KR102086386B1 - Metal fuel cell and metal fuel cell system using the same - Google Patents

Abstract

According to one or more exemplary embodiments, a metal fuel cell includes an anode electrode, which is a first tube structure having upper and lower portions open; A cathode electrode positioned in the first tube structure and extending along a length direction of the first tube structure; A separator disposed inside the first tube structure, the separator being a second tube structure having an open top and a closed bottom; Moss zinc pellets received inside the second tube structure; And an electrolyte supplied from an upper portion of the first tube structure and flowing to the lower portion of the first tube structure after contacting the first tube structure, the moss zinc pellet, and the cathode electrode. In this case, the separator prevents contact between the moss zinc pellets and the anode electrode.

Description

Metal fuel cell and metal fuel system {METAL FUEL CELL AND METAL FUEL CELL SYSTEM USING THE SAME}

TECHNICAL FIELD The present invention relates to metal fuel cells and metal fuel systems, and more particularly, to metal fuel cells and metal fuel systems in which mossy zinc pellets are applied as negative electrode active materials.

In general, a metal fuel cell is also called a metal air battery, and refers to a battery in which a metal such as iron, zinc, magnesium, aluminum, etc. is applied as a cathode, and an air diffusion electrode such as an oxygen electrode is used as the anode. By applying oxygen in the air as the active material of the anode, it has the advantage of being light in weight, and the cathode material is expected to realize high energy because of the relatively safe and cheap metal applied.

Among these, a system using a zinc fuel cell, which uses zinc as a fuel, is expected to be used as a generator and a power storage device because energy can be recycled, ie, charged and discharged, and recovered by oxidation and reduction of metal fuel. . The zinc fuel used in the zinc fuel cell has various forms such as plates, beads, powders, and electroplating.

The biggest problem with zinc used as fuel is the passivation by surface oxidation. The higher current density or zinc concentration in electrolyte, the worse this phenomenon is.If the non-conductor surface is formed, there is a disadvantage that the fuel utilization rate is lowered because no further discharge is made. There is this.

In order to overcome these disadvantages, a fluidized bed structure, a fixed bed structure, a proposal of electrolytic core circulation flow structure, and various technologies in such a structure have emerged, and the research of the related technology continues.

SUMMARY OF THE INVENTION An object of the present invention is to propose a structure and method for suppressing insulatorization of a negative electrode active material and obtaining high discharge efficiency in a metal fuel cell.

The problem to be solved by the present invention is to provide a metal fuel cell system having a metal fuel cell capable of obtaining the above-described high discharge efficiency.

The problem to be solved by the present invention is to propose a method for regeneration and recycling of the negative electrode active material and the electrolyte of the metal fuel cell.

A metal fuel cell according to one aspect is disclosed. The metal fuel cell may include an anode electrode, which is a first tube structure having upper and lower portions open; A cathode electrode positioned in the first tube structure and extending along a length direction of the first tube structure; A separator disposed inside the first tube structure, the separator being a second tube structure having an open top and a closed bottom; Moss zinc pellets received inside the second tube structure; And an electrolyte supplied from an upper portion of the first tube structure and flowing to the lower portion of the first tube structure after contacting the first tube structure, the moss zinc pellet, and the cathode electrode. In this case, the separator prevents contact between the moss zinc pellets and the anode electrode.

In an embodiment, the metal fuel cell may include a filter disposed under the first tube structure to filter the electrolyte solution; And an electrolyte container disposed under the filter to collect the filtered electrolyte solution.

In another embodiment, the supply speed of the electrolyte to the first tube structure may be controlled slowly so that the electrolyte flowing into the electrolyte container falls into the state of droplets.

In another embodiment, the moss zinc pellets may have a size of 1 to 10 mm, and may be a molded body of moss zinc electrolytically extracted from an electrolyte solution including a zincate.

In another embodiment, the moss zinc pellets may have an apparent density ratio of 60% to 90%.

In another embodiment, the separation membrane may pass through the electrolyte, and the moss zinc pellet may perform a function of preventing passage.

In another embodiment, the metal fuel cell, the upper insulator tube, a portion of which is inserted into and fixed between the first tube structure and the second tube structure on top of the first tube structure; And a lower insulator tube under the first tube structure, a portion of which is inserted and fixedly disposed between the first tube structure and the second tube structure.

In another embodiment, the metal fuel cell may further include a positive electrode terminal disposed on an outer circumferential surface of the first tube structure.

In another embodiment, the metal fuel cell, the electrolyte injection tube is introduced into the upper insulator tube disposed; And an electrolyte overflow discharge pipe disposed on the sidewall of the upper insulator tube.

In another embodiment, the lower insulator tube may include a filter for filtering the electrolyte solution and flowing downward; And a partition wall disposed below the filler and having an opening through which the filtered electrolyte solution passes.

Meanwhile, a metal fuel cell system according to another aspect is disclosed. The metal fuel cell system includes a metal fuel cell comprising moss zinc pellets as a negative electrode active material, and an electrolyte flowing in contact with the moss zinc pellets; An electrolysis extraction cell which electrolysis decomposes an electrolyte containing zincate, which is discharged from the metal fuel cell, to produce moss zinc; And a pellet manufacturing unit for agglomerating the produced moss zinc to produce the moss zinc pellets.

