Heat exchanger assembly
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- INVINITY ENERGY SYST (CANADA) CORP
- Filing Date
- 2026-01-30
- Publication Date
- 2026-08-06
Smart Images
Figure IB2026050891_06082026_PF_FP_ABST
Abstract
Description
[0001] HEAT EXCHANGER ASSEMBLY
[0002] FIELD OF THE INVENTION
[0003] The present invention relates to a heat exchanger assembly, in particularto a heat exchanger assembly for use in a battery module such as a redox flow battery module for example a vanadium redox flow battery module. The invention also relates to a battery system e.g. a redox flow battery system, comprising such a heat exchanger assembly, and a method of cooling using such a heat exchanger assembly.
[0004] BACKGROUND OF THE INVENTION
[0005] Redox flow battery systems typically comprise a plurality of redox battery modules. Typically, each battery module is housed in an enclosure , for example a container such as shipping container orsimilar, and comprises a cell stack with a shunt manifold, housing and associated structure. Each cell stack comprises a plurality of cell sub-stacks, usually 2 to 6, and typically 4 sub-stacks, and each of the sub-stacks comprises multiple cells connected to one another in a bipolar electrochemical cell arrangement, electrically in series, to increase output voltage. The battery module also comprises at least one tank pair comprising a tank for anolyte and a tank for catholyte, together with one or more pumps that circulate electrolyte from the tank(s), through the cell stack and back to the tank(s). There may be a separate tank pair for each cell stack but often a battery module comprising more than one cell stack contains a single tank pair shared between the cell stacks.
[0006] Effective thermal management is critical to the efficient use of battery modules and, in addition, the stability and solubility of the salts in the electrolyte may be affected by temperature. For example both the stability and the solubility of the vanadium salts used in vanadium reflux flow battery modules decreases as the temperature increases. For optimal performance,therefore, the anolyte and catholyte in the electrolyte tanks should be kept within a suitable temperature range, typically from about 5 ° to about 35 °C for a vanadium redoxflow battery module. Indeed, transferring any power, during normal operation(s), will yield stack l2R losses which produce heat in addition to pumping losses and shunt losses. Thus the main driverfor heating is operation of the cell stacks. However, as the electrolyte tanks are often housed with the other components of a battery module in a container, the electrolyte solutions may also be warmed by the heat generated by other parts of the battery module, for example the pumps used to circulate the electrolytes from the tanks to the cell stack and back to the tanks.
[0007] The stability of the electrolyte may be affected by an increase in temperature (Kazacos, 1990) (Kazacos, M.; Cheng, M.; Skyllas-Kazacos, M., Vanadium redox cell electrolyte optimisation studies. J. Appt. Electrochem.
[0008] 1990, 20,463-467), and, for example in a vanadium redox flow battery, it is desirable that the temperature of the electrolyte does not exceed 40 °C (Whitehead, 2005) (Whitehead, A. H.; Harrer, M.; Schreiber, M., Field test results for a 1 kW, 50 kWh vanadium redox flow battery. In EESAT 2005, San Francisco, CF, 2005; pp 41-42).
[0009] It is therefore advantageous for the battery module to include a means of cooling the electrolyte to ensure that it is kept at the optimal operating temperature and a number of documents describe redox flow battery modules, especially vanadium redox flow battery modules, in which the temperature of the electrolyte is controlled.
[0010] For example, Warshay, 1977 (Warshay, M.; Wright, L. O., Cost and size estimates for a redox bulk energy storage concept. J. Electrochem. Soc. 1977, 124 (2), 173-177) describes a redox flow battery module having heat exchangers for both the analyte and the catholyte. WC90 / 03666 relates to a vanadium redox flow battery module in which the electrolyte storage vessels may be equipped with temperature sensors to ensure that the electrolyte temperature does not exceed 40 °C and in which a heat exchanger may beincorporated in the catholyte flow loop to prevent excessive heating of the electrolyte. US5318865 relates to a flow battery module, especially a vanadium redox flow battery module, with a heat exchanger to control the decomposition and subsequent precipitation of the electrolyte. Hawkins, 2001 (Hawkins, J. M.; Robbins, T. P. In A field trial of a vanadium energy storage system, INTELEC 01, Edinburgh, UK, 18 October; IEEE: 2001; pp 652-656) describes a vanadium redox flow battery module having a hydraulic subsystem which includes a heat exchanger for cooling the electrolyte.
[0011] JP2002015762 relates to a redox flow battery in which, rather than being cooled, electrolyte solution is warmed to a temperature of about 30 to 45° C by blowing hot air over a pipe carrying the electrolyte solution.
[0012] More recent approaches to solving the problem of controlling the operational temperature of a redox flow battery module have included the inclusion of a heat exchanger in the cell stacks of a flow battery module as described in WO2013 / 044082. The redox flow battery described in WO2019 / 087377 comprises a plurality of cell stacks with a heat exchanger disposed above the cell stacks such that it cools the electrolyte supplied to each cell stack. A liquid coolant fluid is used in these heat exchangers.
[0013] However, arrangements such as these have the disadvantage of increasing the complexity and the manufacturing costs of the cell stacks.
[0014] In alternative systems, a heat transfer system may be provided between the outer surface of the electrolyte storage tanks and the inner surface of the container in which the battery module is housed. Such a system is described in WO2019 / 126381 , where the heat transfer system includes a plurality of air flow channels and an air circulation device.
[0015] Arrangements such as these in which the electrolyte is cooled by providing a flow of air across the walls of the electrolyte tanks mean that tanks with thin walls are required in order to provide satisfactory cooling. The maximum size of the electrolyte tanks is limited by the wall thickness, and this, in turn, limits the energy output of the battery module. Further, thinner wallsincrease the risk of leaks and reliance on secondary containment in such an eventuality. It would therefore be advantageous to provide an alternative means of cooling the electrolyte solutions within a battery module.
[0016] SUMMARY OF THE INVENTION
[0017] In a first aspect of the invention there is provided a heat exchanger assembly for use with a flow battery module, wherein the heat exchanger assembly comprises:
[0018] a fluid inlet;
[0019] one or more heat exchanger modules; and
[0020] means for moving fluid from the fluid inlet through said one or more heat exchanger modules;
[0021] wherein each heat exchanger module comprises:
[0022] one or more inlet openings, wherein said inlet openings are in fluid connection with the fluid inlet;
[0023] one or more outlet openings
[0024] one or more branch ducts connecting each of said one or more inlet openings to an outlet opening, wherein the branch ducts are configured (e.g. adapted and / or oriented and / or connected) to be submerged (e.g. at least partially, or substantially, or entirely) in an electrolyte of the flow battery module.
