All-vanadium redox flow battery stack module and all-vanadium redox flow battery

Abstract

The utility model discloses an all-vanadium redox flow battery electric pile module and an all-vanadium redox flow battery, and the all-vanadium redox flow battery electric pile module comprises an ionic membrane, a cover plate and a redox flow frame, an electrode cavity for accommodating a carbon felt electrode is formed in the liquid flow frame, the liquid flow frame is provided with a liquid inlet and a liquid outlet, the liquid flow frame is provided with a plurality of sub-runners communicated with the liquid inlet, and the sub-runners are used for enabling an electrolyte to form a plurality of sub-liquid flows to enter the carbon felt electrode; the cover plate is provided with a plurality of barrier strips arranged at intervals, and the barrier strips are used for making contact with the carbon felt electrodes so as to change the compression ratio of the carbon felt electrodes. According to the utility model, the electrolyte is shunted into a plurality of branch liquid flows through the branch runners and then enters the carbon felt electrode, so that the electrolyte is distributed more uniformly, and the carbon felt electrode has different compression ratios under the action of the barrier strips on the cover plate, so that the electrolyte flows more uniformly in the liquid flow frame, the polarization phenomenon of the electrode is effectively reduced, and the service life of the electrode is prolonged. The energy utilization rate of the battery is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of liquid flow batteries, in particular to an all-vanadium liquid flow battery stack module and an all-vanadium liquid flow battery. Background Art

[0002] Renewable energy sources, such as wind and solar, are unstable and discontinuous, requiring large-scale energy storage systems to connect their power to the grid. Among the available energy storage options, electrochemical energy storage technology is considered the most economical and practical. Among these electrochemical energy storage technologies, all-vanadium redox flow batteries have garnered widespread attention due to their high safety, separation of energy and power, long cycle life, and deep charge and discharge capabilities.

[0003] All-vanadium redox flow batteries are scaled up using a battery stack, consisting of multiple cells connected to an external fluid storage tank via a circulating pump. Currently, existing all-vanadium redox flow batteries suffer from uneven electrolyte distribution as the electrolyte flows through the carbon felt within the electrode frame due to flow resistance. This leads to severe polarization, which in turn can cause a decrease in battery capacity and hinders further application. Utility Model Content

[0004] In order to overcome the deficiencies of the prior art, the purpose of the present invention is to provide an all-vanadium liquid flow battery stack module and an all-vanadium liquid flow battery, which have the advantages of making the electrolyte distribution more uniform and improving the battery energy utilization efficiency.

[0005] The purpose of this utility model is achieved by the following technical solutions:

[0006] According to a first aspect of an embodiment of the present disclosure, there is provided an all-vanadium redox flow battery stack module, comprising:

[0007] An ion membrane, a cover plate symmetrically arranged on both sides of the ion membrane and in contact with the ion membrane, and a liquid flow frame symmetrically arranged on both sides of the ion membrane and in contact with the cover plate;

[0008] An electrode cavity for accommodating a carbon felt electrode is formed in the liquid flow frame. The liquid flow frame is provided with a liquid inlet and a liquid outlet. A side of the liquid flow frame facing the cover plate is provided with a plurality of branch channels connected to the liquid inlet. The branch channels are used to form a plurality of branch flows of the electrolyte before entering the carbon felt electrode.

[0009] The cover plate is provided with a plurality of spaced-apart baffles, and the baffles are used to contact the carbon felt electrode to change the compression rate of the carbon felt electrode.

[0010] To implement the above technical solution, the positive electrode electrolyte and the negative electrode electrolyte are respectively supplied from the two sides of the battery stack module, the ion membrane is used to separate the anions and cations, and the electrolyte enters the branch channel from the liquid inlet, and is divided into several branch flows by the branch channel and then enters the carbon felt electrode, so that the electrolyte distribution is more uniform. The effect of the baffle on the cover plate makes the carbon felt electrode have different compression rates, reducing the reaction dead zone of the carbon felt, and thus making the electrolyte flow more uniformly in the liquid flow frame, effectively reducing the electrode polarization phenomenon, improving the energy utilization rate of the battery, and enhancing the operating stability and service life of the battery stack.

