A pipeline system for fluid energy storage

Abstract

This utility model discloses a pipeline system for flow hydride energy storage, including a battery stack assembly, a positive electrode storage tank assembly, a negative electrode storage tank assembly, a positive electrode main inlet pipeline assembly, a negative electrode main inlet pipeline assembly, a positive electrode branch pipeline assembly, a negative electrode branch pipeline assembly, a positive electrode manifold pipeline assembly, and a negative electrode manifold pipeline assembly. The layout and equipment of the pipeline system solve or alleviate some technical problems in flow hydride energy storage systems, including: uneven electrolyte flow rates in each battery causing significant current differences between battery stacks, leading to unstable system pipelines and voltage; leakage current generated by series connection of battery stacks, which greatly reduces the current efficiency of the energy storage system during operation; precipitation or stratification of the electrolyte during long-term low-temperature storage, which significantly affects the lifespan of the circulation pump and battery stack; and migration of the positive and negative electrolytes during long-term system operation, causing differences in liquid levels between the positive and negative electrode storage tanks. The design uses an ultrasonic level gauge, but condensation at the detection port during long-term operation reduces detection accuracy.

Description

Technical Field

[0001] This utility model relates to the field of fluid energy storage, specifically a fluid energy storage pipeline system. Background Technology

[0002] Flow hydride energy storage (HLS) has a very broad market prospect due to its advantages such as long cycle life, high safety, small capacity decay, and high energy efficiency. Currently, different types of HLS electrolytes are available on the market, including vanadium-based, zinc-bromine, iron-chromium, and zinc-iron. Although the basic principles are similar, the functions and layouts of the piping systems differ. The piping system design of HLS in related technologies mainly suffers from the following problems: First, uneven flow of electrolyte into each stack results in significant differences in charging and discharging currents, leading to instability in the system's pipeline flow velocity and the voltage of each stack. Second, leakage current generated by the stack components greatly reduces the current efficiency of the energy storage system during operation. Third, zinc-iron electrolytes are prone to precipitation or stratification when stored at low temperatures for extended periods, significantly impacting the lifespan of the circulating pump and stacks. Fourth, during long-term operation, migration of the positive and negative electrolytes causes differences in liquid levels between the positive and negative storage tanks. In related designs using ultrasonic level gauges, condensation at the detection port can reduce detection accuracy over long-term operation. Utility Model Content

[0003] This invention addresses the shortcomings and defects of existing technologies by proposing a fluid flow energy storage pipeline system, comprising: a fuel cell stack assembly, a liquid storage tank assembly, a main inlet pipeline assembly, a main return pipeline assembly, and a heat exchange pipeline assembly. It solves problems such as uneven fuel cell flow, fuel cell leakage, electrolyte deposition, and migration monitoring, thereby improving the lifespan of the energy storage system, increasing energy efficiency, and reducing degradation.

[0004] The objective of this utility model can be achieved through the following technical solutions:

[0005] A fluid flow energy storage pipeline system includes a fuel cell stack assembly, a liquid storage tank assembly, a main inlet pipeline assembly, a main return pipeline assembly, and a heat exchange pipeline assembly.

[0006] The fuel cell stack assembly includes multiple fuel cells, and each fuel cell stack has a ball valve at its inlet and outlet.

[0007] The liquid storage tank assembly includes: a positive electrode liquid storage tank, a negative electrode liquid storage tank, an exhaust pipe, and a pressure detection pipe. The positive electrode liquid storage tank is used to store the positive electrode electrolyte, and the negative electrode liquid storage tank is used to store the negative electrode electrolyte. The exhaust pipe connects the top of the positive electrode liquid storage tank and the negative electrode liquid storage tank to discharge the gas inside the tank. There are two pressure detection pipes, which are installed in the middle of the negative electrode liquid storage tank and the positive electrode liquid storage tank, respectively.

