CN109980260B

CN109980260B - Flow battery

Info

Publication number: CN109980260B
Application number: CN201910301646.6A
Authority: CN
Inventors: 张汉平; 周佩; 王亮; 张圣景; 程春雷
Original assignee: Changzhou University
Current assignee: Changzhou University
Priority date: 2019-04-16
Filing date: 2019-04-16
Publication date: 2023-03-24
Anticipated expiration: 2039-04-16
Also published as: CN109980260A

Abstract

The invention provides a flow battery, which consists of a positive electrode, a negative electrode, a grid, electrolyte and a shell. The positive electrode of the flow battery is subjected to intercalation-deintercalation reaction, the negative electrode is subjected to deposition-dissolution reaction, a diaphragm is not needed, stirring forced circulation is not needed, the rest parts except the pole piece can be made of the same material, and the flow battery has the characteristics of simple and compact structure, convenience in assembly and low cost.

Description

Flow battery

Technical Field

The invention belongs to the field of chemical power sources, and particularly relates to a flow battery.

Background

Flow batteries were an electrochemical energy storage device proposed in the 1970 s. The flow battery is different from other batteries in that the active substance of the flow battery is an electrolyte solution, so that the safety coefficient is high; but the energy density is lower due to limited solubility of the active.

Lithium ion batteries have a high energy density compared to other energy storage batteries, but their electrolytes are flammable carbonates, which are intrinsically not safe enough. Paper aquous cathode for next-generation Alkali-Ion Batteries (J.Am.chem.Soc., 2011 (133), 5756-5759.) and A hybrid redox flow battery with high energy utilization a low cost of a transmitted membrane as a separator and LiMn ₂ O ₄ as a cathode (j.mater.chem.a, 2013 (1), 14476-14479) combines a lithium ion battery with a flow battery, and proposes a liquid-solid mixed lithium ion flow battery, which uses an aqueous solution containing lithium ions as an electrolyte to solve the problem of flammability of an organic electrolyte, but it must use a diaphragm with ion exchange capacity, which is the same as that of a conventional flow battery, so that the cost is increased.

Rechargeable hybrid aqueous batteries (Journal of Power Sources,2012 (216), 222-226) and Binary ion batteries operating on The model of Newton's crops (Journal of The Electrochemical battery, 2012,159 (12), a2001-a 2004) report Binary cation flow batteries using metal as The negative electrode and conventional lithium ion battery positive electrode materials as The positive electrode active material, thereby avoiding The use of a separator, but since The energy density is limited by The solubility of The electrolyte as in conventional flow batteries, the volume of The electrolyte must be increased in order to increase The capacity. However, in order to reduce the resistance of the flow battery, the distance between the positive electrode and the negative electrode needs to be very close, which means that the electrolyte far away from the electrodes is difficult to migrate to the electrodes for discharging, so that the increased electrolyte is difficult to effectively act.

Patent CN 104716372A discloses a binary flow battery, which uses a circulating pump to force convection, so that electrolyte at a longer distance can also migrate to an electrode to discharge, and the problem of volume increase is well solved. But obviously increases the cost and is not conducive to miniaturization.

Disclosure of Invention

The invention aims to provide a flow battery which does not need a forced circulation system, is low in cost and is convenient to manufacture.

In order to achieve the purpose, the invention adopts the technical scheme that: a flow battery comprising a positive electrode, a negative electrode, a grid, an electrolyte, and a housing, wherein:

the positive pole and the negative pole are separated by a grid, the number of the grids is at least 1, and the existence of the grids ensures that the distance between the positive pole and the negative pole is 5 micrometers-10 millimeters. The positive electrode undergoes an intercalation-deintercalation reaction; the deposition-dissolution reaction of the cathode; the electrolyte is an aqueous electrolyte, which contains two or more conductive cations.

Preferably, the shape of the grid can be one or a combination of a plurality of shapes of sheets, nets, films, rods, threads, cylinders, bags and columns; the relative positions between the positive and negative electrodes and the grids can be one or more of parallel, vertical and net-shaped intersection; the thickness of the grid is between 5 microns and 10 millimeters.

