Flow battery bipolar plate and current collecting plate

Abstract

The present disclosure provides a flow battery bipolar plate and current collecting plate. The bipolar plate or the current collecting plate comprises a supporting layer, and the supporting layer comprises a first surface in contact with an electrode and a second surface opposite thereto; the supporting layer is provided with holes penetrating through the first surface and the second surface; a conductive filler is disposed in the holes; the first surface is provided with a first area and a second area, the first area surrounding all the holes, and the second area being the remaining area of the first surface; the second surface is provided with a third area and a fourth area, the third area surrounding all the holes, and the fourth area being the remaining area of the second surface; and the resistivity of the first area is less than that of the second area. The present disclosure optimizes the bipolar plate or the current collecting plate while ensuring the physical strength thereof, thereby greatly improving the corrosion resistance, electrical properties and mechanical properties thereof.

Description

A liquid flow battery bipolar plate and current collecting plate Technical Field

[0001] This article relates to but is not limited to the field of liquid flow battery technology, and in particular to but is not limited to a bipolar plate and current collecting plate of an all-vanadium liquid flow battery. Background Art

[0002] Today, as new clean energy sources gradually replace traditional energy sources, energy storage systems, as an essential component of these systems, play a supporting role in the entire new power generation industry. Because new clean power generation energies (such as wind and solar energy) are significantly affected by natural environmental factors and struggle to continuously output stable and safe electricity, utilizing energy storage batteries as a link between these new power generation energies is crucial. In the energy storage battery sector, flow batteries are widely used in the energy storage industry due to their robust stability and safety, as well as their power capacity, durability, and long-term discharge capabilities, which far surpass other energy storage devices (such as lithium batteries, pumped hydro, and compressed air storage).

[0003] Currently, the bipolar plates or current collectors used in flow batteries are conductive plates made primarily of various resin plastics with conductive agents and dispersants as auxiliary materials. Resin plastics include PVDF, PP, PE, PVC, etc. Bipolar plates or current collectors made primarily of PVDF have good chemical corrosion resistance, high temperature resistance, oxidation resistance, and electrical conductivity, but their tensile strength and ductility are average. Edge seals are prone to bending or even breaking. Furthermore, due to the requirements of the working environment of the bipolar plates or current collectors, the areas not covered by the electrodes will corrode when exposed to the corresponding electrolyte, which can easily lead to internal leakage in the battery, affecting its normal use.

[0004] Summary of the Invention

[0005] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0006] The present invention uses metal plates or other plates with relatively high strength as the main supporting layer, punches holes in the electrode reaction area, fills the holes with conductive slurry, and forms a dense conductive film in the area after solidification using electrochemical deposition, physical vapor deposition, chemical vapor deposition and other methods, while coating the surface of the non-electrode reaction area with insulating slurry. The present invention has carried out weight reduction optimization on the basis of ensuring the physical strength of the bipolar plate. Conductive and insulating treatments are performed on the electrode area and the non-electrode area respectively. The tolerance and conductivity of the bipolar plate are greatly improved. If only single-sided preparation is performed, a stack current collector can be obtained, which can be in direct contact with the electrode. The use of bipolar plates in the stack is reduced and the conductivity is improved.

[0007] In an embodiment of the present disclosure, a support layer of a bipolar plate or a current collecting plate is provided, wherein the support layer includes a first surface in contact with an electrode and a second surface opposite thereto;

[0008] The support layer is provided with holes penetrating the first surface and the second surface;

[0009] A conductive filler is provided in the hole;

[0010] The first surface is provided with a first area and a second area, the first area surrounds all the holes, and the second area is the remaining area of ​​the first surface; the second surface is provided with a third area and a fourth area, the third area surrounds all the holes, and the fourth area is the remaining area of ​​the second surface;

[0011] The resistivity of the first region is lower than the resistivity of the second region.

[0012] In some embodiments provided by the present disclosure, the number of the holes may be one or more.

