Liquid storage system with pressure regulating function and working method thereof

Abstract

The invention belongs to the technical field of flow batteries, and particularly relates to a liquid storage system with a pressure regulating function and a working method thereof. The liquid storage system comprises a liquid storage tank, and an air bag is arranged in the liquid storage tank; the opening of the air bag can be communicated with the outside, so that the volume of the air bag can change along with the pressure in the liquid storage tank, and the pressure in the liquid storage tank is always equal to the outside atmospheric pressure. The air bag is arranged in the liquid storage tank, and the volume of the air bag changes along with the pressure in the liquid storage tank, so that the pressure in the liquid storage tank is always equal to the external atmospheric pressure. When the pressure in the liquid storage tank changes, air enters and exits from the air bag and does not make contact with the electrolyte in the liquid storage tank. Therefore, the conditions that when the negative pressure in the liquid storage tank exceeds the suction opening pressure of the breather valve, the breather valve is opened, the air directly enters the liquid storage tank, the air makes contact with the electrolyte, and the electrolyte is oxidized can be effectively prevented. In addition, nitrogen does not need to be supplemented at any time in the using process, and the nitrogen cost is saved.

Description

Technical Field

[0001] The present invention belongs to the technical field of liquid flow batteries, and in particular relates to a liquid storage system with a pressure regulating function and a working method thereof. Background Art

[0002] The energy unit of the flow battery energy storage system, the electrolyte, is stored in a liquid storage tank made of insulating material. When designing the liquid storage tank, a certain amount of surplus is generally considered to prevent the electrolyte from overflowing due to the deviation of the electrolyte.

[0003] When the energy storage system is running, some gas will be released, which will form a positive pressure in the storage tank. When the pressure reaches a certain value, it will be discharged from the storage tank through the breathing valve.

[0004] In addition, the following situations may occur during the operation of the liquid flow battery energy storage system: (1) As part of the electrolyte enters the pipeline and the battery stack, the liquid level in the liquid storage tank will drop, forming a negative pressure in the liquid storage tank; (2) As the electrolyte continues to shift in the positive and negative electrode storage tanks, a negative pressure will also be formed in one of the liquid storage tanks; (3) Opening the balance valve in the positive and negative electrode storage tanks will cause the high liquid level in the storage tank to move to the low liquid level, which will also cause a negative pressure to form in one of the liquid storage tanks. All three situations may cause air to enter the liquid storage tank through the breathing valve, oxidize the electrolyte, and affect the quality of the electrolyte. In order to prevent air from entering the liquid storage tank and affecting the electrolyte, nitrogen is generally continuously added to the liquid storage tank to isolate the air, but nitrogen is relatively expensive. If it is continuously replenished, it will increase the energy storage cost.

[0005] In order to solve the above problems, the present invention is proposed. Summary of the invention

[0006] When the liquid flow battery energy storage system is running, in order to prevent the air from affecting the energy unit of the liquid flow energy storage system - the electrolyte, the storage tank is usually filled with nitrogen to isolate the air. This requires that nitrogen be constantly replenished in the storage tank. However, nitrogen is a consumable, non-recyclable, and expensive.

[0007] The present application provides a liquid storage system with a pressure regulating function, the liquid storage system comprising: a liquid storage tank, wherein an air bag is arranged in the liquid storage tank 1;

[0008] The opening of the airbag 8 can be connected to the outside so that the volume of the airbag 8 can change with the pressure in the liquid storage tank 1, so that the pressure in the liquid storage tank 1 is always equal to the external atmospheric pressure.

[0009] Preferably, the opening of the airbag 8 is connected to the outside through a valve 9. Of course, the function of the present application can be achieved without providing the valve 9.

[0010] Preferably, the airbag 8 is arranged in the upper part of the liquid storage tank 1 .

[0011] Preferably, the upper inner portion of the liquid storage tank 1 has a support structure 10 , and the airbag 8 is disposed on the support structure 10 .

