Glossary & abbreviations

Ageing mechanism
Under normal conditions irreversible changes of components of the battery and its materials that eventually lead to a loss of performance.
Ah-throughput
Delivered charge (in Ah) in a defined period of time.
Category (of similar battery use)
A specified group of RES systems with typical operating characteristics and typical operating stress for batteries.
Charge factor
Ratio of the charged Ah to the discharged Ah in a defined period of time.
Charge efficiency (Ah-efficiency)
Ratio of discharged Ah to charged Ah in one charge/discharge cycle.
Energy efficiency (Wh-efficiency)
Ratio of discharged energy to charged energy in one charge/discharge cycle.
Equalisation voltage
A relatively high charging voltage that must be maintained only during a limited period of time. Charging at the equalization voltage brings all cells to the same state of charge and removes electrolyte stratification in flooded cells.
Float charging
Float charging is charging at a relatively low voltage. It is applied after a full battery charge at normal (bulk) charge.
Gassing
Production of oxygen and hydrogen gases at the positive and negative plates during (over)charging.
Recombination
Recombination of the oxygen and hydrogen produced by gassing inside a VRLA.
Reverse polarisation
Change of polarity (positive plates become negative and negative plates become positive), which is highly damaging.
Stress factor
A classification parameter used in the categorization process; the stress factors influence batteries ageing but do not in themselves lead to irreversible degradation of components of the battery.
Thermal runaway
The recombination of hydrogen and oxygen in a VRLA causes some increase in temperature. This increases the rate of gassing and recombination. At high gassing rate this self-accelerating effect may result in an overheated (ultimately exploded) battery.
Trickle charge
A charge at a low rate to maintain a cell or battery in a fully charged condition.
AGM Absorptive Glass Mat (for immobilizing the electrolyte in a LAB)
AM Active Mass
CN Nominal capacity related to the N hours rate discharge (IN)
DoD Depth of Discharge: discharged part (in %) of the battery capacity
(DoD = 100% - SoC)
I10 10 hours discharge current
(at which a battery is completely discharged in 10 hours)
Ix x hours discharge current
(at which a battery is completely discharged in x hours)
LAB Lead Acid Battery
NAM Negative Active Mass (AM of the negative electrode)
PAM Positive Active Mass (AM of the positive electrode)
PQ Power Quality
PSoC Partial State of Charge
RES Renewable Energy System
RESDAS http://www.ecn.nl/resdas/
Renewable Energy Systems Design Assistant for Storage
SoC State of Charge (SoC = 100% - DoD)
SLI car battery (Starting, Lighting and Ignition)
UPS Uninterruptible Power Supply.
VRLA Valve-Regulated Lead-Acid battery

 

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