Flow battery

Abstract

The flow battery includes a first conductive plate and a second conductive plate. Each of the first and second conductive plates has a corrugated surface formed with a plurality of first corrugations extending along a first axis of the conductive plate and a plurality of second corrugations extending along a perpendicular second axis of the conductive plate. A first conductive plate and a second conductive plate are arranged to form a first battery cell of a flow battery, the respective corrugated surfaces of the first and second conductive plates provide a cathode and a corresponding anode of the first cell, respectively, and define opposing walls of an electrolyte flow path between the first and second conductive plates.

Description

Technical Field

[0001] The present invention relates to batteries and more particularly, but not exclusively, to flow batteries. Background Art

[0002] In a flow battery such as that disclosed in US2013 / 0037760 A1, charged anolyte and catholyte are provided to the battery cells of the battery during use, while depleted anolyte and catholyte are removed from the battery cells. This arrangement provides the advantage of being able to conveniently "recharge" the flow battery by replacing depleted electrolyte with charged electrolyte. Further advantages of flow batteries are that the electrolyte is typically non-volatile and the battery cells have a long life. While such batteries are suitable for a variety of applications requiring power storage, they may have particular advantages in electric vehicles, for example, the process of replacing depleted electrolyte may be faster than charging a conventional electric vehicle battery. However, flow batteries may have a relatively high mass and a relatively high energy density compared to other batteries conventionally used in electric vehicles. Summary of the invention

[0003] The present invention aims to alleviate the above problems. In addition, the present invention also aims to provide an improved liquid flow battery and an improved electric vehicle

[0004] According to a first aspect, a flow battery is provided, the flow battery comprising a first conductive plate and a second conductive plate. The first conductive plate and the second conductive plate each comprise a corrugated surface, the corrugated surface being formed with a plurality of first corrugations extending along a first axis of the conductive plate and a plurality of second corrugations extending along a second non-parallel axis of the conductive plate. The first conductive plate and the second conductive plate are arranged to form a first battery cell of the flow battery, in which the corrugated surfaces of the first conductive plate and the second conductive plate respectively provide a cathode and a corresponding anode of the first battery cell and define opposite walls of an electrolyte flow channel between the first conductive plate and the second conductive plate.

[0005] Having corrugations along two different axes can increase the contact area between the plate and the electrolyte relative to the footprint of the plate, thereby achieving a more efficient battery design in specific embodiments. For example, a flow battery according to an embodiment includes corrugated anode surfaces and cathode surfaces that provide a larger surface area in the xy plane than the nominal area. So configured, the flow battery according to these embodiments can have a higher power density than a similar arrangement with a planar anode surface and a planar cathode surface. Therefore, the flow battery according to these embodiments can be smaller and lighter than a prior art battery with an equivalent power output. The flow battery according to this embodiment can be used in a range of applications. For example, it can be used for home or industrial off-grid energy storage, or for electric vehicles.

[0006] Those skilled in the art will appreciate that the flow battery can also charge (or recharge) the electrolyte by connecting the flow battery to an appropriate power source and reversing the flow of the electrolyte through one or more cells of the flow battery. For example, for an electric vehicle, a conventional existing electric vehicle charging system in a home, workplace or commercial setting can therefore be used to recharge the depleted electrolyte. Thus, a flow battery according to the present invention can be used to produce a charged electrolyte. This may be particularly advantageous for storing electricity generated by renewable energy sources in remote locations (e.g., electricity generated by offshore wind farms, tidal or wave power generation, or solar panel arrays).

[0007] The electrolyte may flow between the electrolyte inlet and the electrolyte outlet. For example, a charged anolyte may be provided to the cell via the anolyte inlet, and depleted anolyte may be removed from the cell via the anolyte outlet. A charged catholyte may be provided to the cell via the catholyte inlet, and depleted catholyte may be removed from the cell via the catholyte outlet. The battery may include at least one charged electrolyte tank. There may be a charged anolyte tank. There may be a charged catholyte tank. There may be a depleted anolyte tank. There may be a depleted catholyte tank.

[0008] The footprint of the first conductive plate may be area A1. It will be appreciated that where the plate has a rectangular planar shape, the footprint of the plate will be the product of the straight length and width of the rectangle (i.e., length x width). The surface area of ​​the first conductive plate may be area SA1. It will be appreciated that SA1>A1. It may be SA1>110%A1. SA1 may be between 110% and 150% of the size of A1. For example, SA1 may be approximately 110%, 120%, 130%, 140%, or 150% of A1.

[0009] The footprint of the second conductive plate may be area A2. It will be appreciated that in the case where the plate has a rectangular planar shape, the footprint of the plate will be the product of the straight length and width of the rectangle (i.e., length x width). The surface area of ​​the second conductive plate may be area SA2. It will be appreciated that SA2>A2. It may be SA2>110%A2. SA2 may be between 110% and 150% of the size of A2. For example, SA2 may be approximately 110%, 120%, 130%, 140%, or 150% of A2. In most embodiments, A1=A2. It may also be SA1=SA2.

[0010] The corrugation geometry along the first axis may be different from the corrugation geometry along the second axis. For example, the number of peaks and / or valleys per unit length may be different. The second axis may be perpendicular to the first axis.

[0011] Each plate may have a theoretical central plane containing both the first axis and the second axis, with the width and length of the plate extending in the plane and the thickness of the plate being perpendicular to the plane.

[0012] The corrugated surface of at least one of the first and second conductive plates, preferably both, may include a plurality of first peaks and valleys extending along the first axis of the conductive plate, and a plurality of second peaks and valleys extending along the second axis of the conductive plate.

[0013] The distance between a peak in the plurality of first peaks and valleys and an adjacent valley is different from the distance between a peak in the plurality of second peaks and valleys and an adjacent valley, for example, differing by at least 20%, preferably by more than 50%. Where such corrugations are present, the average number of peaks and valleys per unit length along the second axis may be greater than the average number of peaks and valleys per unit length along the first axis.

