Self-discharge

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search

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 or any external circuit.[1] Self-discharge decreases the shelf life of batteries and causes them to have less than a full charge when actually put to use.[1]

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.[2] Primary batteries are not designed for recharging between manufacturing and use, thus have battery chemistry that has to have a much lower self-discharge rate than older types of secondary cells, but have lost that advantage with the development of rechargeable secondary cells with very low self discharge rates like NiMH 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[edit]

Battery chemistry Rechargeable Typical self-discharge or shelf life
Lithium metal No 10 years shelf life[3]
Alkaline No 5 years shelf life[3]
Zinc–carbon No 2–3 years shelf life[3]
Lithium-ion Yes 2–3% per month;[3] ca. 4% p.m.[4]
Lithium-polymer Yes ~5% per month[5][better source needed]
Low self-discharge NiMH Yes As low as 0.25% per month[6]
Lead–acid Yes 4–6% per month[3]
Nickel–cadmium Yes 15–20% per month[3]
Nickel–metal hydride (NiMH) Yes 30% per month[3]

References[edit]

  1. ^ a b Garche, Jurgen; Dyer, Chris K.; Moseley, Patrick T.; Ogumi, Zempachi; Rand, David A. J.; Scrosati, Bruno (2013). Encyclopedia of Electrochemical Power Sources. Newnes. p. 407. ISBN 978-0-444-52745-5.
  2. ^ Moseley, Patrick T.; Garche, Jurgen (27 October 2014). Electrochemical Energy Storage for Renewable Sources and Grid Balancing. Newnes. pp. 440, 441. ISBN 9780444626103.
  3. ^ a b c d e f g Battery performance characteristics, MPower UK, 23 February 2007. Information on self-discharge characteristics of battery types
  4. ^ Umweltbundesamt: "BATTERIEN UND AKKUS" (3,65 MB PDF), October 2012; visited 2018-02-14
  5. ^ "Lithium Polymer Battery Technology" (PDF). Retrieved 14 March 2016.
  6. ^ Panasonic

Further reading[edit]

External links[edit]