[0011] In some exemplary embodiments, the flow channel includes:

[0012] a first flow channel connected to the liquid inlet;

[0013] a second flow channel connected to a side of the first flow channel away from the liquid inlet; and

[0014] A third flow channel is connected to at least two sides of the second flow channel, and the third flow channel is arranged near the edge of the electrode cavity. A side of the third flow channel close to the electrode cavity is provided with a plurality of spaced-apart dividing protrusions, and a liquid flow gap for the electrolyte to flow out is formed between adjacent dividing protrusions.

[0015] To implement the above technical solution, after the electrolyte enters the liquid inlet, it first converges through the first flow channel, and then is buffered and initially diverted by the second flow channel, so that the electrolyte is initially and evenly diverted to the third flow channel. Finally, the electrolyte is separated into several sub-flows by each separating protrusion and flows from the liquid flow gap to the carbon felt electrode, thereby making the electrolyte distribution more uniform.

[0016] In some exemplary embodiments, the first flow channel is connected to the middle portion of the second flow channel, and a plurality of the dividing protrusions are symmetrically distributed around the middle portion of the third flow channel.

[0017] Implementing the above technical solution can make the electrolyte evenly distributed in the entire electrode frame.

[0018] In some exemplary embodiments, the width of the first flow channel is consistent with the diameter of the liquid inlet, the width of the first flow channel is set to W1, and the width of the second flow channel is set to W2, wherein 2mm≤W1-W2≤6mm.

[0019] In some exemplary embodiments, the length of the separation protrusion is 2-500 mm, the width is 3-10 mm, and the interval between adjacent separation protrusions is 2-20 mm.

[0020] In some exemplary embodiments, the blocking bars are provided corresponding to the dividing protrusions.

[0021] In some exemplary embodiments, the thickness of the cover plate is 0.5-2 mm, and the width of the blocking bar is 10-30 mm.

[0022] In some exemplary embodiments, a sealing gasket is provided between the liquid flow frame, the cover plate and the ion membrane, and the thickness of the sealing gasket is 0.3-2 mm.

[0023] The above technical solution is implemented to improve the sealing of the battery stack module and reduce the occurrence of leakage.

[0024] In some exemplary embodiments, bipolar plates, current collecting plates, liquid inlet plates and end plates are stacked and sealed in sequence from the inside to the outside outside the liquid flow frame, and the bipolar plates, current collecting plates, liquid inlet plates and end plates are all provided with corresponding liquid inlets and liquid outlets.

[0025] According to a second aspect of an embodiment of the present disclosure, an all-vanadium liquid flow battery is provided, comprising a plurality of all-vanadium liquid flow battery stack modules as described in the first aspect, wherein the plurality of all-vanadium liquid flow battery stack modules are sequentially connected in series.

[0026] In summary, compared with the prior art, the present invention has the following beneficial effects:

[0027] An embodiment of the present invention provides an all-vanadium liquid flow battery stack module and an all-vanadium liquid flow battery, wherein the all-vanadium liquid flow battery stack module includes: an ion membrane, a cover plate symmetrically arranged on both sides of the ion membrane and in contact with the ion membrane, and a liquid flow frame symmetrically arranged on both sides of the ion membrane and in contact with the cover plate; an electrode cavity for accommodating a carbon felt electrode is formed in the liquid flow frame, the liquid flow frame is provided with a liquid inlet and a liquid outlet, and a side of the liquid flow frame facing the cover plate is provided with a plurality of branch channels connected to the liquid inlet, the branch channels are used to allow the electrolyte to form a plurality of branch flows and then enter the carbon felt electrode; a plurality of spaced-apart baffles are provided on the cover plate, the baffles are used to contact the carbon felt electrode to change the compression rate of the carbon felt electrode. The positive electrode electrolyte and the negative electrode electrolyte are respectively supplied from the two sides of the battery stack module. The ion membrane is used to separate the anions and cations. The electrolyte enters the branch channel from the liquid inlet, and is divided into several branch flows by the branch channel and then enters the carbon felt electrode, so that the electrolyte distribution is more uniform. The effect of the baffle on the cover plate makes the carbon felt electrode have different compression rates, reducing the reaction dead zone of the carbon felt, and making the electrolyte flow more evenly in the liquid flow frame, effectively reducing the electrode polarization phenomenon, improving the energy utilization rate of the battery, and improving the operating stability and service life of the battery stack. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a structural schematic diagram of an embodiment of the present utility model.