[0012] Preferably, a pressure pipeline is connected above the liquid storage tank 1 , and a breathing valve 7 and a ball valve 6 are installed on the pressure pipeline in sequence, and the ball valve 6 is arranged between the breathing valve and the liquid storage tank 1 .

[0013] Preferably, the outlet of the liquid storage tank 1 is connected to the electrolyte inlet of the flow battery 4 through the liquid storage tank outlet pipeline 2;

[0014] The electrolyte outlet of the liquid flow battery 4 is connected to the inlet of the liquid storage tank 1 through the liquid storage tank inlet pipeline 3.

[0015] Preferably, the lower portion of the liquid storage tank 1 is connected to a pressure sensor 5 .

[0016] A second aspect of the present application provides a working method of a liquid storage system with a pressure regulating function, the working method comprising the following steps:

[0017] When the pressure in the liquid storage tank 1 is lower than the external atmospheric pressure, the external air automatically enters the airbag 8, so that the pressure in the liquid storage tank 1 is equal to the external atmospheric pressure;

[0018] When the pressure in the liquid storage tank 1 is greater than the external atmospheric pressure, the gas in the liquid storage tank 1 compresses the volume of the airbag 8 so that the air in the airbag 8 is discharged to the outside, so that the pressure in the liquid storage tank 1 is equal to the external atmospheric pressure.

[0019] The airbag 8 is made of a pressure-sensitive, soft, airtight material, such as rubber, polyester, or polyurethane.

[0020] The principles of this application are as follows:

[0021] The material of the liquid storage tank 1 is generally pph material. In addition to meeting the liquid column pressure required for work, the liquid storage tank made of this material should also meet the additional pressure range of 5kPa to -3kPa "GB / T25197-2010, Static Normal Pressure Welding Thermoplastic Plastic Storage Tank". When the liquid flow battery is working, the electrolyte flows to the liquid flow battery 4 through the liquid storage tank outlet pipeline 2, and then returns to the liquid storage tank 1 through the liquid storage tank inlet pipeline 3 to complete the charging and discharging. A pressure sensor 5 is installed at the bottom of the liquid storage tank to detect the change of the liquid level in the liquid storage tank 1.

[0022] In order to ensure that the additional pressure range in the gas tank is within the range of 5kPa to -3kPa and to reasonably protect the liquid storage tank, a breathing valve 7 is installed on the upper part of the liquid storage tank, and the breathing valve 7 is separated by a ball valve 6, and the ball valve 6 is opened during operation. The opening pressure range of the breathing valve 7 is +1735Pa and -295Pa. When the additional pressure in the gas tank exceeds this range, the breathing valve 7 automatically opens to balance the pressure inside and outside the liquid storage tank. The suction pressure value of the breathing valve 7 is relatively low. According to national standards, there is only one suction opening pressure in the current domestic breathing valve 7 opening pressure grade table, namely -295Pa. When the additional pressure in the gas tank is not within the opening pressure range, it cannot be opened, which still causes the pressure in the liquid storage tank to be unstable. In addition, if only the breathing valve 7 is used, it is inevitable that air will directly enter the liquid storage tank, affecting the quality of the electrolyte.

[0023] Therefore, the present application adds a set of airbags 8 in the liquid storage tank. The pressure inside the liquid storage tank is balanced by the expansion and contraction of the airbags 8. When negative pressure is formed inside the liquid storage tank 1 due to the three reasons described in the background technology above, air enters the airbags 8 through the valve 9 to balance the pressure inside and outside the airbags 8, thereby making the pressure inside the liquid storage tank 1 equal to the external atmospheric pressure. When the pressure inside the gas storage tank 1 is positive pressure, the increase in the pressure outside the airbags 8 will reduce the volume of the airbags 8, discharge the air inside the airbags 8, and balance the pressure inside and outside the airbags 8 with the atmospheric pressure. The airbags 8 are placed on the support 10.