[0013] In some embodiments provided by the present disclosure, the area of ​​all the holes accounts for 10% to 70% of the area of ​​the first region;

[0014] In some embodiments provided by the present disclosure, the area of ​​all the holes accounts for 10% to 70% of the area of ​​the third region.

[0015] In some embodiments provided by the present disclosure, the density of the conductive filler is lower than the density of the material of the support layer;

[0016] In some embodiments provided by the present disclosure, the resistivity of the conductive filler is 1 mΩ×cm to 10 mΩ×cm.

[0017] In some embodiments provided by the present disclosure, the Brinell hardness of the support layer ranges from 20 HB to 500 HB.

[0018] In some embodiments provided by the present disclosure, the material of the support layer is selected from any one or more of stainless steel, copper alloy, titanium alloy, aluminum alloy and magnesium alloy.

[0019] In yet another aspect, an embodiment of the present disclosure provides a bipolar plate, the bipolar plate comprising the above-mentioned support layer;

[0020] The resistivity of the third region is less than the resistivity of the fourth region;

[0021] The first region and the third region are provided with a conductive coating, and the second region and the fourth region are provided with an insulating coating.

[0022] In some embodiments provided by the present disclosure, the thickness ratio of the conductive coating layer to the support layer is (1 to 10): (10 to 100);

[0023] In some embodiments provided by the present disclosure, the thickness ratio of the insulating coating layer to the supporting layer is (1 to 10): (10 to 100);

[0024] In some embodiments provided by the present disclosure, the resistivity of the conductive coating is 1 mΩ×cm to 10 mΩ×cm;

[0025] In some embodiments provided by the present disclosure, the resistivity of the insulating coating is greater than 1000 mΩ×cm;

[0026] In some embodiments provided in the present disclosure, the conductive coating is made of a doped C / CrN multilayer gradient coating, wherein the doping elements are selected from any one or more of Ti, Al, Mo, W, Nb, Ni, Zr, Fe and Si.

[0027] In some embodiments provided by the present disclosure, the type and ratio of each doping element are controlled by the selection of the doping target material and the current size.

[0028] In some embodiments provided by the present disclosure, the conductive coating can be prepared using any one or more of electrochemical deposition, physical vapor deposition, chemical vapor deposition, and magnetron sputtering.

[0029] In another aspect, an embodiment of the present disclosure provides a current collecting plate, the current collecting plate comprising the above-mentioned support layer;

[0030] The first region is provided with a conductive coating, and the second region is provided with an insulating coating.

[0031] In some embodiments provided by the present disclosure, the thickness ratio of the conductive coating layer to the support layer is (1 to 10): (10 to 100);

[0032] In some embodiments provided by the present disclosure, the thickness ratio of the insulating coating layer to the supporting layer is (1 to 10): (10 to 100);

[0033] In some embodiments provided by the present disclosure, the resistivity of the conductive coating is 1 mΩ×cm to 10 mΩ×cm;

[0034] In some embodiments provided by the present disclosure, the resistivity of the insulating coating is greater than 1000 mΩ×cm;

[0035] In some embodiments provided in the present disclosure, the conductive coating is made of a doped C / CrN multilayer gradient coating, wherein the doping elements are selected from any one or more of Ti, Al, Mo, W, Nb, Ni, Zr, Fe and Si.

[0036] In some embodiments provided by the present disclosure, the type and ratio of each doping element are controlled by the selection of the doping target material and the current size.

[0037] In some embodiments provided by the present disclosure, the conductive coating can be prepared using any one or more of electrochemical deposition, physical vapor deposition, chemical vapor deposition, and magnetron sputtering.

[0038] In another aspect, an embodiment of the present disclosure provides a flow battery, the flow battery comprising the bipolar plate described above;

[0039] And / or, the flow battery includes the above-mentioned current collecting plate;

[0040] The flow battery is selected from any one or more of an all-vanadium flow battery, an iron-chromium flow battery, a zinc-iron flow battery and a zinc-bromine flow battery.

[0041] In some embodiments provided by the present disclosure, the electrode is an electrode of a battery on one side of a bipolar plate in a liquid flow battery, and the second electrode is an electrode of a battery on the other side of the bipolar plate in the liquid flow battery.

