KR20170143098A - Air injectable zinc air secondary battery - Google Patents

Abstract

The present invention relates to an air injection-type zinc air secondary battery comprising: an electrolyte; a positive electrode; and a negative electrode including zinc; a metal filter installed, toward the positive electrode, a distance apart from the negative electrode, and having a space formed therein; and a separation membrane which is installed between the metal filter and the positive electrode. Before a zinc ion is educed to metal zinc in a charging process, a part thereof is reduced to the negative electrode by passing through the separation membrane and the metal filter. The other part thereof is produced as metal zinc in the space.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an air-injecting zinc-

The present invention relates to an air injection type zinc-air secondary battery.

Generally, air zinc secondary batteries have much higher energy densities than lithium ion batteries, but they are not yet commercialized due to their low capacity maintenance characteristics due to irreversibility of charging.

Zinc is already widely used as a negative electrode active material of a primary cell, but it is not used as an anode active material of a secondary battery. This is because, unlike the primary cell, zinc dendrite is formed on the surface of the zinc electrode during charging and discharging repeatedly in the secondary cell. In a battery using metal zinc as a cathode, zinc metal is dissolved in the solution as zinc ions during the discharging process, and dissolved zinc ions are precipitated again into metallic zinc. At this time, zinc precipitates in the form of dendritic crystals, and the zinc dendrite thus produced increases the irreversibility of charging and discharging reactions, resulting in deterioration of battery capacity and cycle life.

In addition, zinc dendrites grow in the anode direction. When the growth progresses much, the zinc dendrite penetrates the separator and contacts with the anode, thereby causing a serious problem of battery short circuit. In order to solve such problems, researches for alloying zinc with a dissimilar metal or adding an additive to an electrolyte have been conducted for a long period of time, but no method for completely inhibiting the production of zinc dendrite has been found yet.

However, the air zinc secondary battery is advantageous in that the discharge voltage is uniform, the storage characteristic is good, there is no pollutant-free environment-friendly, there is no problem in fuel compression and storage, and the manufacturing cost is low.

The operation principle of the air zinc secondary battery is to provide a zinc (Zn) metal as fuel, to provide air as an oxide, and to provide an alkaline aqueous solution as an electrolyte. Zinc transfers electrons to an anode current collector while forming a zinc cation (Zn ²⁺ ) in an aqueous alkaline solution, and the generated electrons move to a cathode current collector through an external circuit. In the cathode current collector, oxygen is reduced by a catalyst Hydroxide ions (OH <"& gt ^; ), and the hydroxide ions move in the direction of the negative electrode through the electrolytic solution by a concentration gradient. The hydroxide ions migrate to the anode current collector and react with the zinc cation to form the final product, zinc oxide, which is converted to electrical energy by the oxidation of zinc and the reduction of oxygen.

Korean Patent Laid-Open Publication No. 10-2014-0071964 discloses a zinc-air battery which is rechargeable and which exhibits a longer lifetime than zinc-air, comprising at least one zinc-containing structure, at least one oxygen- Providing a zinc-air precursor comprising one air electrode; Wherein the zinc-air cell comprises a first electrode pair during charging of the air cell, the electrode pair comprising the at least one zinc-containment structure and the at least one oxygen release structure; The zinc-air cell includes a second electrode pair for discharging the air cell, and the electrode pair includes the at least one zinc-containment structure and the at least one air electrode.

Korean Patent Registration No. 10-1574004 discloses a zinc-air secondary battery having an electrolyte storage portion for supplying an electrolyte solution lost during charging and discharging and an electrolyte battery cell to improve the service life of the battery. An air electrode including an air anode membrane, A negative electrode comprising a negative electrode active material including zinc (Zn) and a zinc negative electrode gel containing an aqueous caustic solution; and a separator interposed between the negative electrode and the negative electrode; An electrolyte storage part for storing a caustic aqueous solution of potassium, which is an electrolytic solution; And an electrolyte solution supply unit for supplying a cathodic aqueous solution from the electrolyte solution reservoir to the cathode and the cathode gel, wherein the concentration of the caustic solution is 6M or more, and the electrolyte solution reservoir has an inner layer containing nickel .