[0025] In a second aspect of the invention, there is provided a flow battery module comprising a container and, within the container:
[0026] at least one cell stack (e.g.in a power block unit);
[0027] at least one electrolyte tank;
[0028] means for pumping electrolyte from the at least one electrolyte tank to the cell stack;
[0029] optionally, means for electrically connecting the flow battery module; anda heat exchanger assembly for maintaining the temperature of the electrolyte in the at least one electrolyte tank at a desired temperature, characterised in that the heat exchanger assembly comprises:
[0030] a fluid inlet;
[0031] one or more heat exchanger modules; and
[0032] means for moving fluid from the fluid inlet through said one or more heat exchanger modules;
[0033] wherein each heat exchanger module comprises:
[0034] one or more inlet openings, wherein said inlet openings are in fluid connection with the fluid inlet;
[0035] one or more outlet openings
[0036] one or more branch ducts connecting each of said one or more inlet openings to an outlet opening, wherein the branch ducts are configured (e.g. adapted and / or oriented and / or connected) to be submerged (e.g. at least partially, or substantially, or entirely) in an electrolyte of the flow battery module.
[0037] In a third aspect of the invention there is provided a heat exchanger assembly for use with a flow battery module, wherein the heat exchanger assembly comprises:
[0038] a fluid inlet;
[0039] one or more heat exchanger modules;
[0040] an inlet duct connecting the fluid inlet to said one or more heat exchanger modules; and
[0041] means for moving fluid from the fluid inlet through said one or more heat exchanger modules;
[0042] characterised in that said inlet duct comprises a non-rigid material, and / or has a collapsible construction, and is connected in a (e.g. sufficiently) fluid-tight manner to said fluid inlet and said one or more heat exchanger modules.In a fourth aspect of the invention there is provided a flow battery module comprising a container and, within the container:
[0043] at least one cell stack (e.g.in a power block unit);
[0044] at least one electrolyte tank;
[0045] means for pumping electrolyte from the at least one electrolyte tank to the cell stack;
[0046] optionally, means for electrically connecting the flow battery module; and
[0047] a heat exchanger assemblyfor maintainingthe temperature of the electrolyte in the at least one electrolyte tank at a desired temperature, wherein the heat exchanger assembly comprises:
[0048] a fluid inlet;
[0049] one or more heat exchanger modules; and
[0050] an inlet duct connecting the fluid inlet to said one or more heat exchanger modules; and
[0051] means for moving fluid from the fluid inlet through said inlet duct and said one or more heat exchanger modules
[0052] characterised in that said inlet duct comprises a non-rigid material, and / or has a collapsible construction, and is connected in a (e.g. sufficiently) fluid-tight manner to said fluid inlet and said one or more heat exchanger modules.
[0053] ADVANTAGES OF THE INVENTION
[0054] The heat exchanger assembly of the invention has the advantage that gas such as air can be used as the coolant (heating) fluid and this reduces the complications associated with the use of liquid cooling or cooling systems that require secondary coolant loops.
[0055] Furthermore, since the heat exchanger assembly and flow battery module of the first and second aspects comprises heat exchanger modules in which, in use, the branch ducts are submerged in the electrolyte solution,the thickness of the walls, and therefore the size of the electrolyte tanks is not limited as it may be in systems where heat exchange ducts are provided in or adjacent the walls of the electrolyte tanks. Since the energy output of a battery module can be increased by increasing the volume of electrolyte flowing through the cell stacks, the heat exchanger assembly of the invention makes it possible to provide redox flow battery modules with an increased energy output compared to existing systems.
[0056] The heat exchanger assembly and flow battery module of the third and fourth aspects comprises an inlet duct connecting the fluid inlet to the one or more heat exchanger module. The inlet duct is non-rigid and / or has a collapsible construction, meaningthat, in an operational state, i.e. when coolingfluid is passingthrough the inlet duct, the fluid provides structure to the inlet duct such that it conforms at least partially to the internal configuration of the flow battery module. The inlet duct can thus be constructed such that, in operation, it conducts fluid to the one or more heat exchanger modules without impinging on other parts of the flow battery module. When the flow battery module is not operational, the inlet duct may be configured to collapse, e.g. partially or substantially, and / or at least partially close, limiting and / or preventing the flow of fluid. This is particularly advantageous in cold conditions as it limits unwanted cooling of the electrolyte. The non-rigid nature of the material forming the inlet duct in this embodiment also simplifies the formation of fluid tight connections with the fluid inlet and the heat exchanger modules.
[0057] BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a schematic view of a flow battery module comprising a heat exchanger assembly according to the invention.
[0058] FIGURE 2 is a schematic view of the heat exchanger assembly of the flow battery module of Figure 1 showing in greater detail the inlet duct and its connections to the air inlet and the heat exchanger modules.FIGURE 3 is a view of a heat exchanger module of the first aspect of the invention showing a series of branch ducts connected by a collar to a plate defining inlet and outlet openings.
[0059] FIGURE 4 shows a series of branch ducts connected at their ends by a connector.
[0060] FIGURE 5 is a section of the branch ducts of Figure 3.
[0061] FIGURE 6 is a schematic illustration of a process forforming a branch duct by twin sheet thermoforming.
[0062] FIGURE 7 is a schematic view of a flow battery module according to the invention showing in greater detail the air flow from the inlet of a heat exchanger assembly, through an inlet duct constructed from a flexible fabric and the heat exchanger modules and into the space above the electrolyte tanks of the flow battery module.
[0063] DETAILED DESCRIPTION OF THE INVENTION
[0064] As noted above, the invention relates in a first aspect to a heat exchanger assembly for use with a flow battery module, and in a second aspect to a flow battery module comprising a container and, within the container:
[0065] at least one cell stack (e.g. within a power block unit);
[0066] at least one electrolyte tank;
[0067] means for pumping electrolyte from the at least one electrolyte tank to the power block unit;
[0068] means for electrically connecting the flow battery module; and a heat exchanger assembly according to the first aspect of the invention.
