NL2037312B1

NL2037312B1 - electrolyte storage tank for a redox flow battery system

Info

Publication number: NL2037312B1
Application number: NL2037312A
Authority: NL
Inventors: Van Dijk Willem-Jan; Berend Kout Wiebe; Elemans Marten; Siebren Steen Jelte
Original assignee: Elestor B V
Priority date: 2024-03-22
Filing date: 2024-03-22
Publication date: 2025-10-02
Also published as: WO2025198474A1

Abstract

The present invention relates to an electrolyte storage tank for a redox flow battery system. The electrolyte storage tank for a redox flow battery system according to the present invention comprises a closed loop of liquid electrolyte and gas between the redox flow battery system and the electrolyte storage tank. An object of the present invention is to develop a redox flow battery system wherein the amount of parasitic power for the flow battery system is drastically reduced and wherein the requirements for additional equipment, such as the use of demi water for gas humidification, are reduced as well.

Description

Title: electrolyte storage tank for a redox flow battery system

Description:

The present invention relates to an electrolyte storage tank for a redox flow battery system.

Redox flow battery systems are well known in the art. For example, European patent application EP 3 087 634 in the name of the present application relates to a hydrogen-redox flow battery assembly comprising: one or more battery cells, each battery cell comprising: a hydrogen chamber configured to house a flow path of hydrogen gas between a hydrogen inlet and a hydrogen outlet; an electrolyte chamber configured to house a flow path of liquid electrolyte between an electrolyte inlet and an electrolyte outlet; a membrane electrode assembly, the membrane electrode assembly configured to only allow a diffusion of protons through the membrane electrode assembly between the hydrogen gas in the hydrogen chamber and the liquid electrolyte in the electrolyte chamber; a hydrogen reservoir connected to the hydrogen chamber of the one or more battery cells and configured to retain the hydrogen gas; and an electrolyte reservoir connected to the electrolyte chamber of one or more battery cells and configured to retain the liquid electrolyte.

International application WO 2023/121454 in the name of the present applicant relates to a flow battery system, comprising a first tank including a hydrogen reactant, a second tank including a bromine electrolyte, at least one cell including a hydrogen reactant side operably connected to the first tank through an H; feed and return system and a bromine electrolyte side operably connected to the second tank through a bromine electrolyte feed and return system.

International application WO 2018/201070 relates to liquid- liquid flow batteries, especially to a multi-chambered electrolyte storage tank for a redox flow battery system, including first and second electrolyte chambers, and a bulkhead, wherein the first and second electrolyte chambers are fluidly coupled to first and second sides of a redox flow battery cell, respectively, the first and second electrolyte chambers include first and second liquid electrolyte volumes, respectively, and the first and second liquid electrolyte volumes are separated by the bulkhead positioned therebetween. Such a multi-chambered electrolyte storage tank further comprises first, and second return manifolds submersed and fluidly coupled to the submersed positions in the first and second volumes, wherein the first and second return manifolds include liquid electrolyte and entrained gases therein returned from the redox flow battery cell.

International application WO2021052782A1 relates to liquid- liquid flow batteries, especially to a battery storage for a redox flow battery with at least one cavity, an electrolyte being stored in the cavity, the electrolyte being in fluid communication with at least one redox flow cell, and the cavity being a cavern, wherein in the area of the cavern roof a gas is stored which is in fluid connection with an above- ground gas infrastructure and the electrolyte is stored on the cavern floor, wherein the gas volume and/or the gas pressure can be variably adjusted via the gas infrastructure, wherein the volume of the electrolyte is constant and circulates across the redox flow battery. Examples of a useful gas are natural gas, hydrogen, or the like, i.e. in particular a gas that can be distributed via a spatially distributed gas distribution network and is stored in the cavern in the area of the cavern roof.

Other examples of flow battery systems are, inter alia, disclosed in International application WO 2013/086100, US 2012/299384, US 2015/188178, and US 2016/0322653.

US 2018/316036 relates to a redox flow battery system comprising a redox flow battery cell fluidly coupled to positive and negative electrolyte chambers, dry electrolytes located in the positive and negative electrolyte chambers with less than a threshold amount of solvents, a field hydration system detachably coupled to a water source arranged externally to the redox flow battery, and a controller, including executable instructions stored thereon to activate a water supply pump of the field hydration system configured to flow water from the water source to the positive and negative electrolyte chambers. The gas head space located above the fill height of positive electrolyte chamber may be utilized to store hydrogen gas generated through operation of the redox flow battery (e.g., due to proton reduction and corrosion side reactions) and conveyed to the multi-chambered storage tank with returning electrolyte from the redox flow battery cell. The hydrogen gas may be separated spontaneously at the gas-liquid interface within the multi-chambered storage tank 110, thereby precluding having additional gas-liquid separators as part of the redox flow battery system. Once separated from the electrolyte, the hydrogen gas may fill the gas head spaces located above the fill height of both the negative and positive electrolyte chamber. The stored hydrogen gas can aids in purging other gases from the multi- chamber storage tank, thereby acting as an inert gas blanket for reducing oxidation of electrolyte species, which can help to reduce redox flow battery capacity losses.

