System for filtering impurities in electrolyte of flow battery

Abstract

The utility model belongs to the technical field of flow batteries, and particularly relates to a flow battery electrolyte impurity filtering system. The impurity filtering system comprises an electric pile (13), a negative electrode liquid storage tank (11) and a positive electrode liquid storage tank (12); the system comprises a first mixed liquid filtering pipeline (05) and a second mixed liquid filtering pipeline (06), a first filtering device (7) and a first mixed liquid valve (1) are arranged on the first mixed liquid filtering pipeline (05), and a second filtering device (8) and a second mixed liquid valve (2) are arranged on the second mixed liquid filtering pipeline (06). According to the filtering system, the electrolyte does not pass through the flow battery in the filtering process, and the pipeline where the filtering device is located is an independent branch. After a pipeline valve where the filtering device is located is closed, pressure loss and flow of a liquid inlet pipeline of the flow battery and energy loss caused by a circulating pump are not affected, and the pressure loss and the energy loss of the pipeline can be reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of liquid flow batteries, and in particular relates to a liquid flow battery electrolyte impurity filtering system. Background Art

[0002] Large-scale, long-life, low-cost, and environmentally friendly are the main directions of energy storage technology development. Among various large-scale energy storage technology fields including pumped energy storage, compressed air energy storage, sodium sulfur batteries, lithium-ion batteries, lead-acid batteries, etc., all-vanadium liquid flow battery energy storage technology has become one of the preferred technologies for large-scale energy storage technology due to its long service life, safety and reliability, large energy storage scale, good battery uniformity, no pollution, fast response speed, and real-time direct monitoring of its charge and discharge status.

[0003] All-vanadium liquid flow batteries are mainly composed of battery stacks, electrolytes and electrolyte circulation systems. The electrolyte is the active substance of the electrochemical reaction of all-vanadium liquid flow batteries and the carrier of electrical energy. It is a key material of all-vanadium liquid flow batteries. Therefore, the quality of the electrolyte has a direct impact on the performance of all-vanadium liquid flow batteries. When the liquid flow battery system is in long-term operation, the electrolyte crystallization caused by residual impurities in new pipelines and liquid storage tanks and irregular operations, as well as impurities (carbon felt hair, dust, etc.) inside the newly assembled battery stack are easy to block the internal flow channel and carbon felt of the battery, affecting the passage of the electrolyte. At the same time, during the charging and discharging process, these impurities will have the risk of puncturing the ion membrane of the liquid flow battery, causing internal burning of the battery, reducing the health of the liquid flow battery, affecting efficiency, and shortening the service life. Therefore, it is very necessary to install an electrolyte filtration device in the liquid flow battery system.

[0004] The prior art generally performs filtering during the operation of the flow battery. For example, patent CN 220026247 U discloses a filtering device for a flow battery: in the filtering device for a flow battery, the electrolyte flows from the water inlet pipe toward the water outlet pipe, the water inlet pipe is filtered by the filtering component when passing through the filtering pipe, the filtered electrolyte flows back through the water outlet pipe, and is filtered by the filtering component during the flow of the electrolyte. This filtering method has the following disadvantages: 1. The device is installed at the water inlet pipe, and the electrolyte enters the flow battery after being filtered. Although it effectively filters the impurities in the electrolyte during operation, it also increases the flow resistance and generates a large pressure loss. 2. As the pressure loss of the pipeline increases, the pressure of the inlet and return pipelines also increases, which not only increases the workload of the circulation pump, but also causes energy consumption caused by the circulation pump, affecting the working efficiency of the flow battery.

[0005] In order to solve the above problems, this application is proposed. Utility Model Content

[0006] In the liquid flow battery electrolyte impurity filtering device of the present application, the electrolyte flows from the liquid inlet direction of the positive and negative electrode mixed liquid branches, and after being blocked by impurities and crystals by the filter, it flows into the return liquid pipeline and enters the liquid storage tank. During the normal operation of the liquid flow battery, the mixed liquid valve is closed, and the filtering device does not participate in the operation, which can effectively avoid the energy efficiency loss caused by the flow resistance of the filtering device. Therefore, under the premise that the energy consumption of the circulating pump is not increased and the flow rate of the electrolyte is not reduced, the present application installs a filter in the mixed liquid branch, which not only solves the problems of energy consumption, flow pressure loss, etc., but also facilitates the cleaning of the filter.

