TWI703759B - Storage module of distributed flow battery - Google Patents

Abstract

A storage module of distributed flow battery is provided. An electrochemical reaction is processed with the positive and negative electrolytes to produce and/or discharge direct current and further output the positive and negative electrolytes after the reaction. The module comprises two end plates; two frames disposed between the two end plates; two current collectors disposed between the two frames; two complex cast polar plates disposed between the two current collectors; two electrodes disposed between the two complex cast polar plates; a membrane disposed between the two electrodes; and three gaskets. Therein, two of the gaskets are set to sandwich and enclose one of the two complex cast polar plates; and the other one of the gaskets is set between the other one of the two complex cast polar plates and an adjacent one of the current collectors. Thus, the present invention is applied to distributed flow battery, where low-cost materials are used, including the membrane, plasma modified carbon felts, and the integrally-molded complex cast polar plates (composed of graphite plates and border plates with a new flow-field design); the bipolar plates are thinned with material cost effectively saved; and the present invention is used as a storage module in a form of combining the current collectors, the graphite plates, and the graphite papers to effectively improve the energy efficiency of cell stack.

Description

Distributed flow battery energy storage module

The present invention relates to a decentralized flow battery energy storage module, in particular to low utilization Cost-effective isolation membrane, plasma-modified carbon felt, and integrally formed composite casting plate (including graphite plate, frame and new flow field design), which can reduce the thickness of the bipolar plate, effectively save material costs, and serve as storage The energy module can effectively improve the energy efficiency of the battery stack in the combination of conductive plate, graphite plate and graphite paper.

All vanadium batteries use vanadium ions of different valences in the electrolyte to perform redox reactions To store or release electrical energy. The electrode itself does not participate in the reaction, and the electrolyte of the positive and negative electrodes are separated and stored in an external storage tank, so the self-discharge rate is low and the cycle life is long. Its characteristic is that battery power and stored energy can be designed separately.

The design of the battery structure needs to consider the distribution and reduction of the electrolyte in the reaction zone Shunt Current. The vanadium battery is composed of multiple single cells in series, and because the electrolyte is conductive, the electrolyte connecting any two single cells generates current due to the potential difference (ie, branch current). This current is not supplied to the external load. Need is a kind of internal friction. Most of the ways to reduce this branch current are to increase the length of the electrolyte flowing from the main channel to the reaction zone to increase the impedance of this part of the electrolyte. The flow channel is designed on the outer frame of the insulating material, thus increasing the complexity of the structure of the all-vanadium battery.

In the traditional structure of the all-vanadium battery, the bipolar plate is sandwiched by two insulating frames. It is made of an ink plate, in which the function of the graphite plate is to separate the positive and negative electrolytes and conduct electrons, and the branch flow channel is located on the insulating frame. When assembling, the contact surface of each layer must be equipped with airtight gaskets to prevent electrolyte leakage. However, this battery structure requires a large number of components and time-consuming assembly, which increases the cost of the battery. At the same time, the conventional bipolar plate has a large volume and is not easy to form an ultra-thin bipolar plate. As a result, after forming a battery pack, the battery pack is also bulky.

In view of the bipolar plate of the traditional flow battery, the graphite plate is sandwiched in the insulating frame, but this The bipolar plate of this design contains many parts, is large in size, and the assembly process takes a long time. Therefore, ordinary users cannot meet the needs of users in actual use.

The main purpose of the present invention is to overcome the above-mentioned problems encountered by conventional techniques and to provide Provides a kind of application in distributed flow battery, using low-cost isolation membrane, plasma-modified carbon felt, and integrally formed composite casting plate (including graphite plate, frame and new flow field design), which can combine bipolar The board is thinner, effectively saving material costs, and as an energy storage module, it is a distributed flow battery energy storage module that effectively improves the energy efficiency of the battery stack in the combination of conductive plates, graphite plates and graphite paper.