[0029] Figure 2 This is an exploded diagram of an embodiment of the present invention.

[0030] Figure 3 This is a schematic structural diagram of the liquid flow frame in an embodiment of the present utility model.

[0031] Figure 4 Schematic diagram of the structure of the cover plate in the embodiment of the present utility model.

[0032] The numbers and letters in the figure represent the corresponding component names:

[0033] 10. Ion membrane; 20. Cover plate; 21. Baffle; 30. Liquid flow frame; 31. Electrode cavity; 32. Liquid inlet; 33. Liquid outlet; 34. Branch channel; 341. First flow channel; 342. Second flow channel; 343. Third flow channel; 344. Separating bump; 345. Liquid flow gap; 40. Bipolar plate; 50. Current collecting plate; 60. Liquid inlet plate; 70. End plate. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0035] like Figures 1 to 4 As shown, the first aspect of the present invention provides an all-vanadium liquid flow battery stack module, comprising: an ion membrane 10, a cover plate 20 symmetrically arranged on both sides of the ion membrane 10 and in contact with the ion membrane 10, and a liquid flow frame 30 symmetrically arranged on both sides of the ion membrane 10 and in contact with the cover plate 20; an electrode cavity 31 for accommodating a carbon felt electrode is formed in the liquid flow frame 30, and a liquid inlet 32 ​​and a liquid outlet 33 are provided on the liquid flow frame 30. A plurality of branch channels 34 connected to the liquid inlet 32 ​​are provided on the side of the liquid flow frame 30 facing the cover plate 20, and the branch channels 34 are used to form a plurality of branch flows of the electrolyte and then enter the carbon felt electrode; a plurality of spaced-apart baffles 21 are provided on the cover plate 20, and the baffles 21 are used to contact the carbon felt electrode to change the compression rate of the carbon felt electrode.

[0036] Specifically, the branch channel 34 is symmetrically arranged on both sides of the liquid flow frame 30 along the width direction, and the branch channel 34 includes: a first flow channel 341 connected to the liquid inlet 32; a second flow channel 342 connected to the side of the first flow channel 341 away from the liquid inlet 32; and a third flow channel 343 connected to at least both sides of the second flow channel 342, the third flow channel 343 is arranged near the edge of the electrode cavity 31, and a plurality of spaced-apart dividing protrusions 344 are provided on the side of the third flow channel 343 close to the electrode cavity 31, and a liquid flow gap 345 for the electrolyte to flow out is formed between adjacent dividing protrusions 344; the first flow channel 341, the second flow channel 342 and the third flow channel 343 are all formed by grooves opened on the frame, and the depths of the first flow channel 341, the second flow channel 342 and the third flow channel 343 are the same.

[0037] After the electrolyte enters the liquid inlet 32, it first converges through the first flow channel 341, and then is buffered and initially diverted by the second flow channel 342, so that the electrolyte is initially and evenly diverted to the third flow channel 343. Finally, the electrolyte is separated into several sub-flows through the separation protrusions 344 and flows from the liquid flow gap 345 to the carbon felt electrode, thereby making the electrolyte distribution more uniform.

[0038] Among them, the first flow channel 341 is connected to the middle of the second flow channel 342, and the second flow channel 342 is also located in the middle position of the liquid flow frame 30, and its middle is aligned with the middle of the third flow channel 343. Several dividing protrusions 344 are symmetrically distributed with the middle of the third flow channel 343 as the center, so that the electrolyte can be evenly distributed in the entire electrode frame.

[0039] The width of the first flow channel 341 is consistent with the diameter of the liquid inlet 32. The width of the first flow channel 341 is set to W1 and the width of the second flow channel 342 is set to W2, wherein 2mm≤W1-W2≤6mm, and the preferred W1-W2 is 4mm. The diameter of the liquid inlet 32 ​​is set to 15mm, and the diameter of the liquid outlet 33 is 1.2-10mm larger than the diameter of the liquid inlet 32, preferably 6mm, that is, the preferred diameter of the liquid outlet 33 is 21mm, the width of the first flow channel 341 is 15mm, and the width of the second flow channel 342 is 11mm.

