Lithium-ion Stationary Battery Capacity Sizing Formula For .
J Electr Eng Technol.2018; 13(6): 1ISSN(Print) 1975-0102ISSN(Online) 2093-7423Lithium-ion Stationary Battery Capacity Sizing Formula for theEstablishment of Industrial Design StandardChoong-koo Chang† and Mumuni Sulley*Abstract – The extension of DC battery backup time in the DC power supply system of nuclearpower plants (NPPs) remains a challenge. The lead-acid battery is the most popular at present. And itis generally the most popular energy storage device. However, extension of backup time requires toomuch space. The lithium-ion battery has high energy density and advanced gravimetric and volumetricproperties. The aim of this paper is development of the sizing formula of stationary lithium-ionbatteries. The ongoing research activities and related industrial standards for stationary lithium-ionbatteries are reviewed. Then, the lithium-ion battery sizing calculation formular is proposed for theestablishment of industrial design standard which is essential for the design of stationary batteries ofnuclear power plants. An example of calculating the lithium-ion battery capacity for a medium voltageUPS is presented.Keywords: lead-acid battery, Lithium-ion battery, Battery capacity sizing formular, Industrialstandard, Nuclear power plants.1. IntroductionRecently, as a result of competitive research anddevelopment efforts around the world, high capacity andhigh performance of energy storage systems (ESS) areaccelerating. The emergence of lithium-ion battery in 1991has got a wide range of application in energy storage devices.It has been widely used for portable electronic devices inthe early days. The application range is rapidly expandingfor electric vehicles and large ESS. Industrial standards hadbeen established for the sizing of conventional stationarybatteries such as lead-acid and nickel-cadmium batteries.However, the industrial standard for the sizing of lithiumion stationary batteries is still under development.IEC 62619-2017, ‘Safety requirements for secondarylithium cells and batteries, for use in industrial applications’and IEC 62620-2014, ‘Secondary cells and batteriescontaining alkaline or other non-acid electrolytes Secondary lithium cells and batteries for use in industrialapplications’ are international standard for industriallithium-ion batteries established recently. However, IEC62619 & 62620 does not cover the capacity sizingmethod of lithium-ion stationary battery. Korea ElectricAssociation published KEPIC EEG 1400, ‘Installationdesign and installation of lithium-ion batteries for stationapplications’ on December 31, 2017. KEPIC EEG 1400describes how to size lithium-ion stationary batteries but†Corresponding Author: Dept. of Nuclear Power Plant Engineering,KEPCO International Nuclar Graduate School, Korea.(ckchang @kings.ac.kr)*Dept. of Nuclear Power Plant Engineering, KEPCO InternationalNuclar Graduate School, Korea. (mumunigh@yahoo.com)Received: April 30, 2018; Accepted: October 1, 2018does not take into account all the characteristics of lithiumion batteries.Due to many advantages of lithium-ion over currentindustrial standard batteries such as lead-acid and nickelcadmium pose a need of great concern. The Japaneseearthquake and tsunami event on March 11, 2011 causedsimultaneous loss of offsite power (LOOP) and onsiteAC power (SBO). And, the extended loss of alternatingcurrent (ac) power (ELAP) condition led to loss of corecooling and a significant challenge to containment. Priorto recovery from an ELAP it is imperative that DC powerremain available for indication and for control before ACpower is restored. Nuclear energy institute (NEI), ‘Diverseand flexible coping strategies (FLEX) implementationguide’ (NEI 12-06, Aug. 2012) requires the 125 VDC class1E batteries to last for at least 24 hours. But the backuptime of existing lead-acid type safety related batteries is8 hours. Due to the low energy density, extending batterybackup time from 8 hours to 24 hours with currentdesign is unrealistic. Therefore, lithium-ion battery isrecommended as an alternative for lead-acid battery.The objective of this paper is to propose the lithiumion stationary battery capacity sizing formula for theestablishment of industrial design standard which isessential for the design and installation of stationarybatteries of nuclear power plants. Sample calculation forthe batteries of medium voltage UPS of a nuclear powerplants is also presented as an example. For this purpose,comparative analysis of stationary batteries is performedin Section 2. Based on the review results of Section 2,stationary lithium-ion battery capacity sizing formular isproposed in Section 3. Then, Section 4 provides calculationexample.Copyright The Korean Institute of Electrical EngineersThis is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.2561