JP2010 170782 relates to a redox flow battery comprising a battery tank, an ion exchange membrane provided inside the battery tank to divide the internal space into a positive electrode chamber and a negative electrode chamber, a positive electrode plate and a negative electrode plate provided in the positive electrode chamber and the negative electrode chamber, respectively, a first tank for accommodating a first electrolytic solution containing a positive electrode active material, an ionic liquid, and water, a second tank for accommodating a second electrolytic solution containing a negative electrode active material, an ionic liquid, and water, and a first circulation path section for circulating the first electrolytic solution between the first tank and the positive electrode chamber.

US 2012/299384 relates to energy storage and generation systems, e.g. a combination of flow battery and hydrogen fuel cell, that exhibit operational stability in harsh environments, e.g., both charging and discharging reactions in a regenerative fuel cell in the presence of a halogen ion or a mixture of halogen ions. Such energy storage and generation systems are capable of conducting both hydrogen evolution reactions (HERs) and hydrogen oxidation reactions (HORS) in the same system.

WO 2015/100216 relates to a flow battery system, comprising a first tank including a hydrogen reactant, a second tank including a bromine electrolyte, at least one cell including a hydrogen reactant side operably connected to the first tank through an H2 feed and return system and a bromine electrolyte side operably connected to the second tank, and a crossover return system including a vessel operably connected to the H2 feed and return system and configured to receive an effluent containing a first portion of the hydrogen reactant and a second portion of the bromine electrolyte, the vessel configured to separate the first portion from the second portion, a first return line operably connecting the vessel to the first tank to return first portion of the hydrogen reactant to the first tank, and a second return line operably connecting the vessel to the second tank to return the bromine electrolyte to the second tank.

EP 2 963 723 in the name of the present applicant relates to a hydrogen-redox flow battery assembly comprising one or more battery cells, each battery cell comprising a hydrogen chamber configured to house a flow path of hydrogen gas between a hydrogen inlet and a hydrogen outlet, an electrolyte chamber, a membrane electrode assembly comprising a hydrogen electrode and an electrolyte electrode, and a membrane positioned between the hydrogen chamber and the electrolyte chamber, wherein the hydrogen-redox flow battery assembly is further configured to allow an uncontrolled pressure difference between the pressure in the hydrogen chamber of the battery cell and the pressure in the electrolyte chamber of the battery cell.

In operation of a flow battery heat is produced and in practice external cooling systems, for example dry coolers or chillers, are installed to remove the heat generated in the battery system. Such active cooling of the liquid electrolyte requires thus additional process equipment and energy.

In addition, for performance and lifetime of flow battery cells it is advantageous to apply a humidified gas flow through the battery system. In practice humidifiers, such as bubble systems, are used for humidifying the gas flow. Such a construction would introduce additional components, e.g. demi water, into the battery system. In addition, such humidifiers also consume electricity.

An object of the present invention is to develop a redox flow battery system wherein the above mentioned disadvantages are minimized.

More in detail, an object of the present invention is to develop a redox flow battery system wherein the amount of parasitic power for the flow battery system is drastically reduced and wherein the requirements for additional equipment, such as the use of demi water for gas humidification, are reduced as well.

The present invention thus relates to an electrolyte storage tank for a redox flow battery system comprising a closed loop of liquid electrolyte and gas between the redox flow battery system and the electrolyte storage tank, wherein liquid electrolyte used in the redox flow battery system is stored in the electrolyte storage tank and gas used within the redox flow battery system is stored in the same electrolyte storage tank, wherein evaporative cooling of the liquid electrolyte takes place for humidifying the gas, wherein both the liquid electrolyte thus cooled and the gas thus humidified are returned to the redox flow battery system.

On basis of such a method the present object is achieved. The present inventors found that in the combined storage of liquid electrolyte and gas, the evaporation cooling of the liquid electrolyte will be used to partially cool the liquid electrolyte. Such an action will reduce the dependency of the battery system on active cooling systems. In addition, as the liquid electrolyte evaporates the water damp will also humidify the gas present in the electrolyte storage tank. According to the present invention the processes of cooling and evaporation are passive and combined within the battery system. 5 In an example the electrolyte storage tank for a redox flow battery system is in a pressurized condition.

In another example the electrolyte storage tank for a redox flow battery system is in an unpressurized condition.

In an example the gas is chosen from the group of Hz, CO,, CO, O,, NH,, Br, and Cl. A preferred gas is Ho.