[0014] The first conductive plate and the second conductive plate may be arranged such that the first axes of the first conductive plate and the second conductive plate are oriented substantially parallel to the flow axis along which the electrolyte flows through the electrolyte flow channel. In this case, preferably, the distance between a peak and an adjacent valley in the plurality of first peaks and valleys along the first axis is greater than the distance between a peak and an adjacent valley in the plurality of second peaks and valleys along the second axis.

[0015] The area defined between the first plate and the second plate can be considered as a tessellation of 3-D shapes, each shape having a similar 3D shape, such as the general form of a polyhedron. The tessellation can generally be in the form of a rectangle or square. The tessellation can generally be in the form of a hexagon. The form of the tessellation can be more complex, effectively combining two or more different 3D shapes. The 3D shape can be at least partially curved.

[0016] The first and second conductive plates are constructed and arranged such that a flow path between the conductive plates in the general direction of the first axis is less tortuous than a flow path between the conductive plates in the general direction of the second axis.

[0017] The area defined between the first plate and the second plate is shaped so that the general path between the plates along the general direction of the first axis (e.g., the flow axis) is less tortuous than the general path between the plates along the general direction of the second axis (e.g., perpendicular to the flow axis). This can help promote the flow of electrolyte between the plates while still ensuring that there is a larger contact surface area between the electrolyte and the plates.

[0018] The tortuosity of the corrugated shape in a given direction (for example, along the first axis or the second axis) can be defined as the ratio of the distance between peaks and valleys in the direction of a third axis (the third axis is perpendicular to the first axis and the second axis) to the distance between adjacent peaks in the given direction.

[0019] In other words, taking a cross-sectional segment from one peak to another in a plane containing a given direction and a third axis, the measure of tortuosity may be a measure of the deviation from a straight line extending between the peaks.

[0020] The tortuosity of the shape of the first plate and / or the second plate along the first axis (e.g., the flow axis) can be a ratio in the range of 1:2 (i.e., more tortuous) to 1:40 (i.e., not very tortuous), preferably a ratio in the range of 1:8 to 1:16, and optionally a ratio in the range of 1:6 to 1:25.

[0021] The tortuosity of the shape of the first plate and / or the second plate along the second axis (e.g., perpendicular to the flow axis) can be a ratio in the range of 1:1.5 (i.e., more tortuous) to 1:25 (i.e., less tortuous), preferably a ratio in the range of 1:3 to 1:12, and optionally a ratio in the range of 1:2 to 1:20.

[0022] Preferably, according to this measurement standard, the shape of the first plate and / or the second plate along the first axis is not as tortuous as the shape of the first plate and / or the second plate along the second axis, for example, so that the above ratio for the first axis is approximately 150% to 300% of the ratio for the second axis, optionally approximately 200% (i.e., approximately twice the ratio).

[0023] In one embodiment, for example, the tortuosity of the shapes of the first and second plate surfaces along the second axis (e.g., perpendicular to the flow axis) is a ratio of 1:6, while the tortuosity measured along the first axis (e.g., the flow axis) is a ratio of 1:12.

[0024] Thus, the corrugations along a first axis of the conductive plate may be longer (less tortuous) than the corrugations along a second axis of the plate. If the corrugations along the electrolyte flow axis are too dense (or too tortuous), this may adversely affect the flow of electrolyte through the battery cell. Therefore, it may be advantageous to provide tighter and / or more tortuous corrugations in an axis of the plate that is generally perpendicular to the general direction of electrolyte flow.

[0025] The conductive plate may include a third axis oriented substantially perpendicular to a plane defined by the first axis and the second axis. The distances between peaks and valleys along the third axis may be substantially equal for peaks and valleys spaced apart along the first axis and for peaks and valleys spaced apart along the second axis. In some embodiments, the distances between peaks and valleys along the third axis may be different for different adjacent peaks and valleys along the first axis. The distances between peaks and valleys along the third axis may be different for different adjacent peaks and valleys along the second axis.

[0026] The peaks and valleys are preferably evenly spaced along the first axis. The peaks and valleys are preferably evenly spaced along the second axis. Preferably, each plate is shaped such that any cross section parallel to the first axis and perpendicular to the second axis and within an area extending across a majority of the distance of the plate along the second axis, and preferably along at least 80% of the distance, contains a plurality of corrugations (e.g., at least two peaks and at least two valleys). Preferably, each plate is shaped such that any cross section parallel to the second axis and perpendicular to the first axis and within an area extending across a majority of the distance of the plate along the first axis, and preferably along at least 80% of the distance, contains a plurality of corrugations (e.g., at least two peaks and at least two valleys).

[0027] The maximum slope relative to a nominal neutral plane (which extends in the direction of the first axis and the second axis and may be the same as the theoretical center plane mentioned above) may be different for a cross section taken about a first plane (which is perpendicular to the neutral plane and contains the first axis) than for a cross section taken about a second (e.g., perpendicular) plane (which is perpendicular to the neutral plane and contains the second axis) relative to the nominal neutral plane. In an embodiment, the magnitude of the maximum slope of the corrugated surface between peaks and valleys in the direction along the first axis may be different (e.g., greater than 20%, possibly greater than 50%) than the magnitude of the maximum slope of the corrugated surface between peaks and valleys in the direction along the second axis. The ratio of the larger maximum slope to the smaller maximum slope may be in the range of 1.5:1 to 20:1, may be greater than 2:1, and may be greater than 4:1.

[0028] Preferably, the maximum slope of the corrugated surface between peaks and valleys in the direction along the flow axis (e.g., the first axis) is less than the maximum slope of the corrugated surface between peaks and valleys in the transverse (e.g., vertical) direction (e.g., the second axis). In an embodiment, preferably, the magnitude of the maximum slope of the anode surface and the cathode surface is greatest in a direction substantially perpendicular to the electrolyte flow direction. Providing the conductive plate with a decreasing slope in the direction of the fluid flow axis helps ensure that the electrolyte flow along the flow axis is optimized.

[0029] At least one of the first conductive plate and the second conductive plate may be a corrugated plate having corrugated surfaces on opposite sides thereof. Both conductive plates may be corrugated plates. The corrugated plates may have a substantially uniform thickness.

