PDF Publication Title:
Text from PDF Page: 020
UnderstandininggththeeVVaannaaddiuimumRRedeodxoFxloFwlowBaBttaetrtiesries 31591 Therefore, it should exist an optimal flowrate Qopt somewhere between Qmin and Qmax that increases Pstack while maintaining Pmech at a small value. 8.1 Optimal flowrate during the discharge In this section, the battery is controlled by the reference current Istack,re f ; therefore there is only one control variable: the flowrate Q. Indeed, the stack power Pstack depends on Istack, Q and the state of charge SoC whereas the mechanical power depends on Q and the electrolyte properties: the density ρ and the viscosity μ that are maintained constant in this work. During the discharge, the optimal operating point is found when the flowrate Qopt maximizes the power delivered by the stack Pstack while minimizing the mechanical power Pmech. When these conditions are met together, the power delivered by the battery PVRB is optimized: 2500 2000 1500 1000 500 SoC = 0.025 SoC = 0.03 SoC = 0.035 SoC = 0.04 SoC = 0.045 SoC = 0.05 SoC = 0.1 SoC = 0.2 SoC = 0.3 SoC = 0.4 SoC = 0.5 SoC = 0.6 SoC = 0.7 SoC = 0.8 SoC = 0.9 SoC = 0.95 SoC = 0.975 Maximal Power max( PVRB ) = max( f(Ustack,IVRB) Pstack − Pmech ) (40) f(Istack,Q,SoC) f(Q,μ,ρ) In Fig. 17, PVRB is represented during the discharge as a function of Q at different states of charge for a current of 100 A. Clearly, an optimal flowrate Qopt exists between Qmin and Qmax that maximizes PVRB. The shape of the curves can be generalized to other discharge currents Istack > 0; although in some cases where Istack is low, PVRB might become negative at inappropriately high flowrate Q. P VRB = P Stack − P mech , I = 100 A P VRB [W] 0 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 Q [l/s] Fig. 17. Optimal flowrate Qopt as a function of the flowrate Q and the state of charge SoC. Note that when SoC is low, Qopt is equal to the minimal flowrate Q, and the discharge current is equal to 100 A. 8.2 Optimal flowrate during the charge At constant current Istack,re f , the quantity of electrons e− stored in the electrolyte does not depend on the stack power Pstack but solely on the stack current Istack; therefore, there is no reason to have a high Pstack. Hence, the optimal flowrate Qopt during the charge is foundPDF Image | Understanding the Vanadium Redox Flow Batteries
PDF Search Title:
Understanding the Vanadium Redox Flow BatteriesOriginal File Name Searched:
12523.pdfDIY PDF Search: Google It | Yahoo | Bing
Salgenx Redox Flow Battery Technology: Salt water flow battery technology with low cost and great energy density that can be used for power storage and thermal storage. Let us de-risk your production using our license. Our aqueous flow battery is less cost than Tesla Megapack and available faster. Redox flow battery. No membrane needed like with Vanadium, or Bromine. Salgenx flow battery
CONTACT TEL: 608-238-6001 Email: greg@salgenx.com (Standard Web Page)