[0042] The present invention uses metal plates or other plates with relatively high strength as the main supporting layer, punches holes in the electrode reaction area, fills the holes with conductive slurry, and forms a dense conductive film in the area after solidification using methods such as electrochemical deposition, physical vapor deposition, and chemical vapor deposition, while coating the surface of the non-electrode reaction area with insulating slurry. The present invention has carried out weight reduction optimization on the basis of ensuring the physical strength of the bipolar plate. Conductive and insulating treatments are performed on the electrode area and the non-electrode area respectively. The corrosion resistance, electrical properties and mechanical properties of the bipolar plate are greatly improved. If only single-sided preparation is performed, a stack current collector can be obtained, which can be in direct contact with the electrode. The use of stack bipolar plates is reduced and the conductivity is improved.

[0043] Other features and advantages of the present disclosure will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present disclosure. Other advantages of the present disclosure can be invented and achieved through the solutions described in the description. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The accompanying drawings are used to provide an understanding of the technical solution of the present disclosure and constitute a part of the specification. Together with the embodiments of the present disclosure, they are used to explain the technical solution of the present disclosure and do not constitute a limitation to the technical solution of the present disclosure.

[0045] FIG1 is a schematic diagram of a bipolar plate according to an embodiment of the present disclosure.

[0046] FIG2 is a cross-sectional view of a bipolar plate according to an embodiment of the present disclosure, wherein the cross section is perpendicular to the surface in contact with the electrodes.

[0047] FIG3 is a schematic diagram of a current collecting plate according to an embodiment of the present disclosure.

[0048] FIG4 is a cross-sectional view of a bipolar plate according to an embodiment of the present disclosure, wherein the cross section is perpendicular to the surface in contact with the electrodes.

[0049] FIG5A is a physical picture of the bipolar plate before cycling of Example 1 of the present disclosure.

[0050] FIG5B is a physical picture of the bipolar plate after 1000 cycles of Example 1 of the present disclosure.

[0051] Figure numerals: 1. Support layer; 2. Hole; 3. Conductive coating of the first region; 4. Insulating coating of the first region; 5. Conductive coating of the second region; 6. Insulating coating of the second region. DETAILED DESCRIPTION

[0052] To make the purpose, technical solutions and advantages of the present disclosure more clear, the embodiments of the present disclosure are described in detail below. It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present disclosure can be combined with each other in any manner.

[0053] In an embodiment of the present disclosure, a support layer of a bipolar plate or a current collecting plate is exemplarily provided, wherein the support layer includes a first surface in contact with an electrode and a second surface opposite thereto;

[0054] The support layer is provided with holes penetrating the first surface and the second surface;

[0055] A conductive filler is provided in the hole;

[0056] The first surface is provided with a first area and a second area, the first area surrounds all the holes, and the second area is the remaining area of ​​the first surface; the second surface is provided with a third area and a fourth area, the third area surrounds all the holes, and the fourth area is the remaining area of ​​the second surface;

[0057] The resistivity of the first region is lower than the resistivity of the second region.

[0058] For example, the number of the holes may be one or more.

[0059] Exemplarily, the area of ​​all the holes accounts for 10% to 70% of the area of ​​the first region;

[0060] Illustratively, the area of ​​all the holes accounts for 10% to 70% of the area of ​​the third region.

[0061] Exemplarily, the density of the conductive filler is lower than the density of the material of the support layer;

[0062] Exemplarily, the resistivity of the conductive filler is 1 mΩ×cm to 10 mΩ×cm.

[0063] Exemplarily, the Brinell hardness of the support layer ranges from 20 HB to 500 HB.

[0064] Exemplarily, the material of the support layer is selected from any one or more of stainless steel, copper alloy, titanium alloy, aluminum alloy and magnesium alloy. Exemplarily, the material of the support layer can be, for example, Tongrun Copper Aluminum T2 copper plate.