[0030] The locations of the peaks of the corrugated surface on a first side of the conductive plate may correspond to the locations of the valleys of the corrugated surface on a second, opposite side of the conductive plate. The locations of the valleys of the corrugated surface on a first side of the conductive plate may correspond to the locations of the peaks of the corrugated surface on a second, opposite side of the conductive plate.

[0031] The flow battery may include a third conductive plate, wherein the first conductive plate, the second conductive plate, and the third conductive plate each include a corrugated plate having corrugated surfaces on opposite sides of the corrugated plate. For example, the second conductive plate and the third conductive plate may be arranged to form a second battery cell of the flow battery, in which the corrugated surfaces of each of the second conductive plate and the third conductive plate provide a cathode and a corresponding anode of the second battery cell and define opposing walls of an electrolyte flow channel between the second conductive plate and the third conductive plate. In this arrangement, the second conductive plate thus forms an anode of one of the first battery cell and the second battery cell and a cathode of the other of the first battery cell and the second battery cell.

[0032] The third conductive plate may be substantially the same in shape and / or structure as the first conductive plate or the second conductive plate. The flow battery may in principle comprise any number of conductive plates arranged to provide any number of battery cells, each battery cell being formed by at least the opposing corrugated surfaces of two conductive plates providing the cathode and corresponding anode of the battery cell and defining opposing walls of an electrolyte flow channel between the two conductive plates.

[0033] The conductive plate can be formed by a conductive composite material, the material comprising a polymer and conductive filler particles. The filler particles can be roughly evenly distributed throughout the polymer. The conductive composite forms a conductive polymer core of the conductive plate. Suitable polymer examples include acrylonitrile-butadiene-styrene (ABS), polysulfone (PSU), polyethersulfone (PESU) and polyphenylsulfone (PPSU). Suitable conductive filler particle examples include carbon fibers, carbon nanotubes, graphene, carbon, fullerene or any other carbonaceous material, semiconductor material or metal substance. The conductive filler can include a material coated with a metal, a metal alloy, a semiconductor mineral or an oxide. The conductive filler can alternatively or additionally include metal fibers or powders. Examples of suitable metals include gold, nickel, copper, lead, tin, iron, cobalt, magnesium, zinc, titanium, silver, aluminum or alloys of these metals. The diameter of the conductive filler particles can be up to 50 μm, typically between 7 μm and 10 μm. The volume percentage of the conductive filler particles in the conductive composite material can be between 2% and 50%, but typically between 20% and 30%. The conductive plates may be formed by injection molding, compression molding, or other manufacturing processes such as additive manufacturing or 3D printing.

[0034] The conductive plates may alternatively be manufactured by superimposing a non-conductive material with a conductive mesh or grid structure.

[0035] The anode and cathode surfaces of the conductive plates may be formed by cold coating techniques, vapor deposition, electroplating, sputtering, or other methods of depositing metal onto a substrate (eg, a conductive composite material or a conductive polymer core).

[0036] The anode surface and the cathode surface may comprise different materials. The anode surface or the cathode surface may comprise one or more of the following elements: Fe, Mg, Ca, Zn, Al, Na, Ni, which may be in pure form or in alloy form. Alternatively or additionally, the anode surface or the cathode surface may be provided by a non-metallic material, which may comprise one or more of C, Si or any other suitable anode or cathode material.

[0037] The flow battery can be configured to define a cathode electrolyte flow channel adjacent to the cathode surface and an anolyte flow channel adjacent to the anode surface. The flow battery can include one or more pumps for pumping cathode liquid along the cathode electrolyte flow channel in a first flow direction and pumping anode liquid along the anode electrolyte flow channel in a second flow direction. The first flow direction and the second flow direction can be substantially parallel but in opposite directions.

[0038] The flow battery may include a diaphragm between the first conductive plate and the second conductive plate. The diaphragm, which is permeable to anions and cations during battery charge and discharge, may be formed from a permeable polymer such as polypropylene, cellulose. In some embodiments, the diaphragm may include a glass fiber reinforcement. For example, the diaphragm may include a polymer sold under the trade name "Nafion", or other suitable ion exchange membrane materials available to the skilled person.

[0039] Such a flow battery may be configured with a cathode liquid flow path located between the cathode surface and the separator on a first side of the separator and an anolyte liquid flow path located between the anode surface and the separator on an opposing second side of the separator.

[0040] In an embodiment, the electrolyte flow channel may include a cathode electrolyte flow channel and an anolyte flow channel separated by a membrane. However, in other embodiments, regarding what can be described as a "membrane-free structure", the cathode and anode define opposing walls of a single electrolyte flow channel. These embodiments may include arrangements for controlling mixing of the anolyte and the catholyte by co-laminar flow or using immiscible liquids.

[0041] If provided, the diaphragm may be substantially planar. If provided, the diaphragm may be formed with a plurality of first corrugations extending along a first axis of the diaphragm, and a plurality of second corrugations extending along a perpendicular second axis of the diaphragm. The corrugations formed in the diaphragm are complementary in shape to the corrugated surface of at least one of the first and second conductive plates. The diaphragm may be arranged such that the peaks of the corrugated surface of the diaphragm are contained in the valleys of the corrugated surface of at least one of the first and second conductive plates. The diaphragm may be arranged such that the peaks of the corrugated surface of at least one of the first and second conductive plates are contained in the valleys of the corrugated surface of the diaphragm. The diaphragm may be arranged such that the peaks of the corrugated surface of the diaphragm (e.g., at least a majority of the peaks, optionally all of the peaks) are contained in the valleys of the corrugated surface of one or all of the first and second conductive plates. The diaphragm may be arranged such that valleys (e.g., at least most of the valleys, optionally all of the valleys) of the corrugated surface of the diaphragm are contained within the peaks of the corrugated surface of one or all of the first and second conductive plates. The diaphragm may have a shape that follows the peaks and valleys of both the first and second conductive plates, for example in a manner that matches the shape of the peaks and valleys of the first plate and follows the shape of the peaks and valleys of the second plate. In the case where the battery comprises a plurality of battery cells formed from a plurality of corrugated conductive plates, a corrugated membrane may be provided between each corrugated conductive plate.

