Electrolyte uniform distribution device for liquid flow battery stack and liquid flow battery stack containing the same

Abstract

The present invention provides an electrolyte uniform distribution device for a flow battery stack and a flow battery stack including the same, wherein the electrolyte uniform distribution device includes a uniform distribution component, the uniform distribution component has a flow channel for electrolyte circulation, the flow channel is provided with at least two liquid separation holes for communicating with the opening of the flow frame limiting channel of a single group of flow batteries; along the flow direction of the electrolyte, the opening cross-sectional area of ​​the at least two liquid separation holes on the flow channel decreases, and / or, along the flow direction of the electrolyte, the cross-sectional area of ​​the flow channel for circulating the electrolyte decreases. Without changing the original stack manufacturing process, the present invention achieves the consistency of the liquid inlet amount of each group of flow batteries inside the stack through the uniform distribution component, improves the uniformity of the electrolyte flow distribution between each single battery, and increases the overall energy efficiency of the stack; and can effectively reduce the risk of leakage failure of the stack and increase the service life.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid flow batteries, and in particular to an electrolyte uniform distribution device for a liquid flow battery stack and a liquid flow battery stack comprising the same. Background Art

[0002] At present, the output of clean energy such as wind energy, solar energy, and tidal energy is extremely unstable and greatly affected by climate and weather. Combining unstable clean energy with energy storage technology, storing unstable electricity and releasing it stably to meet commercial and civilian requirements has become the key to solving the problem of unstable clean energy utilization. At the same time, energy storage technology can store excess electricity during low electricity consumption periods and release it during peak electricity consumption periods to maximize the utilization of electricity.

[0003] Liquid flow battery energy storage technology is a new type of electrochemical energy storage technology. It is a device that realizes the mutual conversion of electrical energy and chemical energy through the redox reaction of active substances in the electrolyte on the electrode. It is mainly used to support the joint energy storage of wind and solar power generation and the peak and valley power consumption allocation of the power grid. It is a large-scale energy storage device.

[0004] Liquid flow battery technology has the advantages of safety, reliability, high cost-effectiveness during the life cycle, environmental friendliness, and long cycle life. It has great potential in the field of large-scale long-term energy storage exceeding 4 hours. Among them, all-vanadium liquid flow batteries have the highest degree of industrialization and the largest number of projects under construction. Zinc-bromine liquid flow batteries, zinc-iron liquid flow batteries, iron-chromium liquid flow batteries, and aqueous organic liquid flow batteries all have projects built, and the future market is huge.

[0005] The fuel cell stack is the place where electrochemical reactions occur in the liquid flow battery and is the core component for energy storage and release. The performance of the fuel cell stack directly determines the output power, energy efficiency and service life of the liquid flow battery, and directly affects the operation of the entire liquid flow battery energy storage system. The stable operation of the fuel cell stack is the basis for ensuring the long-term stable operation of the liquid flow battery system.

[0006] Good thermal management, electrochemical balance, pressure control, etc. are all key factors that need to be considered in the design of the battery stack. The problem of battery stack leakage has become the key factor affecting the life of the battery stack. The uneven distribution of electrolyte is the main reason for the low energy efficiency of electric energy. To solve the problem of uneven electrolyte, the current method is to change the opening diameter of the single cell and the opening diameter of the flow limiting channel of the single cell liquid flow frame to achieve uniform distribution of electrolyte. This will result in different structural designs for each single cell, increasing the cost of industrial mass production of the battery stack. The leakage of electrolyte in the battery stack is mainly concentrated in the main flow channel area of ​​the electrolyte, and there is currently no good solution.

