is only reached when a 50 % value is charged twice. The number of charge cycles always assumes the same number of discharge cycles. The characteristic value of charge cycles is very much dependent on the battery type, but also on the type of use and thus on various other factors. Important factors are the discharge current, the discharge time and the depth of discharge ( DoD), another factor related to the discharge current is the temperature. These two factors significantly affect the number of charge cycles.
For the common rechargeable batteries used in electric vehicles and mobile devices, depending on the state of charge, the number of charge cycles for lead-acid batteries is given as about 3,000, that for NiCd batteries as 10,000, and that for lithium-ion batteries as many as one thousand. As for electric vehicle batteries, the values for charging cycles range from 500 to 1,000 charging cycles. After batteries have been charged with the specified number of charging cycles, the storage capacity of the batteries decreases. The values specified by the manufacturer are only achieved under the specified operating conditions and proper care. For mobile device manufacturers, the realistic values are lower by a power of ten.
Unlike rechargeable batteries, supercapacitors and double- layer capacitors are characterized by an almost unlimited cycle stability of several hundred thousand charge cycles.