[0042] The diaphragm can be held in place using a grid structure. In the case where the diaphragm is generally planar, the grid structure can also be generally planar. If the diaphragm has a corrugated shape, the grid structure can also contain corrugations or be formed in some other way to maintain the corrugated shape of the diaphragm. The grid structure can be formed with a plurality of corrugations that are complementary to the corrugated shape formed in the diaphragm. The surface of the diaphragm is supported on the grid structure. The peaks of the grid structure are accommodated in the valleys on the surface of the diaphragm. The peaks on the surface of the diaphragm are accommodated in the valleys of the grid structure. The grid structure can be used as a support structure that fixes the diaphragm in place, thereby preventing the diaphragm from contacting the anode or cathode. The grid structure can hold the diaphragm at a predetermined distance from the anode and cathode to achieve effective ion exchange. The grid structure can be composed of a non-conductive inert material, which can be a polymer, which can be acrylonitrile butadiene styrene, polyphenylene sulfide, or any other polymer that remains inert in the chemical environment of the flow battery cell.

[0043] The flow batteries described and claimed herein can be relatively light and have relatively high power density. For example, the flow batteries of the present invention can deliver at least 320 watt-hours of energy per liter of electrolyte, which makes the flow batteries particularly attractive in a range of applications requiring energy storage.

[0044] The first battery cell may include: a battery cell inlet, through which electrolyte is provided to the battery cell; and a battery cell outlet, through which electrolyte leaves the battery cell. The corrugated surfaces of the first and second conductive plates may be configured so that the electrolyte flow channel changes direction in the xy plane between the battery cell inlet and the battery cell outlet. Alternatively or additionally, the corrugated surfaces of the first and second conductive plates may be configured so that two or more electrolyte flow channels are provided between the battery cell inlet and the battery cell outlet. The corrugated surface may include a serpentine, parallel serpentine, spiral, spiral serpentine, leaf-integrated, parallel Murray branches, mesh-integrated or leaf-shaped surface. The corrugated surface may define flow areas or flow channels that are serpentine, parallel serpentine, spiral, spiral serpentine, leaf-integrated, parallel Murray branches, mesh-integrated or leaf-shaped.

[0045] According to a second aspect, there is provided an electric or hybrid vehicle comprising a flow battery according to the first aspect.

[0046] The electric or hybrid vehicle may be an electric road vehicle, a watercraft, an aircraft, a spacecraft or any other type of electric vehicle such as an electric scooter, an electric bicycle etc. In such a vehicle, according to the first aspect, there may be one or more flow batteries configured to provide electricity for propelling the vehicle or to assist in the propulsion of the vehicle and preferably be the main power source for the vehicle.

[0047] The present invention also provides a method for refueling the above-mentioned vehicle. This method may include extracting depleted electrolyte from the vehicle using a pump at a charging station; and using a pump at the charging station, which may be the same pump or a different pump, supplying charged electrolyte to the vehicle. In the case where the electric vehicle is an electric road vehicle, the infrastructure for refueling the vehicle can therefore be very similar to today's (petrol / diesel) gas stations, and can allow the use of existing gas stations to be changed. However, it should be understood that the flow battery can also be recharged by connecting the flow battery to an appropriate power source and by causing the electrolyte to flow in reverse through the battery cell (one or more). It should be understood that the vehicle typically includes one or more tanks for containing depleted electrolyte and one or more tanks for containing charged electrolyte. One or more flow batteries can share a common tank. For example, there may be multiple charged cathode electrolyte tanks that provide electrolyte for a larger number of flow batteries and / or flow battery cells.

[0048] Of course, it will be appreciated that features described with respect to one aspect of the invention may be incorporated into other aspects. For example, the method may incorporate any features described with reference to a flow battery, and vice versa.

[0049] According to a third aspect, a conductive plate for a liquid flow battery is provided, wherein the conductive plate can be formed by a conductive composite material, wherein the conductive composite material includes: a polymer; and conductive filling particles, wherein the conductive filling particles are roughly uniformly distributed throughout the polymer, wherein the conductive composite material forms a conductive polymer core of the conductive plate, and wherein the conductive plate includes a corrugated surface, wherein the corrugated surface is formed with a plurality of first corrugations extending along a first axis of the conductive plate, and a plurality of second corrugations extending along a perpendicular second axis of the conductive plate.

[0050] The conductive polymer core may include an anode surface and a cathode surface on opposing surfaces, such as a corrugated anode surface and a corrugated cathode surface.

[0051] The polymer may include one or more of acrylonitrile butadiene styrene (ABS), polysulfone (PSU), polyethersulfone (PESU), or polyphenylene sulfide (PPS).

[0052] The conductive filler particles may include one or more of carbon fibers, carbon nanotubes, graphene, carbon, fullerenes, or any other carbonaceous material, semiconductor, or metallic substance.

[0053] The conductive filler particles may include materials coated with metals, metal alloys, semiconductor minerals, or oxides.

[0054] The conductive filler particles may include metal fibers or powders.

[0055] The conductive filler particles may include gold, nickel, copper, lead, tin, iron, cobalt, magnesium, zinc, titanium, silver, aluminum, or alloys of one or more of these metals.

[0056] The electrically conductive filler particles may have a diameter of up to 50 μm, for example typically between 7 μm and 10 μm.

[0057] The conductive composite material may include between 2% and 50% by volume, but typically between 20% and 30% conductive filler particles.

[0058] The conductive plates may be formed by injection molding, compression molding, or other manufacturing processes such as additive manufacturing or 3D printing.

[0059] The conductive plates may alternatively be manufactured by superimposing a non-conductive material with a conductive mesh or grid structure.

[0060] The anode and cathode surfaces of the conductive plates may be formed by cold coating techniques, vapor deposition, electroplating, sputtering or other methods of depositing metal onto the conductive composite material.

[0061] The anode surface and the cathode surface may comprise different materials.