Preferably, the positive electrode contains a positive electrode active material capable of generating a cation intercalation-deintercalation reaction, and the positive electrode active material comprises one or a mixture of more of lithium manganate, lithium cobaltate, lithium nickelate, lithium iron phosphate, a nickel-cobalt-aluminum ternary material, a nickel-cobalt-manganese ternary material, lithium vanadate, lithium titanate, a lithium-rich manganese material, sodium iron phosphate, a sodium ion superconductor, a sodium ion binary-ternary material (in the invention, a mixture of a sodium ion binary material and a sodium ion ternary material), prussian blue and derivatives thereof, and a polyanionic magnesium ion positive electrode material. The positive electrode is one or a combination of a plurality of sheet-shaped, net-shaped, film-shaped, rod-shaped, filiform, cylinder-shaped, bag-shaped and column-shaped electrodes, the shape of the positive electrode is adapted to the grid structure, and the positive electrode can be conveniently assembled on the grid structure.

Preferably, the negative electrode material is a mixture or a composite of one or more of aluminum, vanadium, chromium, manganese, iron, cobalt, zinc, nickel, copper, titanium, graphite or a graphite composite material; the negative electrode is in the shape of one or a combination of a plurality of sheet, net, film, rod, silk, cylinder, bag and column, and the shape of the negative electrode is adapted to the grid structure and can be conveniently assembled on the grid structure.

Preferably, one of the cations in the electrolyte is a cation which can be inserted and extracted in the positive electrode, and comprises lithium ions, sodium ions and magnesium ions; another is a cation that can be deposited or dissolved on the negative electrode, including a mixture of one or more of aluminum, vanadium, chromium, manganese, iron, cobalt, zinc, nickel, copper, titanium ions.

Preferably, the battery case and the grid may be made of a polymer material, including any one of polycarbonate, polyethylene, polypropylene, polyvinyl chloride, polymethyl methacrylate, polyamide, polylactic acid, polyurethane, polytetrafluoroethylene, polyphenylene sulfide, polyoxymethylene, or polyphenylene oxide.

Preferably, one or more of glass fiber, plant fiber, synthetic fiber, asbestos, paper or porous ceramic can be filled between the pole pieces. The electrolyte-rich battery is mainly filled between the positive plate and the negative plate, and for the electrolyte-rich battery, the filler can absorb the electrolyte, so that the pole plates are completely soaked by the electrolyte, and the reliability of the battery is improved.

Preferably, the aqueous electrolyte may further contain one or more of water-soluble starch, gelatin, polysaccharides (cellulose, alginic acid, hyaluronic acid, chitosan), polypeptides (collagen, poly-L-lysine, poly-L-glutamic acid), polyacrylamide, polyoxyethylene, polyacrylate, polyvinyl alcohol, sodium carboxymethylcellulose, sodium silicate, sodium metasilicate, sodium polyacrylate, acetic acid, ammonium chloride, disodium hydrogen phosphate, sodium dihydrogen phosphate, sulfuric acid, and citric acid.

Compared with the prior art, the invention has the beneficial effects that:

1) The electrolyte circulating system such as a circulating pump for circulating electrolyte, an electric motor and a liquid storage tank is eliminated, the positions of the pole pieces are fixed through the grids, micro-channels are formed between the pole pieces, the adverse effect of concentration polarization on the performance of the battery is eliminated at a minimum small distance, and the pole pieces are ensured not to be in contact with each other and short-circuited. The device has the characteristics of simple and compact structure, easy large-scale production, convenient assembly and low cost, and effectively improves the operation reliability.

2) While not wishing to be bound by any theory, the inventors believe that liquid phase mass transfer is often the controlling step for the electrode reactions of flow batteries, creating concentration polarization phenomena that affect battery performance. It is generally believed that the liquid phase mass transfer process satisfies the following equation:

t＝d ² /D

d is the molecular diffusion coefficient, D is the molecular diffusion distance, and t is the time required for the molecule to displace D in length completely by virtue of molecular thermal motion (molecular diffusion). Since the diffusion time t is proportional to the square term of the diffusion distance, the molecular diffusion time decreases sharply with the decrease of d, and when d is reduced to the minimum, the molecular diffusion time is almost negligible. In the flow battery, when the pole piece spacing limit is small, the liquid phase mass transfer is very fast, and the concentration polarization can be eliminated.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments or the prior art description will be briefly introduced, it is to be noted that the drawings are only for clearly showing the structure, and other features, objects and advantages of the present invention will become more apparent. It is to be understood that the drawings described below are merely exemplary of the invention and that other configurations may be obtained by those skilled in the art without the exercise of inventive faculty.