[0007] Therefore, it is necessary to develop a new structure for distributing the electrolyte to the battery stack to solve the problems of uneven electrolyte distribution and electrolyte leakage. Summary of the invention

[0008] In order to solve the above technical problems, the present invention provides an electrolyte uniform distribution device for a liquid flow battery stack and a liquid flow battery stack comprising the same. For the liquid flow battery stack, uniform distribution components with different electrolyte flow cross-sections are designed to achieve consistent liquid inlet amounts for each group of liquid flow batteries inside the stack, improve the uniformity of electrolyte flow distribution between each single liquid flow battery, and increase the overall energy efficiency of the stack; and the uniform distribution components of the present invention can effectively reduce the risk of leakage failure of the battery stack and increase its service life.

[0009] To achieve this object, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides an electrolyte evenly distributing device for a liquid flow battery stack, the electrolyte evenly distributing device comprising an evenly distributing component, the evenly distributing component having a liquid flow channel for circulating electrolyte, the liquid flow channel being provided with at least two liquid separation holes for communicating with the opening of a liquid flow frame limiting channel of a single group of liquid flow batteries; along the flow direction of the electrolyte, the opening cross-sectional areas of the at least two liquid separation holes on the liquid flow channel decrease, and / or, along the flow direction of the electrolyte, the cross-sectional area of ​​the liquid flow channel for circulating electrolyte decreases.

[0011] It is worth noting that the present invention is aimed at a flow battery stack rather than a single group of flow batteries or a single flow battery. In the process of distributing the electrolyte in the flow battery stack, due to the influence of the length of the liquid flow channel inside the flow battery stack, the pressure of the electrolyte reaching the liquid inlet of each single flow battery is different and the flow rate is different, resulting in a situation where the flow rate of the electrolyte flowing into each single flow battery is different. The present invention arranges a uniform distribution component, that is, arranges along the flow direction of the electrolyte, so that the opening cross-sectional area of ​​at least two liquid separation holes on the liquid flow channel decreases, and / or the cross-sectional area of ​​the liquid flow channel used to circulate the electrolyte decreases, so that the flow rate of the electrolyte at each location can be made equivalent, so as to achieve the effect of uniform distribution of the electrolyte.

[0012] Preferably, the uniform distribution component is used to be arranged in the electrolyte shared channel of the battery stack and is sealed and connected to the electrolyte shared channel.

[0013] The present invention can avoid leakage of electrolyte by sealingly connecting the uniformly distributed components with the electrolyte shared channel, thereby increasing the service life of the battery.

[0014] Preferably, the sealed connection method includes adhesive sealing and / or laser welding sealing.

[0015] Preferably, the exterior of the uniformly distributed component is a circular tube with a constant outer diameter, and the outer diameter of the uniformly distributed component is matched with the inner diameter of the electrolyte shared channel.

[0016] Generally speaking, the cross section of the electrolyte shared channel is circular, so the exterior of the uniformly distributed component of the present invention is configured as a circular tube with a uniform outer diameter, so that it can match the electrolyte shared channel.

[0017] Preferably, the liquid flow channel and the circular tube of equal outer diameter are eccentrically arranged, that is, the central axis of the liquid flow channel does not coincide with the central axis of the circular tube of equal outer diameter.

[0018] Preferably, the central axis of the liquid flow channel is arranged away from the liquid separation hole.

[0019] The present invention preferably uses an eccentrically arranged liquid flow channel and a circular tube of equal outer diameter to make the wall thickness of the uniformly distributed component near the liquid separation hole thicker, thereby achieving a better sealing effect when docking with the opening of the liquid flow frame flow limiting channel to prevent electrolyte leakage.

[0020] Preferably, both ends of the uniformly distributed component are sealed with end plates of the fuel cell stack.

[0021] Preferably, one end of the uniform distribution component is open, and the other end is provided with a sealing plate.

[0022] Preferably, the number of the liquid separation holes on the liquid flow channel is the same as the number of groups of liquid flow batteries in the liquid flow battery stack, and each liquid separation hole is connected to the opening of the liquid flow frame limiting channel of a single group of liquid flow batteries.

[0023] Preferably, each group of flow batteries includes at least one single flow battery.

[0024] Preferably, the central axes of the liquid separation holes on the liquid flow channel are on the same straight line, and the opening lengths of the liquid separation holes in the axial direction are the same.