[0062] The anode surface or cathode surface may include one or more of the following elements: Fe, Mg, Ca, Zn, Al, Na, Ni, which may be in pure form or in alloy form.

[0063] The anode surface or cathode surface may be provided by a non-metallic material, which may include one or more of C, Si or any other suitable anode material or cathode material.

[0064] The conductive plates may be bipolar plates.

[0065] The conductive plate of the third aspect may include one or more of the optional features of the conductive plate of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Embodiments will now be described, by way of example only, with reference to the accompanying schematic drawings, in which:

[0067] Figure 1is a schematic diagram of a flow battery according to a first embodiment.

[0068] Figure 2 Yes Figure 1 Schematic diagram of a flow battery electric vehicle.

[0069] Figure 3 yes Figure 1 Schematic diagram of the two battery cells of the flow battery.

[0070] Figure 4 Shown separately Figure 1 The bipolar plates of the battery.

[0071] Figure 5 It is cut along the length of the bipolar plate Figure 3 Cross-sectional view of the bipolar plate.

[0072] Figure 6 It is cut along the width direction of the bipolar plate Figure 3 Cross-sectional view of the bipolar plate.

[0073] Figure 7 is a schematic diagram showing a battery cell of a flow battery according to a second embodiment.

[0074] Figure 8 It is shown Figure 7 Schematic diagram of the separator of a battery cell and the polymer grid structure on which the separator is mounted.

[0075] 9A to 9D shows examples of some corrugation shapes that may form conductive plates of a battery according to an embodiment of the present invention; and

[0076] FIG. 10A to FIG. 10D An example of an electrolyte flow pattern in a battery flow cell according to the present invention is shown. Specific embodiments

[0077] exist Figure 1 Schematically shows a flow battery 1 according to an embodiment. The flow battery 1 includes at least one battery cell. In the illustrated embodiment, the flow battery 1 includes six battery cells 11-16, but it should be understood that any suitable number of battery cells may be used, such as one, two, three, four, five, seven or any number of battery cells.

[0078] The flow battery 1 includes a charged anolyte storage tank 20, a charged catholyte storage tank 30, a depleted anolyte collector 21, and a depleted catholyte collector 31. The battery 1 is configured such that: in use, the charged anolyte tube 22 and the charged catholyte tube 32 provide the battery cells 11-16 with charged anolyte and charged catholyte, respectively. The depleted anolyte is removed from the battery cells 11-16 and supplied to the anolyte collector 21 through the depleted anolyte tube 23. Also, the depleted catholyte is removed from the battery cells 11-16 and supplied to the catholyte collector 31 through the depleted catholyte tube 33.

[0079] The battery 1 has a positive terminal 17 and a negative terminal 18 for connection to an electrical load. The flow battery 1 is particularly suitable for use in an electric vehicle 100, such as Figure 2 As shown. For example, the flow battery 1 can be retrofitted to replace the power system in the existing power system space of an internal combustion engine or electric vehicle. In order to recharge the electric vehicle 100, it is necessary to remove the depleted anolyte and catholyte from the collector 21 and the collector 31, and provide the charged anolyte and catholyte to the storage tank 20 and the storage tank 30. However, the flow battery 1 can in principle be used for any suitable power storage application.

[0080] like Figure 3 As shown, each battery cell 11-16 includes a first conductive plate 52 and a second conductive plate 53. The first conductive plate 52 and the second conductive plate 53 provide a cathode surface 52 and an anode surface 53, respectively. Each of the first conductive plate 52 and the second conductive plate 53 defines a corrugated surface, and the corrugated surface is formed with a plurality of first corrugations extending along a first axis of the conductive plates 52, 53, and a plurality of second corrugations extending along a perpendicular second axis of the conductive plates 52, 53. The first conductive plates 52 and the second conductive plates 53 are arranged to form a battery cell of the liquid flow battery 1, in which the corrugated surfaces of each of the first conductive plate 52 and the second conductive plate 53 provide a cathode and a corresponding anode of the battery cell, and define opposite walls of an electrolyte flow channel between the first conductive plate 52 and the second conductive plate 53.

[0081] The first conductive plate 52 and the second conductive plate 53 may be arranged so that the peaks (e.g., at least most of the peaks, optionally all of the peaks) of the corrugated surface of the first conductive plate 52 are accommodated within or aligned with the valleys of the corrugated surface of the second conductive plate 53 of the corresponding battery cell 11-16. The first conductive plate 52 and the second conductive plate 53 may be arranged so that the valleys (e.g., at least most of the valleys, optionally all of the valleys) of the first conductive plate 52 are accommodated within the peaks of the second conductive plate 53 of the corresponding battery cell 11-16.

[0082] Each of the battery cells 12-15 is formed by a pair of bipolar plates 50. In other words, the first conductive plate and / or the second conductive plate can be a bipolar plate 50. Each bipolar plate 50 includes a cathode surface 52 and an anode surface 53. The cathode surface of each battery cell 12-15 is provided by the first bipolar plate 50, and the anode surface 53 is provided by the second bipolar plate 50 spaced apart from the first bipolar plate 50. This arrangement of bipolar plates is Figure 3 is most clearly shown in Figure 3 Two battery cells 13 and 14 of the battery 1 are shown separately. The two battery cells 13 and 14 are formed by three bipolar plates 50.

[0083] Each bipolar plate 50 includes a conductive polymer core 51. The conductive polymer core 51 can be formed of a conductive composite material. The conductive composite material may include a polymer and conductive filler particles that are roughly uniformly distributed throughout the polymer. The polymer may include one or more of acrylonitrile butadiene styrene (ABS), polysulfone (PSU), polyethersulfone (PESU), or polyphenylene sulfide (PPS). The conductive filler particles may include one or more of carbon fibers, carbon nanotubes, graphene, carbon, fullerenes, or any other carbonaceous material, semiconductor, or metallic substance. The conductive filler particles may include materials coated with metals, metal alloys, semiconductor minerals, or oxides. The conductive filler particles may include metal fibers or powders. The conductive filler particles may contain gold, nickel, copper, lead, tin, iron, cobalt, magnesium, zinc, titanium, silver, aluminum, or alloys of one or more of these metals. The conductive filler particles have a diameter of up to 50 μm, for example, a diameter typically between 7 μm and 10 μm. The conductive composite material may include conductive filler particles that may be between 2% and 50% by volume but typically between 20% and 30%. In some embodiments, the anode surface or cathode surface, i.e., the first conductive plate and the second conductive plate, may include one or more of Fe, Mg, Ca, Zn, Al, Na, Ni in pure form or in alloy form. Alternatively, the anode surface 52 or cathode surface 53 may be provided by a non-metallic material, which may include one or more of C, Si or any other suitable anode or cathode material.