[0024] The material of the airbag 8 needs to be a material that will not affect the electrolyte when in contact with the electrolyte, and has a soft texture and is sensitive to pressure. For example, the material of the airbag 8 is similar to that of the automobile airbag, such as rubber, polyester or polyurethane. The application still retains the breathing valve 7 and its isolation ball valve 6 to prevent the additional pressure in the liquid storage tank 1 from being too large when the airbag 8 fails, causing damage to the liquid storage tank 1.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. In the present application, an airbag 8 is provided in the liquid storage tank 1, and the volume of the airbag 8 changes with the pressure in the liquid storage tank 1 to maintain the pressure in the liquid storage tank 1 stable.

[0027] 2. When the pressure in the liquid storage tank 1 changes, the air enters and exits the airbag 8 without contacting the electrolyte in the liquid storage tank 1. Therefore, the present application can effectively prevent the external air from directly entering the liquid storage tank 1 when the negative pressure in the liquid storage tank 1 exceeds the breathing valve inhalation opening pressure, and the breathing valve opens, causing the air to contact the electrolyte and the electrolyte to oxidize. In addition, the present application does not need to replenish nitrogen at any time during use, saving the cost of nitrogen.

[0028] 3. The breathing valve has an opening pressure range for activation. When the additional pressure in the gas tank is not within the opening pressure range, it cannot be opened, which still causes the pressure in the liquid tank to be unstable. After using the airbag 8 of the present application, the airbag 8 can adapt to any slight pressure change in the gas tank 1, and the pressure in the liquid tank 1 can always remain stable.

[0029] 4. The pressure variation range in the liquid storage tank 1 can be changed by changing the volume of the airbag 8, which is simple, convenient and unrestricted. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the structure of the liquid storage system with pressure regulation function of the present application.

[0031] Figure 2 This is a schematic diagram of the positions of the airbag device 8, valve 9, and support structure 10 of the present application.

[0032] List of reference numerals:

[0033] 1. Liquid storage tank, 2. Liquid storage tank outlet pipeline, 3. Liquid storage tank inlet pipeline, 4. Liquid flow battery, 5. Pressure sensor, 6. Ball valve, 7. Breathing valve, 8. Airbag device, 9. Valve, 10. Support structure. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below in conjunction with embodiments.

[0035] Those skilled in the art will appreciate that the following examples are only used to illustrate the present invention and should not be considered to limit the scope of the present invention. If no specific techniques or conditions are specified in the examples, the techniques or conditions described in the literature in the art or the product specifications are used. If the manufacturer of the materials or equipment used is not specified, they are all conventional products that can be purchased.

[0036] Those skilled in the art will appreciate that, unless expressly stated, the singular forms "one", "an", "said" and "the" used herein may also include plural forms. In the description of the present invention, unless otherwise specified, "plurality" means two or more. It should be further understood that the term "comprising" used in the specification of the present invention refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. It should be understood that when we refer to an element as being "connected" to another element, it may be directly connected to the other element, or there may be intermediate elements. In addition, the "connection" used here may include wireless connections.

[0037] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0038] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0039] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be connected, detachably connected, or integrated; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0041] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms should not be understood as necessarily referring to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0042] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as those generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as herein.

[0043] like Figure 1 , the present application provides a liquid storage system with a pressure regulating function, the liquid storage system comprising: a liquid storage tank 1, wherein an air bag 8 is arranged in the liquid storage tank 1;

[0044] The opening of the airbag 8 can be connected to the outside so that the volume of the airbag 8 can change with the pressure in the liquid storage tank 1 to maintain the pressure in the liquid storage tank 1 stable.

[0045] The opening of the airbag 8 is connected to the outside through a valve 9. Preferably, the valve 9 is a ball valve. When the airbag 8 is in use, the valve 9 is opened. When the airbag 8 is not in use, the valve 9 is opened.

[0046] The airbag 8 is arranged in the upper part of the liquid storage tank 1, preferably above the liquid level.