Lithium-ion Stationary Battery Capacity Sizing Formula for the Establishment of Industrial Design Standard2. Stationary Battery Comparative AnalysisLithium-ion batteries have a high energy density ofapproximately five times of lead-acid batteries, a dischargeloss of only 1/4 of that of nickel-metal hydride batteries,have no memory effect, and have a large number of chargeand discharge cycles as shown in Table 1 [1]. On the otherhand, lithium-ion batteries suffer from severe performancedegradation at high temperatures, and when the batteriesare completely discharged, the batteries lose their functionsand on cost basis they are expensive compared to otherbatteries. Also, if handled inadvertently, there is a risk ofexplosion.2.1 Single cell voltageThe lithium-ion battery can be manufactured by usinglithium cobalt oxide (LiCoO2 or LCO), lithium manganeseoxide (LiMn2O4 or LMO), and lithium nickel manganesecobalt oxide (LiNiMnCoO2 or NMC, NCM, CMN, CNM,MNC, MCN), lithium iron phosphate (LiFePO4) andlithium titanate (Li4Ti5O12) as shown in Table 2 [2].2.2 Discharge characteristicsThe discharge characteristics of lead-acid batteries,which are mainly used for industrial purposes, are explainedby the following Peukert’s law.t Qpt : Discharge time to reach discharge terminatingvoltage [s]k : Constant, approximately 1.3.The discharge capacity of the lead-acid battery variesdepending on the discharge current due to the Peukertformula k constant. The larger the discharge current, thegreater the difference in discharge capacity. In other words,the discharge capacity of a lead-acid battery exponentiallydecreases at high currents as shown in Fig. 1[3]. On theother hand, the lithium-ion battery has a k-constant close tounity. This means that the discharge capacity of the batterydoes not vary greatly depending on the magnitude of thedischarge current and exhibits good discharge characteristics at high currents as shown in Fig. 2 [4].2.3 Operating temperature characteristicsLithium-ion batteries are capable of operating over arelatively wide temperature range. And, it is more affectedby temperature during charging than discharging.Charging performance deteriorates at extremely low orhigh temperatures. Lead-acid batteries can be charged atbelow 0 C. However, the recommended charging current is0.3C. The higher the temperature, the greater the dischargecapacity of lead-acid batteries as listed in Table 3[5]. All(1)Ikwhere;Qp : Discharge capacity when discharging at 1A [Ah]I : Discharge current [A]Table 1. Types and performance of batteriesOperating Energy Life expectancy Batteryvoltagedensity[year]efficiency[V][Wh /kg](Cycle)[%]Lead accumulator2.020-357-10 (1500)65-80Nickel hydrogen1.220-70(500 1500) 84accumulatorLithium-ion2.4 -3.870-160 10( 3600) 95accumulatorAccumulatorkindsFig. 1. Typical discharge curves of lead-acid batteriesTable 2. Lithium-ion battery voltageLiCoO2Lowest3.0Voltage 2.44.22.85Battery typeUsage fieldCell phones, TabletsMedical equipment,tramElectric vehicles,industrialHigh current loadbatteryIndustrial, tramUPS, tram2562 J Electr Eng Technol.2018; 13(6): 2561-2567Fig. 2. Discharge characteristics of Lithium-ion battery(Power Cell)
Choong-koo Chang and Mumuni SulleyTable 3. Permissible temperature for battery operationAccumulatorformChargingTemp. [o C]DischargeTemp.[o C]Lead-acid-20 50-20 50NiCd, NiMH0 45-20 65Li-ion0 45-20 60Charging Notice 0.3C at belowfreezing point75% charge at 45 CDo not charge atbelow 0 Cand represents the maximum amount of charge that can bestored in the battery. Most batteries have a distinct chargevoltage. Below that voltage battery is not charged, abovethat voltage battery is fully charged, even though it mighttake a long time if the voltage is barely above the chemistryvoltage. However, lithium-ion (lithium-ion, lithium polymer,lithium iron phosphate, etc.) batteries are not the same withother type of batteries. The amount of charging depends onthe voltage as shown in Fig. 3[7]. Therefore, battery sizeshall be decided not by the nominal capacity but by thecapacity at the time of starting discharge and it depends onfloat charging voltage.3. Calculation of Lithium-ion Battery Capacity3.1 Related industrial standardsFig. 