[0025] Preferably, non-perforated sections are provided at both ends of the liquid flow channel, and the length of the non-perforated sections is greater than or equal to the thickness of the end plates on both sides of the liquid flow battery stack.

[0026] Preferably, the width of the interval between two adjacent liquid separation holes is less than or equal to the width of the flow limiting channel of the liquid flow frame between two adjacent groups of single-group liquid flow batteries.

[0027] Preferably, the width of the liquid separation hole in a direction perpendicular to the axial direction ranges from 1 to 10 mm, for example, it may be 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm or 10 mm.

[0028] Preferably, along the flow direction of the electrolyte, when the opening cross-sectional area of ​​at least two liquid separation holes on the liquid flow channel decreases, the difference in width between two adjacent liquid separation holes in the direction perpendicular to the axial direction is 0.01~2mm, for example, it can be 0.01mm, 0.24mm, 0.46mm, 0.68mm, 0.9mm, 1.12mm, 1.34mm, 1.56mm, 1.78mm or 2mm, etc.

[0029] The present invention further preferably has a width difference between two adjacent liquid separation holes in a direction perpendicular to the axial direction within the above range, which can better improve the distribution uniformity of the electrolyte.

[0030] Preferably, along the flow direction of the electrolyte, when the cross-sectional area of ​​the liquid flow channel for circulating the electrolyte decreases, the axis of the liquid flow channel away from the side of the liquid separation hole is inclined toward the side of the liquid separation hole.

[0031] Preferably, the inclined tapered angle is 5-30°, for example, it can be 5°, 8°, 11°, 14°, 17°, 19°, 22°, 25°, 28° or 30°.

[0032] The present invention further preferably has the inclined tapered angle within the above range, which can better improve the distribution uniformity of the electrolyte.

[0033] Preferably, in a region where the axis of the liquid flow channel away from the liquid separation hole is inclined toward the liquid separation hole, there is a gap space between the outer side of the uniform distribution component and the liquid flow channel.

[0034] Preferably, the material of the uniformly distributed component includes any one of PP, PE, PVC, PPH, UPVC or CPVC, or a combination of at least two of them, wherein typical but non-limiting combinations are a combination of PP and PE, a combination of PVC and PE, a combination of PP and PVC, a combination of PPH and PE, a combination of UPVC and PE, and a combination of PP and CPVC.

[0035] Preferably, the single flow battery comprises an all-vanadium flow battery, an iron-chromium flow battery or an aqueous organic flow battery.

[0036] In a second aspect, the present invention provides a liquid flow battery stack, wherein the liquid flow battery stack comprises the electrolyte uniform distribution device of the liquid flow battery stack described in the first aspect.

[0037] The second aspect of the present invention provides a high uniformity of distribution between the liquid flow batteries inside the liquid flow battery stack, and the electrolyte in the liquid flow battery is not easy to leak, the battery life is longer, and the application prospects are broad.

[0038] Compared with the prior art, the present invention has at least the following beneficial effects:

[0039] (1) The electrolyte uniform distribution device for the flow battery stack provided by the present invention can realize the equal supply of electrolyte in the modules in the flow battery stack, improve the uniformity of electrolyte flow distribution between each single flow battery, and the range of the electrolyte flow rate at the electrolyte inlet of the single flow battery in the stack is within 2.5×10 -3 m / s, and improve the energy efficiency of the battery stack, which is above 83%;

[0040] (2) The electrolyte uniform distribution device of the flow battery stack provided by the present invention installs the uniform distribution component in the electrolyte shared channel of the stack and seals the connection, thereby reducing the risk of leakage failure of the stack and increasing the service life of the stack;

[0041] (3) The distribution component in the electrolyte distribution device of the flow battery stack provided by the present invention has a simple structure and is easy to apply in engineering. There is no need to change the original single cell hole opening process. In addition, the hole opening structure of each single cell is consistent, which is easy to mechanically process and can save processing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a semi-sectional schematic diagram of the electrolyte uniform distribution device provided in Example 1 of the present invention.

