A salt cavern flow battery system

Abstract

The present application relates to the field of fuel cells and their manufacturing technology, and in particular to a salt cavern flow battery system, comprising a stack; n positive salt caverns for separately storing positive electrode electrolytes of different valence states, and m negative salt caverns for separately storing negative electrode electrolytes of different valence states; the positive electrode of the stack and the n positive salt caverns are connected in series via a pipe to form a first closed loop; the negative electrode of the stack and the m negative salt caverns are connected in series via a pipe to form a second closed loop; a first pusher is provided in the first closed loop to push the positive electrode electrolyte to circulate in the first closed loop; a second pusher is provided in the second closed loop to push the negative electrode electrolyte to circulate in the second closed loop. The salt cavern flow battery system provided by the present application can improve the charge and discharge energy density of the salt cavern flow battery system.

Description

Technical Field

[0001] The present application relates to the technical field of fuel cells and their manufacturing, and in particular to a salt cavern flow battery system. Background Art

[0002] Liquid flow batteries using sodium chloride as the supporting electrolyte are crucial for the large-scale application of clean, renewable energy. Salt caverns are artificial underground caverns formed in underground salt formations using solution mining. Salt cavern flow battery systems use salt caverns as electrolyte storage tanks, saving significant land costs. However, due to the large size of salt caverns, the concentration distribution of high-valent active substances produced by the positive electrode and low-valent active substances produced by the negative electrode during charging is extremely uneven. This results in a low energy density during discharge, which cannot meet the needs of power users.

[0003] Therefore, how to improve the energy density of salt cavern flow battery systems is a technical problem that needs to be solved urgently. Summary of the Invention

[0004] The present application solves the technical problem of how to improve the energy density of a salt cavern flow battery system by providing a salt cavern flow battery system.

[0005] The salt cavern flow battery system comprises:

[0006] A battery stack, including a positive electrode and a negative electrode;

[0007] Salt caverns, comprising n positive electrode salt caverns for separately storing positive electrode electrolytes of different valence states; and m negative electrode salt caverns for separately storing negative electrode electrolytes of different valence states; wherein n and m are both positive integers greater than or equal to 2;

[0008] The positive electrode of the battery stack and the n positive electrode salt caverns are connected in series via pipes to form a first closed loop; the negative electrode of the battery stack and the m negative electrode salt caverns are connected in series via pipes to form a second closed loop;

[0009] A first pusher is provided in the first closed loop for pushing the positive electrode electrolyte to circulate in the first closed loop; a second pusher is provided in the second closed loop for pushing the negative electrode electrolyte to circulate in the second closed loop.

[0010] Furthermore, the first pusher and the second pusher include: a circulation pump arranged in the pipeline, and an isolation medium arranged in the salt cavern.

[0011] Furthermore, the density of the isolation medium is lower than that of the positive electrode electrolyte and the negative electrode electrolyte.

[0012] Furthermore, the isolation medium includes one or more of nitrogen or oil.

[0013] Furthermore, the positive electrode electrolyte includes a positive electrode active material and a sodium chloride supporting electrolyte; the negative electrode electrolyte includes a negative electrode active material and a sodium chloride supporting electrolyte.

[0014] Furthermore, each of the salt caverns is connected to the ground through two vertical wells.

[0015] Furthermore, each of the salt caverns is connected to the ground by setting a vertical well and an inclined well.

[0016] Furthermore, each of the salt caverns is connected to the ground through a vertical well.

[0017] Furthermore, the pipeline is made of corrosion-resistant material.

[0018] Furthermore, the salt cavern flow battery system is connected to a power supply device for providing electrical energy to the salt cavern flow battery system.

[0019] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

[0020] The salt cavern flow battery system provided in an embodiment of the present invention includes: a battery stack, including a battery stack positive electrode and a battery stack negative electrode; a salt cavern, including n positive electrode salt caverns for separately storing positive electrode electrolytes of different valence states; and m negative electrode salt caverns for separately storing negative electrode electrolytes of different valence states; wherein n and m are both positive integers greater than or equal to 2; the battery stack positive electrode and the n positive electrode salt caverns are connected in series via pipes to form a first closed loop; the battery stack negative electrode and the m negative electrode salt caverns are connected in series via pipes to form a second closed loop; a first pusher is provided in the first closed loop for pushing the positive electrode electrolyte to circulate in the first closed loop; a second pusher is provided in the second closed loop for pushing the negative electrode electrolyte to circulate in the second closed loop. The present invention connects two or more salt caverns to the positive and negative electrodes of the battery stack to store the electrolyte before and after the chemical reaction. When the battery stack is charging, high-concentration oxides produced by the positive electrode of the battery stack and high-concentration reduced products produced by the negative electrode of the battery stack are obtained, so that the redox reaction can occur efficiently during the discharge process of the battery stack, thereby achieving the technical effect of improving the charging energy density of the salt cavern liquid flow battery system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be construed as limiting the present invention. Throughout the accompanying drawings, the same reference figures represent the same components.

