Self-discharge is a phenomenon in batteries. Self-discharge decreases the shelf life of batteries and causes them to 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, charging current, ambient temperature and other factors. Primary batteries are not designed for recharging between manufacturing and use, and thus to be practical they must have much lower self-discharge rates than older types of secondary cells. Later, secondary cells with similar very low self-discharge rates were developed, like low-self-discharge nickel–metal hydride cells.
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 as a passivation layer develops on the electrodes over time.
Typical self-discharge by battery type
Battery chemistry Rechargeable Typical self-discharge or shelf life Lithium metal No 10 years shelf life Alkaline No 5 years shelf life Zinc–carbon No 2–3 years shelf life Thionyl chloride No 1% per yearMinamoto Data sheet of ER17505M Primary Lithium Thionyl Chloride 3.6V, 2800mAh, visited 19 November 2024 Lithium-ion Yes 2–3% per month; ca. 4% p.m.Umweltbundesamt: "BATTERIEN UND AKKUS" (3,65 MB PDF), October 2012; visited 2018-02-14 Lithium-polymer Yes ~5% per month Low self-discharge NiMH Yes As low as 0.25% per month Lead–acid Yes 4–6% per month Nickel–cadmium Yes 15–20% per month Conventional nickel–metal hydride (NiMH) Yes 30% per month
References
Further reading Wu and White, "Self-Discharge Model of a Nickel-Hydrogen Cell." Journal of the Electrochemical Society, 147 (3) 901-909 (2000)
External links Battery dischargers Description and treatment of sulphated batteries