In one embodiment, the metal fuel cell, an anode electrode which is a first tube structure having an upper and lower portions open; A cathode electrode positioned in an inner center of the first tube structure and extending along a length direction of the first tube structure; And a separator disposed inside the first tube structure, the separator being a second tube structure having an open top and a closed bottom, wherein the moss zinc pellet is housed inside the second tube structure. The electrolyte may be supplied from an upper portion of the first tube structure to contact the first tube structure, the moss zinc pellet, and the cathode electrode, and then flow down to the lower portion of the first tube structure.

In another embodiment, the electrolytic extraction cell may be driven at a cell current density of 0.1 to 0.5 kA / m ² and a cell voltage of 1.9 to 2.5V for an electrolyte having a zinc concentration of 0.3 to 1.0 mol / L. have.

In another embodiment, the prepared moss zinc is a population of zinc in the form of moss having a size of 100 nm or less, and may have an apparent density ratio of 10% to 20%.

In another embodiment, the pellet manufacturing unit may agglomerate the lichen zinc by applying a pressure of 0.1 to 1 kg / cm ² to the lichen zinc.

In another embodiment, the moss zinc pellets are shaped bodies having a size of 1 to 10 mm, and may have an apparent density ratio of 60% to 90%.

In another embodiment, the electrolyte solution in which the zinc concentration is reduced by extracting the moss zinc from the electrolytic extraction cell may be provided to the zinc fuel cell and recycled.

According to one embodiment of the present invention, moss zinc pellets are applied as a negative electrode active material. The moss zinc pellets have a relatively low density compared to conventional active material materials such as zinc beads or zinc powder, and are excellent in reactivity while suppressing insulatorization (passivation) on the surface. As a result, the moss zinc pellets may exhibit a high output compared to materials such as zinc beads or zinc powder.

The moss zinc pellet is produced by collecting the moss zinc from the electrolyte discharged from the metal fuel cell and agglomerating the moss zinc. In this way, by collecting the moss zinc from the discharged electrolyte, it is possible to regenerate the electrolyte solution having a low zinc concentration from the discharged electrolyte. The regenerated electrolyte may be reinserted into the metal fuel cell.

According to an embodiment of the present invention, a metal fuel cell for discharging using the moss zinc pellets, an electrolytic extraction cell for producing the moss zinc, and a pellet manufacturing unit for producing the moss zinc pellets by agglomerating the moss zinc A metal fuel cell system can be provided. As described above, the metal fuel system has the advantage of being able to continuously apply high-power discharge and moss zinc pellets that can be easily regenerated and circulated as an electrode active material.

1 is a block diagram schematically illustrating a metal fuel cell system according to an embodiment of the present invention.
2 is a schematic diagram schematically showing a metal fuel cell system according to an embodiment of the present invention.
3 is a cross-sectional view schematically showing a metal fuel cell according to one embodiment of the present invention.
4 is a cutaway perspective view illustrating a lower portion of the metal fuel cell of FIG. 3.
5 is a perspective view schematically showing an assembly of a metal fuel cell according to an embodiment of the present invention.
6 is a graph showing a discharge test result of a metal fuel cell according to an embodiment of the present invention.
7 is a graph showing a discharge experiment result in the constant current mode of a metal fuel cell according to a comparative example of the present invention.
8 and 9 are photographs observed after the discharge test of the negative electrode active material according to an embodiment of the present invention.
10 and 11 are photographs observed after the discharge test of the negative electrode active material according to a comparative example of the present invention.
12 is a photograph showing a lichen zinc manufacturing process according to an embodiment of the present invention.
13 and 14 are photographs showing moss zinc produced through the lichen zinc production process according to an embodiment of the present invention.
15 is a photograph showing moss zinc pellets manufactured through a moss zinc pellet manufacturing process according to an embodiment of the present invention.

Hereinafter, exemplary embodiments will be described in more detail with reference to the accompanying drawings. In the drawings, the width, thickness, etc. of the components are enlarged in order to clearly express the components of each device. When described in the drawings as a whole, at the point of view of the observer, when one element is referred to as being positioned on top of another, this means that one element may be placed directly on top of another or that additional elements may be interposed between them. Include.

Like reference numerals in the drawings indicate substantially the same elements as each other. In addition, singular expressions should be understood to include plural expressions unless the context clearly indicates otherwise, and terms such as 'comprise' or 'have' include the features, numbers, steps, operations, components, and parts described. Or combinations thereof, it is to be understood that they do not preclude the presence or addition of one or more other features or numbers, steps, operations, components, parts or combinations thereof.

As mentioned above, metal fuel cells can be broadly classified into fluidized beds and fixed beds. First, looking at the fluidized bed, Denis Doniat et al. Proposed a fluidized bed zinc fuel cell in US Patent No. 3,887,400. As a floating size, a suspension containing zinc particles having a size of 20 to 30 µm was used, in which an electrolyte was circulated from below to collect current to prevent surface decontamination of the zinc metal particles. The electrochemical reaction was maintained by contacting the flowing zinc particles to the nickel goose cathode.

John Rayner Backhurst et al. Proposed a shape in which U. S. Patent No. 3,879, 225 pushes a metal fuel slurry through a horizontal slot at the bottom of the cell and floats in the cell to contact the cathode mesh.

Frank Solomon, in US Patent 4,147, 839, proposed another fluidized bed zinc fuel cell, in which zinc particles were injected at the top of the cell and flown using a stirrer in the cell to allow zinc particles to contact the cathode. Had

On the other hand, in the fluidized bed, the electrolyte is injected into the bottom of the cell to make the metal zinc particles float and the top is injected and then floated using a stirrer. There is a disadvantage in that it takes a lot of ancillary energy to use a high output because the lack of contact of the particles to the electrode.

