Depth of discharge (DoD) is an important parameter appearing in the context of rechargeable battery operation. Two non-identical definitions can be found in commercial and scientific sources. The depth of discharge is defined as:
the maximum fraction of a battery's capacity (given in Ah) which is removed from the charged battery on a regular basis.[1][2][3][4] "Charged" does not necessarily refer to fully or 100% charged, but rather to the state of charge (SoC), where the battery charger stops charging, which is achieved by different techniques.
the fraction of the battery's capacity which is currently removed from the battery with regard to its (fully) charged state. For fully charged batteries, the depth of discharge is connected to the state of charge by the simple formula . The depth of discharge then is the complement of state of charge: as one increases, the other decreases. This definition is mostly found in scientific sources.[5][6][7][8][9]
The depth of discharge can therefore (1) refer to the size of the range usually used for discharge or (2) the current amount of charge or fraction of the capacity removed from the battery. To avoid confusion, the exact meaning of DoD should be clear for a given context. Also, for both definitions, it remains undefined, whether a charged battery's SoC is 100 % or another value. This reference value is needed to fully describe (1) the upper and lower limit of absolute SoC used for operation or (2) the current value of the absolute SoC.
During their use, secondary batteries are repeatedly charged and discharged within a certain range of state of charge. For many battery types, it is beneficial or even mandatory for safety reasons, to not encounter overcharging and/or deep discharge. To prevent adverse effects, a battery management system or battery charger may keep the battery from extreme levels regarding SoC, thereby limiting the SoC to a reduced range between 0 % and 100 % and decreasing depth of discharge below 100 % (see example below). This corresponds to the DoD in the sense of definition (1).
For almost all known rechargeable battery technologies, such as lead-acid batteries of all kinds like AGM, there is a correlation between the depth of discharge and the cycle life of the battery.[10] For LiFePO 4 batteries, for example, the state of charge is often limited to the range between 15 % and 85 % to greatly increase their cycle life, resulting in a DoD of 70 %.[3]
While the state of charge is usually expressed using percentage points (0 % = empty; 100 % = full), depth of discharge is either expressed using units of Ah (e.g. for a 50 Ah battery, 0 Ah is full and 50 Ah is empty) or percentage points (100 % is empty and 0 % is full). The capacity of a battery may also be higher than its nominal rating. Thus it is possible for the depth of discharge value to exceed the nominal value (e.g., 55 Ah for a 50 Ah battery, or 110 %).
Sample calculationedit
Using definition (2), the depth of discharge of a charged 90 Ah battery is discharged for 20 minutes at a constant current of 50 A is calculated by:
Deep dischargeedit
This section needs expansion. You can help by adding to it. (August 2023)
^Bhadra, Shoham; Hertzberg, Benjamin J.; Hsieh, Andrew G.; Croft, Mark; Gallaway, Joshua W.; Van Tassell, Barry J.; Chamoun, Mylad; Erdonmez, Can; Zhong, Zhong; Sholklapper, Tal; Steingart, Daniel A. (2015). "The relationship between coefficient of restitution and state of charge of zinc alkaline primary LR6 batteries" (PDF). Journal of Materials Chemistry A. 3 (18): 9395–9400. doi:10.1039/C5TA01576F. OSTI 1183288.
^Wang, John; Liu, Ping; Hicks-Garner, Jocelyn; Sherman, Elena; Soukiazian, Souren; Verbrugge, Mark; Tataria, Harshad; Musser, James; Finamore, Peter (2011-04-15). "Cycle-life model for graphite-LiFePO4 cells". Journal of Power Sources. 196 (8): 3942–3948. Bibcode:2011JPS...196.3942W. doi:10.1016/j.jpowsour.2010.11.134. ISSN 0378-7753.
^Yamamoto, Takahiko; Ando, Tomohiro; Kawabe, Yusuke; Fukuma, Takeshi; Enomoto, Hiroshi; Nishijima, Yoshiaki; Matsui, Yoshihiko; Kanamura, Kiyoshi; Takahashi, Yasufumi (2021-11-02). "Characterization of the Depth of Discharge-Dependent Charge Transfer Resistance of a Single LiFePO4 Particle". Analytical Chemistry. 93 (43): 14448–14453. doi:10.1021/acs.analchem.1c02851. ISSN 0003-2700. PMID 34668693.
^Shim, Joongpyo; Striebel, Kathryn A. (2003-06-01). "Cycling performance of low-cost lithium ion batteries with natural graphite and LiFePO4". Journal of Power Sources. Selected papers presented at the 11th International Meeting on Lithium Batteries. 119–121: 955–958. Bibcode:2003JPS...119..955S. doi:10.1016/S0378-7753(03)00297-0. ISSN 0378-7753. S2CID 53992561.
^Anseán, D.; Viera, J. C.; González, M.; García, V. M.; Álvarez, J. C.; Antuña, J. L. (2013). "High power LiFePO4 cell evaluation: Fast charge, Depth of Discharge and Fast discharge dependency". World Electric Vehicle Journal. 6 (3): 653–662. doi:10.3390/wevj6030653. ISSN 2032-6653.
