Self-discharge
Encyclopedia
Self-discharge is a phenomenon in batteries
in which internal chemical reactions reduce the stored charge of the battery without any connection between the electrodes. Self-discharge decreases the shelf-life of batteries and causes them to initially have less than a full charge when actually put to use.
How fast self-discharge in a battery occurs is dependent on the type of battery, state of charge, ambient temperature and other factors. Typically, among rechargeable batteries, lithium batteries suffer the least amount of self-discharge (around 2–3% discharge per month), while nickel
-based batteries are more seriously affected by the phenomenon (nickel cadmium, 15–20% per month; nickel metal hydride, 30% per month), with the exception of Low self-discharge NiMH batteries (2-3% per month).
Primary batteries, which cannot be recharged between manufacturing and use, have much lower self-discharge rates.
Self-discharge is a chemical reaction, just as closed-circuit discharge is, and tends to occur more quickly at higher temperatures. Storing batteries at lower temperatures thus reduces the rate of self-discharge and preserves the initial energy stored in the battery. Self-discharge is also thought to be reduced over time as a passivation layer develops on the electrodes.
The detailed chemical causes of self-discharge depend on the particular battery and are not well understood.
Battery (electricity)
An electrical battery is one or more electrochemical cells that convert stored chemical energy into electrical energy. Since the invention of the first battery in 1800 by Alessandro Volta and especially since the technically improved Daniell cell in 1836, batteries have become a common power...
in which internal chemical reactions reduce the stored charge of the battery without any connection between the electrodes. Self-discharge decreases the shelf-life of batteries and causes them to initially have less than a full charge when actually put to use.
How fast self-discharge in a battery occurs is dependent on the type of battery, state of charge, ambient temperature and other factors. Typically, among rechargeable batteries, lithium batteries suffer the least amount of self-discharge (around 2–3% discharge per month), while nickel
Nickel
Nickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...
-based batteries are more seriously affected by the phenomenon (nickel cadmium, 15–20% per month; nickel metal hydride, 30% per month), with the exception of Low self-discharge NiMH batteries (2-3% per month).
Primary batteries, which cannot be recharged between manufacturing and use, have much lower self-discharge rates.
Self-discharge is a chemical reaction, just as closed-circuit discharge is, and tends to occur more quickly at higher temperatures. Storing batteries at lower temperatures thus reduces the rate of self-discharge and preserves the initial energy stored in the battery. Self-discharge is also thought to be reduced over time as a passivation layer develops on the electrodes.
The detailed chemical causes of self-discharge depend on the particular battery and are not well understood.