FIG. 1 is a plan view in the embodiment 1 of the present invention;

fig. 2 is a cut-away view of the flow battery of example 1;

FIG. 3 is a schematic view of a lattice structure in example 1;

FIG. 4 is a charge/discharge test chart of the battery of example 1;

FIG. 5 is a battery cycle performance test chart of example 1;

FIG. 6 is a schematic diagram of a grid structure in example 2 of the present invention;

FIG. 7 is a charge/discharge test chart of the battery of example 2;

FIG. 8 is a battery cycle performance test chart of example 2;

fig. 9 is a top view of a flow battery of example 3 of the present invention;

fig. 10 is a cut-away view of a flow battery of example 3;

FIG. 11 is a structural view of a mesh grid in embodiment 3;

FIG. 12 is a charge/discharge test chart of the battery according to example 3;

FIG. 13 is a battery cycle performance test chart of example 3;

fig. 14 is a top view of a flow battery of example 4 of the present invention;

fig. 15 is a cut-away view of a flow battery of example 4;

FIG. 16 is a structural view of a mesh grid in example 4;

FIG. 17 is a charge/discharge test chart of the battery of example 4;

FIG. 18 is a battery cycle performance test chart of example 4;

fig. 19 is a top view of a flow battery of example 5 of the present invention;

fig. 20 is a cut-away view of a flow battery of example 5;

FIG. 21 is a schematic view of a lattice structure in example 5;

FIG. 22 is a charge/discharge test chart of the battery of example 5;

FIG. 23 is a battery cycle performance test chart of example 5;

fig. 24 is a schematic view of a flow battery in example 6 of the invention;

FIG. 25 is a three-dimensional view of the grid in example 6;

FIG. 26 is a schematic view of the structure of the pole piece in example 6;

FIG. 27 is a charge/discharge test chart of the battery according to example 6;

FIG. 28 is a battery cycle performance test chart of example 6;

FIG. 29 is a perspective view of a grating of embodiment 7;

FIG. 30 is a charge/discharge test chart of the battery according to example 7;

FIG. 31 is a battery cycle performance test chart of example 7;

the labels in the figure are as follows: 1. the battery comprises a positive electrode, a negative electrode, an electrolyte storage tank, a grid and a shell, wherein the positive electrode is 2, the negative electrode is 3, the electrolyte storage tank is 4, and the shell is 5.

Detailed Description

The invention is described in more detail below with reference to the following examples:

example 1:

in this embodiment, as shown in fig. 1 and fig. 2, a flow battery includes a single battery, which includes a positive electrode 1, a negative electrode 2, an

electrolyte storage tank

3, and 2 grids 4 oppositely disposed at two sides of the electrolyte storage tank 3, and the electrolyte storage tank is filled with electrolyte. One of them grid is located between anodal and the electrolyte storage tank, and another grid is located between negative pole and the electrolyte storage tank, and the electrolyte storage tank is enclosed by battery case and two grids, but can not sealing connection between grid and the battery case, and anodal, 2 grids, negative pole are parallel arrangement each other. The active ingredient of the positive electrode is lithium manganate, and the pole piece is prepared by mixing an active substance, acetylene black and a binder according to the weight ratio of 80:10:10 is pressed on a nickel net to prepare the lithium ion battery, the negative electrode is a zinc sheet, and the electrolyte is an aqueous solution of lithium salt and zinc salt. The grid material is polycarbonate, and the grid structure is square slice shape, as shown in fig. 3, and thickness is 0.1mm, installs through the mode that inserts the casing and reserve the slot. The grid structure contains 4 bars on the horizontal direction, contains 2 straight bars on the vertical direction, and the width of bar is 1mm, and the bar interval of equidirectional is 10mm. Fig. 4 and fig. 5 show the results of the battery performance test of the battery, the first discharge capacity reaches 120mAh/g, and the charge-discharge efficiency is maintained above 98%.