[0040] The thickness of the liquid flow frame 30 is set to 3-6mm, preferably 4.5mm, the length of the dividing protrusion 344 is 2-500mm and the width is 3-10mm, wherein the width is preferably 5mm, and the interval between adjacent dividing protrusions 344 is 2-20mm. The height of the dividing protrusion 344 is consistent with the depth of the third flow channel 343. In actual applications, the dividing protrusion 344 is set to different lengths, and the intervals between adjacent dividing protrusions 344 can also be set to different.

[0041] A slot corresponding to the electrode cavity 31 is provided in the middle of the cover plate 20, and the baffle 21 is arranged in the slot, and the cover plate 20 can completely cover the branch channel 34 to limit the flow of electrolyte to the carbon felt electrode. The thickness of the cover plate 20 is set to 0.5-2mm, preferably 1mm, and the width of the baffle 21 is set to 10-30mm, preferably 15mm. The baffle 21 is set corresponding to the partition protrusion 344.

[0042] At the same time, a sealing gasket (not shown in the figure) is provided between the liquid flow frame 30, the cover plate 20 and the ion membrane 10. The sealing gasket can be a silicone gasket with a thickness of 0.3-2 mm, preferably set to 0.5 mm, to improve the sealing of the battery stack module and reduce leakage.

[0043] Furthermore, outside the liquid flow frame 30, bipolar plates 40, current collecting plates 50, liquid inlet plates 60 and end plates 70 are stacked and sealed in sequence from the inside to the outside. Corresponding liquid inlets 32 and liquid outlets 33 are provided on the bipolar plates 40, current collecting plates 50, liquid inlet plates 60 and end plates 70. The bipolar plates 40, current collecting plates 50, liquid inlet plates 60 and end plates 70 can adopt the existing structure and will not be elaborated here.

[0044] The positive electrode electrolyte and the negative electrode electrolyte are respectively supplied from both sides of the battery stack module. The ion membrane 10 is used to separate the anions and cations. The electrolyte enters the branch channel 34 from the liquid inlet 32, and is divided into several branch flows by the branch channel 34 and then enters the carbon felt electrode, so that the electrolyte distribution is more uniform. The action of the baffle 21 on the cover plate 20 makes the carbon felt electrode have different compression rates, reducing the reaction dead zone of the carbon felt, and making the electrolyte flow more uniformly in the liquid flow frame 30, effectively reducing the electrode polarization phenomenon, improving the energy utilization rate of the battery, and improving the operating stability and service life of the battery stack.

[0045] A second aspect of an embodiment of the present invention provides an all-vanadium liquid flow battery, comprising a plurality of all-vanadium liquid flow battery stack modules as described in the first aspect, wherein the plurality of all-vanadium liquid flow battery stack modules are sequentially connected in series.

[0046] The present invention will be described below with reference to several specific embodiments:

[0047] Example 1

[0048] In this embodiment, the all-vanadium liquid flow battery includes 15 groups of all-vanadium liquid flow battery stack modules connected in series. In the all-vanadium liquid flow battery stack module, the thickness of the liquid flow frame 30 is 3.5 mm, the diameter of the liquid inlet 32 ​​is 15 mm, the diameter of the liquid outlet 33 is 6 mm larger than the diameter of the liquid inlet 32, the width of the first flow channel 341 is consistent with the diameter of the liquid inlet 32, the width of the second flow channel 342 is 4 mm less than the width of the first flow channel 341, and the length of the separating protrusion 344 on the third flow channel 343 is divided from the middle to the two sides. The spacings of the first flow channel 341 and the second flow channel 342 are 27.5mm, 30mm, 32.5mm, 40mm and 170mm respectively. The spacings between adjacent dividing protrusions 344 are 10mm, 7mm, 5mm and 3mm respectively. The width of the dividing protrusion 344 is 5mm. The thickness of the cover plate 20 is set to 1mm, the width of the baffle 21 is set to 15mm, the position of the baffle 21 is consistent with the position of the dividing protrusion 344, and are symmetrically distributed with the diversion point of the first flow channel 341 and the second flow channel 342 as the center. The thickness of the sealing gasket is 0.5mm.

[0049] Example 2

[0050] The only difference between this embodiment and the first embodiment is that in this embodiment, the width of the blocking bar 21 is set to 10 mm, and other conditions remain unchanged.

[0051] Example 3

[0052] The only difference between this embodiment and the first embodiment is that in this embodiment, the diameter of the liquid outlet 33 is 2 mm larger than the diameter of the liquid inlet 32 ​​, and other conditions remain unchanged.

