Self-adaptive sealed flow battery

Abstract

The invention relates to a self-adaptive sealing flow battery. The flow battery comprises a self-sealing electrolyte; the self-sealing electrolyte comprises a curing auxiliary agent, and the curing auxiliary agent is cured in the presence of oxygen. The flow battery provided by the invention can solve the problem that the leakage point cannot be repaired in time when the electric pile runs.

Description

Technical Field

[0001] This application relates to the field of flow battery technology, and more specifically, to an adaptively sealed flow battery. Background Technology

[0002] Flow batteries possess advantages such as high safety, long lifespan, large energy storage capacity, and adjustable power and capacity. They play a crucial role in ensuring stable output of new energy sources after storage and adjustment, enabling large-scale power management. However, the standard open-circuit voltage of a single flow battery cell is relatively low. To meet practical applications, a certain number of individual cells need to be connected in series to form a stack to obtain the required voltage. During battery operation, the flow and circulation of electrolyte in the stack, storage tank, and piping system are achieved through a pump system. However, due to the properties of the electrolyte and the design of the sealing and connection structures in flow batteries, electrolyte leakage is a common problem. Currently, the common method for sealing the electrolyte is to use internal sealing gaskets and external bolt reinforcement. External leakage of electrolyte during stack operation not only affects the performance of flow batteries but also leads to safety issues. Therefore, developing new sealing schemes and improving sealing reliability is of great significance to the development of flow batteries.

[0003] CN103840180A discloses a method of setting an annular line sealing groove on the electrode frame of a flow battery, wherein the intersection of the line sealing groove and the surface of the electrode frame consists of two annular lines. Although this method facilitates the installation of line sealing strips and reduces the probability of kinking and misalignment when installing sealing strips on the electrode frame surface, it has poor sealing effect at the common flow channel holes of the electrolyte and is prone to electrolyte leakage to the outside of the stack. Most importantly, it cannot promptly address leakage problems that may occur during operation. CN107123824A discloses a method of encapsulating the side of the stack perpendicular to the plane of the bipolar plates using an encapsulation end plate. The encapsulation end plate is made of polymer material and is encapsulated on the side of the stack perpendicular to the plane of the bipolar plates by physical or chemical means. Encapsulation methods include bonding, welding, chemical bonding, etc. While this solution provides a way to seal the battery in a flow battery stack without designing a sealing gasket, the bonding methods such as adhesive bonding and welding have a series of problems, including the inability to disassemble and reuse the stack after a single cell is damaged, and the inability to precisely match the positive and negative electrode frames, resulting in poor practicality. CN116053507A discloses a flow battery sealing structure with three layers of sealing. This solution increases the contact area between the sealing material and the membrane due to the presence of surface sealing, reducing the risk of membrane damage caused by line sealing stress and avoiding the risk of internal leakage in the stack. However, it cannot prevent leakage that may occur during the operation of the flow battery stack, and cannot promptly repair leaks that occur during stack operation. Summary of the Invention

[0004] The purpose of this disclosure is to provide an adaptively sealed flow battery to solve the problem that leaks cannot be repaired in a timely manner during battery stack operation.

[0005] To achieve the above objectives, this disclosure provides an adaptively sealed flow battery, the flow battery comprising a self-sealing electrolyte; the self-sealing electrolyte comprising a curing aid, the curing aid being cured in the presence of oxygen.

[0006] Optionally, the curing aid is selected from one or more of acrylic adhesives, polyurethane acrylate oligomers, and polyurethane acrylate prepolymers; Preferably, the acrylic adhesive includes one or more of acrylic acid and acrylate monomers; optionally, the degree of polymerization of the polyurethane acrylate oligomer is 2 to 5, preferably 3 to 4; and the degree of polymerization of the polyurethane acrylate prepolymer is 1 to 2, preferably 2.

[0007] Optionally, the content of the curing aid is 1 to 5% by weight, based on the total weight of the electrolyte.

[0008] Optionally, the content of the curing aid is 2-3% by weight, based on the total weight of the electrolyte.