To achieve the above objectives, the present invention is a distributed flow battery energy storage module, which is based on According to the electrochemical reaction of the positive and negative electrode electrolytes to generate and/or release DC electric energy, and output the positive and negative electrode electrolytes after the reaction, it includes: two end plates, one of which has a negative electrode An input connector for one of the electrolyte sources, and an output connector that returns to the negative electrolyte source, and the other end plate has an input connector from a positive electrolyte source, and an output connector that returns to the positive electrolyte source器； Two frames (frame), set between the two end plates, is an insulating frame made of plastic material; two conductive plates (current collector), set between the two frames, each of the conductive plate front end is provided with a graphite Paper (graphite paper); two complex cast polar plates (complex cast polar plate), set between the two conductive plates, through casting molding method, a graphite plate (graphite plate) and a set on the graphite plate The frame is integrally formed at one time, and the composite cast electrode plate is a unipolar plate. The graphite plate is provided with several electrolyte flow channels on one side, and the conductive plate and the graphite plate with the electrolyte flow channels are connected through the graphite paper. On the contrary, the other side is in contact, the conductive plate, the graphite plate and the graphite paper are combined together, and the frame is provided with a plurality of branch flow channels and a plurality of manifold holes, and the branch flow channels of the frame It can guide the positive and negative electrolytes to flow into and out of the graphite plate; two electrodes are arranged between the two composite cast electrode plates, the two electrodes are respectively positive and negative electrodes, which are carbon felt modified by plasma ( carbon felt) as the electrode material; an isolation membrane (membrane) arranged between the two electrodes, and a polymer film modified by Atom Transfer Radical Polymerization (ATRP) as the membrane material; and three A leak-proof gasket (gasket), wherein two leak-proof gaskets are set to clamp one of the two composite casting electrode plates from the front and back, and the other leak-proof gasket is set on the other composite casting electrode plate and adjacent Between conductive plates.

In the above embodiment of the present invention, the graphite plate in the middle of the composite cast pole plate has a thickness At most 0.5 mm.

In the above embodiment of the present invention, the material of the frame includes polyvinyl chloride (PVC), Polyvinylidene fluoride (PVDF), polyethylene (PE), polypropylene (PP), polystyrene (PS) or polytetrafluoroethylene (PTFE).

In the above embodiment of the present invention, the isolation film will have polystyrene sulfonic acid The coating solution of (Polystyrene sulfonate, PSS) is applied to the porous polymer film for ATRP modification, using a peroxide to replace the hydrogen atoms in the polystyrene sulfonate film and polystyrene sulfonic acid into free radicals After the heating and polymerization reaction, the polymerized film and the polystyrene sulfonic acid are polymerized and cross-linked, so that the hydrophilic group can grow on the pores and surface of the polymerized film to improve the quality Highly hydrophilic isolation membrane.

In the foregoing embodiment of the present invention, the polysulfone film is polysulfone (Polysulfone, PSF), or Polyethersulfone (PES), which is modified by ATRP into PES-PSS or PSF-PSS with higher hydrophilic properties.

In the above embodiment of the present invention, the peroxide is sodium persulfate (Na ₂ S ₂ O ₈ ) or potassium persulfate (K ₂ S ₂ O ₈ ).

In the above embodiments of the present invention, the hydrophilic group is a sulfonate group (SO ₃ -).

Please refer to the "Figure 1 to Figure 4", which are the distributed liquid flow of the present invention. The schematic diagram of the structure of the pool energy storage module, the schematic plan view of the composite casting electrode plate of the present invention, the schematic diagram of the combination of the graphite plate and the conductive plate of the present invention, and the schematic diagram of the structure optimization test and verification results of the present invention. As shown in the figure: the present invention is a distributed flow battery energy storage module, which is based on the electrochemical reaction of the positive and negative electrode electrolytes to generate and/or release DC electric energy, and output the positive and negative electrode electrolytes after the reaction. It includes two end plates 1, 1a, two frames 2, two current collectors 3, two complex cast polar plates 4, two electrodes 5, and an isolation membrane ( membrane) 6, and three leak-proof gaskets (gasket) 7a, 7b, 7c.

The end plates 1, 1a mentioned above, one of the end plates 1 has a self-electrolysis One of the liquid source input connector 11, and return to the negative electrolyte source output connector 12, the other end plate 1a has an input connector 11a from a positive electrolyte source, and return to the positive electrolyte source An output connector 12a.

The two frames 2 are arranged between the two end plates 1, 1a, and are made of plastic insulation frame.

The two conductive plates 3 are arranged between the two frames 2, and the front end of each conductive plate 3 is provided with One graphite paper (graphite paper) 31.

The two composite casting electrode plates 4 are arranged between the two conductive plates 3, and are formed by casting In this way, a graphite plate 41 and a frame 42 provided on the graphite plate 41 are integrally formed at one time. The surface of the graphite plate 41 is provided with a number of electrolyte flow channels 411, and the graphite paper 31 makes the The conductive plate 3 is in contact with the graphite plate 41, the conductive plate 3, the graphite plate 41 and the graphite paper 31 are combined together, and the material of the frame 42 can be polyvinyl chloride (PVC) or polyvinylidene fluoride (PVDF), polyethylene (PE), polypropylene (PP), polystyrene (PS) or polytetrafluoroethylene (PTFE), on which there are several branch flow channels 421 and multiple manifold holes 422, and The branch flow channels 421 of the frame 42 can guide the positive and negative electrolytes to flow into and out of the graphite plate 41.