U.S. Patent No. 9,293,791 provides a zinc rechargeable battery capable of preventing a short circuit between an anode and a cathode due to zinc dendrite, comprising: a negative electrode including a positive electrode and including zinc; An electrolyte solution containing an alkacyl metal hydroxide; And a separator including an inorganic solid electrolyte body disposed between the positive and negative electrodes and separating the positive and negative electrodes from each other and having hydroxide ion conductivity.

Korean Patent Publication No. 10-2014-0071964 Korean Patent Registration No. 10-1574004 U.S. Patent No. 9,293,791

It is an object of the present invention to provide an air-injected zinc-air secondary battery with improved performance.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not intended to limit the invention to the particular embodiments that are described. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, There will be.

According to an aspect of the present invention, there is provided a zinc-air secondary battery comprising: an electrolytic solution; anode; And a separator provided between the metal filter and the anode, wherein the separator is disposed between the metal filter and the anode, the separator being disposed at a distance from the anode toward the anode to form a space, A part of the metal is passed through the separator and the metal filter to be reduced to the cathode before the zinc ion is precipitated into the metal zinc, and the remaining part is formed of metal zinc in the space.

More specifically, the separation membrane may be stacked on the metal filter and face the anode.

Air supplied from the outside of the zinc-air secondary battery can be injected into the anode.

And a housing having a corresponding opening toward the negative electrode, wherein the positive electrode is installed in an opening of the housing, and air supplied from the outside of the zinc-air secondary battery can be injected into the housing.

The electrolytic solution can circulate through the inside and outside of the zinc-air secondary battery.

And an air supply means having a nozzle for supplying air supplied from the outside of the zinc-air secondary battery to the electrolytic solution.

And micro bubble generating means having two metal members disposed at a distance from each other and generating micro bubbles in the electrolyte by supplying positive and negative electrodes of the power source to the metal members, respectively.

The electrolyte solution may be replenished from the outside of the zinc-air secondary battery.

And a charging auxiliary electrode provided adjacent to the anode.

According to the present invention, the zinc ions dissolved in the electrolytic solution during the discharging process pass through the separator and the metal filter before being precipitated into the metal zinc during the charging process, so that a part of the zinc ions is reduced to the cathode, Therefore, zinc dendrite is not generated in the electrolytic solution. Therefore, the zinc dendrite produced in the electrolyte increases the irreversibility of the charging and discharging reaction, thereby eliminating the existing problems that cause deterioration of the capacity and cycle life of the battery, so that the performance of the battery can be greatly improved and maintained for a long period of time.

Also, the viscosity of the electrolyte increases with the increase of ZnO due to the chemical reaction, and since such viscosity hinders the movement of the hydroxide ion, the higher the concentration, the more the performance of the battery is affected. In addition, not only the oxygen required for the reaction exists in the air used as the anode but also carbon dioxide which increases the viscosity is present, and carbon dioxide forms the carbonate in the electrolyte and increases the viscosity. As the viscosity of the electrolyte increases, the ionic conductivity is lowered by inhibiting the movement of the ions, thereby affecting the performance of the battery. In the present invention, air is injected into the electrolyte and microbubbles are generated, Performance can be greatly improved and maintained for a long time.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing an entire system of an air-injected zinc-air secondary battery of the present invention. FIG.
2 is a view showing an air-injected zinc-air secondary battery of the present invention.
3 is a view showing another example of the air-injected zinc-air secondary battery of the present invention.
4 is a view showing still another example of the air-injected zinc-air secondary battery of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same components are denoted by the same reference symbols whenever possible. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

1, the air-injected zinc-air secondary battery 100 of the present invention is configured such that air is introduced from a compressed air storage tank 11 for storing air compressed by the air compressor 10, The electrolytic solution is circulated through the electrolytic solution tank 35 through the circulating motor pump 33 provided in the middle of the electrolytic solution supply tank 31 and the electrolytic solution is replenished from the electrolyte replenishing tank 40. Microbubbles are generated in the electrolytic solution, Is supplied from the power supply means (50). For example, the power supply means 50 may be charged with a power obtained from solar power generation or a commercial power supply, and may be supplied to a battery or the like.

2, the air-injected zinc-air secondary battery 100 of the present invention includes a battery case 101 having a sealed space therein. Inside the battery case 101, an electrolyte 103 It is filled. The battery case 101 can be closed by opening and closing the upper portion.