[0009] Optionally, the electrolyte further includes an acid, a salt compound, and a solvent; the salt compound includes a metal salt and / or an ammonium salt.

[0010] Optionally, the metal salt is selected from one or more of vanadium salts, zinc salts, potassium salts, and sodium salts; optionally, the vanadium salt includes ammonium metavanadate; the total vanadium ion concentration in the electrolyte is 1.0~3.5 mol / L; optionally, the zinc salt includes zinc bromide; the concentration of zinc bromide in the electrolyte is 2.0~2.5 mol / L; optionally, the potassium salt includes potassium chloride; the concentration of potassium chloride in the electrolyte is 0.01~0.05 mol / L; optionally, the sodium salt includes sodium chloride; the concentration of sodium chloride in the electrolyte is 0.01~0.1 mol / L; optionally, the ammonium salt includes ammonium chloride; the concentration of ammonium chloride in the electrolyte is 0.01~0.1 mol / L.

[0011] Optionally, the acid is selected from one or both of sulfuric acid and hydrochloric acid; preferably, the acid content is 25-35% by weight, more preferably 28-33% by weight, based on the total weight of the electrolyte.

[0012] Optionally, the solvent includes deionized water; preferably, the solvent content is 55-70% by weight, based on the total weight of the electrolyte.

[0013] Optionally, the electrode frame surface of the flow battery is provided with two annular sealing grooves, and an elastic sealing element is provided in the annular sealing grooves.

[0014] Optionally, the material of the elastic sealing element is selected from one of EPDM rubber, fluororubber, polypropylene, and polytetrafluoroethylene.

[0015] Through the above technical solution, this disclosure provides an adaptive sealing flow battery. By adding a curing aid (such as an oxygen-loving adhesive) to the electrolyte, the curing aid is in a liquid state during normal flow battery operation. If leakage occurs during operation, the oxygen-loving adhesive is oxidized upon contact with air to form a solid and achieve sealing, thus enabling the self-repair of leaks during battery stack operation.

[0016] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0017] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram illustrating the effect of leak repair achieved by the flow battery provided in this disclosure after operation. Detailed Implementation

[0018] The following provides a detailed description of specific embodiments of this disclosure. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of this disclosure.

[0019] This disclosure provides an adaptively sealed flow battery, the flow battery comprising a self-sealing electrolyte; the self-sealing electrolyte comprising a curing aid, the curing aid being cured in the presence of oxygen.

[0020] This disclosure provides an adaptive sealing flow battery, which adds a curing agent (oxygen-loving adhesive) to the electrolyte. The curing agent is in a liquid state during normal flow battery operation. If leakage occurs during operation, the oxygen-loving adhesive is oxidized upon contact with air to form a solid and achieve sealing, thus enabling the self-repair of leaks during battery operation.

[0021] In a preferred embodiment, the curing aid is selected from one or more of acrylic adhesives, polyurethane acrylate oligomers, and polyurethane acrylate prepolymers; preferably, the acrylic adhesive includes one or more of acrylic acid and acrylate monomers; optionally, the degree of polymerization of the polyurethane acrylate oligomer is 2-5, preferably 3-4; the degree of polymerization of the polyurethane acrylate prepolymer is 1-2, preferably 2. Adding the curing aid provided in this embodiment to the electrolyte of the flow battery enables better response to oxygen for curing and leak sealing, resulting in better curing and repair effects.

[0022] In a preferred embodiment, the curing aid is selected from one or more aerobic acrylic adhesives. Using the preferred type of curing aid provided in this embodiment can achieve better adaptive repair and sealing effects.

[0023] In one embodiment, the content of the curing aid is 1-5% by weight, based on the total weight of the electrolyte. Adding the curing aid to the electrolyte according to the content in this embodiment can achieve a better leak repair effect.

[0024] In a preferred embodiment, the curing aid is present at a content of 2-3% by weight, more preferably 2-2.5% by weight, based on the total weight of the electrolyte. Adding the electrolyte to the electrolyte at the preferred content of this embodiment further improves the adaptive sealing effect of the flow battery.