[0065] In another aspect, an embodiment of the present disclosure exemplarily provides a bipolar plate, the bipolar plate comprising the above-mentioned support layer;

[0066] The resistivity of the third region is less than the resistivity of the fourth region;

[0067] The first region and the third region are provided with a conductive coating, and the second region and the fourth region are provided with an insulating coating.

[0068] Exemplarily, the thickness ratio of the conductive coating layer to the support layer is (1 to 10): (10 to 100);

[0069] Exemplarily, the thickness ratio of the insulating coating layer to the supporting layer is (1 to 10):(10 to 100);

[0070] Exemplarily, the resistivity of the conductive coating is 1 mΩ×cm to 10 mΩ×cm;

[0071] Exemplarily, the resistivity of the insulating coating is greater than 1000 mΩ×cm;

[0072] Exemplarily, the conductive coating is made of a doped C / CrN multilayer gradient coating, wherein the doping elements are selected from any one or more of Ti, Al, Mo, W, Nb, Ni, Zr, Fe and Si.

[0073] Exemplarily, the type and ratio of each doping element are controlled by the selection of the doping target material and the magnitude of the current.

[0074] For example, the conductive coating may be prepared using any one or more of electrochemical deposition, physical vapor deposition, chemical vapor deposition, and magnetron sputtering.

[0075] In another aspect, an embodiment of the present disclosure exemplarily provides a current collecting plate, the current collecting plate comprising the above-mentioned support layer;

[0076] The first region is provided with a conductive coating, and the second region is provided with an insulating coating.

[0077] Exemplarily, the thickness ratio of the conductive coating layer to the support layer is (1 to 10): (10 to 100);

[0078] Exemplarily, the thickness ratio of the insulating coating layer to the supporting layer is (1 to 10):(10 to 100);

[0079] Exemplarily, the resistivity of the conductive coating is 1 mΩ×cm to 10 mΩ×cm;

[0080] Exemplarily, the resistivity of the insulating coating is greater than 1000 mΩ×cm;

[0081] Exemplarily, the conductive coating is made of a doped C / CrN multilayer gradient coating, wherein the doping elements are selected from any one or more of Ti, Al, Mo, W, Nb, Ni, Zr, Fe and Si.

[0082] Exemplarily, the type and ratio of each doping element are controlled by the selection of the doping target material and the magnitude of the current.

[0083] For example, the conductive coating may be prepared using any one or more of electrochemical deposition, physical vapor deposition, chemical vapor deposition, and magnetron sputtering.

[0084] In another aspect, an embodiment of the present disclosure exemplarily provides a flow battery, the flow battery comprising the bipolar plate described above;

[0085] And / or, the flow battery includes the above-mentioned current collecting plate;

[0086] The flow battery is selected from any one or more of an all-vanadium flow battery, an iron-chromium flow battery, a zinc-iron flow battery and a zinc-bromine flow battery.

[0087] Illustratively, the electrode is an electrode of a battery on one side of a bipolar plate in a liquid flow battery, and the second electrode is an electrode of a battery on the other side of a bipolar plate in the liquid flow battery.

[0088] Illustratively, the present disclosure provides a method for preparing the above-mentioned bipolar plate or current collecting plate, comprising:

[0089] 1) Support layer processing: Use a processing machine tool to drill holes in the support layer, and then polish it to obtain the base.

[0090] 2) The support layer is placed in a mold, conductive slurry is added into the mold, the plate is removed after vacuum drying, the solidified layer attached to the metal surface is scraped off and polished to obtain a substrate 1.

[0091] 3) Apply the insulating coating to the second and fourth regions of the substrate 1 and then vacuum dry. Coating thickness:

[0092] 4) Depositing a conductive coating on the first region and the third region to produce a bipolar plate.

[0093] For example, if the insulating coating is applied only to the second region in step 3) and the conductive coating is deposited only to the first region in step 4), a current collector can be obtained. Alternatively, the bipolar plate can be used as a current collector.

[0094] For example, the diameter of the holes may be 0.1 cm to 5 cm, the spacing between the holes may be 0.1 cm to 1 cm, and the thickness of the support plate may be 0.1 cm to 1 cm.

