Solution cooling system for flow battery

Abstract

The utility model belongs to the technical field of flow batteries, and particularly relates to a solution cooling system for a flow battery. According to the solution cooling system for the flow battery provided by the utility model, the compressor unit, the condenser, the refrigerant pump unit and the expansion valve which are connected in parallel are arranged on the heat exchanger, so that the solution cooling system is effective in electrolyte cooling operation, relatively simple in structure and relatively low in use and maintenance cost; and 2, a large external cooling device is not needed, so that the practicability is greatly improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of flow batteries, and particularly relates to a solution cooling system for a flow battery. Background Art

[0002] A flow battery refers to a redox battery, and its structural components mainly include: a stack, an electrolyte tank, and a pumping pipeline. Among them, the specific structure of the stack includes a housing, an ion diaphragm, and positive and negative electrodes. Two electrolyte pipelines flow on both sides of the ion diaphragm respectively, and finally an electric current can be output on the positive and negative electrodes.

[0003] Compared with relatively common lithium batteries, the advantages of flow batteries include: being resistant to large current charge and discharge, having an easy-to-adjust capacity, being capable of deep discharge, having reusable electrolytes, being able to achieve instant charging, and having a long service life. Therefore, the applicable scenarios of flow batteries mainly include: power generation systems, large charging stations, places with uninterrupted power supply, and various large industrial and mining enterprises.

[0004] On the other hand, the normal use of a flow battery also depends on a suitable electrolyte temperature. If the temperature of the above-mentioned electrolyte is too high, the electrolyte is likely to crystallize, ultimately reducing the battery performance. Therefore, existing common flow batteries generally come with an electrolyte cooling structure, that is, the above-mentioned solution cooling system.

[0005] For example, the Chinese utility model patent with the authorization announcement number CN216528969U and the authorization announcement date of May 13, 2022, discloses a cooling structure for a vanadium redox flow battery, including: a storage tank for accommodating the electrolyte; a cooling coil disposed in the storage tank; a cooling tower; a first cooling line connecting the cooling coil, and the first cooling line cools the cooling coil by exchanging heat with the cooling tower; a second cooling line connecting the cooling coil, and the second cooling line includes a refrigerating machine.

[0006] The general structural principle and advantages of the cooling structure in this utility model patent are as follows: On the basis of using a refrigerating machine, a cooling tower (such as a power plant cooling tower) is also introduced to cool the electrolyte of the vanadium redox flow battery. When in seasons with relatively low temperatures, all the electrolyte of the vanadium redox flow battery is cooled by the cooling tower, and the cooling capacity is large, which can adapt to high-power vanadium redox flow batteries, avoid starting the refrigerating machine, increase the power supply capacity, and be more energy-saving and environmentally friendly.

[0007] However, during the actual use process of this cooling structure, there are at least the following two deficiencies, which are also the technical problems to be solved by this utility model, namely:

[0008] First, its structural composition is relatively complex, including one refrigerating machine and two heat exchangers, thereby increasing the use and maintenance costs;

[0009] Second, its structural composition includes a cooling tower, which greatly limits its flexibility in use. In places without a cooling tower, this cooling structure is not applicable.

[0010] Therefore, in summary, there is an urgent need for a new cooling system with a relatively simple structure, high practicability, and a large applicable range to cool the electrolyte in the flow battery. Utility Model Content

[0011] The present utility model provides a solution cooling system for a flow battery. By setting a parallel compressor unit, a condenser, a parallel refrigerant pump unit, and an expansion valve on the heat exchanger, the following can be achieved: 1. The cooling operation of the electrolyte is effective, the structure is relatively simple, and the use and maintenance costs are relatively low; 2. Without relying on a large external cooling device, its practicability is greatly improved.

[0012] The technical solution adopted by the present utility model to solve the above problems is: a solution cooling system for a flow battery, the structure includes a heat exchanger, and also includes a parallel compressor unit, a condenser, a parallel refrigerant pump unit, and an expansion valve that are arranged between two refrigerant pipes and are connected in sequence through pipelines.

[0013] A further preferred technical solution lies in that: the parallel compressor unit includes a first check valve and a compressor that are connected in parallel.

[0014] A further preferred technical solution lies in that: the parallel compressor unit further includes a gas-liquid separator that is connected in series with the compressor and is connected in parallel with the first check valve.

[0015] A further preferred technical solution lies in that: the parallel refrigerant pump unit includes a second check valve and a delivery pump that are connected in parallel.

[0016] A further preferred technical solution lies in that: a refrigerant storage tank is further provided between the condenser and the parallel refrigerant pump unit.

[0017] A further preferred technical solution lies in that: insulating flanges are provided between the refrigerant pipe and the parallel compressor unit, and between the other refrigerant pipe and the expansion valve.

[0018] A further preferred technical solution lies in that: the condenser includes a heat exchange tube and a fan.

[0019] A further preferred technical solution lies in that: the two refrigerant pipes are respectively arranged at both ends of the inner tube of the heat exchanger.