The electrolytic solution 103 may be either aqueous or oily, and may be either neutral or alkaline, preferably a hydroxide solution, which is preferably alkaline. That is, it may be any one of potassium hydroxide (KOH), lithium hydroxide (LiOH), sodium hydroxide (NAOH) and the like.

The positive electrode 110 and the negative electrode 120 are disposed inside the battery case 101 filled with the electrolyte solution 103. The air in the compressed air storage tank 11 is forcibly supplied to the anode 110. At the anode 110, oxygen is supplied to the anode 110 to cause a reduction reaction to obtain electrons, and hydroxide ions are generated. 103 to the cathode 120 side.

The present invention may include an empty housing 111 having an opening 111a corresponding to the cathode 120 and an anode 110 disposed in the opening 111a of the housing 111. [ That is, a catalytically active layer 113 constituting the anode 110 is provided in the opening 111a of the housing 111 and a current collecting layer 115 constituting the anode 110 is formed And can be stacked on the catalytic active layer 113 and opposed to the cathode 120. The air injection pipe 117 is installed to penetrate the battery case 101 and the housing 111 and air in the compressed air storage tank 11 compressed by the air compressor 10 is supplied to the housing 111 through the air injection pipe 117. [ (111).

The housing 111 is fixed to the inner wall surface of the battery case 101 so that the opening 111a can face the cathode 120. The wall of the housing 111, which contacts the inner wall surface of the battery case 101, This is because the inner wall surface of the battery case 101 in contact with the wall of the housing 111 can be replaced.

The catalytic active layer 113 is a part where a reduction reaction of oxygen occurs and includes a catalytic material and a carbon material as a main part of a cell that directly affects the reaction. The current collecting layer 115 is a path through which current is supplied, And is made of a metal having high conductivity without causing corrosion caused by corrosion. For example, the current collecting layer 115 may be a Ni mesh, or may be a Cu mesh coated with nickel or a Ni foam having a high surface area.

The cathode 120 may be a metal plate made of pure zinc or a metal plate containing zinc. The cathode 120 may include a zinc compound or an azeotropic grade exhibiting electrochemical activity suitable for the cathode. The cathode 120 loses electrons when the discharge process proceeds, and zinc ions are formed in the course of the discharge, and the hydroxide 120 reacts with hydroxide ions through the separator 140 described below.

The cathode 120 is fixed to the inner wall surface of the battery case 101 through the U-shaped bracket 150 and can face the anode 110. The anode 120 is connected to the anode 110 through a metal filter And a separator 140 may be provided between the metal filter 130 and the anode 110.

The metal filter 130 and the separator 140 are sequentially fixed to the bracket 150 that fixes the cathode 120 so as to be stacked from the cathode 120 toward the anode 110, . At this time, the metal filter 130 may be stacked at a distance from the cathode 120 to form the space S, and the separation membrane 140 may be stacked on the metal filter 130.

The metal filter 130 may be in the form of a perforated plate, a mesh or a foam. For example, the metal filter 130 may be formed of a perforated plate made of a nickel material, a Ni mesh or a Ni foam It can be either.

The separation membrane 140 serves to prevent other substances other than hydroxide ions from passing therethrough and has safety for the electrolyte solution 103. In addition, the separator 140 should be of good ion conductivity, electrically nonconductive, and stable for voltage and current stimulation of charging and discharging. When such performance is achieved, any material can be used as the separation membrane 140.

During the discharging process of the battery, the cathode 120 is dissolved in the electrolyte solution 103 as zinc ions. In the filling process, the dissolved zinc ions are again precipitated into metallic zinc, and zinc is precipitated as dendritic crystals. In the present invention, the zinc ions of the cathode 120 dissolved in the electrolyte solution 103 during the discharge process are converted into metal zinc in the charging process by the irreversibility of the charge and the discharge reaction due to the irreversibility of the charge and the discharge reaction. A part of the metal is passed through the separation membrane 140 and the metal filter 130 to be reduced to the cathode 120 and the remaining part of the separation membrane 140 is formed of metal zinc in the space S and zinc dendrite The generated job does not occur. In particular, the metal zinc generated in the space S electrically connects the metal filter 130 and the cathode 120 during the discharge process to improve the output.

Therefore, the zinc dendrite formed in the electrolyte 103 increases the irreversibility of the charging and discharging reaction, thereby substantially eliminating the existing problem of causing the capacity and the cycle life of the battery to deteriorate, so that the performance of the battery is greatly improved and maintained for a long period of time .