[0069] In most cases, the heat exchanger assembly may be required to cool the electrolyte used in the flow battery module and the fluid entering at the fluid inlet of the heat exchanger assembly may be at the ambient temperature outside the module or may be cooled. In a few cases, if the battery module is being used in particularly cold conditions, the purpose ofthe heat exchanger assembly may be to warm the electrolyte and in such cases the fluid may be warmed before it passes through the heat exchanger assembly. The heat exchanger assembly may therefore in some cases comprise means for cooling and / or heating the fluid.
[0070] Suitably in the heat exchanger assembly, the fluid moved from the inlet to the outlet is a gaseous fluid e.g. air. In this case, the means for moving the fluid from the inlet to the outlet may be a fan. Suitably a fan is positioned at or adjacent to the air inlet. If cooling or warming the air is necessary, suitable means may be provided as described above.
[0071] When the heat exchanger assembly is installed in a flow battery module, the flow battery module suitably comprises one or more pairs of electrolyte tanks, for example one pair, of electrolyte tanks, each pair comprising an anolyte storage tank and a catholyte storage tank.
[0072] In a flow battery module accordingto the invention, the at least one electrolyte tank may be provided in the lower portion of the container housing and the at least one power block unit may be provided in the upper portion of the container housing. Suitably, in a flow battery module of this type, the fluid inlet of the heat exchanger assembly is positioned in the upper portion of the container housing, above the electrolyte tanks. For example, the inlet of the heat exchanger assembly may be provided in an air intake plenum housed in one wall of the container, suitably in the upper part of the container wall.
[0073] The fluid inlet may be connected to said one or more inlet openings of the heat exchanger modules via an inlet duct, which may be of a collapsible construction. For example, the inlet duct may comprise e.g. may be formed, partly or wholly, from a non-rigid material, for example a fabric, in particular a fluid impermeable fabric. The flexible material, e.g. fabric, may comprise a plastics material such as PVC tarpaulin (PVC coated or laminated polyester fabric). Other materials which may be used include urethane (or similar) coated nylon. The flexible material may also be a multi-layer composition ofmaterials mentioned herein. The plastics material may either form the entirety of the duct or may be provided as a coating on a fluid permeable fabric.
[0074] The inlet duct may be formed from (relatively) rigid portions of any suitable size and shape, interspersed with flexible joints of e.g. of flexible and / or non-rigid portions, so as to be configured in a collapsible manner.
[0075] The inlet duct may be formed partly or wholly from the non-rigid material but, suitably, the inlet duct is provided at its ends with collars via which it is sealably connected to the fluid inlet and to the one or more heat exchanger modules. In some cases, the collars may be formed from a semirigid or rigid e.g. plastics material such as polyethylene, polypropylene, PVDF, etc. Alternatively, the collars may be formed from a metal, which may be provided as a sheet or a mesh.
[0076] The advantages of providing an inlet duct of this type are discussed in greater detail below with reference to the heat exchanger assembly and the flow battery module of the third and fourth aspects of the invention.
[0077] When the heat exchanger assembly comprises two or more heat exchanger modules, a single inlet duct may be provided which connects the fluid inlet with the inlet openings of all of the heat exchanger modules. The use of a flexible material to form a part of or all of the inlet duct makes it a relatively simple matter for the inlet duct to be manufactured such that it sealably covers every inlet opening in every heat exchanger module of a heat exchanger assembly. As noted above, the inlet duct may be provided with collars which provide fluid-tight connections between the inlet duct and the fluid inlet and inlet openings. When the inlet duct is of collapsible construction, the collars suitably comprise a semi-rigid material such that when the heat exchanger assembly is not in operation, the inlet duct does not collapse at the points where it adjoins the fluid inlet and the inlet openings.Suitably, when the heat exchanger assembly is intended to be installed in a flow battery module, the heat exchanger module is constructed such that the branch ducts are adapted to be positioned in (e.g. within) the electrolyte tanks. More suitably, the branch ducts are adapted to depend (in other words be suspended) from the top of the electrolyte tanks into the electrolyte. More suitably, the branch ducts are adapted to be arranged (e.g. hung) in a generally or substantially vertical manner.
[0078] Suitably, the heat exchanger assembly comprises two or more heat exchanger modules, thereby providing at least one heat exchanger module for each electrolyte tank. More suitably, the heat exchanger assembly comprises from 2 to 12, still more suitably from 2 to 10, still more suitably from 2 to 8, still more suitably 4 to 8, for example 4 to 6, heat exchanger modules, thus providing 2 to 4, for example 1 , more suitably 2 or 3 heat exchanger modules for each electrolyte tank.
[0079] Suitably, a heat exchanger module comprises a plurality of inlet openings, from 2 to 12, still more suitably from 2 to 10, still more suitably 2 to 8 inlet openings, for example 2, 3, 4, 5 or 6 inlet openings. Since each inlet opening is connected to an outlet opening, there will be a corresponding number of outlet openings.
[0080] In the heat exchanger modules, the branch ducts may be connected to the one or more inlet openings and the one or more outlet openings via an inlet connector (e.g. a common, or shared, inlet connector) and / or an outlet connector (e.g. a common, or shared, outlet connector) respectively. One or both of the inlet connector and the outlet connector may be provided in the form of a collar into which the ends of the one or more branch ducts are fitted. In some cases, each heat exchanger module may comprise a plate in which the one or more inlet and one or more outlet openings are provided, and in this case, the inlet and outlet connectors may be housed in the plate. The plate may be sealed to the roof of the tank.The branch ducts may be in a U shape or a similar curved shape. More suitably, when each heat exchanger comprises a plate in which the inlet and outlet openings are provided, the branch ducts may be in a U shape or a similar curved shape such that the branch ducts protrude (e.g. depend in a downward direction) from one side of the plate.
[0081] When a heat exchanger module of this type is installed in a flow battery module, each of the electrolyte tanks of the flow battery module may be provided with a roof or cover having openings into each of which a plate of a heat exchanger module may be configured (e.g. adapted to fit) such that the branch ducts depend downwardly into the electrolyte tank and are submersed, at least in part, in the electrolyte solution.
[0082] Each branch duct comprises a passage through which cooling fluid such as air passes. Preferably, a plurality of branch ducts is connected to a single inlet opening and / or a single outlet opening, although this need not be the case. The greater the number of branch ducts, the greater the surface area available for heat exchange.