[0095] Exemplarily, the preparation of the conductive coating may include: mixing the main material, solvent, and dispersant in a ratio of 1:5:0.1 to form slurry A, and mixing the conductive agent, solvent, and dispersant in a ratio of 1:5:0.1 to form slurry B. Dry-mixing the main material and the conductive agent to obtain powder A. Mixing slurry A, slurry B, and powder A to form a conductive slurry.

[0096] The main ingredients can be polymer resin powders or emulsions, such as polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), and SBR. Solvents can include water, ethanol, tetrahydrofuran, or N-methylpyrrolidone (NMP). Dispersants can include polymer dispersants such as starch, methylcellulose, ethylcellulose, hydroxycellulose, and polyvinyl alcohol. Conductive agents can include carbon black materials such as acetylene black, Ketjen Black, superconductive carbon black, conductive carbon black SP, Ketjen Black ECP, carbon black pearls, carbon nanotubes, and graphene. Graphite materials can include fine flake graphite, flake graphite, expanded graphite, microcrystalline graphite, ultrafine carbon fibers, spherical graphite, and mesophase carbon microbeads. Metal powders can include metals with good conductivity, such as gold, silver, copper, and chromium-zinc. This is only one method for preparing the conductive slurry; any method for preparing bipolar plate slurry can be used.

[0097] For example, the insulating coating may be prepared by grinding or ball-milling the main material and the dispersant, and then adding the solvent and stirring evenly.

[0098] For example, the insulating paste is applied to the second region and then vacuum dried, with a coating thickness of 0.1 mm to 1 mm.

[0099] Illustratively, the thickness of the conductive coating may be 0.1 mm to 1 mm.

[0100] For example, embodiment 1 of the present disclosure is as follows:

[0101] Support layer processing: Pure 304 stainless steel (Brinell hardness of 187HB) was cut into specifications of 25cm×19cm×1cm, and the surface and edges were ground and polished. A 21cm×16cm rectangular area was drawn in the center of the front and back sides of the steel plate as the electrode area (i.e., the first area and the third area). A punch was used to drill holes in the electrode area with a hole diameter of 1cm and a hole spacing of 1cm. The area of ​​all holes accounted for 18% of the first (third) area, and the hole walls were ground and polished.

[0102] Conductive paste preparation: Polyvinylidene fluoride (PVDF), carboxymethyl cellulose (CMC), and N-methylpyrrolidone (NMP) were mixed and stirred in a weight ratio of 1.2:0.1:10 at a speed of 600 r / min for 5 hours. Conductive carbon black (SP), carboxymethyl cellulose (CMC), and N-methylpyrrolidone (NMP) were mixed and stirred in a weight ratio of 1:0.1:10 at a speed of 600 r / min for 5 hours. Polyvinylidene fluoride (PVDF) and conductive carbon black (SP) were ground in a weight ratio of 0.7:0.1 for 30 minutes. The three mixtures were mixed and stirred again at 600 r / min for 30 minutes. Vacuum degassing was then performed, and the speed was reduced to 200 r / min for 30 minutes. After returning to normal pressure, the speed was increased to 300 r / min for 3 hours to obtain the conductive paste. The resulting conductive paste had a density lower than that of the steel plate and a resistivity of 5 mΩ×cm.

[0103] Conductive slurry filling: Secure the steel plate in the mold and inject the conductive slurry into the mold. Place the mold in a vacuum drying oven and dry it at 120°C for 12 hours. Remove the mold from the mold using a scraper to remove excess material from the surface of the steel plate. Then, level, grind, and polish it again.

[0104] Preparation of the insulating slurry: Polyvinylidene fluoride (PVDF) and carboxymethyl cellulose (CMC) were mixed in a 9:1 ratio, ground for 30 minutes, and dry-blended in a mixer for 30 minutes. NMP was added to the mixing tank at a weight ratio of 9:1:50. The mixture was stirred at a speed of 600 rpm for 30 minutes. Vacuum degassing was then performed, and the speed was reduced to 200 rpm for 30 minutes. The mixture was then returned to normal pressure and the speed was increased to 300 rpm for 3 hours. This resulted in the insulating slurry. The resistivity of the insulating coating was 2560 mΩ×cm.