In the case of powder, since the average size of the particles is small, it is advantageous to inject in the form of a fluid gel rather than the case of the powder itself. Jeffrey A. Colburn et al., In US Pat. No. 6,911,274, discloses a method of storing powdered metal zinc fuel and electrolyte together in a storage container and then supplying each cell using a pump. However, circulating the particles themselves puts a lot of load on the circulation system and there is a risk of clogging the pipe.

In addition, the fluidized bed requires continuous circulation or agitation of the electrolyte, but it is difficult to avoid frequent failures due to mechanical wear and complicated mechanisms.

On the other hand, in addition to the fluidized bed-type metal fuel cell, the development of the fixed bed form was also made. The fixed bed circulates the electrolyte in a cell filled with metal fuel. The burden on energy and auxiliary devices needed for circulation was much reduced and the size of the cells could be reduced.

The metal fuel filled in the fixed bed must be mechanically robust and appropriately sized so as not to be floated by the flow of the electrolyte, and thus, it is not free from passivation. One commonly used form is to circulate electrolyte in beads or pellet-filled cells. Zinc beads with a diameter of 1-5 mm can easily move into the cell, and after being filled in the cell, the electrolyte is continually consumed and discharged as the electrolyte circulates.

The zinc beads used here are manufactured in the process of melting and cooling the metal zinc and have dense molten surfaces. Therefore, when the activity of the electrolyte decreases, surface oxidation occurs and the electrical contact between the beads becomes poor. In other words, zinc metal in the bead often ends up in an unconsumed state, and thus a low discharge depth may occur frequently.

John F. Cooper proposed a cell inclined to narrow the lower portion of the US Patent 5,434,020 filled with 0.1 to 5 mm of zinc particles. As the discharge proceeds, the zinc particles become smaller in size, so they are designed to have a cell gap that is appropriate for the size of the particles at the bottom of the cell. The electrolyte enters the bottom of the cell and exits through the top, but vice versa.

Jeffrey A. Colburn et al. Proposed a refillable form in U.S. Patent No. 5,952,117, which was taken up from a storage container with metal zinc particles and electrolyte and supplied to the cell from above and separated from the cell when it was exhausted. It is. The technology allows the spent fuel to be separated from the cell system and reused in conjunction with the zinc regeneration unit.

Filling zinc particles or pellets in the cell with too high a density may not only disturb the flow of the electrolyte, but also cause the destruction of the cell due to excessive weight of the pellets. have. In particular, a power source that moves like an electric vehicle can be more problematic. Therefore, there is a need to use an improved material to lower the packing density and to achieve good electrical contact between the particles, thereby keeping the internal resistance low.

In addition, in the case where the decontamination of the zinc particles therein becomes severe, the output decreases and the fuel utilization decreases. Conversely, unlike fixed beds, fluidized beds can reduce this much because they keep small particles moving continuously. However, this situation is difficult to avoid because the zinc particles do not move in the fixed bed. In particular, in the cell into which the independent particles, ie, powder, pellets, or beads, may lose electric conduction ability between the particles, the discharge characteristics of the particles may be deteriorated.

On the other hand, the electrolyte circulation type applied in the fluidized bed or fixed bed may have the following conventional problems. In other words, the electrolyte circulation type requires a large amount of electrolyte to sufficiently dissolve the zinc ate, which leads to an increase in cost, weight, and volume, and thus, commercialization may be a problem.

In addition, if the metal fuel cell only performs a discharge operation, zinc hydroxide precipitates due to accumulated zinc ions, which may cause a disruption of the circulation system. Therefore, it is necessary to lower the zinc concentration of electrolyte for rational electrolyte management. As an example, there is a method of lowering the concentration of zinc ions in KOH electrolyte by adding calcium hydroxide, and precipitated in the form of calcium zincate (calcium zincate CaZn (OH) ₄ * 2H ₂ O). Aaron L. Zhu et al. “Increasing the electrolyte capacity of Alkaline Zn-Air Fuel Cells by Scavenging Zincate with Ca (OH) 2”, Chem Electorchem DOI: 10.1002 / celc.201402251, 2014, and is also published in US 2010/0196768 A1. . As such, although the reactivity of the electrolyte can be maintained high, this method has an important disadvantage that zinc cannot be recycled immediately.

In addition, another important problem of the electrolyte circulation type is the increase in internal pressure along the height of the cell. When the cell is filled with electrolyte, the pressure of the electrolyte increases as it goes to the lower part of the cell, and when used for a long time, leakage of the electrolyte at the air anode and accumulation of precipitates in the air anode are caused. Therefore, there is a need for a method that can alleviate this internal pressure.

On the other hand, in the case of a fixed bed, since it is a condition that can maintain the electrolyte solution in the wet state, it is determined that the required output can be achieved without completely filling the electrolyte solution. That is, the electrolyte is wet in the form of a neck at the point of contact between the particles. It may contain a larger amount of electrolyte than in the case of particles which are particularly small and have a large specific surface area. Therefore, this situation can be maintained only by spraying the electrolyte from the top of the cell, which can be maintained at a low internal pressure because it does not need to fill the electrolyte.

In the embodiment of the present invention described below, the fixed fuel cell and the electrolyte circulating structure is adopted, a metal fuel cell applying moss zinc pellets that can be easily regenerated and circulated while being capable of high output discharge by suppressing insulator formation. And a metal fuel cell system.

1 is a block diagram schematically illustrating a metal fuel cell system according to an embodiment of the present invention. 2 is a schematic diagram schematically showing a metal fuel cell system according to an embodiment of the present invention.