[0083] The branch ducts must be formed from material which is compatible with the electrolytes with which it will be used. For example if the heat exchange module is intended for use with a vanadium redox flow battery module in which the electrolytes comprise vanadium salts in sulfuric acid, it is important that the material from which the branch ducts are formed should not reactwith sulfuric acid. Suitable materials forformingthe branch ducts may include plastics such as polypropylene and polyethylene but may also include carbon materials or multilayer materials such as plastic lined metals. The ducts may be fabricated using any suitable method, for example twin sheet thermoforming, roto-molding, blow molding or injection molding. The method chosen will depend on the material from which the branch ducts are formed and on the number of passages in the branch duct. However, twin sheet thermoforming and injection moldingand especially twin sheet thermoforming processes are often particularly suitable.In some cases, each branch duct may be formed independently but in other cases several branch ducts may be formed as a single unit, for example by thermoforming a plurality of passages in two sheets of a plastics material.
[0084] As noted above, the outlet openings of each heat exchanger units may be provided in the same plate as the inlet openings.
[0085] The outlet openings of each heat exchanger unit may be connected to a fluid outlet (such as louvres on a wall or door of the container) of the heat exchanger assembly via an outlet duct, which is similar in nature to the inlet duct described above. However, in the majority of cases no outlet duct is necessary. For example, when the heat exchanger assembly is installed in a flow battery module and the cooling / heating fluid in the heat exchanger assembly is air, the outlet openings of each heat exchanger module may open into a space above the electrolyte tanks and may release air (i.e. cooling / heatingfluid) into this space such that the air may escape from the container of the battery module via vents in the container, e.g. via the roof, and / or rear, side and / or front walls, orfront doors, of the container, and / or via constructional holes if the container is not sealed. Therefore, preferably, the heat exchanger assembly is configured such that fluid exiting the heat exchanger assembly (e.g., exiting the one or more outlet openings) is vented to atmosphere.
[0086] In one or more embodiments, the battery module may comprise one to three power block units, each power block unit comprising a cell stack with an associated shunt manifold, and optionally a housing (or chassis) and associated structure (e.g. pipework).
[0087] In a third aspect, the invention relates to an alternative heat exchanger assembly for use with a flow battery module and in a fourth aspect to a flow battery module comprising a container and, within the container:
[0088] at least one cell stack (e.g. within a power block unit);
[0089] at least one electrolyte tank;means for pumping electrolyte from the at least one electrolyte tank to the power block unit;
[0090] means for electrically connecting the flow battery module; and a heat exchanger assembly according to the third aspect of the invention.
[0091] In the third and fourth aspects of the invention, the heat exchanger assembly comprises an inlet duct connectingthe fluid inlet to one or more heat exchanger modules and the inlet duct comprises a non-rigid material, and / or has a collapsible construction, and is connected in a (e.g. sufficiently) fluid-tight manner to said fluid inlet and said one or more heat exchanger modules.
[0092] Suitable non-rigid materials for use in the construction of the inlet duct comprise fabrics, in particular fluid impermeable fabrics. Such fabrics may comprise a plastics type material such as PVC tarpaulin (PVC coated or laminated polyester fabric), or urethane (or similar) coated nylon, or composites thereof. The plastics material may either form the entirety of the duct or may be provided as a coating on a fluid permeable fabric.
[0093] The inlet duct may be formed partly or wholly from the non-rigid material but, more suitably, the inlet duct is provided at its ends with collars via which it is sealably connected to the fluid inlet and to the one or more heat exchanger modules. In some cases, the collars may be formed from a semi-rigid plastics material such as polyethylene, polypropylene, PVDF, etc. Alternatively, the collars may be formed from a metal, which may be a sheet or a mesh.
[0094] The collapsible configuration of the inlet duct of this aspect of the invention suitably as a result of the flexibility of the material and / or components from which it is constructed provides certain advantages. When the heat exchanger assembly is in operation in a flow battery module, cooling fluid, for example air, is moved through the inlet duct, typically by a fan. The air pressure gives the inlet duct structure but the flexible nature of the material from which it is constructed makes it simple to ensure that it doesnot impinge on other parts of the flow battery module. Indeed, when inflated in operation the inlet duct may have a structured shape adapted to cooperate (e.g. occupy) the available space within an upper part of the container, e.g. it may be generally S-shaped in cross-section.
[0095] When the heat exchanger assembly is not in operation, there will be no fluid moving through the inlet duct and the pressure inside and outside the inlet duct will be equalized. The inlet duct will therefore be in a collapsed configuration. This may be particularly advantageous if coolingfluid is air and if the flow battery module is positioned in a cold environment. In this case, the electrolyte may not require cooling and passage of air through the heat exchanger assembly would lead to the electrolyte being cooled to below optimum operating temperature. However, if the inlet duct is in a collapsed configuration, ingress of air into the heat exchanger modules will be limited and, in some embodiments, substantially prevented.
[0096] The provision of collars at the ends of the inlet duct has the advantages firstly that, as described above, they assist with the sealable connection of the inlet duct to both the fluid inlet and to the one or more heat exchanger modules. However, in addition, the provision of the collar ensures that the ends of the inlet duct remain in a non-collapsed configuration even when the heat exchanger assembly is non-operational. This means that when the heat exchanger assembly is switched from non-operational to operational mode, movement of fluid can begin more quickly and easily.
[0097] As with the first and second aspects of the invention, the fluid moved from the inlet to the outlet is suitably a gas, particularly air and, the means for moving the fluid from the inlet to the outlet may be a fan, which is suitably positioned at or adjacent to the air inlet. If cooling or warming the air is necessary, suitable means may be provided as described above.
[0098] When the heat exchanger assembly is installed in a flow battery module, the flow battery module suitably comprises one or more pairs of electrolyte tanks as described for the first and second aspects of theinvention and, as with the first and second aspects of the invention, the electrolyte tank or tanks may be provided in the lower portion of the container housing and the at least one power block unit may be provided in the upper portion of the container. Suitably, in a flow battery module of this type, the fluid inlet of the heat exchanger assembly is positioned in the upper portion of the container, above the electrolyte tanks. For example, the inlet of the heat exchanger assembly may be provided in an air intake plenum housed in one wall of the container, suitably in the upper part of the container wall.