[0022] In the attached figure:

[0023] Figure 1 This is a structural schematic diagram of the salt cavern flow battery system provided in Example 1 of the present invention.

[0024] Figure 2 This is a structural diagram of the salt cavern flow battery system provided in Example 2 of the present invention.

[0025] Figure 3 This is a structural diagram of the salt cavern flow battery system provided in Example 3 of the present invention. DETAILED DESCRIPTION

[0026] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0027] Example 1

[0028] The embodiments of the present application provide a salt cavern flow battery system, which solves the technical problem of how to improve the energy density in the salt cavern flow battery system in the prior art.

[0029] To solve the above technical problems, the salt cave flow battery system provided in the embodiment of the present application includes:

[0030] The stack is provided with a positive electrode and a negative electrode. The stack is a device that provides electrolyte for electrochemical reaction and changes the valence state of the electrolyte entering the stack. In this embodiment, the stack is placed on the ground.

[0031] The salt cavern includes n positive electrode salt caverns for separately storing positive electrode electrolytes of different valence states; and m negative electrode salt caverns for separately storing negative electrode electrolytes of different valence states; wherein n and m are both positive integers greater than or equal to 2. In this embodiment, n and m are both set to 2. As an optional implementation, in actual applications, n and m are determined based on actual usage requirements and the actual capacity of the salt caverns, and are not limited here.

[0032] The positive electrode of the battery stack and the two positive salt caverns are connected in series via a pipe to form a first closed loop; the negative electrode of the battery stack and the two negative salt caverns are connected in series via a pipe to form a second closed loop; a first pusher is provided in the first closed loop to push the positive electrode electrolyte to circulate in the first closed loop, and a second pusher is provided in the second closed loop to push the negative electrode electrolyte to circulate in the second closed loop.

[0033] Specifically, the pipeline includes a transmission pipeline connecting the battery stack and the salt cavern, and a connecting pipeline used to connect two positive salt caverns or two negative salt caverns.

[0034] The first pusher and the second pusher include: a circulation pump disposed within the transmission pipeline, and an isolation medium disposed within the salt cavern. The circulation pump is arranged on the transmission pipeline and is used to promote the circulation of electrolyte within the transmission pipeline. The isolation medium has a lower density than the positive and negative electrolytes and does not react with the electrolytes. The isolation medium functions to push electrolyte from another salt cavern into the transmission pipeline through the transmission pipeline, thereby reaching the fuel cell stack for reaction. The transmission pipeline is arranged between salt caverns at the same level and is used to transport the isolation medium.

[0035] In this embodiment, for the two positive electrode salt caverns, one of the positive electrode salt caverns stores a low-valent positive electrode electrolyte, which includes a positive electrode active material and a sodium chloride (NaCl) supporting electrolyte. The low-valent positive electrode electrolyte passes through the transmission pipeline to the fuel cell stack, where it undergoes an oxidation reaction to produce a high-valent positive electrode electrolyte. The high-valent positive electrode electrolyte then passes through the transmission pipeline into the other positive electrode salt cavern.

[0036] Similarly, for two anode salt caverns, one anode salt cavern stores a high-valent anode electrolyte, which includes an anode active material and a sodium chloride (NaCl) supporting electrolyte. The high-valent anode electrolyte passes through the transmission pipeline to the stack, where it undergoes a reduction reaction to produce a low-valent anode electrolyte. The low-valent anode electrolyte then passes through the transmission pipeline to the other anode salt cavern.

[0037] The salt cavern flow battery system obtains its required electrical energy through a power supply device connected to the battery stack. As an optional implementation, the power supply device employed in this embodiment includes a power grid, which is used to control the output voltage and transmit and distribute electrical energy to the battery stack.

[0038] In order to better understand the above technical solution, the above technical solution will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0039] First, the term "and / or" as used herein simply describes a relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A alone, A and B together, or B alone. Furthermore, the character " / " in this document generally indicates an "or" relationship between the associated objects.