[0008] The main inlet pipeline assembly includes a positive electrode main inlet pipeline assembly and a negative electrode main pipeline assembly. One end of the positive electrode main pipeline assembly is connected to the positive electrode storage tank, and the other end of the positive electrode main pipeline assembly is provided with a positive electrode shunt pipeline assembly connected to the fuel cell stack assembly. One end of the negative electrode main pipeline assembly is connected to the negative electrode storage tank, and the other end of the negative electrode main pipeline assembly is provided with a negative electrode shunt pipeline assembly connected to the fuel cell stack assembly.

[0009] The main return pipeline assembly includes a positive electrode return pipeline assembly and a negative electrode return pipeline assembly. One end of the positive electrode return pipeline assembly is equipped with a positive electrode manifold assembly connected to the fuel cell stack assembly by a ball valve, and the other end of the positive electrode return pipeline assembly is connected to the positive electrode storage tank. One end of the negative electrode return pipeline assembly is equipped with a negative electrode manifold assembly connected to the fuel cell stack assembly by a ball valve, and the other end of the negative electrode return pipeline assembly is connected to the negative electrode storage tank.

[0010] The heat exchange pipeline assembly includes a temperature control device, a positive electrode heat exchange pipeline and a negative electrode heat exchange pipeline. The positive electrode heat exchange pipeline is connected to the heat exchanger in the positive electrode liquid inlet main pipeline, and the negative electrode heat exchange pipeline is connected to the heat exchanger in the negative electrode liquid inlet main pipeline.

[0011] The exhaust pipe includes two branches that are respectively connected to the top of the positive electrode storage tank and the negative electrode storage tank. The two branches converge at the main exhaust valve to discharge the gas inside the tank.

[0012] The bottom ends of the two pressure detection pipelines are connected to pressure sensors, which are used to detect the liquid level and pressure in the positive electrode storage tank and the negative electrode storage tank, respectively.

[0013] The positive electrode inlet main pipeline assembly includes a positive electrode sampling valve, a positive electrode filter, a positive electrode circulation pump, a positive electrode electromagnetic flow meter, and a positive electrode exhaust valve; the negative electrode inlet main pipeline assembly includes a negative electrode sampling valve, a negative electrode filter, a negative electrode circulation pump, a negative electrode electromagnetic flow meter, and a negative electrode exhaust valve.

[0014] The positive electrode return main pipeline assembly includes a negative electrode check valve at the end near the positive electrode storage tank to prevent backflow of electrolyte in the positive electrode pipeline of the fuel cell stack. The negative electrode return main pipeline assembly also includes a negative electrode check valve at the end near the negative electrode storage tank to prevent backflow of electrolyte in the negative electrode pipeline of the fuel cell stack.

[0015] The positive electrode shunt pipe assembly, positive electrode busbar assembly, negative electrode shunt pipe assembly, and negative electrode busbar assembly each consist of a main pipe and the same number of branches as the fuel cell stack, with each branch having the same length.

[0016] The electric three-way valve includes a positive electric three-way valve installed between the positive electrode inlet main pipeline assembly and the positive electrode return main pipeline assembly, and a negative electric three-way valve installed between the negative electrode inlet main pipeline assembly and the negative electrode return main pipeline assembly; the inlet of the positive electric three-way valve is located after the positive electrode circulation pump, and the two outlets of the positive electric three-way valve are respectively located on the pipeline between the inlet of the positive electrode electromagnetic flowmeter and the return port of the positive electrode storage tank; the inlet of the negative electric three-way valve is located after the negative electrode circulation pump, and the two outlets of the negative electric three-way valve are respectively located on the pipeline between the inlet of the negative electrode electromagnetic flowmeter, the outlet of the negative electrode check valve, and the return port of the negative electrode storage tank.

[0017] According to the liquid flow energy storage pipeline system of this utility model embodiment, the electrolyte in the positive or negative electrode storage tank will first pass through the heat exchanger and filter equipment in sequence. The temperature of the electrolyte is regulated by the heat exchanger to accelerate the dissolution of crystals in the electrolyte. At the same time, the filter is used to filter out the crystals that the electrolyte cannot dissolve, so as to prevent the crystals from entering the stack pipeline and damaging the circulation pump and the stack.