[0025] In one embodiment, the electrolyte further includes an acid, a salt compound, and a solvent; the salt compound includes metal salts and / or ammonium salts, to achieve the function of a flow battery.

[0026] In one specific embodiment, the acid is selected from one or more of sulfuric acid and hydrochloric acid; preferably, it is sulfuric acid; preferably, the acid content is 25-35% by weight, more preferably 28-33% by weight, based on the total weight of the electrolyte. Adding acid to the electrolyte, especially adding acid at the concentration specified in this embodiment, can improve the active repair effect of leakage points in the flow battery.

[0027] In one specific embodiment, the metal salt is selected from one or more of vanadium salts, zinc salts, potassium salts, and sodium salts; optionally, the vanadium salt includes ammonium metavanadate; the total vanadium ion concentration in the electrolyte is 1.0~3.5 mol / L; optionally, the zinc salt includes zinc bromide; the concentration of zinc bromide in the electrolyte is 2.0~2.5 mol / L; optionally, the potassium salt includes potassium chloride; the concentration of potassium chloride in the electrolyte is 0.01~0.05 mol / L; optionally, the sodium salt includes sodium chloride; the concentration of sodium chloride in the electrolyte is 0.01~0.1 mol / L; optionally, the ammonium salt includes ammonium chloride; the concentration of ammonium chloride in the electrolyte is 0.01~0.1 mol / L. Adding salt compounds according to the concentrations specified in this embodiment can improve the performance of the flow battery.

[0028] All reagents used in this disclosure are available through ordinary commercial channels or can be prepared using known methods.

[0029] In one specific embodiment, the solvent includes deionized water; the solvent content is 55-70% by weight, based on the total weight of the electrolyte.

[0030] In one embodiment, the electrode frame surface of the flow battery has two annular sealing grooves, and an elastic sealing element is disposed in the annular sealing grooves. The battery provided in this disclosure also has an elastic sealing element on its exterior, which is in the shape of an "O" ring, to improve the battery's sealing effect.

[0031] In one specific embodiment, the width of a sealing groove at one side near the surface of the electrode frame is smaller than the width of a sealing groove between that side and the side away from the surface of the electrode frame, and the electrode, diaphragm, and electrode frame are sealed by O-rings.

[0032] In one specific embodiment, the material of the elastic sealing element is selected from corrosion-resistant and insulating rubber or plastic, wherein the rubber includes fluororubber and / or EPDM rubber; and the plastic includes polypropylene and / or polytetrafluoroethylene.

[0033] The present disclosure is further described in detail below through examples. All raw materials used in the examples are commercially available.

[0034] Example 1 The vanadium redox flow battery stack is 0.8m long, 0.5m wide, and 0.4m high. The stack consists of 50 individual cells connected in series. Based on the total weight of the electrolyte, the electrolyte includes: 30% sulfuric acid by weight, 1.7 mol / L vanadium salt (ammonium metavanadate, with a total vanadium ion concentration of 1.7 mol / L in the electrolyte), deionized water as the solvent (55% by weight), and 3% by weight of acrylic acid-based adhesive (curing aid). The sealing method adopts line sealing. There are two annular line sealing grooves on the surface of the electrode frame. The sealing line is made of EPDM rubber and is in the shape of an "O". The width of the sealing groove on the side closer to the surface of the electrode frame is smaller than the width of the sealing groove between the side closer to the surface of the electrode frame and the side farther away from the surface of the electrode frame. The O-rings are used to seal the electrode, diaphragm and electrode frame.

[0035] Before the fuel cell stack is put into operation, a sufficient amount of nitrogen is purged into the entire stack system to isolate the system from the outside air. This also ensures that the entire system is filled with electrolyte and free of air during cold operation before subsequent stack testing. The external environment of the fuel cell stack is oxygen-containing air.

[0036] The flow rate of the fuel cell stack during operation is 3m³. 3 / h, after one month of operation with no external leakage, observation of the fuel cell stack surface revealed some sealing points formed by aerobic adhesive solids, such as Figure 1 As shown.