3. Charging voltage and discharge capacity of lithiumion batterybatteries achieve optimum service life if used at 20 C orslightly below. At 40 C, the loss jumps to a whopping 40percent, and if charged and discharged at 45 C, the cyclelife is only half of what can be expected if used at 20 C.The performance of all batteries drops drastically at lowtemperatures. At 0 C the temperature loss of the lithiumion battery is about 10 20 percent of its rated capacity at25 C [5].2.4 State of charge and charging voltageThe state of charge(SOC) is one of the most importantparameter for the stationary lithium-ion battery sizing. Ingeneral, stationary batteries are operated with floatingcharging, and discharge to the loads when charging sourceis interrupted. There is approximately a linear relationshipbetween the SOC of the lead-acid battery and its opencircuit voltage (OCV). Unlike the lead-acid battery, the Liion battery does not have a linear relationship between theOCV and SOC [6]. The SOC of a battery is defined as theratio of its current capacity ( ( )) to the nominal capacity( ). The nominal capacity is given by the manufacturerThe DC battery system of nuclear power plants shouldcomply with the requirements of IEEE Std.946 for thenumbers of battery [8], IEEE std.384 for the separationrequirement [9], and regulatory guide RG1.75[10 ] for otherrequirements. The capacity of lead-acid battery is decidedin accordance with IEEE std 485[11]. However, internationalindustrial standards for the stationary lithium-ion batterycapacity sizing is not yet established. Recently Koreaelectric industry code(KEPIC) EEG 1400 was issued andit is the only standard for the sizing and installation ofstationary lithium-ion batteries. But it does not take accountof state of charge (SOC) characteristics [12]. And notsufficient information and guidance are provided for theapplication of the code. Therefore, this paper proposes amethod that can be used to determine the size of stationarylithium-ion battery taking into account the state of chargecharacteristics.3.2 Battery capacity calculation formulaThe following is the capacity and dimension sizingmethod for lithium-ion battery proposed by this paper.Fs Fd S f(2)whereFs is the capacity required by UPS [Wh];Fd is the battery capacity uncorrected for temperature,aging, and design margin etc.;Sf is the capacity correction factorand,Sf (1 df ) (1 tf ) (1 cf ) (1 cf ) (1 if )(3)wheredf is the design margin;tf is the temperature correction factor;cf is the state of charge (SOC) correction;http://www.jeet.or.kr 2563
Lithium-ion Stationary Battery Capacity Sizing Formula for the Establishment of Industrial Design Standardafifis the aging compensation;is the inverter loss (for UPS battery only).The capacity correction factors are estimated as below.The design margin df recommended by IEEE 485 is 10 to15%. A lower capacity is expected for the low temperaturethermal performance test (10 C), and a higher capacity isexpected for the high temperature (45 C) due to thetemperature-related kinetic and thermodynamic effects. Forthe exact tempertature correction factor, tf should consultwith battery manufacturer and typical data in Fig. 4 may beused for preliminary input data [13]. Lithium-ion battery isdegraded at above 35 C especially at beyond 50 C [14].The SOC of the lithium-ion battery depends on thecharging voltage. The stationary battery is operated withfloating charging mode during normal operation. Dischargecapacity of the lithium-ion battery is decided by thecharging voltage just before starting discharge. Fig. 3shows the example of discharge capacity curves whichdepends on charging voltage. The battery capacity will bemonitored by conducting the performance test, normally itis done within the first two years of service for comparisonpurpose to check if the results are similar in duration tothe battery duty cycle [15]. If the battery is replacedFig. 