[0018] According to the liquid flow energy storage pipeline system of this utility model embodiment, the electrolyte in the positive electrode liquid inlet main pipeline assembly or the negative electrode liquid inlet main pipeline assembly will enter the diversion pipeline assembly or the storage tank through the switching of the electric three-way valve. When the electrolyte in the storage tank precipitates or separates due to long-term non-operation of the energy storage system, the electrolyte can be switched back to the storage tank directly through the electric three-way valve to achieve uniform stirring of the electrolyte in the storage tank before charging.

[0019] The liquid flow energy storage pipeline system provided by this utility model requires the electrolyte to flow into the distribution pipeline assembly before flowing into the fuel cell stack assembly, and to flow out of the manifold assembly before flowing out of the fuel cell stack assembly. The extension of the branch pipeline base pipe of the distribution pipeline assembly and the manifold assembly increases the resistance of the pipeline between the fuel cell stacks to reduce leakage current. The consistent length of the branch pipelines serves to evenly distribute the electrolyte in the main pipeline to the pipelines of each fuel cell stack.

[0020] The liquid flow energy storage pipeline system provided by this utility model includes pressure sensors connected to the bottom of both the positive and negative electrode liquid storage tanks and the liquid level display pipeline. These sensors are used to detect the liquid level signals in the positive and negative electrode liquid storage tanks, respectively, and to feed the liquid level signals back to the battery pipeline system of the energy storage unit so that the system can promptly remind maintenance personnel to replenish the two storage tanks with water.

[0021] Furthermore, each of the positive and negative electrode storage tanks is connected to an exhaust branch pipe at its top, which eventually converges at the main exhaust valve at the end. The gas discharged from the main exhaust valve enters the gas treatment device to prevent the gas concentration in the energy storage system environment from increasing and causing safety hazards.

[0022] Furthermore, both the positive electrode liquid inlet main pipeline assembly and the negative electrode liquid inlet main pipeline flow meter are equipped with exhaust valves to discharge air from the pipeline.

[0023] The foregoing has shown and described the basic principles, main features, and functions of this utility model. It effectively solves or alleviates some of the problems existing in current fluid flow energy storage technology mentioned in the background art. Based on this reason, this utility model can be widely promoted in the structural layout of fluid flow energy storage pipeline systems. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure of the liquid flow energy storage pipeline system according to an embodiment of the present utility model.

[0025] Figure 2 yes Figure 1 Schematic diagram of the positive electrode shunt pipe assembly and the negative electrode shunt pipe assembly.

[0026] Figure 3 yes Figure 1 Schematic diagram of the positive electrode manifold assembly and the negative electrode manifold assembly.

[0027] Figure label:

[0028] fuel cell stack assembly 1;

[0029] Positive electrode storage tank assembly 2; Positive electrode storage tank 21; Positive electrode level display pipe 22; Positive electrode pressure sensor 23; Positive electrode exhaust branch pipe 24;

[0030] Negative electrode liquid storage tank assembly 3; negative electrode liquid storage tank 31; negative electrode liquid level display pipe 32; negative electrode pressure sensor 33; negative electrode exhaust branch pipe 34;

[0031] Positive electrode liquid inlet main pipeline assembly 4; Positive electrode sampling valve 41; Positive electrode heat exchanger 42; Positive electrode filter 43; Positive electrode circulation pump 44; Positive electrode electric three-way valve 45; Positive electrode electromagnetic flow meter 46; Positive electrode exhaust valve 47;

[0032] 5. Negative electrode inlet main pipeline assembly; 51. Negative electrode sampling valve; 52. Negative electrode heat exchanger; 53. Negative electrode filter; 54. Negative electrode circulating pump; 55. Negative electrode electric three-way valve; 56. Negative electrode electromagnetic flow meter; 57. Negative electrode exhaust valve;

[0033] Positive electrode shunt pipe assembly 6;

[0034] Negative electrode shunt pipe assembly 7;

[0035] Positive electrode manifold assembly 8;

[0036] Negative busbar assembly 9;

[0037] Positive check valve 10;

[0038] Negative check valve 11;

[0039] Main exhaust valve 12;

[0040] Temperature control device 13;

[0041] Positive electrode temperature control circulation pipeline 14;

[0042] Negative electrode temperature control circulation pipeline 15;

[0043] Convergence Main Road 16;

[0044] 17. Combination branch pipe;

[0045] Diversion main pipeline 18;

[0046] Branch pipe 19; Detailed Implementation

[0047] To facilitate understanding of the basic principles, main features, and functions of this utility model, the following description, in conjunction with specific embodiments and accompanying drawings, further illustrates the utility model. However, the following embodiments are merely preferred embodiments of this utility model and not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments described herein without creative effort are all within the protection scope of this utility model.