[0043] Figure 2 It is a schematic diagram of the overall view of the electrolyte uniform distribution device provided in Example 1 of the present invention.

[0044] Figure 3 It is a schematic diagram of the structure of the electrolyte uniform distribution device provided in Example 1 of the present invention installed in a liquid flow battery stack.

[0045] Figure 4 It is a schematic diagram of the cross-sectional structure inside the liquid flow battery stack provided in Example 1 of the present invention.

[0046] Figure 5 It is an enlarged schematic diagram of the structure in which the electrolyte uniform distribution device provided in Example 1 of the present invention is connected to the liquid flow battery stack.

[0047] Figure 6 This is a half-section schematic diagram of the electrolyte uniform distribution device provided in Example 3 of the present invention.

[0048] Figure 7 It is a schematic diagram of the overall view of the electrolyte uniform distribution device provided in Example 3 of the present invention.

[0049] Figure 8 This is a diagram of the simulation results of the liquid flow velocity after the electrolyte uniform distribution device of the liquid flow battery stack provided in Example 3 of the present invention is installed.

[0050] Fig. 9 This is a diagram of the simulation results of the liquid flow velocity after the electrolyte uniform distribution device of the liquid flow battery stack provided in Comparative Example 1 of the present invention is installed.

[0051] Among them: 1. Uniformly distributed components; 11. Liquid flow channel; 12. Liquid separation hole; 13. Spacer; 14. Liquid inlet end spacer; 15. Liquid outlet end spacer; 16. Tapered angle; 2. Liquid flow battery stack; 21. Electrolyte shared channel; 22. Electrode frame flow channel area; 23. Electrode reaction area; 24. Liquid flow frame flow limiting channel opening; 25. Electrode frame. DETAILED DESCRIPTION

[0052] For the convenience of understanding the present invention, the present invention lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0053] It should be understood that, in the description of the present invention, the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0054] It should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0055] Example 1

[0056] This embodiment provides an electrolyte uniform distribution device for a liquid flow battery stack, the electrolyte uniform distribution device comprising a uniform distribution component, the uniform distribution component having a liquid flow channel for electrolyte circulation, the liquid flow channel being provided with 6 liquid distribution holes for communicating with the opening of the liquid flow frame limiting channel of a single group of liquid flow batteries;

[0057] See also Figure 1~Figure 2 , along the flow direction of the electrolyte, the opening cross-sectional areas of at least two liquid separation holes on the liquid flow channel decrease gradually.

[0058] See also Figure 3~Figure 5, the uniformly distributed component is used to be arranged in the electrolyte shared channel of the battery stack and is sealed and connected with the electrolyte shared channel; the sealing connection method is adhesive sealing; the outside of the uniformly distributed component is a circular tube with equal outer diameter, and the outer diameter of the uniformly distributed component is matched with the inner diameter of the electrolyte shared channel; the liquid flow channel is eccentrically arranged with the circular tube with equal outer diameter, that is, the central axis of the liquid flow channel does not coincide with the central axis of the circular tube with equal outer diameter, and the central axis of the liquid flow channel is arranged away from the liquid separation hole. One end of the uniformly distributed component is open, and a sealing plate is arranged at the other end. The two ends of the uniformly distributed component are end-face sealed with the end plates of the battery stack.

[0059] The number of liquid separation holes on the liquid flow channel is the same as the number of groups of liquid flow batteries in the liquid flow battery stack, and each liquid separation hole is connected to the opening of the liquid flow frame limiting channel of a single group of liquid flow batteries; each group of liquid flow batteries includes 10 single liquid flow batteries, and the number of single liquid flow batteries in each group of liquid flow batteries is the same.

[0060] The central axes of the liquid separation holes on the liquid flow channel are on the same straight line, and the opening lengths of the liquid separation holes in the axial direction are the same; non-perforated sections are provided at both ends of the liquid flow channel, and the length of the non-perforated sections is ≥ the thickness of the end plates on both sides of the liquid flow battery stack.