4. Relative capacity and temperature of lithium-ionbatterywhen the discharge capacity of the battery reaches 80%of the manufacture’s rating, then the aging compensationfactor is 25%.4. Sample Calculation of Battery Capacity4.1 Stationary batteries for nuclear power plantsRedundant DC 125V systems are installed for bothsafety and non-safety loads of the nuclar power plant. The250 V DC systems are installed for non-safety large loadssuch as DC emergency motors for turbine and generator.However, calculation has been done for the mediumvoltage UPS DC batteries sizing, as an example instead ofDC 125V or 250V system battery. That is because thecapacity of proposed MV UPS battery is biggest in thenuclear power plants. Fig. 5 shows the 4.16 kV mediumvoltage UPS for the safety buses of an APR1400 NPP. Itwas proposed for the enhancement of reliability and safetyof nuclear power plants [16]. The MV UPS is classified asnon-safety related equipment and connected to safetyrelated bus by isolation circuit breaker.The operation duration of the 4.16kV UPS is limited to15 minutes when the offsite and onsite power are lost at thesame time. If the emergency diesel generator (EDG) failsto start, the UPS supplies power to the safety bus until thealternative AC (AAC) generator starts within 10 minutesafter loss of offsite and onsite power. In addition to 10minutes, interruption time of 5 minutes of safety margin isincluded. If the ACC fails to start, station blackout (SBO)countermeasures will be taken only by the DC powersupply.According to Table 4 required uncorrected batterycapacity of Bus-01A(Fd-01A) and Bus-02A(Fd-02A) are asbelow:Fd-01A 6.08 MW 15/60 hr 1.52 MWhFd-02A 2.49 MW 15/60 hr 0.62MWhand, capacity correction factor Sf is determined as follows:Sf (1 0.1:) (1 0.05) (1 0.10) (1 0.25) (1 0.005) 1.596where each correction factor was applied as below:df ;10% , tf ; 5%, cf ; 10%, af ; 25% and i ; 0.5%The design margin was decided as 10% because furtherextention of safety related loads is not highly expected.Table 4. Safety bus load capacity [MW]Fig. 5. Class 1E 4.16 kV Buses of a APR1400 (Division Ionly)2564 J Electr Eng Technol.2018; 13(6): 2561-2567DivisionDuring normal operationLoss of coolant accident (LOCA)4.16 kV- 01A4.626.084.16 kV – 02A1.192.49
Choong-koo Chang and Mumuni SulleyAssuming that the HVAC system do not operate during theAC power loss, the ambient temperature of the batteriesmay go down below 25 C, so the temperature correctionfactor of 5% was applied (See Fig. 4). The SOC correctionfactor of 10% was applied to compensate the capacityreduction due to the floating charging voltage duringnormal operation being lower than cell maximum voltage.Rated voltage of the DC system is 777V 10%. In that case,battery cell voltage is 3.7V 10%. That means floatingvoltage is maximum 4.07 V and it is 97% of maximum cellvoltage (4.2 V). As a result, battery discharge capacityreduction is minimum 10% [17]. The acceptence criteria ofthe battery aging test is 80% of rated capacity. Thereforeaging compensation margin was decided as 25%. In anaccerlerated aging test(60 C, 8.3 months), lithium-ionbattery capacity was reduced to 87.03% [18]. In addition,5% inverter loss was added based on manufacturer data.Required battery capacity of the bus Fs-01A and Fs-02A is asbelow:Fs-01A 1.52 1.596 2.43 MWhFs-02A 0.62 1.596 0.99 MWh4.2 Battery cell and system selectionThe lithium-ion battery systems suitable for the abovebattery capacity are selected by referring to the ESSspecification of a domestic company [19].Battery system for Bus-01A :a) Battery Module Capacity: 11,655 Wh Cell Type: 150 Ah (75 Ah 2) Nominal Voltage : 77.7 V (3.7 V 21) Connection Type : 21 Series 2 Parallelsb) Battery Cubicle Number of Modules : 10 Modules/Cubicle Connection Type : 10 Parallels Cubicle Capacity : 1,500 Ah (150 10 Module) Dimension(W D H) : 1,150 740 2116 mmThe following factor was assumedc) Battery System Specification Number of Cubicles: 20 Cubicles System connection Type: 2P 10S Cubcles Capacity: 3,000 Ah (1,500 Ah 2 Cubicles) Energy: 2.33 MWh (3,000 Ah 777V) Nominal Voltage : 777 V Foot Print: 17 m2 (0.85 m2 20 Cubicles)d) Practical capacity correction factor : 2.33 MWh/1.52MWh 1.53.Battery system for Bus-02A :a) Battery Module Capacity: 11,655 Wh Cell Type: 150 Ah (75 Ah 2) Nominal Voltage : 77.7 V (3.7 V 21) Connection Type : 21 Series 2 Parallelsb) Battery Cubicle Number of Modules : 10 Modules/Cubicle Connection Type : 10 Parallels Cubicle Capacity : 1,500 Ah (150 10) Dimension(WxDxH) : 1,150 740 2116 mmThe following factor was assumedc) Battery System Specification Number of Cubicles: 10 Cubicles System connection Type: 10S Cubcles Capacity: 1,500 Ah Energy: 