Referring to FIG. 1, the metal fuel cell system 1 includes a metal fuel cell 10, an electrolytic extraction cell 20, a pellet manufacturing unit 30, and an external power source 40.

The metal fuel cell 10 may apply moss zinc pellets as a negative electrode active material. At this time, in the present specification, the 'moss zinc pellet' has a size of about 1 to 10 mm, and refers to an aggregate of moss zinc formed from moss zinc electrolytically extracted from an electrolyte solution including zincate, which will be described later. Can be. At this time, the moss zinc pellets may have an apparent density ratio of 60% to 90%. The apparent density ratio of this value may be due to the fact that the moss zinc pellet has a porous structure.

More specifically, referring to FIG. 2, the metal fuel cell 10 may include an anode electrode 110, which is an air electrode, and a cathode electrode 120 spaced apart from the anode electrode 110. For example, the metal fuel cell 10 may include an aqueous solution containing potassium hydroxide (KOH) as the electrolyte 162. After the electrolyte 162 flows into the upper portion of the metal fuel cell 10, the electrolyte 162 passes through the metal fuel cell 10 in a downward direction and participates in a discharge reaction. The discharged electrolyte 164 passes through the lower insulator tube 150 on which the filter 152 is disposed and is discharged into the electrolyte container 160.

Meanwhile, the moss zinc pellet 140 may be accommodated in the separator 130 having a tube shape disposed between the anode electrode 110 and the cathode electrode 120. As shown in FIG. 2, the anode electrode 110 may have a form of a tube structure in which upper and lower portions are open. The cathode electrode 120 is located inside the tube structure and may have a rod shape or a tube structure shape. Since the separator 130 is spaced apart from the anode electrode 110, the moss zinc pellet 140 may be in direct contact with the anode electrode 110 to prevent an electrical short circuit.

The moss zinc pellet 140 may emit electrons while being oxidized in the electrolyte 162. The electrons may be delivered to the cathode electrode 120 via the plurality of moss zinc pellets 140. In this case, the reaction in which the moss zinc pellet emits electrons and the reaction in which the emitted electrons reach the cathode electrode 120 may be referred to as a cathode reaction. The cathode electrode 120 is connected to the anode electrode 110 by an external conductor (not shown), so that the electrons reaching the cathode electrode 120 may move to the cathode electrode 110.

The anode electrode 110 may proceed with an anode reaction that generates hydroxide ions (OH−) by using oxygen absorbed in air, electrons moved from the cathode electrode 120, and water in the electrolyte 162.

Through the cathode reaction and the anode reaction, the discharge operation of the metal fuel cell 10 may proceed. While the discharge operation is in progress, the zincate generated as a by-product of the cathode reaction may be dissolved in the electrolyte 162. The zincate may refer to a salt in which zinc oxide or zinc hydroxide produced as a by-product of the cathode reaction is dissolved in an electrolyte.

The electrolyte 162 in which the zincate is generated through the discharging operation may be accommodated in the electrolyte container 160 after passing through the filter 152 positioned under the metal fuel cell 10. The electrolyte having the high concentration of the contained zincate is delivered to the electrolytic extraction cell 20.

1 and 2, the electrolytic extraction cell 20 may electrolyze an electrolyte solution discharged from the metal fuel cell 10 to extract moss zinc from the ginkgo. Power required for the electrolytic extraction may be supplied from an external power source (40).

The moss zinc may include, for example, primary particles having a size (diameter) of 100 nm or less. The lichen zinc is a cluster of zinc having a mossy form, and may have an apparent density ratio of about 10% to 20%. The moss zinc may be delivered to the pellet manufacturing unit 30.

In one embodiment, the step of extracting moss zinc, the cell current density of 0.1 to 0.5 kA / m ² and cell voltage conditions of 1.9 to 2.5V for an electrolyte having a zinc concentration of 0.3 to 1.0 mol / L It may proceed to the condition driven in. If the current density is higher than 0.5 kA / m ² , the particle size increases and zinc particles having metallic luster, rather than moss zinc, may be formed. In addition, when the zinc concentration is lower than 1.0 mol / L, particles such as dendrites may be formed rather than moss zinc.

1 and 2, the pellet manufacturing unit 30 aggregates moss zinc extracted from the electrolytic extraction cell 20 to produce moss zinc pellets. The moss zinc pellet may be a chipped body of moss zinc, which is generated by applying an appropriate stress to the low apparent density ratio moss zinc clusters generated in the electrolytic extraction cell 20. As an example, the method of applying the stress may include pressing in a vertical direction, roll pressing using a roller, extrusion, or the like. The pellet manufacturing unit 30 may receive power from the external power source 40 for the aggregation of the moss zinc.

In one embodiment, the pellet manufacturing unit 30 may agglomerate the lichen zinc by applying a pressure of 0.1 to 1 kg / cm ² to the lichen zinc. The moss zinc pellets may have an apparent density ratio of about 60% to 90%. The moss zinc pellets may be prepared by cutting to have a size of about 1 to 10 mm.

The molded moss zinc pellets can be recycled as a negative electrode active material. As shown in FIG. 2, the molded moss zinc pellet may be re-injected to be accommodated in the separator 130 inside the metal fuel cell 10.

Referring to FIGS. 1 and 2, after the moss zinc is extracted from the electrolytic extraction cell 20, the electrolyte solution in which the low concentration of zinc is dissolved passes through the filter unit 50, and then the metal is pumped by the pump 60. The fuel cell 10 may be resupply inside.