[0061] The width of the interval between two adjacent liquid separation holes is ≤ the width of the liquid flow frame flow limiting channel between two adjacent groups of single liquid flow batteries. The width of the liquid separation hole in the direction perpendicular to the axial direction ranges from 1 to 6 mm (initial 6 mm, final 1 mm).

[0062] When the opening cross-sectional areas of the six liquid separation holes on the liquid flow channel decrease along the electrolyte flow direction, the difference in width between two adjacent liquid separation holes in the direction perpendicular to the axial direction is 1 mm.

[0063] The material of the uniformly distributed component is PP; the single flow battery includes an all-vanadium flow battery.

[0064] Example 2

[0065] The present embodiment provides an electrolyte evenly distributing device for a liquid flow battery stack, in which the liquid flow channel is provided with 10 liquid distribution holes for connecting with the opening of the liquid flow frame limiting channel of a single group of liquid flow batteries, and the sealing connection is carried out by laser welding. The widths of the liquid distribution holes in the direction perpendicular to the axial direction are 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm and 5.5mm respectively, and the material of the evenly distributing component is PVC; the single liquid flow battery is an aqueous organic liquid flow battery, and the rest is the same as Example 1.

[0066] Example 3

[0067] This embodiment provides an electrolyte uniform distribution device for a liquid flow battery stack, the electrolyte uniform distribution device comprising a uniform distribution component, the uniform distribution component having a liquid flow channel for electrolyte circulation, the liquid flow channel being provided with 5 liquid distribution holes for communicating with the opening of the liquid flow frame limiting channel of a single group of liquid flow batteries;

[0068] See also Figure 6~Figure 7 , along the flow direction of the electrolyte, the cross-sectional area of ​​the flow channel for circulating the electrolyte decreases.

[0069] The uniformly distributed component is used to be arranged in the electrolyte shared channel of the battery stack and is sealed and connected with the electrolyte shared channel; the sealing connection is in the form of adhesive sealing; the exterior of the uniformly distributed component is a circular tube of equal outer diameter, and the outer diameter of the uniformly distributed component is matched with the inner diameter of the electrolyte shared channel; the liquid flow channel is eccentrically arranged with the circular tube of equal outer diameter, that is, the central axis of the liquid flow channel does not coincide with the central axis of the circular tube of equal outer diameter, and the central axis of the liquid flow channel is arranged away from the liquid separation hole. One end of the uniformly distributed component is open, and the other end is provided with a sealing plate; the two ends of the uniformly distributed component are sealed with the end plates of the battery stack.

[0070] The number of liquid separation holes on the liquid flow channel is the same as the number of groups of liquid flow batteries in the liquid flow battery stack, and each liquid separation hole is connected to the opening of the liquid flow frame limiting channel of a single group of liquid flow batteries; each group of liquid flow batteries includes 10 single liquid flow batteries, and the number of single liquid flow batteries in each group of liquid flow batteries is the same.

[0071] The central axes of the liquid separation holes on the liquid flow channel are on the same straight line, and the opening lengths of the liquid separation holes in the axial direction are the same; non-perforated sections are provided at both ends of the liquid flow channel, and the length of the non-perforated sections is ≥ the thickness of the end plates on both sides of the liquid flow battery stack.

[0072] The width of the interval between two adjacent liquid separation holes is ≤ the width of the liquid flow frame flow limiting channel between two adjacent groups of single-group liquid flow batteries. The width of the liquid separation holes in the direction perpendicular to the axial direction is 5.5 mm.

[0073] When the cross-sectional area of ​​the liquid flow channel for circulating the electrolyte decreases along the flow direction of the electrolyte, the axis of the liquid flow channel away from the liquid separation hole is inclined toward the liquid separation hole; the tapering angle of the inclination is 15°. In the area where the axis of the liquid flow channel away from the liquid separation hole is inclined toward the liquid separation hole, there is a gap space between the outer side of the uniform distribution component and the liquid flow channel.