[0099] The heat exchanger modules of the heat exchanger assembly and the flow battery module of these aspects of the invention may be as described above for the first and second aspects.
[0100] The invention will now be described in greater detail, without limitation, with reference to the accompanying drawings.
[0101] Figure 1 is a schematic view of a flow battery module (10) mounted in a shipping container (not labeled) having a door, shown as being open in Figure 1 , provided with ventilation louvres (11 ). The flow battery module (10) has three power block units, each of which comprises a cell stack (12). Each cell stack (12) comprises four cell sub-stacks (13) and each cell sub-stack comprises a plurality of cells, usually between 40 and 60 cells. The cell stacks (12) are positioned above two electrolyte tanks (not shown). A pump (not shown) circulates electrolyte from the tanks via outer tubes (14, 15) near the outer walls in each tank, forming electrolyte inlet feeds via an inlet shunt manifold assembly, through the cell stacks (12) and an outlet shunt manifold assembly, and back to the tanks via return lines (not shown in figure 1 ). The return lines are typically formed as one or more vertical pipes in each tank near the front of the module (before a first heat exchanger module (20)). The inlet and outlet shunt manifold assemblies are conveniently here located underneath the cell stacks (12).In one or more preferred embodiments, the innertubes (114, 115) nearthe adjacent inner walls in each tank may form a balance line, also known as a hydraulic shunt connection, between the neighbouring tanks. In such embodiments, the innertubes extend from a front proximal end to a rear distal end of each tank and are preferably generally or substantially horizontal in use. The inner (114, 115) tubes are provided with apertures, preferably at a distal end thereof at the rear of each respective tank. Tubes 114, 115 are submerged below the expected free level of electrolyte in each tank. The proximalfront ends of each innertube (114, 115) are in fluid connection with each other via a U-shaped (when viewed from above) intermediate connecting tube (116) seen in Figure 7. Together, innertubes (114, 115) and intermediate connecting tube (116) provide a hydraulic shunt between the tanks. The length of the hydraulic shunt depends on the length of the tubes (114, 115, and 116). It will therefore be appreciated that the outer tube (14, 15) of one tank may be used in combination with the outer tube (14, 15) of the other tank, or one of the outer tube (14, 15) and innertube (114, 115) of one tank may be used with the other of the outer tube (14, 15) and innertube (114, 115) of the other tank, to provide a hydraulic shunt of greater or lesser length as desired. Nevertheless, the length, in this example, of the inner tubes 114, 115) between the distally located apertures at the remote ends of tubes 114, 115 provide a lengthy shunt channel between the tanks reducing shunt losses. The hydraulic shunt or balance line formed by tubes 114, 115 and 116 facilitates balancing of the electrolyte, and in particular level of the electrolytes between the tanks, as liquid electrolyte can flow in either direction between the tanks.
[0102] The battery module (10) is provided with a heat exchanger assembly comprising one or more heat exchanger modules 20. The heat exchanger assembly is shown in more detail in Figure 2. The heat exchanger assembly comprises an air inlet (17) within an air inlet plenum (16) set into the upper part of the container wall at the end opposite the door. The air inlet plenum(16) is provided with a fan (23), and is connected via an air inlet duct (18) to heat exchanger modules (20). In the battery module shown in Figures 1 and 2, there are six heat exchanger modules (20), three of which are in the anolyte tank and three in the catholyte tank.
[0103] The air inlet duct (18) is preferably of a collapsible construction and, in one or more embodiments formed from a flexible and / or collapsible material such as fabric (e.g. of PVC tarpaulin), which allows it to be positioned within the battery module in cooperation with (e.g. without impinging on) the space occupied by the electrolyte tanks or the power block unit. The use of a flexible material such as fabric to form the air inlet duct (18) has the additional advantage that a sufficiently airtight connection (see collar 32) can easily be formed between the air inlet duct and each of the heat exchanger modules (20).
[0104] A heat exchanger module (20) is shown in greater detail in Figures 3, 4 and 5. The heat exchanger module (20) comprises a plurality of branch ducts, here, U-shaped branch ducts (22). Each of the branch ducts has an inlet, which is connected to an inlet connector (24), and an outlet, which is connected to an outlet connector (26). In the embodiment of Figures 3 and 4, each inlet connector (24) and outlet connector (26) is connected to four branch ducts (22). The ends of the inlet connectors (24) and outlet connectors (26) for each heat exchanger module are housed in a plate (28) and define inlet openings (25) and outlet openings (27). In the embodiment of Figure 3, each plate (28) houses six inlet connectors (24) and six outlet connectors (26), and the inlet and outlet connectors (24, 26) are connected byfour branch ducts (22). In this embodiment, therefore, the heat exchanger module has 24 branch ducts (22). However, the number of branch ducts in each heat exchanger module (20) may vary depending on the amount of cooling (or heating) that is required. Increasingthe number of branch ducts (22) will increase the surface area for heat exchange. One or more relatively rigid shaped spacer clips 120 per module 20 may located at one side of ductsand / or between ducts 22 to provide a desired spacing and / or rigidity between sets of branch ducts 22 associated with each inlet and outlet connectors 24, 26. These facilitate groups of ducts 22 being consistently spaced and provide increased (e.g. maximum) heat exchange surface. Within each group of ducts 22, the inlet and outlet connectors may serve a similar purpose, or one or more additional spacer elements may be provided between one or more ducts, for example to keep one or more or each duct slightly separated from its neighbour.
[0105] As shown in Figure 5, the branch ducts (22) are not circular in cross section. This firstly means that the surface area available for heat exchange is larger than would be the case if, for example, the branch ducts (22) were circular in cross section. Also, however, the branch ducts are typically formed by well-known and inexpensive processes. One suitable method is twin sheet thermoforming in which two heated sheets of a plastics material such as polypropylene or polyethylene are placed in a two-part mold and then a vacuum is applied to the two parts of the mold and air pressure is applied between the sheets such that a branch duct is formed. This process is well known and is shown schematically in Figure 6. Other known methods of formingthe branch ducts (22) include roto-molding, blow molding and injection molding. Alternative materials may also be used to form the branch ducts (22), for example carbon materials or multi-layer materials such as metal lined with a plastics material. Such alternative materials may have improved heat transfer characteristics.