As described above, the electrolyte solution and the moss zinc pellets may be discharged from the metal fuel cell 10 after participating in the discharge reaction in the metal fuel cell 10, and after being converted into an electrolyte solution containing a high concentration of zincate. The discharged electrolyte may be recycled through the electrolytic extraction cell 20 and the pellet maker 30 and then re-supplied into the metal fuel cell 10 to be recycled.

3 is a cross-sectional view schematically showing a metal fuel cell according to one embodiment of the present invention. 4 is a cutaway perspective view illustrating a lower portion of the metal fuel cell of FIG. 3.

3 and 4, the metal fuel cell 10 includes a positive electrode 110, a negative electrode 120, and a separator 130. In addition, the metal fuel cell 10 includes an upper insulator tube 140 positioned above the anode electrode 110, and a lower insulator tube 150 positioned below the anode electrode 110.

Although not shown in FIGS. 3 and 4, moss zinc pellets as a negative electrode active material may be accommodated in the separator 130. The separator 130 may suppress direct contact between the moss zinc pellet and the anode electrode 110.

Also, although not shown in FIGS. 3 and 4, the electrolyte may be supplied into the upper insulator tube 140 through the electrolyte injection tube 172. The electrolyte may contact the cathode electrode 120, the anode electrode 110, and the moss zinc pellet to participate in the metal fuel cell reaction, and then be discharged to the lower portion of the anode electrode 110.

The anode electrode 110 may be a first tube structure 110 having upper and lower portions open. The anode electrode 110 may function as an air anode. For example, the anode electrode 110 may be a material in which carbon, a hydrophobic polymer, a fluororesin, and a catalyst are combined. The positive electrode 110 may include an upper terminal portion 115 and a lower terminal portion 117. The upper terminal unit 115 and the lower terminal unit 117 may be connected to the cathode electrode 120 through a conductive line (not shown). The terminal unit 115 and the lower terminal unit 117 may be made of a conductive material. For example, the terminal unit 115 and the lower terminal unit 117 may be made of stainless steel.

The anode electrode 110 uses an oxygen absorbed in the air, electrons moved from the cathode electrode 120 through the conductive wire, and water in the electrolyte to react with the anode to generate hydroxide ions (OH-) in the electrolyte. You can proceed.

The cathode electrode 120 may be positioned inside the first tube structure 110 and extend along the length of the first tube structure 110. The cathode electrode 120 may have a tube structure shape or a rod shape. For example, the cathode electrode 120 may be formed of brass, phosphor bronze, iron, nickel, silver, iron, or the like. The cathode electrode 120 may collect electrons generated while the moss zinc pellet is oxidized in an electrolyte. Electrons collected by the cathode electrode 120 may move to the terminal portions 115 and 117 of the anode electrode 110 through an external conductor (not shown). Meanwhile, a reaction in which the moss zinc pellet emits electrons and a reaction in which the emitted electrons are collected on the cathode electrode 120 may be referred to as a cathode reaction.

3 and 4, the separator 130 may be disposed inside the first tube structure 110, and may be a second tube structure 130 having an open top and a closed bottom. The separator 130 may be, for example, a hydrophilic porous film. The separator 130 may include an alkali resistant polymer material. The separator 130 may be made of, for example, a material such as polyvinyl alcohol (PVA), polypropylene (PP), polyethylene (PE), or the like.

The separator 130 may pass the electrolyte and prevent the moss zinc pellet from passing through. Thus, the moss zinc pellet may be accommodated in the second tube structure 130. Since the second tube structure 130 is spaced apart from the first tube structure 110, the separator 130 may prevent the moss zinc pellet and the anode electrode 110 from directly contacting each other.

Referring to FIG. 3, the upper insulator tube 140 may be fitted between the first tube structure 110 and the second tube structure 130. Specifically, a portion of the upper insulator tube 140 may be inserted into and fixed to the first tube structure 110. The upper insulator tube 140 may be made of, for example, an FRP material.

In this case, the upper terminal 115 may be disposed to surround the outer circumferential surface of the first tube structure 110 to which the upper insulator tube 140 is fitted. The upper terminal portion 115 may help the upper insulator tube 140 to be fixedly coupled to the first tube structure 110.

Referring to FIG. 3, an electrolyte injection tube 172 may be disposed inside the upper insulator tube 140. In addition, an electrolyte overflow discharge pipe 182 may be disposed on a sidewall of the upper insulator tube 140. The electrolyte overflow discharge pipe 182 may be installed to temporarily prevent the electrolyte from overflowing in the metal fuel cell 10 when the electrolyte is supplied into the metal fuel cell 10. The electrolyte overflow discharge pipe 182 may be disposed at an appropriate height of the upper insulator tube 140 to discharge the electrolyte inside the upper insulator tube 140 to the outside.

3 and 4, the lower insulator tube 150 may be fitted between the first tube structure 110 and the second tube structure 130. In detail, a portion of the lower insulator tube 150 may be inserted into and fixed to the inside of the first tube structure 110. The lower insulator tube 150 may be made of, for example, an FRP material.

In this case, the lower terminal portion 117 may be disposed to surround the outer circumferential surface of the first tube structure 110 to which the lower insulator tube 150 is fitted. The lower terminal portion 117 may help the lower insulator tube 150 to be fixedly coupled to the first tube structure 110.

The lower insulator tube 150 may include a filter 152 for filtering the electrolyte to flow downward. The filter 152 may be made of, for example, a PP nonwoven fabric. The filter 152 may be installed to cover the inside of the lower insulator tube 150 at the bottom of the first tube structure 110.