[0007] The present application provides a liquid flow battery electrolyte impurity filtration system, the impurity filtration system comprising: a battery stack 13, a negative electrode liquid storage tank 11, and a positive electrode liquid storage tank 12;

[0008] The outlet of the negative electrode liquid storage tank 11 is connected to the negative electrode electrolyte inlet of the battery stack 13 through the negative electrode liquid inlet pipeline 01, and the negative electrode electrolyte outlet of the battery stack 13 is connected to the inlet of the negative electrode liquid storage tank 11 through the negative electrode liquid outlet pipeline 02. The negative electrode liquid inlet pipeline 01 is provided with a negative electrode circulation pump 07 located upstream and a negative electrode battery stack liquid inlet valve 5 located downstream, and the negative electrode liquid outlet pipeline 02 is provided with a negative electrode battery stack liquid return valve 3;

[0009] The outlet of the positive electrode liquid storage tank 12 is connected to the positive electrode electrolyte inlet of the battery stack 13 through the positive electrode liquid inlet pipeline 03, and the positive electrode electrolyte outlet of the battery stack 13 is connected to the inlet of the positive electrode liquid storage tank 12 through the positive electrode liquid outlet pipeline 04. The positive electrode liquid inlet pipeline 03 is provided with a positive electrode circulation pump 08 located upstream and a positive electrode battery stack liquid inlet valve 6 located downstream, and the positive electrode liquid outlet pipeline 04 is provided with a positive electrode battery stack liquid return valve 4;

[0010] The impurity filtering system further includes: a first mixed liquid filtering pipeline 05 and a second mixed liquid filtering pipeline 06;

[0011] One end of the first mixed liquid filtering pipeline 05 is connected to the positive electrode liquid inlet pipeline 03 and the connection point is located between the positive electrode circulation pump 08 and the positive electrode stack liquid inlet valve 6, and the other end of the first mixed liquid filtering pipeline 05 is connected to the negative electrode liquid outlet pipeline 02 and the connection point is located downstream of the negative electrode stack liquid return valve 3. The first mixed liquid filtering pipeline 05 is provided with a first filtering device 7 and a first mixed liquid valve 1;

[0012] One end of the second mixed liquid filter pipeline 06 is connected to the negative electrode liquid inlet pipeline 01 and the connection point is located between the negative electrode circulation pump 07 and the negative electrode stack liquid inlet valve 5, and the other end of the second mixed liquid filter pipeline 06 is connected to the positive electrode liquid outlet pipeline 04 and the connection point is located downstream of the positive electrode stack liquid return valve 4. The second mixed liquid filter pipeline 06 is provided with a second filter device 8 and a second mixed liquid valve 2.

[0013] Preferably, the first filtering device 7 and the second filtering device 8 are both Y-type filters.

[0014] The present application also provides a method for filtering impurities in electrolyte of a flow battery, the filtering method comprising the filtering system of the first aspect, and the filtering method comprising the following steps:

[0015] Close the negative electrode stack liquid return valve 3, the negative electrode stack liquid inlet valve 5, the positive electrode stack liquid return valve 4, and the positive electrode stack liquid inlet valve 6, open the first liquid mixing valve 1 and the second liquid mixing valve 2, and start the negative electrode circulation pump 07 and the positive electrode circulation pump 08;

[0016] The electrolyte in the negative electrode liquid storage tank 11 flows to the positive electrode liquid storage tank 12 through the negative electrode liquid inlet pipeline 01, the second mixed liquid filtering pipeline 06 and the positive electrode liquid outlet pipeline 04, and the electrolyte is filtered by the second filtering device 8 while the mixed liquid is achieved;

[0017] The electrolyte in the positive electrode liquid storage tank 12 flows to the negative electrode liquid storage tank 11 through the positive electrode liquid inlet pipeline 03, the first mixed liquid filtering pipeline 05 and the negative electrode liquid outlet pipeline 02 to achieve liquid mixing, and the electrolyte is filtered by the first filtering device 7 at the same time.

[0018] The filtering scheme for this application can be any of the following:

[0019] 1. Start the filtration operation for the first time when the rack is newly assembled;

[0020] 2. Start filtering operation on the newly assembled battery stack;

[0021] 3. After running for a period of time, start filtering operation according to actual needs;

[0022] 4. Filter while the electrolyte mixture is being reduced.

[0023] The filtration system of the present application can effectively avoid contamination of the electrolyte and blockage of the flow channel by colloid residues in the pipeline, impurities inside the liquid storage tube, carbon felt inside the newly assembled battery stack, and other impurities.

[0024] In this application, the electrolyte flow direction in the pipeline is recorded as from upstream to downstream.

[0025] Compared with the prior art, this application has the following beneficial effects:

[0026] 1. In the filtration system of the present application, the electrolyte does not pass through the flow battery during the filtration process, and the pipeline where the filtration device is located is an independent branch. Closing the valve of the pipeline where the filtration device is located does not affect the pressure loss and flow rate of the flow battery inlet pipeline and the energy loss caused by the circulation pump, which can reduce the pipeline pressure loss and energy loss.