[0084] In this embodiment, the conductive polymer core can be formed from injection molded acrylonitrile butadiene styrene (ABS) containing about 20% by volume of uniformly dispersed zinc particles. The conductive zinc coating is disposed on opposite sides of the conductive polymer core 51 to provide a cathode surface 52 on one side of the bipolar plate 50 and an anode surface 53 on the opposite side of the bipolar plate 50. In other embodiments, the conductive polymer core can be formed from other suitable conductive polymer structures, and other conductive coatings can be used to provide the anode surface and the cathode surface.

[0085] In each battery cell 11-16, a separator 54 in the form of a Nafion flat sheet is provided between the cathode surface 52 and the anode surface 53. The space between the separator 54 and the cathode surface 52 is filled with a catholyte 56, and the space between the separator 54 and the anode surface 53 is filled with an anolyte 57. The electrolyte for the catholyte and the anolyte is a bipolar zinc-polyiodide. In other embodiments, other suitable electrolytes can of course be used.

[0086] The battery 1 is constructed so that the cathode electrolyte 56 and the anode electrolyte 57 are connected from top to bottom (along the Figure 1 and Figure 3 The orientation of the battery cells is shown in Figure 3 ) flows through the battery cell. Thus, the cathode electrolyte flow channel is defined between the separator 54 and the cathode surface 52, and the anode electrolyte flow channel is defined between the separator 54 and the anode surface 53. The battery cells 12-15 having adjacent battery cells on either side are each arranged in this manner. However, the battery cell 11 and the battery cell 16 having adjacent battery cells on only one side are formed by one bipolar plate and one unipolar plate. In particular, the battery cell 16 includes a cathode surface 52 provided by a bipolar plate shared with the adjacent battery cell 15 and an anode surface provided by a unipolar plate. The battery cell 11 includes an anode surface 53 provided by a bipolar plate shared with the adjacent battery cell 12 and a cathode surface provided by a unipolar plate. The unipolar plate can be arranged similarly to the bipolar plate 50, but with a conductive coating only on one side to provide a cathode or anode as required.

[0087] Each of the bipolar plates 50 includes a conductive polymer core 51 formed from a plate having corrugations extending along the length axis y of the plate and along the width axis x of the plate. So constructed, the conductive polymer core 51 includes a plurality of peaks and valleys arranged in an xy plane. This arrangement can result in the conductive polymer core 51 being generally egg-box shaped. The x-axis and y-axis defining the nominal plane of the conductive polymer core 51 are Figure 4 is marked, and Figure 4 The z-axis, which is perpendicular to the xy plane, is labeled in . The corrugations increase the area of ​​the cathode surface 52 and the anode surface 53, thereby increasing the power density of the cell 1 relative to a similar cell having planar cathode and anode surfaces.

[0088] Figure 5 A cross-sectional view in the yz plane of one of the bipolar plates 50 is shown. It can be seen that the corrugations provide the conductive polymer core 51 with a plurality of peaks 501 and valleys 502 which are spaced along the y-axis of the plate, which is the axis along which the electrolyte flows in use. Figure 6A cross-sectional view of the same bipolar plate 50 taken in the xz plane is shown in . It can be seen that the corrugations also provide the conductive polymer core 51 with a plurality of peaks 501 and valleys 502 which are spaced apart along the x-axis of the plate, which is an axis transverse to the axis along which the electrolyte flows in use. Figure 5 and Figure 6 As shown, the distance A between the peak 501 and the adjacent valley 502 along the y-axis of the plate is greater than the distance B between the peak 501 and the adjacent valley 502 along the x-axis of the plate, which means that there are more peaks 501 and valleys 502 per unit width W of the conductive polymer core 51 than there are peaks 501 and valleys 502 per unit length L of the conductive polymer core 51. In this case, the height V measured along the z-axis between the peaks 501 and valleys 502 is constant everywhere, so that the magnitude of the maximum slope of the conductive polymer core 51 along the width is greater than the magnitude of the maximum slope of the conductive polymer core 51 along the length of the conductive polymer core 51. In other words, the corrugation of the conductive polymer core 51 is steeper along the x-axis than along the y-axis.

[0089] While providing the cathode surface 52 and the anode surface 53 with corrugations increases the surface area of ​​these respective surfaces, thereby increasing the power density of the battery, the corrugations increase the tortuosity of the electrolyte flow path between the surfaces. Having corrugations that are too closely spaced along the electrolyte flow path, or having a plate that has too steep a slope along the flow path, can overly restrict fluid flow, which can adversely affect the performance of the flow battery. However, over most of the cathode surface 52 and the anode surface 53, there is no substantial electrolyte flowing along the x-axis. Therefore, the bipolar plates of the battery are arranged to have increased cathode and anode surface areas by providing a higher density of corrugations along the x-axis than along the y-axis, wherein the x-axis is oriented approximately perpendicular to the axis of general flow of the electrolyte and the y-axis is oriented approximately parallel to the axis of flow of the electrolyte. While the conductive polymer core 51 of each bipolar plate described herein includes a corrugated egg-box-type truncated pyramid structure, other embodiments may include other types of corrugations in the xy plane to increase the surface area of ​​the plate. Reference 9A to 9D , these may include hemispherical shapes 701 , conical shapes 702 , frustoconical shapes 703 , pyramidal shapes 704 or any other suitable shape.