In an example the liquid electrolyte comprises sulfuric acid.

In an example the liquid electrolyte comprises a combination of a metal active species and a mineral acid, wherein the metal active species is chosen from the group of Fe, Ti, V, Cr, Mn, Co, Ni, Cu, Zn and Cs, or a combination thereof and the mineral acid is chosen from the group of H2SO4, H3PO4, H3BO3, H4SiO,, HCIO,4, HF, HCI, HBr,

Hi and HNO3, or a combination thereof.

In an example the liquid electrolyte further comprises one or more metal additives chosen from the group of Li, Na, K, Rb, Mg and Ca.

Preferred examples of a liquid electrolyte comprise combinations of metal active species chosen from the group of Fe, Mn, V, Ti, and Cr with mineral acids chosen from the group of HSO, and HCI, as these have advantages in combination with the redox reaction of hydrogen. Examples of liquid electrolyte are Fe/ H,S0,, Mn/

H,S0,, V/ H2S0,, Ti/ H;SO,, Cr/ H2S0,, Fe/HCI, Mn/ HCI, V/ HCI, Ti/ HCI and Cr/

HCI.

In another example the liquid electrolyte comprises a combination of an organic active species and a mineral acid.

The organic active species ís chosen from the group of quinone, anthraquinone, phenazine, methylene blue, (2,2,6,6-tetramethylpiperidin-1-yhoxyl, (2,2,6,6- tetramethylpiperidin-1-yhoxidanyl (TEMPO) and organic compounds with formula (CsHa4NR)2"* (viologen), or a combination thereof.

The mineral acid is chosen from the group of H2SO4, H3POa, H3BO3, HaSiOs,

HCIO,, HF, HCI, HBr, HI and HNO3, or a combination thereof.

Preferred examples of such liquid electrolytes are combinations of an organic active species and a mineral acid anthraquinone/ H2SO,, methylene blue/ H2S0,4, quinone/ H2SO3, anthraquinone/ HCI, methylene blue/ HCI and quinone/ HCI, as these have advantages in combination with the redox reaction of hydrogen. In an example the liquid electrolyte is chosen from the group of anthraquinone, methylene blue and quinone with mineral acids chosen from the group of H,SO. and HCI.

In an example the liquid electrolyte further comprises one or more organic additives chosen from the group of citric acid, oxalic acid, phosphoric acid, formic acid, ascorbic acid, acetic acid, propionic acid, benzoic acid, EDTA, DTPA, maleic acid, tartaric acid, succinic acid, phthalic acid, malonic acid, lactic acid, butyric acid, valeric acid, picolinic acid, humic acid, fulvic acid, sulfosalicylic acid, triflic acid, alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, valine, methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, acetone, phenol, pyridine, pyrrolidine, piperidine, nitromethane, dimethylsulfoxide, tetrahydrofuran, ethylene carbonate, propylene carbonate, dimethyl carbonate, choline, lignin, acetonitrile, ethylene glycol, formamide, dimethyformamide, glycerine, urea, ammonia, orthophenanthroline, hexamethylphosphoramide or a combination thereof. The total amount of such additives in the liquid electrolyte is in a range of at least 1 wt.%, preferably 20 wt.% and at most 50 wt.%, preferably at most 25 wt.%, based on the total weight of the liquid electrolyte.

Preferred examples of organic additives are citric acid, phosphoric acid, oxalic acid, acetic acid, humic acid, ethylene carbonate, ethanol, urea, ammonia and formamide, or a combination thereof, as these have advantages due to the availability of materials as well as the advantages in power and energy density.

In an example the gas used within the redox flow battery system is bubbled through the liquid electrolyte present in the electrolyte storage tank. After bubbling the gas is stored in the electrolyte storage tank. Such a construction of the flow of gas through the liquid electrolyte has a beneficial effect on the humidification of the gas.

In an example the surface of the liquid electrolyte present in the electrolyte storage tank is partially covered to regulate the amount of evaporation and thereby evaporation cooling of the liquid electrolyte.

Figure 1 shows a flow battery system according to the present invention.

The present invention will be illustrated by way of an example.

In figure 1 a flow battery system 1 is schematically shown. Electrolyte storage tank 4 for a redox flow battery system 1 comprises a closed loop of liquid electrolyte 8 and gas 5, e.g. gaseous hydrogen between redox flow battery system 1 and electrolyte storage tank 4. Liquid electrolyte 8 used in redox flow battery system 1 is transported via line 9 to electrolyte storage tank 4 and stored therein. Gas 5 used within redox flow battery system 1 is transported via line 10 in the same electrolyte storage tank 4. Evaporative cooling (shown by reference number 6) of liquid electrolyte 8 takes place and gas 5 is thereby humidified. Liquid electrolyte 8 thus cooled is returned via line 3 to redox flow battery system 1. Gas 5 thus humidified is returned via line 2 to redox flow battery system 1. On basis of that construction a closed loop of liquid electrolyte 8 and gas 5 between redox flow battery system 1 and electrolyte storage tank 4 is realized. The humidification of the gas from redox flow battery system 1 can be improved by bubbling of the gas through the liquid electrolyte before returning it to the redox flow battery system.