[0074] The material of the uniformly distributed component is PPH; the single flow battery includes an all-vanadium flow battery.

[0075] The COMSOL Multiphysics simulation software is used to simulate the liquid inlet flow rate of the flow battery in this embodiment, and the simulation results are shown in the figure below: Figure 8 As shown, from Figure 8 It can be seen that the flow rates of each liquid inlet are relatively close, and the surface electrolyte is evenly distributed.

[0076] Example 4

[0077] The present embodiment provides an electrolyte uniform distribution device for a liquid flow battery stack, in which the liquid flow channel is provided with 8 liquid distribution holes for connecting with the liquid flow frame limiting channel opening of a single group of liquid flow batteries, and the sealing connection is laser welding sealing. The width of the liquid distribution holes in the direction perpendicular to the axial direction is 10 mm, the inclined tapered angle is 5°, and the material of the uniform distribution component is UPVC; the single liquid flow battery is an iron-chromium liquid flow battery, and the rest is the same as Example 3.

[0078] Example 5

[0079] The present embodiment provides an electrolyte uniform distribution device for a liquid flow battery stack, in which the liquid flow channel is provided with 6 liquid distribution holes for connecting with the liquid flow frame limiting channel opening of a single group of liquid flow batteries, and the sealing connection is laser welding sealing. The width of the liquid distribution holes in the direction perpendicular to the axial direction is 4.0 mm, the inclined tapered angle is 30°, and the material of the uniform distribution component is CPVC; the single liquid flow battery is an aqueous organic liquid flow battery, and the rest is the same as Example 3.

[0080] The technical effect achieved by Example 2 is equivalent to that of Example 1; the technical effects achieved by Examples 4~5 and Example 3 are equivalent to that of Example 3.

[0081] Example 6

[0082] This embodiment provides an electrolyte uniform distribution device for a liquid flow battery stack. The electrolyte uniform distribution device is the same as that of Embodiment 3 except that the inclined tapered angle is 45°, and will not be described in detail here.

[0083] Example 7

[0084] This embodiment provides an electrolyte uniform distribution device for a liquid flow battery stack. The electrolyte uniform distribution device is the same as that of Embodiment 3 except that the inclined tapered angle is 2°, and will not be described in detail here.

[0085] Example 8

[0086] This embodiment provides an electrolyte uniform distribution device for a liquid flow battery stack. The electrolyte uniform distribution device is the same as that of Embodiment 1 except that the difference in width between two adjacent liquid separation holes in a direction perpendicular to the axial direction is 2.5 mm, and is not described in detail here.

[0087] Example 9

[0088] The present embodiment provides an electrolyte evenly distributing device for a liquid flow battery stack, which is the same as that of Embodiment 3 except that in the area where the axis of the liquid flow channel is inclined toward the liquid separation hole, and the outer side of the evenly distributing component and the liquid flow channel are provided with a dense material, and thus will not be described again.

[0089] Compared with Example 3, the energy density of the battery in this embodiment is reduced.

[0090] Example 10

[0091] The present embodiment provides an electrolyte evenly distributing device for a liquid flow battery stack. The electrolyte evenly distributing device is the same as Embodiment 1 except that non-perforated sections are provided at both ends of the liquid flow channel. However, the length of the non-perforated sections is less than the thickness of the end plates on both sides of the liquid flow battery stack. Such description will not be repeated here.

[0092] Embodiment 11

[0093] The present embodiment provides an electrolyte evenly distributing device for a liquid flow battery stack. The electrolyte evenly distributing device is the same as that of Embodiment 1 except that the interval between two adjacent liquid separation holes is greater than the width of the liquid flow frame limiting channel between two adjacent groups of single liquid flow batteries, and will not be described in detail here.