[0020] A further preferred technical solution lies in that: the shape of the heat exchange tube is spiral or a rectangle with reciprocating bends.

[0021] A further preferred technical solution lies in that: the refrigerant allowing flow directions of the first one-way valve and the second one-way valve are the same. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic structural view of the present utility model.

[0023] Figure 2 are schematic views of three usage modes of the cooling system in the present utility model, wherein the "√" symbol represents the on-use state, and the "×" symbol represents the off-use state.

[0024] Figure 3 is a schematic view of the position and shape of the heat exchange tube in the reciprocating bending style in the present utility model.

[0025] Figure 4 is a schematic structural view of the parallel compressor unit in the present utility model.

[0026] Figure 5 is a schematic view of the position and structure of the parallel refrigerant pump unit in the present utility model.

[0027] Figure 6 is a schematic view of the position and structure of the heat exchanger in the present utility model.

[0028] In the figure, the meanings of the respective marks are as follows:

[0029] heat exchanger 11, refrigerant pipe 11-a, inner pipe 11-b of the heat exchanger, material pipe 11-c;

[0030] parallel compressor unit 1, condenser 2, parallel refrigerant pump unit 3, expansion valve 4, refrigerant storage tank 5, insulating flange 6;

[0031] first one-way valve 101, compressor 102, gas-liquid separator 103, second one-way valve 301, delivery pump 302, heat exchange tube 2-a, fan 2-b. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] The following is only a preferred embodiment of the present utility model, and does not limit the scope of the present utility model.

[0033] As shown in the Figure 1-6 accompanying drawings, a solution cooling system for a flow battery includes a heat exchanger 11, and also includes a parallel compressor unit 1, a condenser 2, a parallel refrigerant pump unit 3, and an expansion valve 4 that are arranged between two refrigerant pipes and are connected in sequence through pipelines.

[0034] In the prior art, the definitions of "parallel connection" and "series connection" are applicable not only to circuits, but also to liquid delivery pipelines and gas supply systems.

[0035] Therefore, in this embodiment, the parallel compressor unit 1 has the function that even if the compressor is shut down and deactivated, the entire cooling system pipeline can still operate smoothly. The same applies to the parallel refrigerant pump unit 3. Correspondingly, both the parallel compressor unit 1 and the parallel refrigerant pump unit 3 have two selectable states: "turned on and in use" and "turned off and deactivated".

[0036] In addition, the compressor, condenser 2, expansion valve 4, and heat exchanger 11 are all commercially available products, forming four phase change / heat exchange steps necessary for the refrigeration cycle pipeline. This allows the relatively high-temperature electrolyte to enter at one of the material pipes 11-c and exit at the other material pipe 11-c as the required relatively low-temperature electrolyte, ultimately ensuring that the electrolyte temperature of the flow battery always remains within a suitable range.

[0037] Furthermore, the entire cooling system not only has the advantages of relatively simple structure and relatively low use and maintenance costs, but also has the characteristic of not relying on external large cooling devices. Therefore, its practicality is relatively high.

[0038] Finally, the above-mentioned "solution" refers to the electrolyte of the flow battery.

[0039] The parallel compressor unit 1 includes a first check valve 101 and a compressor 102 that are connected in parallel with each other.

[0040] In this embodiment, the first check valve 101 is a commercially available product and is of the direct-through type.

[0041] The parallel compressor unit 1 further includes a gas-liquid separator 103 that is connected in series with the compressor 102 and in parallel with the first check valve 101.

[0042] In this embodiment, the gas-liquid separator 103 is a commercially available product, and its principle is to process the gas containing a small amount of condensate, recover the condensate, and purify the gas phase, thereby avoiding harmful liquid hammer phenomena in the compressor 102.

[0043] Among them, in the refrigerant flow direction, the gas-liquid separator 103 is located upstream of the compressor 102, thus enabling the above protection function to take effect.

[0044] Correspondingly, the usage methods of the parallel compressor unit 1 are as follows:

[0045] First, both the gas-liquid separator 103 and the compressor 102 are turned on and in use, and the refrigerant flows through these two in sequence, and the refrigerant does not pass through the first check valve 101;

[0046] Second, both the gas-liquid separator 103 and the compressor 102 are turned off and deactivated, and the refrigerant flows through the first check valve 101.

[0047] The parallel refrigerant pump unit 3 includes a second check valve 301 and a delivery pump 302 that are connected in parallel with each other.

[0048] In this embodiment, the second check valve 301 and the delivery pump 302 are also mutually exclusive in operation, that is, the refrigerant can only flow through one of them, ultimately making the compression refrigeration effect of the compressor 102 and the direct pumping effect of the delivery pump 302 independent of each other, and either can be selected between the states of being turned on for use and turned off for deactivation.

[0049] Specifically, reference can be made to the appendix Figure 2 , when the ambient temperature > 20 °C, the compressor 102 is turned on and the delivery pump 302 is turned off, and a relatively high-intensity compression refrigeration operation is directly carried out.