[0047] The upper inner part of the liquid storage tank 1 has a support structure 10, and the airbag 8 is arranged on the support structure 10. Of course, the function of the present application can also be achieved without the support structure 10 so that the airbag 8 floats on the liquid surface.

[0048] The top of the liquid storage tank 1 is connected with a pressure pipeline, on which a breathing valve 7 and a ball valve 6 are installed in sequence, and the ball valve 6 is arranged between the breathing valve and the liquid storage tank 1. This is to prevent the liquid storage tank from being damaged due to excessive additional pressure in the liquid storage tank when the air bag 8 fails. The ball valve 6 can also be replaced by any suitable one-way valve.

[0049] The outlet of the liquid storage tank 1 is connected to the electrolyte inlet of the flow battery 4 through the liquid storage tank outlet pipeline 2;

[0050] The electrolyte outlet of the liquid flow battery 4 is connected to the inlet of the liquid storage tank 1 through the liquid storage tank inlet pipeline 3.

[0051] The lower part of the liquid storage tank 1 is connected to a pressure sensor 5 .

[0052] The working method of the above-mentioned liquid storage system with pressure regulating function comprises the following steps:

[0053] When the pressure in the liquid storage tank 1 is lower than the external atmospheric pressure, the external air automatically enters the airbag 8, so that the pressure in the liquid storage tank 1 is equal to the external atmospheric pressure;

[0054] When the pressure in the liquid storage tank 1 is greater than the external atmospheric pressure, the gas in the liquid storage tank 1 compresses the volume of the airbag 8 so that the air in the airbag 8 is discharged to the outside, so that the pressure in the liquid storage tank 1 is equal to the external atmospheric pressure.

Claims

1. A liquid storage system with a pressure regulating function, characterized in that: The liquid storage system comprises: a liquid storage tank (1), wherein an air bag (8) is arranged in the liquid storage tank (1); The opening of the airbag (8) can be connected to the outside world so that the volume of the airbag (8) can change with the pressure in the liquid storage tank (1), so that the pressure in the liquid storage tank (1) is always equal to the external atmospheric pressure.

2. The liquid storage system with pressure regulating function according to claim 1, characterized in that: The opening of the air bag (8) is connected to the outside through a valve (9).

3. The liquid storage system with pressure regulating function according to claim 1, characterized in that: The air bag (8) is arranged in the upper part of the liquid storage tank (1).

4. The liquid storage system with pressure regulating function according to claim 1, characterized in that: The upper inner portion of the liquid storage tank (1) is provided with a support structure (10), and the air bag (8) is arranged on the support structure (10).

5. The liquid storage system with pressure regulating function according to claim 1, characterized in that: A pressure pipeline is connected above the liquid storage tank (1), and a breathing valve (7) and a ball valve (6) are installed on the pressure pipeline in sequence. The ball valve (6) is arranged between the breathing valve and the liquid storage tank (1).

6. The liquid storage system with pressure regulating function according to claim 1, characterized in that: The outlet of the liquid storage tank (1) is connected to the electrolyte inlet of the liquid flow battery (4) through the liquid storage tank outlet pipeline (2); The electrolyte outlet of the liquid flow battery (4) is connected to the inlet of the liquid storage tank (1) through a liquid storage tank inlet pipeline (3).

7. The liquid storage system with pressure regulating function according to claim 1, characterized in that: The lower part of the liquid storage tank (1) is connected to a pressure sensor (5).

8. A working method of a liquid storage system with a pressure regulating function, characterized in that: The working method comprises the following steps: When the pressure in the liquid storage tank (1) is lower than the external atmospheric pressure, external air automatically enters the airbag (8), so that the pressure in the liquid storage tank (1) is equal to the external atmospheric pressure; When the pressure in the liquid storage tank (1) is greater than the external atmospheric pressure, the gas in the liquid storage tank (1) compresses the volume of the airbag (8) so that the air in the airbag (8) is discharged to the outside, so that the pressure in the liquid storage tank (1) is equal to the external atmospheric pressure.

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