1.165 MWh (1,500 Ah 777V) Nominal Voltage : 777 V Foot Print: 8.5 m2 (0.85 m2 10 Cubicles)d) Practical capacity correction factor: 1.165MWh/0.62MWh 1.88.4.3 Equivalent lead-acid battery capacity and sizeSelected a battery [20] qualified for nuclear power plantapplication and calculated estimated capacity and areasrequired for battery installation. Lead-acid battery capacirysizing was performed in accordance of the equation (4) ofIEEE 485.S NF max å P 1 [ Ap - A( p-1) ]ktP s(4)S 1whereFSNPAptktis uncorrected cell size;is the section f the duty cyclce being analyzed;is the number of periods in the duty cycle;is the period being analyzed;are the amperes required for period P;is the time in minutes from the beginning of periodP through the end of section S;is the ratio of rated ampere-hour capacity of cell, tothe amperes that can be supplied by the cell for tminutes at 25 C and to a given minimum cellvoltage.Table 5. Equivalent lead-acid batteryDescriptionDuty cycleDischarge timeBattery cell capacity[10 h rate]ktUncorrected sizeCorrection factorRequired sizeNominal cell voltageCell end coltageBattery system voltageMinimum voltageNumber of cellsFoot printBus-01A8,106.7 A15 MinBus- 02A3,320 A15 Min3600 Ah3600 Ah1.5212,322.1 Ah1.4517,867.1 Ah2.0 V1.81 V750 V678 V1,875(375 S 5 P)179.39 m21.525,046.4 Ah1.457,317.3 Ah2.0 V1.81V750 V678 V750(375 S 2 P)71.76 m2http://www.jeet.or.kr 2565
Lithium-ion Stationary Battery Capacity Sizing Formula for the Establishment of Industrial Design StandardIn this calculation analysis period(P) is one periodbecause the load is UPS. The following is the ratings andcalculated data of lead-acid battery system providing thesame capacity with the above lithium-ion battery;[4][5]5. Results and ConclusionsT
However, the industrial standard for the sizing of lithium-ion stationary batteries is still under development. IEC 62619-2017, ‘Safety requirements for secondary lithium cells and batteries, for use in industrial applications’ and IEC 62620-2014, ‘Secondary cells and batteries
14-100508-000 Assy. Lithium Battery, 30 Ahr 14-100508-900 Assy. Lithium Battery, preown 30 Ahr 14-100957-002 Assy. Lithium Battery, w/ jumper 48 Ahr 14-100957-004 Assy. Lithium Battery, w/ jumper 30 Ahr 14-100957-904 Assy. Lithium Battery, preown 30 Ahr 14-860202-002 Pkg. Envoy, Lithium, with ACDC 115V 14-860202-004 Pkg. Envoy w/ Lithium .
3.2 Battery capacity calculation formula The following is the capacity and dimension sizing method for lithium-ion battery proposed by this paper. Fs Fd Sf (2) where Fs is the capacity required by UPS [Wh]; Fd is the battery capacity uncorrected for temperature, aging, and design margin etc.; Sf is the capacity correction factor and,
1. Are all lithium-ion batteries created equal? — NO 2. Are all chemistries the same? — NO 3. Are all batteries using the same lithium-ion chemistry the same? — NO 4. Do all lithium-ion batteries have similar cycle life, like Flooded Lead Acid (FLA)? — NO 5. Can I use any lithium-ion battery in my equipment? — NO 6.
Lithium battery types covered by this Guide include lithium-ion, lithium-alloy, lithium metal, and lithium polymer types. For requirements related to conventional battery types, please refer to 4-8-3/5.9
Extinguishing Agents for Lithium-ion Batteries 05 -23 13 2 Background Growth in Lithium Battery Use -The number of lithium-ion batteries made in the world grew from about 800 million in 2002 to about 4.4 billion in 2012. Fire Risk -Many lithium ion cells have been known to overheat and create a potentially dangerous situation.
Lithium Nickel Manganese Cobalt Oxide or “Li-ion-NMC” is the more commonly available lithium-ion battery type and is the least expensive lithium-ion battery on the market. It is important to recognize that Li-Ion-NMC batteries can overheat and catch fire in rare cases of overcharging or improper use. This is known as “thermal runaway”.
The DW01-P battery protection IC is designed to protect lithium-ion/polymer battery from damage or degrading the lifetime due to overcharge, overdischarge, and/or overcurrent for one-cell lithium-ion/polymer battery powered systems,
polyatomic ions: a. amm onium ion b. sulfate ion c. sulfite ion d. carbonate ion e. nitrate ion f. permanganate ion g. hypochlorite ion h. phosphate ion i. cyanide ion j. hydroxide ion 9.2 Naming and Writing Formulas for Ionic Compounds A. _ Ionic Compounds 1. What are Binary Ionic Compounds? 2.