Example 2

Referring to fig. 6, the difference between this embodiment and embodiment 1 is that the structure of the grid 4 is different, the grid material is polycarbonate, the grid 4 is square sheet, the thickness is 1mm, the grid is composed of a frame and internal grid holes, the grid holes are regular hexagons, the width of the grid bars is 1mm, and the frame width is 2mm. Fig. 7 and 8 show the results of the battery performance test of the battery, the first discharge capacity reaches 92mAh/g, the charge-discharge efficiency is maintained above 98%, and the capacity retention rate is high.

Example 3

In this embodiment, as shown in fig. 9 and 10, a flow battery includes a positive electrode 1, a negative electrode 2, an electrolyte storage tank 3, and a grid 4, where the electrolyte storage tank 3 is surrounded by a casing, the positive electrode 1 and the negative electrode 2, the grid 4 is located in the electrolyte storage tank and separates the positive electrode 1 and the negative electrode 2, and the electrolyte storage tank is filled with electrolyte. The active ingredient of the positive electrode is lithium manganate, and the pole piece is prepared by mixing an active substance, acetylene black and a binder according to the weight ratio of 80:10:10 is pressed on a nickel net to prepare the lithium ion battery, the negative electrode is a zinc sheet, and the electrolyte is an aqueous solution of lithium salt and zinc salt.

Referring to fig. 11, the grid is made of polycarbonate, the grid 4 is a net structure with a thickness of 1mm, and the grid 4 and the shell are integrally formed. The grid contains two parts, nodes such as column skeleton and spheroid, polyhedron, cylinder, and the spheroid is selected for use to this embodiment node, and the column skeleton guarantees that grid structure has certain mechanical strength, and the node then guarantees to have certain interval between positive and negative pole piece, can normally carry out electrochemical reaction, and does not take place the short circuit. The cross-sectional area of the framework is 1mm, the thickness of the nodes is 1mm, and the width of the frame is 2mm. Fig. 12 and 13 show the results of the battery performance test of the battery, the first discharge capacity reaches 97mAh/g, and the charge-discharge efficiency is maintained above 98%.

Example 4

This embodiment is a flow battery, as shown in fig. 14 and 15, including a cylindrical positive electrode 1, a cylindrical negative electrode 2, an electrolyte, 2 grids 4, and a case 5. The electrolyte is filled in the gaps among the positive electrode, the negative electrode, the grid and the case. The active ingredient of the positive electrode is lithium manganate, and the pole piece is prepared by mixing an active substance, acetylene black and a binder according to the weight ratio of 80:10:10 pressing the mixture on a nickel screen to obtain the lithium ion battery, wherein the negative electrode is a zinc sheet, and the electrolyte is an aqueous solution of lithium salt and zinc salt. The positive and negative electrode structures are cylinders with the diameter of 5mm.

The grid is made of polycarbonate, the grid structure is net-shaped, as shown in fig. 16, the thickness of the grid structure is 1mm, the grid structure is provided with a plurality of circular through holes, the diameters of the circular holes are slightly larger than those of the positive electrode and the negative electrode, the grid structure is provided with a plurality of grids in the direction perpendicular to the positive electrode and the negative electrode, and the distance between every two grids is 15mm. The cylindrical positive and negative poles are inserted into the circular holes of the 2 grids 4 arranged in parallel to be fixed, as shown in the cross-sectional view of fig. 9, the plane of the positive pole end face is 1mm higher than the plane of the negative pole end face on the upper part of the battery, all the positive pole end faces are connected into a whole through a conductor to be used as the positive pole of the battery, and all the negative pole end faces are connected into a whole through a conductor to be used as the negative pole of the battery. Fig. 17 and 18 show the results of the battery performance test of the battery, the first discharge capacity reaches 72mAh/g, the charge-discharge efficiency is kept above 98%, and the capacity is kept better.