[0048] like Figure 1 and Figure 2 As shown, the fluidized bed energy storage pipeline system according to an embodiment of this utility model includes a fuel cell stack assembly 1, a positive electrode storage tank assembly 2, a negative electrode storage tank assembly 3, a positive electrode main inlet pipeline assembly 4, a negative electrode main inlet pipeline assembly 5, a positive electrode branch pipeline assembly 6, a negative electrode branch pipeline assembly 7, a positive electrode manifold pipeline assembly 8, and a negative electrode manifold pipeline assembly 9. This embodiment is a zinc-iron fluidized bed energy storage type, but in other embodiments, energy storage types such as all-vanadium, zinc-bromine, and all-iron are still applicable.

[0049] The battery stack assembly 1 includes multiple battery stacks, each of which contains four ball valves 16 for controlling the on / off state or flow rate of the electrolyte in the pipelines of each battery stack.

[0050] The positive electrode storage tank assembly 2 includes a positive electrode storage tank 21, a positive electrode level display pipe 22, a positive electrode pressure sensor 23, and a positive electrode venting branch pipe 24. The positive electrode storage tank 21 is used to store the positive electrode electrolyte. The positive electrode level display pipe 22 is a U-shaped transparent tube structure used to display the liquid level height in the storage tank. The positive electrode pressure sensor 23 is installed at the bottom of the positive electrode level display pipe to obtain the liquid level signal in the positive electrode storage tank 21 and feed the liquid level signal back to the battery management system to promptly remind maintenance personnel to replenish the positive electrode storage tank 21 with water.

[0051] The negative electrode storage tank assembly 3 includes a negative electrode storage tank 31, a negative electrode level display pipe 32, a negative electrode pressure sensor 33, and a negative electrode exhaust branch pipe 34. The negative electrode storage tank 31 is used to store the negative electrode electrolyte, and its other features are the same as those of the positive electrode storage tank assembly in terms of structure and function.

[0052] The positive electrolyte enters the positive main pipeline assembly 4 from the positive electrolyte storage tank 21, see details. Figure 1 As shown, the positive electrode inlet main pipeline 4, in sequence according to the electrolyte flow direction, includes a positive electrode sampling valve 41, a positive electrode heat exchanger 42, a positive electrode filter 43, a positive electrode circulation pump 44, a positive electrode electric three-way valve 45, a positive electrode electromagnetic flowmeter 46, and a positive electrode exhaust valve 47. The positive electrode sampling valve is used for routine maintenance sampling to check for abnormalities in the electrolyte composition within the tank. The positive electrode heat exchanger 42 is connected to the temperature control device 13 via the positive electrode temperature control circulation pipeline 14, used for heat exchange with the electrolyte to prevent crystallization due to excessively low temperatures. The positive electrode filter 43 prevents particulate matter or crystals in the electrolyte from entering the pipeline, causing damage to the positive electrode circulation pump 44 and blockage of the battery stack. The positive electrode electric three-way valve 45 is powered by the battery. Controlled by the management system, the two outlets are respectively installed on the pipeline between the inlet of the positive electromagnetic flowmeter 46 and the return port of the positive storage tank 21. When the energy storage system has not been running for a long time, causing the electrolyte to precipitate or separate, the electric three-way valve can be switched to allow the electrolyte in the main pipeline to return directly to the positive storage tank 21, thereby agitating the electrolyte in the tank and dissolving crystals and precipitates. The positive electromagnetic flowmeter 46 can collect the flow data of the electrolyte in the main pipeline and increase or decrease the flow rate by adjusting the frequency of the positive circulation pump. During system operation, when there is a lot of gas in the pipeline, the gas will enter the highest point of the pipeline due to the filling of the electrolyte. The positive exhaust valve 47 is installed here to discharge the gas in the pipeline.