[0040] As attached Figure 1 As shown, when the power supply device 101 outputs electrical energy, the energy is transmitted to the battery stack 106 via the power grid 102. At this point, the salt cavern flow battery system is in a charging state. At the positive end, the circulation pump 105 transports the low-valent positive electrolyte 110-1 from the low-valent positive electrolyte salt cavern 112-1 to the battery stack 106 via the transmission pipe 107. An oxidation reaction occurs to generate a high-valent positive electrolyte 110-2, which the circulation pump 105 then transports via the transmission pipe 107 to the high-valent positive electrolyte salt cavern 112-2 for storage. As the high-valent positive electrolyte 110-2 enters, it squeezes the isolation medium 109 in the high-valent positive electrolyte salt cavern 112-2 and enters the low-valent positive electrolyte salt cavern 112-1 through the connecting pipe 108, causing the low-valent positive electrolyte 110-1 to flow again through the transmission pipe 107 to the fuel cell stack 106, where it continues to undergo an oxidation reaction to generate high-valent positive electrolyte 110-2, and this cycle repeats. Similarly, at the negative end, the circulation pump 105 transports the high-valent negative electrolyte 111-1 in the high-valent negative electrolyte salt cavern 113-1 to the fuel cell stack 106 through the transmission pipe 107, where it undergoes a reduction reaction to generate low-valent negative electrolyte 111-2. The circulation pump 105 then transports this through the transmission pipe 107 to the low-valent negative electrolyte salt cavern 113-2 for storage. As the low-valent negative electrode electrolyte 111-2 enters, it will squeeze the isolation medium 109 in the low-valent negative electrode electrolyte salt cavern 113-2 through the connecting pipe 108 and enter the high-valent negative electrode electrolyte salt cavern 113-1, so that the high-valent negative electrode electrolyte 111-1 will flow into the fuel cell stack 106 again through the transmission pipe 107, and continue to undergo reduction reaction to generate low-valent negative electrode electrolyte 111-2, and this cycle will repeat.

[0041] During the discharge state, the electrolyte flow direction is opposite to that during the charge state. At the positive end, the circulation pump 105 transports the high-valent positive electrolyte 110-2 in the high-valent positive electrolyte salt cavern 112-2 to the stack 106 via the transmission pipe 107, where a reduction reaction occurs to generate the low-valent positive electrolyte 110-1. The circulation pump 105 then transports this low-valent positive electrolyte 110-1 through the transmission pipe 107 to the low-valent positive electrolyte salt cavern 112-1. As the low-valent positive electrolyte 110-1 enters, it squeezes the isolation medium 109 in the low-valent positive electrolyte salt cavern 112-1 through the connecting pipe 108 and enters the high-valent positive electrolyte salt cavern 112-2. This causes the high-valent positive electrolyte 110-2 to flow again through the transmission pipe 107 to the stack 106, where it continues to undergo a reduction reaction to generate the low-valent positive electrolyte 110-1, and this cycle repeats. Similarly, at the negative end, the circulation pump 105 transports the low-valent negative electrode electrolyte 111-2 in the low-valent negative electrode electrolyte salt cavern 113-2 through the transmission pipe 107 to the fuel cell stack 106, where an oxidation reaction occurs to generate a high-valent negative electrode electrolyte 111-1. The circulation pump 105 then transports this high-valent negative electrode electrolyte 111-1 through the transmission pipe 107 to the high-valent negative electrode electrolyte salt cavern 113-1. As the high-valent negative electrode electrolyte 111-1 enters, it squeezes the isolation medium 109 in the high-valent negative electrode electrolyte salt cavern 113-1 through the connecting pipe 108 and enters the low-valent negative electrode electrolyte salt cavern 113-2, causing the low-valent negative electrode electrolyte 111-2 to flow again through the transmission pipe 107 to the fuel cell stack 106, where it continues to undergo an oxidation reaction to generate a high-valent negative electrode electrolyte 111-1, and this cycle repeats.

[0042] Specifically, the electrolytes for both the positive and negative electrodes are sodium chloride (NaCl) solution as the supporting electrolyte. The materials of the transmission pipe 107 and the connecting pipe 108 should have a certain degree of corrosion resistance. The isolation medium 109 is usually nitrogen or oil, which is used to isolate the electrolytes of different valence states and push the electrolytes of different valence states into the transmission pipe 107. Its density is lower than that of the electrolyte, so it does not affect the electrochemical properties of the electrolyte and does not corrode the surrounding rock of the salt cavern. The construction method of the salt cavern is the drilling and water dissolution method.

[0043] It is understood that in the embodiment of the present invention, there are two salt caverns at each end of the positive electrode and the negative electrode, but this is merely exemplary and does not constitute a limitation on the specific number of salt caverns at both ends of the positive electrode and the negative electrode in the embodiment of the present invention. When the salt cavern flow battery system needs to increase the energy storage time, the number of salt caverns at both ends of the positive electrode and the negative electrode can be increased, for example, to 4 or 8 or other numbers. In this way, long-term energy storage can be achieved without changing the existing salt cavern flow battery system. The outlet of the connecting pipe 108 is located at the top of the salt cavern, and the outlet of the transmission pipe 107 is located at the bottom of the salt cavern.