On the other hand, the electrolytic solution 103 circulates through the electrolytic solution tank 35 through the circulating motor pump 33 provided in the middle of the circulation line 31. As illustrated in the figure, the electrolyte 103 is repeatedly circulated through a cycle in which the electrolyte 103 is discharged from the lower portion of the battery case 101, passes through the electrolyte tank 35, and then flows into the upper portion of the battery case 101, The tank 35 separates the zinc particles or the zinc oxide particles contained in the electrolyte 103 after the reaction and precipitates the zinc particles or zinc oxide particles, and then supplies the zinc particles or the zinc oxide particles to the battery case 101 again.

1, the present invention can increase the charging and discharging cycle of the battery by replenishing the electrolyte 103 into the battery case 101 through the electrolyte replenishing tank 40. [ There is a problem that the _secondary battery is not charged or discharged due to the formation of carbonate in the electrolyte solution 103 and the electrolyte H ₂ O loss due to water evaporation or the cycle of charging and discharging is not long and the life of the battery is shortened. The battery 103 can be charged and discharged by replenishing the electrolyte 103 to the battery case 101 through the electrolyte replenishing tank 40, and the cycle can be greatly increased.

As described above, according to the present invention, zinc particles or zinc oxide particles having a small size contained in the electrolyte solution 103 after the electrolytic solution 103 is circulated after the reaction are further separated, and the electrolytic solution 103 required for charging and discharging is supplemented, The charging and discharging cycle is increased, and the lifetime of the battery can be greatly improved.

In addition, according to the present invention, air supplied from the outside of the battery is supplied to the electrolyte solution 103, and microbubbles are generated in the electrolyte solution 103, so that the performance of the battery can be greatly improved and maintained for a long time.

2, air supply means 160 connected to the compressed air storage tank 11 is installed in the inner bottom of the battery case 101 so that air can be injected into the electrolyte solution 103. As shown in FIG.

Although not shown, the air supply means 160 is formed in a tubular shape having a plurality of nozzles along its length, and is pierced on the inner bottom of the battery case 101 in a zigzag or spiral form, and is supplied through the battery case 101 The air from the compressed air storage tank 11 can be supplied to the electrolytic solution 103.

As shown in the drawing, the air supply means 160 is formed in a plate-like shape having a plurality of nozzles 163 formed therein with a pathway 161 and connected to the pathway 161 to penetrate the battery case 101 The air from the compressed air storage tank 11 supplied to the electrolytic solution 103 can be supplied to the electrolytic solution 103.

The air from the compressed air storage tank 11 is supplied to the path 161 of the air supply means 160 and is discharged through the nozzles 163 and injected into the electrolyte 103. At this time, the air supply means 160 forms a through hole 165 through which the electrolytic solution 103 passes, and is installed at a distance from the bottom of the battery case 101, It is preferable not to disturb the movement of the electrolyte 103 discharged from the electrolyte. The flow path 161 is formed inside the air supply means 160 along the periphery of the through hole 165.

The micro bubble is generated in the micro bubble generating means (60). The micro bubble generating means 60 includes two metal members 61 and 63 disposed at a distance from each other and located inside the battery case 101. The positive and negative poles of the power source are connected to metal members 61) 63 so as to generate microbubbles between the metal members 61, 63, and supply the microbubbles to the electrolyte solution 103.

1, the micro bubble generator 60 is located outside the battery case 101 and controls the power supplied to the metal members 61 and 63 to adjust the amount of microbubbles generated , And can be operated by receiving power from the power supply means (50).

The micro bubble generating means 60 may be constructed by fixing the metal members 61 and 63 to a fixing member having any shape such as a cylinder or a rectangular tube so that the micro bubble generating means 60 may be provided on the bottom of the battery case 101 separately from the air supplying means 160 And the metal members 61 and 63 may be fixedly installed in the through holes 165 of the air supply unit 160 as illustrated in FIG. That is, the micro bubble generating means 60 can be installed so that the two metal members 61 and 63 are exposed across the through hole 165, and the power from the micro bubble generating means 60 is supplied to the air supply means (61) and (63) through the inside of the metal member (160).