[0027] 2. When the valve of the pipeline where the filter device is located is closed, it is convenient for the operator to replace the filter cartridge and clean the filter cartridge, and clean the impurities and foreign matter in the filter without affecting the normal operation of the system.

[0028] 3. After the flow battery has been running for a period of time, the filtration operation can be started according to actual needs, or the filtration can be performed while the electrolyte mixture is being reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic structural diagram of the first embodiment of a liquid flow battery electrolyte impurity filtration system.

[0030] List of reference numerals:

[0031] 01. Negative electrode liquid inlet pipeline, 02. Negative electrode liquid outlet pipeline, 03. Positive electrode liquid inlet pipeline, 04. Positive electrode liquid outlet pipeline, 05. First mixed liquid filtration pipeline, 06. Second mixed liquid filtration pipeline, 07. Negative electrode circulation pump, 08. Positive electrode circulation pump, 11. Negative electrode storage tank, 12. Positive electrode storage tank, 13. Battery stack, 1. First mixing liquid valve, 2. Second mixing liquid valve, 3. Negative electrode battery stack return valve, 4. Positive electrode battery stack return valve, 5. Negative electrode battery stack inlet valve, 6. Positive electrode battery stack inlet valve, 7. First filter device, 8. Second filter device. DETAILED DESCRIPTION

[0032] The present application is further described in detail below in conjunction with embodiments.

[0033] Those skilled in the art will appreciate that the following examples are only used to illustrate the present application and should not be considered to limit the scope of the present application. 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.

[0034] Those skilled in the art will appreciate that, unless expressly stated otherwise, the singular forms "a", "an", "said" and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present application 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 herein may include wireless connections.

[0035] In the description of this application, unless otherwise specified, "plurality" means two or more. The terms "inside", "upper", "lower", etc. indicate positions or state relationships based on the positions or state relationships shown in the drawings, which are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operate in a specific position, and therefore cannot be understood as limiting this application.

[0036] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "provided with" 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 an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application are understood according to specific circumstances.

[0037] 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 to which this application 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.

[0038] The "range" disclosed in the present application is defined in the form of a lower limit and an upper limit, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of the particular range. The range defined in this way can be inclusive or exclusive of the end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a range. For example, if a range of 60 to 120 and 80 to 110 is listed for a particular parameter, it is understood that a range of 60 to 110 and 80 to 120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following ranges can all be expected: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4 and 2 to 5. In the present application, unless otherwise specified, the numerical range "a to b" represents an abbreviation of any real number combination between a and b, where a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0039] If not otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution. If not otherwise specified, all technical features and optional technical features of the present application can be combined with each other to form a new technical solution. If not otherwise specified, all steps of the present application can be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), indicating that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0040] If there is no special explanation, the "include" and "comprising" mentioned in this application are open-ended or closed-ended. For example, the "include" and "comprising" may mean that other components not listed may also be included or only the listed components may be included or only the listed components may be included.

[0041] If not specifically stated, in this application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B".

[0042] like Figure 1 , a liquid flow battery electrolyte impurity filtration system, the impurity filtration system comprises: a battery stack 13, a negative electrode storage tank 11, and a positive electrode storage tank 12;

[0043] The outlet of the negative electrode liquid storage tank 11 is connected to the negative electrode electrolyte inlet of the battery stack 13 through the negative electrode liquid inlet pipeline 01, and the negative electrode electrolyte outlet of the battery stack 13 is connected to the inlet of the negative electrode liquid storage tank 11 through the negative electrode liquid outlet pipeline 02. The negative electrode liquid inlet pipeline 01 is provided with a negative electrode circulation pump 07 located upstream and a negative electrode battery stack liquid inlet valve 5 located downstream, and the negative electrode liquid outlet pipeline 02 is provided with a negative electrode battery stack liquid return valve 3;

[0044] The outlet of the positive electrode liquid storage tank 12 is connected to the positive electrode electrolyte inlet of the battery stack 13 through the positive electrode liquid inlet pipeline 03, and the positive electrode electrolyte outlet of the battery stack 13 is connected to the inlet of the positive electrode liquid storage tank 12 through the positive electrode liquid outlet pipeline 04. The positive electrode liquid inlet pipeline 03 is provided with a positive electrode circulation pump 08 located upstream and a positive electrode battery stack liquid inlet valve 6 located downstream, and the positive electrode liquid outlet pipeline 04 is provided with a positive electrode battery stack liquid return valve 4;

[0045] The impurity filtering system further includes: a first mixed liquid filtering pipeline 05 and a second mixed liquid filtering pipeline 06;

[0046] One end of the first mixed liquid filtering pipeline 05 is connected to the positive electrode liquid inlet pipeline 03 and the connection point is located between the positive electrode circulation pump 08 and the positive electrode stack liquid inlet valve 6, and the other end of the first mixed liquid filtering pipeline 05 is connected to the negative electrode liquid outlet pipeline 02 and the connection point is located downstream of the negative electrode stack liquid return valve 3. The first mixed liquid filtering pipeline 05 is provided with a first filtering device 7 and a first mixed liquid valve 1;