The two electrodes 5 are arranged between the two composite casting electrode plates 4, and the two electrodes 5 are respectively The positive and negative electrodes are made of carbon felt modified by plasma as the electrode material.

The isolation film 6 is arranged between the two electrodes 5. The isolation film 6 is made by applying a coating solution with polystyrene sulfonate (PSS) to a porous polymer film for modification by Atom Transfer Radical Polymerization (ATRP). The polysulfide film is polysulfone (PSF) or polyethersulfone (PES). Use sodium persulfate (Na ₂ S ₂ O ₈ ) or potassium persulfate (K ₂ S ₂ O ₈ ) as a peroxide, and take sodium persulfate with a concentration of 0.1 to 5.0 wt.% as an example to make the polymer The hydrogen atoms in the film and the polystyrene sulfonic acid containing the hydrophilic polymer structure are substituted into free radicals. After heating and polymerization, the polymer film is reacted at a temperature of 60-100°C for 1-24 hours. Polymerize and crosslink with the polystyrene sulfonic acid, so that the hydrophilic group-sulfonate group (SO ₃ -) can grow on the pores and surface of the polysulfonate film to be modified to a higher hydrophilic property The isolation film, such as PES-PSS or PSF-PSS.

The three leak-proof gaskets 7a, 7b, 7c, and the two leak-proof gaskets 7a, 7b are set It is set to clamp one of the two composite casting electrode plates 4 from the front and back, and the other leak-proof gasket 7c is arranged between the other composite casting electrode plate 4 and the adjacent conductive plate 3. If so, a brand-new distributed flow battery energy storage module is constructed through the above disclosed process.

The above composite casting plate 4 can be divided into unipolar plates or bipolar plates due to different positions. Yu Yishi In the embodiment, the bipolar plate means that the graphite plate 41 is provided with the electrolyte flow channels 411 on both sides; when used, the combination of the above-mentioned conductive plate 3, graphite plate 41 and graphite paper 31 is as follows: As shown in Figure 3 (a), the graphite plate 41 is a bipolar plate with electrolyte flow channels 411 on both sides. Through the structure optimization test and verification results, it can be seen that the structure with electrolyte flow channels on both sides will make the assembled battery stack have a higher contact resistance during operation, as shown in the horizontal bar graph in Figure 4. .

In another embodiment, the unipolar plate means that the graphite plate 41 is provided with the plurality of Electrolyte flow channel 411, and through the graphite paper 31 to make the conductive plate 3 and the electrolyte flow The opposite side of the graphite plate 41 of the channel 41 is in contact; when used, the combination of the above-mentioned conductive plate 3, graphite plate 41 and graphite paper 31 is shown in Figure 3 (b), where the graphite plate 41 is a single-sided design The unipolar plate with electrolyte flow channel 411, that is, the side of the graphite plate 41 and the graphite paper 31 corresponding to the graphite paper 31 is not provided with a flow channel structure. According to the results of structural optimization test and verification, the structure with electrolyte flow channel 411 on one side has lower contact resistance, which enables the assembled battery stack to operate at high current density and still have high energy. Efficiency, as shown in the twill bar graph in Figure 4.

In this way, the present invention is applied to a distributed flow battery, using a low-cost isolation membrane, electricity Pulp-modified carbon felt, and integrally formed composite casting plate (including graphite plate, frame and new flow field design), which can reduce the thickness of the bipolar plate to only 0.5 mm, effectively saving material costs and serving as energy storage The module effectively improves the energy efficiency of the battery stack in the combination of conductive plate, graphite plate and graphite paper.

In summary, the present invention is a decentralized flow battery energy storage module, which can effectively improve The conventional shortcomings are applied to distributed flow batteries, using low-cost isolation membranes, plasma-modified carbon felt, and integrally formed composite casting plates (including graphite plates, frame and new flow field design), The bipolar plate can be thinned, effectively saving material costs, and used as an energy storage module to effectively improve the energy efficiency of the battery stack in the combination of conductive plates, graphite plates and graphite paper, thereby making the production of the present invention more advanced , It is more practical and more in line with the needs of users, and it has indeed met the requirements of an invention patent application. A patent application is filed in accordance with the law.