[0053] The composition and function of the negative electrode main pipeline assembly 5 are the same as those of the positive electrode main pipeline assembly 4. The negative electrode electric three-way valve 55 is controlled by the battery pipeline system. Its two outlets are respectively installed on the pipeline between the inlet of the negative electrode electromagnetic flowmeter 56 and the return port of the negative electrode storage tank 31. When the energy storage system is not running for a long time, the electric three-way valve can be switched to allow the negative electrode electrolyte in the negative electrode main pipeline to return directly to the negative electrode storage tank 31, thereby realizing the stirring of the electrolyte in the tank and dissolving crystals and precipitates.

[0054] The positive electrode shunt pipe assembly 6 and the negative electrode shunt pipe assembly 7 have the same structure and function, such as... Figure 2Taking the positive electrode shunt pipeline assembly 6 as an example, the shunt main pipeline 16 and the shunt branch pipelines 17 are distributed in a tree-like manner. In order to reduce the pressure loss of the shunt pipeline assembly, the cross-sectional area of ​​the main pipeline 16 is greater than 1.2 times the sum of the cross-sectional areas of the shunt branch pipelines 17. In addition, the shunt branch pipelines 17 are divided into two parts. One part increases the resistance of the pipeline between the fuel cells to reduce the leakage current, and the other part extends the pipeline to make the pressure loss of each shunt branch pipeline more consistent, so that the electrolyte is evenly distributed to each fuel cell.

[0055] The positive electrode busbar assembly 8 and the negative electrode busbar assembly 9 have the same structure as the positive electrode shunt assembly 6 described above, except for the direction of electrolyte flow. Figure 3 As shown.

[0056] To ensure that the electrolyte in the pipeline system does not flow back when the energy storage system stops operating or when the positive electrode liquid inlet main pipeline assembly 4 and the positive electrode liquid inlet main pipeline assembly 5 are operating their stirring functions, a positive electrode check valve 10 and a negative electrode check valve 11 are installed on the positive and negative electrode return main pipelines, respectively.

[0057] During the operation of the energy storage system, gas will be released from the electrolyte. In order to avoid the accumulation of gas in the system and the resulting safety hazards, the positive electrode exhaust branch pipe 24 and the negative electrode exhaust branch pipe 34 converge at the main exhaust valve 12 to discharge the gas outdoors or to a gas treatment device (not shown).

[0058] This invention effectively solves the adverse effects on the system caused by uneven flow rates of various energy storage stacks, high leakage losses of energy storage stacks, and electrolyte precipitation and migration, greatly improving the lifespan of the energy storage system, increasing energy efficiency, and reducing degradation.

[0059] The above embodiments are descriptions of specific implementations of this utility model, and not limitations thereof. Those skilled in the art can make various modifications and changes without departing from the spirit and scope of this utility model to obtain corresponding equivalent technical solutions. Therefore, all equivalent technical solutions should be included in the patent protection scope of this utility model.

