GLOSSARY OF TERMS FOR SEALED LEAD-ACID BATTERIES - CONTINUED
NOMINAL VOLTAGE A nominal value to indicate the voltage of a cell battery. Generally, nominal voltage value of a battery is somewhat lower than its electromotive force. Nominal voltage of the lead-acid battery is 2.0 V per unit cell.
OPEN CIRCUIT VOLTAGE Measured voltage of a cell/battery which is electrically disconnected from the external circuit.
Continued charging of a fully charged cell/battery. With batteries which require watering, overcharge causes electrolysis of water, resulting in rapid decrease of electrolyte. Generally, overcharge adversely influences battery life.
OVERDISCHARGE Discharge of a battery to a voltage below a predetermined cut-off voltage.
PARALLEL CHARGE Simultaneous charging of two or more batteries connected in parallel. In cyclic use of batteries, specifically, the parallel charge tends to cause an imbalance in charge state among the batteries, which may shorten their service life.
POLYPROPYLENE RESIN A plastic material which is often used for the case and cover of batteries.
The battery electrode from which a current flows to the external circuit during discharging. The positive plate has higher electric potential than the negative plate to the electrolyte. The positive plate is incorporated with connection parts such as the electrode pole.
QUICK CHARGE (RAPID CHARGE) Charging in a short time with a large current.
RATED CAPACITY The stated capacity of a battery; namely, the ampere- hour amount which can be drawn from the battery in fully charged state at a specified temperature, at a specified discharge rate, and to a specified cut-off voltage. The symbol CN may be used to express the rated capacity of N-hour rate.
RECHARGEABLE BATTERY The rechargeable battery is a system comprising two different electrodes and an ion-conductive medium, which is capable of converting chemical energy to electric energy, and vice versa. It is also called a secondary battery.
REFRESH CHARGE (AUXILIARY CHARGE) Charging of a battery mainly to compensate for its self discharge.
RESIDUAL CAPACITY Residual capacity of a battery after partial discharge or after storage for long time.
A method to control flowing electrolyte in a battery with the retainer mat, etc..
REVERSE CHARGE Charging of a battery with its polarity reversed. Namely, the battery discharges.
SELF DISCHARGE Reduction in capacity of a battery while no current is drawn by the external circuit. Self discharge depends on temperature: amount of discharge approximately
doubles by each
(10C) rise of ambient temperature.
SEALED LEAD-ACID BATTERY (SLA
BATTERY) Valve-regulated lead-acid battery.
A porous or microporous liquid-absorbent material which is installed between the battery electrodes for preventing short-circuit, securing the separation of the electrodes and retaining electrolyte. The separator should be resistant to oxidation and chemicals; it should excel in electric insulation and liquid-retention; and it should not disturb diffusion of the electrolyte and ionic conduction.
Sealed Lead-Acid Handbook, Page 75