In addition, the lower insulator tube 150 may include a partition wall 154 disposed under the filter 152 and having an opening 156 through which the filtered electrolyte solution passes. The partition wall 154 may be made of, for example, an FRP material. The partition wall 154 may be installed to cover the inside of the lower insulator tube 150.

The electrolyte passing through the opening 156 of the partition 154 may be discharged to the outside of the lower insulator tube 150 through the outlet 158.

As described above, in the metal fuel cell 10 according to the exemplary embodiment of the present invention, the discharge operation of the battery may proceed through the positive reaction and the negative reaction. During the discharging operation, the zincate produced as a byproduct of the cathode reaction is dissolved in the electrolyte.

The electrolyte in which the zincate generated through the discharging operation is dissolved may be discharged to the outside after being filtered through the filter 152 positioned under the metal fuel cell 10.

5 is a perspective view schematically showing an assembly of a metal fuel cell according to an embodiment of the present invention. Referring to FIG. 5, a plurality of metal fuel cells 10 may be seated in a slot (not shown) installed in the electrolyte container 160. The cathode electrode 120 of one metal fuel cell 10 and the anode electrode 110 of another neighboring metal fuel cell 10 are connected to each other through an external conductor (not shown), thereby providing a plurality of metal fuel cells 10. ) May be electrically connected in series. As such, by increasing the number of slots, the number of metal fuel cells 10 to be seated in the slots may be increased.

The electrolyte injection tubes 172 of the metal fuel cells 10 may be connected to one electrolyte injection collection tube 170. In addition, the electrolyte overflow discharge pipes 182 of the metal fuel cells 10 may be connected to one electrolyte discharge collection pipe 180.

In one embodiment, the plurality of metal fuel cells 10 may share one electrolyte container 160. At this time, the supply rate of the electrolyte solution to the metal fuel cell 10 may be sufficiently slowed so that the electrolyte solution 164 passing through the metal fuel cell 10 may fall into the electrolyte container 160 in the form of droplets. Accordingly, by inhibiting the electrolyte 164 falling through the plurality of metal fuel cells 10 from forming a continuous flow, the metal fuel cells 10 are electrically connected to each other through the electrolyte contained in the electrolyte container 160. Can be suppressed. As a result, it is possible to suppress the occurrence of an electric leakage loss for each metal fuel cell 10 at the time of battery reaction occurring in the metal fuel cells 10.

In addition, the rate of supply of the electrolyte solution is sufficiently slowed to prevent the application of excessive pressure to the metal fuel cell 10 while passing through the inside of the metal fuel cell 10. As a result, the output of the metal fuel cell 10 can be prevented from being reduced or leaked. In addition, the metal fuel cell 10 may be continuously operated by rapidly transferring the electrolyte solution 164 to the electrolyte extraction cell before a large amount of electrolyte solution 164 collects in the electrolyte container 160.

Hereinafter, embodiments of the present invention will be described in detail through specific experimental examples.

Example  -Metal Fuel Cell Fabrication

An air anode electrode, a tube structure having a diameter of 34 mm and a length of 100 mm, was made, and 10 mm of upper insulator tubes and lower insulator tubes of 32 mm diameter FRP material were inserted at both ends. Subsequently, an upper terminal portion and a lower terminal portion made of stainless steel were provided on the air anode electrode. The lower insulator tube was provided with a partition wall made of FRP plate. On the partition, the filter which consists of PP nonwoven fabric was arrange | positioned. The separator was wound around the tube structure of the anode electrode.

Then, zinc fuel was filled into the separator. The amount of zinc fuel was filled in to fill the effective 80 mm length of the positive electrode. As the zinc fuel, as Comparative Example 1, 300g of zinc in the form of a bead having a diameter of 3 mm was provided, and as Comparative Example 2, 300g of zinc powder having a size of 100 μm applied to an alkaline battery was provided. As Example 1, 50 g of lichen zinc pellets were provided, and as Example 2, 60 g of lichen zinc pellets were provided. At this time, the moss zinc refers to the zinc extract before the electrolytic extraction from the electrolyte solution to be molded into the moss zinc pellet of Example 1. In addition, a brass tube having a diameter of 4 mm was installed at the center of the tube structure of the anode electrode as the cathode electrode.

Example  -Lichen Zinc Production

Lithium zinc was prepared by electrolytic extraction of an electrolyte solution containing a zincate using an external power source. Electrolytic extraction was performed in a constant current mode using a DC power supply.

An aqueous solution of 35% to 45% KOH was applied as an electrolyte, but discharged after performing a discharge operation in a zinc fuel cell. At this time, the electrolyte solution is a solution to maintain the ZnO concentration 1.0 mol / L or less. The electrolytic extraction cell was a brass plate for the cathode and a stainless steel mesh for the anode. The distance between two opposing electrodes was 5 cm. Fine oxygen bubbles were generated at the anode, and moss zinc was formed at the cathode, which vibrated to prevent the short-circuit between the electrodes. Initially, the electrodeposition plating layer was visible and continued electrolysis, forming only black particles.

The electrolytic extraction produced at a current density of 0.1-0.5 kA / m2. At this time, the inter-cell voltage was maintained at 1.9 to 2.5V.

When the produced moss zinc was put on a plate and pressed by applying a pressure of 0.1 to 1 kg / cm ² , the electrolyte solution went out to the surroundings, and moss zinc was agglomerated. This was cut to a size of 5 mm or less to make pellets.