[0105] Surface layer growth and coating: The insulating slurry was applied to the non-electrode area (i.e., the second and fourth areas) with a coating thickness of 1 mm and vacuum dried for 6 hours. After ultrasonic cleaning, the film was placed in a UDP650 closed-field unbalanced magnetron sputtering ion plating device and vacuumed to a background vacuum of less than 5×10-6 Torr. Argon was then introduced to maintain a vacuum of 2×10 -2 Torr; adjust the substrate bias to -70V, the chromium target current to 7A, and deposit the Cr layer for 15 minutes. Control the bias at -60V, maintain the chromium target current at 7A, introduce nitrogen gas, and the ventilation rate is 25SCCM. Deposit the CrN coating for 30 minutes. Turn on the graphite target, gradually increase the graphite target current from 0A to 6A, control the bias at -60V, the chromium target current to 7A, and deposit the chromium carbon nitrogen layer for 15 minutes. Control the bias at -60V, the graphite target current to 6A, and deposit the graphite-like carbon coating for 0.5 hours. Finally, a conductive film-doped C / CrN multilayer coating is obtained. The resistivity of the conductive film is 2mΩ×cm, and the thickness of the conductive film is 0.1mm.

[0106] As can be seen from FIG. 5A and FIG. 5B , after the bipolar plate prepared in Example 1 was cycled 1000 times, the bipolar plate structure was stable without obvious deformation or weaving.

[0107] For example, embodiment 2 of the present disclosure is as follows:

[0108] Support layer processing: The plate material is T4 copper plate (Brinell hardness 40HB), the hole diameter is changed to 2 cm, and the other parameters are the same as in Example 1. The area of ​​the hole accounts for 32% of the first (third) area;

[0109] Conductive slurry preparation: Carboxymethyl cellulose (CMC), carbon black (KB), and copper powder were mixed and ground in a ratio of 0.5:1:1 for 30 minutes. SBR and water were then mixed in a weight ratio of 1:10 and stirred for 1 hour at 600 rpm. The CMC and KB mixture was then placed in a tank and stirred for 1 hour at 600 rpm. Vacuum degassing was then performed, and the speed was reduced to 200 rpm for 30 minutes. After returning to normal pressure, the speed was increased to 300 rpm for 2 hours to obtain the conductive slurry. The resulting conductive slurry had a density lower than that of the steel plate and a resistivity of 2.5 mΩ×cm.

[0110] Conductive paste filling: the same as in Example 1.

[0111] Preparation of insulating slurry: CMC and SBR were mixed in a weight ratio of 0.1:1 and stirred for 30 minutes at 600 rpm. Vacuum was then applied to remove bubbles, and the speed was reduced to 200 rpm for 30 minutes. The pressure was then restored to normal, and the speed was increased to 300 rpm for 3 hours. This produced an insulating slurry. The resistivity of the insulating coating was 1892 mΩ×cm. The thickness of the insulating coating was 1 mm.

[0112] Surface Layer Growth and Coating: While maintaining all other parameters consistent with Example 1, the Ti and Al targets were activated for elemental doping and microstructure control. The target currents for both the Ti and Al targets were maintained at 2 A and gradually decreased to 0 during the fifth step. A C / CrN multilayer coating doped with Ti and Al was produced. The conductive film had a resistivity of 1.6 mΩ×cm and a thickness of 1.5 mm.

[0113] Comparative Example 1:

[0114] The only difference between this comparative example and Example 1 is that it does not involve punching holes in the support body and placing conductive materials in the holes, and the other processes are exactly the same.

[0115] Comparative Example 2:

[0116] The only difference between this comparative example and Example 1 is that the support body is not perforated and the conductive coating is not deposited in the first and third regions, while the insulating coating is still provided in the second and fourth regions.