[0044] In this embodiment, each salt cavern is connected to the surface via two vertical wells. Specifically, two vertical wells are first drilled from the surface toward the target salt cavern. Transmission pipes 107 are inserted into the two vertical wells in each salt cavern, and then the two vertical wells are connected via a connecting pipe. This method is called a dual vertical well combination.

[0045] Example 2

[0046] Based on the same inventive concept, the second embodiment provides the following Figure 2 A salt cavern flow battery system is shown. Unlike Example 1, in this embodiment, each salt cavern is connected to the ground via a vertical well and an inclined well. Specifically, two wells are first drilled from the surface to reach the target salt layer: one vertical well and the other inclined well 114. Horizontal directional drilling technology is then used in the target salt cavern to connect the inclined well 114 to the bottom of the salt cavern, achieving docking and connection between the two wells. This method is called a combined vertical and inclined well.

[0047] Example 3

[0048] Based on the same inventive concept, Example 3 provides the following Figure 3 A salt cavern flow battery system is shown. Unlike Examples 1 and 2, in this embodiment, each salt cavern is connected to the surface via a vertical well. Specifically, a vertical well is first drilled from the surface to the target salt cavern, and multiple layers of casing are lowered. This method is called a single-well, multi-layer casing system.

[0049] In addition, abandoned salt caverns or salt mine resources can also be utilized and modified according to the above three embodiments to meet the requirements of the above three embodiments, thereby fully utilizing the existing abandoned salt caverns or salt mine resources.

[0050] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages: The high-power salt cave flow battery system provided by the present invention, by designing and constructing two or more salt caverns at each end of the positive electrode and the negative electrode to store the electrolyte before and after the chemical reaction, obtains a high concentration of oxides produced by the positive electrode during charging and a high concentration of reduced products produced by the negative electrode, so that the redox reaction can occur efficiently during the discharge process, which can enable the salt cave flow battery system to achieve a higher energy density. In addition, because the salt cavern itself contains a saturated sodium chloride (NaCl) solution, the salt cave flow battery system has the unique characteristics of low cost, large capacity, and economical land use, which is of great significance for the large-scale application of salt cave flow batteries. The high-power salt cave flow battery system provided by the present invention can significantly increase the concentration of oxides produced by the positive electrode during charging and reduced products produced by the negative electrode in the salt cavern, thereby achieving a higher energy density of the salt cave flow battery system during discharge, which can meet the needs of the power user, and will make an important contribution to the large-scale application of salt cave flow batteries.

[0051] The above is only an embodiment of the present application. Common knowledge such as the known specific structures and characteristics in the scheme is not described in detail here. Ordinary technicians in the relevant field are aware of all common technical knowledge in the technical field of the invention before the application date or priority date, can obtain all existing technologies in the field, and have the ability to apply conventional experimental means before that date. Ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the inspiration given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of this application, several variations and improvements can be made, which should also be regarded as the scope of protection of this application. These will not affect the effect of the implementation of this application and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A salt cavern flow battery system, characterized in that: include: A battery stack, including a positive electrode and a negative electrode; Salt caverns, comprising n positive electrode salt caverns for separately storing positive electrode electrolytes of different valence states; and m negative electrode salt caverns for separately storing negative electrode electrolytes of different valence states; wherein n and m are both positive integers greater than or equal to 2; The positive electrode of the battery stack and the n positive electrode salt caverns are connected in series via pipes to form a first closed loop; the negative electrode of the battery stack and the m negative electrode salt caverns are connected in series via pipes to form a second closed loop; A first pusher is provided in the first closed loop for pushing the positive electrode electrolyte to circulate in the first closed loop; a second pusher is provided in the second closed loop for pushing the negative electrode electrolyte to circulate in the second closed loop; The first pusher and the second pusher include: a circulation pump disposed in the pipeline, and an isolation medium disposed in the salt cavern; The isolation medium has a lower density than the positive electrode electrolyte and the negative electrode electrolyte; The isolation medium includes one or more of nitrogen and oil.

2. The salt cave flow battery system according to claim 1, characterized in that: The positive electrode electrolyte includes a positive electrode active material and a sodium chloride supporting electrolyte; the negative electrode electrolyte includes a negative electrode active material and a sodium chloride supporting electrolyte.

3. The salt cave flow battery system according to claim 1, characterized in that: Each of the salt caverns is connected to the ground through two vertical wells.

4. The salt cave flow battery system according to claim 1, wherein: Each salt cavern is connected to the ground by a vertical well and an inclined well.

5. The salt cave flow battery system according to claim 1, characterized in that: Each of the salt caverns is connected to the ground through a vertical well.

6. The salt cave flow battery system according to claim 1, characterized in that: The pipeline is made of corrosion-resistant material.

7. The salt cave flow battery system according to claim 1, characterized in that: The salt cavern flow battery system is connected to a power supply device for providing electrical energy to the salt cavern flow battery system.

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