[0090] Figure 7 A cell 313 of a bipolar battery according to a second embodiment is shown. The cell 313 has many of the same features as the cell 13 of the battery according to the first embodiment, so where the cell 313 has features as described with respect to the cell 13, these features have been labeled with the same reference numerals but prefixed with the numeral "3".

[0091] The battery cell 313 is formed of a bipolar plate 350 and is filled with a cathode electrolyte 356 and an anolyte 357. The difference between the battery cell 313 and the battery cell 13 of the battery according to the first embodiment is that the separator 60 of the battery cell 313 has been heat pressed to form a plurality of corrugations that are complementary to the shape of the corrugations formed in the conductive polymer core 351 of the bipolar plate. The separator 60 has a generally uniform thickness so that the positions of the peaks 61, 63 on one side of the separator 60 correspond to the positions of the valleys 62, 64 on the opposite side of the membrane. The separator 60 is held in its corrugated shape by a polymer grid 70 on which the separator 60 is placed, as shown in FIG. Figure 8 As shown. The grid 70 serves as a support structure that holds the separator 60 in place at a fixed distance from the cathode surface 352 and the anode surface 353 to achieve effective ion exchange. The grid structure is composed of acrylonitrile butadiene styrene, but in other embodiments, it can be composed of other non-conductive materials that remain inert in the chemical environment of the liquid flow battery cell.

[0092] The corrugations of the separator 60 are aligned with the corrugations of the conductive polymer core 351 so that peaks 61 formed by the separator 60 on the cathode side of the separator 60 are accommodated in valleys 3502 formed by the cathode surface 352, and so that peaks 3503 formed by the cathode surface 352 are accommodated in valleys 64 formed by the separator 60. Peaks 63 formed by the separator 60 on the anode side of the separator 60 are accommodated in valleys 3504 formed by the anode surface 353, and peaks 3505 formed by the anode surface 353 are accommodated in valleys 62 formed by the separator 60. The corrugated membrane 60 configured in this manner enables the cathode surface 352 and the anode surface 353 to be closer together than in an arrangement with a planar separator 54. Therefore, the corrugated separator 60 enables the size of the battery to be reduced relative to an arrangement with a planar separator.

[0093] In some embodiments, the plates may be provided with corrugations arranged to direct electrolyte between the cell inlet 800 and the cell outlet 801 via more than one electrolyte flow channel, or, alternatively or additionally, via (multiple) electrolyte flow channels that change direction in the xy plane between the cell inlet 800 and the cell outlet 801, such that the electrolyte flows along a non-linear path in the xy plane between the cell inlet 800 and the cell outlet 801. Such an arrangement may be advantageous in controlling the fluid flow rate through the cell so that the ions are exposed to the cathode and anode surfaces for a longer period of time, thereby optimizing the energy extracted from the electrolyte and ensuring that the electrolyte is sufficiently depleted when it reaches the cell outlet 801.

[0094] In some embodiments, the corrugations of the bipolar plates and the separators (optionally) between the plates can be shaped to restrict the net fluid flow between the cell inlet 800 and the cell outlet 801 to the spiral flow channel 805 in the xy plane (e.g., Fig. 10A ), or limited to the serpentine flow channel 806 (as shown Fig. 10B In embodiments including a diaphragm, the diaphragm may have a corrugation shape that is complementary to the corrugation shape of the bipolar plates, and the membrane may be positioned equidistantly between the bipolar plates. In other embodiments, the corrugations of the bipolar plates and the diaphragm (optionally) between the plates may be designed to flow along a plurality of flow channels 807 (e.g., Fig. 10C Parallel Murray patterns as shown, or Fig. 10D The parallel pattern shown) directs fluid from the battery cell inlet to the battery cell outlet.

[0095] In the foregoing description, if reference is made to integers or elements that have known, obvious or foreseeable equivalents, such equivalents are incorporated herein as if individually set forth. It should also be understood that integers or features described as preferred, advantageous, convenient, etc. are optional and do not constitute limitations on the scope of the claims. Furthermore, while these optional integers or features may be beneficial in certain embodiments, they may not be required in other embodiments and therefore may not be present.

Claims

1. A flow battery comprising: a first conductive plate; and The second conductive plate, wherein each of the first conductive plate and the second conductive plate comprises a corrugated surface formed with a plurality of first corrugations extending along a first axis of the conductive plate and a plurality of second corrugations extending along a perpendicular second axis of the conductive plate; Wherein, the first conductive plate and the second conductive plate are arranged to form a first battery cell of the liquid flow battery, in which the corrugated surfaces of each of the first conductive plate and the second conductive plate respectively provide a cathode and a corresponding anode of the first battery cell and define relative walls of an electrolyte flow channel between the first conductive plate and the second conductive plate.

2. The flow battery according to claim 1, wherein: The corrugated surface of at least one of the first conductive plate and the second conductive plate comprises: a plurality of first peaks and valleys extending along the first axis of the conductive plate; and a plurality of second peaks and valleys extending along the second axis of the conductive plate, The distance between a peak in the plurality of first peaks and valleys and an adjacent valley is different from the distance between a peak in the plurality of second peaks and valleys and an adjacent valley, for example, the difference is at least 20%.

3. The flow battery according to claim 2, wherein: The first conductive plate and the second conductive plate are arranged so that the first axes of each of the first conductive plate and the second conductive plate are oriented to be substantially parallel to the flow axis along which the electrolyte flows through the electrolyte flow channel, and wherein the distance between a peak of the plurality of first peaks and valleys and an adjacent valley along the first axis is greater than the distance between a peak of the plurality of second peaks and valleys and an adjacent valley along the second axis.

4. A flow battery according to any preceding claim, wherein: The corrugated surface of at least one of the first conductive plate and the second conductive plate comprises: a plurality of first peaks and valleys extending along the first axis of the conductive plate; and a plurality of second peaks and valleys extending along the second axis of the conductive plate, The maximum slope of the corrugated surface between peaks and valleys in the first plurality of peaks and valleys is different from the maximum slope of the corrugated surface between peaks and valleys in the second plurality of peaks and valleys.