Claims

1. A pipe system for liquid flow energy storage, characterized in that This includes fuel cell stack assembly, liquid storage tank assembly, main inlet pipeline assembly, main return pipeline assembly, heat exchange pipeline assembly, and electric three-way valve; The fuel cell stack assembly includes multiple fuel cells, and each fuel cell stack is equipped with a ball valve at both its inlet and outlet. The liquid storage tank assembly includes a positive electrode liquid storage tank, a negative electrode liquid storage tank, an exhaust pipe, and two pressure detection pipes. The positive electrode liquid storage tank is used to store positive electrode electrolyte, and the negative electrode liquid storage tank is used to store negative electrode electrolyte. The exhaust pipe connects the top of the positive electrode liquid storage tank and the negative electrode liquid storage tank to discharge the gas inside the tank. There are two pressure detection pipes, which are respectively installed in the middle part of the negative electrode liquid storage tank and the positive electrode liquid storage tank. The main inlet pipeline assembly includes a positive electrode main inlet pipeline assembly and a negative electrode main inlet pipeline assembly. One end of the positive electrode main inlet pipeline assembly is connected to the positive electrode storage tank, and the other end of the positive electrode main inlet pipeline assembly is provided with a positive electrode shunt pipeline assembly that is connected to the fuel cell stack assembly. One end of the negative electrode main inlet pipeline assembly is connected to the negative electrode storage tank, and the other end of the negative electrode main inlet pipeline assembly is provided with a negative electrode shunt pipeline assembly that is connected to the fuel cell stack assembly. The return liquid main pipeline assembly includes a positive electrode return liquid main pipeline assembly and a negative electrode return liquid main pipeline assembly. One end of the positive electrode return liquid main pipeline assembly is equipped with a positive electrode manifold assembly connected to the fuel cell stack assembly ball valve, and the other end of the positive electrode return liquid main pipeline assembly is connected to the positive electrode storage tank. One end of the negative electrode return liquid main pipeline assembly is equipped with a negative electrode manifold assembly connected to the fuel cell stack assembly ball valve, and the other end of the negative electrode return liquid main pipeline assembly is connected to the negative electrode storage tank. The heat exchange pipeline assembly includes a temperature control device, a positive electrode heat exchange pipeline and a negative electrode heat exchange pipeline. The positive electrode heat exchange pipeline is connected to the heat exchanger in the positive electrode liquid inlet main pipeline, and the negative electrode heat exchange pipeline is connected to the heat exchanger in the negative electrode liquid inlet main pipeline.

2. The liquid flow energy storage pipe system of claim 1, wherein, The exhaust pipe includes two branches that are respectively connected to the top of the positive electrode storage tank and the negative electrode storage tank. The two branches converge at the main exhaust valve to discharge the gas inside the tank.

3. The liquid flow energy storage pipe system of claim 1, wherein, The bottom ends of the two pressure detection pipelines are connected to pressure sensors, which are used to detect the liquid level and pressure in the positive electrode storage tank and the negative electrode storage tank, respectively.

4. The liquid flow energy storage pipe system of claim 1, wherein, The positive electrode inlet main pipeline assembly includes a positive electrode sampling valve, a positive electrode filter, a positive electrode circulation pump, a positive electrode electromagnetic flow meter, and a positive electrode exhaust valve; the negative electrode inlet main pipeline assembly includes a negative electrode sampling valve, a negative electrode filter, a negative electrode circulation pump, a negative electrode electromagnetic flow meter, and a negative electrode exhaust valve.

5. The liquid flow energy storage pipe system of claim 4, wherein, The positive electrode return main pipeline assembly includes a negative electrode check valve at the end near the positive electrode storage tank to prevent backflow of electrolyte in the positive electrode pipeline of the fuel cell stack. The negative electrode return main pipeline assembly also includes a negative electrode check valve at the end near the negative electrode storage tank to prevent backflow of electrolyte in the negative electrode pipeline of the fuel cell stack.

6. The liquid flow energy storage pipe system of claim 1, wherein, The positive electrode shunt pipe assembly, positive electrode busbar assembly, negative electrode shunt pipe assembly, and negative electrode busbar assembly each consist of a main pipe and the same number of branches as the fuel cell stack, with each branch having the same length.

7. The liquid flow energy storage pipe system of claim 5, wherein, The electric three-way valve includes a positive electric three-way valve installed between the positive electrode inlet main pipeline assembly and the positive electrode return main pipeline assembly, and a negative electric three-way valve installed between the negative electrode inlet main pipeline assembly and the negative electrode return main pipeline assembly; the inlet of the positive electric three-way valve is located after the positive electrode circulation pump, and the two outlets of the positive electric three-way valve are respectively located on the pipeline between the inlet of the positive electrode electromagnetic flowmeter and the return port of the positive electrode storage tank; the inlet of the negative electric three-way valve is located after the negative electrode circulation pump, and the two outlets of the negative electric three-way valve are respectively located on the pipeline between the inlet of the negative electrode electromagnetic flowmeter, the outlet of the negative electrode check valve, and the return port of the negative electrode storage tank.

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