[0050] When the ambient temperature is between 10 °C and 20 °C, both the compressor 102 and the delivery pump 302 are turned on, and the compressor 102 is of a variable-frequency type with a wide frequency range, which can adapt to the wide-range variation of the heat load during the charge and discharge process of the electrolyte.

[0051] When the ambient temperature < 10 °C, the delivery pump 302 is turned on and the compressor 102 is turned off. At this time, the refrigeration intensity is relatively low, but it is completely sufficient. More importantly, the power of the delivery pump 302 is only about 15% of the power of the compressor 102. Therefore, the energy-saving effect is prominent in this mode.

[0052] Finally, through the above "three-gear" mode with different intensities, the entire cooling operation is sufficient and appropriate, and it has prominent energy-saving advantages.

[0053] A refrigerant storage tank 5 is also provided between the condenser 2 and the parallel refrigerant pump unit 3.

[0054] In this embodiment, the refrigerant used in this cooling system can be Freon. The main amount of refrigerant in the entire pipeline is stored in the refrigerant storage tank 5 and released as needed.

[0055] Insulating flanges 6 are provided between the refrigerant pipe and the parallel compressor unit 1, and between another refrigerant pipe and the expansion valve 4.

[0056] In this embodiment, the insulating flange 6 is a commercially available product. Its function is that even if the refrigerant pipe leaks at 11-a and thus accidentally leaks electricity, it will not cause the cooling pipeline to be electrified, thereby protecting the on-site operators. Among them, the above-mentioned Freon refrigerant itself is also non-conductive.

[0057] The condenser 2 includes heat exchange tubes and a fan.

[0058] In this embodiment, the condenser 2 adopts a fan type structure, ensuring sufficient and appropriate heat exchange, so that the refrigerant is converted into the low-temperature liquid required for cycle refrigeration after passing through the heat exchange tube.

[0059] The two refrigerant pipes are respectively arranged at both ends of the inner tube of the heat exchanger.

[0060] In the heat exchanger 11 of this embodiment, the refrigerant flows through the "inner tube", that is, the inner tube 11-b of the above heat exchanger, while the electrolyte flows through the "outer shell". One of the advantages of this method is that the heat exchanger 11 is connected to the electrolyte tank of the flow battery, and thus the flow battery can use a larger amount of electrolyte.

[0061] The shape of the heat exchange tube is spiral or a reciprocally bent rectangle.

[0062] In this embodiment, the spiral pattern is similar to a "mosquito coil shape", and the reciprocally bent rectangle can be referred to in the appendix Figure 3 Under the direct blowing action of the fan 2-b, both have sufficient cooling and heat exchange effects.

[0063] The refrigerant allowable flow directions of the first one-way valve 101 and the second one-way valve 301 are the same.

[0064] In this embodiment, the effective flow direction of the first one-way valve 101 and the second one-way valve 301 is the forward direction of the refrigerant flow in the entire cooling system.

[0065] The embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those of ordinary skill in the art, various modifications can be made without departing from the purpose of the present invention. These are all non-creative modifications and are protected by the patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A solution cooling system for a liquid flow battery, comprising a heat exchanger (11), characterized in that: It also includes a parallel compressor unit (1), a condenser (2), a parallel refrigerant pump unit (3), and an expansion valve (4) which are arranged between two refrigerant pipes and are sequentially connected by pipelines.

2. A solution cooling system for a flow battery according to claim 1, characterized in that: The parallel compressor unit (1) comprises a first one-way valve (101) and a compressor (102) which are connected in parallel with each other.

3. A solution cooling system for a flow battery according to claim 2, characterized in that: The parallel compressor unit (1) further comprises a gas-liquid separator (103) connected in series with the compressor (102) and in parallel with the first one-way valve (101).

4. A solution cooling system for a flow battery according to claim 2, characterized in that: The parallel refrigerant pump unit (3) comprises a second one-way valve (301) and a delivery pump (302) which are connected in parallel with each other.

5. A solution cooling system for a flow battery according to claim 1, characterized in that: A refrigerant storage tank (5) is also provided between the condenser (2) and the parallel refrigerant pump unit (3).

6. A solution cooling system for a flow battery according to claim 1, characterized in that: An insulating flange (6) is provided between the refrigerant pipe and the parallel compressor unit (1), and between another refrigerant pipe and the expansion valve (4).

7. A solution cooling system for a flow battery according to claim 1, characterized in that: The condenser (2) comprises a heat exchange tube and a fan.

8. A solution cooling system for a flow battery according to claim 1, characterized in that: The two refrigerant pipes are respectively arranged at two end positions of the inner pipe of the heat exchanger.

9. A solution cooling system for a flow battery according to claim 7, characterized in that: The shape of the heat exchange tube is a spiral shape or a reciprocatingly bent rectangle.

10. A solution cooling system for a flow battery according to claim 4, characterized in that: The first one-way valve (101) and the second one-way valve (301) allow the refrigerant to flow in the same direction.

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