[0094] Comparative Example 1

[0095] This comparative example provides an electrolyte uniform distribution device for a liquid flow battery stack. The electrolyte uniform distribution device is the same as Example 1 except that the openings of the separation holes are the same, that is, the width of the separation holes in the direction perpendicular to the axial direction is 3 mm, and the rest is not repeated here.

[0096] The COMSOL Multiphysics simulation software is used to simulate the liquid inlet flow rate of the flow battery in this embodiment, and the simulation results are shown in the figure below: Fig. 9 As shown, from Fig. 9 It can be seen that the flow rates of various liquid inlets vary greatly, and the surface electrolyte distribution effect is poor.

[0097] When installing the electrolyte uniform distribution device of the flow battery stack provided by the present invention, the uniform distribution component is inserted into the electrolyte sharing channel of the stack and sealed, and the charging and discharging performance of the stack is tested to obtain the energy efficiency of the stack.

[0098] Taking the 60 groups of single flow batteries provided in Example 1, Example 3, Examples 6 to 11 and Comparative Example 1 as examples, the all-vanadium flow battery stack was tested and the energy efficiency of the stack was recorded.

[0099] The test results of the above embodiments and comparative examples are shown in Table 1.

[0100] Table 1

[0101]

[0102] From Table 1, we can see the following points:

[0103] (1) By comparing Example 3 with Examples 6-7, it can be seen that the large taper angle of the uniform distribution tube device in Example 6 leads to a large flow rate of electrolyte at the outlet of the uniform distribution tube device, and a poor electrolyte uniform distribution effect. The range of the electrolyte flow rate at the electrolyte inlet of the single flow battery in the battery stack reaches 3.86×10 -3 m / s, and the performance of the battery stack is reduced; in Example 7, the tapered angle of the uniformly distributed tube device is too small, resulting in a large flow rate of the electrolyte at the inlet end of the uniformly distributed tube device, and the electrolyte uniform distribution effect is poor, with a range of 4.47×10 -3 m / s, the energy efficiency of the stack is reduced to 81.35%, which shows that the present invention further improves the energy efficiency of the stack by optimizing the design of the tapered angle;

[0104] (2) By comparing Example 1 with Example 8, it can be seen that the difference in width between the two liquid separation holes of the uniform distribution tube device in Example 8 in the direction perpendicular to the axial direction is too large, resulting in a large difference in the flow rate of the electrolyte at the liquid separation holes at the inlet and outlet of the uniform distribution device. It is impossible to ensure that the flow rate of the electrolyte entering each single cell is consistent, and the effect of uniform distribution of the electrode liquid cannot be achieved. The extreme difference between the electrolyte flow rates at the electrolyte inlet of the single flow battery in the battery stack is as high as 4.86×10 -3 m / s, the energy efficiency of the battery stack is reduced to 81.30%, indicating that the present invention can better improve the uniform distribution effect of the electrolyte by controlling the difference in width between two adjacent liquid separation holes in the direction perpendicular to the axial direction within a reasonable range;

[0105] (3) By comparing Example 1 with Examples 10-11, it can be seen that the length of the non-perforated sections at both ends of the uniformly distributed tube in Example 10 is less than the thickness of the end plates on both sides of the flow battery stack, and there are dead zones for the electrolyte at both ends of the inlet and outlet of the uniformly distributed device, and there is a local eddy current phenomenon in the electrolyte, resulting in a decrease in the utilization rate of the electrolyte. In Example 11, the interval between the liquid distribution holes of the uniformly distributed tube is greater than the width of the liquid flow frame flow limiting channel between two adjacent groups of single flow batteries, and there is a phenomenon that the liquid inlet of a single flow battery is blocked by the interval between the liquid distribution holes of the uniformly distributed device, resulting in the electrolyte being unable to enter the flow battery, resulting in the low energy efficiency of the single battery in the flow battery stack that cannot participate in the reaction.

[0106] (4) By comparing Example 1 with Comparative Example 1, it can be seen that the present invention can realize equal supply of electrolyte to modules in a flow battery stack by setting and designing equalizing components with different electrolyte flow cross-sections, thereby improving the uniformity of electrolyte flow distribution between each single flow battery and improving the energy efficiency of the stack.