[0106] As shown in Figure 3 the plate (28) of the heat exchanger module fits into a cover (30), here a roof, of an electrolyte tank (40). The branch ducts (22) depend from the plate (28) into the electrolyte tank such that heat exchange can take place.
[0107] The inlet openings (25) are typically arranged in a first group, here a line, on one side of the plate (28) and the outlet openings (27) are arranged in a second group, here a line, on the other side of the plate (28) as shown inFigure 3. This means that an inlet duct (18) manufactured from a flexible fabric can be connected in a suitably airtight mannerto the plate such that air is supplied simultaneously to the inlets of all of the branch ducts (22) via the inlet openings (25). After the air has passed through the branch ducts (22) to cool (or heat) the electrolyte, it escapes via the outlet openings (27) into the space above the electrolyte tanks and is able to leave the container via any suitable outlet(s) within the container, for example via the ventilation louvres (11 ) in the door of the container. As shown in Figure 3, in the embodiment described, the air inlet duct (18) is here connected to all of the heat exchange modules of the battery module and this minimises the complexity, and therefore the manufacturing cost of the heat exchanger assembly of the invention.
[0108] The operation of the heat exchanger assembly is shown in Figure 7. The arrows shown in Figure 7 illustrate the movement of air through the heat exchanger assembly when in operation. The arrows indicate the air movement along the inlet duct (18) and into the set of three heat exchanger modules (20) which are shown in the figure. A similar flow of air passes along the inlet duct into the three heat exchanger modules at the other side of the flow battery module which are not shown in Figure 7.
[0109] Operation of the heat exchanger assembly is started by switching on the fan (23). This initiates a flow of airthrough the air inlet (17) into the air inlet duct (18) as indicated by arrow (50). The air inlet duct (18) is formed from a fabric and is of a collapsible construction and before operation begins, it is in a collapsed state. When the fan is switched on, the internal pressure within the air inlet duct (18) gives it structure as shown in Figure 7. Here a generally S-shaped, funnel type structure is shown with a taller first portion near inlet plenum 16 and a shorter second portion beneath cell stacks 12. In addition, the air inlet duct (18) has a first collar (30) at the point at which it is sealably connected to the air inlet plenum (16) and a series of second collars (32) at the points at which it is sealably connected to the inletopenings (25) of the heat exchanger modules (20). These prevent the inlet duct (18) from being collapsed along its whole length and assist in allowing it to adopt the required structure when the fan is switched on. The collars (30, 32) also provide sealable connections to the air inlet plenum (16) and the heat exchanger modules (20).
[0110] As shown by arrows (41 ) air passes through the collars (32) of the inlet duct (18) and into the inlet openings (25) of the heat exchanger modules (20). The air then passes through the branch ducts (22), which are submersed in the electrolyte solution, such that the air cools the electrolyte solution and becomes warmer as it travels towards the outlet openings (27). The arrows (44) show the air exiting the heat exchanger modules (20) via the outlet openings (27) and being vented into the upper portion of the container. The warmed air escapes the container via the ventilation louvres (11) shown in Figure 1 or via other openings in the container. The invention therefore provides an efficient means of cooling and / or heating the electrolyte in a redox flow battery module. The cooling and / or heating fluid may be air, which is significantly easier to handle than a separate cooling (or heating) liquid and does not cause environmental problems if there are leaks in the cooling / heating system. Furthermore, the heat exchanger modules are easy to manufacture using well-known processes such as twin vacuum sheet forming, roto-molding, blow molding or injection molding. In addition, the fact that the branch ducts of the heat exchanger modules are submerged (e.g. at least partially, or substantially or indeed entirely) in the electrolyte tanks means that they can be larger than if they were to be positioned in the cell sub-stacks or in the walls of the electrolyte tanks and this, in turn, means that a larger surface area is available for heat exchange such that the process is more efficient. Indeed, by being submerged, at least in part, in electrolyte, these are supported, and somewhat protected, by the electrolyte, particularly in this dependent (hanging) orientation. Otherorientations, which are also submerged in electrolyte, at least in part, may be used, but the dependent configuration is particularly advantageous.
[0111] The submerged heat exchanger module(s) (20) improve mixing of electrolyte within a respective tank by improving mixing, e.g. in a similar manner to baffles, for example due to convection flow that is encouraged. As a result of improved mixing, more, in some embodiments almost all, of the electrolyte in a respective tank is available for use as energy storage
[0112] The collapsible construction of the air inlet duct allows for easy assembly of the heat exchanger module as well as a lightweight construction of increased robustness. This is an advantage when the flow battery module is transported to a desired location. Furthermore, the collapsible construction of the inlet duct allows air to be prevented from entering the heat exchange modules when the heat exchanger assembly is not in operation, which can be an advantage when the ambient air temperature is very cold.
[0113] Further aspects and / or embodiments of the invention are described in the following clauses:
[0114] Clause 1. A heat exchanger assembly for use with a flow battery module, wherein the heat exchanger assembly comprises: a fluid inlet (16); one or more heat exchanger modules (20); and means for moving fluid from the fluid inlet (16) through said one or more heat exchanger modules (20); wherein each heat exchanger module (20) comprises: one or more inlet openings (25), wherein said inlet openings (25) are in fluid connection with the fluid inlet (16); one or more outlet openings (27); one or more branch ducts (22) connecting each of said one or more inlet openings (25) to an outlet opening (27), wherein the one or more branch ducts are configured to be submerged in an electrolyte of the flow battery module.
[0115] Clause 2. A heat exchanger assembly according to clause 1 wherein the fluid inlet is connected to said one or more inlet openings (25) via an inlet duct (18).Clause 3. A heat exchanger assembly according to clause 2 wherein the inlet duct (18) is of a collapsible construction and / or comprises a non-rigid material.
[0116] Clause 4. A heat exchanger assembly according to clause 2 or clause 3 wherein the inlet duct (18) connects the fluid inlet with the inlet openings (25) of all of said one or more heat exchanger modules (20).
[0117] Clause 5. A heat exchanger assembly for use with a flow battery module, wherein the heat exchanger assembly comprises: a fluid inlet; one or more heat exchanger modules; an inlet duct connecting the fluid inlettosaid one or more heat exchanger modules; and means for moving fluid from the fluid inlet through said inlet duct and said one or more heat exchanger modules; characterised in that said inlet duct comprises a non-rigid material, and / or has a collapsible construction, and is connected in a fluid-tight manner to said fluid inlet and said one or more heat exchanger modules.