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Depth of discharge DoD is an important parameter appearing in the context of rechargeable battery operation Two non identical definitions can be found in commercial and scientific sources The depth of discharge is defined as the maximum fraction of a battery s capacity given in Ah which is removed from the charged battery on a regular basis 1 2 3 4 Charged does not necessarily refer to fully or 100 charged but rather to the state of charge SoC where the battery charger stops charging which is achieved by different techniques the fraction of the battery s capacity which is currently removed from the battery with regard to its fully charged state For fully charged batteries the depth of discharge is connected to the state of charge by the simple formula DoD 1 SoC displaystyle mathrm DoD 1 mathrm SoC The depth of discharge then is the complement of state of charge as one increases the other decreases This definition is mostly found in scientific sources 5 6 7 8 9 The depth of discharge can therefore 1 refer to the size of the range usually used for discharge or 2 the current amount of charge or fraction of the capacity removed from the battery To avoid confusion the exact meaning of DoD should be clear for a given context Also for both definitions it remains undefined whether a charged battery s SoC is 100 or another value This reference value is needed to fully describe 1 the upper and lower limit of absolute SoC used for operation or 2 the current value of the absolute SoC Contents 1 Occurrence 2 Sample calculation 3 Deep discharge 4 See also 5 ReferencesOccurrence editDuring their use secondary batteries are repeatedly charged and discharged within a certain range of state of charge For many battery types it is beneficial or even mandatory for safety reasons to not encounter overcharging and or deep discharge To prevent adverse effects a battery management system or battery charger may keep the battery from extreme levels regarding SoC thereby limiting the SoC to a reduced range between 0 and 100 and decreasing depth of discharge below 100 see example below This corresponds to the DoD in the sense of definition 1 For almost all known rechargeable battery technologies such as lead acid batteries of all kinds like AGM there is a correlation between the depth of discharge and the cycle life of the battery 10 For LiFePO4 batteries for example the state of charge is often limited to the range between 15 and 85 to greatly increase their cycle life resulting in a DoD of 70 3 While the state of charge is usually expressed using percentage points 0 empty 100 full depth of discharge is either expressed using units of Ah e g for a 50 Ah battery 0 Ah is full and 50 Ah is empty or percentage points 100 is empty and 0 is full The capacity of a battery may also be higher than its nominal rating Thus it is possible for the depth of discharge value to exceed the nominal value e g 55 Ah for a 50 Ah battery or 110 Sample calculation editUsing definition 2 the depth of discharge of a charged 90 Ah battery is discharged for 20 minutes at a constant current of 50 A is calculated by DoD 50 A 20 mins60 mins hours90 Ah 100 18 522 displaystyle mathrm DoD frac 50 text A cdot frac 20 text mins 60 text mins text hours 90 text Ah cdot 100 18 522 nbsp Deep discharge editThis section needs expansion You can help by adding to it August 2023 See also editBattery balancing Smart battery Deep cycle battery State of healthReferences edit Cheng Yu Shan Liu Yi Hua Hesse Holger C Naumann Maik Truong Cong Nam Jossen Andreas 2018 A PSO Optimized Fuzzy Logic Control Based Charging Method for Individual Household Battery Storage Systems within a Community Energies 11 2 469 doi 10 3390 en11020469 ISSN 1996 1073 Wikner Evelina Thiringer Torbjorn 2018 Extending Battery Lifetime by Avoiding High SOC Applied Sciences 8 10 1825 doi 10 3390 app8101825 ISSN 2076 3417 a b gwl power lithium amp solar power LiFePO4 lithium amp solar power LiFePO4 Retrieved 2022 02 20 Blog LiFePO4 shop GWL eu shop gwl eu Retrieved 2022 02 20 Bhadra Shoham Hertzberg Benjamin J Hsieh Andrew G Croft Mark Gallaway Joshua W Van Tassell Barry J Chamoun Mylad Erdonmez Can Zhong Zhong Sholklapper Tal Steingart Daniel A 2015 The relationship between coefficient of restitution and state of charge of zinc alkaline primary LR6 batteries PDF Journal of Materials Chemistry A 3 18 9395 9400 doi 10 1039 C5TA01576F OSTI 1183288 Wang John Liu Ping Hicks Garner Jocelyn Sherman Elena Soukiazian Souren Verbrugge Mark Tataria Harshad Musser James Finamore Peter 2011 04 15 Cycle life model for graphite LiFePO4 cells Journal of Power Sources 196 8 3942 3948 Bibcode 2011JPS 196 3942W doi 10 1016 j jpowsour 2010 11 134 ISSN 0378 7753 Yamamoto Takahiko Ando Tomohiro Kawabe Yusuke Fukuma Takeshi Enomoto Hiroshi Nishijima Yoshiaki Matsui Yoshihiko Kanamura Kiyoshi Takahashi Yasufumi 2021 11 02 Characterization of the Depth of Discharge Dependent Charge Transfer Resistance of a Single LiFePO4 Particle Analytical Chemistry 93 43 14448 14453 doi 10 1021 acs analchem 1c02851 ISSN 0003 2700 PMID 34668693 Shim Joongpyo Striebel Kathryn A 2003 06 01 Cycling performance of low cost lithium ion batteries with natural graphite and LiFePO4 Journal of Power Sources Selected papers presented at the 11th International Meeting on Lithium Batteries 119 121 955 958 Bibcode 2003JPS 119 955S doi 10 1016 S0378 7753 03 00297 0 ISSN 0378 7753 S2CID 53992561 Ansean D Viera J C Gonzalez M Garcia V M Alvarez J C Antuna J L 2013 High power LiFePO4 cell evaluation Fast charge Depth of Discharge and Fast discharge dependency World Electric Vehicle Journal 6 3 653 662 doi 10 3390 wevj6030653 ISSN 2032 6653 support rollsbattery com AGM discharge characteristics Retrieved from https en wikipedia org w index php title Depth of discharge amp oldid 1206555336 Deep discharge, wikipedia, wiki, book, books, library,