Claims

CONCLUSIONS

1. An electrolyte storage tank for a redox flow battery system, comprising a closed circuit of liquid electrolyte and gas between the redox flow battery system and the electrolyte storage tank, wherein the liquid electrolyte used in the redox flow battery system is stored in the electrolyte storage tank and the gas used in the redox flow battery system is stored in the same electrolyte storage tank, wherein evaporative cooling of the liquid electrolyte takes place to humidify the gas, wherein both the liquid electrolyte thus cooled and the gas thus humidified are returned to the redox flow battery system,

2. The electrolyte storage tank for a redox flow battery system according to claim 1, wherein the electrolyte storage tank is pressurized.

3. The electrolyte storage tank for a redox flow battery system according to claim 1, wherein the electrolyte storage tank is not pressurized.

An electrolyte storage tank for a redox flow battery system according to any one of claims 1 to 3, wherein the liquid electrolyte comprises a combination of a metal active species and a mineral acid, wherein the metal active species is selected from the group consisting of Fe, Ti, V, Cr, Mn, Co, Ni, Cu, Zn and Cs, or a combination thereof, and the mineral acid is selected from the group consisting of H2S0O,4, H3POa, H3BO3, H4SiO,, HCIO,, HF, HCl, HBr, Hi and HNO, or a combination thereof.

5. The electrolyte storage tank for a redox flow battery system according to claim 4, wherein the liquid electrolyte comprises combinations of metal active species selected from the group of Fe, Mn, V, Ti, and Cr with mineral acid selected from the group of H, S0, and HCl

6. An electrolyte storage tank for a redox flow battery system comprising any one of claims 1 to 3, wherein the liquid electrolyte comprises a combination of an organic active species and a mineral acid, wherein the organic active species is selected from the group consisting of quinone, anthraquinone, phenazine, (2,2,6,6-tetramethylpiperidin-1-yl)oxy, (2,2,6,6-tetramethylpiperidin-1-yl)oxydanyl (TEMPO) and organic compounds of the formula (CsH4NR)}2"* (viologen), or a combination thereof, and the mineral acid is selected from the group consisting of H2SOa4, HsPO4, H3BO4, H4SiO4, HCl04, HF, HCl, HBr, Hi4 and HNO3, or a combination thereof.

7. An electrolyte storage tank for a redox flow battery system according to claim 6, wherein the liquid electrolyte is selected from the group of anthraquinone, methylene blue and quinone with mineral acids selected from the group of H,S0O, and

HCI.

8. An electrolyte storage tank for a redox flow battery system according to any one of claims 1 to 7, wherein the liquid electrolyte further comprises one or more metal additives selected from the group of Li, Na, K, Rb, Mg and Ca.

9. An electrolyte storage tank for a redox flow battery system according to any one of claims 1 to 3 and 6 to 7, wherein the liquid electrolyte further comprises one or more organic additives selected from the group consisting of citric acid, oxalic acid, phosphoric acid, formic acid, ascorbic acid, acetic acid, propionic acid, benzoic acid, EDTA, DTPA, maleic acid, tartaric acid, succinic acid, phthalic acid, malonic acid, lactic acid, butyric acid, valeric acid, picolinic acid, humic acid, fulvic acid, sulfosalicylic acid, triflic acid, alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, valine, methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, acetone, phenol, pyridine, pyrrolidine, piperidine, nitromethane, dimethyl sulfoxide, tetrahydrofuran, ethylene carbonate, propylene carbonate, dimethyl carbonate, choline, lignin, acetonitrile, ethylene glycol, formamide, dimethylformamide, glycerin, urea, ammonia, orthophenanthroline, hexamethylphosphoramide, or a combination thereof.

10. An electrolyte storage tank for a redox flow battery system according to claim 9, wherein the total amount of one or more organic additives is in a range of at least 1 wt%, preferably 20 wt% and at most 50 wt%, preferably at most 25 wt%, based on the total weight of the liquid electrolyte.

11. An electrolyte storage tank for a redox flow battery system according to any one of claims 1 to 10, wherein the gas is selected from the group consisting of Ha, CO, CO, O, NH, Br, and Cl.

12. An electrolyte storage tank for a redox flow battery system according to any one of claims 1 to 11, wherein the gas used in the redox flow battery system is bubbled through the liquid electrolyte in the electrolyte storage tank, stored therein and ultimately returned to the redox flow battery system.