Experimental Example  -Discharge test

In the metal fuel cell prepared in Example, a discharge experiment was conducted by applying the negative electrode active materials of Comparative Example 1, Comparative Example 2, Example 1 and Example 2.

As described above, Comparative Example 1 was applied as a negative electrode active material, zinc in the form of beads having a diameter of 3mm, and Comparative Example 2 was applied to 100 μm zinc powder. In contrast, Example 1 applied moss zinc pellets as a negative electrode active material, and Example 2 applied moss zinc.

Review

6 is a graph showing a discharge test result of a metal fuel cell according to an embodiment of the present invention. More specifically, FIG. 6 shows the results of the discharge experiment using the moss zinc pellets of Example 1 as the negative electrode active material (610 graphs) and the discharge experiment results using the moss zinc of Example 2 as the negative electrode active material (620 graphs). It is shown through the voltage curve.

Referring to FIG. 6, it can be seen that the output of the graph 610 of the first embodiment is higher than that of the second embodiment 620. Specifically, in the case of Example 1, it can be seen that a current of 9A or more occurred.

7 is a graph showing a discharge experiment result in the constant current mode of a metal fuel cell according to a comparative example of the present invention. More specifically, FIG. 7 shows current-discharge test results (610 graphs) in which the moss zinc pellets of Example 1 were applied as the negative electrode active material and discharge test results (620 graphs) in which the moss zinc of Example 2 was applied as the negative electrode active material. It is shown through the voltage curve.

Referring to FIG. 7, in the case of Example 1, a relatively high output was generated even in the '9A application test', and a relatively high depth of discharge (DOD) was shown. In Example 2, the output of the "3A application test" level is shown. On the other hand, while the test in the constant current mode at 9A or 3A at the beginning of the discharge, the test was continued by switching the discharge current to 1A as the voltage of the cell was lowered. At this time, the fuel utilization rate (or discharge depth) of Example 1 and Example 2 was discriminated by 68% and 34%, respectively.

8 and 9 are photographs observed after the discharge test of the negative electrode active material according to an embodiment of the present invention. 8 has shown the shape of the moss zinc pellet of Example 1, and FIG. 9 has shown the shape of the moss zinc of Example 2. FIG.

8 and 9, in the case of Example 2 of FIG. 9, it can be seen that zinc by-products are dispersed in a relatively bright color, which indicates that the moss zinc powder has been oxidized. On the other hand, it can be seen that the moss zinc pellet of Example 1 maintains a high activity surface.

On the other hand, in the discharge test results, in the case of Comparative Examples 1 and 2, a current of 5 A was output, respectively, and the output was lower than in the case of Example 1. The fuel utilization rates of Comparative Examples 1 and 2 were all 20% or less, and the outputs were all finished at about 40 to 50 Ah. At this time, the state of the negative electrode active material of Comparative Examples 1 and 2 in which the discharge test was completed was observed.

10 and 11 are photographs observed after the discharge test of the negative electrode active material according to a comparative example of the present invention. Referring to FIG. 10, in Comparative Example 1, a nonconducted mass was observed with the surface oxidized. Referring to FIG. 11, in the case of comparison 2, it was observed that the powder particles agglomerated and cemented.

12 is a photograph showing a lichen zinc production process according to an embodiment of the present invention. Referring to FIG. 12, it is possible to observe moss zinc formed at the cathode in the constant current mode. Moss zinc is produced through electrolytic extraction in transparent PVC cells.

13 and 14 are photographs showing moss zinc produced through the lichen zinc production process according to an embodiment of the present invention. As above-mentioned, the moss zinc produced | generated by electrolytic extraction of the electrolyte solution containing a jincate was observed. The moss zinc can confirm the shape of the cluster consisting of primary particles having a size of 100 nm or less.

15 is a photograph showing moss zinc pellets manufactured through a moss zinc pellet manufacturing process according to an embodiment of the present invention. A pressure of 0.1 to 1 kg / cm ² was applied to the moss zinc produced through electrolytic extraction, thereby producing agglomerates of moss zinc with relatively improved apparent density ratios. Then, by cutting the aggregate of such moss zinc to a size of 5 mm, moss zinc pellets as shown can be produced.

As described above, according to the embodiment of the present invention, lichen zinc pellet may be applied as the negative electrode active material. The moss zinc pellets have a relatively low density compared to conventional active material materials such as zinc beads or zinc powder, and are excellent in reactivity while suppressing insulatorization (passivation) on the surface. As a result, the moss zinc pellets may exhibit a high output compared to materials such as zinc beads or zinc powder.

The moss zinc pellet is produced by collecting the moss zinc from the electrolyte discharged from the metal fuel cell and agglomerating the moss zinc. In this way, by collecting the moss zinc from the discharged electrolyte, it is possible to regenerate the electrolyte solution having a low zinc concentration from the discharged electrolyte. The regenerated electrolyte may be recycled to the metal fuel cell and recycled.

According to an embodiment of the present invention, a metal fuel cell for discharging using the moss zinc pellet, an electrolytic extraction cell for producing the moss zinc, and a pellet manufacturing unit for agglomeration of the moss zinc to produce the moss zinc pellets A metal fuel cell system can be provided. As described above, the metal fuel system has the advantage of being able to continuously apply high-power discharge and moss zinc pellets that can be easily regenerated and circulated as an electrode active material.

Although described above with reference to the drawings and embodiments, those skilled in the art various modifications and embodiments disclosed in the present application within the scope not departing from the spirit of the present application described in the claims below It will be understood that it can be changed.