[0037] The flow battery using this embodiment developed a leak after 29 days of operation and achieved adaptive repair. The flow battery can operate continuously for 60 days.

[0038] Comparative Example 1 The composition of the flow battery in this comparative example is similar to that of Example 1, except that no acrylic acid-based adhesive (curing aid) is added to the electrolyte; the rest of the process is the same as in Example 1.

[0039] The flow rate of the fuel cell stack during operation is 3m³. 3 / h, after one month of operation, external leakage appeared. Upon inspection of the fuel cell stack surface, some leakage points were found. These leakage points occurred between the sealing ring and the plate frame. The reason was that leakage points were caused by plate frame deformation or sealing ring creep during fuel cell stack operation.

[0040] The flow battery using this comparative example developed a leak after 15 days of operation and could not self-repair; the flow battery using this comparative example could operate continuously for 30 days.

[0041] Comparing Example 1 with Comparative Example 1, it can be seen that Example 1 uses the flow battery provided by this disclosure to achieve adaptive sealing, which can solve the leakage points caused by deformation during the operation of the fuel cell stack.

[0042] Example 2 This embodiment refers to the battery composition in Example 1, except that the acrylic oxygen-bonded adhesive (curing aid) is replaced with a polyurethane acrylate oligomer (degree of polymerization 3); the rest of the process is the same as in Example 1. The flow rate during stack operation is 3m³ / h. 3 / h.

[0043] A leak was detected after 28 days of operation and was automatically repaired; the flow battery using this embodiment can operate continuously for 58 days.

[0044] Comparing this embodiment with Embodiment 1, it can be seen that the use of acrylic oxygen-loving adhesive as a curing aid in Embodiment 1 can achieve a longer operating time.

[0045] Example 3 This embodiment refers to the battery composition in Embodiment 1, but differs from Embodiment 1 in that: The content of the acrylic component oxygen-based adhesive (curing aid) was adjusted to 1.5% by weight; the rest of the process was the same as in Example 1.

[0046] A leak was detected after 26 days of operation, and the battery automatically repaired itself; the flow battery using this embodiment can operate continuously for 56 days.

[0047] Comparing this embodiment with Embodiment 1, it can be seen that in Embodiment 1, the curing agent is added according to the preferred content provided in this disclosure, and the battery in Embodiment 1 has better adaptive repair capability and can maintain a longer operating cycle.

[0048] Example 4 This embodiment refers to the battery composition in Embodiment 1, but differs from Embodiment 1 in that: The content of the acrylic component oxygen-based adhesive (curing aid) was adjusted to 5% by weight; the rest of the process was the same as in Example 1.

[0049] A leak was detected after 20 days of operation, and the leak was automatically repaired. The flow battery using this embodiment can operate continuously for 50 days.

[0050] Comparing this embodiment with Embodiment 1, it can be seen that in Embodiment 1, the curing agent is added according to the preferred content provided in this disclosure, and the battery in Embodiment 1 has better adaptive repair capability and can maintain a longer operating cycle.

[0051] Example 5 This embodiment refers to the battery composition in Embodiment 1, but differs from Embodiment 1 in that: The composition of the electrolyte was adjusted to: 35% sulfuric acid by weight, 1.5 mol / L vanadium salt (the metal salt is ammonium metavanadate, and the total vanadium ion concentration in the electrolyte is 1.5 mol / L), water as the solvent, with a solvent content of 60% by weight, and 3% acrylic acid component oxygen-based adhesive (curing aid). The rest of the process was the same as in Example 1.

[0052] A leak occurred after 23 days of operation, but it completed its own repair; the flow battery using this embodiment can operate continuously for 54 days.

[0053] Comparing this embodiment with that of Embodiment 1, it can be seen that the composition of the electrolyte in Embodiment 1 is within the preferred range of this disclosure, and the battery in Embodiment 1 has a longer operating cycle.