[0047] One end of the second mixed liquid filter pipeline 06 is connected to the negative electrode liquid inlet pipeline 01 and the connection point is located between the negative electrode circulation pump 07 and the negative electrode stack liquid inlet valve 5, and the other end of the second mixed liquid filter pipeline 06 is connected to the positive electrode liquid outlet pipeline 04 and the connection point is located downstream of the positive electrode stack liquid return valve 4. The second mixed liquid filter pipeline 06 is provided with a second filter device 8 and a second mixed liquid valve 2.

[0048] The first filter device 7 and the second filter device 8 are both Y-type filters.

[0049] A method for filtering impurities in electrolyte of a flow battery, the filtering method adopting the above-mentioned filtering system, the filtering method comprising the following steps:

[0050] Close the negative electrode stack liquid return valve 3, the negative electrode stack liquid inlet valve 5, the positive electrode stack liquid return valve 4, and the positive electrode stack liquid inlet valve 6, open the first liquid mixing valve 1 and the second liquid mixing valve 2, and start the negative electrode circulation pump 07 and the positive electrode circulation pump 08;

[0051] The electrolyte in the negative electrode liquid storage tank 11 flows to the positive electrode liquid storage tank 12 through the negative electrode liquid inlet pipeline 01, the second mixed liquid filtering pipeline 06 and the positive electrode liquid outlet pipeline 04, and the electrolyte is filtered by the second filtering device 8 while the mixed liquid is achieved;

[0052] The electrolyte in the positive electrode liquid storage tank 12 flows to the negative electrode liquid storage tank 11 through the positive electrode liquid inlet pipeline 03, the first mixed liquid filtering pipeline 05 and the negative electrode liquid outlet pipeline 02 to achieve liquid mixing, and the electrolyte is filtered by the first filtering device 7 at the same time.

Claims

1. A liquid flow battery electrolyte impurity filtration system, characterized in that: The impurity filtering system comprises: a battery stack (13), a negative electrode liquid storage tank (11), and a positive electrode liquid storage tank (12); The outlet of the negative electrode liquid storage tank (11) is connected to the negative electrode electrolyte inlet of the battery stack (13) through a negative electrode liquid inlet pipeline (01), and the negative electrode electrolyte outlet of the battery stack (13) is connected to the inlet of the negative electrode liquid storage tank (11) through a negative electrode liquid outlet pipeline (02). The negative electrode liquid inlet pipeline (01) is provided with a negative electrode circulation pump (07) located upstream and a negative electrode battery stack liquid inlet valve (5) located downstream, and the negative electrode liquid outlet pipeline (02) is provided with a negative electrode battery stack liquid return valve (3); The outlet of the positive electrode liquid storage tank (12) is connected to the positive electrode electrolyte inlet of the battery stack (13) through a positive electrode liquid inlet pipeline (03); the positive electrode electrolyte outlet of the battery stack (13) is connected to the inlet of the positive electrode liquid storage tank (12) through a positive electrode liquid outlet pipeline (04); the positive electrode liquid inlet pipeline (03) is provided with a positive electrode circulation pump (08) located upstream and a positive electrode battery stack liquid inlet valve (6) located downstream; and the positive electrode liquid outlet pipeline (04) is provided with a positive electrode battery stack liquid return valve (4); The impurity filtering system further comprises: a first mixed liquid filtering pipeline (05) and a second mixed liquid filtering pipeline (06); One end of the first mixed liquid filtering pipeline (05) is connected to the positive electrode liquid inlet pipeline (03) and the connection point is located between the positive electrode circulation pump (08) and the positive electrode stack liquid inlet valve (6); the other end of the first mixed liquid filtering pipeline (05) is connected to the negative electrode liquid outlet pipeline (02) and the connection point is located downstream of the negative electrode stack liquid return valve (3); the first mixed liquid filtering pipeline (05) is provided with a first filtering device (7) and a first mixed liquid valve (1); One end of the second mixed liquid filtering pipeline (06) is connected to the negative electrode liquid inlet pipeline (01) and the connection point is located between the negative electrode circulation pump (07) and the negative electrode stack liquid inlet valve (5); the other end of the second mixed liquid filtering pipeline (06) is connected to the positive electrode liquid outlet pipeline (04) and the connection point is located downstream of the positive electrode stack liquid return valve (4); and a second filtering device (8) and a second mixed liquid valve (2) are provided on the second mixed liquid filtering pipeline (06).

2. The liquid flow battery electrolyte impurity filtration system according to claim 1, characterized in that: The first filtering device (7) and the second filtering device (8) are both Y-type filters.

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