Example 5

In this embodiment, as shown in fig. 19 and 20, a flow battery includes a positive electrode, a grid, a negative electrode, an electrolyte, and a case. The active ingredient of the positive electrode is lithium manganate, and the pole piece is prepared by mixing an active substance, acetylene black and a binder according to the weight ratio of 80:10:10 is pressed on a nickel net to prepare the lithium ion battery, the negative electrode is a zinc sheet, and the electrolyte is an aqueous solution of lithium salt and zinc salt.

The positive and negative plates are square sheets, as shown in fig. 21, the grid is made of polycarbonate, the grid structure is provided with a plurality of sheets in the direction perpendicular to the positive and negative plates, and the space between every two sheets of grids is 10mm. The grid is provided with pole piece grid holes for fixing the positive pole piece and the negative pole piece and grid holes between the pole pieces between two adjacent pole piece grid holes, the pole piece grid holes and the grid holes between the pole pieces are rectangular and are arranged in parallel, the grid holes for fixing the pole pieces are slightly larger than the cross sections of the pole pieces, and the width of the grid holes between the pole pieces is 1mm. The total number of the grids is 4, the grids are sequentially arranged from top to bottom at intervals, and the positive electrode and the negative electrode are jointly fixed by the 4 grids and are alternately inserted into the grid holes of the pole pieces. The main purpose of setting up the grid hole between the pole piece in this embodiment is for the lightweight of grid, reduces the material and uses. FIG. 22 and FIG. 23 show the results of the battery performance tests of the battery, the first discharge capacity of the battery reaches 74mAh/g, and the charge-discharge efficiency is maintained at 98% or more.

Example 6

In this embodiment, as shown in fig. 24, a flow battery includes a positive electrode, a grid, a negative electrode, an electrolyte, and a case. The active ingredient of the positive electrode is lithium manganate, and the pole piece is prepared by mixing an active substance, acetylene black and a binder according to the weight ratio of 80:10:10 is pressed on a nickel net to prepare the lithium ion battery, the negative electrode is a zinc sheet, and the electrolyte is an aqueous solution of lithium salt and zinc salt. Gaps are formed in the positive plate and the negative plate, as shown in fig. 26, the gap distance is 5mm, the gap length is half of the width of the plate, the gap width is slightly larger than the cross section of the plate, and the positive plate and the negative plate are arranged in a mutually crossed mode through the gaps. In order to prevent the positive and negative pole pieces from short circuit, an insulated grid structure is arranged at the intersection, the grid is made of polycarbonate, and the grid structure is parallel to the pole pieces. As shown in fig. 25, the grid structure is columnar, the middle of the grid structure is provided with a gap, the width of the gap is slightly larger than the thickness of the pole piece, the other three sides of the grid structure except the gap are provided with grooves, the depth of the left and right grooves is 2mm, and the thickness of the grooves is slightly larger than the thickness of the pole piece; the depth of the bottom groove is half of the width of the pole piece, and the thickness of the bottom groove is slightly larger than that of the pole piece. Fig. 27 and 28 show the results of the battery performance test of the battery, the first discharge capacity of the battery reaches 140mAh/g, the charge-discharge efficiency is maintained above 98%, and the capacity retention rate is good.

Example 7

A flow battery comprises a positive electrode, a grid, a negative electrode, an electrolyte and a shell. The active component of the positive electrode is lithium iron phosphate, the lithium iron phosphate, acetylene black and SBR binder are uniformly mixed into suspension according to the proportion of 80; taking a zinc wire with the diameter of 0.3mm as a negative electrode, and taking 10% of lithium sulfate and zinc sulfate aqueous solution as electrolyte; the high-density polypropylene container is a shell; a net shape was woven with a high density polypropylene thread having a diameter of 0.1mm as shown in fig. 29. And placing the anode and the cathode in a grid at intervals, wherein the grid is made of polycarbonate, and each section of the anode is adjacent to and insulated from the cathode. All the anode sections and all the cathode sections are respectively gathered together and are led out as an anode and a cathode. Fig. 30 and fig. 31 are battery performance test results of the battery, the first discharge capacity reaches 140mAh/g, the charge-discharge efficiency is maintained at more than 98%, and the capacity retention rate is high.