[0053] Comparative Example

[0054] The only difference between this embodiment and the first embodiment is that in this embodiment, the thickness of the sealing gasket is 1 mm, and other conditions remain unchanged.

[0055] Performance tests were conducted on Example 1, Example 2, Example 3 and Comparative Example 1, and the test results are as follows:

[0056]

[0057] According to the test results, it can be seen that the performance of Example 1 is the best, while in Example 2, the width of the baffle is too small, which does not play a good blocking role, and the electrolyte in the battery stack will flow into each other, resulting in performance degradation; in Example 3, the diameter of the liquid outlet is too large, which makes the pressure in the battery stack too low and the reaction dead zone too large, resulting in worse performance; and in the comparative example, since the sealing gasket is too thick, the carbon felt electrode and the bipolar plate have poor contact and the contact resistance is too large, so the performance is the worst.

[0058] The above embodiments merely represent several implementation methods of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that those skilled in the art will be able to make various modifications and improvements without departing from the spirit of the present invention. These modifications and improvements are equivalent to those made to the above embodiments based on the essential technology of the present invention and fall within the scope of protection of the present invention.

Claims

1. An all-vanadium redox flow battery stack module, characterized in that: include: An ion membrane, a cover plate symmetrically arranged on both sides of the ion membrane and in contact with the ion membrane, and a liquid flow frame symmetrically arranged on both sides of the ion membrane and in contact with the cover plate; An electrode cavity for accommodating a carbon felt electrode is formed in the liquid flow frame. The liquid flow frame is provided with a liquid inlet and a liquid outlet. A side of the liquid flow frame facing the cover plate is provided with a plurality of branch channels connected to the liquid inlet. The branch channels are used to form a plurality of branch flows of the electrolyte before entering the carbon felt electrode. The cover plate is provided with a plurality of spaced-apart baffles, and the baffles are used to contact the carbon felt electrode to change the compression rate of the carbon felt electrode.

2. The all-vanadium redox flow battery stack module according to claim 1, characterized in that: The branch channel includes: a first flow channel connected to the liquid inlet; a second flow channel connected to a side of the first flow channel away from the liquid inlet; and A third flow channel is connected to at least two sides of the second flow channel, and the third flow channel is arranged near the edge of the electrode cavity. A side of the third flow channel close to the electrode cavity is provided with a plurality of spaced-apart dividing protrusions, and a liquid flow gap for the electrolyte to flow out is formed between adjacent dividing protrusions.

3. The all-vanadium redox flow battery stack module according to claim 2, characterized in that: The first flow channel is connected to the middle portion of the second flow channel, and a plurality of the dividing protrusions are symmetrically distributed with the middle portion of the third flow channel as the center.

4. The all-vanadium redox flow battery stack module according to claim 2 or 3, characterized in that: The width of the first flow channel is consistent with the diameter of the liquid inlet. The width of the first flow channel is set to W1, and the width of the second flow channel is set to W2, wherein 2mm≤W1-W2≤6mm.

5. The all-vanadium redox flow battery stack module according to claim 4, characterized in that: The length of the separation protrusion is 2-500 mm, the width is 3-10 mm, and the interval between adjacent separation protrusions is 2-20 mm.

6. The all-vanadium redox flow battery stack module according to claim 2, characterized in that: The blocking bars are arranged corresponding to the separating protrusions.

7. The all-vanadium redox flow battery stack module according to claim 1, characterized in that: The thickness of the cover plate is 0.5-2 mm, and the width of the blocking bar is 10-30 mm.

8. The all-vanadium redox flow battery stack module according to claim 1, characterized in that: A sealing gasket is provided between the liquid flow frame, the cover plate and the ion membrane, and the thickness of the sealing gasket is 0.3-2 mm.

9. The all-vanadium redox flow battery stack module according to claim 1, characterized in that: The liquid flow frame is further provided with bipolar plates, current collecting plates, liquid inlet plates and end plates stacked and sealed from the inside out, wherein the bipolar plates, current collecting plates, liquid inlet plates and end plates are provided with corresponding liquid inlets and liquid outlets.

10. An all-vanadium redox flow battery, characterized in that: It comprises several all-vanadium liquid flow battery stack modules according to any one of claims 1 to 9, and the several all-vanadium liquid flow battery stack modules are connected in series in sequence.

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