The viscosity of the electrolyte (103) increases as the ZnO increases due to the chemical reaction, and since such viscosity interferes with the movement of the hydroxide ion, the higher the concentration, the more the performance of the battery is affected. In addition, not only the oxygen required for the reaction exists in the air used as the anode 110 but also carbon dioxide which increases the viscosity is present. Carbon dioxide forms carbonate in the electrolyte 103 and increases the viscosity . As the viscosity of the electrolyte solution 103 increases, ionic conductivity is lowered to prevent the movement of ions, thereby affecting the performance of the battery. In the present invention, air is injected into the electrolyte solution 103 and microbubbles are generated, The viscosity of the battery can be maintained at the initial state and the performance of the battery can be greatly improved and maintained for a long time.

Bubbles may be generated during the charging process of the battery, so that the internal pressure of the battery case 101 may be increased. This is because the internal pressure of the battery case 101 is higher than the air pressure so that the electrolyte 103 can leak through the catalytic active layer 113 of the anode 110. As a result, And the catalytic active layer 113 is oxidized. In the present invention, since the compressed air having an internal pressure higher than the internal pressure of the battery case 101 is supplied to the anode 110, such a problem is fundamentally eliminated .

4, the cathode 120, the metal filter 130, and the separator 140 may be arranged in a plurality of sets on the inner wall surface of the battery case 101 as one set, The battery case 111 has a plurality of openings 111a and is installed at the center of the inside of the battery case 101 so that the openings 111a can correspond to the set. It is apparent that the openings 111a are provided with the anodes 110 corresponding to the set.

As shown in FIGS. 2 to 4, a charging auxiliary electrode 180 may be installed in the battery case 101. The charging auxiliary electrode 180 is made of a conductive material such as metal and is used as a positive electrode in the charging process. The charging auxiliary electrode 180 is provided to penetrate the inside and the outside of the battery case 101 adjacent to the anode 110 and serves as an auxiliary for preventing the anode 110 from being damaged.

It is also obvious that the battery case 101 may have a size or an overall geometry suitable for a battery or applicable to any environment and may have a rectangular shape, a square shape, an ellipse, a circle, or other suitable shape, It is obvious that the components are designed and applied to the shape of the battery case 101.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined by the appended claims. It will be possible. The scope of the present invention is defined by the appended claims, and all differences within the scope of the claims are to be construed as being included in the present invention.

10: air compressor 11: compressed air storage tank
31: circulation line 33: circulating motor pump
35: electrolyte tank 40: electrolyte replenishment tank
50: power supply means 60: micro bubble generating means
61, 63: metal member 100: zinc air secondary battery
101: Battery case 103: Electrolyte
110: anode 111: housing
111a: opening 113: catalytic active layer
115: collecting layer 117: air inlet tube
120: cathode 130: metal filter
140: separator 150: bracket
160: air supply means 161:
163: nozzle 165: through hole
180: Rechargeable auxiliary electrode

Claims (9)

In a zinc-air secondary battery,
Electrolytic solution;
anode; And
And a negative electrode comprising zinc,
A metal filter disposed at a distance from the cathode toward the anode to form a space;
And a separator provided between the metal filter and the anode,
Wherein the zinc ions are reduced to the negative electrode through the separation membrane and the metal filter before the zinc ions are precipitated into the zinc metal in the charging process, and the remaining zinc ions are generated as metal zinc in the space.
The method according to claim 1,
Wherein the separation membrane is stacked on the metal filter and faces the anode.
The method according to claim 1,
And the air supplied from the outside of the zinc-air secondary battery is injected into the anode.
The method of claim 3,
Wherein the positive electrode is installed in an opening of the housing and the air supplied from the outside of the zinc-air secondary battery is injected into the inside of the housing, Secondary battery.
The method according to claim 1,
Wherein the electrolyte is circulated through the inside and the outside of the zinc-air secondary battery.
The method according to claim 1,
And an air supply means having a nozzle for supplying air supplied from the outside of the zinc-air secondary battery to the electrolytic solution.
7. The method according to claim 1 or 6,
A micro bubble generating means for generating micro bubbles in the electrolytic solution by supplying positive and negative poles of the power source to the metal members and having two metal members disposed at a distance from each other, battery.
The method according to claim 1,
Wherein the electrolyte solution is replenished from the outside of the zinc-air secondary battery.
The method according to claim 1,
Further comprising a charging auxiliary electrode provided adjacent to the anode.

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