Claims

1. A flow battery comprises a positive electrode, a negative electrode, a grid, electrolyte and a shell, and is characterized in that: the grid is electrically non-conductive; the positive electrode undergoes an intercalation-deintercalation reaction; the negative electrode is subjected to deposition-dissolution reaction; the electrolyte is aqueous electrolyte, which contains more than two conductive cations; the positive electrode and the negative electrode are fixed by a grid;

the positive plate and the negative plate are integrally distributed in a grid shape and are separated and fixed by a grid, gaps are formed in the positive plate and the negative plate, the gap distance is 5mm, the length of each gap is half of the width of the plate, and the width of each gap is slightly larger than the cross section of the plate, so that the positive plate and the negative plate are arranged in a crossed mode through the gaps; in order to prevent the positive and negative pole pieces from short circuit, an insulated grid structure is arranged at the intersection and is parallel to the pole pieces; the grid structure is columnar, a gap is arranged in the middle of the grid structure, grooves are arranged on the other three side edges of the grid structure except the gap, the depth of the left and right grooves is 2mm, and the thickness of the left and right grooves is slightly larger than that of the pole piece; the depth of the bottom groove is half of the width of the pole piece, and the thickness of the bottom groove is slightly larger than that of the pole piece.

2. The flow battery of claim 1, wherein: the grating is one or a combination of a plurality of sheets, nets, films, rods, threads, cylinders, bags and columns; the relative position between the grid and the anode or the cathode is one or more of parallel, vertical and net-shaped intersection; the thickness of the grid is between 5 microns and 10 millimeters.

3. The flow battery of claim 1, wherein: the positive electrode contains an active material capable of generating cation intercalation-deintercalation reaction, and the active material comprises one or a mixture of more of lithium manganate, lithium cobaltate, lithium nickelate, lithium iron phosphate, nickel cobalt aluminum ternary material, nickel cobalt manganese ternary material, lithium vanadate, lithium titanate, lithium-rich manganese material, ferric sodium phosphate, sodium ion superconductor, sodium ion binary-ternary material, prussian blue and derivatives thereof and polyanionic magnesium ion positive electrode material; the shape of the positive electrode is one or a combination of a plurality of sheet-shaped, net-shaped, film-shaped, rod-shaped, thread-shaped, barrel-shaped, bag-shaped and column-shaped positive electrodes, and the shape of the positive electrode is adapted to the grid structure.

4. The flow battery of claim 1, wherein: the cathode material is a mixture or a compound of one or more of aluminum, vanadium, chromium, manganese, iron, cobalt, zinc, nickel, copper, titanium, graphite or a graphite composite material; the negative electrode is one or a combination of a plurality of sheet-shaped, net-shaped, film-shaped, rod-shaped, filiform, barrel-shaped, bag-shaped and columnar electrodes, and the shape of the negative electrode is adapted to the grid structure.

5. The flow battery of claim 1, wherein: one conductive cation in the electrolyte is a cation which can be inserted and extracted into and from the positive electrode, and comprises any one or more of lithium ions, sodium ions, zinc ions and magnesium ions; another is a mixture of cations including one or more of the ions of aluminum, vanadium, chromium, manganese, iron, cobalt, zinc, nickel, copper, titanium that can be deposited-dissolved on the negative electrode.

6. The flow battery of claim 1, wherein: the battery shell and the grid are made of high polymer materials, and comprise any one of polycarbonate, polyethylene, polypropylene, polyvinyl chloride, polymethyl methacrylate, polyamide, polylactic acid, polyurethane, polytetrafluoroethylene, polyphenylene sulfide, polyformaldehyde or polyphenylene oxide.

7. The flow battery of claim 1, wherein: one or more of glass fiber, plant fiber, synthetic fiber, asbestos, paper or porous ceramic can be filled between the pole pieces.

8. The flow battery of claim 1, wherein: the electrolyte also comprises one or a mixture of more of water-soluble starch, gelatin, cellulose, alginic acid, hyaluronic acid, chitosan, collagen, poly-L-lysine, poly-L-glutamic acid, polyacrylamide, polyoxyethylene, polyacrylate, polyvinyl alcohol, sodium carboxymethylcellulose, sodium silicate, sodium metasilicate, sodium polyacrylate, acetic acid, ammonium chloride, disodium hydrogen phosphate, sodium dihydrogen phosphate, sulfuric acid and citric acid.