100: lichen zinc pellet, 110: anode electrode,
115: upper terminal portion, 117: lower terminal portion,
120: cathode electrode, 130: separator,
140: upper insulator tube, 150: lower insulator tube,
152: filter, 154: partition wall, 156: opening, 158: outlet,
160: electrolyte container, 162 & 164: electrolyte solution,
170: electrolyte injection tube, 172: electrolyte injection tube,
180: electrolyte discharge collection tube, 182: electrolyte overflow discharge tube.

Claims (19)

A plurality of metal fuel cells and an electrolyte container unique to the plurality of metal fuel cells,
Each of the plurality of metal fuel cells
An anode electrode which is a first tube structure having an upper and lower portions opened;
A cathode electrode positioned in the first tube structure and extending along a length direction of the first tube structure;
A separator disposed inside the first tube structure, the separator being a second tube structure having an open top and a closed bottom;
Moss zinc pellets received inside the second tube structure;
An electrolyte supplied from an upper portion of the first tube structure and flowing into a lower portion of the first tube structure after contacting the first tube structure, the moss zinc pellet, and the cathode electrode; And
A filter disposed below the first tube structure to filter the electrolyte;
The separator prevents contact between the moss zinc pellets and the anode electrode
The electrolyte container is disposed under the filter of the plurality of metal fuel cells to collect the filtered electrolyte solution,
The feed rate of the electrolyte to the first tube structure is controlled slowly so that the electrolyte flowing into the electrolyte container falls into the state of droplets.
Metal fuel cell assembly.
delete delete According to claim 1,
The moss zinc pellets
It has a size of 1 to 10 mm, and is a molded body of moss zinc extracted electrolytically from an electrolyte solution containing a zincate.
Metal fuel cell assembly.
According to claim 1,
The moss zinc pellets
Having an apparent density ratio of 60% to 90%
Metal fuel cell assembly.
According to claim 1,
The separator passes the electrolyte and the moss zinc pellets performs a function of preventing passage.
Metal fuel cell assembly.
According to claim 1,
An upper insulator tube, on a portion of the first tube structure, a portion of which is inserted and fixedly disposed between the first tube structure and the second tube structure; And
A lower insulator tube below the first tube structure, a portion of which is inserted and fixedly disposed between the first tube structure and the second tube structure;
Metal fuel cell assembly.
The method of claim 7, wherein
Further comprising a positive electrode terminal disposed on the outer circumferential surface of the first tube structure
Metal fuel cell assembly.
The method of claim 7, wherein
An electrolyte injection tube introduced into the upper insulator tube and disposed; And
Further comprising an electrolyte overflow discharge pipe disposed on the side wall of the upper insulator tube
Metal fuel cell assembly.
The method of claim 7, wherein
The lower insulator tube is
A filter for filtering the electrolyte to flow downward; And
A partition wall disposed below the filter, the partition having an opening through which the filtered electrolyte solution passes;
Metal fuel cell assembly.
A metal fuel cell assembly including moss zinc pellets as a negative electrode active material, and an electrolyte flowing in contact with the moss zinc pellets;
An electrolysis extraction cell which electrolysis decomposes an electrolyte containing zincate, which is discharged from the metal fuel cell, to produce moss zinc; And
A pellet manufacturing unit for agglomerating the produced moss zinc to produce the moss zinc pellets;
The metal fuel cell assembly is
A plurality of metal fuel cells and an electrolyte container shared by the plurality of metal fuel cells,
Each of the plurality of metal fuel cells
An anode electrode which is a first tube structure having an upper and lower portions opened;
A cathode electrode positioned in the first tube structure and extending along a length direction of the first tube structure;
A separator disposed inside the first tube structure, the separator being a second tube structure having an open top and a closed bottom;
Moss zinc pellets received inside the second tube structure;
An electrolyte solution supplied from an upper portion of the first tube structure and flowing into the lower portion of the first tube structure after contacting the first tube structure, the moss zinc pellet, and the cathode electrode; And
A filter disposed below the first tube structure to filter the electrolyte;
The separator prevents contact between the moss zinc pellets and the anode electrode,
The electrolyte container is disposed under the filter of the plurality of metal fuel cells to collect the filtered electrolyte solution,
The feed rate of the electrolyte to the first tube structure is controlled slowly so that the electrolyte flowing into the electrolyte container falls into the state of droplets.
Metal fuel cell system.
delete delete delete The method of claim 11, wherein
The electrolytic extraction cell
For electrolytes with zinc concentrations of 0.3 to 1.0 mol / L, they are driven at cell current densities of 0.1 to 0.5 kA / m ² and cell voltage conditions of 1.9 to 2.5V.
Metal fuel cell system.
The method of claim 11, wherein
Lichen zinc prepared above
A colony of mossy zinc with a size of 100 nm or less, with an apparent density ratio of 10% to 20%.
Metal fuel cell system.
The method of claim 11, wherein
The pellet manufacturing unit
Applying a pressure of 0.1 to 1 kg / cm ² to the lichen zinc, to aggregate the lichen zinc
Metal fuel cell system.
The method of claim 11, wherein
The moss zinc pellets
A molded article having a size of 1 to 10 mm, having an apparent density ratio of 60% to 90%
Metal fuel cell system.
The method of claim 11, wherein
The moss zinc is extracted from the electrolytic extraction cell and the electrolyte having a reduced zinc concentration is provided to the metal fuel cell and recycled.
Metal fuel cell system.

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