[0118] Clause 6. A heat exchanger assembly according to clause 5 wherein each heat exchanger module (20) comprises: one or more inlet openings (25), wherein said inlet openings (25) are in fluid connection with the fluid inlet (16); one or more outlet openings (27); one or more branch ducts (22) connecting each of said one or more inlet openings (25) to an outlet opening (27), wherein the one or more branch ducts are configured to be submerged in an electrolyte of the flow battery module.
[0119] Clause 7. A heat exchanger assembly according to any one of clauses 1 to 6 wherein the fluid entering the fluid inlet (16) of the heat exchanger assembly is at the ambient temperature outside the module.
[0120] Clause 8. A heat exchanger assembly according to any one of clauses 1 to 6 further comprising means for cooling and / or heatingthe fluid.
[0121] Clause 9. A heat exchanger assembly according to any one of clauses 1 to 8 wherein the heat exchanger is configured to use a gaseous fluid such as air.Clause 10. A heat exchanger assembly according to clause 9 wherein the means for moving fluid from the inlet (16) to the outlet comprises a fan (23). Clause 11. A heat exchanger assembly according to clause 10 wherein the fan is positioned at or adjacent to the fluid inlet (16).
[0122] Clause 12. A heat exchanger assembly according to any one of the preceding clauses comprisingtwo or more heat exchanger modules (20). Clause 13. A heat exchanger assembly according to clause 12 comprising from 2 to 8 heat exchanger modules (20).
[0123] Clause 14. A heat exchanger assembly according to any one of clauses 1 to 4 or 6 to 13 wherein each heat exchanger module comprises 2 to 8 inlet openings (25).
[0124] Clause 15. A heat exchanger assembly according to any one of clauses 1 to 4 or 6 to 14 wherein, in the heat exchanger modules, the one or more branch ducts (22) are connected to the one or more inlet openings (25) and the one or more outlet openings (27) via an inlet connector (24) and an outlet connector (26) respectively.
[0125] Clause 16. A heat exchanger assembly according to clause 15 wherein one or both of the inlet connector (24) and outlet connector (26) is in the form of a collar into which the ends of the one or more branch ducts are fitted. Clause 17. A heat exchanger assembly according to any one of clauses 1 to 4 or 6 to 16 wherein each heat exchanger module comprises a plate (28) in which the inlet openings (25) and outlet openings (27) are provided.
[0126] Clause 18. A heat exchanger assembly according to clause 17 wherein one or both of the inlet connector (24) and outlet connector (26) are housed in the plate (28) and wherein the branch ducts (22) are in a U shape, or comprise a similar curved shape, such that the branch ducts protrude from one side of the plate.
[0127] Clause 19. A heat exchanger assembly according to any one of clauses 1 to 4 or 6 to 18 wherein a plurality of branch ducts is connected to a single inlet opening (25) and a single outlet opening (27).Clause 20. A heat exchanger assembly according to any one of clauses 3 to 19, wherein the inlet duct comprises a fluid impermeable fabric.
[0128] Clause 21. A heat exchange assembly accordingto any one of clauses 3 to 20, wherein the inlet duct is provided at its ends with collars via which it is sealably connected to the fluid inlet and to the one or more heat exchanger modules.
[0129] Clause 22. A heat exchanger assembly according to clause 21 , wherein the collars are formed from a semi-rigid plastic material and / or from a metal, which may be provided as a sheet or a mesh.
[0130] Clause 23. Aflow battery module comprising a container and, within the container: at least one cell stack; at least one electrolyte tank; means for pumping electrolyte from the at least one electrolyte tank to the cell stack; optionally, means for electrically connecting the flow battery module; and a heat exchanger assembly according to any one of clauses 1 to 22 for maintaining the temperature of the electrolyte in the at least one electrolyte tank at a desired temperature.
[0131] Clause 24. A flow battery module according to clause 23 wherein: the at least one electrolyte tank is provided in the lower portion of the container housing; the at least one cell stack is provided in the upper portion of the container housing; and wherein the fluid inlet of the heat exchanger assembly is positioned in the upper portion of the container housing, above the electrolyte tanks.
[0132] Clause 25. Aflow battery module accordingto clause 24 comprising one or more pairs of electrolyte tanks, wherein each pair comprises an anolyte storage tank and a catholyte storage tank.
[0133] Clause 26. Aflow battery module accordingto clause 25 comprising one pair of electrolyte tanks.Clause 27. A flow battery module according to clause 25 or clause 26 wherein the heat exchanger module is constructed such that the branch ducts are configured to be positioned in the electrolyte tanks.
[0134] Clause 28. A flow battery module according to clause T1 wherein the branch ducts are configured to depend from the top of the electrolyte tanks into the electrolyte.
[0135] Clause 29. A flow battery module according to clause 28 wherein each heat exchanger module comprises a plate in which the inlet and outlet openings are provided and wherein the branch ducts protrude from one side of the plate; each of the electrolyte tanks of the flow battery module is provided with a cover having openings into each of which a plate of a heat exchanger module may be configured such that the branch ducts depend downwardly into the electrolyte tank and are submersed, at least in part, in the electrolyte.
[0136] Clause 30. A flow battery module according to any one of clauses 23 to 29 wherein the heat exchanger assembly is configured to use a gaseous fluid and wherein the outlet ducts are configured to release the gaseous fluid into a space above the electrolyte tanks, and the container of the battery module is configured to allow gaseous fluid (e.g. air) to escape.
[0137] Clause 31. A heat exchanger assembly accordingto any one of clauses 1 to 22, wherein the fluid exiting the heat exchanger assembly (e.g., exiting the one or more outlet openings) is vented to atmosphere.
Claims
CLAIMS:
1. A heat exchanger assembly for use with a flow battery module, wherein the heat exchanger assembly comprises:a fluid inlet (16);one or more heat exchanger modules (20); andmeans for moving fluid from the fluid inlet (16) through said one or more heat exchanger modules (20);wherein each heat exchanger module (20) comprises:one or more inlet openings (25), wherein said inlet openings (25) are in fluid connection with the fluid inlet (16);one or more outlet openings (27);one or more branch ducts (22) connecting each of said one or more inlet openings (25) to an outlet opening (27), wherein the one or more branch ducts are configured to be submerged in an electrolyte of the flow battery module,wherein the heat exchanger is configured to use a gaseous fluid such as air.