5. The flow battery according to claim 4, wherein: The first conductive plate and the second conductive plate are arranged so that the first axes of each of the first conductive plate and the second conductive plate are oriented to be substantially parallel to the flow axis along which the electrolyte flows through the electrolyte flow channel, and wherein the magnitude of the maximum slope of the corrugated surface between peaks and valleys of the plurality of first peaks and valleys is smaller than the magnitude of the maximum slope of the corrugated surface between peaks and valleys of the plurality of second peaks and valleys.

6. A flow battery according to any one of the preceding claims, wherein: At least one of the first conductive plate and the second conductive plate is a corrugated plate having corrugated surfaces on opposite sides thereof.

7. The flow battery according to claim 6, wherein: The liquid flow battery includes a third conductive plate, wherein the second conductive plate and the third conductive plate are arranged to form a second battery cell of the liquid flow battery, in which the corrugated surfaces of each of the second conductive plate and the third conductive plate provide a cathode and a corresponding anode of the second battery cell and define relative walls of an electrolyte flow channel between the second conductive plate and the third conductive plate, and the second conductive plate thus forms an anode of one of the first battery cell and the second battery cell and a cathode of the other of the first battery cell and the second battery cell.

8. The flow battery according to claim 6 or 7, wherein: The second electrically conductive plate is a bipolar plate comprising a conductive polymer core including a corrugated anode surface and a corrugated cathode surface on opposing surfaces of the conductive polymer core.

9. The flow battery according to claim 8, wherein: The conductive polymer core includes a conductive composite material including a polymer and conductive filler particles that are substantially uniformly distributed throughout the polymer.

10. A flow battery according to any preceding claim, wherein: The liquid flow battery defines a cathode liquid flow channel adjacent to the cathode surface, an anode liquid flow channel adjacent to the anode surface, and one or more pumps, wherein the one or more pumps are used to pump cathode liquid along the cathode liquid flow channel in a first flow direction and pump anode liquid along the anode liquid flow channel in a second flow direction, wherein the first flow direction is substantially parallel to but in opposite directions from the second flow direction.

11. A flow battery according to any preceding claim, wherein: The flow battery includes a membrane between the first and second conductive plates such that the battery is configured with a cathode liquid flow path between the cathode surface and the membrane on a first side of the membrane and an anode liquid flow path between the anode surface and the membrane on an opposite second side of the membrane.

12. The flow battery according to claim 11, wherein: The diaphragm is formed with a plurality of first corrugations extending along a first axis of the diaphragm, and a plurality of second corrugations extending along a perpendicular second axis of the diaphragm.

13. The flow battery according to claim 12, wherein: The corrugations formed in the diaphragm are complementary in shape to the corrugated surface of at least one of the first conductive plate and the second conductive plate; and The diaphragms are arranged such that: The peaks of the corrugated surface of the diaphragm are received in the valleys of the corrugated surface of at least one of the first conductive plate and the second conductive plate; or The peaks of the corrugated surface of at least one of the first and second conductive plates are received in the valleys of the corrugated surface of the diaphragm.

14. The liquid flow battery according to claim 12 or 13, wherein: The diaphragm is supported by a grid structure.

15. The flow battery of claim 14, wherein: The grid structure is formed with a plurality of corrugations that are complementary to the shape of the corrugations formed in the diaphragm; and The surface of the diaphragm is supported on the grid structure such that the peaks of the grid structure are received in the valleys on the surface of the diaphragm and vice versa.

16. A flow battery according to any preceding claim, wherein: The first battery unit comprises: a battery cell inlet through which electrolyte is provided to the battery cell; and a battery cell outlet through which electrolyte exits the battery cell; and the corrugated surfaces of the first and second conductive plates are configured such that the electrolyte flow path changes direction in the xy plane between the battery cell inlet and the battery cell outlet.

17. A flow battery according to any preceding claim, wherein: The first battery unit comprises: a battery cell inlet through which electrolyte is provided to the battery cell; and a battery cell outlet through which electrolyte exits the battery cell; and the corrugated surfaces of the first and second conductive plates are configured such that two or more electrolyte flow paths are provided between the battery cell inlet and the battery cell outlet.

18. A conductive plate for a flow battery, the conductive plate being formed of a conductive composite material, the conductive composite material comprising: polymer; and conductive filler particles, the conductive filler particles being substantially uniformly distributed throughout the polymer, wherein the conductive composite material forms the conductive polymer core of the conductive plate, and The conductive plate comprises a corrugated surface, wherein the corrugated surface is formed with a plurality of first corrugations extending along a first axis of the conductive plate, and a plurality of second corrugations extending along a perpendicular second axis of the conductive plate.

19. The conductive plate according to claim 18, wherein: The polymer includes one or more of acrylonitrile butadiene styrene (ABS), polysulfone (PSU), polyethersulfone (PESU), or polyphenylene sulfide (PPS).

20. The conductive plate according to claim 18 or 19, wherein: The conductive plate includes between 2% and 50% by volume of conductive filler particles, such as between 20% and 30% by volume of conductive filler particles.

21. The conductive plate according to any one of claims 18 to 20, wherein: The electrically conductive filler particles have a diameter of at most 50 μm, for example typically between 7 μm and 10 μm.

22. The conductive plate according to any one of claims 18 to 21, wherein: The conductive polymer core includes opposing surfaces, and a conductive coating disposed on one or both of the opposing surfaces to form an anode surface and / or a cathode surface of the conductive plate.

23. A vehicle comprising a flow battery according to any one of claims 1 to 17, for example, wherein: The vehicle is a road vehicle, optionally an electric vehicle or a hybrid vehicle.

24. The vehicle of claim 22, wherein: One or more flow batteries according to any one of claims 1 to 17 are configured to provide electrical energy for driving a vehicle or to assist in driving a vehicle, optionally wherein the main power source for the vehicle is one or more flow batteries according to any one of claims 1 to 17.

25. A method of refueling a vehicle, the vehicle being a vehicle according to claim 23 or 24, wherein: The method comprises: extracting depleted electrolyte from the vehicle using a pump at the charging station; and The vehicle is supplied with charged electrolyte using a pump at the charging station.

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