However, the above are only preferred embodiments of the present invention, and should not be limited by this The scope of implementation of the present invention; therefore, all simple equivalent changes and modifications made in accordance with the scope of the patent application of the present invention and the content of the description of the invention should still fall within the scope of the patent of the present invention.

1, 1a: End plate 11, 11a: Input connector 12, 12a: output connector 2: Frame 3: Conductive plate 31: Graphite paper 4: Composite casting plate 41: Graphite board 411: Electrolyte flow path 42: Border 421: Branch runner 422: Manifold hole 5: Electrode 6: Isolation film 7a, 7b, 7c: leak-proof gasket

Figure 1 is a schematic diagram of the structure of the distributed flow battery energy storage module of the present invention. Figure 2 is a schematic plan view of the composite casting plate of the present invention. Figure 3 is a schematic diagram of the combination of the graphite plate and the conductive plate of the present invention. Figure 4 is a schematic diagram of the structure optimization test and verification results of the present invention.

1, 1a: end plate

11, 11a: input connector

12, 12a: output connector

2: frame

3: conductive plate

31: Graphite paper

4: Composite casting plate

41: Graphite board

411: Electrolyte flow channel

42: border

421: branch runner

422: Manifold hole

5: Electrode

6: Isolation film

7a, 7b, 7c: leak-proof gasket

Claims (7)

A distributed flow battery energy storage module is based on the electrochemical reaction of the positive and negative electrode electrolytes to generate and/or discharge direct current electric energy, and output the positive and negative electrode electrolytes after the reaction. It includes: two end plates (end plate), one of the end plates has an input connector from a negative electrolyte source and an output connector that returns to the negative electrolyte source, and the other end plate has an input connector from a positive electrolyte source , And return to one of the output connectors of the source of the positive electrolyte; two frames are arranged between the two end plates and are insulated frames made of plastic; two current collectors are arranged on the two frames In between, the front end of each conductive plate is provided with a graphite paper; two composite cast polar plates (complex cast polar plate) are set between the two conductive plates, and a graphite plate ( graphite plate) and a frame set on the graphite plate are integrally formed at one time. The composite casting plate is a unipolar plate. The graphite plate is provided with several electrolyte flow channels on a single side, and the graphite paper The conductive plate is in contact with the opposite side of the graphite plate with the electrolyte flow channels, and the conductive plates, the graphite plate and the graphite paper are combined together, and the frame is provided with several branch flow channels and multiple Two manifold holes, and the branch channels of the frame can guide the positive and negative electrolytes to flow into and out of the graphite plate; two electrodes are arranged between the two composite casting plates, and the two electrodes are respectively positive , Negative electrode, carbon felt (carbon felt) modified by plasma as the electrode material; a membrane (membrane), set between the two electrodes, using Atom Transfer Radical Polymerization (ATRP) ) Reformation Gathering A thin film is used as the membrane material; and three leak-proof gaskets, wherein the two leak-proof gaskets are set to clamp one of the two composite casting plates from the front and back, and the other leak-proof gasket is set on the other Between a composite cast pole plate and adjacent conductive plates. According to the distributed flow battery energy storage module described in item 1 of the scope of patent application, the thickness of the graphite plate in the middle of the composite casting electrode plate is at most 0.5 mm. According to the distributed flow battery energy storage module described in item 1 of the scope of patent application, the material of the frame includes polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), polyethylene (PE), and polypropylene (PP), polystyrene (PS) or polytetrafluoroethylene (PTFE). According to the distributed flow battery energy storage module described in item 1 of the scope of patent application, wherein the isolation membrane system applies a coating solution with polystyrene sulfonate (PSS) to the porous polymer The turbidity film is modified by ATRP. The hydrogen atoms in the turbidity film and polystyrene sulfonic acid are replaced by a peroxide to form free radicals. After heating and polymerization, the poly turbidity film and the poly Styrene sulfonic acid is polymerized and cross-linked so that hydrophilic groups can grow on the pores and surface of the polymer film to be modified into an isolation film with higher hydrophilic properties. According to the distributed flow battery energy storage module described in item 4 of the scope of patent application, wherein the polysulfone film is polysulfone (PSF) or polyethersulfone (PES), which is based on ATRP It is modified into PES-PSS or PSF-PSS isolation membrane with higher hydrophilic properties. According to the distributed flow battery energy storage module described in item 4 of the scope of patent application, the peroxide is sodium persulfate (Na ₂ S ₂ O ₈ ) or potassium persulfate (K ₂ S ₂ O ₈ ). Distributed according to the item 4 of the scope of patent flow battery energy storage module, wherein the hydrophilic group is a sulfonate based group (SO ₃ ^-).

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