2. A heat exchanger assembly according to claim 1 wherein the fluid inlet is connected to said one or more inlet openings (25) via an inlet duct (18).
3. A heat exchanger assembly according to claim 2 wherein the inlet duct (18) is of a collapsible construction and / or comprises a non-rigid material.
4. A heat exchanger assembly according to claim 2 or claim 3 wherein the inlet duct (18) connects the fluid inlet with the inlet openings (25) of all of said one or more heat exchanger modules (20).
5. A heat exchanger assembly for use with a flow battery module, wherein the heat exchanger assembly comprises:a fluid inlet;one or more heat exchanger modules;an inlet duct connecting the fluid inlet to said one or more heat exchanger modules; andmeans for moving fluid from the fluid inlet through said inlet duct and said one or more heat exchanger modules;characterised in that said inlet duct comprises a non-rigid material, and / or has a collapsible construction, and is connected in a fluid-tight manner to said fluid inlet and said one or more heat exchanger modules, wherein the heat exchanger is configured to use a gaseous fluid such as air.
6. A heat exchanger assembly according to claim 5 wherein each heat exchanger module (20) comprises:one or more inlet openings (25), wherein said inlet openings (25) are in fluid connection with the fluid inlet (16);one or more outlet openings (27);one or more branch ducts (22) connecting each of said one or more inlet openings (25) to an outlet opening (27), wherein the one or more branch ducts are configured to be submerged in an electrolyte of the flow battery module.
7. A heat exchanger assembly according to any one of claims 1 to 6 wherein the fluid entering the fluid inlet (16) of the heat exchanger assembly is at the ambient temperature outside the module.
8. A heat exchanger assembly according to any one of claims 1 to 6 further comprising means for cooling and / or heatingthe fluid.
9. A heat exchanger assembly according to any one of claims 1 to 8, configured such that fluid exiting the heat exchanger assembly (e.g., exiting the one or more outlet openings) is vented to atmosphere.
10. A heat exchanger assembly according to claim 9 wherein the means for moving fluid from the inlet (16) to the outlet comprises a fan (23).
11. A heat exchanger assembly according to claim 10 wherein the fan is positioned at or adjacent to the fluid inlet (16).
12. A heat exchanger assembly according to any one of the preceding claims comprising two or more heat exchanger modules (20).
13. A heat exchanger assembly according to claim 12 comprising from 2 to 8 heat exchanger modules (20).
14. A heat exchanger assembly according to any one of claims 1 to 4 or 6 to 13 wherein each heat exchanger module comprises 2 to 8 inlet openings (25).
15. A heat exchanger assembly according to any one of claims 1 to 4 or 6 to 14 wherein, in the heat exchanger modules, the one or more branch ducts (22) are connected to the one or more inlet openings (25) and the one or more outlet openings (27) via an inlet connector (24) and an outlet connector (26) respectively.
16. A heat exchanger assembly according to claim 15 wherein one or both of the inlet connector (24) and outlet connector (26) is in the form of a collar into which the ends of the one or more branch ducts are fitted.
17. A heat exchanger assembly according to any one of claims 1 to 4 or 6 to 16 wherein each heat exchanger module comprises a plate (28) in which the inlet openings (25) and outlet openings (27) are provided.
18. A heat exchanger assembly according to claim 17 wherein one or both of the inlet connector (24) and outlet connector (26) are housed in the plate (28) and wherein the branch ducts (22) are in a U shape, or comprise a similar curved shape, such that the branch ducts protrude from one side of the plate.
19. A heat exchanger assembly according to any one of claims 1 to 4 or 6 to 18 wherein a plurality of branch ducts is connected to a single inlet opening (25) and a single outlet opening (27).
20. A heat exchanger assembly according to any one of claims 3 to 19, wherein the inlet duct comprises a fluid impermeable fabric.
21. A heat exchange assembly according to any one of claims 3 to 20, wherein the inlet duct is provided at its ends with collars via which it is sealably connected to the fluid inlet and to the one or more heat exchanger modules.
22. A heat exchanger assembly according to claim 21 , wherein the collars are formed from a semi-rigid plastic material and / or from a metal, which may be provided as a sheet or a mesh.
23. Aflow battery module comprising a container and, within the container:at least one cell stack;at least one electrolyte tank;means for pumping electrolyte from the at least one electrolyte tank to the cell stack;optionally, means for electrically connecting the flow battery module; anda heat exchanger assembly according to any one of claims 1 to 22 for maintaining the temperature of the electrolyte in the at least one electrolyte tank at a desired temperature.
24. A flow battery module according to claim 23 wherein:the at least one electrolyte tank is provided in the lower portion of the container housing;the at least one cell stack is provided in the upper portion of the container housing; and whereinthe fluid inlet of the heat exchanger assembly is positioned in the upper portion of the container housing, above the electrolyte tanks.
25. Aflow battery module accordingto claim 24 comprising one or more pairs of electrolyte tanks, wherein each pair comprises an anolyte storage tank and a catholyte storage tank.
26. Aflow battery module accordingto claim 25 comprising one pair of electrolyte tanks.
27. A flow battery module according to claim 25 or claim 26 wherein the heat exchanger module is constructed such that the branch ducts are configured to be positioned in the electrolyte tanks.
28. A flow battery module according to claim 27 wherein the branch ducts are configured to depend from the top of the electrolyte tanks into the electrolyte.
29. A flow battery module according to claim 28 wherein each heat exchanger module comprises a plate in which the inlet and outlet openings are provided and wherein the branch ducts protrude from one side of the plate;each of the electrolyte tanks of the flow battery module is provided with a cover having openings into each of which a plate of a heat exchanger module may be configured such that the branch ducts depend downwardly into the electrolyte tank and are submersed, at least in part, in the electrolyte.
30. A flow battery module according to any one of claims 23 to 29 wherein the heat exchanger assembly is configured to use a gaseous fluid and wherein the outlet ducts are configured to release the gaseous fluid into a space above the electrolyte tanks, and the container of the battery module is configured to allow gaseous fluid (e.g. air) to escape.