[0117] Comparative Example 3

[0118] The bipolar plate used in this comparative example is a common resin carbon bipolar plate without holes, purchased from Liaoning Kejing New Materials Co., Ltd., with a specification model of KVFP0101 D50.

[0119] The electrodes prepared in the embodiment and comparative example were applied to an all-vanadium liquid flow battery, and two liquid flow batteries were connected in series to form a small battery stack, which was then tested.

[0120] Table 1: Performance statistics of examples and comparative examples

[0121] The bipolar plates (or current collecting plates) prepared by the technical solution disclosed in the present invention not only reduce the weight, but also further improve the electrical performance and operational stability of the battery stack.

Claims

1. A support layer for a bipolar plate or a current collecting plate, characterized in that: The support layer includes a first surface in contact with the electrode and a second surface opposite thereto; The support layer is provided with holes penetrating the first surface and the second surface; A conductive filler is arranged in the hole; The first surface is provided with a first area and a second area, the first area surrounds all the holes, and the second area is the remaining area of ​​the first surface; the second surface is provided with a third area and a fourth area, the third area surrounds all the holes, and the fourth area is the remaining area of ​​the second surface; The resistivity of the first region is lower than the resistivity of the second region.

2. The support layer of the bipolar plate or the current collector according to claim 1, characterized in that: The area of ​​all the holes accounts for 10% to 70% of the area of ​​the first region; The area of ​​all the holes accounts for 10% to 70% of the area of ​​the third region.

3. The support layer of the bipolar plate or current collector according to claim 1 or 2, characterized in that: The density of the conductive filler is lower than the density of the material of the support layer; The resistivity of the conductive filler is 1 mΩ×cm to 10 mΩ×cm.

4. The support layer of the bipolar plate or current collector according to claim 1 or 2, characterized in that: The Brinell hardness of the support layer ranges from 20HB to 500HB.

5. The support layer of the bipolar plate or current collector according to claim 1 or 2, characterized in that: The material of the support layer is selected from any one or more of stainless steel, copper alloy, titanium alloy, aluminum alloy and magnesium alloy.

6. A bipolar plate, characterized in that: The bipolar plate comprises a support layer as claimed in any one of claims 1 to 5; The resistivity of the third region is less than the resistivity of the fourth region; The first region and the third region are provided with a conductive coating, and the second region and the fourth region are provided with an insulating coating.

7. The bipolar plate according to claim 6, characterized in that: The thickness ratio of the conductive coating layer to the support layer is (1 to 10): (10 to 100); The thickness ratio of the insulating coating layer to the supporting layer is (1 to 10): (10 to 100); The resistivity of the conductive coating is 1 mΩ×cm to 10 mΩ×cm; The resistivity of the insulating coating is greater than 1000 mΩ×cm; The conductive coating is made of a doped C / CrN multilayer gradient coating, wherein the doping elements are selected from any one or more of Ti, Al, Mo, W, Nb, Ni, Zr, Fe and Si.

8. A current collecting plate, characterized in that: The current collecting plate comprises a supporting layer as claimed in any one of claims 1 to 5; The first region is provided with a conductive coating, and the second region is provided with an insulating coating.

9. The current collecting plate according to claim 8, characterized in that: The thickness ratio of the conductive coating layer to the support layer is (1 to 10): (10 to 100); The thickness ratio of the insulating coating layer to the supporting layer is (1 to 10): (10 to 100); The resistivity of the conductive coating is 1 mΩ×cm to 10 mΩ×cm; The resistivity of the insulating coating is greater than 1000 mΩ×cm; The conductive coating is made of a doped C / CrN multilayer gradient coating, wherein the doping elements are selected from any one or more of Ti, Al, Mo, W, Nb, Ni, Zr, Fe and Si.

10. A liquid flow battery, characterized in that: The flow battery comprises the bipolar plate according to claim 6 or 7; And / or, the liquid flow battery comprises the current collecting plate according to claim 8 or 9; the liquid flow battery is selected from any one or more of an all-vanadium liquid flow battery, an iron-chromium liquid flow battery, a zinc-iron liquid flow battery and a zinc-bromine liquid flow battery.

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