[0107] The present invention illustrates the detailed features of the present invention through the above embodiments, but the present invention is not limited to the above detailed features, that is, it does not mean that the present invention must rely on the above detailed features to be implemented. Those skilled in the art should understand that any improvement to the present invention, equivalent replacement of the technical features selected by the present invention, addition of auxiliary technical features, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. An electrolyte uniform distribution device for a flow battery stack, characterized in that: The electrolyte uniform distribution device comprises a uniform distribution component, the uniform distribution component has a liquid flow channel for the circulation of the electrolyte, and the liquid flow channel is provided with at least two liquid separation holes for communicating with the opening of the liquid flow frame limiting channel of the single group of liquid flow batteries; Along the flow direction of the electrolyte, the opening cross-sectional area of ​​at least two liquid separation holes on the liquid flow channel decreases, and / or, along the flow direction of the electrolyte, the cross-sectional area of ​​the liquid flow channel for circulating the electrolyte decreases; The uniformly distributed component is used to be arranged in the electrolyte shared channel of the battery stack and is sealed and connected to the electrolyte shared channel; Both ends of the liquid flow channel are provided with non-perforated sections, and the length of the non-perforated sections is greater than or equal to the thickness of the end plates on both sides of the liquid flow battery stack; The width of the interval between two adjacent liquid separation holes is less than or equal to the width of the flow limiting channel of the liquid flow frame between two adjacent groups of single-group liquid flow batteries; When the opening cross-sectional area of ​​at least two liquid separation holes on the liquid flow channel decreases along the flow direction of the electrolyte, the difference in width between two adjacent liquid separation holes in the direction perpendicular to the axial direction is 0.01~2mm; and / or, when the cross-sectional area of ​​the liquid flow channel for circulating the electrolyte decreases along the flow direction of the electrolyte, the axis of the liquid flow channel away from the side of the liquid separation hole is inclined toward the side of the liquid separation hole; the tapering angle of the inclination is 5~30°.

2. The electrolyte uniform distribution device according to claim 1, characterized in that: The exterior of the uniformly distributed component is a circular tube with a uniform outer diameter, and the outer diameter of the uniformly distributed component is matched with the inner diameter of the electrolyte shared channel; The liquid flow channel is eccentrically arranged with respect to the circular tube with the same outer diameter, and the central axis of the liquid flow channel is arranged away from the liquid separation hole.

3. The electrolyte uniform distribution device according to claim 1 or 2, characterized in that: The number of the liquid separation holes on the liquid flow channel is the same as the number of groups of liquid flow batteries in the liquid flow battery stack, and each liquid separation hole is connected to the opening of the liquid flow frame limiting channel of a single group of liquid flow batteries; Each group of flow batteries includes at least one single flow battery.

4. The electrolyte uniform distribution device according to claim 3, characterized in that: The central axes of the liquid separation holes on the liquid flow channel are on the same straight line, and the opening lengths of the liquid separation holes in the axial direction are the same.

5. The electrolyte uniform distribution device according to claim 1, characterized in that: The width of the liquid separation hole in a direction perpendicular to the axial direction ranges from 1 to 10 mm.

6. The electrolyte uniform distribution device according to claim 1, characterized in that: In a region where the axis of the liquid flow channel away from the liquid separation hole is inclined toward the liquid separation hole, there is a gap space between the outer side of the uniform distribution component and the liquid flow channel.

7. The electrolyte uniform distribution device according to claim 3, characterized in that: The material of the uniform distribution component includes any one of PP, PE, PVC, PPH, UPVC or CPVC, or a combination of at least two thereof; The single flow battery includes an all-vanadium flow battery, an iron-chromium flow battery or an aqueous organic flow battery.

8. A liquid flow battery stack, characterized in that: The liquid flow battery stack comprises the electrolyte uniform distribution device of the liquid flow battery stack according to any one of claims 1 to 7.

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