[0054] Example 6 This embodiment refers to the battery composition in Embodiment 1, but differs from Embodiment 1 in that: The composition of the electrolyte was adjusted to: 25% sulfuric acid by weight, 2 mol / L vanadium salt (ammonium metavanadate, with a total vanadium ion concentration of 2.0 mol / L in the electrolyte), water as the solvent, with a solvent content of 65% by weight, and 3% acrylic acid component oxygen-based adhesive (curing aid). The remaining process was the same as in Example 1.

[0055] A leak occurred after 21 days of operation, but it completed its own repair; the flow battery using this embodiment can operate continuously for 51 days.

[0056] Comparing this embodiment with that of Embodiment 1, it can be seen that the composition of the electrolyte in Embodiment 1 is within the preferred range of this disclosure, and the battery in Embodiment 1 has a longer operating cycle.

[0057] Example 7 This embodiment refers to the battery composition in Embodiment 1, but differs from Embodiment 1 in that: The content of the acrylic component oxygen-based adhesive (curing aid) was adjusted to 8% by weight; the rest of the process was the same as in Example 1.

[0058] A leak was detected after 18 days of operation, and the battery automatically repaired itself. The flow battery using this embodiment can operate continuously for 35 days.

[0059] Comparing this embodiment with embodiments 3-4, it can be seen that in embodiments 3-4, the curing agent is added according to the optimized addition amount provided by this disclosure, and the battery in embodiments 3-4 has better adaptive repair ability and can maintain a longer operating cycle.

[0060] The preferred embodiments of this disclosure have been described in detail above. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0061] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0062] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. An adaptively sealed flow battery, characterized in that, The flow battery includes a self-sealing electrolyte; the self-sealing electrolyte includes a curing agent, which cures in the presence of oxygen.

2. The flow battery according to claim 1, characterized in that, The curing aid is selected from one or more of acrylic adhesives, polyurethane acrylate oligomers, and polyurethane acrylate prepolymers; preferably, the acrylic adhesive includes one or more of acrylic acid and acrylate monomers. Optionally, the degree of polymerization of the polyurethane acrylate oligomer is 2 to 5, preferably 3 to 4; the degree of polymerization of the polyurethane acrylate prepolymer is 1 to 2, preferably 2.

3. The flow battery according to claim 1, characterized in that, Based on the total weight of the electrolyte, the content of the curing aid is 1 to 5% by weight.

4. The flow battery according to claim 3, characterized in that, Based on the total weight of the electrolyte, the content of the curing aid is 2-3% by weight.

5. The flow battery according to claim 1, characterized in that, The electrolyte also includes acids, salt compounds and solvents; the salt compounds include metal salts and / or ammonium salts.

6. The flow battery according to claim 5, characterized in that, The metal salt is selected from one or more of vanadium salts, zinc salts, potassium salts, and sodium salts; Optionally, the vanadium salt includes ammonium metavanadate; the total vanadium ion concentration in the electrolyte is 1.0~3.5 mol / L; Optionally, the zinc salt includes zinc bromide; the concentration of zinc bromide in the electrolyte is 2.0~2.5 mol / L; Optionally, the potassium salt includes potassium chloride; the concentration of potassium chloride in the electrolyte is 0.01~0.05 mol / L; Optionally, the sodium salt includes sodium chloride; the concentration of sodium chloride in the electrolyte is 0.01~0.1 mol / L; Optionally, the ammonium salt includes ammonium chloride; the concentration of ammonium chloride in the electrolyte is 0.01~0.1 mol / L.

7. The flow battery according to claim 5, characterized in that, The acid is selected from one or both of sulfuric acid and hydrochloric acid; preferably, the acid content is 25-35% by weight, more preferably 28-33% by weight, based on the total weight of the electrolyte.

8. The flow battery according to claim 5, characterized in that, The solvent includes deionized water; preferably, the solvent content is 55-70% by weight, based on the total weight of the electrolyte.

9. The flow battery according to claim 1, characterized in that, The electrode frame surface of the flow battery is provided with two annular sealing grooves, and elastic sealing elements are provided in the annular sealing grooves.

10. The flow battery according to claim 9, characterized in that, The material of the elastic sealing element is selected from one of EPDM rubber, fluororubber, polypropylene and polytetrafluoroethylene.

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